attenuator for speaker bassdrum mic?

[newmz]

I want to make something like the Yamaha Subkick microphone for recording my bass-drum. Check it out here .
It's very simple, wire the speaker terminals + and - to the hot and cold terminals if a mic socket and mount it somehow.
The main problem I anticipate after googling a bit is that the output will be very high and needs to be attenuated. I've also looked at that but all the information I find assumes you are working with mic impedances (around 600 ohms I think).
Can anyone tell me how to calculate say 10dB or 20dB attenuation given that the speaker has an impedance of 8 ohms (source) and my mixer is at about 2.6k ohms (input)?

[pinkmouse]

Looks fun!

Ok, the first thing I would do is build the mic, as by the looks of it, the output voltage will vary with the driver used. Once you have done that, then I would just try a standard 20K pot inline and see how that works.

Do you have access to a scope?

[AndrewT]

Hi,
a normal microphone diaphram is light compared to the weight of the case and stand. The mic case stays almost still as the diaphram responds to the air pressure changes.

Now, look at the weight of the cone and voice coil+former and try to convince yourself that the ratio of weights in this mic-speaker arrangement are comparable.
Even worse the offset drum casing from it's support is just waiting to resonate in reponse to air pressure changes.

You can do better than Yamaha.

[pinkmouse]

Andrew, I think you might be missing the point - this is a fun little project, that might produce an interesting effect. I don't think it will compare to accuracy of a D112, but it will be a lot cheaper.