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Mission: Loudspeaker Impossible < 300$

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Anonymous
August 22, 2005 1:40:57 PM

Archived from groups: rec.audio.tech (More info?)

Mission: Loudspeeker Impossible < 300$

I would like to build the ultimate ;o) allround speakers below 300$ with the
following demands.

Usage
# At home.
# Amp 50-70W Std reciever or amp on a best price from Denon, NAD, Cambridge
or alike (normal dynamics)...

Music (and some news)
# Volume: From very low to very high. (high efficiency)
# Characteristics in 3 groups:
Main group, Rock: Springsteen, U2, Cardigans (warm and distinguished)
Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)

Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around
100-160Litres.

1. What kind of basic design is most likely to reach the demands?

2. What other features will improve design at low costs?

....please give your thoughts in the topic.


Morgan O.
Anonymous
August 22, 2005 9:19:56 PM

Archived from groups: rec.audio.tech (More info?)

"Morgan Ohlson" <morgan.ohlson@comhem.se> wrote in message
news:eyuy7mrrca1y$.1x4ps4m5132l7$.dlg@40tude.net...

> Music (and some news)
> # Volume: From very low to very high. (high efficiency)
> # Characteristics in 3 groups:
> Main group, Rock: Springsteen, U2, Cardigans (warm and
distinguished)
> Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
> Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)
>
> Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around
> 100-160Litres.
>
> 1. What kind of basic design is most likely to reach the demands?
>
> 2. What other features will improve design at low costs?

OK; for the music specified, you don't need particularly low frequencies;
down to 40hz is enough.

You don't specify how loud you want the sound level, and what size listening
space.

I suggest a two-way ported speaker with a simple crossover. Use a shelf
port, and tune the enclosure to 35Hz. Line the walls with an inch or so of
wadding. Use an 8-inch bass driver with a resonant frequency below 35Hz,
and an HF driver that can cope with a first-order (6dB/octave) crossover at
3000Hz.

Use 18mm ply for the enclosure, rather than MDF, unless you're experienced
with working with MDF. Plywood costs about three times as much as MDF, but
you will only need one sheet. Paint the enclosures..

I should think you can just about build a pair of reasonable speakers within
your budget, out of a single 8x4 sheet of plywood.

You'll need

Sheet material
Glue
Screws
Speaker clamping kits
Paint
Wadding
Speaker terminals
Crossover components
Internal wire

Estimate the cost of all that, and it will tell you how much you can budget
for the drivers.

I'd suggest looking at Audax drivers; something like the AP210Z0 and
TMO25F1. These drivers will take about half your budget. The bass driver
should be able to handle 40 watts in a 70-litre enclosure tuned to 35Hz,
delivering a sound level of 105dB from 40Hz upwards.

Tim
Anonymous
August 22, 2005 9:23:48 PM

Archived from groups: rec.audio.tech (More info?)

On Mon, 22 Aug 2005 09:40:57 GMT, Morgan Ohlson
<morgan.ohlson@comhem.se> wrote:

>
>Mission: Loudspeeker Impossible < 300$
>
>I would like to build the ultimate ;o) allround speakers below 300$ with the
>following demands.
>
>Usage
># At home.
># Amp 50-70W Std reciever or amp on a best price from Denon, NAD, Cambridge
>or alike (normal dynamics)...
>
>Music (and some news)
># Volume: From very low to very high. (high efficiency)
># Characteristics in 3 groups:
> Main group, Rock: Springsteen, U2, Cardigans (warm and distinguished)
> Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
> Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)
>
>Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around

A square stand may be okay, but for best results no two dimensions
should be the same or have simple ratios (don't make any dimensions
2:1 or 3:2). Each distance from one side to the opposite creates a
standing wave, and making two or more of them the same accentuates
that frequency (and its harmonics) unnecesarily.
This is just one of many details, too much to practically post on
Usenet.

>100-160Litres.
>
>1. What kind of basic design is most likely to reach the demands?
>
>2. What other features will improve design at low costs?

Reading all available books and back issues of "Speaker Builder"
magazine (originally spun off from, then eventually folded back into
Audio Amateur, now Audioxpress).
Is the $300 just on the parts that go into the loudspeaker? (is
this for a pair, or $150 each)? If the $300 is the total you want to
spend, I just blew your budget with reading material.
Oh, now I see your "at low cost" statement. Probably your best bet
is to buy a kit or make a published design in your price range.

>...please give your thoughts in the topic.
>
>
>Morgan O.

-----
http://www.mindspring.com/~benbradley
Related resources
Anonymous
August 22, 2005 10:29:40 PM

Archived from groups: rec.audio.tech (More info?)

On Mon, 22 Aug 2005 17:23:48 GMT, Ben Bradley wrote:

> A square stand may be okay, but for best results no two dimensions
> should be the same or have simple ratios (don't make any dimensions
> 2:1 or 3:2). Each distance from one side to the opposite creates a
> standing wave, and making two or more of them the same accentuates
> that frequency (and its harmonics) unnecesarily.
> This is just one of many details, too much to practically post on
> Usenet.

For which reason you should also never use a circular enclosure, in which
*every* dimension is an identical distance from the centre of the driver.
Diffraction effects are thus magnified manyfold.

d
Anonymous
August 22, 2005 11:36:53 PM

Archived from groups: rec.audio.tech (More info?)

On Mon, 22 Aug 2005 18:29:40 +0100, Don Pearce <donald@pearce.uk.com>
wrote:

>On Mon, 22 Aug 2005 17:23:48 GMT, Ben Bradley wrote:
>
>> A square stand may be okay, but for best results no two dimensions
>> should be the same or have simple ratios (don't make any dimensions
>> 2:1 or 3:2). Each distance from one side to the opposite creates a
>> standing wave, and making two or more of them the same accentuates
>> that frequency (and its harmonics) unnecesarily.
>> This is just one of many details, too much to practically post on
>> Usenet.
>
>For which reason you should also never use a circular enclosure, in which
>*every* dimension is an identical distance from the centre of the driver.
>Diffraction effects are thus magnified manyfold.

Not a problem - you mount the driver in the *side* of the cylinder,
not the end. The JR149 was a classic 'LS3/5a' style speaker with
excellent diffraction and very low cabinet resonance.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
August 23, 2005 12:48:45 AM

Archived from groups: rec.audio.tech (More info?)

On Mon, 22 Aug 2005 19:36:53 +0000 (UTC), Stewart Pinkerton wrote:

> On Mon, 22 Aug 2005 18:29:40 +0100, Don Pearce <donald@pearce.uk.com>
> wrote:
>
>>On Mon, 22 Aug 2005 17:23:48 GMT, Ben Bradley wrote:
>>
>>> A square stand may be okay, but for best results no two dimensions
>>> should be the same or have simple ratios (don't make any dimensions
>>> 2:1 or 3:2). Each distance from one side to the opposite creates a
>>> standing wave, and making two or more of them the same accentuates
>>> that frequency (and its harmonics) unnecesarily.
>>> This is just one of many details, too much to practically post on
>>> Usenet.
>>
>>For which reason you should also never use a circular enclosure, in which
>>*every* dimension is an identical distance from the centre of the driver.
>>Diffraction effects are thus magnified manyfold.
>
> Not a problem - you mount the driver in the *side* of the cylinder,
> not the end. The JR149 was a classic 'LS3/5a' style speaker with
> excellent diffraction and very low cabinet resonance.

True, but mechanically that just feels all wrong.

d
Anonymous
August 23, 2005 1:48:44 AM

Archived from groups: rec.audio.tech (More info?)

On Mon, 22 Aug 2005 17:23:48 GMT, Ben Bradley wrote:

> On Mon, 22 Aug 2005 09:40:57 GMT, Morgan Ohlson
> <morgan.ohlson@comhem.se> wrote:
>
>>
>>Mission: Loudspeeker Impossible < 300$
>>
>>I would like to build the ultimate ;o) allround speakers below 300$ with the
>>following demands.
>>
>>Usage
>># At home.
>># Amp 50-70W Std reciever or amp on a best price from Denon, NAD, Cambridge
>>or alike (normal dynamics)...
>>
>>Music (and some news)
>># Volume: From very low to very high. (high efficiency)
>># Characteristics in 3 groups:
>> Main group, Rock: Springsteen, U2, Cardigans (warm and distinguished)
>> Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
>> Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)
>>
>>Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around
>
> A square stand may be okay, but for best results no two dimensions
> should be the same or have simple ratios (don't make any dimensions
> 2:1 or 3:2). Each distance from one side to the opposite creates a
> standing wave, and making two or more of them the same accentuates
> that frequency (and its harmonics) unnecesarily.
> This is just one of many details, too much to practically post on
> Usenet.
>
>>100-160Litres.
>>
>>1. What kind of basic design is most likely to reach the demands?
>>
>>2. What other features will improve design at low costs?
>
> Reading all available books and back issues of "Speaker Builder"
> magazine (originally spun off from, then eventually folded back into
> Audio Amateur, now Audioxpress).
> Is the $300 just on the parts that go into the loudspeaker? (is
> this for a pair, or $150 each)? If the $300 is the total you want to
> spend, I just blew your budget with reading material.
> Oh, now I see your "at low cost" statement. Probably your best bet
> is to buy a kit or make a published design in your price range.

Small room 20-30m2

One of the issues is also to go for a 2 way system (like 1x1" + 1x8") with
mid priced high value drivers ...

....or use really low priced drivers (high value) to make something like
(1x1" + 1x5" + 2x10") as for lower hifi but more bang!

Alt. 1x1" + 4x6"


Morgan O.
Anonymous
August 23, 2005 2:35:52 AM

Archived from groups: rec.audio.tech (More info?)

Don Pearce wrote:
>>>For which reason you should also never use a circular enclosure, in which
>>>*every* dimension is an identical distance from the centre of the driver.

A college friend of mine came up with a deliberately weird design which
had its mid-range speaker firing down into a tubular column and thence
into a diffusing cone at the bottom. It sounded terrifyingly decent for
such an odd beast. I'm sure he, or someone, has patented it by now
unless there were flaws I wasn't hearing.
Anonymous
August 23, 2005 10:00:41 AM

Archived from groups: rec.audio.tech (More info?)

On Mon, 22 Aug 2005 22:35:52 -0400, Joe Kesselman
<keshlam-nospam@comcast.net> wrote:

>Don Pearce wrote:
>>>>For which reason you should also never use a circular enclosure, in which
>>>>*every* dimension is an identical distance from the centre of the driver.
>
>A college friend of mine came up with a deliberately weird design which
>had its mid-range speaker firing down into a tubular column and thence
>into a diffusing cone at the bottom. It sounded terrifyingly decent for
>such an odd beast. I'm sure he, or someone, has patented it by now
>unless there were flaws I wasn't hearing.

That was a classic design from the '60s, designed IIRC by Gilbert
Briggs of Wharfedale. It used a concrete sewer pipe! Technica produced
similar multiway designs in the '70s, and it's not dissimilar to the
'acoustic lens' used by B&O in their latest Lab 5 design.

--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
August 23, 2005 12:37:41 PM

Archived from groups: rec.audio.tech (More info?)

"Tim Martin" <tim2718281@ntlworld.com> writes:

> "Morgan Ohlson" <morgan.ohlson@comhem.se> wrote in message
> news:eyuy7mrrca1y$.1x4ps4m5132l7$.dlg@40tude.net...
>
> > Music (and some news)
> > # Volume: From very low to very high. (high efficiency)
<snip>
>
> Use 18mm ply for the enclosure, rather than MDF, unless you're experienced
> with working with MDF. Plywood costs about three times as much as MDF, but
> you will only need one sheet. Paint the enclosures..
>
<snip>
What's the matter with MDF?

--
========================================================================
Martin Schöön <Martin.Schoon@gmail.com>

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
========================================================================
Anonymous
August 23, 2005 3:23:37 PM

Archived from groups: rec.audio.tech (More info?)

"Schöön Martin" <Martin.Schoon@dont.spam.ericsson.com> wrote in message
news:s5zfyt15fbe.fsf@dont.spam.ericsson.com...

> What's the matter with MDF?

There's nothing the matter with it - modern MDF is no longer carcinogenic -
but you need better dust-extraction equipment to work with it, you need to
wear a dust mask, and in my experience it takes longer and costs more to get
a decent paint finish on MDF than on plywood.

Tim
Anonymous
August 23, 2005 4:30:43 PM

Archived from groups: rec.audio.tech (More info?)

On Tue, 23 Aug 2005 11:23:37 GMT, Tim Martin wrote:

> "Schöön Martin" <Martin.Schoon@dont.spam.ericsson.com> wrote in message
> news:s5zfyt15fbe.fsf@dont.spam.ericsson.com...
>
>> What's the matter with MDF?
>
> There's nothing the matter with it - modern MDF is no longer carcinogenic -
> but you need better dust-extraction equipment to work with it, you need to
> wear a dust mask, and in my experience it takes longer and costs more to get
> a decent paint finish on MDF than on plywood.
>
> Tim

Order MDF in exact sizes

Drape cabinett with wallpaper or alike...


Morgan O.
Anonymous
August 23, 2005 4:33:08 PM

Archived from groups: rec.audio.tech (More info?)

On Mon, 22 Aug 2005 17:19:56 GMT, Tim Martin wrote:

> "Morgan Ohlson" <morgan.ohlson@comhem.se> wrote in message
> news:eyuy7mrrca1y$.1x4ps4m5132l7$.dlg@40tude.net...
>
>> Music (and some news)
>> # Volume: From very low to very high. (high efficiency)
>> # Characteristics in 3 groups:
>> Main group, Rock: Springsteen, U2, Cardigans (warm and
> distinguished)
>> Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
>> Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)
>>
>> Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around
>> 100-160Litres.
>>
>> 1. What kind of basic design is most likely to reach the demands?
>>
>> 2. What other features will improve design at low costs?
>
> OK; for the music specified, you don't need particularly low frequencies;
> down to 40hz is enough.
>
> You don't specify how loud you want the sound level, and what size listening
> space.
>
> I suggest a two-way ported speaker with a simple crossover. Use a shelf
> port, and tune the enclosure to 35Hz. Line the walls with an inch or so of
> wadding. Use an 8-inch bass driver with a resonant frequency below 35Hz,
> and an HF driver that can cope with a first-order (6dB/octave) crossover at
> 3000Hz.
>
> Use 18mm ply for the enclosure, rather than MDF, unless you're experienced
> with working with MDF. Plywood costs about three times as much as MDF, but
> you will only need one sheet. Paint the enclosures..
>
> I should think you can just about build a pair of reasonable speakers within
> your budget, out of a single 8x4 sheet of plywood.
>
> You'll need
>
> Sheet material
> Glue
> Screws
> Speaker clamping kits
> Paint
> Wadding
> Speaker terminals
> Crossover components
> Internal wire
>
> Estimate the cost of all that, and it will tell you how much you can budget
> for the drivers.
>
> I'd suggest looking at Audax drivers; something like the AP210Z0 and
> TMO25F1. These drivers will take about half your budget. The bass driver
> should be able to handle 40 watts in a 70-litre enclosure tuned to 35Hz,
> delivering a sound level of 105dB from 40Hz upwards.
>
> Tim

Small room 20-30m2

One of the issues is also to go for a 2 way system (like 1x1" + 1x8") with
mid priced high value drivers ...

....or use really low priced drivers (high value) to make something like
(1x1" + 1x5" + 2x10") as for lower hifi but more bang!

Alt. 1x1" + 4x6"


Morgan O.
Anonymous
August 23, 2005 7:49:22 PM

Archived from groups: rec.audio.tech (More info?)

"Morgan Ohlson" <morgan.ohlson@comhem.se> wrote in message
news:11lmbx862kizq$.156z4z9bekhm2.dlg@40tude.net...

> Order MDF in exact sizes

Sure you can, though I suspect you'll end up trimming it anyway, and you'll
probably have to make your own circular holes. Still, it's no big deal.
I've used both; plywood's nicer to work with, but MDF is cheaper.

I think the cost round here would be about $20 for an 8x4 sheet of 18mm MDF,
compared with about $60 for an 8x4 sheet of decent 13-ply 18mm plywood.
Cutting costs are the same for both. So the MDF is clearly cheaper. As
long as you're happy working with it, don't mind the extra weight, and don't
intend to use the speakers outdoors where they could get wet, it's probably
a good choice.

Tim
Anonymous
August 23, 2005 8:25:58 PM

Archived from groups: rec.audio.tech (More info?)

>There's nothing the matter with it - modern MDF is no longer carcinogenic -
>but you need better dust-extraction equipment to work with it, you need to
>wear a dust mask, and in my experience it takes longer and costs more to get
>a decent paint finish on MDF than on plywood.

MDF also eats high-speed-steel saw blades and router bits for lunch.
They go dull quite quickly. It's a good idea (for both cost and
safety reasons) to invest in a decent set of carbide-tipped blades and
bits if you're going to be cutting/shaping a significant amount of MDF.

On the other hand, plywood can present some surprises when used for
loudspeaker cabinets, too, unless you're careful. Some commercial
plywood can have voids in the inner layers, which may become visible
at the edges if you cut through the sheet in just the right (or wrong)
place. in some cases they may even have spots in which the laminates
aren't glued properly, and I've heard people report that this can
occasionally lead to buzzing at high volume levels. Speaker builders
seem to recommend using "void-free marine-grade" plywood to avoid
these problems... it's higher-quality than standard construction-grade
plywood. "Baltic birch" is sometimes suggested.

Plywood may also require a bit more work at the cabinet edges - you
can't easily route it to a smoothly rounded corner, as you can with
MDF, and it may require more filling with wood dough or putty to
present a clean edge for painting.

For subwoofers, cabinet stiffness seems to be of more significance
than the acoustic "deadness" of the wall material - a stiff cabinet
wall can raise the wall's lowest resonant frequency well above the
highest frequency at which the woofer operates. In this application,
plywood seems to have an advantage over MDF.

I built my own (full-range three-way) systems out of MDF,
double-thickness front bezel, with internal cross-braces, and a sheet
of plywood on the bottom to prevent the cabinet's weight from chipping
the bottom edges. Worked out very nicely, but $DEITY are they heavy!

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
August 23, 2005 10:39:08 PM

Archived from groups: rec.audio.tech (More info?)

<<<MDF also eats high-speed-steel saw blades and router bits for
lunch.>>>

Very few people use HSS saw blades anymore, and I haven't seen a HSS
router bit for sale in years. My very well equiped woodshop has
neither in its inventory of tools.
Anonymous
August 24, 2005 1:31:43 AM

Archived from groups: rec.audio.tech (More info?)

On Tue, 23 Aug 2005 16:25:58 +0000, Dave Platt wrote:

>>There's nothing the matter with it - modern MDF is no longer carcinogenic -
>>but you need better dust-extraction equipment to work with it, you need to
>>wear a dust mask, and in my experience it takes longer and costs more to get
>>a decent paint finish on MDF than on plywood.
>
> MDF also eats high-speed-steel saw blades and router bits for lunch.
> They go dull quite quickly. It's a good idea (for both cost and
> safety reasons) to invest in a decent set of carbide-tipped blades and
> bits if you're going to be cutting/shaping a significant amount of MDF.
>
Sounds like a completely different MDF than the material I built plugs
for dagger boards and rudder blades from 20 years ago. That MDF was the
most benign and well mannered material I had ever come across.

<snip>

/Martin
Anonymous
August 24, 2005 1:31:44 AM

Archived from groups: rec.audio.tech (More info?)

In article <pan.2005.08.23.19.31.40.409667@gmail.com>,
Martin Schöön <martin.schoon@gmail.com> wrote:

>> MDF also eats high-speed-steel saw blades and router bits for lunch.
>> They go dull quite quickly. It's a good idea (for both cost and
>> safety reasons) to invest in a decent set of carbide-tipped blades and
>> bits if you're going to be cutting/shaping a significant amount of MDF.
>>
>Sounds like a completely different MDF than the material I built plugs
>for dagger boards and rudder blades from 20 years ago. That MDF was the
>most benign and well mannered material I had ever come across.

I'm told that it's the glue in the MDF, which binds the fibers
together, that's responsible for the rapid wearing of steel blades and
bits. Possibly they've changed the glue formulation over the years.

I believe that the older MDF used a urea-formaldehyde binder, which
is now in disfavor due to the possible health risks of outgassed
formaldehyde. Different resins are used in low-formaldehyde and
formaldehyde-free MDFs such as Medite (tm), and it's possible that
these have a different level of abrasiveness.

I do like MDF for making speaker cabinets - it tends to cut smoothly,
sands and finishes easily, drills easily (although its screw-holding
strength isn't as good as hardwood). However, as with most things,
it's important to use the right tools to do the job, and from
firsthand experience I can say that carbide-tipped tools are better
suited than high-speed-steel ones.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
Anonymous
August 24, 2005 1:42:17 PM

Archived from groups: rec.audio.tech (More info?)

"Morgan Ohlson" <morgan.ohlson@comhem.se> wrote in message
news:eyuy7mrrca1y$.1x4ps4m5132l7$.dlg@40tude.net...
>
> Mission: Loudspeeker Impossible < 300$
>
> I would like to build the ultimate ;o) allround speakers below 300$

Question: Is that $300 each or $300 for the pair? If $300 each, this is
pretty easy. If $300 for the pair, there's a lot more trading off to be
done.

> with the
> following demands.
>
> Usage
> # At home.
> # Amp 50-70W Std receiver or amp on a best price from Denon, NAD,
> Cambridge
> or alike (normal dynamics)...

Are these receivers rock solid stable and happy with 4 ohm loads? Denon
(back in the day) didn't much care for 4 ohms. NAD had no problems with 4
ohms at all. Cambridge I have no experience with.

> Music (and some news)
> # Volume: From very low to very high. (high efficiency)
> # Characteristics in 3 groups:
> Main group, Rock: Springsteen, U2, Cardigans (warm and distinguished)
> Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
> Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)
>
> Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around
> 100-160Litres.

100-160 liters is quite the box.

> 1. What kind of basic design is most likely to reach the demands?

Two or three way system (three way if you're looking at 300 each/600 for the
pair) using 8 or 10 inch woofers.

> 2. What other features will improve design at low costs?

Careful attention to the crossover.

> ...please give your thoughts in the topic.

Quick and dirty two way with deep bass...

Grab a pair of Peerless 4 ohm 10" CC lines (model 831759, 7.5mm linear Xmax)
quick before they're gone. That's 120 bucks. Throw 'em in a 45 liter cabinet
(that includes the expected overvolume for drivers, braces and vent
displacement) tuned to 30 Hz for a QB3 F3 of around 35 Hz and F10 of 25 Hz.
(Same cabinet tuned to 24-25 Hz for roughly BB4 and F3 of around 39 Hz
and an F10 around 23 Hz.) Use an impedance compensation in the woofer
circuit. Add a .25-.30 mH coil in series. That will combine with the woofer
rolloff and the impedance compensation to give you a third order slope at
around 2.3-2.5Khz and kill a breakup mode that shows up above 10KHz. (The
831759 drops at 12db/octave in the octave above 2KHz and is 6 db down around
2.5KHz.) The fly in the ointment is a rough quarter octave wide 5-6db
jog/dip in response between roughly 750-1KHz.

Add a decent tweeter. I'm gonna suggest the Vifa HT26TG-35-06 horn loaded
dome. That's another sixty bucks for a pair. It has a natural 6db high pass
rolloff from around 2.5KHz. Add a second order electrical filter centered at
around 2.3-2.5Khz for a third order slope. You'll need to pad four to five
db out of the tweeter (96 db with 2.83v) to match the Peerless (91 db with
2.83v) woofer. If you use a 1-2 ohm series resistor bypassed with around
1-1.5uF in the tweeter circuit, you can ameliorate a db or two of the
falloff above 17Khz with the Vifa. (If you're over the age of 30, don't
bother. Odds are that you can't hear anything up there anyway.)

You've now got 180 dollars into drivers, the recipe for cheap 6db/12db (18db
acoustic slope) xover that shouldn't be expensive to build (less than ten or
twenty dollars in parts if you don't buy circuit boards) and a hundred bucks
or so left for input cups, binding posts, grills and to build the cabinets
to get a pretty kickass 300 dollar/pair set of speakers that will shake the
walls (figure 106db+ in room for the pair at 34Hz -- 109 db from 40 Hz up --
with 70 watts/peak), handle plenty of power, play plenty loud and still
sound good when played not so loud. Dispersion isn't really a problem with
the woofer (effective cone diameter is around 7.9 inches and the tweeter
will give fill in the half octave below cutoff) and the tweeter is sitting
fat and happy because you've padded 4-5 db power out of the circuit.

If you're into 300/each instead of 300/pair, add a good midrange to the
equation and slice the woofer dip from 750-1Khz out of the equation.

You might consider the 8 ohm version (831727, 9mm linear Xmax) of the same
woofer in a 70 liter box (overvolume for drivers, braces and ports included)
tuned to around 26-27 Hz (QB3) for an F3 of around 28Hz (F10 around 21Hz).
Same box tuned to 22-23 Hz for a BB4 alignment gives an F3 around 32 Hz (F10
at about 20hz) and a "drier" or "tighter" bass. F6 for both tunings crosses
around 25 Hz. Sensitivity drops to 88db/2.83v so you can pad the tweeter
even more. Regardless of the 4 ohm or 8 ohm woofer version, think "Large
Advent" or "ADS L-620" on steroids.

I believe all of these drivers are on the way out. Grab 'em while you can if
this sort of design interests you. The crossover ideas above come from the
back of a napkin. If you can stand the juice, pay someone to model them for
you. If you decide to go three way, definitely pay someone (Madisound?) to
model the crossovers and maybe even suggest a compatible midrange driver.
I'm partial to domes but good ones aren't cheap and aren't easy to find
these days. Regardless of what MR you choose for a three way system, you'll
have to get a driver with a base sensitivity a db or two above the woofer to
account for the crossover insertion loss. Short version: Three ways get
complicated in a hurry.
Anonymous
August 24, 2005 1:44:54 PM

Archived from groups: rec.audio.tech (More info?)

"Oxford Systems" <oxfordsystems@earthlinkdot.net> wrote in message
news:ZhXOe.1222$z2.1051@newsread3.news.pas.earthlink.net...
> "Morgan Ohlson" <morgan.ohlson@comhem.se> wrote in message
> news:eyuy7mrrca1y$.1x4ps4m5132l7$.dlg@40tude.net...
>>
>> Mission: Loudspeeker Impossible < 300$
>>
>> I would like to build the ultimate ;o) allround speakers below 300$
>
> Question: Is that $300 each or $300 for the pair? If $300 each, this is
> pretty easy. If $300 for the pair, there's a lot more trading off to be
> done.
>
>> with the
>> following demands.
>>
>> Usage
>> # At home.
>> # Amp 50-70W Std receiver or amp on a best price from Denon, NAD,
>> Cambridge
>> or alike (normal dynamics)...
>
> Are these receivers rock solid stable and happy with 4 ohm loads? Denon
> (back in the day) didn't much care for 4 ohms. NAD had no problems with 4
> ohms at all. Cambridge I have no experience with.
>
>> Music (and some news)
>> # Volume: From very low to very high. (high efficiency)
>> # Characteristics in 3 groups:
>> Main group, Rock: Springsteen, U2, Cardigans (warm and
>> distinguished)
>> Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
>> Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)
>>
>> Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around
>> 100-160Litres.
>
> 100-160 liters is quite the box.
>
>> 1. What kind of basic design is most likely to reach the demands?
>
> Two or three way system (three way if you're looking at 300 each/600 for
> the
> pair) using 8 or 10 inch woofers.
>
>> 2. What other features will improve design at low costs?
>
> Careful attention to the crossover.
>
>> ...please give your thoughts in the topic.
>
> Quick and dirty two way with deep bass...
>
> Grab a pair of Peerless 4 ohm 10" CC lines (model 831759, 7.5mm linear
> Xmax)
> quick before they're gone. That's 120 bucks. Throw 'em in a 45 liter
> cabinet
> (that includes the expected overvolume for drivers, braces and vent
> displacement) tuned to 30 Hz for a QB3 F3 of around 35 Hz and F10 of 25
> Hz.
> (Same cabinet tuned to 24-25 Hz for roughly BB4 and F3 of around 39 Hz
> and an F10 around 23 Hz.) Use an impedance compensation in the woofer
> circuit. Add a .25-.30 mH coil in series. That will combine with the
> woofer
> rolloff and the impedance compensation to give you a third order slope at
> around 2.3-2.5Khz and kill a breakup mode that shows up above 10KHz. (The
> 831759 drops at 12db/octave in the octave above 2KHz and is 6 db down
> around
> 2.5KHz.) The fly in the ointment is a rough quarter octave wide 5-6db
> jog/dip in response between roughly 750-1KHz.
>
> Add a decent tweeter. I'm gonna suggest the Vifa HT26TG-35-06 horn loaded
> dome. That's another sixty bucks for a pair. It has a natural 6db high
> pass
> rolloff from around 2.5KHz. Add a second order electrical filter centered
> at
> around 2.3-2.5Khz for a third order slope. You'll need to pad four to five
> db out of the tweeter (96 db with 2.83v) to match the Peerless (91 db with
> 2.83v) woofer. If you use a 1-2 ohm series resistor bypassed with around
> 1-1.5uF in the tweeter circuit, you can ameliorate a db or two of the
> falloff above 17Khz with the Vifa. (If you're over the age of 30, don't
> bother. Odds are that you can't hear anything up there anyway.)
>
> You've now got 180 dollars into drivers, the recipe for cheap 6db/12db
> (18db
> acoustic slope) xover that shouldn't be expensive to build (less than ten
> or
> twenty dollars in parts if you don't buy circuit boards) and a hundred
> bucks
> or so left for input cups, binding posts, grills and to build the cabinets
> to get a pretty kickass 300 dollar/pair set of speakers that will shake
> the
> walls (figure 106db+ in room for the pair at 34Hz -- 109 db from 40 Hz
> up --
> with 70 watts/peak), handle plenty of power, play plenty loud and still
> sound good when played not so loud. Dispersion isn't really a problem with
> the woofer (effective cone diameter is around 7.9 inches and the tweeter
> will give fill in the half octave below cutoff) and the tweeter is sitting
> fat and happy because you've padded 4-5 db power out of the circuit.
>
> If you're into 300/each instead of 300/pair, add a good midrange to the
> equation and slice the woofer dip from 750-1Khz out of the equation.
>
> You might consider the 8 ohm version (831727, 9mm linear Xmax) of the same
> woofer in a 70 liter box (overvolume for drivers, braces and ports
> included)
> tuned to around 26-27 Hz (QB3) for an F3 of around 28Hz (F10 around 21Hz).
> Same box tuned to 22-23 Hz for a BB4 alignment gives an F3 around 32 Hz
> (F10
> at about 20hz) and a "drier" or "tighter" bass. F6 for both tunings
> crosses
> around 25 Hz. Sensitivity drops to 88db/2.83v so you can pad the tweeter
> even more. Regardless of the 4 ohm or 8 ohm woofer version, think "Large
> Advent" or "ADS L-620" on steroids.
>
> I believe all of these drivers are on the way out. Grab 'em while you can
> if
> this sort of design interests you. The crossover ideas above come from the
> back of a napkin. If you can stand the juice, pay someone to model them
> for
> you. If you decide to go three way, definitely pay someone (Madisound?) to
> model the crossovers and maybe even suggest a compatible midrange driver.
> I'm partial to domes but good ones aren't cheap and aren't easy to find
> these days. Regardless of what MR you choose for a three way system,
> you'll
> have to get a driver with a base sensitivity a db or two above the woofer
> to
> account for the crossover insertion loss. Short version: Three ways get
> complicated in a hurry.

Know what? I just realized that I'm a little too sleepy/tipsy to be doing
math. Either check the numbers above or ignore 'em completely until I am
awake enough to go over 'em. The basic idea for a 10 inch 2 way is sound but
I'm not at all sure that my rough calcs are correct.
Anonymous
August 24, 2005 2:46:52 PM

Archived from groups: rec.audio.tech (More info?)

"Dave Platt" <dplatt@radagast.org> wrote in message
news:11gmjgmgu7pkn15@corp.supernews.com...

> On the other hand, plywood can present some surprises when used for
> loudspeaker cabinets, too, unless you're careful. Some commercial
> plywood can have voids in the inner layers, which may become visible
> at the edges if you cut through the sheet in just the right (or wrong)
> place. in some cases they may even have spots in which the laminates
> aren't glued properly, and I've heard people report that this can
> occasionally lead to buzzing at high volume levels. Speaker builders
> seem to recommend using "void-free marine-grade" plywood to avoid
> these problems... it's higher-quality than standard construction-grade
> plywood. "Baltic birch" is sometimes suggested.

I think it's the "13-ply" 18mm plywood that's the key. Some 18mm plywood
seems to have three thick centre layers, with two thin outer layers. It's a
lot cheaper than 13-ply - mid way betweeb MDF and 13-ply.

Tim
Anonymous
August 28, 2005 8:19:55 PM

Archived from groups: rec.audio.tech (More info?)

On Wed, 24 Aug 2005 09:44:54 GMT, Oxford Systems wrote:

> "Oxford Systems" <oxfordsystems@earthlinkdot.net> wrote in message
> news:ZhXOe.1222$z2.1051@newsread3.news.pas.earthlink.net...
>> "Morgan Ohlson" <morgan.ohlson@comhem.se> wrote in message
>> news:eyuy7mrrca1y$.1x4ps4m5132l7$.dlg@40tude.net...
>>>
>>> Mission: Loudspeeker Impossible < 300$
>>>
>>> I would like to build the ultimate ;o) allround speakers below 300$
>>
>> Question: Is that $300 each or $300 for the pair? If $300 each, this is
>> pretty easy. If $300 for the pair, there's a lot more trading off to be
>> done.
>>
>>> with the
>>> following demands.
>>>
>>> Usage
>>> # At home.
>>> # Amp 50-70W Std receiver or amp on a best price from Denon, NAD,
>>> Cambridge
>>> or alike (normal dynamics)...
>>
>> Are these receivers rock solid stable and happy with 4 ohm loads? Denon
>> (back in the day) didn't much care for 4 ohms. NAD had no problems with 4
>> ohms at all. Cambridge I have no experience with.
>>
>>> Music (and some news)
>>> # Volume: From very low to very high. (high efficiency)
>>> # Characteristics in 3 groups:
>>> Main group, Rock: Springsteen, U2, Cardigans (warm and
>>> distinguished)
>>> Secondary Acoustic: Vivaldi flute conserto, Al diMeola (much HiFi)
>>> Secondary Rough: Rammstein, Leftfield, Ossy (Low dist. & full base)
>>>
>>> Floor (or low pod) standing box (base 0,3 - 0,4m in square) volume around
>>> 100-160Litres.
>>
>> 100-160 liters is quite the box.
>>
>>> 1. What kind of basic design is most likely to reach the demands?
>>
>> Two or three way system (three way if you're looking at 300 each/600 for
>> the
>> pair) using 8 or 10 inch woofers.
>>
>>> 2. What other features will improve design at low costs?
>>
>> Careful attention to the crossover.
>>
>>> ...please give your thoughts in the topic.
>>
>> Quick and dirty two way with deep bass...
>>
>> Grab a pair of Peerless 4 ohm 10" CC lines (model 831759, 7.5mm linear
>> Xmax)
>> quick before they're gone. That's 120 bucks. Throw 'em in a 45 liter
>> cabinet
>> (that includes the expected overvolume for drivers, braces and vent
>> displacement) tuned to 30 Hz for a QB3 F3 of around 35 Hz and F10 of 25
>> Hz.
>> (Same cabinet tuned to 24-25 Hz for roughly BB4 and F3 of around 39 Hz
>> and an F10 around 23 Hz.) Use an impedance compensation in the woofer
>> circuit. Add a .25-.30 mH coil in series. That will combine with the
>> woofer
>> rolloff and the impedance compensation to give you a third order slope at
>> around 2.3-2.5Khz and kill a breakup mode that shows up above 10KHz. (The
>> 831759 drops at 12db/octave in the octave above 2KHz and is 6 db down
>> around
>> 2.5KHz.) The fly in the ointment is a rough quarter octave wide 5-6db
>> jog/dip in response between roughly 750-1KHz.
>>
>> Add a decent tweeter. I'm gonna suggest the Vifa HT26TG-35-06 horn loaded
>> dome. That's another sixty bucks for a pair. It has a natural 6db high
>> pass
>> rolloff from around 2.5KHz. Add a second order electrical filter centered
>> at
>> around 2.3-2.5Khz for a third order slope. You'll need to pad four to five
>> db out of the tweeter (96 db with 2.83v) to match the Peerless (91 db with
>> 2.83v) woofer. If you use a 1-2 ohm series resistor bypassed with around
>> 1-1.5uF in the tweeter circuit, you can ameliorate a db or two of the
>> falloff above 17Khz with the Vifa. (If you're over the age of 30, don't
>> bother. Odds are that you can't hear anything up there anyway.)
>>
>> You've now got 180 dollars into drivers, the recipe for cheap 6db/12db
>> (18db
>> acoustic slope) xover that shouldn't be expensive to build (less than ten
>> or
>> twenty dollars in parts if you don't buy circuit boards) and a hundred
>> bucks
>> or so left for input cups, binding posts, grills and to build the cabinets
>> to get a pretty kickass 300 dollar/pair set of speakers that will shake
>> the
>> walls (figure 106db+ in room for the pair at 34Hz -- 109 db from 40 Hz
>> up --
>> with 70 watts/peak), handle plenty of power, play plenty loud and still
>> sound good when played not so loud. Dispersion isn't really a problem with
>> the woofer (effective cone diameter is around 7.9 inches and the tweeter
>> will give fill in the half octave below cutoff) and the tweeter is sitting
>> fat and happy because you've padded 4-5 db power out of the circuit.
>>
>> If you're into 300/each instead of 300/pair, add a good midrange to the
>> equation and slice the woofer dip from 750-1Khz out of the equation.
>>
>> You might consider the 8 ohm version (831727, 9mm linear Xmax) of the same
>> woofer in a 70 liter box (overvolume for drivers, braces and ports
>> included)
>> tuned to around 26-27 Hz (QB3) for an F3 of around 28Hz (F10 around 21Hz).
>> Same box tuned to 22-23 Hz for a BB4 alignment gives an F3 around 32 Hz
>> (F10
>> at about 20hz) and a "drier" or "tighter" bass. F6 for both tunings
>> crosses
>> around 25 Hz. Sensitivity drops to 88db/2.83v so you can pad the tweeter
>> even more. Regardless of the 4 ohm or 8 ohm woofer version, think "Large
>> Advent" or "ADS L-620" on steroids.
>>
>> I believe all of these drivers are on the way out. Grab 'em while you can
>> if
>> this sort of design interests you. The crossover ideas above come from the
>> back of a napkin. If you can stand the juice, pay someone to model them
>> for
>> you. If you decide to go three way, definitely pay someone (Madisound?) to
>> model the crossovers and maybe even suggest a compatible midrange driver.
>> I'm partial to domes but good ones aren't cheap and aren't easy to find
>> these days. Regardless of what MR you choose for a three way system,
>> you'll
>> have to get a driver with a base sensitivity a db or two above the woofer
>> to
>> account for the crossover insertion loss. Short version: Three ways get
>> complicated in a hurry.
>
> Know what? I just realized that I'm a little too sleepy/tipsy to be doing
> math. Either check the numbers above or ignore 'em completely until I am
> awake enough to go over 'em. The basic idea for a 10 inch 2 way is sound but
> I'm not at all sure that my rough calcs are correct.

Excuse me for not notising that this new headline was a serious answer to my
Q.

First, the aim is at 300$ a pair (+box)

What do you say about using 2x 10" each... Idea is that two cheap drivers
get reactive and lower.

Many developers seem to willingly use woofers with a sensitivity ~5-7dB
above the midrange driver. What would be proper for an allround speaker?

Morgan O.
August 30, 2005 7:32:33 PM

Archived from groups: rec.audio.tech (More info?)

That's baltic birch plywood (the 13 ply). It comes in 5x5 sheets, so
be prepared to deal with the transportation issues when you go to
pickup a sheet. Most places will cut it for you. Standard birch
plywood, most of which I've seen is from CA, can be found at most home
centers, while Baltic Birch is harder to find. I get it at a local
lumber mill. Baltic birch is generally free of voids, unlike the issue
wiht standard stuff pointed out by Dave.
Anonymous
September 13, 2005 9:42:40 PM

Archived from groups: rec.audio.tech (More info?)

Morgan Ohlson <morgan.ohlson@comhem.se> wrote:
>
>Mission: Loudspeeker Impossible < 300$
>
>I would like to build the ultimate ;o) allround speakers below 300$ with the
>following demands. ...

Get a pair of Infinity Primus 150 speakers (around $125 per pair) and
use their drivers, crossovers and ports. Build stiffer cabinets. Add a
subwoofer if you think that you need it.

It's unlikely that you could do better on your own.

--
Len Moskowitz PDAudio, Binaural Mics, Cables, DPA, M-Audio
Core Sound http://www.stealthmicrophones.com
Teaneck, New Jersey USA http://www.core-sound.com
moskowit@core-sound.com Tel: 201-801-0812, FAX: 201-801-0912
!