Best Tuning for JBL Sound Power Subs

desiBel

Hi guys,

I would like to ask some general questions, but also some specific questions as to my setup. I am on a quest to find the optimum tunings for my setup and would appreciate any help and advice.

My equipment list is:

x1 Soundcraft Si Expression 3 (digital console)
x1 DriveRack PX
x2 JBL PRX 515 (Active stereo mains): http://www.jblpro.com/ProductAttachment ... 515.v6.pdf
x2 JBL Dual 18" Sound Power SP 128S (Passive), archived vintage on JBL website: http://www.jblpro.com/pub/obsolete/Soun ... sp128s.pdf
Here is the recommended tunings using a DSC 280 (JBL processor) for the JBL Sound Power SP128S subs: http://www.jblpro.com/ProductAttachments/spwr.pdf

and x1 Crown I-Tech 5000 HD to power the dual 18" subs, two channels 'y linked' and 4 ohm operation:
http://www.crownaudio.com/en/products/i-tech-5000hd

Am I overpowering my Subs?

My setup is configured as follows:

I place one JBL PRX515 main on top of one dual 18" sub per side, like a stack. (Sometimes I centre the subs according to the stage and lay them down on the floor together so there is essentially 4 subs in a row and place the tops on stands either side of the stage on tripods).

The main L/R outputs from mixer to DRPX L/R inputs, which is setup for stereo mains and mono sub.
The L/R outputs on the DRPX to the L/R JBL PRX 515's, left output to the left JBL PRX515 main and right output from the DRPX to the right side JBL PRX main from FOH perspective.

Then the Left sub output from the DRPX is sent to channel one input of the Crown itech 5000 HD amp which is internally 'y linked' so a speakon cable from channel one goes to one side dual sub and speakon cable from channel 2 goes to the other side dual sub.

The DriveRack PX is set up for the JBL PRX 515 mains as these are listed in the DriveRack preset. The two dual subs are selected as custom subs and running out of the DriveRack as Mono. Should I be running four subs in two enclosures Mono?

The crossover settings are subs high pass at 28Hz LR24, to low pass 116Hz LR24 and Mains high pass at 65Hz LR24 to OUT. With regards to the subs specs, is this ok?

I wanted to know if I'm doing things right and how to use the JBL tunings provided for the Sound Power Subs with the DriveRack for a tighter and controlled, tuned sound. I can achieve speaker delay from my Crown power amp that are running the subs, barring digital latency, should I delay these using the power amp by 0.042ms, as on the tuning sheet and should I be using input delay or speaker delay on this? Also, how do I use the tuning sheet to set the PEQ's in the DriveRack for the subs? Would these tunings pertain to the DriveRack. I'm actually not sure what tunings from the sheet to take?

Also, my general question was should I use a high pass filter at 30Hz that I have on my mixer on the master bus to protect the subs from over-excursion? Or would this affect the Phase linearity of the upper frequencies like I have read somewhere?

I hope I have included everything you require?

Thank you.


Ps. I have just purchased the new JBL SRX815p (active), these have their own DSP, got to figure out some new configurations with the DriveRack if I want to use these as well as the PRX's so 4 tops (Mains) now...

Dra

desiBel wrote:

Hi guys,

I would like to ask some general questions, but also some specific questions as to my setup. I am on a quest to find the optimum tunings for my setup and would appreciate any help and advice.

My equipment list is:

x1 Soundcraft Si Expression 3 (digital console)
x1 DriveRack PX
x2 JBL PRX 515 (Active stereo mains): http://www.jblpro.com/ProductAttachment ... 515.v6.pdf
x2 JBL Dual 18" Sound Power SP 128S (Passive), archived vintage on JBL website: http://www.jblpro.com/pub/obsolete/Soun ... sp128s.pdf
Here is the recommended tunings using a DSC 280 (JBL processor) for the JBL Sound Power SP128S subs: http://www.jblpro.com/ProductAttachments/spwr.pdf

and x1 Crown I-Tech 5000 HD to power the dual 18" subs, two channels 'y linked' and 4 ohm operation:
http://www.crownaudio.com/en/products/i-tech-5000hd

Am I overpowering my Subs? You should be fine if you raise the HPF to 40hz BW18.

My setup is configured as follows:

I place one JBL PRX515 main on top of one dual 18" sub per side, like a stack. (Sometimes I centre the subs according to the stage and lay them down on the floor together so there is essentially 4 subs in a row and place the tops on stands either side of the stage on tripods).

The main L/R outputs from mixer to DRPX L/R inputs, which is setup for stereo mains and mono sub.
The L/R outputs on the DRPX to the L/R JBL PRX 515's, left output to the left JBL PRX515 main and right output from the DRPX to the right side JBL PRX main from FOH perspective.

Then the Left sub output from the DRPX is sent to channel one input of the Crown itech 5000 HD amp which is internally 'y linked' so a speakon cable from channel one goes to one side dual sub and speakon cable from channel 2 goes to the other side dual sub.

The DriveRack PX is set up for the JBL PRX 515 mains as these are listed in the DriveRack preset. The two dual subs are selected as custom subs and running out of the DriveRack as Mono. Should I be running four subs in two enclosures Mono? It really doesn't matter.

The crossover settings are subs high pass at 28Hz LR24, to low pass 116Hz LR24 and Mains high pass at 65Hz LR24 to OUT. With regards to the subs specs, is this ok? Subs - 40hz BW18 - 100hz LR24, Mains - 100hz LR24 - out.

I wanted to know if I'm doing things right and how to use the JBL tunings provided for the Sound Power Subs with the DriveRack for a tighter and controlled, tuned sound. I can achieve speaker delay from my Crown power amp that are running the subs, barring digital latency, should I delay these using the power amp by 0.042ms, as on the tuning sheet and should I be using input delay or speaker delay on this? That delay is for if you were bi-amping main speakers that you don't have.Also, how do I use the tuning sheet to set the PEQ's in the DriveRack for the subs? Would these tunings pertain to the DriveRack. I'm actually not sure what tunings from the sheet to take? The only spec that applies is the 51hz @ .75 with 1.5 boost. .75 bandwidth = 1.9 Q. So, 51hz, Q=1.9, +1.5db. Make sure that the PEQ type is Bell. All the other stuff is for SP main speakers.

Also, my general question was should I use a high pass filter at 30Hz that I have on my mixer on the master bus to protect the subs from over-excursion? Or would this affect the Phase linearity of the upper frequencies like I have read somewhere?

I hope I have included everything you require?

Thank you.


Ps. I have just purchased the new JBL SRX815p (active), these have their own DSP, got to figure out some new configurations with the DriveRack if I want to use these as well as the PRX's so 4 tops (Mains) now...

Dra

desiBel

Thank you Dra.

I'm going to use this config on Saturday in a live situation.

You guys are wonderful!

desiBel

…Just to double check with the PEQ's would I not also use the A2 frequency listed in the tunings as well as what you have stated with the A1 frequency? Also these tunings are originally for a DSC 280 (JBL management Processor).

This A2 frequency is 277hz, 12 Hi-shelf, boost 3?

http://www.jblpro.com/ProductAttachments/spwr.pdf

Just to be sure?

Dra

That is a high shelf with a slop of 12db/oct and a 3db boost. That is confusing since 277hz is more than an octave above the x-over. You can add it if you wish, but it won't affect any thing. The sound power's are an install speaker. It could be that they sometimes are ran full range. I wouldn't.

DRA

desiBel

Thank you for clearing that up for me DRA, very much appreciated