The Ultimate Subwoofer

what does high SPL generated in a small room from all of those woofers do to another speaker cabinet?
Am I right in thinking it will "pump" the Swing and force the driver to move from the air pressure and cause distortion? It would be interesting to put an oscilloscope on your main speakers in the room and see what microphone effects can be measured.

Using two of these in a room you could make some spooky party tricks with a balloon sitting on the floor. Expand balloon, contract balloon, move a little bit to the left, expand, contract, move a little to the left.

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what does high SPL generated in a small room from all of those woofers do
to another speaker cabinet?

I have no idea and this is not the idea behind the subwoofer - just generating high SPL's...

The idea is to genreate the needed SPL asked with normal playback levels but then without any distortion (no moving diaphragms as a result when using many drivers giving a huge total diaphragm surface - Sd will be 1,728m^2!!)

Am I right in thinking it will "pump" the Swing and force the driver to
move from the air pressure and cause distortion? It would be interesting
to put an oscilloscope on your main speakers in the room and see what
microphone effects can be measured.

It will not affect the Swings performance when the sub is integrated and EQ-ed properly (phase, time and SPL). The sub will do what the Swings don't do... and work together in their overlapping frequency range.

Using two of these in a room you could make some spooky party tricks with
a balloon sitting on the floor. Expand balloon, contract balloon, move a
little bit to the left, expand, contract, move a little to the left.

That balloon will surely be presurised and moved around in the room (you won't need a balloon to visualize things, you will sense this with your body).

Bert

--
BD-Design - Only the Best!

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It will not affect the Swings performance when the sub is integrated and
EQ-ed properly (phase, time and SPL). The sub will do what the Swings
don't do... and work together in their overlapping frequency range.

Hi Bert,

Although the above would be true by itself, it is kind of unrelated;
The low frequency waves just *will* move the diaphragm (Swings' woofers), even into areas they shouldn't. If that wouldn't give distortion by itself, it will give electrical feedback.

Probably no big deal, but something to think about anyway. And just interesting ...

Peter

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Hi Peter,

Although the above would be true by itself, it is kind of unrelated;
The low frequency waves just *will* move the diaphragm (Swings' woofers),
even into areas they shouldn't. If that wouldn't give distortion by
itself, it will give electrical feedback.

At second thoughts it became clear to me that this is what Mike was talking about...

Probably no big deal, but something to think about anyway. And just
interesting ...

I can be a big deal if the amplifiers are not able to control this "feedback" enough (EMK is this called if I remember correctly) which then will disturb the accuracy. No worries with the CrazyA's or the Ultimate Subwoofer though but the bigger the receiving diaphragm and the lower the damping of the speaker system (high Q) the stronger the effect....

Bert

--
BD-Design - Only the Best!

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what does high SPL generated in a small room from all of those woofers do
to another speaker cabinet?

This is a very good remark (just because I thought about that too, hehe :swoon.

You could already scope measure it electrically, because each driver acts as a microphone just the same.

Note : I thought about this myself, because Bert has the sub opposite to the Swings, so the sub would blast (the most) direct(ly) onto the Swings' woofers. Btw, it is a very normal procedure to have the sub at the other end of the room, although I would not do that.

In the end it must be important somewhere, were it only because of the papers by mr. Duelund GC referred to (in the other thread). On that matter, what he found, I found too and separately from him; Whatever it exactly is that is behind this thinking (from both him and me), you could say that it is exactly that what makes it legit to have subwoofers around in the first place. It is about the reflecting waves in the room interacting with the speakers. Or better : the speakers interacting with them. It can be wrong and it can be right.

Btw, I did not notice explicit anomalies at Bert's place with his current sub, so all is just theories. On another note, it is XXHighEnd which makes those things (much) more right in the first place.
Complicated stuff ... :yes:

Peter

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Peter,

Note : I thought about this myself, because Bert has the sub opposite to
the Swings, so the sub would blast (the most) direct(ly) onto the Swings'
woofers. Btw, it is a very normal procedure to have the sub at the other
end of the room, although I would not do that.

Only with impulses the sound will "blast" directly to the Swings or suck out the energy if it is a negative pulse, with a continious signal (organ, contrabass, sythesizer, etc.) then the air in the whole room will be compressed and decompressed with the woofers as center point...no real direction with those extreme low frequencies.

The same situation but then outside (free air) acts rather differently.

In my situation the sub waves produced by the Swings and the Subwoofer will meet eachother at my listening position.... that is why timing is sooo important, even with sub frequencies if provided by both systems!!

Bert

--
BD-Design - Only the Best!

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Yep Bert & Peter

However "blasts" or "sucks" will likely not reach the mbar range but still keep it self to low pressure db's. And I don't think anybodys listening room is that airtight that such attempts to alternate from over pressure to vacuum would be a real problem here.

The SWING is "protected" by partly the connected amp and partly by it's enclosure.
If I disconnect the BD30's from the BD15's I can move the diaphragmes somehow easily, but with the amp connected, they become extremely stiff. So the control is still in the hands of the amp rather than a woofer wall alternating deep low.

The wall will neither act like a Mike Tyson fist but simply just move air in the low subs when called for.
If the SWING and the wall works like a parallel piston (in phase at any frequency) the room will have to deal with the pressure alone. And that's another case.

But let's see what the rumble project at Brinkersweeg can show us. :wacko:

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I agree with GC. When you think about pressure differences due to soundwaves, don't think about those films you saw about the pressure wave after a nuclear explosion... :wink:

When I was a kid, a friend would put a candle in front of the reflex port of his speaker (of a plastic all-in-one set) and the flame would dance a little back and forth. Then he would switch on loudness, hilarious for teenagers, of course. Anyway, the approximate amount of air movement we could see in that flame, will now be distributed across Bert's entire wall-o-sub. I think his Swing's will be alright.

Ivo

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I agree with everybody ... :yes:

But I want to emphasize that the candle story may be related too much to the plastic stuff ...
I can show you the (not leight) curtains go 50cm sideways for 20 seconds because of the port of my sub, and you don't even hear anything (this would be below 18 Hz or so). This is just Zappa and The Yellow Shark, fourth track.

This is with normal 1:1 calibrated subs (I mean, no extra gain). I play somewhat louder than average though ...
:biglol:

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I agree with everybody ...

But I want to emphasize that the candle story may be related too much to
the plastic stuff ...
I can show you the (not leight) curtains go 50cm sideways for 20 seconds
because of the port of my sub, and you don't even hear anything (this
would be below 18 Hz or so). This is just Zappa and The Yellow Shark,
fourth track.

This is with normal 1:1 calibrated subs (I mean, no extra gain). I play
somewhat louder than average though ...
:biglol:

Ha ha ha Peter...

You mean your curtains moves +- 25 cm's?? :scared: 18 times per second?

Or are they exposed to air pistol DC? Then be careful with the absolute phase or the curtains end up in your ports and cabs..he he :cool:

What a blowjob :heat:

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these monsters will be so big that dB/w/10m is more appropriate.
But let's consider 112dB/W/m with a 30W amplifier, that's 14.5dB of gain above one watt isn't it?

126.5dB of clean power is nothing to be sneezed at, However: it will clear your sinuses out. :grin:
Accidentally dropping a stylus will cause injury.

The effect I was considering may be very small, but at the quality Bert is aiming for it may be significant at higher volumes. It might alter your crossover choices or speaker placement.

I take my hat off to you Bert, (before your sound system blows it off my head).
It will be very interesting to see the progress.

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Hi Mike..... talking about tsunamis of sound....

Once back in my younger days I had the pleassure to be a drummer for 15 years. That's not my story, but parallel to that I had the unpleassure to be the so called "mixer-man" at 100's of rock concerts. Even for rather big names. :blush:

Common for most bands are that they want to go loud. Real loud. OK that should maybe not be a problem, but very often it were. The PA speakers and the wattage juice available were often resulting in cracked and clipped sound. Huh... idiotic, but they insisted.

But at least I remember one occation or two where that was not the case:

1) Out door scene
2) 36 18" W-sub-basshorns equalized flat to 15 Hz
3) 36 18" basshorns 60-125 Hz
4) 48 2 x 12" horns 125- 1500 Hz
5) 24 4" hornloaded compression drivers 1200 - 5000 Hz
6) 96 treble horn drivers 5000 - and up Hz
7) 50.000 watts total amp juice 8 Ohm.
8) All gear branded Cerwin Vega

Now, it was a pleassure to crank up the master volume as it seems suddently that the headroom limits were unlimited. It was really clean and it could go really loud.

I were sitting approx 100 m from the scene and my sound pressure meter weighted showed 120 db peak when it were loudest.

Ha ha... How in the Christ name were it possible for the audience to stand just next to the PA colloms adoring the bands noise? One poor drunk guy even fell asleep with his head into one of the sub-bass horns!!! He were taken away and carried to the hospital with internal injuries. I'm not kidding.

I would not say I can generate the same situation in my listening room, but when I let all juice go into the SWINGs with a 400 W old vintage SS amp I have, my body simply protest. The bass kick is violence :cool:

Shall we say I hit a 125 - 130 db in my listening position? Now add a sub-sub that can follow...and the hospital is unavoidable.

GGeerrnneerr drrrrrrrrr :grin:

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I would not say I can generate the same situation in my listening room,
but when I let all juice go into the SWINGs with a 400 W old vintage SS
amp I have, my body simply protest. The bass kick is violence

Shall we say I hit a 125 - 130 db in my listening position? Now add a
sub-sub that can follow...and the hospital is unavoidable.

GGeerrnneerr drrrrrrrrr

There goes the warranty! :read:
That SS amp is a good thing to have when the noise floor is raised by the teenagers next door with their doof doof and their brick music. (Brick = manufactured rock)
You can upset them with bagpipes and accordions. OTOH Bert will be able to open his windows and simulate the police helicopter.

There are too many people making music who want quantity over quality. Sadly it appears to be getting worse. In the future the Ipod generation will be looked back on as a strange step backwards in music. They are printing wallpaper instead of painting stories and landscapes. :cry::

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Hi Mike,

There goes the warranty!

The Swing will not break down that easy... :cool:

You can upset them with bagpipes and accordions. OTOH Bert will be able to
open his windows and simulate the police helicopter.

I can already do that with my present horn subs.... :wink:

There are too many people making music who want quantity over quality.
Sadly it appears to be getting worse. In the future the Ipod generation
will be looked back on as a strange step backwards in music. They are
printing wallpaper instead of painting stories and landscapes.

Think positive, with the Internet people learn....and when their youth is gone then they will get wise (as long as they didn't destroy their hearing...)

Bert

--
BD-Design - Only the Best!

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Mike,

Accidentally dropping a stylus will cause injury.

It will, but the biggest danger will be rumble and feedback.... if the system plays frequencies at the same resonance frequency of the turntable...

I take my hat off to you Bert, (before your sound system blows it off my
head). It will be very interesting to see the progress.

Thanks... you will find out more soon enough! :heat:

Bert

--
BD-Design - Only the Best!

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