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Old 15th April 2009, 11:12 PM   #971
pjpoes is offline pjpoes  United States
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I understand, but the only thing we are trying to impact with the processor is the subs themselves, not the main speakers. I understand that some eq on the mains below the transition point might be better yet, but having it on the primary LF sources (subs) is fine, no?
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Old 15th April 2009, 11:14 PM   #972
pjpoes is offline pjpoes  United States
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the only way to send the LFE back to the mains is to turn off the subwoofer, this then would require a complete external "Bass management" system, as this is very non-typical. If this is in fact what Earl is suggesting, then yeah, you would need to have multiple processors (3 I believe) networked together along with RCA outs for all channels.
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Old 15th April 2009, 11:31 PM   #973
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pjpoes, not sure that I understand what you're saying.

As soon as you run the mains full range and make them part of the multisub calibration then you have to make sure that they also reproduce coherent low frequency content with each and every source material. But this is something a DVD or Blu-ray doesn't deliver and there's no AVR (I know of) that has this kind of bass management. You can only mix the low frequency content of all channels to the LFE and output that from the sub out, but you can't mix that back to the other speakers. So every time the LFE carries a signal, the mains are no longer part of the low frequency array and therefore the multisub calibration won't work anymore.

The easiest solution would be to apply a HP to the mains and make only the subs part of the calibration.

Best, Markus
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Old 15th April 2009, 11:36 PM   #974
amiklos is offline amiklos  United States
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Quote:
Originally posted by pjpoes
the only way to send the LFE back to the mains is to turn off the subwoofer, this then would require a complete external "Bass management" system, as this is very non-typical. If this is in fact what Earl is suggesting, then yeah, you would need to have multiple processors (3 I believe) networked together along with RCA outs for all channels.
I don't think that is what Earl is suggesting at all.

It seems rather simple. Set the mains to run full range. That sends LF content to the front L&R preouts. Use the L&R preouts and sum them in the DCX. Send that summed signal to the various subs, using the processing within the DCX on each sub channel.

AVR->DCX->sub amps->subs

If people are that concerned with the center channel LF info they can put a mixer ahead of the DCX to combine the required signal prior to the DCX input, but that whole exercise seems like a solution in search of a non-existent problem.
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Old 15th April 2009, 11:36 PM   #975
pjpoes is offline pjpoes  United States
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Markus, I agree with what your saying. What I'm saying is that I don't think it's that important if the mains aren't a part of this optimization. I thought using the mains as LF sources is really somewhat incidental. If you make the mains full range, you can still mix their LF content into the sub channel and optimize that.

However, if you really felt it was important to mix all of the bass content into all speakers and subs, the only way I can know of to do this would be through external speaker management. It would be a lot more complicated, and I would somewhat question it's value.
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Old 15th April 2009, 11:40 PM   #976
pjpoes is offline pjpoes  United States
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Quote:
Originally posted by amiklos


I don't think that is what Earl is suggesting at all.

It seems rather simple. Set the mains to run full range. That sends LF content to the front L&R preouts. Use the L&R preouts and sum them in the DCX. Send that summed signal to the various subs, using the processing within the DCX on each sub channel.

AVR->DCX->sub amps->subs

If people are that concerned with the center channel LF info they can put a mixer ahead of the DCX to combine the required signal prior to the DCX input, but that whole exercise seems like a solution in search of a non-existent problem.
Again, the only way to get the LFE signal would be to turn off the subwoofer in the processor, so to do as you say would require doing this. While that accomplishes the goal for all the LF content that would exist (LFE+LF of mains), Markus is right that different LF content is sent to different channels. While this was less true in the old days, modern media has the room and ability to have Discrete full range channels, and studios are using it. This would mean that you would need to output the L,C,R, SR, SL to an outboard set of DCX processors networked together.
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Old 15th April 2009, 11:42 PM   #977
gedlee is offline gedlee  United States
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Markus

You are wrong about the JBL box. It requires preamp outputs on the AVR just like the DCX does. Its no different in that regard. It ASSUMES a JBL AVR.

Matt

I don't follow why you say three processors are needed. Sum all three front channels (set surrounds to "small") with the "No Sub" setting in the receiver and you will have ALL LF (L, R, C and LFE) output as one signal. NOW, if you can only sum two (like in the DCX) THEN, IF there is DIFFERENT content on the channel that is omitted there could be a problem. BUT, this is rare to nonexistant. IF the LF signal is the same for the three front channels (as it usually is) then there is no problem. This is at least the third time that I have said this.

I would be leary of summing using Y-RCA as the output buffering is unlikely to be able to handle this. I would just take the signal off of the speaker out using a resistor bridge as this would be quite easy.
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Old 15th April 2009, 11:49 PM   #978
pjpoes is offline pjpoes  United States
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Ah I guess I was over complicating this, we aren't trying to process the mains back again.

Ok so this makes more sense now, I was very fixated on having all 5 channels as full range and taking all this content and redistributing the differential LF content to all channels equally, including the LFE.

Differnt LF content is sent to different channels sometimes, but I think you are right Dr. Geddes, as I said earlier, I was told that they are often sending a lot LF content to all channels to accomplish the need for more output at those channels, it's not really like "stereo bass" or I guess really, surround bass. If they were doing surround bass and you needed to send this information back to all the speakers, then you would need to do as I said, use multiple networked processors.

As far as combining the RCA outputs in a fashion that doesn't cause cross talk issues, a very simple circuit can be built with 4 dual opamps and a small handful of capacitors and resistors. It would create a 3 into 1 signal, buffered (could be balanced too for going into the DCX), and would probably be the most ideal.
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Old 15th April 2009, 11:55 PM   #979
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Quote:
Originally posted by gedlee
You are wrong about the JBL box. It requires preamp outputs on the AVR just like the DCX does. Its no different in that regard. It ASSUMES a JBL AVR.
Which box are you talking about? The BassQ? Didn't you read the manual?

"Although the
system has been designed to work
with the rest of the Performance Series
system, including AV1 and AVA7,
the unit can be used in almost any
system and can improve the in-room
response of almost any installation."

"There are two subwoofer inputs.
If using an AV1 processor or other
processor that has a single subwoofer
or LFE output
, connect the subwoofer
output to the Left input and set the input
mode to Mono on the front panel of the
JBL BassQ unit. [...] If you are using
a preamp/processor such as the AV2,
or an AVR that has stereo subwoofer
outputs
, connect the left and right
inputs and set the mode to Stereo on
the front panel of the JBL BassQ unit."

Quote:
Originally posted by gedlee I don't follow why you say three processors are needed. Sum all three front channels (set surrounds to "small") with the "No Sub" setting in the receiver and you will have ALL LF (L, R, C and LFE) output as one signal.
But you still don't have the LFE in the speakers.

Quote:
Originally posted by gedlee NOW, if you can only sum two (like in the DCX) THEN, IF there is DIFFERENT content on the channel that is omitted there could be a problem. BUT, this is rare to nonexistant. This is at least the third time that I have said this.
What more proof do you need than real world data I posted??

Markus
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Old 15th April 2009, 11:55 PM   #980
amiklos is offline amiklos  United States
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Quote:
Originally posted by pjpoes


Again, the only way to get the LFE signal would be to turn off the subwoofer in the processor, so to do as you say would require doing this. While that accomplishes the goal for all the LF content that would exist (LFE+LF of mains), Markus is right that different LF content is sent to different channels. While this was less true in the old days, modern media has the room and ability to have Discrete full range channels, and studios are using it. This would mean that you would need to output the L,C,R, SR, SL to an outboard set of DCX processors networked together.

I have a hard time believing that there is much unique LF content sent to those surround channels, at least not enough to justify the complexity of the system being suggested (yes I saw Markus's data). While in theory there may be something that gets missed, what is the practical impact in the course of 99% of listening? Studios aren't really expecting the average consumer to have 5hz-20khz reproduction on each channel are they?

Even if you did want to combine all the LF info from all the channels, what prevents you from using a mixer to sum sets of channels ahead of the DCX rather than needing several DCX units? The goal is still to send the same LF info to all subs (with requisite processing in place), correct?
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