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DIY Stompboxes => Building your own stompbox => Topic started by: Chugs on February 03, 2021, 06:39:04 AM

Title: Good Q for mid range EQ?
Post by: Chugs on February 03, 2021, 06:39:04 AM
I am experimenting with gyrator eq's on the breadboard.

A Q of around 3 is often used for gyrator based Bass controls but I am seeing a few different Q's for mid range controls when looking at existing schematics. At the moment I have a Q of 1.7 with a 720hz Mid control.

Any suggestions or preferences for a good Q to start with for mids?
Title: Re: Good Q for mid range EQ?
Post by: iainpunk on February 03, 2021, 06:56:40 AM
a 'good Q' depends on the aplication, are you going for a variant of the chainsaw sound, like the HM-2 with everything on max? are you going for something more subtile? overdrive, distortion or fuzz?
for an overdrive, you should definitely stay under the 2, for a distortion or fuzz, you can go to higher values to get a coqued wah / chainsaw sound

in the end, its truly a aesthetic choice, and i recommend experimentation to match with you other gear!

sorry for this vague non-answer
cheer, Iain
Title: Re: Good Q for mid range EQ?
Post by: Chugs on February 03, 2021, 07:11:48 AM
Thanks, just experimenting so far.

I guess I am looking for something not too extreme, but noticeable enough as an effect.

So far I discovered a Q of higher than a Q of 3 sounds too pronounced, focused. (Not looking for fixed wah type of sound.) Q of 1 sounds too broad.

Guess it also depends on how many bands of eq you have setup. I just have Bass and Mids but if you had a few different bands like a graphic eq you would want more focused Q from each band but if there is if there is only one band for Mids range than a bit broader Q.
Title: Re: Good Q for mid range EQ?
Post by: antonis on February 03, 2021, 09:02:12 AM
In the cost of a pot you can have variable Q..  :icon_wink:

(https://i.imgur.com/KIzB3qj.jpg)
Title: Re: Good Q for mid range EQ?
Post by: Rob Strand on February 03, 2021, 05:28:30 PM
QuoteAny suggestions or preferences for a good Q to start with for mids?
Most EQ circuits have a proportional Q behaviour.   That means the Q gets higher as you increase the boost (or cut).
So if you design a circuit for a design Q=3 at 15dB it will end up being Q=2 when set to 12dB and Q=1 when set to 6dB; all very roughly as in reality the Q is not exactly proportional to the gain.

I find a Q of around 1 to 1.2 at 12dB fairly workable.    Going to say 1.6 is OK but just starts to get a bit of narrowness.
Title: Re: Good Q for mid range EQ?
Post by: iainpunk on February 03, 2021, 06:44:37 PM
i build a low gain fuzz once, which has a mid boost knob, the Q was 7 at max boost, 31dB, which is fun if you dislike your audience, or really like death metal.

cheers, Iain