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Post by djoel on Dec 10, 2015 10:20:00 GMT -5
Hello folks, don't know if I should have just posted this over at the Stupid Question thread, but I'll ask here and see where it gets me.
I purchased a pair of SVS of SB12-NSD sub over the Black Friday sale to put at opposite corners but it appears my Wife commandeer one of the corner for her knitting items. So I stacked the two subs in one corner, and that's were the great idea came from of some how running the pair as if it was one sub with dual drivers!
Considering everything is set correctly, volume, phase, low pass, etc.. Is there a way I could or should wire the subs together?
What mostly concerns me is this is an active unit, so the power amp in thing can cause some cancelation of some sorts, or any 101 unknown can be amiss here!
That's why I'll ask first, but would love to hear if it can be done, or is it common practice that I have not heard of, yet.
Thanks
Danny
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KeithL
Administrator 
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Post by KeithL on Dec 10, 2015 11:02:29 GMT -5
Whenever you have multiple drivers reproducing the same range of frequencies there will be some chance of interactions. However, two identical subs, stacked directly on top of each other, is about as close as you're going to get to minimizing this - so go for it! I would advise paralleling them together and treating them as a single unit with two drivers (just use a passive splitter). (And you'd want to set the controls - like level - the same.) (Putting two subs in different locations actually increases the likelihood of interactions. The reason it makes sense to do so is that it may smooth out the overall response - because any room modes or other anomalies present in one location probably won't be present in the other, so the overall bumps and dips tend to average out. Also note that, while maximizing room gain, a corner may not be the best location for a sub for other reasons - but WAF supersedes all - especially if she's armed with knitting needles  ) Hello folks, don't know if I should have just posted this over at the Stupid Question thread, but I'll ask here and see where it gets me. I purchased a pair of SVS of SB12-NSD sub over the Black Friday sale to put at opposite corners but it appears my Wife commandeer one of the corner for her knitting items. So I stacked the two subs in one corner, and that's were the great idea came from of some how running the pair as if it was one sub with dual drivers! Considering everything is set correctly, volume, phase, low pass, etc.. Is there a way I could or should wire the subs together? What mostly concerns me is this is an active unit, so the power amp in thing can cause some cancelation of some sorts, or any 101 unknown can be amiss here! That's why I'll ask first, but would love to hear if it can be done, or is it common practice that I have not heard of, yet. Thanks Danny |
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Post by djoel on Dec 10, 2015 12:27:02 GMT -5
Hey thanks for the nicely detailed response , and vote of confidence. Very happy it can be done, odd you don't hear/read more about doing so. I've seen multiple passive speakers wired in parallel as such but never subs. I have a splitter or two at home, I should just plugged them together and connect the one end to the XMC-1 and wallah? Of course with the trims, all and necessary intricacies in tacked on the subs If there are any guides write up with pictures  , links , or schematics I'll take them. Thanks again Danny |
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Post by unsound on Dec 10, 2015 12:34:56 GMT -5
I have it set up that way. I have 2 different subs stacked and that presented a lot of challenges with getting them to behave well around their high-pass filters (that would happen regardless of stacking). But, it should be much easier with identical subs.
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Post by djoel on Dec 10, 2015 14:12:37 GMT -5
Thanks Unsound...Any suggestion, method tools of the trade?  |
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Post by unsound on Dec 10, 2015 14:55:34 GMT -5
Since I was using 2 different subs, I used REW and minidsp to match phases and EQ them. Since you are using the same 2 subs, you may not need minidsp. The SB-12s have a phase dial that you should be able to use in conjunction with REW to get them aligned with each other. After that's done you can EQ them as 1 unit with your XMC-1 (using a passive splitter as Keith suggested)
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Post by jutta on Dec 10, 2015 15:00:32 GMT -5
My twin PSA XS30's. Best they've ever sounded!!!  |
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Post by jutta on Dec 10, 2015 15:01:47 GMT -5
Calibrated with Audyssey XT32 as dual subs
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Post by unsound on Dec 10, 2015 15:20:10 GMT -5
Calibrated with Audyssey XT32 as dual subs AFAIK, Audyssey XT32 actually sets phase/distance separately, but EQs them as 1 sub. |
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Post by jutta on Dec 10, 2015 15:21:52 GMT -5
XT32 Eq's as independent subs
The sole reason I purchased the X4000
That and they want $4000 for the XMC in Australia ....... If stock ever arrives. Not allowed to purchase from Emotiva due to Aust distributor who is yet to sell a single item as they have no stock. Been that way for several months now.
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Post by unsound on Dec 10, 2015 16:43:47 GMT -5
Please look at Chris' comment (pasted below for convenience) here: audyssey.zendesk.com/entries/20953442-SubEQ-HT-vs-MultEQ-XT32MultEQ XT32 is the flagship version of our technology to measure and correct room acoustical problems. Sub EQ HT is a method we came up with to deal with multiple subs. If you only have one sub then it's not in use. The idea is to first measure each sub separately, then apply delay and level settings so that the two subs are now time and level aligned. Then we ping them once more as "one" sub to derive the room correction filter. So, as per his comments, the EQing is done as 1 sub. The phase and level aligning are done separately. |
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Post by MusicHead on Dec 10, 2015 17:33:31 GMT -5
But with two identical stacked subs, is it even necessary to EQ them separately? The wavelength of the frequencies they reproduce is so long that I do not believe any EQ system would be able to tell them apart anyway.
Also, I do not know about the SVS, but the Rythmik I have has two set of inputs, LFE to be used with the sub output, and regular Line L/R if used in stereo with a preamp/receiver with no sub output. When using the LFE input, only the level control is active. The LP filter and phase control are bypassed, because the expectation is that the Bass Management of the preamp/receiver will take care of those settings.
If it is the same with the SVS, it makes really simple: just use a "Y" mono cable to split the LFE output from preamp/receiver to the LFE input of each sub, set the level knob at the same position for both and then set/run whatever bass management/room correction system you have as if they where one sub.
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Post by lionear on Dec 10, 2015 18:26:21 GMT -5
Only two? How about 12? www.genesisloudspeakers.com/g1p2.htmlIf you put multiple drivers in a line, then you can get a "comb effect" if the drivers have to handle frequencies that have a wavelength that's twice the distance between the drivers (center or driver to center of driver). But if you have a sub, there's not going to be any issue. I'd set the same frequency and level for both of them. |
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Post by unsound on Dec 10, 2015 18:40:16 GMT -5
In general, I think subs do need to be EQed together, after the phase and levels have been aligned. As far as subs stacked on top of each other, the room interaction can be very different across the distance of 1-2 feet. But, the levels should be easily matched. 1-2 ft is a minor phase difference given the relevant frequencies, but even with identical subs, their amps can have different delays especially those with DSP like the SVS. It might be ok to leave both phase settings at 0, but it certainly wouldn't hurt to measure and be sure.
AFAIK, SVS doesn't disable the phase dial when using the LFE input. Also, For SVS, the HP filter that prevents the driver from getting damaged is also active with LFE engaged. At least, I know it is for the vented subs where it kicks in at the port tuning frequency. Not so sure about the sealed sb-12. Considering that I bought one just now, I should educate myself on it.
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Deleted
Deleted Member
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Post by Deleted on Dec 10, 2015 19:14:20 GMT -5
Calibrated with Audyssey XT32 as dual subs AFAIK, Audyssey XT32 actually sets phase/distance separately, but EQs them as 1 sub. Are you able to do some rew sweeps of your subs ? I'm really curious to see how they interact with each other using Audyssey. |
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Post by jutta on Dec 10, 2015 19:40:52 GMT -5
AFAIK, Audyssey XT32 actually sets phase/distance separately, but EQs them as 1 sub. Are you able to do some rew sweeps of your subs ? I'm really curious to see how they interact with each other using Audyssey. Nope sorry I just know they sound much better like that than they did apart. I had to move them through necessity and probably just lucked it out!! |
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Post by yves on Dec 10, 2015 21:22:10 GMT -5
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)
, links , or schematics I'll take them.
