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Need EQ for center channel.


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5 replies to this topic

#1 of 6 OFFLINE   John F. Palacio

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Posted May 29 2006 - 03:45 AM

I needed to move my center channel PSB Stratus 6c from top of the RP set to the bottom when I changed form a CRT based to a DLP due to depth issues.

I had a very clear and intelligible center channel and now I don't. I need a single channel EQ for just the center channel. I want to roll off anything below 120-150 Hz and boost the 2500-5000 Hz range. Nothing fancy.

There's a whole bunch of multichannel EQ's out there and a host of pricey pro-grade single channel ones.

I am looking to get an unbalanced, moderately priced EQ that will do the job cleanly.

Any ideas?
Best regards.

John
Freelance Video Control Engineer

#2 of 6 OFFLINE   David-Wright

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Posted May 29 2006 - 09:16 AM

I hope you get some replies because I am thinkng of adding an EQ to my center channel as well. Getting clear dialog seems to be the holy grail of home theater. The dialog mix in the soundtrack may make it challenging to begin with.

My question is whether most EQs are made for signal level or can they handle line level as well?
David-Wright

#3 of 6 OFFLINE   Wayne A. Pflughaupt

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Posted May 29 2006 - 09:39 AM

John,

I’m surprised your receiver’s tone controls can’t do what you need. Most of them these days offer a variety of center frequencies to choose from.
Quote:
I need a single channel EQ for just the center channel. I want to roll off anything below 120-150 Hz and boost the 2500-5000 Hz range. Nothing fancy.
Sounds like a 2/3-octave (15-band) EQ is all you need, but all of those are two-channel. Not that it would hurt anything to leave one channel vacant...

Quote:
There's a whole bunch of multichannel EQ's out there and a host of pricey pro-grade single channel ones. I am looking to get an unbalanced, moderately priced EQ that will do the job cleanly.
There are plenty of cheapie pro equalizers, but you don’t want any of them. You’re probably going to find that “moderately priced” and “clean” are hard to come by in the same package. You’re talking about your center channel here, which is arguably the most important in a home theater. You don’t want one that colors the sound (except for where you apply equalization), adds distortion or noise. This pretty much rules out any budget EQs from brands like Pyle, DOD, Nady and the like. Probably Behringer, too, although some people report being happy with them.

Especially pay attention to the S/N ratios or noise floors with any EQ you get. It needs to be well below your receiver’s specs. Otherwise, you won’t be able to do any boosting, because it’ll probably add audible noise.

It can be hard to tell if an equalizer is adding coloration with program material, but you can usually tell by playing a pink noise source through it. Make sure the “Engaged” and “Bypass” modes are level matched, and all sliders set to flat. If you hear a tonal change in the pink noise signal when you engage the EQ, it’s coloring the signal. Finding a pro EQ that’ll pass this test may ultimately be a hopeless pursuit, however: even my $1500 TDM Design equalizer flunked.

If you’re tight for money, I suggest eBaying a used model from a respectable brand. Look on for one that was in a permanent installation or a studio, if possible, as those will be in the best condition. That’s primarily for cosmetics, though – even one that was used on the road will probably work just fine, because these EQs are ruggedly built (which is one reason why new prices for good ones aren’t cheap).

As far as brands to look for, the older Ashly models with a black face can be had pretty cheap – the GQ graphics and PQ parametrics. A mono GQ recently sold on eBay for mere $90.

Other brands, Symetrix used to make a dandy three-channel half-rack parametric. Haven’t used it, but the brand is respectable, and for usually under $75 it’s worth a shot.

dbx’s mid-line and up EQs are probably worth a look.

One brand you might seriously look into is White Instruments, a high-end brand that gets no respect in the resale market, even though new prices for their gear is pretty high. Most of White’s EQs are unique in that they use rotary knobs instead of sliders, which is probably why most pro users don’t like them - you don’t get that “visual” of your settings. However, for a set-it-and-leave-it situation like yours, that won’t matter at all. The only downside is that they look pretty funky with all the knobs, but if you want high-end quality on the cheap, I’d give White a serious consideration.

All of these brands I’m merely recommending based on their reputation. I haven’t used any of them in a home system, so I can’t tell you if they pass the pink noise test. You’ll also need to look up their specs from the manufacturer’s websites.

A real coup would be if you could score a discontinued AudioControl C-131 1/3-octave EQ on eBay. It listed for $500 and had specs that bested pro equalizers costing twice as much.

Of course, you do know your receiver will need pre-out and main-in connections, or an outboard amp, right?

Regards,
Wayne A. Pflughaupt

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#4 of 6 OFFLINE   Alan M

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Posted May 30 2006 - 12:59 AM

I have a 10 band,2 channel EQ hooked up between my pre/pro and my amp strickly for my center channel.The tone controls on the pre/pro would have effected all 5 speakers,which I did not want to do.

In this config,I'm only using 1 channel of the EQ,which after being adjusted was calibrated with the rat shack meter.
I must say,this setup works very well and gives me crystal clear dialogue.

#5 of 6 OFFLINE   John F. Palacio

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Posted May 30 2006 - 04:34 AM

Thank you, Wayne. Lots of good information you have provided. As why my preamps tone controls are not enough.
1- They affect all channels and therefore would EQ all 5 speakers.
2- I am using a Sunfire TGIII processor with a Sunfire Signature 5 channel amp (Mains and rears) and a Carver A-760 stereo amp for the twin SVS subs. The TGII only has shelving bass and treble controls.
Maybe this would help but only if applied to the center channel.

Alan.

What brand and model are you using?
Best regards.

John
Freelance Video Control Engineer

#6 of 6 OFFLINE   Alan M

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Posted May 30 2006 - 07:07 AM

Its a very old EQ that I had laying around the house.It must be at least 20 years old,made by Audiosource.The model is the EQ 8,series 2.

As Wayne has mentioned,running pink noise with the bypass button engaged and disengaged will tell you whether your coloring the sound and if so,how much.
In passing,I will say that I'm very pleased with the results.





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