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Guide to Audio Basics

Last response: in Home Audio
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August 25, 2011 3:11:24 AM

Basic Guide to Audio:

This guide is designed to be used as a reference for people interested in general aspects of audio. I will try keeping things simple and I will not go into tremendous detail. This is also is not meant to be politically correct, because without making minor generalizations from experience, the information will not be useful for you. So in this guide, I am giving factual information as well as advice from experience.

Table of Contents:

-Terms
-Equipment (Amplifiers, Pre-amplifiers, Integrated Amplifiers, Receivers)
-Types of Speakers (Electromagnetic, Electrostatic), (Dome, Ribbon, Cone)
-Electricity
-Speaker Placement
-Sources (Bit-rate, sampling rate, bit depth, file formats)
-Connections (Digital, analog, TosLink, Coaxial, 3.5mm)
-Specifications (Speakers, Amplifiers, Pre-amplifiers)
-Subwoofers (Types, Terms)
-Acoustics
-List of Recommend Brand Names


Terms:

1)Digital vs analog:
Perhaps one of the most common terms in audio is digital and analog. The two are very different and many times mis-understood in their fundamental meaning so it is hard to explain but I will take a shot in making the explanation simple. Let me start by saying that all of the audio you hear is analog in nature...and yes, all audio systems no matter if the source and connection is digital-based, will eventually convert this signal into analog for playback. Analog and digital are fundamentally very different. All sounds you hear are analog and if you were to represent them in a graph, it would be a single and continuous line (yes it will vary based on amplitude, frequency and such, but I will not get into that complex material). Digital on the other hand is very different. If you were to represent a digital signal in a graph, it would be separate dots next to each other, not a single line. This is because digital is based on samples. Each dot would be a sample.

Just like movies are recorded at 60fps for example, digital audio signals are also recorded in samples, except instead of calling it fps (frames per second), it is just called “Sample Rate”. Common sample-rates for a regular CD track would be 44100hz. This means that every single second, there are 44100 dots or samples of the sound recorded and then played (measured in hertz). Now, just the same way as in movies, between each sample you miss some data, just like between every movie frame, you are missing some movement. To compensate for this, the frame-rate per second is increased in movies until your eyes cannot notice the difference and the movie instead of being choppy is smooth like real life.

With sound, no matter how infinitely high your sample rate is, there is always some time between each sample which is why the amount of data is never 100% like it is in analog. It is almost like a mathematical asymptote. However, going back to the line represented by the analog (continuous) and the line represented by digital (dots). If you took those dots of the digital signal and made more of them however...(increase sampling rate), to the point of where the dots are so close to each other that from a distance, to your eyes, it looks like a continuous line, then your digital signal would be losing an unnoticeable amount of data and would sound as realistic as a real sound. That is why sampling rates are high, such as 44100 times per second. At such a high sampling rate, just like with a 60fps movie, the sound would be heard excellent since a tiny amount of data is lost that is unnoticeable. All audio systems at one point have a DAC (digital to analog converter) to let you hear it. So I hope this was easy to understand on the differences of digital and analog in relation to audio. This is not easy to explain so bare with me.



2)Distortion:
Another very common term in audio is distortion. Fundamentally, distortion in audio refers to any sound that was not originally meant to exist when played and something that is not in the original recording. There are different types of distortion and it can be caused from a variety of factors. The source can cause distortion, the amplifier can cause distortion (harmonic distortion), and the speakers can cause distortion. The environment can also cause it. A properly made theater will have special acoustic treatments in the room so that there are no reflective surfaces which can spoil the surround effect, just as a side note.

3)Decibel:
Commonly used measurement of sound volume or output. This is the unit to describe speaker efficiency and sensitivity.

4)Modulation:
AM and FM radio are types of modulations. Modulation is modifying the sound curve. AM is based on amplitude modulation and FM is based on frequency modulation, they are two different things entirely and have different properties.

5)Crossover:
Crossover basically takes the audio signal and divides into specified frequency ranges so they can be sent to different drivers designed to handle it. For example, the low frequency range would be sent to the largest woofer. The highest frequency range would be sent to the tweeter. The reason for this is, because the tweeter would have a lot of trouble playing low frequencies and the woofer would have trouble making really high ones. There is a signal crossover and a physical crossover. A signal crossover is setting what frequency ranges are sent to what speakers on your pre-amp. A physical crossover is an actual system of filters inside the speaker itself. Crossovers are made by coils and capacitors. Under AC power (DC is not used in audio systems at all), a capacitor (depending on its specifications), resists low frequencies while letting higher frequencies pass through. Therefore, using systems of capacitors, filters are created for the tweeters so low frequencies aren't sent to them. On the other hand, a coil is the exact opposite. A coil lets low frequencies pass while blocking higher frequencies. This is why coils are used as filters for the low-range woofers. Physical crossovers cannot be bypassed by a pre amplifier. Also, under DC current, a coil and capacitor act entirely different which is why the electricity supplied to your speakers is always AC or in otherwards...DC current that is emulated as AC using positive and negative voltage to modulate it. A speaker can work on modulated DC. You need AC for a driver for it to go backwards and forwards past its resting point/middle point. If you use variable DC however you can still make it forwards and back to zero to create sound technically. As far as mainstream goes...its AC.

6)Driver :
This is a device that produces sound. A speaker is usually a combination or group of drivers working simultaneously. A common three way speaker has three drivers. A bass driver, a midrange driver, and a tweeter for the highest frequencies. A driver (the electromagnetic ones) consist of a magnet, coil, cone...etc.



7)Noise:
Noise, for the average person is a hiss made by speakers. Noise is commonly caused by interference. In many systems, noise can originate from poorly insulated wires picking up interference or the circuitry inside the equipment.

8)Resonance Frequency:
You've probably heard of the term before when talking about speakers. I am not going to go into detail about what it means, but in simple terms a resonance frequency is a frequency that you do not want to play on your speaker or driver. A drivers resonance frequency is basically at which it provides the maximum output which usually results in major distortions. That is why special filters are made to cut a speakers resonance frequency off most of the time.

9)HTIB: Home Theater in a Box. This is a common solution which provides a receiver, subwoofer, and 5 or 7 speakers all in one box.

10)Impedance vs Resistance: Everything has some form of resistance, even the most conductive materials on the planet (such as copper, silver...etc) have some form of resistance. Speakers are adjusted accordingly to have certain resistances. Every speaker has a certain overall resistance. Most speakers have 4-10ohm. You might ask why it always says Impedance instead of resistance when talking about this subject on speaker specifications. Well, impedance is a resistance. Impedance is just resistance on a certain frequency or frequency range. I don't want to get into scientific detail about this, although I can, but this the simplest I can put which you should know.

11) Parallel vs Series Wiring: Parallel wiring is just taking two speakers and wiring them in parallel...this significance to this is that it effectively halves your resistance. So if you take two speakers with an 8ohm resistance/impedance each and wire them in parallel, your overall resistance/impedance would be 4ohm. So by this you can overload your amplifier is it will be feeding much more power then it is designed to do. An amplifier has a power supply that has its limits so if you think you can get free extra power by lowering impedance...you're fatally (fatal for you amplifier that is) wrong. As long you stay within your amplifiers limits, you technically can wire in parallel, but always be careful. Series wiring is opposite on the other hand. This doubles your resistance. So instead of 8ohm for example, your resistance would be 16ohm now. So your speakers would be quieter now (theoretically), because their resistance to your amplifiers power is much higher now. You can also do a trick. If you take 4 speakers of 8ohm and want to wire them together and maintain an overall impedance of 8ohm. Well, you can use both parallel and series wiring in your circuit and have 4 speakers and still maintain a safe resistance of 8ohm.

Equipment:

Amplifier: An amplifier is a device used to amplify a signal. A sole amplifier can do nothing but amplify a signal. The main two amplifiers that I know of and how they work are Solid-State amplifiers and Tube amplifiers. Solid-State amplifiers use semi-conductors called transistors to amplify the signal. Solid-State Amplifiers account for the far majority of amplifiers today. Tube amplifiers are older technology which uses heated tubes (I won't go into specifics about how they work). Many people say they sound different and to each his own, however many say that a good tube amplifier will create less noise. All transistors create some form of noise, its just how they work.

Preamplifier: A preamplifier is basically the brain or control system of an audio system. Your accessories such as your TV, DVD player, network player...etc...all connect to your preamplifier. This is the device that does sound processing such as surround effects and such. Your amplifier is just the pure muscle of the system. Your amplifier is also connected the preamplifier if you were wondering.

Integrated Amplifier: An integrated amplifier is basically when you take an amplifier and preamplifier and put it into one single box or enclosure. This is instead of buying separate units.

Receiver: This is the most common product today. This combines an amplifier, a preamplifier and a radio tuner for FM/XM/AM into one single enclosure. It is probably the most common form bought on the market.

Equalizer: An equalizer allows you to boost or suppress certain frequencies which is very beneficial for music. There are physical equalizers and software equalizer. I highly recommend using one if you are a big music listener. It makes all the difference. Speaking of equalizer, I wanted to talk a little about this and perhaps clarify some confusion. Many people will say that using an equalizer takes away from the "pure" sound, because it messes with the ratio of frequencies and isn't good. Well, let me explain. It is very easy to create a linear frequency response from an amplifier...not very expensive and is quite common. However...with speakers, creating a *Flat* frequency response is extremely difficult. Speakers that cost 10, 20, 30, 100 thousand dollars are expensive partially, because they have a flatter frequency response which requires tons of research and engineering perfection. Getting the same efficiency at different frequencies is not easy. So if you had a perfect speaker with a perfectly flat frequency response (impossible), or maybe at least close...then you wouldn't need an equalizer. However a speaker like that will cost you six figures easily. So unless you have a system thats at least six figures...using an equalizer to boost some frequencies that the speaker has trouble with is perfectly okay. Not to mention most music today isn't made from instruments...its mostly electronic with special signals being fed into the track using software. Since music is mostly electronic, the recording ALREADY comes from speakers meaning the frequency response will already be tampered with and cannot be perfectly flat. Classical music that uses only real instruments can have the ability to deliver a true flat-response assuming your speakers are capable. I have a very decent grade Hi-Fi audio system and even I happily use an equalizer that I tweak for almost every song a bit differently to get that perfect sound. Adjust the high's, mid's and low's the way I want them.



DAC: Digital to analog converter. All audio systems have one (if they use a digital source of any kind that is), most of the time it will however be built into the receiver or integrated amplifier. Some DAC's are better than others also.

Bi-Wiring/Bi-Tri-Amplification: I have never heard of more than bi-wiring. However, as it is, Bi-wiring means running two sets of speaker cables to each speaker. Some speakers allow such feature which can provide some theoretical advantages. Bi or tri amplification is very interesting on the other hand. In most audio systems, you have a signal amplifier powering all speakers on all frequencies. However, if you need more power what you can do is use multiple amplifiers. In these systems, separate amplifiers power separate ranges of frequencies. For example, in a bi-amplification system, I would have 2 (hence “bi”) amplifiers and using a crossover, I would use the first amplifier to operate at a range of 20hz to 10Khz (just an example) and my other amplifier would power from 10Khz to 20Khz. In a tri amplification system, I would have three amplifiers with three ranges. Yet another way to set up an audio system on the other hand is to have a separate amplifier for each speaker. Some higher end companies such as Marantz Audio and McIntosh are prime manufacturers of one channel amplifiers. You would need a separate one per speaker. This is probably the most expensive and high end method of powering an audio system.

Types of Speakers:

Speakers: There are two (maybe more that I'm not aware of) main fundamental types of speakers that are made in terms the methods they work in. There are electromagnetic speakers (the most common) and there are electrostatic speakers. Electromagnetic speakers use a magnet to drive it. A cone is basically the surface that displaces air. Electrostatic speakers are very different. These speakers have a thin film between two electrically charged grids which displaces air. Electrostatic speakers are usually very thin and currently are capable of producing mainly high and midrange frequencies, they have difficulty with low frequencies which is why they are usually accommodated with an electromagnetic driver for the bass. Martin Logan is a prime manufacturer of electrostatics. Personally, I think that high and midrange sounds are far superior in electrostatic speakers. It sounds cleaner and crispier, mainly due to the fact that the film can move much faster than a cone on an electromagnetic driver and produce more accurate sound in complex sources. Which is why I own a pair and love its sound. Do not sweat though, electromagnetic speakers are far more popular and good ones make excellent sound.

Tweeters: Most tweeters are electromagnetic based. However there are many different types of tweeters specifically. There are regular cone tweeters which are just mini-versions of the larger drivers. However there are also dome tweeters, ribbon tweeters, horn tweeters...etc...they are all electromagnetic but create sound through some different methods and have different properties. Dome tweeters are popular because they disperse the sound quite wide which helps a lot since higher frequencies are heard very directionally by human hearing.

Electricity:

Electricity is what makes audio work. A lot of misconceptions are out in the wild as how amplifiers actually work that I'd like to clear up. First off lets start with the clear and honest fact that amplifiers don't actually amplify electricity. Transistors are an amazing invention, but a transistor cannot create more electricity from less electricity. If transistors really could spontaneously generate more electricity while consuming less then our world as we know it would probably be a lot different (greener, less expensive, more advanced). However that's not the case. Transistors are in its simplest form a variable relay. All a transistor does is use a small amount of current to control a larger amount of current. An example of a simple relay is an elevator switch. Imagine that you are pressing a tiny button and that button activates a giant mechanism/engine/motor that carries thousands of pounds at a high speed along a vertical shaft in a building. Do you have any idea of the absurd amount of current in that system?...and you are controlling that entire system with a tiny button that uses almost no current. That is an example of a relay system. The benefit of a transistor however is its ability to fine tune that control meaning it can be adjustable. In electronics you often have pieces that are static or adjustable.

You can have a resistor or you can have a rheostat/potentiometer (you literally turn a knob to adjust resistance)
You can have a capacitor or a variable capacitor that can be adjusted as you please (within a certain range of course)

Thats what makes transistors interesting. Allowing them to be used in a limitless amount of applications in electronics. This website right here provides an EXCELLENT analogy of how they work:
http://www.satcure-focus.com/tutor/page4.htm

Now...lets talk about current. Transistors only work on direct current. However speakers need current that acts like alternating current (I'll explain why I said *acts* later). Real alternating current is produced by an alternator like a turbine that naturally makes this kind of current. I can assure you however that there is no spinning turbine inside you amplifier. What actually happens is your amplifier is giving your speakers Direct Current to *act* like Alternating Current. It will provide a positive and negative Direct Current so your driver moves both ways and then it will adjust frequencies based on the sound required. Alternating Current will have a 60Hz frequency in your outlet, but speakers need varying frequencies. So everybody will tell you that speakers always use Alternating Current, which is true however it is merely Direct Current that is artificially made to act as if it were alternating current. This is also important for capacitors and coils to work properly as filters of frequency in the electronic signal so your speakers play sound correctly. Your subwoofer can't play a 20,000hz signal and your tweeter cannot play a 20hz signal, which is why crossovers and filters are made.

Speaker Placement:

This is placement for a standard 7 channel surround sound for Blu-Ray movies.

Subwoofer Placement: Yes, low frequencies are extremely omnidirectional to human hearing, so you can technically place your subwoofer anywhere to hear its frequency range. However, subwoofer placement DOES matter. Due to room acoustics (which are affected by the walls, floor, ceiling, furniture, and materials), the placement of your subwoofer can create areas of extreme bass and areas with virtually no bass. Moreover, if you place your subwoofer into a corner or closer to a wall, the bass will likely sound louder to you. The sound will also sound boomier and less quality. If you place your subwoofer further away from a wall or corner, the bass will sound quieter but a bit better quality (as in less boomy). At least that’s how it is for me and for many.

Center Channel: This is debatable the most important speaker in a home theater system (not a music system). The far majority of a movie's audio track will be sent to the center channel. It is therefore essential that the center channel is capable and well placed. Since the center channel plays mainly dialogue and high frequencies, I recommend it be placed in the center of where you are looking (the screen) and be just above or just below it. If your center channel is directly above or below your TV, if possible, I recommend tilting it upward or downward slightly to be pointed at your head. Higher frequencies are directional and need to be pointed at your ears for best affect. However it is not the end of the world if you cannot tilt it.

Front Speakers: On the internet, many recommend having them at a 45° angle towards you. I also recommend this for best affect, especially if your tweeters are regular cones. However, if you have dome tweeters then you have more freedom on placement since they disperse high frequency sound better and wider.

Surround Speakers: The best placement for these is directly to the sides of you at the height of your ears. If they are above you facing downwards, it is also fine.

Rear Surround Speakers: The best placement for these is directly behind you at ear level. This would be your standard blu-ray 7 channel surround sound. Sometimes, people have 6 channel surround which means just one rear speaker instead of two. In this case, your one rear speaker would be in the center behind you at ear level optimally.

Types of Surround Sound:

First off, let me clarify that the .X behind every surround sound specification just means the LFE (low frequency effects) channel or AKA subwoofer. In a 5.1 system, you would have one subwoofer and 5 channels while in a 5.2 system, you would have two subwoofers and 5 channels.

Stereo: This is standard and basic two channel which is meanly used for music

5-Channel: This is the most common surround sound format. Regular DVD movies and TV uses 5-Channel surround sound. Most have one subwoofer which is why it is designated as 5.1.

6-Channel: This is less common, but is a step up from 5-Channel. Here you have one extra speaker behind you for added affect.

7-Channel: This is the new standard which has two speakers behind you added on top of your 5-Channels. For better LFE, many receivers now feature 7.2 instead of 7.1 which allows two subwoofers.

9-Channel: No source has been encoded in this format yet, but many receivers processes this for added effect such as a deeper or wider sound stage. In 9-Channel, you usually have the option to add two speakers on the very wide extremes of your room, outside of your regular front speakers for a wider sound stage effect. Or you can add two speakers above your main speakers which usually creates a deeper and more three-dimensional sound stage effect. Whichever you like.

11-Channel: Some receivers even have 11-Channels where you can add both height and wide speaker channels for effect. I've also heard you can add, lets say, two front wide speakers, and two more speakers behind you for presence and better effect. The only receiver I've seen that does this is made by Yamaha. You can check it out at their website.

Sources:

This is a commonly ignored area of quality in relation to audio systems. The source of the sound makes an absolute day and night difference in quality a lot of times. The most common source are mp3 files probably. The main specifications of an MP3 file are the bit-rate, sampling rate, and bit depth. Sampling rate is just how many samples of sound are taken. The more often samples are taken, the wider the frequency range is. Each dot that represents a sample as we spoke of earlier also has a property...bit depth. This is how well it is described. Bit rate is the information transmitted. Its hard to explain.

Sample Rate: Sample rate is how many samples of the song are take per second. If we go back to the graph in the beginning of the post where I explain digital versus audio you can see this. If you use some calculus, on this graph you can see the the digital samples are related to a Riemann sum. When you use Riemann sum, the area will always be a little smaller than the actual area under the curve or aka the Integral. You would need an infinite amount of samples to approach the actual area of the analog source...which is essentially what analog is, continuous. So the more samples you take the more realistic it is. However, it gets to a point so high that you really cannot notice which is why there are certain limits today to sampling rates on most audio (44Khz).

Bit Depth:: This is no another specification. Bit Depth is the depth of each sample. In sample rate, you take lots of samples, but bit depth is how *good* each sample is. Higher bit depth makes a higher noise/signal ratio technically.

Bit Rate: : This is just a calculation of the sample rate and bit depth. It relates more to how much space you need for every one second of music. It also takes into account channels. If you have stereo recordings which practically all are today, then you take sample rate multiplied by bit depth and then by two for two channels. Bit rate related to file size mainly. I am not sure, but as far as I know, for compression based formats, bit rate relates to other quality factors to achieve its size variability while keeping a certain standard.

Connections:

Connections are also very important in audio. There are two main types of connections...Digital and analog. However there also different types of factors that affect the quality of both. SPDIF (Sony and Phillips Digital Interface) is a digital connection commonly used today. It can carry multiple compressed channels through it. Digital connections such as fiber optic and coaxial are SPDIF if I am not mistaken. It is a set standard used pretty much universally. In most modern home theater systems, the receiver is used a centralized unit which makes for far less wires and much easier operation. Let me explain why. Before modern receivers, before HDMI, the hookup was extremely painful. For every single component (cable box, DVD player, network player, VCR...etc) you would have to run a wire to the receiver for sound and then run a separate wire to the TV for video. This means that you if you had a set-top box, DVD player and a network player, you would have to run six cables total from just those three components for audio/video. With modern receivers however it is far easier. Now with the use of HDMI, all of your components use one single HDMI cable to one input on the receiver and then one single cable from the receiver to the TV. So each component only has one wire now. The receivers can now run video and even 3D through their circuitry. Not only is wiring easier, but using it is easier. Before, you had to select the input on the TV and receiver for each separate device. Now, you just select the input on the receiver itself and that is it. It makes life easier and less complex operation of the home theater.

Digital Connections:

Fiber Optic TosLink: This is the highest quality digital connection. It uses light to transfer the audio signal and therefore is noise-free. Fiber optic uses TosLink connectors. So basically, its a fiber optic cable, just like any other, but it uses toslink connectors at its ends.

Coaxial: This is also a digital connection, probably more common also. This uses a physical wire to transfer the signal making is susceptible to noise. However before you drop money on a fiber optic cable, know that a well insulated coaxial cable will reduce noise to unnoticeable levels. Coaxial uses RCA connectors.

HDMI: This cable shares both audio and video. Same principle as a coaxial connection. Just put into one wire for convenience.

Analog Connections:

Standard 1/4'' and 3.5mm Jack: These connections can be found in sound-cards, computers, and headphone amplifiers such as in your receiver. They are analog.

Composite: Still, today many receivers feature composite connections (specifically for audio). This connection has two wires, one for each channel.


Specifications in hardware:

X watts at X Ohm: When you see this specification, for example "50watts at 8ohm" means that an amplifier can provide 50watts of power when provided a resistance of 8ohm. The resistance usually being your speaker. Speakers come in various resistances, the most common I've seen is 8ohm, but many come at 4ohm, 6ohm, 10ohm and other resistances. Now, suppose you buy an amplifier that says it can provide "50Watts at 8Ohm" and then suppose you bought speakers that have a 4Ohm resistance. This means that your amplifier would be able to provide 100watts of power to your 4ohm speakers theoretically (not always true due to power supply limitations and such plus increased distortion). You always need to be careful here, because if you connect lower resistance speakers to an amplifier not designed to handle it, you can overload and fry your amplifier, notice how I say you CAN fry your amplifier. Many will tell you that connecting lower resistance speakers to an amp not designed for it will automatically fry it, but that is not true...you just need to make sure you stay within its limit. I have a stereo amplifier that is designed for 8ohm and outputs 50watts per channel. Guess what? I have 4 speakers connected, 2 per channel wired in parallel which gives a 4ohm resistance. It still hasn't fryed, because I stay within limits. If you want to be safe, just buy speakers with the same resistance as the amplifier is designed for, or buy non-inductive resistors to your speakers to equal the designed resistance if you can understand. The reason non-inductive resistors are important is because they are made differently. Regular resistors use a coil for resistance which can block high frequencies, because after all...that is what coils are meant to do. However non-inductive are made different, perhaps with some chemical paste that lets high frequencies pass.

THD: THD stands for Total Harmonic Distortion, when you see this specification on your amplifier, it literally means what percent of the signal it receives that becomes distorted after being amplified. We can all agree that too much distortion doesn't sound pretty so you want to keep it as minimal as possible. Distortion can come from everything, the amplifier, the speakers, the source, even the environment and materials. When you see the distortion levels of your amplifier, most have a 0.08% level. Very high end amplifiers have even less, but at such low levels anyway, your speakers are far more likely to produce distortion first than your actual amplifier. The thing about THD is that is commonly used by manufacturers to a huge advantage. Many people now a days just look for and brag for systems that output the highest wattage on the specifications tag without caring about any other of the variables. Some manufacturers like to claim a much higher wattage output but then say that the amplifier produces 10% of harmonic distortion...folks 10% would sound horrible on any decent pair of speakers. So watch out for those tricks. If you want to stay safe from tricks and marketing gimmicks and just want a good solid sounding amplifier then stick with the recognized and reliable brands. Ill provide a list of brands that I personally think are the best around at the end of the guide.

Signal-Noise Decibel Ratio: This depends on lots of factors of the receiver and it also depends on the source itself which can limit the ratio. However, for you what is means essentially is how much noise your amplifier or receiver makes when playing. This doesn't account for cables...this is just the sole circuitry inside the enclosure of the receiver. The higher the ratio, the less noise your amplifier will make. The highest signal to noise decibel ratio that I have seen is on a McIntosh producing 129db...which is ridiculous. At even low volumes, high noise is almost unnoticeable. Really, the only time you will notice noise is when playing a song very loud and all of a sudden, a quiet part comes through or it becomes silent. Most receivers today are over 100 anyway which is excellent. Even just below 100 is still fine. Unless you are a picky listener to a very specific type of music...I wouldn't worry much about this personally. Just make sure your cables are reasonable insulated and you will be fine. In movies, with all the complex sounds, I doubt you would notice anything on even a cheap amplifier with a low ratio.

RMS and Peak Power: Lets get something straight, when you buy an amplifier, the peak power does not matter. Peak power is how much power your amplifier can deliver in one single instant burst. Anything more than an instant could fry it. Therefore RMS power is far more important to look at, this is how much power your amplifier can continuously deliver. Peak means just tossing into the circuit a beefy capacitor.

Advertisement on separate power supplies per channel: Many manufactures claim that instead of having one powersupply for all channels, each channel has its own power supply and is therefore better. This is a myth, a properly made power supply can be used to drive all channels. Instead of having smaller power supplies driving each channel, you have one large driving all of them. There is no difference and is just a gimmick.

Bandwidth: This is what range of frequencies the amplifier can produce. Human hearing ranges from ~20hz-~20Khz. If an amplifier claims it can do that, doesn't necessarily mean your speaker can. So when buying, compare this specifications with the range of your speakers. Remember, amplifying lower frequencies takes a lot more power so an amplifier that claims to output 100watts at 1Khz may only output 20watts at 30hz and if it gets higher then sound will begin to distort.

Weight: Heatsinks and power supplies weigh a lot...so when you buy a receiver that claims 1000watts and weighs 20-30lbs...ask yourself this: Why does a different brand receiver of the same wattage weigh 40-50lbs?...I can tell you they don't put bricks into their amplifiers. Amplifiers that produce lots of power needs lots of powerful transistors which get very hot and in turn must be cooled by large metal heat-sinks. In audio, from experience I can tell you that weight usually equates to quality. Not always...but usually.



^This image is from http://usa.denon.com/us/Product/Pages/Product-Detail.as...

All credit goes to Denon.

Specifications in Speakers:

Crossover: Inside speakers that have multiple drivers, physical crossover systems exist. This is to prevent frequencies too high or too low to play on a certain driver. If you are wondering, crossovers are mainly made of coils and capacitors. Coils are mainly used for the subwoofers to block high frequencies from being played while tweeters usually use capacitors to block lower frequencies.

Efficiency: This specifications tells you how much electrical power a speaker can turn into acoustical output. For example, one speaker can produce an X amount of power when supplied with an X amount of watts. While another speaker can produce 2X amount of power when supplied with X amount of watts. So if your amplifier is very weak for example, you'd generally go for more efficient speakers to get better volume.

Size/Weight: Powerful speakers with a broad frequency range, specifically ones that can produce bass need a good and stable enclosure and a powerful driver. Powerful drivers generally have large and powerful magnets...magnets are heavy. Good non-vibrating enclosures are also heavy. Just like what I said with amplifiers...weight generally(Not always) equates to quality in my experience with speakers and amplifiers.

PowerRMS/Peak: Just like RMS and PEAK power that an amplifier can produce without being damaged, a speaker has a RMS and peak power that it can take without being damaged. If you take two speakers of the same efficiency with one having a higher RMS, it generally (not always) means that the higher wattage speaker will get louder before producing distortion or getting damaged.



^This image is from http://www.klipsch.com/p-39f-floorstanding-speaker
All credit goes to Klipsh

Subwoofers:

Man, subwoofers have a lot to talk about. For Bass lovers such as myself, subwoofers are essential to get that low frequency teeth-rattling punch from music and movies. Lets first start off with the fact that subwoofers are just speakers that are specifically designed for the lowest frequency reproduction. Typically from ~20hz-200hz capability.

Subwoofers deserve their own section...to much to say about them.

-Sealed: This is the most basic type. A simple driver in an air tight enclosure. If you want to take my advice, sealed subwoofers generally create the best quality bass. By quality I mean accurate and undistorted bass. Bass that is punchy and strong, if properly made of course.

-Ported: This is the most common type of subwoofer. A ported subwoofer has an opening, or more in the enclosure allowing for air movement. Ported enclosures work a bit differently. Based on the tuning of the port (size...diameter and length...etc..) will determine how it will sound. You can tune a ported subwoofer to sound louder at certain frequencies. There are very good ported subwoofers that sound almost as good as sealed ones do.

There are also radiator based and bandpass enclosures as well as some others but they are far less common and I am not going to do into detail on them.

Debunking and explaining common misconceptions with subwoofers:

Bigger driver means more bass!: FALSE!, in fact in most cases, the size of the enclosure affects bass output more than the size of the driver. Up until a certain point, a larger enclosure will equate to louder bass output. When I say up to a certain point, I mean that eventually if the enclosure gets too large, it will act as just free space instead.

Multiple smaller drivers is better than one large one!: TRUE! Well...not always true. In an optimally sounding subwoofer, the enclosure would be sealed and there would be one VERY large driver. The reason a large driver is better is, because it needs to move less to produce the same sound meaning it has less excursion. This is beneficial because when a driver has massive excursions to produce sound, by the time it finishes moving out of the box or inside of it to finish a certain note, the signal would have already sent another bunch of notes and at the point, the driver cannot catch up. This can lead to inaccurate sound reproduction and distortion. That’s why a driver that has low excursion and moves very quickly would be optimal for the best sound. HOWEVER! with this comes a catch. If you take a large driver, say a 15'' or 18'' and make it vibrate extremely fast to catch up with the signal notes, the actual material of the cone itself can warp and move, which causes distortion. Of course a high quality cone material would probably compensate for this, but for this reason many times you will see subwoofers with one enclosure and multiple but smaller drivers in it. So instead of one giant 15'' or 18'' it would have two or three 8'' or 10'' drivers. If properly designed, the bass would still get as deep frequency wise, but the smaller cone would result in less warping of the fabric to reduce distortions even when vibrating extremely fast. To sum it up, optimally, for the best sounding subwoofer, you want your driver to move as fast as possible without warping the cone surface itself for the most accurate sound reproduction.

Common Subwoofer Terms:

Active vs Passive: This is a common term when referring to subwoofers. An active subwoofer is the most common. It’s a subwoofer that connects to the outlet and is self-powered. The amplifier for the subwoofer is inside of it. Therefore you don't connect speaker wire from your amplifier, just a signal cable to your pre-amplifier. Your main amplifier does nothing for the sub woofer. A passive subwoofer on the other hand is like a true regular speaker. You run speaker wire from your amplifier to your subwoofer. I've seen some HTIB (Home theater in a box) systems with this but other than that they are pretty unpopular according to my observations.

Front vs Down firing: Some subwoofers have a driver facing front towards you and others have one facing down at the floor. Other than resting assured my cat will not claw the driver of the front firing driver, I don't think there is much difference. I could be wrong though. I have some down and some front firing. There are huge debates online about this and it is not clear which is better. In a down firing subwoofer, the surface directly below it would probably affect sound more drastically if it is reflective or not. I recommend checking out the many wars online of front vs down and decide which one you want.

Acoustics:

Why acoustics are important and how they affect sound: Acoustics play a major factor in the quality of sound you hear, infact it can make a difference almost as much as your speakers themselves and often times for a cheaper price. A major issue with many sound system as that rooms have a plethora of furniture and objects in the listening space that tremendously impact sound. The problem with this is mainly reflection. Frequencies playing out of a speaker can reflect off walls and other objects a few times like bouncing balls before reaching your ear. This can also mess up the entire stereo listening effect, because sounds that are supposed to be predominately heard from the left side by the left ear, for example may be heard more from the right ear. In an optimally sounding space, you want your walls and furniture to absorb sound as much as possible to minimize reflections. Reverberation is based on these reflections. In an optimally sounding room, the reverberation would be equal across the entire frequency range. If reverberation is different for varying frequencies, it creates massive imbalances in the sound which make a room sound...bad. Professional and high end sound rooms are built from scratch with acoustics in mind. They build walls that insulate the sound and have treatment everywhere. For the most part, people do not really consider this when they build their home theaters or sound system so I am not going to go into much more detail about this, but now you know the fundamental "basics".

Small Section on Car Audio:

I know this a home audio forum, but a small car audio information section can help since there are the occasional car audio questions here anyway. The first thing I really want to get out of the way is that there is very common misconception amongst many people that seem to think that in order to have a good car audio system, you just need to hook up that sub woofer and you're good to go. Well let me tell you something, even if a having a good audio system just involved hooking up a subwoofer, its a lot more complicated than people think or it looks like. It boggles the mind. I know a bunch of people that say they are buying a subwoofer for the car. I ask them how will they hook it up? They say, "Oh, I'll just run the wires from the battery to the trunk, connect it to my amp and then connect that to my sub and head-unit". No, unless you have a very cheap, old, and simple car, hooking up a sole subwoofer is a lot more complicated than it looks. Assuming you have a subwoofer, amp, wires, and a head-unit ready for installation. You will need to run pretty thick wires from your battery to your trunk. This involves routing through all the complex electronics under the hood, then through the door systems and into the back. You need make sure you wires do not interfere with anything or touch anything hot. If you install this wrong, you have a risk of damage to your car or a fire, this is serious. Secondly, you need to route wires all the way up to your head-unit. You also need to properly connect your head unit, a mistake can cause damage to something in the car. On top of that, you need to properly place your subwoofer in the car and the amplifier to prevent damage. Every single pothole you hit, causes friction and shaking, which can mean the insulation of wires wears out, or components in your amp break and a bunch of other scenarios. However, nevertheless, let me explain some things you need to have a good-quality sound system. If I can hear your sound system outside of car, that automatically tells me you went the cheap route, did not do any kind of sound dampening and your car is just a giant rattle can, and it honestly doesn't give you bragging rights. If your headlights dim every time your subwoofer hits, that doesn't tell me your subwoofer is powerful, its just tells me you have a really bad system, because you have no constant voltage peak supply from a capacitor. Lastly, if all I can hear is distorted bass, without good mid-range and high notes, then thats not even an audio system, thats just an attempt at buying a big subwoofer, turning up the volume, and making noise pollution thinking people's jaws will drop as they watch you drive. Seeing all this stuff in college and from some friends, just shows itself. Now I'm going to explain some essential parts you need to have a good audio system, at least a minimum requirement for my standards.

The Amplifier: Obviously, you need a high quality amplifier. Wattage does not mean a thing in this aspect. When somebody tells you they have an 800Watt or 1500Watt sound system in their car, it only tells 10% of the story. Factors such as speaker sensitivity/efficiency, and impedance play a huge role in this, not to mention the exact car, and the enclosure. Try to match your speakers impedance's with your amplifiers ratings for best results. Mark Levinon makes some of the best car amplifiers and sound systems.

The Subwoofer: If you want quality music from inside your car, a decent sized subwoofer and enclosure is a must. The $50 10minute assembled kits you get from best buy are not okay. They are very bad if you want a decent sound system. They are cheaply made, unstable, not sealed properly and too weak. One pothole will likely make them fall apart. In addition, a good driver will have low excursion, not high. High excursion causes inaccurate bass and distortion. It also should have a powerful magnet and strong cone surface. For a sealant, I prefer rubber, instead of foam, it tends to be stronger in my experience.

Dampening: Since your car has tons of different components, lots of bass will make it rattle, especially the trunk. Not to mention people outside will hear it. If you want everything to sound solid, make sure your trunk is well insulated, your doors, and anything that rattles. Your music is played for you, not for pedestrians outside. Seal it up.

The Capacitor: This is probably the most important. Each powerful note of bass you play draws tremendous voltage. Something must give. Your battery will either make the bass sound like underpowered farts, or your headlights will dim (or other important things will lose power). Thats why a large capacitor to provide a boost is essential for both quality, and safety.

Tweeters/Mid-ranges: To have good high and mid-range frequencies, you want to have good tweeters and mid-range speakers. You may need to replace your current ones if they are bad. If you have bad vocals or high's, that automatically disqualifies you from saying you have a good car system.

Those the are basics!

My Personally Recommended Brands for Receivers/Amplifiers/Pre-amplfiers/Integrated Amplifiers:


-Denon
-Marantz Audio
-NAD
-Pioneer
-Harman Kardon

^These are great brands for receivers and amplifiers. For the price, they are usually the top dogs.

My Personal Recommend Brands for Speakers:

-Definitive Technology
-Bowers and Wilkins
-Klipsh
-Elemental Design Subwoofers
-Velodyne
-JL Audio
-JBL
-Martin Logan

^These manufactures make great speakers at a variety of prices. Generally the quality is good.

Remember please, there are hundreds if not thousands of different brands. As many speakers and amplifiers as I’ve heard, its nothing compared to what is out there. So when purchasing something, listen to what you ears tell you...not the salesman or the Internet. Your ears don’t lie, can’t say the same for another person.

Now I hope I've helped a lot with people of this guide! Please do not hesitate to comment on it and ask me to add something or correct me on something that I may have mis-stated.

Thank You!

More about : guide audio basics

August 25, 2011 1:48:51 PM

This topic has been sticky in top of the forum by Jpishgar
August 25, 2011 2:03:02 PM

bravo, about time all this information was mentioned in a fairly laid out post.

this should be stickied and referred to/read by people seeking advice to familiarize themselves before asking us questions. a MODERATOR should look at this. [EDIT: looks like it got stickied by the time i finished writing this!!]

keep up the good work.
---

you might want to briefly touch on the differences between "computer audio" and "home theatre audio"

s/pdif should be added to the optical connections listing.

analog connections should be listed, if just briefly

imo hdmi > coax since if you're going to be using one for video anyways.

for brand recommendations the words "budget inclined" give false representation. this leads one to believe they are brands for only people with little money to spend (for example under $500). for example my mid ranged pioneer receiver was $500 and i know they make even higher end models. my klipsh speakers were also around $500 (sub $350) and they are the lower end models. klipsh has sets which are over $10,000. i think you need to clarify this section a bit.

if you place down firing subwoofers on thick carpeting some of the sound will be muffled. to avoid this sometimes people place them on a hard board or other such platform. i've heard that down firing subwoofers are more omnidirectional and spread sound out better than forward firing models.

i agree with the weight comment in terms of audio equipment. i commonly use the reference with computer power supplies as well. a psu weighing 10-15lbs is a good thing (provided you dont try to actually lift your computer case!).

you might want to list a brief section on HTIB (home theatre in a box) solutions.

a small section on speaker placement and why running the "speaker test" to calculate speaker delay is important.

going over 2.1, 5.1, 7.1, multi sub setups: differences, pros, cons, etcetera might be nice.
Related resources
Can't find your answer ? Ask !
August 25, 2011 3:19:23 PM

^Thank you jpishgar and ssddx

Ill add and everything you posted :) 

Edit: ssddx, I added pretty much everything you mention.

Also, about the price of the mid/low entry brands. This is subjective, because I am judging by the entire scale of pricing. There are amplifiers that cost 100 bucks and there are amplifiers that cost in the tens of thousands, some even over a hundred thousand. Same with speakers...the price scale goes into the hundreds of thousands, sometimes millions.

So if you take for example, the Bowers and Wilkins 800D speakers...at $25,000 each, even klipsch's palladium series seems mid to low entry. When you compare to some speakers of Dynaudio where there are speakers retailing at $80,000 each...then klipsch's palladium becomes something more of a joke than actual speakers. So I'm trying to maintain my ratings of low/mid/ high end based on the entire scale.

However, if you want me to shrink my *scale*, I can.
August 30, 2011 5:40:55 PM

My apologies for not getting the pictures up...haven't had power since saturday. Even though my generator is rumbling outside, its providing somewhat unstable voltage and makes my UPS go crazy, so I don't want to damage my main desktop by turning it on. The pictures I edited and have ready are on there. As soon as the real power is back, I'll get some diagrams up for:

Digital/Analog
Surround-Sound Setups
Screenshots of some specifications
And some other stuff that I haven't thought of yet.
August 30, 2011 6:57:07 PM

instead of basing on "entry level", "mid-level" and "high level" you might want to instead either add/replace with "speakers under $xxxxx. this will eliminate any confusion.

i wouldnt want anyone thinking those brands are comparable to the sort of "low end" you might buy in a walmart for $50.

up to you whether you want to shrink the scale or not but i think my suggestion is adequate. keep in mind though that 99%+ of the people posting here aren't going to buy a $100,000 speaker.

September 2, 2011 3:56:45 AM

^Okay, I modified the "Scale"

I also added pictures of specifications of amplifiers and speakers as well as a graph of a analog/digital wave.

Edit: Added driver/equalizer (forgot)

Hurray for Power just coming back!
September 7, 2011 2:16:15 PM

gd post man, u pretty much covered what needs to be known in this forum

but im still tired of answering all the soundcard, maybe u could put that around the pre amp section? or make a computer audio noob section????

jsut some liable suggestions.
September 8, 2011 1:25:29 PM

yeah, adding a section about "computer speakers and soundcards" would be helpful.

at the very least this should be covered:
-photo showing rear ports of soundcard and purpose
-wiring differences between pc speaker connections and home theater speaker connections
-sound over hdmi if supported by video card (for exporting to receivers)
September 8, 2011 7:48:33 PM

My specialty is the science behind how speakers word down to the fundamental electronic levels (plus home theater stuff)...all the connection types, sound cards, computer stuff isn't really my specialty...I understand the general sound-card principle, but i'm not familiar with all the new features so I haven't decided if I'll do one and if I do, it will take a bit while I do some research to make sure I have my facts straight on it.
September 9, 2011 7:59:10 PM

I think a user by the name of gamerk is making a guide on soundcards...not sure though, just what I've heard.
September 13, 2011 8:19:32 PM

I'm going to add a section on electricity now which will include:

-Explanation of parallel vs series wiring
-Impedance vs Resistance
September 13, 2011 11:37:37 PM

nice nice
September 18, 2011 10:45:04 AM

Great advice all over but I think one other crucial part of information is your listening room / home cinema room and the acoustics within. An old/cheap system in a good room sounds better than a new/expensive system in a bad room. I´d suggest you have a peek here:

September 18, 2011 3:31:43 PM

SweetSpot said:
Great advice all over but I think one other crucial part of information is your listening room / home cinema room and the acoustics within. An old/cheap system in a good room sounds better than a new/expensive system in a bad room. I´d suggest you have a peek here:



Good idea, I'll add a section with some information on acoustics :) 
September 18, 2011 3:42:59 PM

Yes, thanks. I certainly think you should. Acoustics is not only a vital subject but compared to buying new hardware also a cheap path to follow. And any investments in acoustics is for life - you do not need upgrades :) 

However, it is a tricky subject with lots of stuff sold that is mainly focused on the office market and sometimes works poorly even there.


Aaah.. my link above looks weird. Will try again:

Sounds of Science sound absorbers
September 18, 2011 9:52:14 PM

^I added the basics on reflections and reverberation. I could add more on bass traps, panels, standing waves...etc...but seeing how its unpopular for people to consider that and its straying outside of the basics range, I don't think we need that. However if you want me to add some more information, I certainly can. Plus I know quite some about acoustics, its not my "specialty" like speakers and amps are, so if I get something a bit wrong, please call me out so I can fix it.
September 19, 2011 4:05:57 AM

Nah, guess it´s good for now, eh, just making sure people know it is an integrated and very important area.
September 24, 2011 3:16:48 AM

I know its "Home" Audio section, but I want to add a small section about car audio that needs to be clarified and some facts/myths. If you want me to take it down, just say so and I will.
September 30, 2011 9:13:27 AM

Nice reading, thanks for the sharing. learn very useful audio tips.
December 12, 2011 8:55:06 AM

Types of speakers: ADD "field coil" (used on tube amp equipment)
December 25, 2011 12:46:12 PM

Could we please start a sub-section to subwoofers about how they connect to a receiver eg line level vs speaker level inputs.

What are the advantages/disadvantages of running your speakers from the receiver via the sub and then out to the speakers?

Many subs have this option although I think higher end subs opt for line level only.

Cheers
December 25, 2011 12:50:04 PM

And perhaps on Phase, 0 Degrees or 180 Degrees (Inverted)

Gracias
June 5, 2012 3:38:52 AM

SweetSpot said:
Yes, thanks. I certainly think you should. Acoustics is not only a vital subject but compared to buying new hardware also a cheap path to follow. And any investments in acoustics is for life - you do not need upgrades :) 

However, it is a tricky subject with lots of stuff sold that is mainly focused on the office market and sometimes works poorly even there.


Aaah.. my link above looks weird. Will try again:

Sounds of Science sound absorbers
few years ago I got my first guitar, a Yamaha Beginner Acoustic FG700. It has served me well
June 8, 2012 11:09:31 PM

I'm going to update the file source section to make it a lot more organized and clear.
June 26, 2012 11:34:23 AM

Making an update on electricity and how it relates to audio.
September 15, 2012 4:57:42 AM

very nice..
September 15, 2012 4:59:43 AM

neways how much time did it take to make this.. :p  great effort
September 25, 2012 11:04:23 PM

Great article, very informative! I had a comment that I wanted to share about my experience with Pioneer's customer service (*hint* it was horrible!) but I also did not want to jack your thread. I felt the lack and poor quality of their service was enough that I would not purchase one of their products again. Just wanted to throw in my 2 cents, I noticed it was listed as a recommended receiver manufacturer ;) .
October 16, 2012 7:26:49 PM

Well, my list is not based on the quality of customer support. Its based on how good quality the receivers and equipment actually is.

Some companies have absolutely phenomenal customer service, but the equipment has horrible quality.
October 16, 2012 7:31:25 PM

Fair enough, I did actually receive a response from a manager and he was very apologetic, somewhat alleviated my concerns, but it was also concerning that my mainboard had to be replaced after 6 months. Audio quality wise I have few complaints but also little to benchmark it against.
March 2, 2013 12:34:41 PM

First of all this was a great read, thanks a ton! Now what I'd like clarified is the SPdif section. I've found so much conflicting information on the subject that I am getting quite the headache. From what I understand it is a 2 channel (stereo) specification. But I have also read that it can and does carry other specifications compressed?

My main reason for this question is that I am trying to hook up a HTPC to a 7.1 receiver and my video is not hdmi. If I connect the hdmi from the video card then the system thinks there is another video stream (unacceptable). If I disable this display then the sound channels are also shut off. :( 

May 3, 2013 7:30:17 PM

ssddx said:
bravo, about time all this information was mentioned in a fairly laid out post.

this should be stickied and referred to/read by people seeking advice to familiarize themselves before asking us questions. a MODERATOR should look at this. [EDIT: looks like it got stickied by the time i finished writing this!!]

keep up the good work.
---

you might want to briefly touch on the differences between "computer audio" and "home theatre audio"

s/pdif should be added to the optical connections listing.

analog connections should be listed, if just briefly

imo hdmi > coax since if you're going to be using one for video anyways.

for brand recommendations the words "budget inclined" give false representation. this leads one to believe they are brands for only people with little money to spend (for example under $500). for example my mid ranged pioneer receiver was $500 and i know they make even higher end models. my klipsh speakers were also around $500 (sub $350) and they are the lower end models. klipsh has sets which are over $10,000. i think you need to clarify this section a bit.

if you place down firing subwoofers on thick carpeting some of the sound will be muffled. to avoid this sometimes people place them on a hard board or other such platform. i've heard that down firing subwoofers are more omnidirectional and spread sound out better than forward firing models.

i agree with the weight comment in terms of audio equipment. i commonly use the reference with computer power supplies as well. a psu weighing 10-15lbs is a good thing (provided you dont try to actually lift your computer case!).

you might want to list a brief section on HTIB (home theatre in a box) solutions.

a small section on speaker placement and why running the "speaker test" to calculate speaker delay is important.

going over 2.1, 5.1, 7.1, multi sub setups: differences, pros, cons, etcetera might be nice.
Excellent and very informative.

June 12, 2013 8:01:08 AM

You mentioned that peak power(headroom) is NOT important. A good amp will be able to deliver peak power without clipping or distortion. maybe we are getting are definitions crossed but I want an amp to put out lets say 1000(or a lot more) watts in a short instant.

Link that better explains it: http://www.enjoythemusic.com/magazine/manufacture/0708/
June 13, 2013 3:01:49 AM

Really very informative post. I saved it for future and bookmared the link.
September 9, 2013 1:31:09 AM

useful information, thanks.
December 1, 2013 9:29:50 AM

Excellent guide! It very much helps that I already have an understanding of video and physics, but overall this is an excellent guide to someone like me who has never familiarized himself with anything related to how audio works.

I have a suggestion though, but bare with me because A.) I'm not finished reading this and B.) it might be difficult for me to explain:

For the layman, the one question that one might ask him/herself is, "well, if digital audio is composed of only dots while analog is continuous, how are these spaces or gaps in digital filled during the conversion from digital to audio?" Personally, I assume that these filled-in gaps in analog are essentially just spots that are devoid of any actual sound that a sound system is producing, and in its place are just background noises from any number of things in nature. Would I be right on that, and if so, if it's not already incorporated into the guide, perhaps it'd be beneficial to implement it as well?
February 28, 2014 5:47:00 AM

thank you useful information
June 19, 2014 5:47:16 PM

Deus Gladiorum said:
Excellent guide! It very much helps that I already have an understanding of video and physics, but overall this is an excellent guide to someone like me who has never familiarized himself with anything related to how audio works.

I have a suggestion though, but bare with me because A.) I'm not finished reading this and B.) it might be difficult for me to explain:

For the layman, the one question that one might ask him/herself is, "well, if digital audio is composed of only dots while analog is continuous, how are these spaces or gaps in digital filled during the conversion from digital to audio?" Personally, I assume that these filled-in gaps in analog are essentially just spots that are devoid of any actual sound that a sound system is producing, and in its place are just background noises from any number of things in nature. Would I be right on that, and if so, if it's not already incorporated into the guide, perhaps it'd be beneficial to implement it as well?


That's a very good question. You are almost right, except that the digital must get converted to alalog or we wouldn't hear it -- the analog being a speaker. when a signal is converted from digital to analog, it really just becomes a string of voltages which are the sum of the digital numbers. the sound is theorhetically just pulses, with space between. What happens in practive, however is that electronics are not perfect, and the conversions take some tie to happen, so that the actual signal curves from from one level to the next, coming out looking very much like the original analog signal that we wanted to hear.
When digital recording first started and CDs became popular, the analog recording techniques were not quite as good as the digital ones, so that CDs sounded 'better' than the old analog. Basically, the OLD analog recording devices, such as magnetic tape, could not do a truly faithful representation of the sound, but only an approximation. In Studio recording the approximation was very good, but some of us oldsters remember cassette tape, which sounded nothing like the original, and it was easy to tell a recording from live performance. (Notwithstanding the old ads "Is it live, or is it Memorex".)Since the advent of digital recording and electronic music, it becomes difficult to tell a well reproduced recording from the original.
less than a minute ago

Long but nice!
!