[James Lehman]

http://www.akrobiz.com/speakers/new/

This is one of the projects I have had in the works for quite some time now.
I've had a hard time working on them because my ankle has been really
screwed up since I had a surgery on it in April.

They are not done yet, but they are fully functional. There are a lot of
cosmetic issues that need to be finished. These things are impossible to
move without scratching and smashing them up. So I figure I'll get them
looking as good as I can and then finish them in place.

There are three pieces on each side; (1) 36 element fullrange and (2) 4
element subwoofers. You can only see half of the 8 inch woofers. There are
just as many cones facing into the insides of the boxes, as each box
contains a dual isobaric pair.

The line array is 8 ohms. The (2) subwoofers are each 8 ohms, wired in
parallel for a system of 4 ohms. I am using the Behringer 24dB/oct. active
crossover at about 120Hz.

I used my own software and a sound card to measure all of the T/S parameters
of the (4) woofers assembled into a single unit. I used the same software to
tune the ports within the boxes at exactly the right frequency (22.5Hz) to
make the system respond to -3dB at 18Hz.

There are no passive crossover components in this system at all; just
speaker wire and speakers.

James. )

[Kevin McMurtrie]

In article ,
"James Lehman" wrote:

http://www.akrobiz.com/speakers/new/

This is one of the projects I have had in the works for quite some time now.
I've had a hard time working on them because my ankle has been really
screwed up since I had a surgery on it in April.

They are not done yet, but they are fully functional. There are a lot of
cosmetic issues that need to be finished. These things are impossible to
move without scratching and smashing them up. So I figure I'll get them
looking as good as I can and then finish them in place.

There are three pieces on each side; (1) 36 element fullrange and (2) 4
element subwoofers. You can only see half of the 8 inch woofers. There are
just as many cones facing into the insides of the boxes, as each box
contains a dual isobaric pair.

The line array is 8 ohms. The (2) subwoofers are each 8 ohms, wired in
parallel for a system of 4 ohms. I am using the Behringer 24dB/oct. active
crossover at about 120Hz.

I used my own software and a sound card to measure all of the T/S parameters
of the (4) woofers assembled into a single unit. I used the same software to
tune the ports within the boxes at exactly the right frequency (22.5Hz) to
make the system respond to -3dB at 18Hz.

There are no passive crossover components in this system at all; just
speaker wire and speakers.

James. )

Impressive, but it's going to create very complex acoustic interference
patterns. That can sound anywhere from good to bad and there won't be
much you can do to change what you get.

[James Lehman]

Impressive, but it's going to create very complex acoustic interference
patterns. That can sound anywhere from good to bad and there won't be
much you can do to change what you get.

That "interference pattern" you speak of is called a line source array. It
is exactly the effect I was looking for!

James. )

[TonyP]

James Lehman wrote:

http://www.akrobiz.com/speakers/new/

This is one of the projects I have had in the works for quite some time now.
I've had a hard time working on them because my ankle has been really
screwed up since I had a surgery on it in April.

They are not done yet, but they are fully functional. There are a lot of
cosmetic issues that need to be finished. These things are impossible to
move without scratching and smashing them up. So I figure I'll get them
looking as good as I can and then finish them in place.

There are three pieces on each side; (1) 36 element fullrange and (2) 4
element subwoofers. You can only see half of the 8 inch woofers. There are
just as many cones facing into the insides of the boxes, as each box
contains a dual isobaric pair.

The line array is 8 ohms. The (2) subwoofers are each 8 ohms, wired in
parallel for a system of 4 ohms. I am using the Behringer 24dB/oct. active
crossover at about 120Hz.

I used my own software and a sound card to measure all of the T/S parameters
of the (4) woofers assembled into a single unit. I used the same software to
tune the ports within the boxes at exactly the right frequency (22.5Hz) to
make the system respond to -3dB at 18Hz.

There are no passive crossover components in this system at all; just
speaker wire and speakers.

How do they sound? Cost of building?

[James Lehman]

James Lehman wrote:

http://www.akrobiz.com/speakers/new/

This is one of the projects I have had in the works for quite some time
now.


How do they sound? Cost of building?


If you want to read a more active thread about these speakers, look he
http://fullrangedriver.com/forum/viewtopic.php?id=938

If you don't want to join the fullrange forum, then please continue posting
your comments here in rec.audio.tech.

The little TV speakers were the impetus of this design. I got a really
goooood deal on about a thousand of them. They were found pretty much at
random and as-is, take-it-or-leave-it. I don't think I could have picked a
better speaker for this application. They are paper, but there's no reason
to believe that they won't last a very long time. There is NO foam other
than the front gasket, which is not in use. The rolled edge is treated
cloth. I didn't get any technical specs with these drivers at all. But,
judging from the specs I could find of other similar drivers, I would guess
that these have four layer voice coils with a lot of overhang. They are
definitely high excursion, fullrange drivers. They handle a lot of power for
being slightly over 1/2" coils. They were designed to be used as single mono
units in table top TVs or as single units in pairs for computer speakers.
While testing them for this design, I set up a pair of them (one per side)
in decent sized, sealed enclosures and they rocked! They have a Qts (0.7,
1.0) and a low end roll-off that make them ideal in an infinite baffle
application; like a guitar amp speaker or a car speaker. I knew the line was
going to be spectacular even before I ever made it. Since there are 36
drivers in each line, that's like doubling the output of one speaker 5
times! (2 to the 5th = 32). The acoustic coupling effect is awesome. These
speakers are very sensitive.

The subs are a variation and improvement on a design I did about 11 years
ago:
http://www.akrobiz.com/james/estie1.html

These subs use exactly the same model of woofer, but this time the boxes are
about 6.4 cu. ft.. A different isobaric arrangement puts the woofers back to
back, so the cone motion is symmetrical with phase; and there is no passive
crossover.

James. )

[GregS]

In article , "James Lehman" wrote:
James Lehman wrote:

http://www.akrobiz.com/speakers/new/

This is one of the projects I have had in the works for quite some time
now.


How do they sound? Cost of building?


If you want to read a more active thread about these speakers, look he
http://fullrangedriver.com/forum/viewtopic.php?id=938

If you don't want to join the fullrange forum, then please continue posting
your comments here in rec.audio.tech.

The little TV speakers were the impetus of this design. I got a really
goooood deal on about a thousand of them. They were found pretty much at
random and as-is, take-it-or-leave-it. I don't think I could have picked a
better speaker for this application. They are paper, but there's no reason

Reminds me of some of the boxes I have bought. Sometimes you run into something good.
I just wonderd why you just didn't stack them vertically and not use as many, for horzontal dispersion.
Perhaps it would just complicat the lower frequencies, and require another driver stage. When
I use different drivers, I frequently coat the surrounds, and even sometimes caost
all or part of the cones, with either Airflex 400, silicone, or
some other rubbery material. I usually prefer the sound I get when I do this rather than the untreated
driver.

greg

[James Lehman]

Reminds me of some of the boxes I have bought. Sometimes you run into
something good.
I just wonderd why you just didn't stack them vertically and not use as
many, for horzontal dispersion.
Perhaps it would just complicat the lower frequencies, and require another
driver stage. When
I use different drivers, I frequently coat the surrounds, and even
sometimes caost
all or part of the cones, with either Airflex 400, silicone, or
some other rubbery material. I usually prefer the sound I get when I do
this rather than the untreated
driver.

greg

I wanted the voice coils to be as close together as possible. With a line
source array, (theoretically) there is very little vertical dispersion. It's
all about the horizontal. The wide baffle also plays a role in directing the
sound from the front of the line only; effectively, it is a wall. I did not
want to add any mass to the cone. There is no need to lower the Fs. I have
subs. I would't want to reduce the SPL or the high end output.

James. )

[Geoff]

GregS wrote:

I just wonderd why you just didn't stack them vertically and not use
as many, for horzontal dispersion.

No doubt about it - these speakers are huge and have beautiful woodgrain.
Pity they are not approaching a point-source for good imaging !

geoff

[James Lehman]

"Geoff" wrote in message
...
GregS wrote:

I just wonderd why you just didn't stack them vertically and not use
as many, for horzontal dispersion.

No doubt about it - these speakers are huge and have beautiful woodgrain.
Pity they are not approaching a point-source for good imaging !

geoff



Good imaging !!! ???
Ugh!
Some people just don't get it.

http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

James. )

[Geoff]

James Lehman wrote:
"Geoff" wrote in message
...
GregS wrote:

I just wonderd why you just didn't stack them vertically and not use
as many, for horzontal dispersion.

No doubt about it - these speakers are huge and have beautiful
woodgrain. Pity they are not approaching a point-source for good
imaging !

geoff



Good imaging !!! ???
Ugh!
Some people just don't get it.

http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

James. )

Aren't those the tweeters on the adjacent side to the woofers, which
presumably go up to directional frequencies ? Rather than on the same
plane, as near as poss to the woofers ?

geoff

[Kevin McMurtrie]

In article ,
"James Lehman" wrote:

Impressive, but it's going to create very complex acoustic interference
patterns. That can sound anywhere from good to bad and there won't be
much you can do to change what you get.

That "interference pattern" you speak of is called a line source array. It
is exactly the effect I was looking for!

James. )

In theory. The mechanics of the cone and the spaces between the
speakers are deviations from an ideal cylindrical radiation. I'd never
build two speakers at once because I don't trust the details to sound
good

[James Lehman]

Aren't those the tweeters on the adjacent side to the woofers, which
presumably go up to directional frequencies ? Rather than on the same
plane, as near as poss to the woofers ?

geoff



Well, I wouldn't call them tweeters. They are crossed over actively at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the other side
of the room and it would hardly matter.

James. )

[Rudi Fischer]

"James Lehman" wrote:

[...]
Well, I wouldn't call them tweeters. They are crossed over actively at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the other side
of the room and it would hardly matter.

Wrong.
340/120/4 - delta90°@71cm

Did you ever consider why there's the need
for a phase control/-switch on sub(amp)s?

Rudi Fischer
--
....and may good music always be with you

[James Lehman]

"Rudi Fischer" wrote in message
...

"James Lehman" wrote:

[...]
Well, I wouldn't call them tweeters. They are crossed over actively at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the other
side
of the room and it would hardly matter.

Wrong.
340/120/4 - delta90°@71cm

Did you ever consider why there's the need
for a phase control/-switch on sub(amp)s?

Rudi Fischer
--
...and may good music always be with you


"Need" ? I would call it more of an easy feature. It's just as easy to flip
the wires. Consider the fact that a woofer's reactance makes its apparent
acoustic position different than its actual physical position. Also consider
that phase is really only critical at the crossover point. With 24dB/oct.
that issue is, at least, minimized. The coils in my fullrange drivers are
about 45cm away from the coils in the woofers.

James. )

[GregS]

In article , "James Lehman" wrote:

"Rudi Fischer" wrote in message
. ..

"James Lehman" wrote:

[...]
Well, I wouldn't call them tweeters. They are crossed over actively at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the other
side
of the room and it would hardly matter.

Wrong.
340/120/4 - delta90°@71cm

Did you ever consider why there's the need
for a phase control/-switch on sub(amp)s?

Rudi Fischer
--
...and may good music always be with you


"Need" ? I would call it more of an easy feature. It's just as easy to flip
the wires. Consider the fact that a woofer's reactance makes its apparent
acoustic position different than its actual physical position. Also consider
that phase is really only critical at the crossover point. With 24dB/oct.
that issue is, at least, minimized. The coils in my fullrange drivers are
about 45cm away from the coils in the woofers.

I have crossed over to as high as 500 hz with some vertical spacing of at
least 3 feet. 70 Hz seems the accepted frequency where you can't tell
the direction if its a pure sine wave. The mids are crossed over at 120 in my truck
with little directionality of the back woofer. I do hear it a bit in the back sometimes.


greg

[Geoff]

James Lehman wrote:
Aren't those the tweeters on the adjacent side to the woofers, which
presumably go up to directional frequencies ? Rather than on the
same plane, as near as poss to the woofers ?

geoff



Well, I wouldn't call them tweeters. They are crossed over actively at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the
other side of the room and it would hardly matter.


120Hz ?!! Ever wondered why everybody can tell which corner of the room a
Bose sub is in ?

geoff

[James Lehman]

"Geoff" wrote in message
news
James Lehman wrote:
Aren't those the tweeters on the adjacent side to the woofers, which
presumably go up to directional frequencies ? Rather than on the
same plane, as near as poss to the woofers ?

geoff



Well, I wouldn't call them tweeters. They are crossed over actively at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the
other side of the room and it would hardly matter.


120Hz ?!! Ever wondered why everybody can tell which corner of the room a
Bose sub is in ?

geoff



Yes, yes, yes. As I said before... "The coils in my fullrange drivers are
about 45cm away from the coils in the woofers." Bid deal!

James. )

[Rudi Fischer]

"James Lehman" wrote:
"Rudi Fischer" wrote:
"James Lehman" wrote:

[...]
Well, I wouldn't call them tweeters. They are crossed over actively at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the other
side of the room and it would hardly matter.
Wrong.
340/120/4 - delta90°@71cm
Did you ever consider why there's the need
for a phase control/-switch on sub(amp)s?
"Need" ? I would call it more of an easy feature. It's just as easy to flip
the wires.

On active subs (NF-cables)?

Consider the fact that a woofer's reactance makes its apparent
acoustic position different than its actual physical position. Also
consider that phase is really only critical at the crossover point.

Wrong

With 24dB/oct.
that issue is, at least, minimized.

Wrong

Rudi Fischer
--
....and may good music always be with you

[James Lehman]

"Rudi Fischer" wrote in message
...

"James Lehman" wrote:
"Rudi Fischer" wrote:
"James Lehman" wrote:

[...]
Well, I wouldn't call them tweeters. They are crossed over actively
at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the
other
side of the room and it would hardly matter.
Wrong.
340/120/4 - delta90°@71cm
Did you ever consider why there's the need
for a phase control/-switch on sub(amp)s?
"Need" ? I would call it more of an easy feature. It's just as easy to
flip
the wires.

On active subs (NF-cables)?

Consider the fact that a woofer's reactance makes its apparent
acoustic position different than its actual physical position. Also
consider that phase is really only critical at the crossover point.

Wrong

With 24dB/oct.
that issue is, at least, minimized.

Wrong

Rudi Fischer
--
...and may good music always be with you


You've never heard them or seen them, but you know more about them than I
do. Amazing.

They're not fully active subs. They are bi-amped. The amp is sitting in the
stack with all of my other stuff.

The Behringer xover allows me to sweep the center freq from 44 to 930Hz,
continuous, just by twisting a knob. Doing this tell me a lot about the
phase relationship and the relative volume of both of the elements.

James. )

[Rudi Fischer]

"James Lehman" wrote:
"Rudi Fischer" wrote:
"James Lehman" wrote:
"Rudi Fischer" wrote:
"James Lehman" wrote:

[...]
Well, I wouldn't call them tweeters. They are crossed over actively
at
120Hz, 24dB/oct. At that wavelength, the woofers could be on the
other side of the room and it would hardly matter.
Wrong.
340/120/4 - delta90°@71cm
Did you ever consider why there's the need
for a phase control/-switch on sub(amp)s?
"Need" ? I would call it more of an easy feature. It's just as easy to
flip the wires.
On active subs (NF-cables)?
Consider the fact that a woofer's reactance makes its apparent
acoustic position different than its actual physical position. Also
consider that phase is really only critical at the crossover point.
Wrong
With 24dB/oct.
that issue is, at least, minimized.
Wrong
You've never heard them or seen them, but you know more about
them than I do. Amazing.

I truely believe that I'm not the only one
around (this ng).

They're not fully active subs. They are bi-amped. The amp is
sitting in the stack with all of my other stuff.

??
I (very obviously) wasn't referring to /your/ speakers
- and neither were you! You made some very absolute
and general statements and these are plain wrong.
(And actually you'd know this if you'd only read the
beginners book by Dickason...)

The Behringer xover allows me to sweep the center freq from 44 to 930Hz,
continuous, just by twisting a knob.

Do tell...
In fact I can touch a DCX2496 right now.

Doing this tell me a lot about the
phase relationship and the relative volume of both of the elements.

- There's an _acoustic_ HP in you're *fullrange*-unit.
It's possible to (nearly) compensate (especially in
such an array, Mr. Linkwitz comes to mind...), but
you stated you didn't use _any_ equalization.

- You _know_ you're dealing with non-coincidental
drivers and think you can simply ignore it?

This may(!) work out well at /one/ point in
/one/ room (-yours) - but elsewhere?

So I'll clap my hands twice:

1. Nice woodwork!
2. Great courage!;-)

Rudi Fischer
--
....and may good music always be with you

[James Lehman]

- There's an _acoustic_ HP in you're *fullrange*-unit.
It's possible to (nearly) compensate (especially in
such an array, Mr. Linkwitz comes to mind...), but
you stated you didn't use _any_ equalization.

- You _know_ you're dealing with non-coincidental
drivers and think you can simply ignore it?


What?

No, I don't. I use both amps flat, no loudness. I adjust both volumes
independantly as well. I just got it set up.

So what would you do about it?


This may(!) work out well at /one/ point in
/one/ room (-yours) - but elsewhere?

So I'll clap my hands twice:

1. Nice woodwork!
2. Great courage!;-)

Don't be an ass.

James. )

[Rudi Fischer]

"James Lehman" wrote:

- There's an _acoustic_ HP in you're *fullrange*-unit.
It's possible to (nearly) compensate (especially in
such an array, Mr. Linkwitz comes to mind...), but
you stated you didn't use _any_ equalization.
- You _know_ you're dealing with non-coincidental
drivers and think you can simply ignore it?
What?
No, I don't. I use both amps flat, no loudness. I adjust both volumes
independantly as well. I just got it set up.

Yes, but as you quoted me below: In _your_ room!
(It's quite possible that some room modes are
compensating for peaks and dips in this frequency-
range.)

So what would you do about it?

- Try out this (for *fullrange*):
http://www.linkwitzlab.com/filters.htm#9
(There are other filters on this page that may be of
use: Shelving, delay, notch...). A Transform-
Calculator can be found at (sorry, didn't test it):
http://www.pvconsultants.com/audio/eq/linktran.htm

- Use something like an ECM8000 mic + ARTA
http://www.fesb.hr/~mateljan/arta/index.htm
for measurements

- Use (perhaps even passive) EQ

- Try building the *fullrange*-unit as a Bessel-Array
- with less (about half?) of these drivers. For a start:
http://www.angelfire.com/sd/paulkemble/soundf.html

(Asterixes above because - from my experience - I'm
not ready to believe this array is near flat fullrange
without heavy EQ.)

This may(!) work out well at /one/ point in
/one/ room (-yours) - but elsewhere?
So I'll clap my hands twice:
1. Nice woodwork!
2. Great courage!;-)
Don't be an ass.

Well, honestly, I guess I am;-) but you got that remark
wrong (my fault!):

_I_ definitely wouldn't dare to exhibit a project at (sorry!)
this early stage - because - if you're planning to use
this system for (post-)production (music etc) or to
sell'em, I'm pretty sure you've got SOME work (at
least add correct EQ) to do. Seriously!

But though this may sound arrogant (but isn't anywhere
near) I'm really NOT trying to discourage you!

Rudi Fischer
--
....and may good music always be with you

[James Lehman]

"Rudi Fischer" wrote in message
...

"James Lehman" wrote:

- There's an _acoustic_ HP in you're *fullrange*-unit.
It's possible to (nearly) compensate (especially in
such an array, Mr. Linkwitz comes to mind...), but
you stated you didn't use _any_ equalization.
- You _know_ you're dealing with non-coincidental
drivers and think you can simply ignore it?
What?
No, I don't. I use both amps flat, no loudness. I adjust both volumes
independantly as well. I just got it set up.

Yes, but as you quoted me below: In _your_ room!
(It's quite possible that some room modes are
compensating for peaks and dips in this frequency-
range.)

So what would you do about it?

- Try out this (for *fullrange*):
http://www.linkwitzlab.com/filters.htm#9
(There are other filters on this page that may be of
use: Shelving, delay, notch...). A Transform-
Calculator can be found at (sorry, didn't test it):
http://www.pvconsultants.com/audio/eq/linktran.htm

- Use something like an ECM8000 mic + ARTA
http://www.fesb.hr/~mateljan/arta/index.htm
for measurements





The *fullrange* driver in question is not being used down to the bottom of
its response. It does quite well down to 120Hz. So what would this do for
me? Actually, you can hear 30Hz from them, but they're just not made for
that.







- Use (perhaps even passive) EQ

- Try building the *fullrange*-unit as a Bessel-Array
- with less (about half?) of these drivers. For a start:
http://www.angelfire.com/sd/paulkemble/soundf.html





This article seems to be about using multiple drivers in a horizontal line
or 2D plan to radiate "near spherical" wave fronts. My line source array is
a vertical arrangement, designed to radiate a cylindrical wave front.

http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

I actually like the idea that these speakers create somewhat of a beam
effect. That is what makes the near field so HUGE.





(Asterixes above because - from my experience - I'm
not ready to believe this array is near flat fullrange
without heavy EQ.)

This may(!) work out well at /one/ point in
/one/ room (-yours) - but elsewhere?
So I'll clap my hands twice:
1. Nice woodwork!
2. Great courage!;-)
Don't be an ass.

Well, honestly, I guess I am;-) but you got that remark
wrong (my fault!):

_I_ definitely wouldn't dare to exhibit a project at (sorry!)
this early stage - because - if you're planning to use
this system for (post-)production (music etc) or to
sell'em, I'm pretty sure you've got SOME work (at
least add correct EQ) to do. Seriously!

But though this may sound arrogant (but isn't anywhere
near) I'm really NOT trying to discourage you!





I appriciate the links. It is all very interesting reading. And I'm sure it
all fits in there somewhere.

As far as these speakers go ~ they are what they a passive elements.
Adding some sort of active EQ to them later is another project.

I've been on crutches since April! I started on this project well over a
year ago. I was pretty excited when I got them set up enough to play sound
through them.


James. )

[Rudi Fischer]

"James Lehman" wrote
"Rudi Fischer" wrote
"James Lehman" wrote:

- There's an _acoustic_ HP in you're *fullrange*-unit.
It's possible to (nearly) compensate (especially in
such an array, Mr. Linkwitz comes to mind...), but
you stated you didn't use _any_ equalization.
- You _know_ you're dealing with non-coincidental
drivers and think you can simply ignore it?
What?
No, I don't. I use both amps flat, no loudness. I adjust both volumes
independantly as well. I just got it set up.
Yes, but as you quoted me below: In _your_ room!
(It's quite possible that some room modes are
compensating for peaks and dips in this frequency-
range.)
So what would you do about it?
- Try out this (for *fullrange*):
http://www.linkwitzlab.com/filters.htm#9
(There are other filters on this page that may be of
use: Shelving, delay, notch...). A Transform-
Calculator can be found at (sorry, didn't test it):
http://www.pvconsultants.com/audio/eq/linktran.htm
- Use something like an ECM8000 mic + ARTA
http://www.fesb.hr/~mateljan/arta/index.htm
for measurements
The *fullrange* driver in question is not being used down to the bottom of
its response.

Well, there are quite some defintions of *bottom
of it's response*:

1) fs
2) -xdB to level at 1kHz,
3) distortion xx.x% at yydB/1m
4) max excursion of voice-coil [mm]
....

It does quite well down to 120Hz.

See above.
At least 1) and 2) will not be reduced by simply
using more drivers. (OK, there's coupling...)

So what would this do for me?

Referring to the linkwitz-transform:

By *shifting* the roll-off of the *fullrange* drivers to
lower frequencies this will enable your DCX2496
24dB-LR crossover to add phase/amplitude more
properly (- nearly symmetric *slopes* in a wider
range).

Actually, you can hear 30Hz from them,

Only if your ears are max a few cm from them,
aka headphones;-)

but they're just not made for that.

ACK.

At any reasonable distance/level you'll only hear
noise (from suspension/spider/airflow) and/or distortion
if you feed that low frequencies to such small drivers.

In your setup this circuit would NOT be used to get
noticably more output at lower frequencies (the DCX's
HP will prevent that) but only to reduce the effect of a
now interfering (2.order) acoustic HP _in_crossover_
_range_ on signal/phase adddition .

The resulting higher excursion should create no
problem regarding number of drivers (IME).

It's noway near perfect (see last paragraph under
9 at link[1], you'd have to calculate/build your own
x-over with 4th order LP and 2nd order HP) but there
still should be a clearly noticable improvement.
[...]

BTW: If you were wondering why I mentioned analog
(active/passive) EQ in my previous post: If you go for
digital EQ you'll quickly discover that the DSP power of
a (single) DCX is rather limited (I did).

[1] "The above circuit can also be used to correct the
low frequency roll-off of a tweeter so that the equalized
tweeter becomes a filter section in an exact LR4 acoustic
highpass."

Rudi Fischer
--
....and may good music always be with you

[Ro_ro]

Wow. Supersize me or wha'. I hope you manage to make them sound beautiful
and not just loud! I'm sure they'll impress the birds tho', de feckin' size
of them.. Yer man wid the massive speakers. Best of luck and fair play.

"James Lehman" wrote in message
...
http://www.akrobiz.com/speakers/new/

This is one of the projects I have had in the works for quite some time
now.
I've had a hard time working on them because my ankle has been really
screwed up since I had a surgery on it in April.

They are not done yet, but they are fully functional. There are a lot of
cosmetic issues that need to be finished. These things are impossible to
move without scratching and smashing them up. So I figure I'll get them
looking as good as I can and then finish them in place.

There are three pieces on each side; (1) 36 element fullrange and (2) 4
element subwoofers. You can only see half of the 8 inch woofers. There are
just as many cones facing into the insides of the boxes, as each box
contains a dual isobaric pair.

The line array is 8 ohms. The (2) subwoofers are each 8 ohms, wired in
parallel for a system of 4 ohms. I am using the Behringer 24dB/oct. active
crossover at about 120Hz.

I used my own software and a sound card to measure all of the T/S
parameters
of the (4) woofers assembled into a single unit. I used the same software
to
tune the ports within the boxes at exactly the right frequency (22.5Hz) to
make the system respond to -3dB at 18Hz.

There are no passive crossover components in this system at all; just
speaker wire and speakers.

James. )

[James Lehman]

Thanks!

I think they sound fantastic at any volume.... and yes, they get
unbelievably loud!

James. )


"Ro_ro" wrote in message
...
Wow. Supersize me or wha'. I hope you manage to make them sound beautiful
and not just loud! I'm sure they'll impress the birds tho', de feckin'
size
of them.. Yer man wid the massive speakers. Best of luck and fair play.

"James Lehman" wrote in message
...
http://www.akrobiz.com/speakers/new/

This is one of the projects I have had in the works for quite some time
now.
I've had a hard time working on them because my ankle has been really
screwed up since I had a surgery on it in April.

They are not done yet, but they are fully functional. There are a lot of
cosmetic issues that need to be finished. These things are impossible to
move without scratching and smashing them up. So I figure I'll get them
looking as good as I can and then finish them in place.

There are three pieces on each side; (1) 36 element fullrange and (2) 4
element subwoofers. You can only see half of the 8 inch woofers. There
are
just as many cones facing into the insides of the boxes, as each box
contains a dual isobaric pair.

The line array is 8 ohms. The (2) subwoofers are each 8 ohms, wired in
parallel for a system of 4 ohms. I am using the Behringer 24dB/oct.
active
crossover at about 120Hz.

I used my own software and a sound card to measure all of the T/S
parameters
of the (4) woofers assembled into a single unit. I used the same
software
to
tune the ports within the boxes at exactly the right frequency (22.5Hz)
to
make the system respond to -3dB at 18Hz.

There are no passive crossover components in this system at all; just
speaker wire and speakers.

James. )

[Ron Capik]

James Lehman wrote:

Thanks!

I think they sound fantastic at any volume.... and yes, they get
unbelievably loud!

James. )

..snip.....

Cool. So what's their sensitivity (extrapolated to) the standard measurment
form of: x dB at 1 watt at 1 meter?


Later...

Ron Capik
--

[James Lehman]

http://www.akrobiz.com/speakers/new/

Well... I would have to only guess.
The woofers are probably about 95 to 97dB@1W@1M. There are (8) 8" cones in
motion on each side. Only four of them couple with the room. Because of
acoustic coupling, this system should be about 6dB better than just one
woofer. One of these is rated at 91dB@1W@1M by the mfg. But when I put real
measured numbers into a box program that I have, I get that if driven with
400W (which isn't unreasonable for 8 woofers) it can do 114dB@1M. But it
seems that it can only do this above 100Hz. It looks like a straight line
down from there. 95dB@40Hz, 90dB@30Hz, 85dB@20Hz. But you also have to
figure that I entered an Xmax of only 1mm into the program. One thing I
know. I only have a 100W @ 8ohm amp to drive them with. It is quite beefy
and I'm sure can handle 4 ohms no problem. But it is obvious that the
speakers can handle a lot more. As it is, the get scary loud.

As for the near fullrange line array, these things are incredibly sensitive!
A 40W amp will blow you out of the room. With an active xover at 120Hz, they
can handle WAY more than you can. I have a 150W amp on them (it sucks at 4
ohms). They are 8 ohms.

James. )







"Ron Capik" wrote in message
...
James Lehman wrote:

Thanks!

I think they sound fantastic at any volume.... and yes, they get
unbelievably loud!

James. )

..snip.....

Cool. So what's their sensitivity (extrapolated to) the standard
measurment
form of: x dB at 1 watt at 1 meter?


Later...

Ron Capik
--