# Setting up 2 subs



## bclare (Dec 22, 2009)

I am looking for thoughts on the best way to setup 2 subs.
I am using a HTPC with VST plugins to perform bass management, channel routing, delays, room correction. Hence I have complete flexibility in how I connect the 2 subs.

The 2 main options I am considering are:
Send the same signal as the single sub to the second sub, with a correct delay and attenuate both signals by 3dB.
Or send the left channels to one sub and the right channels to the other sub, lfe to both subs attenuated by 3dB and correct delays.


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## moggieuk (Mar 26, 2008)

Hi Brad,

You haven't specified how or where your subs are arranged (or are you asking how to use REW to obtain best placement and then equalize?). I'm not expert but am experimenting with EQing two subs right now and so am interested in what the experts suggest for you. For my setup I have no way to move subs (front is an IB) so I have subs placed centrally on the front and rear walls which is one of the optimum placements for two subs. In theory a delayed and correctly phased signal to the rear sub can help elevate some room modes...


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## Wayne A. Pflughaupt (Apr 13, 2006)

I’d set the proper delays for each sub, and then equalize them in tandem – i.e. as if one sub, with a single set of filters.

Regards,
Wayne


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## bclare (Dec 22, 2009)

At the moment I have a single seaton sound submersive. I have used the RTA mode of REW to find the best placement around the perimeter of the room. I have reasonable flexibility in placement and the best spot seems to be to the right of the front left speaker.
I have used DRC to equalise all the speakers.

The second sub is on order and was asking what the best way to connect 2 subs is.

Is there any value in sending front left to one and front right to the other? As in a 4-way speaker system?

Or does sending the same signal to both subs give you the smoothest response?


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## Wayne A. Pflughaupt (Apr 13, 2006)

> Is there any value in sending front left to one and front right to the other? As in a 4-way speaker system?


Typically, no. Most stereo program material has identical bass content in both channels. Programs, music etc. with true stereo bass is few and far between. This is why most receivers have only a mono subwoofer send.

Regards,
Wayne


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## bclare (Dec 22, 2009)

Do you know if the newer receivers/processors with dual sub outs (eg integra 80.1) have the same signal sent to each sub (with different delays and gains)?


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## Moonfly (Aug 1, 2008)

bclare said:


> Do you know if the newer receivers/processors with dual sub outs (eg integra 80.1) have the same signal sent to each sub (with different delays and gains)?


Unless the source material is specifically encoded with dual subwoofer channels, then yes thats what happens. LFE is typically a single mono channel. Its entirely possible music will send different bass to each sub it depends on the source. In short, this is dictated by the source material more than the processor or AVR etc.


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## Wayne A. Pflughaupt (Apr 13, 2006)

> Do you know if the newer receivers/processors with dual sub outs (eg integra 80.1) have the same signal sent to each sub (with different delays and gains)?


If that is the case, then I would expect that information to be in the manual. Consider no comment on the subject to be a “no.”

Regards,
Wayne


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## Trick McKaha (Oct 7, 2009)

If you try it both ways, I'd be interested to know if you hear a difference.


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## koyaan (Mar 2, 2010)

In my setup I have all 3 subs behind the listening position using the same signal and delays. A fellow I used to know, however, used stereo subs in the front of the room with front speakers set to large in his preamp and the subs wired between the preamp out and amp in of his main channels. It sounded great, but, of course, requires subs with RCA hi/lo pass capabilities, something I do not have.


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## Owen Bartley (Oct 18, 2006)

I think if you have pretty uniform bass from your current single location, you might want to co-locate or stack the subs if it's an option. If you've already found a good sweet spot, adding the second would get you more volume and more headroom, and you wouldn't have to worry about cancellation and other interference between the two. On the other hand, if you do have some difference in sound throughout the room, finding a second sweet spot and feeding it the same EQ'ed signal like Wayne suggested could work well for you.


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## ojojunkie (Jun 23, 2010)

From my readings posted by those with multiple subs. If possible to get identical subs with similar characteristics for easy integration and setting-up.For 2 subs with dissimilar characteristics – Sub1 goes down to 16 Hz while Sub2 goes down to 24 Hz – and you send the same signal to the 2 subs, using a Y-cable. Both subs will be reproducing the same signal but for signals from 18 to 24 Hz, only Sub1 will be heard. That means that the SPL will be cut in half for those signals. You’ll still be able to hear the deep bass but it will be softer and have less impact. if we assume that Sub1 has a flat frequency response (accurate) while the frequency response of Sub2 jumps all over the place. You will get an average response quality that is in-between the 2 subs.


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## Owen Bartley (Oct 18, 2006)

That would make sense. So ideally if you are using 2 different subs and wanted to flatten your response, you could use EQ to either increase Sub1's output below 24Hz or decrease Sub1 and Sub2's output above 24Hz so you wouldn't have large differences in output below Sub2's cutoff, but you would still have the benefits of 2 subs (like filling the room better if in different locations).


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