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Using Line Outs On Crown Amps


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#1 RogerB

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Posted 21 May 2012 - 10:51 AM

Hello,

What, if any, degradation in signal strength occurs in using the line outs on a Crown amp as a pass through to more amps?

I'm thinking of using one Crown amp connected to the Main Out L and R of a Mackie Mixer (1604 VLZ) for 2 x 15" JBL's for FOH.  I would then connect another Crown amp via the 1st amps line outs to power 2 more 15" JBL's for FOH.  To that amp I'd connect a third Crown amp via the 2nd amps line outs to power 2 x 18" JBL subs.

FYI, I'd power 4 X 12" JBL monitors with a fourth Crown amp connected to the Aux 1 and 2 of the Mackie Mixer.

Please critique my methods/thoughts and give me any other suggestions you might provide.

Regards,

RogerB

#2 dakos

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Posted 22 May 2012 - 04:03 AM

QUOTE(RogerB @ May 21 2012, 10:51 AM) View Post
Hello,

What, if any, degradation in signal strength occurs in using the line outs on a Crown amp as a pass through to more amps?

I'm thinking of using one Crown amp connected to the Main Out L and R of a Mackie Mixer (1604 VLZ) for 2 x 15" JBL's for FOH.  I would then connect another Crown amp via the 1st amps line outs to power 2 more 15" JBL's for FOH.  To that amp I'd connect a third Crown amp via the 2nd amps line outs to power 2 x 18" JBL subs.

FYI, I'd power 4 X 12" JBL monitors with a fourth Crown amp connected to the Aux 1 and 2 of the Mackie Mixer.

Please critique my methods/thoughts and give me any other suggestions you might provide.

Regards,

RogerB

Dear Roger,
The Line Outs on the back of the amp are connected in parallel to the inputs, no processing or conversion of any kind is done to the signal on that stage so it's safe to daisy chain amps like that.

A few pointers:
  • Make sure the cables are not too long - You really have to over do it here, anything under 100ft is fine, even longer is fine.
  • Use balanced twisted cables - Ground can be lifted on one end of the cable, not on both ends. If you need Phantom Power then both grounds need to be connected, in this case pay attention to the next pointer.
  • You need to try and connect all your gear to wall sockets that are grounded the same way otherwise you might need to "lift the ground" to eliminate ground loop hum (not possible when using phantom power).
  • Make sure they are not running in the vicinity of the power cords or where disturbances might be picked up.
Now for the configuration:
  • The 4 X monitors are fine from the aux, they should get a full range signal.
  • I don't know which amps you are using (with the exception of one IT4000) on which speaker model, I didn't see any crossover in the gear list and you need one for FOH or use the internal amps DSP or built in crossover but you need one in every amp except for the monitors amp.
  • One more thing, I see you use 4 X 15" JBLs for FOH, it's not recommended for getting higher SPL due to comb filtering, only for wider coverage.
If you need more clarifications please ask.

#3 RogerB

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Posted 22 May 2012 - 10:32 AM

QUOTE(dakos @ May 22 2012, 04:03 AM) View Post
QUOTE(RogerB @ May 21 2012, 10:51 AM) View Post
Hello,

What, if any, degradation in signal strength occurs in using the line outs on a Crown amp as a pass through to more amps?

I'm thinking of using one Crown amp connected to the Main Out L and R of a Mackie Mixer (1604 VLZ) for 2 x 15" JBL's for FOH.  I would then connect another Crown amp via the 1st amps line outs to power 2 more 15" JBL's for FOH.  To that amp I'd connect a third Crown amp via the 2nd amps line outs to power 2 x 18" JBL subs.

FYI, I'd power 4 X 12" JBL monitors with a fourth Crown amp connected to the Aux 1 and 2 of the Mackie Mixer.

Please critique my methods/thoughts and give me any other suggestions you might provide.

Regards,

RogerB

Dear Roger,
The Line Outs on the back of the amp are connected in parallel to the inputs, no processing or conversion of any kind is done to the signal on that stage so it's safe to daisy chain amps like that.

A few pointers:
  • Make sure the cables are not too long - You really have to ever do it here, anything under 100ft is fine, even longer is fine.
  • Use balanced twisted cables - Ground can be lifted on one end of the cable, not on both ends. If you need Phantom Power then both grounds need to be connected, in this case pay attention to the next pointer.
  • You need to try and connect all your gear to wall sockets that are grounded the same way otherwise you will need to "lift the ground" to eliminate ground loop hum (not possible when using phantom power).
  • Make sure they are not running in the vicinity of the power cords or where disturbances might be picked up.
Now for the configuration:
  • The 4 X monitors are fine from the aux, they should get a full range signal.
  • I don't know which amps you are using (with the exception of one IT4000) on which speaker model, I didn't see any crossover in the gear list and you need one for FOH or use the internal amps DSP or built in crossover but you need one in every amp except for the monitors amp.
  • One more thing, I see you use 4 X 15" JBLs for FOH, it's not recommended for getting higher SPL due to comb filtering, only for wider coverage.
If you need more clarifications please ask.


Hello Dakos,

As usual you are very informative.......Thank You!

About your pointers:  The units will be plugged in to a Furman 20 amp power conditioner.  The cables will be less than 50 ft.  I'll ensure the use of balanced twisted cables.

About your comments on the equipment:  We'll use a combo of internal DSP on those that have it and Driveracks on the others.  We normally use only 2 JBL's for FOH but have used the other 2 when in an outside environment.

Thanks, again, for all your help!

Regards,

RogerB




#4 dakos

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Posted 22 May 2012 - 01:55 PM

QUOTE(RogerB @ May 22 2012, 10:32 AM) View Post
Hello Dakos,

As usual you are very informative.......Thank You!

About your pointers:  The units will be plugged in to a Furman 20 amp power conditioner.  The cables will be less than 50 ft.  I'll ensure the use of balanced twisted cables.

About your comments on the equipment:  We'll use a combo of internal DSP on those that have it and Driveracks on the others.  We normally use only 2 JBL's for FOH but have used the other 2 when in an outside environment.

Thanks, again, for all your help!

Regards,

RogerB

This is a good link that illustrates how speaker placement affects the sound. It doesn't cover one of the most recommended speaker placement which is placing one speaker on top of the other when the top speaker is up side down to make the HF drivers as close as possible which is what I suggest you do.
http://homepage.mac.com/randyhyde/webster....audioStuff.html

The other option is a bit more complex, bi amp the two speaker sets and subs of the FOH, lets say 100Hz and below goes to the 18 inchers that are on the floor, 105Hz and all the way up goes to one set of JBLs, the other set of JBLs would get 105Hz to 400Hz. This combined configuration would give you quasi three way configuration. The speakers have to be placed with a distance of less then 1/4 wave length of the higher frequency fed to the driver (400Hz here so less then 8.5") and mounted up on speaker stands to get rid of boundary cancellation from the floor and walls. This configuration needs three separate amps and one dedicated DRPA.

#5 RogerB

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Posted 22 May 2012 - 02:17 PM

QUOTE(dakos @ May 22 2012, 01:55 PM) View Post
QUOTE(RogerB @ May 22 2012, 10:32 AM) View Post
Hello Dakos,

As usual you are very informative.......Thank You!

About your pointers:  The units will be plugged in to a Furman 20 amp power conditioner.  The cables will be less than 50 ft.  I'll ensure the use of balanced twisted cables.

About your comments on the equipment:  We'll use a combo of internal DSP on those that have it and Driveracks on the others.  We normally use only 2 JBL's for FOH but have used the other 2 when in an outside environment.

Thanks, again, for all your help!

Regards,

RogerB

This is a good link that illustrates how speaker placement affects the sound. It doesn't cover one of the most recommended speaker placement which is placing one speaker on top of the other when the top speaker is up side down to make the HF drivers as close as possible which is what I suggest you do.
http://homepage.mac.com/randyhyde/webster....audioStuff.html

The other option is to bi amp the two speaker sets and subs of the FOH, lets say 100Hz and below goes to the 18 inchers that are on the floor, 105Hz and all the way up goes to one set of JBLs, the other set of JBLs would get 105Hz to 400Hz. This combined configuration would give you quasi three way configuration. The speakers have to be placed with a distance of less then 1/4 wave length of the higher frequency fed to the driver (400Hz here so less then 8.5") and mounted up on speaker stands to get rid of boundary cancellation from the floor and walls. This configuration needs three separate amps and one dedicated DRPA.


Dakos,

Very good info, thanks!!

Regards,

RogerB