XMC bass management

[bootman]

Not having any experience with gear having stereo sub outs I would like some clarification of how the signal is routed.

Is it possible to just run dual mono?
Is stereo subs only for 2ch sources?
What happens to the mono LFE channel info when running in stereo mode?
Since the subs are stereo by design, this means dual set of PEQs for each, correct?
What other settings are available?
Do we get independent xo and distance settings or are we assuming stereo subs are always up front with the mains?

Maybe we can list of the available sub setup options currently available?

[ludi]

I think most of the answers are in the manual.

[bootman]

Jul 19, 2014 9:27:49 GMT -5 ludi said:

I think most of the answers are in the manual.

I took a peak.
first question is -yes

the rest I don't see those specifics.
Can you tell me where you saw them?
I'll look again.

[LCSeminole]

Stereo subwoofer mode is not just for two channel. In stereo subwoofer mode, the left and right subwoofer channels each have their own set of 11 filters for P-EQ'ing.

[bootman]

Jul 19, 2014 9:58:20 GMT -5 LCSeminole said:

Stereo subwoofer mode is not just for two channel. In stereo subwoofer mode, the left and right subwoofer channels each have their own set of 11 filters for P-EQ'ing.

Are any other settings independant?
XO and distance for example?

Are these same options available in dual mono mode?
Or is there a dual mono mode?

[LCSeminole]

Page 14 of the manual.

XMC-1 is a full 7.2 channel surround sound processor, which means that it supports two
independent “stereo” subwoofers.
If you have two subwoofers, and configure the XMC-1 accordingly, then they will be configured
independently, and will operate in full stereo mode. In modes where Bass Management is active,
the Left Subwoofer will receive audio content at frequencies below the configured crossover
points for the Left Front, Left Surround, and Left Back Surround Speakers; the Right Subwoofer
will receive audio content at frequencies below the configured crossover point for the Right Front,
Right Surround, and Right Back Surround Speakers; both subwoofers will receive audio content
below the crossover frequency for the Center Channel, and both will receive content from the LFE
(low frequency effects) channel.
If your XMC-1 is configured for a single subwoofer, all of the content intended for both subwoofers
will be summed into a single monaural subwoofer output signal, which will be available at both
subwoofer outputs. Therefore, a single subwoofer may be connected to either output.
Note: Because some “localization” of subwoofer content may occur in some situations, stereo
subs should ideally be identical, and should be positioned symmetrically in the listening room.
If you have two very dissimilar subwoofers, or plan to place two or more subs in positions
that are NOT symmetrical - perhaps for purposes of evening out response variations caused
by major room modes, you may get better performance by configuring the XMC-1 to use “a
single mono sub”, and then feeding that monaural subwoofer signal to all of your subs. Using
asymmetrically placed stereo subwoofers, or dissimilar stereo subs, may result in imperfect
imaging and a sound stage that is less than optimal. This will depend on the specifics of your
subwoofers, your listening room, and your configuration.
Note: If you have two subwoofers, yet still prefer to have the XMC-1 treat them as a single sub,
simply configure the XMC-1 for a single mono subwoofer, then connect both of your subwoofers
to the two subwoofer outputs. In that configuration both subwoofer outputs will provide the
same signal. If you have more than two subwoofers, and wish to configure the XMC-1 to treat
them as a single sub, you may use one or more signal splitters on the XMC-1 subwoofer outputs
to provide extra outputs.

[bootman]

I went back and read that. Thanks!

In the settings are there options for distance(phase)and if so can each sub be set independently?
I couldn't find that info.

[AudioHTIT]

Jul 19, 2014 11:04:24 GMT -5 bootman said:

I went back and read that. Thanks!

In the settings are there options for distance(phase)and if so can each sub be set independently?
I couldn't find that info.

I think we found bootman's Achilles' heel, 'the manual'. I tease because I think you're one of the best researchers I've observed, always finding pertinent references and links when questions are asked, kudos to you in this regard.

As for the distance/phase question, if the two subs are EQ'd separately (which they are), how could it be otherwise. Just because the signal becomes mono wouldn't negate the need for independent EQ, distance, etc.

[LCSeminole]

Yes there is a distance setting and phase should be set on your subwoofer.

[bootman]

Jul 19, 2014 11:15:31 GMT -5 AudioHTIT said:

Jul 19, 2014 11:04:24 GMT -5 bootman said:

I went back and read that. Thanks!

In the settings are there options for distance(phase)and if so can each sub be set independently?
I couldn't find that info.

I think we found bootman's Achilles' heel, 'the manual'. I tease because I think you're one of the best researchers I've observed, always finding pertinent references and links when questions are asked, kudos to you in this regard.

As for the distance/phase question, if the two subs are EQ'd separately (which they are), how could it be otherwise. Just because the signal becomes mono wouldn't negate the need for independent EQ, distance, etc.

lol I guess you did get me there.

I assumed you could do that in stereo sub mode, I was just wondering if you ran dual mono would you still be able to do that or does it resort back to just one sub setting.
(single mono)
That part wasn't clear to me in the manual but is something someone can check on the unit itself.

Sorry about the confusion.

[srrndhound]

Jul 19, 2014 16:15:41 GMT -5 bootman said:

Jul 19, 2014 11:15:31 GMT -5 AudioHTIT said:

As for the distance/phase question, if the two subs are EQ'd separately (which they are), how could it be otherwise. Just because the signal becomes mono wouldn't negate the need for independent EQ, distance, etc.

lol I guess you did get me there.

I assumed you could do that in stereo sub mode, I was just wondering if you ran dual mono would you still be able to do that or does it resort back to just one sub setting.
(single mono)
That part wasn't clear to me in the manual but is something someone can check on the unit itself.

Sorry about the confusion.

I share your confusion. Page 14 of the manual says:
>>for purposes of evening out response variations caused by major room modes, you may get better performance by configuring the XMC-1 to use “a single mono sub”, and then feeding that monaural subwoofer signal to all of your subs<<

>>If you have two subwoofers, yet still prefer to have the XMC-1 treat them as a single sub,
simply configure the XMC-1 for a single mono subwoofer, then connect both of your subwoofers
to the two subwoofer outputs. In that configuration both subwoofer outputs will provide the
same signal.<<

I just does not make any distinction between splitting one sub output or using two, and if using two, there is the ability to adjust EQ, delay, gain. Probably an oversight in the manual and not the product. But would be good for someone to confirm based on actually checking the sub output signals.

[bootman]

For a while I thought I was the only one confused.
You put this question much more eloquently than I.

[adam631]

I have Definitive Technology Bp7000sc speakers with built in powered subs. My center and surrounds also have powered subs in them. What would be the best way to set up the bass management with the xmc-1?

Also should I use stereo sub setting? or the mono setting for sub output.
Andrew has reviewed the same system as I have before, so maybe he can chime in?

[edrummereasye]

This was posted recently in another thread:

www.nousaine.com/pdfs/Stereo%20Bass.pdf


I found it educational, and relevant...I recently acquired yet another sub (free!), bringing my total to 4...no two of which are identical, unfortunately. My main sub, in my LR system, is an old, "original" Outlaw LFM-1. The one I just acquired is, I don't even know the designation, but it's the "baby Outlaw" sub. I had purchased it for my mom and step-dad a few years back, they had asked me to put together a system for them...but my mom got tired of trying to have conversations while they were each sitting within a few feet of a surround speakerl, so... (no, she didn't ask my advice on that, which would've been "move one speaker and both chairs"...if she wasn't my mom, I would've said "shut up and watch the damn movie", lol!) Anyway...I considered that the "baby" Outlaw might be "voiced" similar to the larger one (more so than the Atlantic Tech sub I had as 2nd in the system), and that if nothing else, the controls would be the same. Then I read the following aricle. Both my subs are mid-wall in this house; I do have a corner nearby on one side (or 3/4 of one, since one wall is the staircase to go upstairs, so it gradually "opens" at the top, as you move away from the corner)...on the other side, the "corner" is formed by the front door and the coat closet (though we rarely use the front door, and my kids suck at hanging their coats up...hmmm...)

Anyway, while pondering, I realized that I could do "stereo" subs out from my XSP-1, instead of one from the UMC-200 and one from the XSP-1; and honestly, that opened up a whole can of worms. Is it really "stereo" when I'm in HT Bypass? No, at least I'm pretty sure "no", because the 200 is sending a mono signal to the XSP-1. So I'm guessing it's dual mono when the XSP is actually doint pre-amp duties (which is always music) and "stereo" when the UMC-200 is in control. Haven't had much listening time, I did notice the "baby" sub was running pretty hot, needed a lower volume setting than the other, but that's about the extent of what I've done to dial things in so far. Not sure what I'm going to do, if anything...hopefully my XMC-1 e-mail arrives soon enough to make it a non-issue, or at least a "basement" issue, lol...

Anyway, I found the article interesting, thought it might be relevant here, for those who haven't seen it before.

[jlafrenz]

Jul 19, 2014 18:24:15 GMT -5 srrndhound said:

Jul 19, 2014 16:15:41 GMT -5 bootman said:

lol I guess you did get me there.

I assumed you could do that in stereo sub mode, I was just wondering if you ran dual mono would you still be able to do that or does it resort back to just one sub setting.
(single mono)
That part wasn't clear to me in the manual but is something someone can check on the unit itself.

Sorry about the confusion.

I share your confusion. Page 14 of the manual says:
>>for purposes of evening out response variations caused by major room modes, you may get better performance by configuring the XMC-1 to use “a single mono sub”, and then feeding that monaural subwoofer signal to all of your subs<<

>>If you have two subwoofers, yet still prefer to have the XMC-1 treat them as a single sub,
simply configure the XMC-1 for a single mono subwoofer, then connect both of your subwoofers
to the two subwoofer outputs. In that configuration both subwoofer outputs will provide the
same signal.<<

I just does not make any distinction between splitting one sub output or using two, and if using two, there is the ability to adjust EQ, delay, gain. Probably an oversight in the manual and not the product. But would be good for someone to confirm based on actually checking the sub output signals.

Each sub can have it's own physical connection to the XMC-1. The XMC-1 can then treat them as individual subs or as "one sub". Setting the XMC-1 to mono would be the same as using a "Y" splitter. This is just done internally. Either way, both subs receive the same signal and EQ.

If you want to treat each sub individually, each of them would need to have their own physical connection and the subs set to stereo. This way each subwoofer can utilize independent PEQ.

You could have 2 subs in your room located in different areas and still treat them as a single sub. This way it uses the PEQ for the overall room response at your seating position.

[AudioHTIT]

Jul 19, 2014 22:41:53 GMT -5 jlafrenz said:

Jul 19, 2014 18:24:15 GMT -5 srrndhound said:

I share your confusion. Page 14 of the manual says:
>>for purposes of evening out response variations caused by major room modes, you may get better performance by configuring the XMC-1 to use “a single mono sub”, and then feeding that monaural subwoofer signal to all of your subs<<

>>If you have two subwoofers, yet still prefer to have the XMC-1 treat them as a single sub,
simply configure the XMC-1 for a single mono subwoofer, then connect both of your subwoofers
to the two subwoofer outputs. In that configuration both subwoofer outputs will provide the
same signal.<<

I just does not make any distinction between splitting one sub output or using two, and if using two, there is the ability to adjust EQ, delay, gain. Probably an oversight in the manual and not the product. But would be good for someone to confirm based on actually checking the sub output signals.

Each sub can have it's own physical connection to the XMC-1. The XMC-1 can then treat them as individual subs or as "one sub". Setting the XMC-1 to mono would be the same as using a "Y" splitter. This is just done internally. Either way, both subs receive the same signal and EQ.

If you want to treat each sub individually, each of them would need to have their own physical connection and the subs set to stereo. This way each subwoofer can utilize independent PEQ.

You could have 2 subs in your room located in different areas and still treat them as a single sub. This way it uses the PEQ for the overall room response at your seating position.

Really ... I would have thought the Y splitter (obviously) would give the same EQ, but that Mono mode would be separate EQ ... hmm?

[jlafrenz]

With my subs set to mono, I only have the option for 1 subwoofer in the PEQ configuration.

I don't really see the purpose of configuring subs individually when having them set to mono. When set to mono, the goal is to EQ the collective. This is my take on it anyway. Perhaps Keith will chime in and clarify.

[AudioHTIT]

Jul 19, 2014 22:54:29 GMT -5 jlafrenz said:

With my subs set to mono, I only have the option for 1 subwoofer in the PEQ configuration.

I don't really see the purpose of configuring subs individually when having them set to mono. When set to mono, the goal is to EQ the collective. This is my take on it anyway. Perhaps Keith will chime in and clarify.

I would think by their individual room position that they would each engage unique boundary reenforcement, but I'm sure they thought a lot about it.

[bootman]

Jul 19, 2014 22:58:52 GMT -5 AudioHTIT said:

Jul 19, 2014 22:54:29 GMT -5 jlafrenz said:

With my subs set to mono, I only have the option for 1 subwoofer in the PEQ configuration.

I don't really see the purpose of configuring subs individually when having them set to mono. When set to mono, the goal is to EQ the collective. This is my take on it anyway. Perhaps Keith will chime in and clarify.

I would think by their individual room position that they would each engage unique boundary reenforcement, but I'm sure they thought a lot about it.

If I have two mono subs in opposite ends, I would think at least adjusting distance/phase would be a useful feature.
Look's like stereo is the better choice if you are running dual subs and want to control each individually.

[jlafrenz]

Jul 19, 2014 22:58:52 GMT -5 AudioHTIT said:

Jul 19, 2014 22:54:29 GMT -5 jlafrenz said:

With my subs set to mono, I only have the option for 1 subwoofer in the PEQ configuration.

I don't really see the purpose of configuring subs individually when having them set to mono. When set to mono, the goal is to EQ the collective. This is my take on it anyway. Perhaps Keith will chime in and clarify.

I would think by their individual room position that they would each engage unique boundary reenforcement, but I'm sure they thought a lot about it.

They realistically will, but that doesn't mean they will perform the same at your listening position when they are both playing.

Think of it a bit differently. Pretend we are using a graph to show the response of each subwoofer. If you play a single subwoofer in a room you will get a certain response for your graph. Now regraph that same subwoofer with some other external noise in the same frequency range of your subwoofer. As the sub is playing and you now have included that external noise, your graph is going to change. With 2 subwooers, that external noise is the second subwoofer. Creating a flat response individually doesn't guarantee a flat response once both are playing together. If you play them both together to create your graph, once the EQ is applied, you should have a flat response with both of them playing. In my previous post I stated that I don't see the purpose in EQ'ing each sub separately. What I mean is that if you apply one EQ to both, I don't see it as different than EQ'ing them individually and then combining them. It is more work for the same result. I guess there could be a reason to individually EQ each sub and feed them a mono signal, but I just don't see it. As long as the response curve is flat (or set to whatever house curve you may have chosen) at your seating position.

Again, I won't claim to be an expert on room acoustics and subwoofer EQ, but from what I do know this how I see it working. Perhaps someone with a bit more expertise can jump in and give a more technical explanation. And if I am stating this incorrectly, please correct me.

I may also be misunderstanding what your intended use is or end goal.