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November 30, 2004 2:14:12 AM

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

hello!

please, is there any website having complete schematics for speaker
enclosures building? i am interested in transmission line speakers.

thanks,
hrvoje

More about : building speakers

Anonymous
November 30, 2004 6:04:49 AM

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

Also try your post at alt.audio.pro.live-sound

-bg-

--
www.thelittlecanadaheadphoneband.ca
www.lchb.ca
"hrvoje" <horvoje@inet.hr> wrote in message
news:cog6t5$ga4$2@sunce.iskon.hr...
> hello!
>
> please, is there any website having complete schematics for speaker
> enclosures building? i am interested in transmission line speakers.
>
> thanks,
> hrvoje
November 30, 2004 8:16:22 AM

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

On Mon, 29 Nov 2004 23:14:12 +0100, hrvoje <horvoje@inet.hr> wrote:

>hello!
>
>please, is there any website having complete schematics for speaker
>enclosures building? i am interested in transmission line speakers.
>
>thanks,
>hrvoje

Look for books by David B Weems... he makes it simple... I have many
enjoyable years of enclosures deisgned by him.. I built some in the
60s ... and still have them today.

cheers
the islander
Related resources
Anonymous
November 30, 2004 8:16:23 AM

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

"islander" wrote ...

> hrvoje wrote:
>>please, is there any website having complete schematics for speaker
>>enclosures building? i am interested in transmission line speakers.

> Look for books by David B Weems... he makes it simple... I have many
> enjoyable years of enclosures deisgned by him..

And more recently (in the Thiele-Small era) by Vance Dickason.

> I built some in the 60s ... and still have them today.

I had my pair of Weems design boxes for many years. JBL
LE-20 woofer, PR-20 passive radiator, and JBL dome tweeter
and passover. Surrounds on the LE and PR-20 finally crumbled
into dust. I had them re-coned, but they seem a lot stiffer than
the originals. Might have to measure new T-S parameters and
design a new box for them. Old box fell apart, too (cheap
particle board).
Anonymous
November 30, 2004 8:32:12 AM

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

Subscribe to the DIY Speaker list.
To subscribe or unsubscribe via the World Wide Web, visit

http://diyspeakers.net/mailman/listinfo/diyspeakers

Ask away, and you'll more than likely find answer and leads.



Best regards,



John Hallliburton
Anonymous
November 30, 2004 9:29:10 AM

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

**bg** wrote:

> Also try your post at alt.audio.pro.live-sound

For a *transmission line* design !

I don't think so.


Graham
Anonymous
November 30, 2004 11:40:48 AM

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

"hrvoje" <horvoje@inet.hr> wrote in message
news:cog6t5$ga4$2@sunce.iskon.hr

> please, is there any website having complete schematics for speaker
> enclosures building?

Tons of them. Many are actually pretty good You might try searching for them
with google.

> I am interested in transmission line speakers.

Bad, bad idea unless you want to waste materials, time and money.
Anonymous
November 30, 2004 11:40:49 AM

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

>> I am interested in transmission line speakers.

> Bad, bad idea unless you want to waste materials, time and money.


I hope you mean that in terms of making mistakes (which is possible) rather than
in terms of sound quality.

Transmission lines tend to be overdamped. The result is tighter, more-detailed
bass. "High Performance Loudspeakers" states that listeners usually prefer
overdamped bass (which is also achievable in a sealed enclosure), even when the
corner frequency is higher.

Some years back, Bud Fried played his model O transmission line woofer for me at
his home. It was the first time I'd heard a woofer whose transparency, detail,
and lack of coloration were comparable to a good midrange driver.

In theory, this should be achievable from a properly designed sealed box,
assuming the Q is the same and the box is suitably rigid and dead.
Anonymous
November 30, 2004 12:05:53 PM

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

In article <10qo32v9r5k12cf@corp.supernews.com>,
Richard Crowley <rcrowley7@xprt.net> wrote:
>"islander" wrote ...
>
>> hrvoje wrote:
>>>please, is there any website having complete schematics for speaker
>>>enclosures building? i am interested in transmission line speakers.
>
>> Look for books by David B Weems... he makes it simple... I have many
>> enjoyable years of enclosures deisgned by him..
>
>And more recently (in the Thiele-Small era) by Vance Dickason.

I don't think either of these guys really address transmission-line
designs very much, though.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 30, 2004 12:07:14 PM

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

Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
>**bg** wrote:
>
>> Also try your post at alt.audio.pro.live-sound
>
>For a *transmission line* design !
>
>I don't think so.

Actually, that is a good question. Why AREN'T the live sound guys using
transmission line subs? It would seem like a good way to get much deeper
bass, and with some proper vent design even some directionality, out of
small bass cabinets.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 30, 2004 12:07:15 PM

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

> Actually, that is a good question. Why AREN'T the live-sound
> guys using transmission line subs? It would seem like a good
> way to get much deeper bass, and with some proper vent design
> even some directionality, out of small bass cabinets.

Transmission lines generally require large or long cabinets.
Anonymous
November 30, 2004 1:16:37 PM

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

"William Sommerwerck" <williams@nwlink.com> wrote in message
news:10qp05egjtoaud2@corp.supernews.com

>>> I am interested in transmission line speakers.

> Bad, bad idea unless you want to waste materials, time and money.

> I hope you mean that in terms of making mistakes (which is possible)
> rather than in terms of sound quality.

I'm speaking in an engineering sense, which I'm prone to do.

> Transmission lines tend to be overdamped. The result is tighter,
> more-detailed bass. "High Performance Loudspeakers" states that
> listeners usually prefer overdamped bass (which is also achievable in
> a sealed enclosure), even when the corner frequency is higher.

That's all fine and good, particularly if its true.

But, you don't have to waste time, materials, and valuable space in the
listening room to do a TL, if you want an overdamped speaker.
Anonymous
November 30, 2004 1:16:38 PM

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

>> Transmission lines tend to be overdamped. The result is tighter,
>> more-detailed bass. "High Performance Loudspeakers" states that
>> listeners usually prefer overdamped bass (which is also achievable
>> in a sealed enclosure), even when the corner frequency is higher.

> That's all fine and good, particularly if its true.

> But, you don't have to waste time, materials, and valuable space in
> the listening room to do a TL, if you want an overdamped speaker.

Agreed. The question is, does a sealed-box overdamped woofer sound the same as a
transmission line? I don't know the answer.
Anonymous
November 30, 2004 1:21:07 PM

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

http://www.t-linespeakers.org/

It's a fascinating, and often frustrating, project. I'm also interested
in building one; keep me posted. donr@100bain.com

hrvoje wrote:

> hello!
>
> please, is there any website having complete schematics for speaker
> enclosures building? i am interested in transmission line speakers.
>
> thanks,
> hrvoje
Anonymous
November 30, 2004 1:26:45 PM

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

William Sommerwerck <williams@nwlink.com> wrote:
>> Actually, that is a good question. Why AREN'T the live-sound
>> guys using transmission line subs? It would seem like a good
>> way to get much deeper bass, and with some proper vent design
>> even some directionality, out of small bass cabinets.
>
>Transmission lines generally require large or long cabinets.

I thought the big deal was that the cabinet with the folded path was
comparatively much smaller than a huge sealed box with the same resonant
frequency?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 30, 2004 1:26:46 PM

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

>>> Actually, that is a good question. Why AREN'T the live-sound
>>> guys using transmission line subs? It would seem like a good
>>> way to get much deeper bass, and with some proper vent design
>>> even some directionality, out of small bass cabinets.

>> Transmission lines generally require large or long cabinets.

> I thought the big deal was that the cabinet with the folded path was
> comparatively much smaller than a huge sealed box with the same
> resonant frequency?

I don't think so. Look at acoustic-suspension speakers, for example.
Anonymous
November 30, 2004 1:44:36 PM

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

In article <10qp51j49ug8t0a@corp.supernews.com>,
William Sommerwerck <williams@nwlink.com> wrote:
>>> Transmission lines tend to be overdamped. The result is tighter,
>>> more-detailed bass. "High Performance Loudspeakers" states that
>>> listeners usually prefer overdamped bass (which is also achievable
>>> in a sealed enclosure), even when the corner frequency is higher.
>
>> That's all fine and good, particularly if its true.
>
>> But, you don't have to waste time, materials, and valuable space in
>> the listening room to do a TL, if you want an overdamped speaker.
>
>Agreed. The question is, does a sealed-box overdamped woofer sound the same as a
>transmission line? I don't know the answer.

One of the interesting things about the transmission line sub is the
degree of directionality in the radiation pattern.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 30, 2004 1:44:37 PM

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

> One of the interesting things about the transmission line
> sub is the degree of directionality in the radiation pattern.

Bud has been saying that for decades. Do you have any references?
Anonymous
November 30, 2004 1:52:52 PM

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

"Scott Dorsey" <kludge@panix.com> wrote in message
news:coi3fl$lhi$1@panix2.panix.com
> William Sommerwerck <williams@nwlink.com> wrote:
>>> Actually, that is a good question. Why AREN'T the live-sound
>>> guys using transmission line subs? It would seem like a good
>>> way to get much deeper bass, and with some proper vent design
>>> even some directionality, out of small bass cabinets.
>>
>> Transmission lines generally require large or long cabinets.
>
> I thought the big deal was that the cabinet with the folded path was
> comparatively much smaller than a huge sealed box with the same
> resonant frequency?

Not at all.

TL's are kind of interesting because there is no formal definition of what
they are. Depending on how you make them they can be thought of as being
vented boxes with well-damped ports, or sealed boxes (i.e., a really
small-diameter or very short or very long TL).

Every analysis or experimental evaluation I've seen says that you can get at
least the same or more bang for the box volume by just doing a sealed or
vented box, and coming in through the front door as it were.
Anonymous
November 30, 2004 1:52:53 PM

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

> TL's are kind of interesting because there is no formal definition
> of what they are. Depending on how you make them they can be
> thought of as being vented boxes with well-damped ports, or sealed
> boxes (ie, a really small-diameter or very short or very long TL).

> Every analysis or experimental evaluation I've seen says that you
> can get at least the same or more bang for the box volume by just
> doing a sealed or vented box, and coming in through the front door
> as it were.

That's true simply in terms of bass extension. It's not necessarily true in
terms of sound quality. The raison d'etre of transmission lines is that they
"sound better." Clearly, someone should do research comparing sealed boxes and
transmission lines with the same (or similar) Qs, rolloffs, etc.
Anonymous
November 30, 2004 1:53:53 PM

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

"William Sommerwerck" <williams@nwlink.com> wrote in message
news:10qp51j49ug8t0a@corp.supernews.com
>>> Transmission lines tend to be overdamped. The result is tighter,
>>> more-detailed bass. "High Performance Loudspeakers" states that
>>> listeners usually prefer overdamped bass (which is also achievable
>>> in a sealed enclosure), even when the corner frequency is higher.
>
>> That's all fine and good, particularly if its true.
>
>> But, you don't have to waste time, materials, and valuable space in
>> the listening room to do a TL, if you want an overdamped speaker.
>
> Agreed. The question is, does a sealed-box overdamped woofer sound
> the same as a transmission line? I don't know the answer.

That hangs on the question of which actual transmision line you are speaking
of. There are a lot of different things that are called TLs.
Anonymous
November 30, 2004 1:53:54 PM

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

>> Agreed. The question is, does a sealed-box overdamped woofer
>> sound the same as a transmission line? I don't know the answer.

> That hangs on the question of which actual transmision line you are
> speaking of. There are a lot of different things that are called TLs.

I suppose "anything Bud designs" <grin>. Would that be a quarter-wave at the
drivers fundamental resonance, heavily stuffed?

Does anyone remember sulfur hexafluoride (as in William Michael Watson
Dayton-Wright)? In principle, filling the line with sulfur hexafluoride would
permit a significantly shorter line. (By the way, the Dayton-Wright sealed-box
"Watson" woofers were among the best I ever heard.)
Anonymous
November 30, 2004 4:46:53 PM

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

"William Sommerwerck" <williams@nwlink.com> wrote in message
news:10qpfo79s222b8f@corp.supernews.com
>>> Agreed. The question is, does a sealed-box overdamped woofer
>>> sound the same as a transmission line? I don't know the answer.
>
>> That hangs on the question of which actual transmision line you are
>> speaking of. There are a lot of different things that are called TLs.

> I suppose "anything Bud designs" <grin>. Would that be a quarter-wave
> at the drivers fundamental resonance, heavily stuffed?

What is the cross-section of the tube?

> Does anyone remember sulfur hexafluoride (as in William Michael Watson
> Dayton-Wright)?

Yeah, their electrostats, right?

> In principle, filling the line with sulfur
> hexafluoride would permit a significantly shorter line.

I hear tell that heavy stuffing is a effective if less-exotic way to
accomplish a similar end.

>(By the way,
> the Dayton-Wright sealed-box "Watson" woofers were among the best I
> ever heard.)

No comment.
Anonymous
November 30, 2004 4:46:54 PM

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

>> I suppose "anything Bud designs" <grin>. Would that be
>> a quarter-wave at the drivers fundamental resonance,
>> heavily stuffed?

> What is the cross-section of the tube?

Roughly the size of the driver. Not much larger.


>> Does anyone remember sulfur hexafluoride (as in
>> William Michael Watson Dayton-Wright)?

> Yeah, their electrostats, right?

Yes, and some fantastic cone woofers. They got a clean 16Hz that rattled
everything in the room from a two-cubic-foot box.


>> In principle, filling the line with sulfur hexafluoride
>> would permit a significantly shorter line.

> I hear tell that heavy stuffing is an effective if less-exotic way to
> accomplish a similar end.

It does, but the speed of sound in sulfur hexafluoride is significantly slower
than it is in air, so combining the two...
Anonymous
November 30, 2004 5:22:09 PM

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

In article <10qpfges93hbid3@corp.supernews.com>,
William Sommerwerck <williams@nwlink.com> wrote:
>> One of the interesting things about the transmission line
>> sub is the degree of directionality in the radiation pattern.
>
>Bud has been saying that for decades. Do you have any references?

I will see what I can dig up. I think the point is that the vent is very
far away from the main driver acoustically, and so there are all kinds of
interference things going on between them. My suspicion is that this
results in a pattern that changes wildly with frequency too, but I don't
think I have actually seen measurements. Let me poke around in the file
cabinet for a bit.

I think you can get similar directionality with stacked subs, too, and
that is a common technique in the PA world.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 30, 2004 5:22:10 PM

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

>>> One of the interesting things about the transmission line
>>> sub is the degree of directionality in the radiation pattern.

>> Bud has been saying that for decades. Do you have any references?

> I will see what I can dig up. I think the point is that the vent is very
> far away from the main driver acoustically, and so there are all kinds of
> interference things going on between them. My suspicion is that this
> results in a pattern that changes wildly with frequency too, but I don't
> think I have actually seen measurements. Let me poke around in the file
> cabinet for a bit.

One of the theories of TL design is that the rear wave marches down the line and
disappears, with little or nothing coming out the opening. (I don't like calling
it a port, because that implies a fourth-order transfer function.) But as Arny
pointed out, TL design is not well-defined.
Anonymous
November 30, 2004 8:58:26 PM

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

"Scott Dorsey" <kludge@panix.com> wrote in message
news:coi3fl$lhi$1@panix2.panix.com...
> William Sommerwerck <williams@nwlink.com> wrote:
> >> Actually, that is a good question. Why AREN'T the live-sound
> >> guys using transmission line subs? It would seem like a good
> >> way to get much deeper bass, and with some proper vent design
> >> even some directionality, out of small bass cabinets.
> >
> >Transmission lines generally require large or long cabinets.
>
> I thought the big deal was that the cabinet with the folded path was
> comparatively much smaller than a huge sealed box with the same resonant
> frequency?

Well, sealed boxes don't really have a resonant frequency, other than
standing waves if you're not careful. Speakers have resonant frequencies
when mounted in closed boxes, inevitably higher than their free air
resonance frequency. Transmission lines, in theory at least, have the same
equivalent resonance frequency as the free air frequency, which would
require (theoretically) an infinitely large closed box. So yes, you can get
low bass from a transmission line with a smaller (smaller than infinite) box
than a closed box. But typically a vented box is smaller still for an
equivalent bass response, and easier to build, and lighter to carry.
(Although less well-braced than a TL!)

Peace,
Paul
Anonymous
November 30, 2004 9:00:09 PM

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

"Scott Dorsey" <kludge@panix.com> wrote in message
news:cohuo1$96q$1@panix2.panix.com...
> In article <10qo32v9r5k12cf@corp.supernews.com>,
> Richard Crowley <rcrowley7@xprt.net> wrote:
> >"islander" wrote ...
> >
> >> hrvoje wrote:
> >>>please, is there any website having complete schematics for speaker
> >>>enclosures building? i am interested in transmission line speakers.
> >
> >> Look for books by David B Weems... he makes it simple... I have many
> >> enjoyable years of enclosures deisgned by him..
> >
> >And more recently (in the Thiele-Small era) by Vance Dickason.
>
> I don't think either of these guys really address transmission-line
> designs very much, though.

I think Dickason does in his newer editions.

Peace,
Paul
Anonymous
November 30, 2004 10:03:18 PM

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

On Tue, 30 Nov 2004 09:39:55 -0800, "William Sommerwerck"
<williams@nwlink.com> wrote:

>> That hangs on the question of which actual transmision line you are
>> speaking of. There are a lot of different things that are called TLs.
>
>I suppose "anything Bud designs" <grin>. Would that be a quarter-wave at the
>drivers fundamental resonance, heavily stuffed?

This brings up two factors not yet mentioned. The driver's fundamental
resonance is affected by coupling to a considerable air mass in the
line and by the line air's compliance, making the whole model messy.

And, the stuffing reduces the speed of sound in the line, up to as
much as a factor of three.

For homebrewers, transmission lines have a great advantage. A
perfectly good one can be made from a cardboard tube, like a
concrete pouring form. No wood.

Chris Hornbeck
Anonymous
November 30, 2004 10:03:19 PM

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

Chris Hornbeck <chrishornbeckremovethis@att.net> wrote:
>
>For homebrewers, transmission lines have a great advantage. A
>perfectly good one can be made from a cardboard tube, like a
>concrete pouring form. No wood.

You can do vented boxes this way too! Hsu Research does. I think Tannoy
used to do this with some of their installed-sound speakers too.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 30, 2004 10:03:19 PM

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

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in message
news:44gpq0luv6jqjt83a8jg0bjjnu4dqqpe1o@4ax.com
> On Tue, 30 Nov 2004 09:39:55 -0800, "William Sommerwerck"
> <williams@nwlink.com> wrote:
>
>>> That hangs on the question of which actual transmision line you are
>>> speaking of. There are a lot of different things that are called
>>> TLs.
>>
>> I suppose "anything Bud designs" <grin>. Would that be a
>> quarter-wave at the drivers fundamental resonance, heavily stuffed?
>
> This brings up two factors not yet mentioned. The driver's fundamental
> resonance is affected by coupling to a considerable air mass in the
> line and by the line air's compliance, making the whole model messy.

The usually stated solution to that is to *properly* damp the line.

> And, the stuffing reduces the speed of sound in the line, up to as
> much as a factor of three.

It also dissipates energy, resulting in negligable audio output from the end
of the line, perhaps.

> For homebrewers, transmission lines have a great advantage. A
> perfectly good one can be made from a cardboard tube, like a
> concrete pouring form. No wood.

Ditto for ported and unvented enclosures. Seen it done many times.
Anonymous
November 30, 2004 10:03:20 PM

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

"Scott Dorsey" <kludge@panix.com> wrote in message
news:coihcu$aim$1@panix2.panix.com
> Chris Hornbeck <chrishornbeckremovethis@att.net> wrote:
>>
>> For homebrewers, transmission lines have a great advantage. A
>> perfectly good one can be made from a cardboard tube, like a
>> concrete pouring form. No wood.
>
> You can do vented boxes this way too! Hsu Research does. I think
> Tannoy used to do this with some of their installed-sound speakers
> too.

Also, after-market automotive sound.
Anonymous
November 30, 2004 10:24:13 PM

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

Scott Dorsey wrote:

> Pooh Bear <rabbitsfriendsandrelations@hotmail.com> wrote:
> >**bg** wrote:
> >
> >> Also try your post at alt.audio.pro.live-sound
> >
> >For a *transmission line* design !
> >
> >I don't think so.
>
> Actually, that is a good question. Why AREN'T the live sound guys using
> transmission line subs? It would seem like a good way to get much deeper
> bass, and with some proper vent design even some directionality, out of
> small bass cabinets.

Most live sound gear seems currently to be optimised for low weight and
compactness.

This design seems popular with some....

http://www.speakerplans.com/page182.html


Graham
Anonymous
November 30, 2004 10:51:32 PM

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

>
> Actually, that is a good question. Why AREN'T the live sound guys using
> transmission line subs? It would seem like a good way to get much deeper
> bass, and with some proper vent design even some directionality, out of
> small bass cabinets.

They do, it's just a special type, called a horn. ;>)

Best regards,

John
Anonymous
November 30, 2004 10:51:33 PM

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

John Halliburton <j_challiburton@ameritech.net> wrote:
>>
>> Actually, that is a good question. Why AREN'T the live sound guys using
>> transmission line subs? It would seem like a good way to get much deeper
>> bass, and with some proper vent design even some directionality, out of
>> small bass cabinets.
>
>They do, it's just a special type, called a horn. ;>)

Okay, YOU can help me move the Altec X-1s next time.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Anonymous
November 30, 2004 10:57:37 PM

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

>
> That's true simply in terms of bass extension. It's not necessarily true
in
> terms of sound quality. The raison d'etre of transmission lines is that
they
> "sound better." Clearly, someone should do research comparing sealed boxes
and
> transmission lines with the same (or similar) Qs, rolloffs, etc.

The conclusions presented assume that each type of alignment/system is
designed for optimum performance.

In terms of quality, a horn still has the lowest distortion, the best(or
nearly best) impulse response, and the best chance at reproducing a waveform
as presented. There are phase response lags in direct radiator designs that
are nearly impossible to correct, hence many of the sound characteristics we
take for granted in multi bandwidth speaker systems. When you hear
something like a fully horn loaded design, full range electrostatics, nearly
full range ribbons, the sound can be so much more realistic.

Best regards,

John Halliburton
Anonymous
November 30, 2004 10:57:38 PM

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

"John Halliburton" <j_challiburton@ameritech.net> wrote in message
news:Rg4rd.1794$d84.586@newssvr31.news.prodigy.com

> In terms of quality, a horn still has the lowest distortion, the
> best(or nearly best) impulse response, and the best chance at
> reproducing a waveform as presented. There are phase response lags in
> direct radiator designs that are nearly impossible to correct, hence
> many of the sound characteristics we take for granted in multi
> bandwidth speaker systems.

You may have forgotten to mention a very important advantage - directivity
control.

But like so many lunches, none of the advantages come free of serious
practical disadvantages in most environments (other than live sound).

Even in live sound applications, the popularity of linear arrays suggests
that many find that the advantages of waveguides (proper name for what some
people call horns) are outweighed.

> When you hear something like a fully horn
> loaded design, full range electrostatics, nearly full range ribbons,
> the sound can be so much more realistic.

Due to the directivity control issue, waveguides seem to stand alone. The
number of commercial electrostats and ribbons that are capable of operating
effectively in the 20-80 Hz range is vanishingly small.
Anonymous
November 30, 2004 11:48:36 PM

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

William Sommerwerck wrote:

>> Actually, that is a good question. Why AREN'T the live-sound
>> guys using transmission line subs? It would seem like a good
>> way to get much deeper bass, and with some proper vent design
>> even some directionality, out of small bass cabinets.

> Transmission lines generally require large or long cabinets.

I'd prefer to say that actually "doing bass" at high efficiency requires
a large cabinet, whatever the type. Squeeze the box smaller and the cost
is there in terms o loss of efficiency, bandwith, increased distortion
or "all of the above, but more boxes in the same size truck".


Kind regards

Peter Larsen

--
*******************************************
* My site is at: http://www.muyiovatki.dk *
*******************************************
Anonymous
November 30, 2004 11:50:53 PM

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

William Sommerwerck wrote:

> Agreed. The question is, does a sealed-box overdamped woofer sound the same as a
> transmission line? I don't know the answer.

What's overdamped mean technically?

What's a transmission line speaker, again technically?


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
December 1, 2004 12:26:40 AM

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

> Okay, YOU can help me move the Altec X-1s next time.
> --scott

Ungghhhhh.

JHH
Anonymous
December 1, 2004 2:14:00 AM

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

On Tue, 30 Nov 2004 17:38:19 -0500, "Arny Krueger" <arnyk@hotpop.com>
wrote:

>> This brings up two factors not yet mentioned. The driver's fundamental
>> resonance is affected by coupling to a considerable air mass in the
>> line and by the line air's compliance, making the whole model messy.
>
>The usually stated solution to that is to *properly* damp the line.

Yeah, it's often recommended to use higher stuffing density at the
driver end (which I do with mine) and to taper the bore of the line
(which I don't). They are surprisingly tolerant of my poor
modeling ability, and good thing, too.


>> For homebrewers, transmission lines have a great advantage. A
>> perfectly good one can be made from a cardboard tube, like a
>> concrete pouring form. No wood.
>
>Ditto for ported and unvented enclosures. Seen it done many times.

The best woofers I've heard were made with (corian) tubes. They each
had a fancy 18 inch driver in both ends, a small internal volume to
force fundamental resonance above the operating range, and electronic
correction to F-sub-c of 8 Hz and Q-sub-c of 0.5.

Four of these tubes in a home situation was optimum, and the whole
system only cost a little more than my house. Real nice sound though.

Chris Hornbeck
Anonymous
December 1, 2004 2:58:05 AM

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

"William Sommerwerck" williams@nwlink.com wrote:



>>>> One of the interesting things about the transmission line
>>>> sub is the degree of directionality in the radiation pattern.
>
>>> Bud has been saying that for decades. Do you have any references?
>
>> I will see what I can dig up. I think the point is that the vent is very
>> far away from the main driver acoustically, and so there are all kinds of
>> interference things going on between them. My suspicion is that this
>> results in a pattern that changes wildly with frequency too, but I don't
>> think I have actually seen measurements. Let me poke around in the file
>> cabinet for a bit.
>
>One of the theories of TL design is that the rear wave marches down the line
>and
>disappears, with little or nothing coming out the opening. (I don't like
>calling
>it a port, because that implies a fourth-order transfer function.) But as
>Arny
>pointed out, TL design is not well-defined.

If the line is intended to dissipate or absorb the rear radiation of the driver
it would seem that a good one is simply another form of infinite baffle.

My personal subwoofer system uses multiple drivers in a basement loaded IB
system. So when I open the basement door can I call it a Transmission Line?
Anonymous
December 1, 2004 2:58:06 AM

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

> If the line is intended to dissipate or absorb the rear radiation of the
driver
> it would seem that a good one is simply another form of infinite baffle.

True, but I tend to see overdamping as a fundamental element of TL designs,
which is not a part of infinite baffling.


> My personal subwoofer system uses multiple drivers in a basement loaded IB
> system. So when I open the basement door can I call it a Transmission Line?

Only if you stuff the basement with damping material!
Anonymous
December 1, 2004 3:20:41 AM

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

On 30 Nov 2004 23:58:05 GMT, nousaine@aol.com (Nousaine) wrote:

>If the line is intended to dissipate or absorb the rear radiation of the driver
>it would seem that a good one is simply another form of infinite baffle.

That's a good point, but there are slight differences. Coupling to the
appreciable air mass within the line lowers sensitivity below
reference sensitivity (free air). And damping by the shorted
quarter wavelength "stub" can potentially reduce Q-sub-c to
below Q-sub-s, not possible in any (passive/ unassisted) IB.

Neither of these are very large effects, so I'd guess that
you're essentially right.

Chris Hornbeck
Anonymous
December 1, 2004 4:02:56 AM

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

Chris Hornbeck <chrishornbeckremovethis@att.net> wrote:

> A perfectly good one can be made from a cardboard tube, like a
> concrete pouring form.

Yeah, but Bose thought of it and patented it years ago so it's a big
no-no! :) 

Look for their Bose Cannon product.

--
Eric (Dero) Desrochers
http://homepage.mac.com/dero72

Hiroshima 45, Tchernobyl 86, Windows 95
Anonymous
December 1, 2004 8:43:52 AM

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

On Tue, 30 Nov 2004 20:50:53 -0800, Bob Cain
<arcane@arcanemethods.com> wrote:

>What's overdamped mean technically?

Total (transfer/ "acoustic") Q lower than Butterworth.

>What's a transmission line speaker, again technically?

The name comes from RF, and is really abused in the transfer.
"A damped, shorted-quarter-wavelength line" is both less
and more than a useful model. Works anyway; excellent for
homebrewers; hopeless for modeling-wannabe's like moi.

Maybe you could shed some horsepressure?

I can say that the interesting part may turn out to be in the
fibrous tangle. Chaos enters here, so nobody wants to talk about it.

Good fortune,

Chris Hornbeck
Anonymous
December 1, 2004 8:43:53 AM

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

Chris Hornbeck wrote:
> On Tue, 30 Nov 2004 20:50:53 -0800, Bob Cain
> <arcane@arcanemethods.com> wrote:
>
>
>>What's overdamped mean technically?
>
>
> Total (transfer/ "acoustic") Q lower than Butterworth.

Cool. What's the benefit of that?

> The name comes from RF, and is really abused in the transfer.
> "A damped, shorted-quarter-wavelength line" is both less
> and more than a useful model. Works anyway; excellent for
> homebrewers; hopeless for modeling-wannabe's like moi.
>
> Maybe you could shed some horsepressure?

Nah, just raw skepticism.

> I can say that the interesting part may turn out to be in the
> fibrous tangle. Chaos enters here, so nobody wants to talk about it.

That's "fiber bundle". :-)


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein
Anonymous
December 1, 2004 8:58:48 AM

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

Chris Hornbeck wrote:

> On Tue, 30 Nov 2004 20:50:53 -0800, Bob Cain
> <arcane@arcanemethods.com> wrote:
>
> >What's overdamped mean technically?
>
> Total (transfer/ "acoustic") Q lower than Butterworth.
>
> >What's a transmission line speaker, again technically?
>
> The name comes from RF, and is really abused in the transfer.
> "A damped, shorted-quarter-wavelength line" is both less
> and more than a useful model. Works anyway; excellent for
> homebrewers; hopeless for modeling-wannabe's like moi.
>
> Maybe you could shed some horsepressure?
>
> I can say that the interesting part may turn out to be in the
> fibrous tangle. Chaos enters here, so nobody wants to talk about it.

Long haired wool was the fibre of choice IIRC.


Graham
Anonymous
December 1, 2004 9:05:54 AM

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

On Wed, 01 Dec 2004 05:43:52 GMT, Chris Hornbeck
<chrishornbeckremovethis@att.net> wrote:

>Maybe you could shed some horsepressure?

Re-reading this reminds me that there are no W. Shakespeare's
alive today. So, rather than trying, probably equally lamely,
to paraphrase myself, please permit me to control-X the above,
and insert:

I wonder if you'd be interested in exerting a little rigor
into the discussion? The existing models lack rigor, but more
importantly lack a fresh viewpoint.

Rock-n-roll,

Chris Hornbeck
Anonymous
December 1, 2004 9:17:58 AM

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

On Wed, 01 Dec 2004 05:58:48 +0000, Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote:

>Long haired wool was the fibre of choice IIRC.

Excellent! And man-made substitutes have a difficult task
substituting. Real chaos is expensive.

Your point emphasizes for me the lack of mathematical modeling
in "transmission-line" speaker boxes. It's too difficult for
schmoes like me, and too arbitrary for lotsa heavy-math folks.

However, I can see an actual model as being possible, even
if requiring an iterative solution. Similar models are needed
for acoustic horn design, incidentally.

Thanks,

Chris Hornbeck
!