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[Tim Sheumack]

Hi guys

Thanks in advance for your expertise and advice.

I’ve got an upcoming outdoor jazz show (that I’ve done for a number of years) coming up and would love some advice on the best way to run my system.

Amps available:

QSC PLX3402 (700w per channel @ 8 ohms)
QSC RMX2450 (500w per channel @ 8 ohms)
QSC RMX1450 (280w per channel @ 8 ohms)
Crest Audio CA9 (600w per channel @ 8 ohms)
2 x Quest 2004 (490w per channel @ 8 ohms)


Speakers:
2 x EV Eliminator Dual 18” Passive Subs 1000watt/4 ohms
4 x Acoustic Technologies FR01 v2 800watt program/8 ohms

*Also running DBX 2/3 way stereo crossover

My questions were basically:
2 x Subs:
Should I run the 2 subs bridged mono...in this instance do I daisy chain them to each other and do I need a specially wired cable to run them in bridges mono (still trying to get my head around this)

4x At FR01 v2 Full range boxes:

I was going to run a pair each side but should I run each pair off a single amp channel each or daisy chain the pair off a single amp channel (and they would become 2 x 4ohms)

* I also run a 3rd pair of AT FR01s as a delay system

Also I don’t necessarily need to run the system in stereo.

Basically how would you do it based on the above gear?

Anyway thanks for the advice...I’ve done this show (open air jazz fest) successfully for a number of years using my Beyma dual concentric 15” top boxes, which are great but they are huge heavy monsters and now I wish to use the 2-a-side AT FR01s instead as they are lovely sounding boxes and don’t hammer my back (I do this gig by myself).


Thanks muchly !

[Mike Pyle]

Hi guys

Thanks in advance for your expertise and advice.

I’ve got an upcoming outdoor jazz show (that I’ve done for a number of years) coming up and would love some advice on the best way to run my system.

Amps available:

QSC PLX3402 (700w per channel @ 8 ohms)
QSC RMX2450 (500w per channel @ 8 ohms)
QSC RMX1450 (280w per channel @ 8 ohms)
Crest Audio CA9 (600w per channel @ 8 ohms)
2 x Quest 2004 (490w per channel @ 8 ohms)


Speakers:
2 x EV Eliminator Dual 18” Passive Subs 1000watt/4 ohms
4 x Acoustic Technologies FR01 v2 800watt program/8 ohms

*Also running DBX 2/3 way stereo crossover

My questions were basically:
2 x Subs:
Should I run the 2 subs bridged mono...in this instance do I daisy chain them to each other and do I need a specially wired cable to run them in bridges mono (still trying to get my head around this)

4x At FR01 v2 Full range boxes:

I was going to run a pair each side but should I run each pair off a single amp channel each or daisy chain the pair off a single amp channel (and they would become 2 x 4ohms)

* I also run a 3rd pair of AT FR01s as a delay system

Also I don’t necessarily need to run the system in stereo.

Basically how would you do it based on the above gear?

Anyway thanks for the advice...I’ve done this show (open air jazz fest) successfully for a number of years using my Beyma dual concentric 15” top boxes, which are great but they are huge heavy monsters and now I wish to use the 2-a-side AT FR01s instead as they are lovely sounding boxes and don’t hammer my back (I do this gig by myself).


Thanks muchly !

Run the subs on the PLX3402 in stereo. Do not daisy chain them, as that would reduce the impedance to a nominal 2 ohms.

The Quest has a little higher spec at 4 ohms than the RMX2450, so I would use that in stereo to drive the tops - 2 a side as you said and paralleled. I'm assuming that you have the 50 degree pattern horns and not 100 degree? If you have the 100 degree horns just run 1 cab per side.

If you are going to run delays as you mention then you will need a processor capable of delaying the signal to that amp by the appropriate amount.

[Paul G. OBrien]

My questions were basically:
2 x Subs:
Should I run the 2 subs bridged mono...in this instance do I daisy chain them to each other and do I need a specially wired cable to run them in bridges mono (still trying to get my head around this)

4x At FR01 v2 Full range boxes:

I'd suggest you bridge the RMX2450 and the CA9 into the subs and use the pair of Quest amps to power the tops connected 1 box per channel, that gives you a balanced system power wise and you can co-locate an amp rack behind each speaker stack for short speaker cable runs. Some may question the power levels available but Jazz is generally quite dynamic so additional peak power will come in handy.
Connecting the subs to the amps in bridged mode usually requires a special speakon cable with the amp end wired to pins 1+2+, be sure to check the corresponding user manuals for model specific settings.. there are usually switches that need to be set and control and input connection requirements that must be observed.

[Mike Pyle]

I'd suggest you bridge the RMX2450 and the CA9 into the subs and use the pair of Quest amps to power the tops connected 1 box per channel, that gives you a balanced system power wise. Some may question the power levels available but Jazz is generally quite dynamic so additional peak power will come in handy.
Connecting the subs to the amps in bridged mode usually requires a special speakon cable with the amp end wired to pins 1+2+, be sure to check the corresponding user manuals for model specific settings.. there are usually switches that need to be set and control and input connection requirements that must be observed.

I would agree with using the Quest amps 1 box per channel. Didn't notice that there were two of these amps available. The RMX2450 has a history of thermaling when running 4 ohm loads bridged.

[Stephen Kirby]

The EV Eliminators typically used the older EVM18B speakers.  Which definitely would not handle 1000W.  The raw driver rating is 400W.  Don't know about the cabinet tuning and where it would unload.

[Chris Grimshaw]

The EV Eliminators typically used the older EVM18B speakers.  Which definitely would not handle 1000W.  The raw driver rating is 400W.  Don't know about the cabinet tuning and where it would unload.

2 per cab, though, so that's 800w.

I'd use the RMS2450 for the subs, one cab per side so it's running at 4ohm, and the PLX3402 for tops. My reasoning is this: one of the bands (either bass or mid-high) is gonna be a little short on headroom, since you've got a big amp and a few smaller ones. I'd much rather have a sub amp clipping than the mid-highs. Clipping the sub amp is unlikely to be audible to the audience, but if the mid-high amp clips, it'll be much more obvious.

I'd also upgrade to a digital crossover asap, so you can apply delays, EQs, and put in a protective highpass for the subs.

Chris

[Tim Sheumack]

2 per cab, though, so that's 800w.

I'd use the RMS2450 for the subs, one cab per side so it's running at 4ohm, and the PLX3402 for tops. My reasoning is this: one of the bands (either bass or mid-high) is gonna be a little short on headroom, since you've got a big amp and a few smaller ones. I'd much rather have a sub amp clipping than the mid-highs. Clipping the sub amp is unlikely to be audible to the audience, but if the mid-high amp clips, it'll be much more obvious.

I'd also upgrade to a digital crossover asap, so you can apply delays, EQs, and put in a protective highpass for the subs.

Chris

Thanks for everyone’s input and all makes great sense ! I’m having a dry run in the backyard today so I’ll hook and try some of the different suggested formats.

Chris...using the PLX3402 for my 2 full range boxes per side FOH are you saying to run to say the first left side box and then daisy chain (via short Speakon) into the box beside it breaking the boxes down to 4 ohm each and likewise for the right side FOH from amp channel 2? Is my understanding correct?

Xover wise I do also have a DBX digital processor but it has on 2 occasions had a screen blank mid show and needed a restart so gone back to my trusty 234XL analogue unit. Delay wise I use the Behringer DEQ2496 Ultracurve for offset, which seems to do a fine job (occasional tune the delay stacks with the EQ on this unit if needed but usually just use it for delay).

Thanks
Tim

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