Using speaker as microphone..

[killersoundz]

I'm not sure most here at this forum have any knowledge or experience with this kind of thing or microphone preamps but I'll pose the question in case there is someone that can share their input...

Yamaha has this kick drum microphone called the 'sub kick', it's basically an 8" woofer inside of a drum shell wired up to a XLR jack to plug into a microphone preamp and use as a microphone. I have no personal experience with this and remain highly skeptical of it's usefulness.

However I am curious about the logistics of the device. Microphones typically range in impedance from 100-1000 ohms or whereabouts. I doubt they had a custom 200 ohm woofer made for the job. A microphone preamp probably isn't going to be very happy with a 8 ohm woofer attached to it? Ok so they probably used a transformer of some sort? Is it possible for a regular microphone preamp to have any sort of dampening factor over a woofer like a typical amplifier would? I would think that would be a problem.

I just saw a picture of this thing again and it always raises these questions

[Paul Carmody]

No need to pay for the Shure mic. You can accomplish the task with a bass guitar speaker in its cabinet. I'm surprised you of all people haven't tried it yet. I know some guys who've tried it, said it was OK. I'm not sure if they ended up keeping the tracks, though. In the end, I don't know if it's worth trying to outdo something as reliable as an AKG D112.

As for the impedance mismatches... I have no answer. I know that whenever people do it, they just use regular old 8" woofers in a cabinet.

[Whitneyville1]

All quality mixing boards will handle mics down to 20 ohms (or much less). My ancient RCA 5a's with the tiny tube in the bottoms, have an output impedence of 50 ohms, as do my E-V RE 55's. Audio-Technica sells in-line matching transformers for mics with .5 ohm impedences (boundry mics). Many people putting speakers in kick drums use band-aids or duct tape to "dampen" the cone. Shure, Electro-Voice, Audio-Technica, Blue, Rode, etc. all make high quality kick drum mics, in all price ranges.

[killersoundz]

Yeah I have an Audix D6 and a D112 so no shortage of kick mics. I have never experimented with using a speaker in this fashion because well frankly I think if anything it would have a use as a sound in jazz or country kick tones if anything and I rarely have any projects like that.

I just read a thread about it at 'gearslutz'. Apparently the impedance of the Yamaha Subkick is stated at 9 ohms or something. There are many who have made their own DIY versions, many just a raw woofer not in an enclosure.

After looking through that thread I got a worse feeling about this like it's another one of those things like the 'sonic maximizer' for guitar amps that everyone that spends the $100 for one raves about but the fact is they are tone deaf amateur guitar players.

I'm not going to pass too much judgement until I mess around with it myself but a lot of the pix on that thread worried me.



This guy says his DIY subkick "sounds great". The use of 4 microphones on the kick lets me know this guy is lost on how to simply get a good kick sound and is over compensating. He might not end up mixing all of them in and just picking and choosing (Mixing all those sources together would be a disaster, and if he does they would need to be time aligned, but the bleed from far miking the kick renders those 2 mics nearly useless in my opinion) ..... either way that's the whole vibe of that thread...

But anyways I wasn't really trying to get into if it sounds good or not but instead just if a regular microphone preamp is technically ok with it.

[tom_s]

One of the more surprising mics I ever tried on kick was an old Radio Shack PZM. This was live sound, not studio use, so I can't comment on self-noise from the captive preamp, but that thing went so low that I had to HP it with an outboard parametric to keep the subs from being ripped to shreds. This was long before DSP was available to the masses.

[Sydney]

The use of 4 microphones on the kick lets me know this guy is lost on how to simply get a good kick sound and is over compensating.

I would agree - heard plenty of great recordings using a single mic on the kick.

[Whitneyville1]

Geoff Emerick at EMI/Apple Abbey Road studios used a single AVG 365mm from Richard's kick drum on every session, but Starkey tuned his Ludwig to low "E" as he should and used a Rocket Speed pedal with a semi-soft felt head. "Loud" seems to be the only thing important today...

[lhwidget]

It seems like it would be a good way to get the really low freq sounds from the floppy movement of the drum head. I don't think it would respond to much else.

Then like tom_s mentioned, you'd need to HP it to keep the really low infra sonics out.

You could damp it with a .5Ω to what, maybe 2-4Ω? resistor across the speaker terminals. Better yet, a 10 turn 100Ω trim pot should be able to handle the speaker's output (for a while at least), then you could tune to suit your tastes.