Diode gate for kick mic

[Guitarist]

I've shoved in a passive Heil mic into the kick drum, but there's a ton of booom. So I had the idea add to the mic cable two sets of back-to-back diodes ala Peavey's gate trick. Any thoughts of which diodes would work?

thanks, G.

[olddawg]

I used to put plain old low voltage rectifier diodes across the inputs of electronic crossovers I built decades ago. I used 4 diodes. That would clip any signal to ground over about 1.4vp. Any silicone diode in series like you plan on doing will not conduct until the output of the mic is about .7v (700mv). Does the mic have that much output? Why don't you you simply use the pad on the channel input of a mixer and adjust the eq?

[darkfenriz]

It's a bad idea.
First It may or may not work as desired depending on mic preamp intput impedance.
Second when it works it will distort unpleasantly.

EQ and compander are your friends here.

[Enzo]

Peavey's trick carves a tiny bit out of a large signal to reduce random noise. Putting diodes in your mic line would carve a large part out of a tiny signal. Peavey hit a large nail with a small hammer. You are proposing hitting a tiny nail with a large hammer.

Boominess is not a noise signal riding the music anyway. Boom is from resonances and bottom end. Instead of shoving the mic into the kick drum, try putting it outside facing the head.

[J M Fahey]

YouŽll need a "real" and *fast* noise gate, which can be emulated with a compander and some setup experimenting.

That said, and for the heck of it, you might protoboard a raw diode noisegate and listen to it.

It will distort of course, it will add a certain "krrakkk" or "brrapp" sound to drum beat attack, BUT it might be "good/interesting" and actually help drum kick be more "defined" and cut better in the mix.

Ugly? .....
It would be Žorrible if used to clean, say, a guitar chord or similar, but a drum kick is that, a kick, it carries "timing information" rather than any melodic value.

Might be comparable to classic Hammond "dirty contact click" which in Digital emulations is *added* to actual note to make it more believable, or pressing a thumbtack into a piano hammer .

One problem is that on a real noise gate you have the signal level you have, and you change trigger level at will; but in the diode gate threshold is fixed , it will chomp anything under 700mV so, to get the proper hammer-to-nail ratio as Enzo says, since the nail is fixed (and large) at 700mV, youŽll need to enlarge the hammer (signal) to even higher value to make it work.

IŽd protoboard an Op Amp gain stage , capable of turning your kick drum signal into , say, 3 to 10 V RMS , follow it with a couple antiparallel diodes in series with , say, a 10k pot , Audio/Log preferred if possible, and continue with signal taken from its wiper.

In 30 minutes you can have the answer, and post some MP3 here if you wish.

[Guitarist]

Thank you gents for the good advice. I often laugh at the sense of humour and idioms techs have eg. "small nail big hammer". Our band is so far stuck with a super basic mixer and the only quick way this would work is as an insert cable using low turn-on diodes. It was a thought... I'm not to great with OP amps unless swapping them, sorry Mr. Fahey. EQing has helped some.
I have an Amptweaker (James Brown) pedal with the diode noise gates and they work killer especially with some pickups (SD hot rails and a Rio Grande) that are prone to feedback - shuts 'em down! I do play loud sometimes, and will again tonight at the pub, oh yeah
Hope your enjoying the holidays..!

[Mick Bailey]

A long time ago (late 70s) I had a schematic for a single transistor noise gate. I've repeatedly searched on the web for a similar circuit and can't find anything close. It had a threshold pot and maybe 6 or 8 other components and worked really well, though I recall it gave slightly less than unity gain.