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small room and bass.

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Anonymous
April 19, 2004 9:06:13 AM

Archived from groups: rec.audio.high-end (More info?)

Hi everyone. If i have a small, square 11'x 11' listening room am i doomed to
have no bass? No matter whether i add a subwoofer or two? Can i never get any
better bass than 50hz? -Bob Bernstein.

More about : small room bass

April 19, 2004 7:43:23 PM

Archived from groups: rec.audio.high-end (More info?)

Small spaces are usually good for bass (automobiles for example) but a
square room is not good. I would try a (one) sub woofer and experiment
with location.

-MIKE
Anonymous
April 19, 2004 8:28:24 PM

Archived from groups: rec.audio.high-end (More info?)

The idea that "some rooms are too small for bass" is widespread. It has
something to do with wavelengths and the space required to support specific
frequencies. Lacking any training in physics I have always wondered
wondered how this logic could be true. What if it were applied to
headphones? Given a distance from diaphragm to eardrum of maybe an inch
headphones shouldn't produce bass, or even midrange.
I believe that you can get good bass. A square room can create
problems, but there are solutions. I can refer you to Acoustic Sciences
Corporation, a leader in room treatment.
http://www.acousticsciences.com/ascmain.htm Maybe they have what you need.
Of course there are many other companies in the field and some DIY
solutions, but solutions offered by ASC's experts just might be worth the
money.

Wylie Williams
The Speaker and Stereo Store

"RBernst929" <rbernst929@aol.com> wrote in message
news:c5vmo501eqb@news1.newsguy.com...
> Hi everyone. If i have a small, square 11'x 11' listening room am i
doomed to
> have no bass? No matter whether i add a subwoofer or two? Can i never
get any
> better bass than 50hz? -Bob Bernstein.
Related resources
Anonymous
April 20, 2004 5:28:26 AM

Archived from groups: rec.audio.high-end (More info?)

Subwoofer placement in the room is probably the problem. Many years
ago, I had a friend who used Altec theater systems with a 400 watt
Crown amplifier. He complained about the lack of bass at his
listening position ... which it turned out, was in a null. At other
room locations, the bass levels were so high they were intolerable.

To find your best subwoofer location, first place the subwoofer at
your listening position. Then, while feeding it a low frequency
signal, walk around the room, listening along the walls, at the height
the sub woofer would be, either by ear or with an SPL meter, for the
loudest location. Then relocate your subwoofer to that location, and
you should have the problem solved.

On 19 Apr 2004 05:06:13 GMT, rbernst929@aol.com (RBernst929) wrote:

>Hi everyone. If i have a small, square 11'x 11' listening room am i doomed to
>have no bass? No matter whether i add a subwoofer or two? Can i never get any
>better bass than 50hz? -Bob Bernstein.
Anonymous
April 20, 2004 5:28:39 AM

Archived from groups: rec.audio.high-end (More info?)

Subwoofer placement in the room is probably the problem. Many years
ago, I had a friend who used Altec theater systems with a 400 watt
Crown amplifier. He complained about the lack of bass at his
listening position ... which it turned out, was in a null. At other
room locations, the bass levels were so high they were intolerable.

To find your best subwoofer location, first place the subwoofer at
your listening position. Then, while feeding it a low frequency
signal, walk around the room, listening along the walls, at the height
the sub woofer would be, either by ear or with an SPL meter, for the
loudest location. Then relocate your subwoofer to that location, and
you should have the problem solved.

On 19 Apr 2004 05:06:13 GMT, rbernst929@aol.com (RBernst929) wrote:

>Hi everyone. If i have a small, square 11'x 11' listening room am i doomed to
>have no bass? No matter whether i add a subwoofer or two? Can i never get any
>better bass than 50hz? -Bob Bernstein.
Anonymous
April 20, 2004 6:01:03 AM

Archived from groups: rec.audio.high-end (More info?)

rbernst929@aol.com (RBernst929) wrote in message news:<c5vmo501eqb@news1.newsguy.com>...
> Hi everyone. If i have a small, square 11'x 11' listening room
> am i doomed to have no bass? No matter whether i add a subwoofer
> or two? Can i never get any better bass than 50hz?

This is a common and, to some, and intuitive conclusion. The
assumption is that if you can't fit a wavelength in it, the room
can't support that frequency.

Intuitive as it may seem, it's wrong.

I wrote an extensive article debunking this myth in a recent
AudioExpress issue. Rather than going into that level of detail,
let me summarize the principles and conclusions.

"Sound," as detected by the ear, is the pysiological response to
movement of the eardrum. For the eardrum to move in response to
acoustical stimuli requires a periodic chnage in the difference
in pressure on one side of the eardrum vs the other. This is
germaine to your question, because what is says is simply that
you need a change in pressure of a sufficient amplitude and
within certain frequency limits to hear the sound.

Now, we do not "hear" wavelengths, we hear pressure variations.
So, to perceive a sound, all we have to have is the pressure
variations in the air in the vicinity of our ears, variations,
again, of sufficient pressure and within a certain range of
frequencies in order to hear something.

SO, all the loudspeaker has to do is cause those pressure
variations to happen, That's it. It doesn't make ANY difference
how big the room is. In fact, consider the lowly headphone> if
the "intuitive" conclusion was correct, it would be impossible
for headphones to have ANY information below a few thousand Hz,
being that the size of the "room" they are working into is only
a couple of inches in its largest dimension.

Another example of how it is possible for "bass" to exist in a
very small enclosure is the Bruel & Kjaer pistonphone
calibrator, used for calibratiing microphones. It has a chamber
which is on the order of 3/4" in it's largest dimension,
suggesting a lower limit, using your rule of thumb, of about
9000 Hz. Yet it operates quite nicely at its design frequency of
250 Hz and, in fact, can be slowed down to a few Hz. Above the
frequency where simply air leaks dominate (a fraction of a Hz,
the response of this "room" is essentially flat from about 5-10
Hz to about 800 kHz, where is stops working in pressure mode and
starts working in various resonant exitation modes.

And that's what's happening in your 11' x 11' room. About 50 Hz
is the frequency where HOW the room works changes. At and above
50 Hz, it's operating in various resonant modes. Well above
50Hz, it's essentially operating in a diffuse field mode. Below
50 Hz, it's operatring in pressure mode, down to the frequency
where the room "leaks" (determined by the volume of the room and
the size of the leaks).

But, most assuredly, you can have bass at and well below 50 Hz
in such a room.
Anonymous
April 20, 2004 6:07:03 AM

Archived from groups: rec.audio.high-end (More info?)

rbernst929@aol.com (RBernst929) wrote in message news:<c5vmo501eqb@news1.newsguy.com>...
> Hi everyone. If i have a small, square 11'x 11' listening room am i doomed to
> have no bass? No matter whether i add a subwoofer or two? Can i never get any
> better bass than 50hz? -Bob Bernstein.

well you are limited by the size of your sub speaker and cabinet
a 15" speaker is going to reach lower, a well designed cabinet
can go a whole octive lower. Your sound source is going to determine
some limitations.
locating the sub as close to the floor as possible does increase the
low frequency capibility. Using the right EQ the right way can make a
world of difference, I use EQ fearlessly. but generally a sub makes a huge
difference, you only need one good one in many cases.
Recommend sub with separate amp and electronic crossover, user selectable
crossover point.
a single sub can gain 3 db by sitting in the corner on the floor.
break up the square corners in your room with treatments to avoid
standing waves from the subwoofer.
Anonymous
April 20, 2004 6:08:17 AM

Archived from groups: rec.audio.high-end (More info?)

rbernst929@aol.com (RBernst929) wrote in message news:<c5vmo501eqb@news1.newsguy.com>...
> Hi everyone. If i have a small, square 11'x 11' listening room
> am i doomed to have no bass? No matter whether i add a subwoofer
> or two? Can i never get any better bass than 50hz?

This is a common and, to some, and intuitive conclusion. The
assumption is that if you can't fit a wavelength in it, the room
can't support that frequency.

Intuitive as it may seem, it's wrong.

I wrote an extensive article debunking this myth in a recent
AudioExpress issue. Rather than going into that level of detail,
let me summarize the principles and conclusions.

"Sound," as detected by the ear, is the pysiological response to
movement of the eardrum. For the eardrum to move in response to
acoustical stimuli requires a periodic chnage in the difference
in pressure on one side of the eardrum vs the other. This is
germaine to your question, because what is says is simply that you
need a change in pressure of a sufficient amplitude and within
certain frequency limits to hear the sound.

Now, we do not "hear" wavelengths, we hear pressure variations.
So, to perceive a sound, all we have to have is the pressure
variations in the air in the vicinity of our ears, variations,
again, of sufficient pressure and within a certain range of
frequencies in order to hear something.

SO, all the loudspeaker has to do is cause those pressure variations
to happen, That's it. It doesn't make ANY difference how big the
room is. In fact, consider the lowly headphone> if the "intuitive"
conclusion was correct, it would be impossible for headphones to have
ANY information below a few thousand Hz, being that the size of the
"room" they are working into is only a couple of inches in its largest
dimension.

Another example of how it is possible for "bass" to exist in a very
small enclosure is the Bruel & Kjaer pistonphone calibrator, used for
calibratiing microphones. It has a chamber which is on the order of
3/4" in it's largest dimension, suggesting a lower limit, using your
rule of thumb, of about 9000 Hz. Yet it operates quite nicely at its
design frequency of 250 Hz and, in fact, can be slowed down to a few
Hz. Above the frequency where simply air leaks dominate (a fraction
of a Hz, the response of this "room" is essentially flat from about
5-10 Hz to about 800 kHz, where is stops working in pressure mode
and starts working in various resonant exitation modes.

And that's what's happening in your 11' x 11' room. About 50 Hz is
the frequency where HOW the room works changes. At and above 50 Hz,
it's operating in various resonant modes. Well above 50Hz, it's
essentially operating in a diffuse field mode. Below 50 Hz, it's
operatring in pressure mode, down to the frequency where the room
"leaks" (determined by the volume of the room and the size of the
leaks).

But, most assuredly, you can have bass at and well below 50 Hz in
such a room.
Anonymous
April 20, 2004 6:45:53 AM

Archived from groups: rec.audio.high-end (More info?)

rbernst929@aol.com (RBernst929) wrote:

>
>Hi everyone. If i have a small, square 11'x 11' listening room am i doomed
>to
>have no bass? No matter whether i add a subwoofer or two? Can i never get
>any
>better bass than 50hz? -Bob Bernstein.

You'll get plenty of bass. Below the lowest axial modal frequency (about 50 Hz
in this case) you'll get a 12-dB per octave reinforcement as frequency falls.)
Your biggest probelm is modes stacked at 50 Hz with the ceiling at 70 Hz
(assuming an 8-foot ceiling) and a predominance of energy building up between
50 and 70 Hz.

This is all easily equalizable with even a 1/3 octave equalizer. A single cut
at 50 or 62 Hz will most likely cure things. And you'll have low bass that most
people will just dream of.

The Urban Legend myth that small spaces can't "support" long wavelenght signals
is simply wrong. If it were true then you'd never be able to hear sounds below
about 2000 Hz with closed back headphones.
Anonymous
April 20, 2004 9:12:48 PM

Archived from groups: rec.audio.high-end (More info?)

nousaine@aol.com (Nousaine) wrote in message news:<c622t10cb6@news4.newsguy.com>...
> rbernst929@aol.com (RBernst929) wrote:
>
> >
> >Hi everyone. If i have a small, square 11'x 11' listening room am i doomed
> >to
> >have no bass? No matter whether i add a subwoofer or two? Can i never get
> >any
> >better bass than 50hz? -Bob Bernstein.
>
> You'll get plenty of bass. Below the lowest axial modal frequency
>(about 50 Hz in this case) you'll get a 12-dB per octave reinforce-
> ment as frequency falls.)

Well, no, not exactly. The 12 dB per octave boost occurs because
you're operating the room in pressurization mode from a source
that's operating in constant accelertation mode. The former condition
can only exist of the time constant of the leaks in the room are
significantly longer than the 50 Hz cutoff and the latter exists
in loudspeakers only above fundamental resonance. Violate either
condition, and your 12 dB/octave boost is compromised.
Anonymous
April 21, 2004 12:57:54 AM

Archived from groups: rec.audio.high-end (More info?)

dpierce@cartchunk.org (Dick Pierce) wrote:

>nousaine@aol.com (Nousaine) wrote in message
>news:<c622t10cb6@news4.newsguy.com>...
>> rbernst929@aol.com (RBernst929) wrote:
>>
>> >
>> >Hi everyone. If i have a small, square 11'x 11' listening room am i
>doomed
>> >to
>> >have no bass? No matter whether i add a subwoofer or two? Can i never
>get
>> >any
>> >better bass than 50hz? -Bob Bernstein.
>>
>> You'll get plenty of bass. Below the lowest axial modal frequency
>>(about 50 Hz in this case) you'll get a 12-dB per octave reinforce-
>> ment as frequency falls.)
>
>Well, no, not exactly. The 12 dB per octave boost occurs because
>you're operating the room in pressurization mode from a source
>that's operating in constant accelertation mode. The former condition
>can only exist of the time constant of the leaks in the room are
>significantly longer than the 50 Hz cutoff and the latter exists
>in loudspeakers only above fundamental resonance. Violate either
>condition, and your 12 dB/octave boost is compromised.

This may be true. OTOH in a previous 2150 ft3 room (with only a 5-foot open
doorway) pressure zone reinforcement was clearly evident starting just under 30
Hz. In my Corvette I can measure over 30 dB of reinforcement at 8 Hz with
10-inch woofers in a small sealed enclosures (Fsb 50-60 Hz).
Anonymous
April 21, 2004 4:55:09 AM

Archived from groups: rec.audio.high-end (More info?)

On 4/19/04 1:06 AM, in article c5vmo501eqb@news1.newsguy.com, "RBernst929"
<rbernst929@aol.com> wrote:

> Hi everyone. If i have a small, square 11'x 11' listening room am i doomed to
> have no bass? No matter whether i add a subwoofer or two? Can i never get
> any
> better bass than 50hz? -Bob Bernstein.

You will with that room! The room will boost the bass nicely! Have fun!

(1 sub, moderately powered ought to do it - try a REL 108B)
Anonymous
April 21, 2004 6:52:17 PM

Archived from groups: rec.audio.high-end (More info?)

nousaine@aol.com (Nousaine) wrote in message news:<c622t10cb6@news4.newsguy.com>...

>
> This is all easily equalizable with even a 1/3 octave equalizer. A single cut
> at 50 or 62 Hz will most likely cure things.

....at some position in the room, sure. But 8" to the left, that single
cut @ 50 or 62Hz will have so dramatically skewed the low frequency
response it'll make your head swim when you lean over to pick up your
beer.

You can never completely address temporal artifacts with frequency
adjustments. Peaks & nulls in the low frequency response of small
rooms are due to standing waves & acoustic interference...these are a
direct result of the physical dimensions of your room. Changing the
frequency response of the material you playback into that room does
not change the physical dimensions of the room; there will still be
standing waves at certain frequencies, there will still be peaks &
nulls in the room's response, & you will have simply sacrificed some
valuable amplifier headroom by trying to smooth out those anomalies
with an equalizer. You will also have sacrificed some valuable cash by
buying that equalizer in the first place.

Better to spend that cash on acoustic treatment to smooth out
interference & lessen the effects of room modes. A modest investment
in broadband absorbers & bass traps will do more to flatten the room
response of any playback equipment than even the most expensive
equalizer.
Anonymous
April 21, 2004 8:52:37 PM

Archived from groups: rec.audio.high-end (More info?)

RBernst929 <rbernst929@aol.com> wrote:
> Hi everyone. If i have a small, square 11'x 11' listening room am i doomed to
> have no bass? No matter whether i add a subwoofer or two? Can i never get any
> better bass than 50hz? -Bob Bernstein.

Take a look at the white papers about bass and rooms on the harman web page:
http://www.harman.com/wp/index.jsp?articleId=122
http://www.harman.com/wp/index.jsp?articleId=1003

--
http://www.mat.uc.pt/~rps/

..pt is Portugal| `Whom the gods love die young'-Menander (342-292 BC)
Europe | Villeneuve 50-82, Toivonen 56-86, Senna 60-94
Anonymous
April 21, 2004 8:53:25 PM

Archived from groups: rec.audio.high-end (More info?)

mr_furious@mail.com (Buster Mudd) wrote:



>nousaine@aol.com (Nousaine) wrote in message
>news:<c622t10cb6@news4.newsguy.com>...
>
>>
>> This is all easily equalizable with even a 1/3 octave equalizer. A single
>cut
>> at 50 or 62 Hz will most likely cure things.
>
>...at some position in the room, sure. But 8" to the left, that single
>cut @ 50 or 62Hz will have so dramatically skewed the low frequency
>response it'll make your head swim when you lean over to pick up your
>beer.
>
>You can never completely address temporal artifacts with frequency
>adjustments. Peaks & nulls in the low frequency response of small
>rooms are due to standing waves & acoustic interference...these are a
>direct result of the physical dimensions of your room. Changing the
>frequency response of the material you playback into that room does
>not change the physical dimensions of the room; there will still be
>standing waves at certain frequencies, there will still be peaks &
>nulls in the room's response, & you will have simply sacrificed some
>valuable amplifier headroom by trying to smooth out those anomalies
>with an equalizer. You will also have sacrificed some valuable cash by
>buying that equalizer in the first place.
>
>Better to spend that cash on acoustic treatment to smooth out
>interference & lessen the effects of room modes. A modest investment
>in broadband absorbers & bass traps will do more to flatten the room
>response of any playback equipment than even the most expensive
>equalizer.

It's remarkable that when you get a problem (too much energy in a given
frequency band) that is treatable with a widely available inexpensive device
the old audiophile 'fear of EQ' strikes.

In an 11 X 11 X 8 room there will be too much energy at 50-70 Hz in any of the
better listening/woofer positions (there just aren't that many in a room this
size) because the modal peaks stack up there. I know this because I've response
mapped low frequency performance in 2 of these spaces. It's a job, perhaps one
of a few, perfectly suited for a 1/3 octave EQ.

OTOH I've never seen a case where bass traps have effectively been used to
address such a problem in a room this size. And I don't see that a broadband
absorber would address this problem in any way.

But overall I'd say that the original posters worry that he wouldn't get enough
bass in a small space should certainly have been ameliorated by now.
Anonymous
April 21, 2004 9:39:07 PM

Archived from groups: rec.audio.high-end (More info?)

Buster Mudd <mr_furious@mail.com> wrote:
> nousaine@aol.com (Nousaine) wrote in message news:<c622t10cb6@news4.newsguy.com>...

> >
> > This is all easily equalizable with even a 1/3 octave equalizer. A single cut
> > at 50 or 62 Hz will most likely cure things.

> ...at some position in the room, sure. But 8" to the left, that single
> cut @ 50 or 62Hz will have so dramatically skewed the low frequency
> response it'll make your head swim when you lean over to pick up your
> beer.

Fortunately, I don't do that much leaning over when I'm sitting in
my standard listening position...even after a few beers.

I would bet that most serious audio hobbyists tend
to 1) listen alone and 2) sit in a 'sweet spot' to which their
setup has been tailored. For them, knocking down bass peaks
with EQ has merit.

> You can never completely address temporal artifacts with frequency
> adjustments. Peaks & nulls in the low frequency response of small
> rooms are due to standing waves & acoustic interference...these are a
> direct result of the physical dimensions of your room. Changing the
> frequency response of the material you playback into that room does
> not change the physical dimensions of the room; there will still be
> standing waves at certain frequencies, there will still be peaks &
> nulls in the room's response, & you will have simply sacrificed some
> valuable amplifier headroom by trying to smooth out those anomalies
> with an equalizer. You will also have sacrificed some valuable cash by
> buying that equalizer in the first place.

> Better to spend that cash on acoustic treatment to smooth out
> interference & lessen the effects of room modes. A modest investment
> in broadband absorbers & bass traps will do more to flatten the room
> response of any playback equipment than even the most expensive
> equalizer.

I kinda doubt Tom N. needs a lecture on room acoustics and bass.

--

-S.

"They've got God on their side. All we've got is science and reason."
-- Dawn Hulsey, Talent Director
Anonymous
April 22, 2004 9:35:48 PM

Archived from groups: rec.audio.high-end (More info?)

nousaine@aol.com (Nousaine) wrote in message news:<c668u50ggk@news4.newsguy.com>...
>
> It's remarkable that when you get a problem (too much energy in a given
> frequency band) that is treatable with a widely available inexpensive device
> the old audiophile 'fear of EQ' strikes.
>

'Taint fear; simply common sense: an equalizer is the wrong tool for
the job.

> In an 11 X 11 X 8 room there will be too much energy at 50-70 Hz in any of the
> better listening/woofer positions (there just aren't that many in a room this
> size) because the modal peaks stack up there. I know this because I've response
> mapped low frequency performance in 2 of these spaces.

Cool. I've analyzed 3 such spaces. Between you & me we probably have
just enough data to get any serious acoustician to raise their head
long enough to snort in disgust.

> It's a job, perhaps one
> of a few, perfectly suited for a 1/3 octave EQ.
>

That's a band-aid. You've addressed the symptom, not the problem.
Eliminating the problem passively not only prevents

> OTOH I've never seen a case where bass traps have effectively been used to
> address such a problem in a room this size.

Talk to John Storyk, or Fran Manzella, or Ethan Winer, or Russ
Berger...between just those four esteemed control room designers they
probably have a file of real-world case studies documenting not just
the benefits, but the mandatory need for bass trapping in small
listening rooms.

> And I don't see that a broadband
> absorber would address this problem in any way.
>

By broadband I mean as opposed to a Helmholtz resonator or tuned panel
type absorber, devices which target a specific frequency or narrow
band of frequencies. Broadband absorbers that affect an entire octave
or more would not only tame that excess energy @ 50-70Hz, but would
also address the 102 Hz axial modes that would plague an 11' x 11'
room.

> But overall I'd say that the original posters worry that he wouldn't get enough
> bass in a small space should certainly have been ameliorated by now.

Absolutely!
Anonymous
April 22, 2004 11:58:52 PM

Archived from groups: rec.audio.high-end (More info?)

Oops, hit Send too soon!

nousaine@aol.com (Nousaine) wrote in message news:<c668u50ggk@news4.newsguy.com>...
> It's a job, perhaps one
> of a few, perfectly suited for a 1/3 octave EQ.
>

That's a band-aid. You've addressed the symptom, not the problem.
Eliminating the problem passively not only prevents the symptoms, but
allows you to eliminate a potential source of noise & distortion.
Anonymous
April 23, 2004 1:34:21 AM

Archived from groups: rec.audio.high-end (More info?)

mr_furious@mail.com (Buster Mudd) wrote:

>Oops, hit Send too soon!
>
>nousaine@aol.com (Nousaine) wrote in message
>news:<c668u50ggk@news4.newsguy.com>...
>> It's a job, perhaps one
>> of a few, perfectly suited for a 1/3 octave EQ.
>>
>
>That's a band-aid. You've addressed the symptom, not the problem.
>Eliminating the problem passively not only prevents the symptoms, but
>allows you to eliminate a potential source of noise & distortion.

What you propose is capturing the energy as it is being delivered into the
room. Fine, but its more effective to just reduce the amount of energy into the
room. It is true that traps and absorbers will have some effects on the Q of
room resonances but the fixed Q of a 1/3 octave equalizer seems ready-made for
this particular problem in drywall contruction. And even if it isn't a $300
Symmetrix 552E will give you 5 bands of parametric EQ.

I'm not against mechanical treatments (traps,absorbers) in applications but
they seem too expensive for a simple app like this.
Anonymous
April 24, 2004 6:18:11 PM

Archived from groups: rec.audio.high-end (More info?)

Your best bet is to go with room treatments. There is only oe company that
comes to my mind that can help you out very in expensively. www.roomtune.com
They really can do wonders for your room.
"RBernst929" <rbernst929@aol.com> wrote in message
news:c5vmo501eqb@news1.newsguy.com...
> Hi everyone. If i have a small, square 11'x 11' listening room am i
doomed to
> have no bass? No matter whether i add a subwoofer or two? Can i never
get any
> better bass than 50hz? -Bob Bernstein.
>
Anonymous
April 25, 2004 9:10:27 PM

Archived from groups: rec.audio.high-end (More info?)

In article <kSchc.5788$GR.702891@attbi_s01>,
dpierce@cartchunk.org (Dick Pierce) wrote:

> nousaine@aol.com (Nousaine) wrote in message
> news:<c622t10cb6@news4.newsguy.com>...
> > rbernst929@aol.com (RBernst929) wrote:
> >
> > >
> > >Hi everyone. If i have a small, square 11'x 11' listening room am i
> > >doomed
> > >to
> > >have no bass? No matter whether i add a subwoofer or two? Can i never
> > >get
> > >any
> > >better bass than 50hz? -Bob Bernstein.
> >
> > You'll get plenty of bass. Below the lowest axial modal frequency
> >(about 50 Hz in this case) you'll get a 12-dB per octave reinforce-
> > ment as frequency falls.)
>
> Well, no, not exactly. The 12 dB per octave boost occurs because
> you're operating the room in pressurization mode from a source
> that's operating in constant accelertation mode. The former condition
> can only exist of the time constant of the leaks in the room are
> significantly longer than the 50 Hz cutoff and the latter exists
> in loudspeakers only above fundamental resonance. Violate either
> condition, and your 12 dB/octave boost is compromised.

for acoustic suspension figures doesn't the 12 db/octave boost cancel
the 12 db/octave drop? Leading to the conclusion that one should get a
speaker whose base resonance is just above the room node?
Anonymous
July 2, 2004 4:11:55 AM

Archived from groups: rec.audio.high-end (More info?)

RBernst929 <rbernst929@aol.com> wrote:
> Hi everyone. If i have a small, square 11'x 11' listening room am i doomed to
> have no bass? No matter whether i add a subwoofer or two? Can i never get any
> better bass than 50hz? -Bob Bernstein.

Take a look at:
http://www.harman.com/wp/index.jsp?articleId=122
http://www.harman.com/wp/index.jsp?articleId=1003

--
http://www.mat.uc.pt/~rps/

..pt is Portugal| `Whom the gods love die young'-Menander (342-292 BC)
Europe | Villeneuve 50-82, Toivonen 56-86, Senna 60-94
Anonymous
July 3, 2004 8:50:35 AM

Archived from groups: rec.audio.high-end (More info?)

RBernst929 <rbernst929@aol.com> wrote:

>> Hi everyone. If i have a small, square 11'x 11' listening room am i doomed
>to
>> have no bass? No matter whether i add a subwoofer or two? Can i never get
>any
>> better bass than 50hz? -Bob Bernstein.

The problem you have is too much 50 Hz. If you have an 8-foot ceiling you have
the axial length and width moded stacked up at 50 Hz followed closey with the
ceiling mode at 70 Hz.

But you will get wonderful lower frequency room reinforcement below 50 Hz (12
dB per octave as frequency falls.) However because you have so much at 50 Hz
you just can't appreciate the lower stuff. If you think about how deep your
voice sounds when you sing in the shower you get an idea of how bass works in
small spaces.

The smaller the easier it is to get bass. In a small room however, especially
with identical dimensions things get complicated by the modal range. In yourt
case the modal range starts at 50 Hz and runs to about 300 Hz. In a medium
sized room it usually starts around 30 Hz and runs to 300 Hz.

In a car the modal range is shifted up an octave (60 too 600 Hz) which makes
it easier to get low bass but complicates acoustics in the midrange.
Anonymous
July 3, 2004 11:35:20 AM

Archived from groups: rec.audio.high-end (More info?)

"Rui Pedro Mendes Salgueiro" wrote
>> If i have a small, square 11'x 11' listening room am i doomed to
> > have no bass?

I didn't read your links and I have no training in physics. Nevertheless I
say that if you can have deep bass in the space between a headphone
diaphragm and your eardrum, or in a car, you can have bass in your room. The
size isn't the problem, but the dimensions may be. Have you actually had a
problem or are you just asking?

Wylie Williams
The Speaker and Stereo Store
July 5, 2004 6:39:26 PM

Archived from groups: rec.audio.high-end (More info?)

"Wylie Williams" <wyberwil@earthlink.net> wrote in message news:<YktFc.16946$IQ4.8231@attbi_s02>...
> "Rui Pedro Mendes Salgueiro" wrote
> >> If i have a small, square 11'x 11' listening room am i doomed to
> > > have no bass?
>
> I didn't read your links and I have no training in physics. Nevertheless I
> say that if you can have deep bass in the space between a headphone
> diaphragm and your eardrum, or in a car, you can have bass in your room. The
> size isn't the problem, but the dimensions may be. Have you actually had a
> problem or are you just asking?
>
> Wylie Williams
> The Speaker and Stereo Store

What about medium- and large-sized room? I listen music in a 5.5 * 6
mt with 4.5 mt ceiling. I expect excess bass at around 344/4 = 86 Hz
which i tame with a digital equalizer. Should it be better to dump the
mode with a passive absorber (in principle it it easier to build a
bass absorber at a higher frequency)

Regards
Anonymous
July 8, 2004 8:48:23 PM

Archived from groups: rec.audio.high-end (More info?)

I have no clear idea whether equalizing or absorbing a bass peak is better.
I definitely believe that buying an using a digital equalizer with its
associated microphone would be, for me, more achievable than learning how to
build a bass absorer that would be just right for the frequency and
amplitude of the bass peak. Not that I have used such an equalizer, but I am
considering buying and trying. However, before spending I would like to
hear of some RAHE contributor experiences in this area.

Wylie Williams

"andy" <andyluotto@excite.com> wrote in message
news:yKdGc.28707$Oq2.26503@attbi_s52...
> "Wylie Williams" <wyberwil@earthlink.net> wrote in message
news:<YktFc.16946$IQ4.8231@attbi_s02>...
> > "Rui Pedro Mendes Salgueiro" wrote
> > >> If i have a small, square 11'x 11' listening room am i doomed to
> > > > have no bass?
> >
> > I didn't read your links and I have no training in physics.
Nevertheless I
> > say that if you can have deep bass in the space between a headphone
> > diaphragm and your eardrum, or in a car, you can have bass in your room.
The
> > size isn't the problem, but the dimensions may be. Have you actually had
a
> > problem or are you just asking?
> >
> > Wylie Williams
> > The Speaker and Stereo Store
>
> What about medium- and large-sized room? I listen music in a 5.5 * 6
> mt with 4.5 mt ceiling. I expect excess bass at around 344/4 = 86 Hz
> which i tame with a digital equalizer. Should it be better to dump the
> mode with a passive absorber (in principle it it easier to build a
> bass absorber at a higher frequency)
>
> Regards
>
!