markus76 said:
Markus
Your data didn't prove a thing. Only that there was LF output in the center channel NOT that it was any different than what was in the left and right.
And when you set the AVR to "NO Sub" then the LFE is sent to the mains and hence gets to the DCX.
The JBL box REQUIRES the same signals as the DCX period.
An externally hosted image should be here but it was not working when we last tested it.
This is an example of a simple unbalanced to balanced circuit. If you look at the first opamp, you can add the L, C, and R inputs to tag two by having each one have it's own 33k padding resistor. Then all would be combined with no cross talk issues. While it's not necessary, and if you had to buy it, I wouldn't recomend it, you can make it with 3 single opamps (or two duals), and have the benefit of a little lower noise and no cross talk issues.
I've not used this DCX device, but I did use the older DEQ eq unit, and I had so many problems with it. The huge amounts of gain as well as the passive unbalanced to balanced and back again caused a lot of hiss. I think using this mentioned device would fix that maybe, but I would need to pick up a DCX and try it.
gedlee said:
Are you sure about that? A few posts ago you were sure that there is no low frequency content in the center channel at all. I feel better by looking at facts and real world data instead of adopting a belief.
Even if the low frequency content in each channel is the same, you might end up with the bass level being to low because you ignore the signal from C, LS, RS, LB, RB.
gedlee said:
That's correct. But what if the audio engineer decides to mix some low frequency content only to L and R? 3 to 5 of your sources will drop out of your low frequency array.
gedlee said:
As I said before I don't know what the BassQ does so I don't know what signal is best. I don't want to promote that box in any way. But the manual is pretty clear that you simply need the sub out which is available from every AVR.
Best, Markus
markus76 said:
Isn't that because it's a different approach which promotes high passing all speakers and not using them as additional LF sources.
I do think there is a problem with highpassing. In my opinion, based on my understanding of LF small room acoustics, you really want to deal with the LF problem at the transition point. That means either removing the mains from the LF equation completely or replicating the LF content across all the LF sources, including the mains. Highpassing the mains doesn't do the same thing as replicating the LF content across all LF sources unless it's high enough in frequency.
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.
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.
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
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
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.
"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.
gedlee said:
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
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.
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.
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.
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
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