Parametric EQ?

So we have various parametric EQs floating around the forum, but none that are compact enough to use in an existing channel strip. Since som have graciously been working on compact compressor boards for existing channel strips, does anyone have a decent parametric EQ design that could be done the same way?

Eventually we could even have a DIY channel strip with the best of everything.

lets critique designs.

I have the schematic for the ssl9k eq but talk about some crazy pots you would need..

What about the Barry Porter net EQ? Don't expect a three-opamp design for a fully parametric one.

Samuel

multiple opamps are not a problem, just the physical size of the boards and the availability of the pots. I am looking for designs to compare right now. I have EQs with parametric mids and high/low shelving in the console but it sounds somewhat harsh in the highs and I also want fully parametric highs and lows too. I would like to make this small enough to fit in a channel strip with the compressor and a preamp too.

[quote author="Samuel Groner"]What about the Barry Porter net EQ? Don't expect a three-opamp design for a fully parametric one.

Samuel[/quote]

If anyone comes across a good source for center-tapped pots, please let us know.

Hey butta send me what you have, or if you have a schemo or a link to the schemo and I'll take a look.

Center tapped pot$ are part of the $$L9k i$$ue.. if you get my drift.. :green:

sounds like a plan to me, however i would go for even smaller than euro!

How compact? Some thoughts on this:

I looked into doing a 12-pot EQ in as small a space as poss. quite a while ago, & it is not easy. Also a pain in the butt to operate, the thought of trying to get my fingers around those tiny knobs to try & fine tune some EQ doesnt sound like a lot of fun.

I looked at 2 ways of designing this. You could stand the PCB upright, parallel to the front panel & mount the PCB pots either on the PCB suface, or drill a hole through the PCB & mount it using the nut on the shaft. Then use short links from the pot contacts to the PCB. This would mean a 3u case though to fit in the 100mm PCB.

Regards
Peter

what kind of pots would you like to use?

Maybe a push/pull pot would save some space for switches.

Can you use concentric pots (I think that's the term), or are those impossible to get in small quantities?

:? This whole thread is about the various factors around parametric EQs; yet no-one has mentioned how they sound.
I just have to throw in my two cents-worth and say that the only use of a so-called 'parametric' EQ in a console is to impress the punters. For serious recording it needs to be switched OUT all the time.
EQ can be used for two main purposes:
1) to correct for deficiencies in the sound from a microphone.
2) to alter spatial positioning; moving things forward and back in a mix.
The first use is not particularly 'musical', it's more a repair tool, and possibly digital EQ will do it adequately.
The second is artistic and subtle, and the EQ circuit needs to be artistic and subtle too! I have found that the only systems that work well are based around simple 'Baxendall' shelving curves, with possibly some low 'Q' mids added.
Just try using say the digital EQ in Cubase, with all its options, to 'sweeten' something.... it's a joke. :?
EQ is a great misnomer... what we really need is a phase corrector; but it would be too expensive, and too difficult to use.
Barry (Porter) designed some EQs, but much as he was a lovely lad and a very good friend, he fell into the trap of expecting that a set of beautiful curves would sound good, and it just is not so. :sad:

oh the humanity!

:green:

My room sucks but as of now I can't do much about it but EQ it.. :?

Oh, come on! Put up some egg boxes, bring in a sofa or two and close mic everything! :grin:

I did! that's why it sucks! :green:

seriously though.. my midrange is tweaked strangely and I can't seem to figure out how to get rid of it.. but you can clearly hear it in the room.. I've started to dampen and deaden parts of the room to try to figure out where it's coming from without choking the life out of it.

I bumped the Nemek EQ in The Lab, in case anyone wants to pick it up again. Hint, hint. :grin: :guinness:

i'll take a look.. :thumb:

How about this as an option to the center-tapped pot?

http://groupdiy.twin-x.com/albums/userpics/10071/CENTERTAP%20POT%20OPTION.pdf

The whole pot travel is switched either cut or boost. Another advantage is higher resolution.

Interesting! We could add this to a linear pot with a few external resistors and come out with a rough rev log centertapped pot and do the 9K eq..

ok here's the pot roundup for the 9k EQ if anyone is into BDSM..

1x 10k log dual
4x 47k revlog dual
1x 47k revlog TRIPLE
2x 22k lin dual centertapped
2x 22k lin centertapped


for ONE eq..


:shock:

I got omeg doing some quotes for some of these..