Doug,
I don’t know specifically what you are not buying, but I’m not selling anything in post #17, where I point out the problems of trying to guess what frequency of a fixed 24 dB per octave Linkwitz-Riley crossover may or may not not integrate well with existing subwoofers (and 8” woofers) using a passive crossover built in to a speaker, without testing the speakers to see what is appropriate.
In other words:
He can definitely run the Vandersteens their full bandwidth and add multiple subs to increase the in room low frequency level, but proper bass management options (which would include delay, parametric EQ and variable upper and lower crossover frequencies) used with some test gear would give better results than a guess as to what fixed frequency will “work”.
The OP presumably has put a lot of money and thought into the purchase of his main speakers, I just pointed out that proper integration of additional subs takes more than adding them in at an arbitrarily arrived at fixed frequency.
Art Welter
All the confusion!
I didn't expect nearly as many or as complicated replies as I got. I thought a few people might just send me some numbers. I've replied to some of the responses.
Overpowering the Vandersteens shouldn't be a problem as both high and low output have adjustable gain. I will have to open the case to reach the on-board pots.
A couple more notes:
Thank You everyone for your input.
-Byron
I didn't expect nearly as many or as complicated replies as I got. I thought a few people might just send me some numbers. I've replied to some of the responses.
I'm considering that. I'm looking at the Elliott Sound Products Linkwitz transform circuit, but that can wait until later.
Actually, it's not bad at all. But it could be better
But I already bought the boards. I figure I only have to get it right once. It is a proper 2-way X-over with adjustable gain for high-pass and low-pass output. Adjusting the frequency of the filters is possible, but a hassle.if your crossover can send the signal to the speakers and the subs, and have a variable slope and x over point/s . . .
if your eq cant do that.
build one that can
Due to the variety and complexity of responses, and the general lack of consensus, I'm considering doing that.
Yes, that's the plan. It's a 2-way active X-over with 12dB or 24dB/octave slopes for high and low pass.
Overpowering the Vandersteens shouldn't be a problem as both high and low output have adjustable gain. I will have to open the case to reach the on-board pots.
I'm sure that more is better, but two subs are enough for me. These things are BIG.
A couple more notes:
- It seems some readers didn't realize the ESP active X-over is 2-way, so the Vandersteen's passive X-over frequencies and slopes should be irrelevant. Please correct me if I'm wrong.
- The active X-over's outputs are in phase, and a 40Hz sound wave is 28' long, so I figure that as long as the subs are within, say, 7' of the main speakers, lobbing within the very narrow X-over region should not be an issue. Unless the Vandersteen's 7" woofer is phase-shifted because of the passive X-over or box alignment. Then I may have a problem.
- I think the "active acoustic coupler" is not a just sealed woofer, but a power-assisted passive radiator. That is - both a driver and a PR for the 7" woofer. It is certainly weighted like a PR. But I could be mistaken.
Thank You everyone for your input.
-Byron
Sorry Im confused with this
If he is XOing at 80Hz then he is completely removing the Vandersteen's 10" frequency range so it will not even move any more, correct? How does that impact the 8" driver performance above 80Hz with the introduce phase shift. Are you saying it effects the XO between the 8" and the mid range?
I definitely agree on adding more subs to the room and leave the Vendersteens as they are.
Hi again,
Sorry, I was not trying to link to page #138, but to page #1 of the Geddes approach thread:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html, and
particularly to Post #5 by markus76, and his multisub setup reference:
mehlau.net > audio > multisub
The Geddes approach uses the main speakers as full-range speakers without low cut, so the Vandersteen 3As should work just fine in this type of scheme. Adding additional subwoofers with individual level, and phase adjustments could result in an improved overall sound field provided some procedure like the multisub setup above is followed.
Regards,
(Y'all are too quick for me.)
Sorry, I was not trying to link to page #138, but to page #1 of the Geddes approach thread:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html, and
particularly to Post #5 by markus76, and his multisub setup reference:
mehlau.net > audio > multisub
The Geddes approach uses the main speakers as full-range speakers without low cut, so the Vandersteen 3As should work just fine in this type of scheme. Adding additional subwoofers with individual level, and phase adjustments could result in an improved overall sound field provided some procedure like the multisub setup above is followed.
Regards,
(Y'all are too quick for me.
)
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I misread the OP, thinking that the active crossover would be used only on the new subs, rather than also crossing over the Vandersteens.
You are correct, with the crossover used on the top cabinets he will be removing the Vandersteen's 10" frequency range, rather than using them along with the new subs, my original (incorrect) assumption.
My mistake, I just didn't wrap my head around someone throwing away the output of a driver with flat output to the mid 20 Hz range that takes up over half of a large cabinet.
Hi again,
Sorry, I was not trying to link to page #138, but to page #1 of the Geddes approach thread:
http://www.diyaudio.com/forums/subwoofers/134568-multiple-small-subs-geddes-approach.html, and
particularly to Post #5 by markus76, and his multisub setup reference:
mehlau.net > audio > multisub
The Geddes approach uses the main speakers as full-range speakers without low cut, so the Vandersteen 3As should work just fine in this type of scheme. Adding additional subwoofers with individual level, and phase adjustments could result in an improved overall sound field provided some procedure like the multisub setup above is followed.
Regards,
(Y'all are too quick for me.
To do this properly, EQing devices are needed (ie. The DCX ) also an AVR or pre/pro with proper bass management tools are required. To run mains set to LARGE and to also have content out the subwoofer change requires a subwoofer setting called LFE+Mains. This is where the bass still exists in the main channels but additionally that bass (Below a definable Frequence setting) is sent out the subwoofer channel too.
If this is purely a two channel setup and there isnt any bass management available then a DCX or MiniDSP (2x8 board) will handle the bass management for you too.
FWIW, I run my mains full range and run the LFE+Main setup.
Like you, I also run mains all the way down, with additional subs.
One problem that the OP will have with the "big dead cabinets" is the undriven 10 inch speakers will actually cause a reduction in LF at some frequency, like a bass trap. The harder the new subs are driven at that frequency, the more the "drone" will suck up that energy.
I have measured as much as a 6 dB reduction at certain frequencies with an undriven cabinet next to a driven cabinet. The resonance of the undriven cone may also cause an after ring at higher frequencies.
Disconnecting the "dead" speakers from the passive crossover, and shorting the unused speakers with a short piece of wire should pretty much eliminate those problems.
That said, the Vandersteen passive crossover may use the 10" speaker's inductance as part of the 8" crossover - removing any element in a passive crossover can have unintended consequences in frequency and phase response.
There are a lot of moving parts in the OP's "simple" question.
Art Welter
Had I not actually measured it, I would not have thought the effect of an undriven cabinet would be nearly as much as it can be.
In the outdoor test shown in the screen shot below, the green trace is a single cabinet output, using a 28 Hz BW24 HP and a 100 Hz LP, the same filters are used for all three traces with the same drive level.
The blue trace shows two of the same cabinets side by side, the second speaker shorted out (a wire between the + and - terminals), so the additional cabinet is just a "dummy", increasing frontal area.
The increased frontal area adds about 1 dB gain overall.
The lavender trace shows the addition of the second cabinet with the speaker not shorted. The addition of the second cabinet in this case increases the 40-45 Hz area, then causes a sharp dip, followed by more rising response, and another dip.
The difference a "dead" cabinet makes to the response curves of a powered cabinet can be rather interesting.
Art Welter
Attachments
Maybe I should stop trying EQing my low frequency setup until I remove the extra woofers
Thanks for posting the measured difference.
Well, you may at least want to short the unused cabinets out before going crazy with EQ
.If you have any low Fs strong magnet 10" you want to get rid of cheap, I have a big, ugly TH looking for a pair since I "oopsed" a pair of AR-2 woofers during a sine wave test.
Have HF drivers to trade...
Originally Posted by weltersys
If you have any low Fs strong magnet 10" you want to get rid of cheap, I have a big, ugly TH looking for a pair since I "oopsed" a pair of AR-2 woofers during a sine wave test.
By cheap, I meant something close to the cost of the AR-2 woofers, which I found abandoned on the side of Highway 14.
I already have three subs in my workshop, the fourth “totem pole” TH was just made for fun, though I was looking forward to using it, as it had much deeper extension than the others.
Post #11, 17, 27
http://www.diyaudio.com/forums/subwoofers/168502-ar-1-woofer-new-enclosure-2.html
Turns out the AR-2 woofers are nothing like the AR-1 woofers...
If you have any low Fs strong magnet 10" you want to get rid of cheap, I have a big, ugly TH looking for a pair since I "oopsed" a pair of AR-2 woofers during a sine wave test.
By cheap, I meant something close to the cost of the AR-2 woofers, which I found abandoned on the side of Highway 14
. I already have three subs in my workshop, the fourth “totem pole” TH was just made for fun, though I was looking forward to using it, as it had much deeper extension than the others.
Post #11, 17, 27
http://www.diyaudio.com/forums/subwoofers/168502-ar-1-woofer-new-enclosure-2.html
Turns out the AR-2 woofers are nothing like the AR-1 woofers...
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