In my 14 ft x 19 room I have a cloned pair of Gary Dahl’s two-way mains: Aurzahorns/Radian 745 Neo/Be drivers atop sealed GPA Altec 416-8B midwoofers. http://i190.photobucket.com/albums/z179/paukenspieler/IMG_3087_zpse3b0ffd5.jpg
The Altecs go down to 70Hz, below which my pair of Rythmik 12" sealed servo subs take over. Rythmik Audio servo subwoofer 12" F12 However, studies done by Todd Welti show conclusively that using 3 to 4 subs even in small rooms will better quell room modes and thereby yield much smoother bass response throughout much of the listening area. See Figs 47 thru 53 bare out the results, and especially Figs. 40 and 41. https://www.harman.com/sites/default/files/white-paper/12/11/2015%20-%2006%3A12/files/multsubs.pdf
There’s also a large thread on the subject where Earl Geddes discusses his slightly different approach to multi-sub solutions for achieving similar goals. Multiple Subwoofer Placement
Based on Welti’s conclusions to reduce room modes, I was then going to order the second pair of Rythmik 12" sealed subs for above system. Both pairs of subs can be daisy chained as all subs would have the Rythmik A370-XLR2 plate amp. http://www.rythmikaudio.com/download/XLR2_sealed_quickguide.pdf
However, I also want to install another system in the same room placed along the short wall opposite my other system. The mains for that system would be a pair of ESLs, probably Quad 57s. http://dave-mills.yolasite.com/resources/a_a_esl57_mod_3_komprimiert.jpg However, even raising the Quads 15 to 20” (on Arcaci stands) and placed six feet from the rear wall, the Quads will only do down to 45Hz, ergo subs for that at last lower octave. But as ESLs, like open baffle speakers, are dipoles, I presume that a pair of dipole rather than sealed subs would sound best for the Quads. And I found a thread about Danny Richie’s dual 12” woofers in OB cabinets servo controlled by Brian Ding’s Rythmik plate amps fitted with a shelving filter. Rythmik Audio 12" Servo subwoofer " GR 12" Custom Installation subwoofer Rythmik Audio • GR servo driver
These dipole servo subs appear to be in use by one Quad 57 owner. Which amp to use with SW-8-16FR OB driver? & 200 Hz?
Questions:
1.) Even if with two pairs of subs, would my two way hybrid horn/sealed Altec midwoofer (monopole) speakers prefer all Rythmik 12" servo sealed box subs? Or would they sound equally fine if one pair were dual 12” Rythmik servo dipole subs?
And would the pair of dipole subs and pair of sealed box subs still reduce room modes as effectively as would two pairs of sealed box subs?
2.) Even if with two pairs of subs, would the Quad ESL (dipole) speakers prefer all dual 12” Rythmik servo dipole subs? Or would they sound equally fine if one pair were Rythmik 12" servo sealed box subs?
And would the sealed pair and the dipole pair of subs still reduce room modes as effectively as would two pairs of dipole subs?
3.) Assuming the answer to all the above is yes, there’s the matter of setting the crossover frequency for both pairs of subs, when using either pair of mains.
My Altec midwoofers play down to 70Hz. And the Quads, if placed 6 ft or so from the rear wall-and if raised 14 to 20” on (Arcaci) stands-should do down to between 45 and 40Hz.
Accordingly, I would initially set the sealed subs and the dipole subs plate amps to cross and be in phase with the Altec midwoofers and Quad ESLs, respectively, and confirm that each pair of subs works nicely with alone with its own mains. I would need to note these settings for each subwoofer pair to supply bass to its own mains, as the Rythmik plate amps have no memory for storing multiple groups of subwoofer settings.
Next, when using the pair of monopole mains I would then have to readjust the dipole subs to properly cross with and be in phase with mains.
Alternately, when using the pair of dipole mains I would then have to readjust the monopole subs to properly cross with and be in phase with those mains.
Now the question is, whether I use the pair of monopole or pair of dipole mains, regardless of well would you expect these two pair of daisy-chained dipole and monopole servo subs to sound together when both pairs (properly crossed and phase adjusted) are supplying bass for either pair mains?
And at the same time, regardless of which mains I’m playing, will a pair of dual 12” Rythmik servo controlled dipole subs work well with my pair of Rythmik 12" servo sealed subs to minimize room modes?
Last but not least, while deciding which part of which forum to place my post I found some unexpected controversy on the very notion of open baffle subs. A “stupid idea”? http://www.diyaudio.com/forums/subwoofers/295060-open-baffle-subwoofer-design-4.html I’m probably not expert enough to even enter into a debate on this. However, in order to avoid making a bad investment and/or overcomplicating my subwoofer scheme, I am reaching out for experienced and impartial feedback on dipole subs, dual 12" Rythmik servo dipole subs in particular and using them simultaneously with Rythmik 12" sealed servo subs. Thank you.
The Altecs go down to 70Hz, below which my pair of Rythmik 12" sealed servo subs take over. Rythmik Audio servo subwoofer 12" F12 However, studies done by Todd Welti show conclusively that using 3 to 4 subs even in small rooms will better quell room modes and thereby yield much smoother bass response throughout much of the listening area. See Figs 47 thru 53 bare out the results, and especially Figs. 40 and 41. https://www.harman.com/sites/default/files/white-paper/12/11/2015%20-%2006%3A12/files/multsubs.pdf
There’s also a large thread on the subject where Earl Geddes discusses his slightly different approach to multi-sub solutions for achieving similar goals. Multiple Subwoofer Placement
Based on Welti’s conclusions to reduce room modes, I was then going to order the second pair of Rythmik 12" sealed subs for above system. Both pairs of subs can be daisy chained as all subs would have the Rythmik A370-XLR2 plate amp. http://www.rythmikaudio.com/download/XLR2_sealed_quickguide.pdf
However, I also want to install another system in the same room placed along the short wall opposite my other system. The mains for that system would be a pair of ESLs, probably Quad 57s. http://dave-mills.yolasite.com/resources/a_a_esl57_mod_3_komprimiert.jpg However, even raising the Quads 15 to 20” (on Arcaci stands) and placed six feet from the rear wall, the Quads will only do down to 45Hz, ergo subs for that at last lower octave. But as ESLs, like open baffle speakers, are dipoles, I presume that a pair of dipole rather than sealed subs would sound best for the Quads. And I found a thread about Danny Richie’s dual 12” woofers in OB cabinets servo controlled by Brian Ding’s Rythmik plate amps fitted with a shelving filter. Rythmik Audio 12" Servo subwoofer " GR 12" Custom Installation subwoofer Rythmik Audio • GR servo driver
These dipole servo subs appear to be in use by one Quad 57 owner. Which amp to use with SW-8-16FR OB driver? & 200 Hz?
Questions:
1.) Even if with two pairs of subs, would my two way hybrid horn/sealed Altec midwoofer (monopole) speakers prefer all Rythmik 12" servo sealed box subs? Or would they sound equally fine if one pair were dual 12” Rythmik servo dipole subs?
And would the pair of dipole subs and pair of sealed box subs still reduce room modes as effectively as would two pairs of sealed box subs?
2.) Even if with two pairs of subs, would the Quad ESL (dipole) speakers prefer all dual 12” Rythmik servo dipole subs? Or would they sound equally fine if one pair were Rythmik 12" servo sealed box subs?
And would the sealed pair and the dipole pair of subs still reduce room modes as effectively as would two pairs of dipole subs?
3.) Assuming the answer to all the above is yes, there’s the matter of setting the crossover frequency for both pairs of subs, when using either pair of mains.
My Altec midwoofers play down to 70Hz. And the Quads, if placed 6 ft or so from the rear wall-and if raised 14 to 20” on (Arcaci) stands-should do down to between 45 and 40Hz.
Accordingly, I would initially set the sealed subs and the dipole subs plate amps to cross and be in phase with the Altec midwoofers and Quad ESLs, respectively, and confirm that each pair of subs works nicely with alone with its own mains. I would need to note these settings for each subwoofer pair to supply bass to its own mains, as the Rythmik plate amps have no memory for storing multiple groups of subwoofer settings.
Next, when using the pair of monopole mains I would then have to readjust the dipole subs to properly cross with and be in phase with mains.
Alternately, when using the pair of dipole mains I would then have to readjust the monopole subs to properly cross with and be in phase with those mains.
Now the question is, whether I use the pair of monopole or pair of dipole mains, regardless of well would you expect these two pair of daisy-chained dipole and monopole servo subs to sound together when both pairs (properly crossed and phase adjusted) are supplying bass for either pair mains?
And at the same time, regardless of which mains I’m playing, will a pair of dual 12” Rythmik servo controlled dipole subs work well with my pair of Rythmik 12" servo sealed subs to minimize room modes?
Last but not least, while deciding which part of which forum to place my post I found some unexpected controversy on the very notion of open baffle subs. A “stupid idea”? http://www.diyaudio.com/forums/subwoofers/295060-open-baffle-subwoofer-design-4.html I’m probably not expert enough to even enter into a debate on this. However, in order to avoid making a bad investment and/or overcomplicating my subwoofer scheme, I am reaching out for experienced and impartial feedback on dipole subs, dual 12" Rythmik servo dipole subs in particular and using them simultaneously with Rythmik 12" sealed servo subs. Thank you.
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I agree with Scott. Tho there is a bit more than that. When combining both in a specific layout eg monopole behind the dipole will create a cardioid response. There is considerable power wasted due to the cancellation all dipoles exhibit. In use would also require DSP processing to integrate properly. This also creates an additional headache that cannot be ignored. By doing such in a small room is not going to happen. The room dimensions are simply too small to pull off cardioid response at sub frequencies due to their wavelength. Only Outdoors and or in a VERY large open room can this be achieved.
Seeing that what you are trying to achieve is virtually identical to Gary Dahl's (your cloned system) and as described by Lynn Olson in his "Beyond the Ariel" thread. Lynn walked away from Dipole sub bass a few years back. I cannot say as to what he has concluded on that subject lately, but my recollection of the subject was to use a large high power sealed sub and a plate amp. Please forgive me Lynn if I got this wrong.
Myself personally would use a TL sub for such a task. My choice has to due with a low min. group delay that is just a tad higher than a sealed, but with all the advantages of a Bass Reflex's extension. My current TL has a min group delay of ~7.5ms and an extension down to 26Hz without equalization. After analyzing my music library of roughly 15k find very few that can even hit an A note, eg 26.5Hz.
Seeing that what you are trying to achieve is virtually identical to Gary Dahl's (your cloned system) and as described by Lynn Olson in his "Beyond the Ariel" thread. Lynn walked away from Dipole sub bass a few years back. I cannot say as to what he has concluded on that subject lately, but my recollection of the subject was to use a large high power sealed sub and a plate amp. Please forgive me Lynn if I got this wrong.
Myself personally would use a TL sub for such a task. My choice has to due with a low min. group delay that is just a tad higher than a sealed, but with all the advantages of a Bass Reflex's extension. My current TL has a min group delay of ~7.5ms and an extension down to 26Hz without equalization. After analyzing my music library of roughly 15k find very few that can even hit an A note, eg 26.5Hz.
Most distressing. For one thing I do not at all like the thought of using DSP. I only use digital sources and one D/A conversion (albeit from a high quality DAC) is all I want to do.
But will sealed Rythmik servo monopole subs blend well with ESLs like the Quad 57s or 63s, or other dipoles like open baffles? Or are you suggesting that I build TL subs to work with those kinds of speakers? If so, will they be compatible with my sealed monopole subs to work with them simultaneously to reduce room modes?
As for actual bass extension, I doubt that there's much in my collection either that gets to 25Hz, so 35Hz to 30Hz should be fine. But please advise further on this multi-sub dilemma.
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I use the 12" genesis sealed servo subs with my Quad's and found the combination perfectly pleasing. However I suspect the Rythmik's are even better. All this might be rather room dependent and Dipole do not excite room modes in the wall sealed sub's do. I suspect H frame open baffle sub's would complement your Quads the best. Have you talked to Brian at Rythmik? I would trust his advice.
Olos depending how adventurous you are (and maybe how deep your wallet is too) you might be the only one around to explore the combination of a multis set up with pairs of both sealed and open baffle subwoofers. It probably would take some care in dialing in everything but I imagine you might just end up with the best of all possibilities, and even if not THE BEST, I'm sure it would be in the upper end of what's possible.
Step One always the same: buy a mic and install REW. Big surprise, you can just use your laptop mic and REW (and not even donate to REW) and get pretty good testing, no kidding.
http://www.diyaudio.com/forums/subw...-mic-too-bad-casual-builders.html#post4942067
Best method is to make a jig to repeatedly locate your mic in the same place where your head normally is.
Big differences as you move speakers around your room, even inch by inch in the case of upper range.
Below 130 Hz with sharp slope and clean speakers, no localization in a home music room on music.
Ben
http://www.diyaudio.com/forums/subw...-mic-too-bad-casual-builders.html#post4942067
Best method is to make a jig to repeatedly locate your mic in the same place where your head normally is.
Big differences as you move speakers around your room, even inch by inch in the case of upper range.
Below 130 Hz with sharp slope and clean speakers, no localization in a home music room on music.
Ben
So to paraphrase Tubamark’s at post #1375 here http://www.diyaudio.com/forums/subw...ultisub-setup-temporary-rental-apartment.html , even in an apartment (like my tiny 14 ft x19 living room) a sub’s XO, phase and level controls alone will almost always give excellent results and in almost every room. However, without DSP it’s a long and tedious process? Presumably, a two person effort would at least expedite things; one listens in a chair and the other tweaks each sub’s plate amp.
But though I prefer not making any kind of DSP hardware a permanent install, as my music source is a laptop, is there Windows based software that can help better fine tune and fast track the process?
I am hardly expert on room acoustics and not familiar with REW software. Nice to know that a cheap laptop mic works fine with it; thanks Ben. But other than delivering the slam that OB subs apparently can’t deliver (hardly a big necessity I suppose if I’m using 4 subs in a small room), why did nickd say here that Danny Richie ran the sealed Rythmik sealed subs 180 degrees out of phase with the OB subs? GR Research and Rythmik co-developed OB subwoofer
Does doing so allow both these different kinds of subs to be used together, as well as to aide each other in cancelling room modes?
I would like to use two pairs of subs simultaneously if both pairs blend well with Quads and my two way hybrid horn speakers. And if both pairs of subs would greatly improve the response beyond basic acoustical room treatment-along with minimizing IM distortion, as each sub could play less loudly (not that condo living nor my ears allow for much in the way of high SPLs).
However, if Greebster knows the science proving that the Danny Ritchie/Brian Ding OB servo subs and Ding sealed subs would still be at odds with each other-particularly in my 14 ft x 19 room size-then is there any reason why TL subs would work better with the Quad 57s than would a second pair of my 12" sealed servo subs?
If so, then what about these pre-built well reviewed TL subs? TBI Audio Systems - Products
Tesla13bmw uses them, though two pairs of Quads are beyond my budget. Dipole subwoofer for ESL57 - Page 4 - DIY Audio Projects - StereoNET
These are yours? Genesis Advanced Technologies G-928 Servo-Subwoofer Review - Dagogo | A Unique Audiophile Experience The most I could afford is to have Jim Salk build me a second pair of subs-either another pair of Brian Ding’s Rythmik 12" sealed servo subs or the Danny Richie/Brian Ding OB servo subs. But as Greebster explained, OB subs and sealed subs are not really compatible, I’d consider those Magellan TL subs for the Quads but only if they were fully compatible with my Rythmik 12" sealed servo subs and that DSP was not required.
Brian Ding and Enrico Castagnetti have always replied to my emails, and Briansupplies servo plate amps for Danny Ritchie’s OB subs. I asked them if these OB subs and Brian’s 12" sealed servo subs have compatible projection patterns, and about be able to use them simultaneously either the Quads or with my horn speakers. But this time they never replied.
Actually what I have is the Genesis Servo 12 first generation which uses a kevlar cone driver. But I also have some other subwoofers to enjoy include a pair of the long gone Nelson Reed 1201's, a home made 12 ft long version of the Bose Cannon with a DynAudio driver, and lastly two pair of 18" Goldwoods that MJK uses in his H Frames but in my case I currently have them into a diy version of the old Celestion 600's if anyone can remember those, but with an odd twist to take advantage of Nelson Pass's slot loading idea. Now that might make it seem that I am a bass head but really I am not. I like to dial down the subs where they simply make a seamless blend with the main drivers into the lower octaves. While mine are all more of less in the "affordable" category, I have heard better subwoofers than any I own (the Krell Master Reference sub comes to mind). In fact I suspect your Rythmik subs are probably superior too, and that would go for both the sealed and open baffle. One thing I consider essential in getting a sub dialed in is a full phase control. A simple 0 / 180 switch doesn't give you as much fine control. This is especially so in matching the "attack" of the notes leading edge, with the "body" of the instrument. Solo piano helps with this, along with solo upright bass. When you get it right you'll know. Maybe others know alot more than I do about this but I fully suspect that combining the multi sub approach of all Rythmik servo drivers and amps with a pair sealed and a pair in H frames just might give you one of the best set ups ever. You will probably have to do the work as far as room placements go but hey you're going to have an awful lot of fun along the way!
Because as soon as you have much separation between speakers around a room, phase and even polarity are strictly a matter of chance. Run the speakers with polarity the same and you get one curve. Reverse the polarity of one speaker and you get another curve. You'd be surprised how hard it is to choose which curve looks like it will sound better.
For a few years, I ran a giant OB with the half-way-around distance a couple of feet*. Let's say you have a fine sub with a proper resonance, say 20 Hz. In an OB, that resonance will be 20 Hz. Not a bad place to have a bump (esp since you'd EQ to get that kind of bass boost so the speaker sounds flat to your ears).
Again, you want heterogeneity. Anybody who has spent time with REW in a house knows the way to good bass is through statistics. The room characteristic will dominate the response of even the best single sub. So two subs is a vast improvement and so on but with diminishing increments.
Ben
*part of the art of making proper OB speakers is to have varying dimensions. Duh.
Thanks Octavia for that very interesting tour through your subwoofer experiences. A Krell sub? Indeed, MJK’s passive OBs were the very first OBs that I ever thought of cloning.Jordan JX92S OB with a Goldwood GW-1858 Woofer in an H Frame Project But I’ve vowed to never again clone jor buy anyone’s speakers that I couldn’t audition first. Sadly, Long Island truly is an audio enthusiast’s no-man’s land. I can just about count on one hand those who I’ve personally found here who are into it. Pardon the rant, but it’s too true.
I suppose those 18” Goldwoods would be too slow for the Quads, if you went ahead and built the H-frames. While considering the dual 12” Danny Richie /Brian Ding OB servo sub, I also looked at John Reekie’s review of dipole subs, which also included Nelson Pass’s design. http://www.hifizine.com/2012/12/subwoofer-origami/ I don’t quite understand all the physics involved and I get no replies.
Here’s the plate amp on the pair of sealed subs Jim Salk built for me. http://www.rythmikaudio.com/images/XLR2.jpg and http://www.rythmikaudio.com/download/XLR2_sealed_quickguide.pdfIt does have a variable phase control, not a switch. Presumably, more costly subs allow remote control of those adjustments and for memorizing multiple settings.
A pair of the Ritchie/Ding OB subs wouldn’t set me back too much. However, Greebster’s claims that DSP would be necessary to get them and my sealed Rythmik subs to interface correctly, in my small room.
Despite its virtues, DSP would negatively complicate things with the system I’m trying to build. As I don’t play vinyl, I plan to go for a fairly high end DAC -and I would need two of them to do DSP between the mains and the subs via USB ports from my laptop. And without assurances from Danny Ritchie and Brian Ding that DSP was not necessary to successfully use OB and sealed subs simultaneously, then a pair of OB servo subs would make no sense (to augment the Quad ESL 57’s low end), if OB subs cannot interface with my pair of Rythmik 12" sealed servo subs to reduce room modes, without resorting to DSP in my 14 ft x 19 room.
In which case, TL subs or second pair of sealed Rythmik subs? And you did say that you’re happy with how your Genesis sealed subs work with the Quads.
I don’t get it. By heterogeneity, do you mean that it’s best to use my pair of Rythmik 12" sealed servo subs with another pair of either 10” or 15” sealed subs (like I think Earl Geddes recommends, though I didn’t understand why)? Or do you mean it’s best to use my sealed subs with a pair of OB subs? If yes, I don’t get why so either. So what kind of subs should I get for the second pair, regardless of my mains (e.g. two-way horns/sealed midwoofers, Quad ESLs, OBs)?
In any case, while I wouldn’t mind learning how to use REW if I can do using only my system DAC to set up the subs (e.g. not simultaneously playing my mains which are fed from the amp fed from the DAC fed from my laptop). Just as long I don’t have to leave DSP in the system afterwards, which would require a second (lesser sounding) DAC. Pardon my bias but I tried to justify it earlier.
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