Multiple Small Subs - Geddes Approach - Page 101 - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th April 2009, 04:10 PM   #1001
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally posted by markus76

... 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.

Best, Markus
Worst case its a hypothetical problem with no data to support your claim and best case it isn't a problem at all. So what if there is bass on only one of the channels, I don't see how that affects anything at all. Two of the three front channels don't have bass, but there wasn't any in the mix on those channels anyways - what's the problem? I don't get it.
  Reply With Quote
Old 17th April 2009, 04:31 PM   #1002
Banned
 
Join Date: May 2008
Location: Switzerland
Quote:
Originally posted by gedlee
Worst case its a hypothetical problem with no data to support your claim and best case it isn't a problem at all.
There's also no data to support the best case, right? And as long as there's no such data there'll always be a potential flaw in your solution.

Quote:
Originally posted by gedlee
So what if there is bass on only one of the channels, I don't see how that affects anything at all. Two of the three front channels don't have bass, but there wasn't any in the mix on those channels anyways - what's the problem? I don't get it.
The use of multiple subs makes only sense if ALL low frequency sources emit the SAME signal at ALL times. I really don't understand why you would want to challenge that.

Best, Markus
  Reply With Quote
Old 17th April 2009, 05:00 PM   #1003
diyAudio Member
 
Join Date: Jul 2008
Quote:
Originally posted by markus76


There's also no data to support the best case, right? And as long as there's no such data there'll always be a potential flaw in your solution.



The use of multiple subs makes only sense if ALL low frequency sources emit the SAME signal at ALL times. I really don't understand why you would want to challenge that.

Best, Markus
Isn't this all really just going to come down to "the proof is in the pudding" so to speak. I suggest Markus develop his ideas or use the JBL box when it comes out, and Earl can do his thing and then the market will determine.
  Reply With Quote
Old 17th April 2009, 05:04 PM   #1004
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally posted by markus76
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
Markus,

I am using a computer as a source, with a sound card that has balanced outputs. It's an Echo Audio MIA, which is considered a "pro" sound card.

Do you think it would be a good match for the Behringer gear?

Here's the problem that I am experiencing with my current set up:

I am using a Y-Cable to split the signal, and one side is going to a sub amp, the other is going to a second amp for the Summas.

When I run the Summas alone, it's as clear as a bell.

When I run both the subs and the Summas, the subs have a hum at about 60hz.

My guess is that a ground loop is being introduced, and it's introducing the hum into the subs?

Also, do you use amplifiers with balanced inputs?
  Reply With Quote
Old 17th April 2009, 05:24 PM   #1005
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally posted by markus76


There's also no data to support the best case, right? And as long as there's no such data there'll always be a potential flaw in your solution.



The use of multiple subs makes only sense if ALL low frequency sources emit the SAME signal at ALL times. I really don't understand why you would want to challenge that.

Best, Markus
Correct, there is no data either way, so the best we have is logic and analysis and neither favors you claims.

Your last sentence is not one that I agree with, which is perhaps, the issue. I see no reason to assume that the signals need to be identical. In fact, I have said many times that, in theory, the signals to each sub should be decorrelated, meaning NOT identical.

You seem to be digging in your heals and grabbing at straws just to "be right".
  Reply With Quote
Old 17th April 2009, 05:26 PM   #1006
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
Quote:
Originally posted by Patrick Bateman

When I run both the subs and the Summas, the subs have a hum at about 60hz.

My guess is that a ground loop is being introduced, and it's introducing the hum into the subs?

Ground loops to subs can be a real pain as ground loops are always hard to issolate. I usually end up cutting off the ground lug on the power plug. This seems to work most times. A little risky, but not that much.
  Reply With Quote
Old 17th April 2009, 05:39 PM   #1007
Banned
 
Join Date: May 2008
Location: Switzerland
Patrick,

the devices have to use the same ground if you're using a Y-cable.

Never ever cut off the ground lug! This is highly dangerous and even forbidden in some countries, e.g. Germany.

Best, Markus
  Reply With Quote
Old 17th April 2009, 05:44 PM   #1008
diyAudio Member
 
Join Date: Jul 2008
I have found these to work exceedingly well for hum

http://www.zzounds.com/item--EBTHUMX
  Reply With Quote
Old 17th April 2009, 05:47 PM   #1009
Banned
 
Join Date: May 2008
Location: Switzerland
Plugging all devices into one outlet is $70 cheaper.

Best, Markus
  Reply With Quote
Old 17th April 2009, 06:14 PM   #1010
gedlee is offline gedlee  United States
diyAudio Member
 
gedlee's Avatar
 
Join Date: Dec 2004
Location: Novi, Michigan
This isn't always possible and not always effective. Cutting the ground lug is not such a big deal, because the equipment is still grounded, just not through that lug. Its grounded through the signal wire shield. If a short to ground occurs it will conduct the current through the signal wires and then to ground, but this should still blow the fuse before any damage is done.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 12:05 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2