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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => SR Forum Archives => LAB Lounge FUD Forum Archive => Topic started by: Rusty Irby on June 13, 2008, 07:52:49 AM

Title: To use or not to use??????
Post by: Rusty Irby on June 13, 2008, 07:52:49 AM
After seeing some photos of racks and reading, I find that alot of people dont use a 31 band eq on sub duty. I find that I really dont need one myself. If this was the case I could run stereo on my mains, and aux feed my subs. Any recommendations?
Title: Re: To use or not to use??????
Post by: Tom Young on June 13, 2008, 08:56:32 AM
A 1/3-octave graphic EQ is no where near as effective as a few bands of parametric equalization can be with subwoofers. I almost always find 2-3 peaks that need a little energy taken out.

Given that you will need a high-pass filter, a low-pass (crossover) filter, delay, limiting, gain adjustment......when you add in the need for parametric filters it is almost certainly the case where DSP is the best choice.

HTH
Title: Re: To use or not to use??????
Post by: Duncan McLennan on June 13, 2008, 09:31:50 AM
Sounds like a plan to me.  If you're running a digital board, you can usually use parametric filters on the AUX output, assuming you want to change something after the processor is setup.
Title: Re: To use or not to use??????
Post by: Rusty Irby on June 13, 2008, 05:50:59 PM
OK, eventually I will have a DSP, hopefully within a month. But without a DSP an EQ on subs is pretty much useless?
Title: Re: To use or not to use??????
Post by: Duncan McLennan on June 13, 2008, 06:14:30 PM
If you have no DSP or parametric EQs on the board, I would take an EQ, assuming you have one.  I certainly wouldn't buy one specifically for that purpose.  

Without a DSP at all I would certainly want the EQ to 'high pass filter' the subs, sort of, just by notching out everything too low.
Title: Re: To use or not to use??????
Post by: Tom Young on June 13, 2008, 07:24:09 PM
"OK, eventually I will have a DSP, hopefully within a month. But without a DSP an EQ on subs is pretty much useless?"

Yes. Your chances that the peaks in the subwoofer response fall on 31Hz, 40Hz, 50Hz, 63Hz, 80Hz or 100Hz are pretty slim. Plus they are not likely to be 1/3-octave in width.

"If you have no DSP or parametric EQs on the board, I would take an EQ, assuming you have one. I certainly wouldn't buy one specifically for that purpose."

I wouldn't buy (just) an EQ either, other than a bargain (on a well designed one) on Ebay. I would, however, consider a DSP "loudspeaker management system" well worth the investment.

"Without a DSP at all I would certainly want the EQ to 'high pass filter' the subs, sort of, just by notching out everything too low."

This may be better than nothing but it doesnt even begin to approach what a real HPF accomplishes.

Depending on how you push the system, a properly set HPF can mean the difference between your subs surviving or not.
Title: Re: To use or not to use??????
Post by: Rusty Irby on June 13, 2008, 08:29:26 PM
Yes, it is an extra EQ channel that I have.  The only parametric I have is on the MixWiz. I have seriously been debating the DSP. Since I am a weekend warrior, Im trying to justify the cost of a dbx 260 or better VS. the Behringer DCX2496?? With the DBX260 it already has the speaker parameters for my mains, but I dont think it has those for my LS808's. I did find a DBX 260 on the internet yestersday for $700 new, free shipping in U.S.
Title: Re: To use or not to use??????
Post by: Tim Padrick on June 13, 2008, 09:08:12 PM
The EQ on the MixWiz is semi-parametric, as it does not have bandwidth adjustment.

Something like a Rane PE15 would work nicely, and could be used as a channel or group EQ down the road.  (Something tells me that a PE15 will show up on eBay soon Rolling Eyes)
Title: Re: To use or not to use??????
Post by: Nick Enright on June 18, 2008, 10:23:35 AM
Definately go with a DSP, they give you so much more control over what your system is doing that a simple regular crossover pales by comparison.

I would'nt use aux fed subs at this point either. If you've got enough gas (amp power) just run a normal stereo two way system, considering your inexperience you will be better able to concentrate on mixing, and using the tools you do have (channel eq, compressors, etc...) than running an aux sub.

Peavy CEX5's are pretty good to start with also... They are 2x4 DSP units, I got one for 56.00 shipped off e-bay. Pheonix connectors and XLR Jacks can be had from Mouser.

If you need a manual for a CEX5 I've got a rough draft from a Peavy tech I called when I bought my two... They dont have tons of delay time, but do have a 5 band parametric on each input and a 3 band on each output, the limiters are easy to set too.

nick
Title: Re: To use or not to use??????
Post by: John Chiara on June 19, 2008, 03:28:19 PM
Parametric for me.
John
Title: Re: To use or not to use??????
Post by: Tim McCulloch on June 19, 2008, 07:14:47 PM
Hi Nick-

Ditto on the CEX5.  I found one on eBay a few years back and it became my 'swiss army processor' in a personal gig rack.  It's been a DA, delay, EQ, compressor & limiter... and a crossover a couple of times.

Big and heavy by today's standards but affordable... makes it perfect for Rusty and others to get their feet wet in the system DSP world.

Have fun, good luck.

Tim Mc
Title: Re: To use or not to use??????
Post by: Nick Enright on June 23, 2008, 11:48:34 PM
Tim-

Yeah, I found a couple PC4's and have used them for years, as my system grew last year, I decided to just go with DSP over regular analog. The big systems I run are 4-way, and need time alignment. I would love a Protea, or anyother modern 4x8, but for my $300 the two CEX5's plus a rack, two 1space panels, jacks and nice pheonix connectors was well worth it.

nick