16 replies to this topic

[Houston]

I am hopping some of you audiophiles can help me solve my current issue.  Here is a little background on the problem.  

I am using a Soundcraft E8 mixer connected to a pioneer 7400 DVD player.  From my mixer I am running XLR cables to a DBX Driverack PA.  I used the wizard to setup my DRPA and was using (2) ce4000 amps.  Each amp was used to push the following: (1) JBL sr4733x and (1) JBL sr4719x.  During DVD playback, when a loud scene such as a train or thunder began in the movie the amps would shut down for about 10 seconds and then turn back on.
I figured that this was due to overheating and I did not have enough watts to push these four speakers.  
After speaking with an employee at Guitar center, he advise me that I should add another ce4000 to eliminate the problem.  

Problem not solved! Still shuts down for 10seconds and then turns back on.

The current setup is as follows.
(1) ce4000 pushes both the left and right sr4733x speakers.  I then have the other (2) ce4000's pushing each sr4719x each in mono.  

I have the drpa set up as follows:
High output on the drpa is split using a xlr splitter and plugged into the ce4000 channel 1 and channel 2.  This pushes the 4733x's .
I then have each low output from the drpa connected to channel 1 on the other 2 ce4000's  These two amps push my 4719x's.  
The crossover is set at 40Hz - 90Hz for Lows and the Highs start at 118 Hz.

I am running banana plugs out of the binding post to the speakers.  The 4719's are set in passive mode and I then use a 6' speakon jumper to feed the 4733's.

I have great sound in the current configuration but I am still getting having the same problem of shutting down, even after the addition of another ce4000.

Do I need to add more power to the 4733's?  Do I need to reconfigure my setup? It is hard to imagine that (3) ce4000's will not push these JBL's.
Please help.

[guyofsound]

I am hopping some of you audiophiles can help me solve my current issue.  Here is a little background on the problem. 

I am using a Soundcraft E8 mixer connected to a pioneer 7400 DVD player.  From my mixer I am running XLR cables to a DBX Driverack PA.  I used the wizard to setup my DRPA and was using (2) ce4000 amps.  Each amp was used to push the following: (1) JBL sr4733x and (1) JBL sr4719x.  During DVD playback, when a loud scene such as a train or thunder began in the movie the amps would shut down for about 10 seconds and then turn back on.
I figured that this was due to overheating and I did not have enough watts to push these four speakers. 
After speaking with an employee at Guitar center, he advise me that I should add another ce4000 to eliminate the problem. 

Problem not solved! Still shuts down for 10seconds and then turns back on.

The current setup is as follows.
(1) ce4000 pushes both the left and right sr4733x speakers.  I then have the other (2) ce4000's pushing each sr4719x each in mono. 

I have the drpa set up as follows:
High output on the drpa is split using a xlr splitter and plugged into the ce4000 channel 1 and channel 2.  This pushes the 4733x's .
I then have each low output from the drpa connected to channel 1 on the other 2 ce4000's  These two amps push my 4719x's. 
The crossover is set at 40Hz - 90Hz for Lows and the Highs start at 118 Hz.

I am running banana plugs out of the binding post to the speakers.  The 4719's are set in passive mode and I then use a 6' speakon jumper to feed the 4733's.

I have great sound in the current configuration but I am still getting having the same problem of shutting down, even after the addition of another ce4000.

Do I need to add more power to the 4733's?  Do I need to reconfigure my setup? It is hard to imagine that (3) ce4000's will not push these JBL's.
Please help.

[guyofsound]

I am hopping some of you audiophiles can help me solve my current issue.  Here is a little background on the problem. 

I am using a Soundcraft E8 mixer connected to a pioneer 7400 DVD player.  From my mixer I am running XLR cables to a DBX Driverack PA.  I used the wizard to setup my DRPA and was using (2) ce4000 amps.  Each amp was used to push the following: (1) JBL sr4733x and (1) JBL sr4719x.  During DVD playback, when a loud scene such as a train or thunder began in the movie the amps would shut down for about 10 seconds and then turn back on.
I figured that this was due to overheating and I did not have enough watts to push these four speakers. 
After speaking with an employee at Guitar center, he advise me that I should add another ce4000 to eliminate the problem. 

Problem not solved! Still shuts down for 10seconds and then turns back on.

The current setup is as follows.
(1) ce4000 pushes both the left and right sr4733x speakers.  I then have the other (2) ce4000's pushing each sr4719x each in mono. 

I have the drpa set up as follows:
High output on the drpa is split using a xlr splitter and plugged into the ce4000 channel 1 and channel 2.  This pushes the 4733x's .
I then have each low output from the drpa connected to channel 1 on the other 2 ce4000's  These two amps push my 4719x's. 
The crossover is set at 40Hz - 90Hz for Lows and the Highs start at 118 Hz.

I am running banana plugs out of the binding post to the speakers.  The 4719's are set in passive mode and I then use a 6' speakon jumper to feed the 4733's.

I have great sound in the current configuration but I am still getting having the same problem of shutting down, even after the addition of another ce4000.

Do I need to add more power to the 4733's?  Do I need to reconfigure my setup? It is hard to imagine that (3) ce4000's will not push these JBL's.
Please help.

I have a similar system to this. I use it to do sound for rooms with up to 400 people in it. Are you using it for home theater? It seems to be a little much for that but anyway.

Word of advise if you don't want to spend good money after bad money find a better place to buy gear. Guitar Center is known for having people who don't know exactly what they are talking about. Most of them are Djs or studio engineers working for $10- 15 an hour, but anyway that is beside the point.

How loud are you listening to your system and what is shutting down. If the subs are shutting down I would imagine it would be because you didn't set the drive rack up right . The wizard on the drive rack is not as easy as people think it is and remember it is only a guide line, it is not always the best settings for the situation.

I have 4 of these myself. The wizard doesn't tell you to set the limiters or the compressor, there is also a button on the back of unit -10 and +4 you have to see which one works for you (probably +4). You need to look at the whole picture before buying more stuff, it'll put you in the poor house if you don't. I wouldn't buy anymore stuff. The amps are enuff to do the job. the x-over is fine you probably need to tweek it thou.

Also if you used the rta on the front with the mic they sell for it. The auto Eq also adds a lot of lows to the system that you cannot hear remember to use your ear. Is the speakers bottoming out are they blowing. I didn't hear you say they were blowing depending on what exactly you are using it for (how many people listening to the train?) Nobody can diagnose a system without all the info.

The other thing you might want to make sure the fans are working they are variable and turn on with heat.

All in all it seems like you would have a nice system. (If set up right.)

Hope this helps a little.

Jim

Good luck and may the force be with you.

[Houston]

I have a similar system to this. I use it to do sound for rooms with up to 400 people in it. Are you using it for home theater? It seems to be a little much for that but anyway.

No, I am doing outdoor cinema productions.


Word of advise if you don't want to spend good money after bad money find a better place to buy gear. Guitar Center is known for having people who don't know exactly what they are talking about. Most of them are Djs or studio engineers working for $10- 15 an hour, but anyway that is beside the point.

How loud are you listening to your system and what is shutting down. If the subs are shutting down I would imagine it would be because you didn't set the drive rack up right . The wizard on the drive rack is not as easy as people think it is and remember it is only a guide line, it is not always the best settings for the situation.

I am not turning the system up all the way.  It still seems to have plenty of headroom.

I have 4 of these myself. The wizard doesn't tell you to set the limiters or the compressor, there is also a button on the back of unit -10 and +4 you have to see which one works for you (probably +4). You need to look at the whole picture before buying more stuff, it'll put you in the poor house if you don't. I wouldn't buy anymore stuff. The amps are enuff to do the job. the x-over is fine you probably need to tweek it thou.

Also if you used the rta on the front with the mic they sell for it. The auto Eq also adds a lot of lows to the system that you cannot hear remember to use your ear. Is the speakers bottoming out are they blowing. I didn't hear you say they were blowing depending on what exactly you are using it for (how many people listening to the train?) Nobody can diagnose a system without all the info.

All of the speakers shut down, not just the subs. The system only shuts down when a loud scene plays during the DVD.  

The other thing you might want to make sure the fans are working they are variable and turn on with heat.

[COLOR=red]Not sure how to check for this

All in all it seems like you would have a nice system. (If set up right.)

Any advise on a setup for what I have?

Hope this helps a little.

You stated you use the drpa.  Could you give me a rundown of your settings?  I do use a RTA mic with my system.  The bass sounds fine, almost too much.  The mids and highs do not sound that loud.  I am just confused on why all of the speakers shut down, even the (2) 4719's that are being pushed with (2) ce4000's.

[guyofsound]

I have a similar system to this. I use it to do sound for rooms with up to 400 people in it. Are you using it for home theater? It seems to be a little much for that but anyway.

No, I am doing outdoor cinema productions.


Word of advise if you don't want to spend good money after bad money find a better place to buy gear. Guitar Center is known for having people who don't know exactly what they are talking about. Most of them are Djs or studio engineers working for $10- 15 an hour, but anyway that is beside the point.

How loud are you listening to your system and what is shutting down. If the subs are shutting down I would imagine it would be because you didn't set the drive rack up right . The wizard on the drive rack is not as easy as people think it is and remember it is only a guide line, it is not always the best settings for the situation.

I am not turning the system up all the way.  It still seems to have plenty of headroom.

I have 4 of these myself. The wizard doesn't tell you to set the limiters or the compressor, there is also a button on the back of unit -10 and +4 you have to see which one works for you (probably +4). You need to look at the whole picture before buying more stuff, it'll put you in the poor house if you don't. I wouldn't buy anymore stuff. The amps are enuff to do the job. the x-over is fine you probably need to tweek it thou.

Also if you used the rta on the front with the mic they sell for it. The auto Eq also adds a lot of lows to the system that you cannot hear remember to use your ear. Is the speakers bottoming out are they blowing. I didn't hear you say they were blowing depending on what exactly you are using it for (how many people listening to the train?) Nobody can diagnose a system without all the info.

All of the speakers shut down, not just the subs. The system only shuts down when a loud scene plays during the DVD. 

The other thing you might want to make sure the fans are working they are variable and turn on with heat.

[COLOR=red]Not sure how to check for this

All in all it seems like you would have a nice system. (If set up right.)

Any advise on a setup for what I have?

Hope this helps a little.

You stated you use the drpa.  Could you give me a rundown of your settings?  I do use a RTA mic with my system.  The bass sounds fine, almost too much.  The mids and highs do not sound that loud.  I am just confused on why all of the speakers shut down, even the (2) 4719's that are being pushed with (2) ce4000's.

You kind of have me stumped on all the speakers shutting down but here are what I use for settings. 1st of all start with the your setting for 2 way bi-amp x-over point 100hz butter worth subs turned up to -8 make sure you set the roll off on the bottom to because you don't need anything under 35 hz (butterworth setting) tops I use the 4732 models with the 12" speakers but I am asumming that it would be fine to use the same setting at 100 hz butterworth set at -2.2 db.

Then go into your eq section and flatten it the eq that the mic gives probably turned all of the low end up all the way, don't be surprised at this it's a microphone that cost $150 not exactly what you call flat.

Start with your parametric eq start with the low eq bump up  60 hz + 4db to get some rumble with a q of 3.0.  Then move to the high eq take some of the 250 hz   -4 out of the tops about the same as subs they get a little honky because thay are 15" speakers turn a little of 1000 hz down about 2 db with a q of 1.5.

When you get done with that move on to your limiting and compressors, make sure it is on right arrow to next page set your compressor at inf - 1 this will insure you can't turn it up to loud but you can play with this after to make sure you don't over compress then hit the compressor button again until you see the limiting section set the limiter on lows to 0 db over easy 3 - highs the same

You don't need the delay or sub-harmonic section. Limiting will hit when you turn up the system but will insure it runs safely.

Give these settings a try if you need further assistance I will check back later.

Jim

[guyofsound]

I have a similar system to this. I use it to do sound for rooms with up to 400 people in it. Are you using it for home theater? It seems to be a little much for that but anyway.

No, I am doing outdoor cinema productions.


Word of advise if you don't want to spend good money after bad money find a better place to buy gear. Guitar Center is known for having people who don't know exactly what they are talking about. Most of them are Djs or studio engineers working for $10- 15 an hour, but anyway that is beside the point.

How loud are you listening to your system and what is shutting down. If the subs are shutting down I would imagine it would be because you didn't set the drive rack up right . The wizard on the drive rack is not as easy as people think it is and remember it is only a guide line, it is not always the best settings for the situation.

I am not turning the system up all the way.  It still seems to have plenty of headroom.

I have 4 of these myself. The wizard doesn't tell you to set the limiters or the compressor, there is also a button on the back of unit -10 and +4 you have to see which one works for you (probably +4). You need to look at the whole picture before buying more stuff, it'll put you in the poor house if you don't. I wouldn't buy anymore stuff. The amps are enuff to do the job. the x-over is fine you probably need to tweek it thou.

Also if you used the rta on the front with the mic they sell for it. The auto Eq also adds a lot of lows to the system that you cannot hear remember to use your ear. Is the speakers bottoming out are they blowing. I didn't hear you say they were blowing depending on what exactly you are using it for (how many people listening to the train?) Nobody can diagnose a system without all the info.

All of the speakers shut down, not just the subs. The system only shuts down when a loud scene plays during the DVD. 

The other thing you might want to make sure the fans are working they are variable and turn on with heat.

[COLOR=red]Not sure how to check for this

All in all it seems like you would have a nice system. (If set up right.)

Any advise on a setup for what I have?

Hope this helps a little.

You stated you use the drpa.  Could you give me a rundown of your settings?  I do use a RTA mic with my system.  The bass sounds fine, almost too much.  The mids and highs do not sound that loud.  I am just confused on why all of the speakers shut down, even the (2) 4719's that are being pushed with (2) ce4000's.

You kind of have me stumped on all the speakers shutting down but here are what I use for settings. 1st of all start with the your setting for 2 way bi-amp x-over point 100hz butter worth subs turned up to -8 make sure you set the roll off on the bottom to because you don't need anything under 35 hz (butterworth setting) tops I use the 4732 models with the 12" speakers but I am asumming that it would be fine to use the same setting at 100 hz butterworth set at -2.2 db.

Then go into your eq section and flatten it the eq that the mic gives probably turned all of the low end up all the way, don't be surprised at this it's a microphone that cost $150 not exactly what you call flat.

Start with your parametric eq start with the low eq bump up  60 hz + 4db to get some rumble with a q of 3.0.  Then move to the high eq take some of the 250 hz   -4 out of the tops about the same as subs they get a little honky because thay are 15" speakers turn a little of 1000 hz down about 2 db with a q of 1.5.

When you get done with that move on to your limiting and compressors, make sure it is on right arrow to next page set your compressor at inf - 1 this will insure you can't turn it up to loud but you can play with this after to make sure you don't over compress then hit the compressor button again until you see the limiting section set the limiter on lows to 0 db over easy 3 - highs the same

You don't need the delay or sub-harmonic section. Limiting will hit when you turn up the system but will insure it runs safely.

Give these settings a try if you need further assistance I will check back later.

Jim

The other thing the fans are on the back of the amps if they are moving they are on.

jim

[Houston]

The other thing the fans are on the back of the amps if they are moving they are on.

jim

[/quote]


I thought those flaps in the back spinning where fans.  
They work.
I just wanted to make sure I was not overlooking anything.

Thanks for your advise.  I will give it a try.

[DGlass]

I find it very interesting that all the amps go down at the same time especially if the feeds to the amplifiers are 2-way x- overed at the dbx properly. If the amps were all getting the same full range signal at a normal level and you had the system cranked I could see the amps possibly going into protection from being overdriven when hit with a loud scene. But in your case they are band passed for mid-highs and subs.

The amplifiers for the 4733’s fall in on the low side of the recommended amplifier power, on page 7 of the “SRX Series Users Guide” http://www.jblpro.com/pages/mi/mi_pdf/SRX%20Series.pdf  
Even though I would like to see the power available for the 4733's closer to the higher end they are within the recommended power range and would not cause all the amplifiers to go off at the same time.

I do have a couple of questions though:

1)When the audio cuts out are their any fault indicators on the front of the amplifiers?
2)What are the drive levels indicated on the dpra?
3)Explain again what you are doing with the XLR splitter on the High output of the drpa?
4)Are you running in stereo or Mono? Is the dpra running in stereo (2x4 dbx configuration)?
5)If I take what you are saying correctly you jumpering the 4719 to the 4733’s is there a reason you doing this?  If they are x-overed in the dpra and using separate amplifiers? According to the “SRX Series Users Guide” the 4719 subs don’t have a passive mode. They can either be selected for pass thru on Pins +/-1 or +/-2 with the opposite pins feeding the sub cabinet.
6)Are you using a 4-conductor cable to the subs and passing the mid-highs onto the 4733’s?
7)Using the “SRX Series Users Guide” diagrams for Full-Range Two-Way w/sub, on page 13, which way are you wired?
Note: each diagram only represents one side of a stereo configuration and only one sub not a dual.

[Houston]

I find it very interesting that all the amps go down at the same time especially if the feeds to the amplifiers are 2-way x- overed at the dbx properly. If the amps were all getting the same full range signal at a normal level and you had the system cranked I could see the amps possibly going into protection from being overdriven when hit with a loud scene. But in your case they are band passed for mid-highs and subs.

The amplifiers for the 4733’s fall in on the low side of the recommended amplifier power, on page 7 of the “SRX Series Users Guide” http://www.jblpro.com/pages/mi/mi_pdf/SRX%20Series.pdf 
Even though I would like to see the power available for the 4733's closer to the higher end they are within the recommended power range and would not cause all the amplifiers to go off at the same time.

I do have a couple of questions though:

1)When the audio cuts out are their any fault indicators on the front of the amplifiers?  Yes, the fault indicator is lite

2)What are the drive levels indicated on the dpra?

3)Explain again what you are doing with the XLR splitter on the High output of the drpa? I think the "banjo center" connected it this way to bypass the balance barrier block.  I think he was looking for a shortcut.

4)Are you running in stereo or Mono? Is the dpra running in stereo (2x4 dbx configuration)? I am running in stereo mode.  Although the subs are set for mono/bridge

5)If I take what you are saying correctly you jumpering the 4719 to the 4733’s is there a reason you doing this? They set the system up using 4 conductor cable.  The subs are set to pass-thru.

If they are x-overed in the dpra and using separate amplifiers? According to the “SRX Series Users Guide” the 4719 subs don’t have a passive mode. They can either be selected for pass thru on Pins +/-1 or +/-2 with the opposite pins feeding the sub cabinet.
6)Are you using a 4-conductor cable to the subs and passing the mid-highs onto the 4733’s? Yes

7)Using the “SRX Series Users Guide” diagrams for Full-Range Two-Way w/sub, on page 13, which way are you wired? T I believe they are wired Parallel Mode (pin 2)

Note: each diagram only represents one side of a stereo configuration and only one sub not a dual.

[guyofsound]

I find it very interesting that all the amps go down at the same time especially if the feeds to the amplifiers are 2-way x- overed at the dbx properly. If the amps were all getting the same full range signal at a normal level and you had the system cranked I could see the amps possibly going into protection from being overdriven when hit with a loud scene. But in your case they are band passed for mid-highs and subs.

The amplifiers for the 4733’s fall in on the low side of the recommended amplifier power, on page 7 of the “SRX Series Users Guide” http://www.jblpro.com/pages/mi/mi_pdf/SRX%20Series.pdf 
Even though I would like to see the power available for the 4733's closer to the higher end they are within the recommended power range and would not cause all the amplifiers to go off at the same time.

I do have a couple of questions though:

1)When the audio cuts out are their any fault indicators on the front of the amplifiers?  Yes, the fault indicator is lite

2)What are the drive levels indicated on the dpra?

3)Explain again what you are doing with the XLR splitter on the High output of the drpa? I think the "banjo center" connected it this way to bypass the balance barrier block.  I think he was looking for a shortcut.

4)Are you running in stereo or Mono? Is the dpra running in stereo (2x4 dbx configuration)? I am running in stereo mode.  Although the subs are set for mono/bridge

5)If I take what you are saying correctly you jumpering the 4719 to the 4733’s is there a reason you doing this? They set the system up using 4 conductor cable.  The subs are set to pass-thru.

If they are x-overed in the dpra and using separate amplifiers? According to the “SRX Series Users Guide” the 4719 subs don’t have a passive mode. They can either be selected for pass thru on Pins +/-1 or +/-2 with the opposite pins feeding the sub cabinet.
6)Are you using a 4-conductor cable to the subs and passing the mid-highs onto the 4733’s? Yes

7)Using the “SRX Series Users Guide” diagrams for Full-Range Two-Way w/sub, on page 13, which way are you wired? T I believe they are wired Parallel Mode (pin 2)

Note: each diagram only represents one side of a stereo configuration and only one sub not a dual.

I think what you might have is the amps output touching each other. When you plug into the subs they are stock as pin 1 + -. the tops are also 1 + - unless you re-wired the subs they would be the same at low volume somtime you may not have a problem. But at higher vo;umes it would cause a short. open the jack plate on the subs and see if they are set to pin 1 or 2 you would need to have an external panel with jacks for the speakers to use the 4 pin wire correctly.
Do you?
The other thing you should reset the x-over for stereo and wire the tops in stereo, and the subs in stereo you have the output and the eq the only thing you my need is more cable for wiring. No need to split the signal.

jim

[Houston]

[/quote]
I think what you might have is the amps output touching each other. When you plug into the subs they are stock as pin 1 + -. the tops are also 1 + - unless you re-wired the subs they would be the same at low volume somtime you may not have a problem. But at higher vo;umes it would cause a short. open the jack plate on the subs and see if they are set to pin 1 or 2 you would need to have an external panel with jacks for the speakers to use the 4 pin wire correctly.
Do you?
The other thing you should reset the x-over for stereo and wire the tops in stereo, and the subs in stereo you have the output and the eq the only thing you my need is more cable for wiring. No need to split the signal.

jim

[/quote]

The subs are set for pass thru.  On the speaker wire, I have banana plugs for the amps and using speakon for the speaker ends.  The wire is 4 conductor.  It is only at high volume that the amps shut down.

[DGlass]

[I think what you might have is the amps output touching each other. When you plug into the subs they are stock as pin 1 + -. the tops are also 1 + - unless you re-wired the subs they would be the same at low volume somtime you may not have a problem. But at higher vo;umes it would cause a short. open the jack plate on the subs and see if they are set to pin 1 or 2 you would need to have an external panel with jacks for the speakers to use the 4 pin wire correctly.
Do you?
The other thing you should reset the x-over for stereo and wire the tops in stereo, and the subs in stereo you have the output and the eq the only thing you my need is more cable for wiring. No need to split the signal.

jim

[/quote]
This is what I was thinking also but wanted some clarification on a few things. One thing to try is to run the boxes with separate speaker lines back to their respected amplifiers/amplifier channels and see if it all works on the loud passages.

[guyofsound]

[quote=DGlass,May 25 2005, 04:53 PM]
[I think what you might have is the amps output touching each other. When you plug into the subs they are stock as pin 1 + -. the tops are also 1 + - unless you re-wired the subs they would be the same at low volume somtime you may not have a problem. But at higher vo;umes it would cause a short. open the jack plate on the subs and see if they are set to pin 1 or 2 you would need to have an external panel with jacks for the speakers to use the 4 pin wire correctly.
Do you?
The other thing you should reset the x-over for stereo and wire the tops in stereo, and the subs in stereo you have the output and the eq the only thing you my need is more cable for wiring. No need to split the signal.

jim

[/quote]
This is what I was thinking also but wanted some clarification on a few things. One thing to try is to run the boxes with separate speaker lines back to their respected amplifiers/amplifier channels and see if it all works on the loud passages.

[/quote]
Right it doesn't matter if you have banana plugs on one end if you have pins on the subs set to pin 1 along with tops you are going to have the amp outputs touching each other. Not good, can cause problems and void warrantee I would asume, for miswiring.  
Wiring the cabs seperate you have a better chance at figuring out if the amps are touching.

[guyofsound]

[quote=guyofsound,May 26 2005, 10:39 AM]
[quote=DGlass,May 25 2005, 04:53 PM]
[I think what you might have is the amps output touching each other. When you plug into the subs they are stock as pin 1 + -. the tops are also 1 + - unless you re-wired the subs they would be the same at low volume somtime you may not have a problem. But at higher vo;umes it would cause a short. open the jack plate on the subs and see if they are set to pin 1 or 2 you would need to have an external panel with jacks for the speakers to use the 4 pin wire correctly.
Do you?
The other thing you should reset the x-over for stereo and wire the tops in stereo, and the subs in stereo you have the output and the eq the only thing you my need is more cable for wiring. No need to split the signal.

jim

[/quote]
This is what I was thinking also but wanted some clarification on a few things. One thing to try is to run the boxes with separate speaker lines back to their respected amplifiers/amplifier channels and see if it all works on the loud passages.

[/quote]
Right it doesn't matter if you have banana plugs on one end if you have pins on the subs set to pin 1 along with tops you are going to have the amp outputs touching each other. Not good, can cause problems and void warrantee I would asume, for miswiring.  
Wiring the cabs seperate you have a better chance at figuring out if the amps are touching.

[/quote]
Or your speaker ohm load might be to low for the amp because everything is on the same pins

[Schmuck]

just read this and thought of one other thing.  What kind of power drop do you have at the amp rack?  I don't know the current draw of this particular amp, but if you have your whole rack into a 15 amp edison outlet, then could the whole rack not be getting enough power?