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[Richard Stringer]

Hey ya guys, I need a bit of help with setting the limiters on my Dbx Driverack PA, do you think you could help me? I've got two Peavey UL215H mid/highs which are rated at 1,000 watts continuous average power and 2,000 watts program and they're 4 ohms. They're being powered by Yamaha P7000S amplifier, with one cab per channel in stereo. The Yamaha P7000S specs are here :

http://www.yamahaproaudio.com/global...ifications.jsp

Below are the limiter threshold settings i've got for the Driverack PA on the high frequency outputs of the unit based on using the limiter threshold calculator, can you tell me if the threshold value looks accurate?

http://www.poulpetersen.dk/Appn/gblimthc.html

And for the low frequency outputs i've got two JBL SRX728S subs which are rated at 1,600 watts continuous average power and 3,200 watts program, they're 4 ohms. Powering them i've got one JBL MPA750 bridged per sub. Here's the specs for the JBL MPA750 :

http://www.jblproservice.com/pdf/MPA...ies/MPA750.pdf

Below are the settings for the threshold i've got using the same threshold calculator :

http://www.poulpetersen.dk/Appn/gblimthc.html

Does the threshold setting look correct on this one too? I've selected 2 ohms for nominal load of the amplifier because from what I know bridging an amplifier into 4 ohms is using the amplifier as dual 2 ohms right? Or should I select 4 ohms for nominal impedance of the amplifier because i'm bridging at 4 ohms?

Can you guys check these threshold settings are correct and if possible, give me your idea of what you think would be a good setting for the 'Over Easy' setting? Thanks guys, I apreciate your help.

[David Morison]

Richard,
Your Limiter pages just show the default starting values that the website has, not your inputs.
You might be best to take screengrabs of the results of the calculations, save them to a web image host then include those links in your post (or crop them down to less than 800pix wide and attach them directly into the post).
Hope this Helps,
David.

[Richard Stringer]

Ok thanks, I tried but can't manage to capture the web page properly so i've had to type the results manually. Anyway here's the settings :

Loudspeaker -- JBL SRX728S subs
Impedance : 4 Ohms
Max. power : 1,600 Watts
Max. voltage : 80 volts      

Amplifier -- 2 JBL MPA750, one bridged on each SRX728S sub
Input sensitivity : 1vrms   
Output power : 2,000 watts RMS
Nominal load : 4 Ohms (because i'm bridging each MPA750 into 4 ohms on each sub)
Voltage gain : 36.02db      
Limiter Threshold : 4.25dbu

Loudspeaker -- Peavey UL215H mid/highs
Impedance : 4 Ohms
Max. power : 1,000 Watts
Max. voltage : 63.245 volts      

Amplifier -- 1 Yamaha P7000S run in stereo with one Peavey cab per channel
Input sensitivity : Not shown in specifications   
Output power : 1,100 watts RMS per channel
Nominal load : 4 Ohms (because i'm bridging each MPA750 into 4 ohms on each sub)
Voltage gain : 32.1db      
Limiter Threshold : 6.13dbu

Do those limiter settings seem accurate enough?

[Stu McDoniel]

Hey ya guys, I need a bit of help with setting the limiters on my Dbx Driverack PA, do you think you could help me? I've got two Peavey UL215H mid/highs which are rated at 1,000 watts continuous average power and 2,000 watts program and they're 4 ohms. They're being powered by Yamaha P7000S amplifier, with one cab per channel in stereo. The Yamaha P7000S specs are here :

http://www.yamahaproaudio.com/global...ifications.jsp

Below are the limiter threshold settings i've got for the Driverack PA on the high frequency outputs of the unit based on using the limiter threshold calculator, can you tell me if the threshold value looks accurate?

http://www.poulpetersen.dk/Appn/gblimthc.html

And for the low frequency outputs i've got two JBL SRX728S subs which are rated at 1,600 watts continuous average power and 3,200 watts program, they're 4 ohms. Powering them i've got one JBL MPA750 bridged per sub. Here's the specs for the JBL MPA750 :

http://www.jblproservice.com/pdf/MPA...ies/MPA750.pdf

Below are the settings for the threshold i've got using the same threshold calculator :

http://www.poulpetersen.dk/Appn/gblimthc.html

Does the threshold setting look correct on this one too? I've selected 2 ohms for nominal load of the amplifier because from what I know bridging an amplifier into 4 ohms is using the amplifier as dual 2 ohms right? Or should I select 4 ohms for nominal impedance of the amplifier because i'm bridging at 4 ohms?

Can you guys check these threshold settings are correct and if possible, give me your idea of what you think would be a good setting for the 'Over Easy' setting? Thanks guys, I apreciate your help.

Hey Richard...Here is the way you set your limiter/s.  You have got to set your gain structure for your rig.    By setting your gain structure you "get it right" and you get your limiter settings right.

Go to this link below and go to page 8 of the pdf.    There is complete instructions on how
to set your gain structure with your Driverack Pa.   Also, DBX has a pink noise sound file
you can download from them for free and you can use it to set your gain structure if
you do not have a pink noise source.

Here is your link and go to page 8 of the document

I am going to stress you follow the directions completely to get it even close to ball park

http://www.driverack.com/drug/attachments/2.pdf

[Richard Stringer]

Ok thanks Stu, i've had a scan though that, and actually already downloaded that article but not looked at it yet, I forgot about it. I'll read that, thanks again Stu.

[RYAN LOUDMUSIC JENKINS]

Ok thanks, I tried but can't manage to capture the web page properly so i've had to type the results manually. Anyway here's the settings :

Loudspeaker -- JBL SRX728S subs
Impedance : 4 Ohms
Max. power : 1,600 Watts
Max. voltage : 80 volts      

Amplifier -- 2 JBL MPA750, one bridged on each SRX728S sub
Input sensitivity : 1vrms   
Output power : 2,000 watts RMS
Nominal load : 4 Ohms (because i'm bridging each MPA750 into 4 ohms on each sub)
Voltage gain : 36.02db      
Limiter Threshold : 4.25dbu

Loudspeaker -- Peavey UL215H mid/highs
Impedance : 4 Ohms
Max. power : 1,000 Watts
Max. voltage : 63.245 volts      

Amplifier -- 1 Yamaha P7000S run in stereo with one Peavey cab per channel
Input sensitivity : Not shown in specifications   
Output power : 1,100 watts RMS per channel
Nominal load : 4 Ohms (because i'm bridging each MPA750 into 4 ohms on each sub)
Voltage gain : 32.1db      
Limiter Threshold : 6.13dbu

Do those limiter settings seem accurate enough?

Looks pretty close but you are a little off on the subs.

Also, the DRPA limiters are only accurate to 1 dBu.  So for your Yamaha P7000s for the tops you would be at 6dBu (approx 950 Watts per box). 

When you bridge an amp you get an additional 6dBu of gain.  Here is where you are off on the subs.  You really have about 41dBu of gain on the JBL amps when bridged into 4 ohms (1900 Watts).  You limiter would be -1dBu.

[Richard Stringer]

Thanks Ryan, that helps me, people have told me that the built in clip limiters in the Yamaha and JBL  amplifiers would be better than the Driverack PA's, do you think that might be true? If so, i'll leavge off the clip limiters on the Driverack.

[Mark Long]

Thanks Ryan, that helps me, people have told me that the built in clip limiters in the Yamaha and JBL  amplifiers would be better than the Driverack PA's, do you think that might be true? If so, i'll leavge off the clip limiters on the Driverack.

IIRC, the DRPA doesn't have true "brick wall" limiters and the guys over at the Dbx forums usually don't recommend using them until you get into the DR260 or above. 

[Bill Hornibrook]

There is no limiting on a P7000s. This has been brought up in other forums and I verified it on my own P7000s. The front panel does not lie. Those red lights are labeled "Clip", and when they start flashing red that's exactly what that amp does.

Here's a real world way to set your limiters on the DRPA with that setup. The continuous rating for that amp and those speakers are about the same. Set OverEasy to around 5 so the signal is not just slamming against the limiters, run a something through the system that approximates the loudest you're going to be that night, and when the "Clip" lights on the P7000s start to flicker, back of threshold on that channel of the DRPA until they stop.

[Richard Stringer]

Thanks guys, and thanks Bill, that's what i'm gonna do, i'll see how that goes, I never the system anyway, not even flickering the clip lights.

[Greg_Cameron]

My only argument against using an 'over easy' setting for the limiter is that you can actually reduce dynamic range somewhat since you're compressing the signal somewhat and possibly shaving off a few dB of output. A few dB equates to half the output power of the amp. If that ok, fair enough. But you might not be getting everything you can out of the system with that type of setup, especially if you're using an amp that matching only the rms rating of the boxes rather than the program rating.

And yes, the dbx limiters don't sound very good. You have to step up to relatively expensive processors to get "good" sounding limiters.

Greg

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