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Old 16th April 2009, 08:39 PM   #991
gedlee is offline gedlee  United States
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Markus

Now that I've had a chance to rest, I'll come back to your discussion.

First you have to understand that in "No Sub" mode all LFE is routed equally to any speaker that is "large". If the surrounds are set "small" then their LF signals are likewise routed to the "large" LCR. Now in the DCX, if the LR signals are summed then ALL LF content is present, EXCEPT any LF content that is unique to the center channel. I claim that this "unique" center LF content is non-existant, but very rare at the outside - it will always be the same as the LR LFs. Hence, there is no LF signals that do not get to the subs.

Now a question that you asked before IS very relevent. When setting up the subs, does the "main" signal contain the center channel or not. THAT is a relavent concern since it can't be done both ways. I haven't even tried it both ways. I optimized for stereo by using just the LR signal in the "mains" signal. When there is a center channel then its like adding a sixth sub to the mix, and I don't expect that this would yield a very appreciable difference. Certainly not one that I have ever detected.
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Old 16th April 2009, 09:10 PM   #992
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Earl,

that's all correct and there's an additional problem: uncorrelated low frequency content in only one or two of the 3 front channels.

<broken record>Apply a highpass by running all speakers as "small" and optimize the AVR's sub out. This will deal with ANY source signal and any cheap AVR will work.</broken record>

Best, Markus
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Old 16th April 2009, 09:13 PM   #993
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Quote:
Originally posted by markus76
Earl,

that's all correct and there's an additional problem: uncorrelated low frequency content in only one or two of the 3 front channels.

<broken record>Apply a highpass by running all speakers as "small" and optimize the AVR's sub out. This will deal with ANY source signal and any cheap AVR will work.</broken record>

Best, Markus
Don't you then lose some of the advantage of having some upper bass from the Summa/Nathan/Abbeys?
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Old 16th April 2009, 09:23 PM   #994
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randybes, to a certain extend you will loose the speakers as additional low frequency sources, yes. But you'll gain a controlled setup that works with any source material and is simple to set up.

The real question would be: are three subs enough?

Best, Markus
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Old 17th April 2009, 02:45 AM   #995
gedlee is offline gedlee  United States
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Markus

"an additional problem: uncorrelated low frequency content in only one or two of the 3 front channels"

Except that I don't agree. That is ONLY true if its the center channel and there is a trivial solution - just sum ALL three channels. If all three front channels are summed then it makes no difference if the signals are uncorrelated or not.

Running all speakers as "small" adds nothing but looses the multiple sources from the mains.

I simply do not agree with your assesment.
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Old 17th April 2009, 03:42 AM   #996
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Originally posted by gedlee
I simply do not agree with your assesment.
You made that more than clear. But you still have a problem if there's bass on only one of the front channels. Under that circumstances 2 of the 3 front channels won't act as low frequency sources anymore. We both don't know if this is a real problem because there simply is no data. My conclusion is to use a setup that can handle any source signal—high pass filtered mains and surrounds.

Best, Markus
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Old 17th April 2009, 01:20 PM   #997
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In wanting to do this method, I do have one unique problem (not a major one) in that I use a Pre-pro with separate amps, not a receiver. I only have the one set of pre-outs for surround, but I realized that I also have 2nd room pre-outs which are a 2-channel mix down. Can anyone think of any reason why this wouldn't be the perfect solution for me (I'm assuming it mixes all of the channels including the LFE into the 2nd room output). If I'm thinking correctly, not only do I get to hook up without using y-adapters, avoid any chance of channel separation issues, but also would deal with the problem Markus brings up.
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Old 17th April 2009, 01:28 PM   #998
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Yes, that would eliminate the need of a separate mixer to sum all 7 channels. Make sure the volume for both zones is linked.
The potential problem with single low frequency events in only one of the channels remains.

Best, Markus
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Old 17th April 2009, 02:00 PM   #999
pjpoes is offline pjpoes  United States
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Markus, I saw that you tested the signals before, if you want to see if your concern is warranted, why don't you look at the waveform of all the channels during the same parts of the movie. If that doesn't come up with anything, look for parts with hard effects steering, and then see if the LF content is different.

What problems are you having with the DcX? As I mentioned earlier, I had some horrible issues with the DEQ, and I've been reluctant to ever try one of these devices again because of that. There was simply no way for me to get it balanced right without causing such low input levels as to cause "loss of bit resolution" causing the onset of audible distortion during low level signals. It introduced a ton of hiss that I simply could not get rid of no matter what I did. While I would like to try this device, and I have used really good DSP devices from more expensive companies, I'm still really reluctant to use this one.
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Old 17th April 2009, 02:38 PM   #1000
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pjpoes,

I would love to take a closer look at multichannel signals but haven't found an easy way to do it yet.

I own a DCX and use it in my 2 channel setup now for years.
The DCX has basically the same problem as the DEQ has. It's built for PA and not for home use. The max. input level is 22dBu which is much more than consumer electronics can deliver. You will "loose bits". If you're running the DCX behind the volume control then you'll further loose bits. But there are 24bits@96kHz so this might not be a problem at all.

The hiss was probably not a problem with the unit but with unbalanced cabling. That's why I run my whole setup balanced. Hiss can also be caused by a hardware bug of the DCX. It becomes audible only when using the digital in.

Best, Markus
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