Graphic equalisers

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Dogtemple
Posts: 69
Joined: Mon Feb 21, 2011 7:14 pm
Location: Sussex, UK

Graphic equalisers

Post: # 57776Unread post Dogtemple
Fri Feb 12, 2021 7:42 am

Hi

I’m planning on building a lathe, I started this idea about ten years ago but there was very little to draw on. My first attempt was a pin stuck to a tweeter. Needless to say it didn’t work.

Anyway fast-forward to now and there’s loads more knowledge out there. I’ve been reading through this site pretty much solidly since Christmas.

Graphic equaliser spec is something I’m not 100% clear on. I’m trying to build with things I already have if they’re usable. I have this graphic equaliser, could anyone tell me if this would be suitable for an RIAA curve and other eq that might be needed? I’ll use a computer for this if needed but am trying to avoid that if possible.

It’s stereo and goes from 16hz to 32khz, +/- 12db, can reverse the eq as well, don't know if that would be of use or not? Would this do the trick?
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handcut
Posts: 252
Joined: Thu Oct 16, 2014 5:41 pm

Re: Graphic equalisers

Post: # 57777Unread post handcut
Fri Feb 12, 2021 9:56 am

Hey, hat's off to you going down the DIY route...

I wouldn't worry too much about producing an exact RIAA curve. Any open loop/non-feedback head is going to have all sorts of bumps & dips in it's response. Also, the lower portion of the curve will be pretty much taken care of by the 6dB/oct falling response inherent in these types of head (give or take). Your main concerns EQ wise will be controlling resonance and boosting highs. If you're only going to be cutting from digital files you'd be better off doing everything in software rather than with an octave-band GEQ, though down the line they can be useful for quick tweaks on the fly.
There's plenty of threads on here about measuring head response by cutting noise etc so I won't repeat it. Don't forget to use an inline fuse once you start cranking those highs...

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Dogtemple
Posts: 69
Joined: Mon Feb 21, 2011 7:14 pm
Location: Sussex, UK

Re: Graphic equalisers

Post: # 57779Unread post Dogtemple
Fri Feb 12, 2021 12:38 pm

thanks, probs will have to do it with a computer but it would be good to include this to have something I can fiddle with as it happens.

been thinking of using .500ma circuit breakers for the fuse aspect, just to make it a bit easier to live with.

got most of it figured out mechanically, luckily that part I'm quite good at and have a workshop with a mill and other tools at my disposal to make it relatively accurate.

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basplin
Posts: 68
Joined: Wed Jul 24, 2019 1:45 pm

Re: Graphic equalisers

Post: # 57850Unread post basplin
Thu Feb 18, 2021 6:04 pm

In addition to a RIAA, I use a DBX 31 band EQ for my cutting, which allows you to dial in the sound a little more. You could probably make the RIAA curve itself with one of these, but I haven't really messed around with it that much to be honest.

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