panasonic wm6a omni -> cardioid?

[cuibono]

I've been using home-brewed mics based on the panasonic wm61a capsule, and am looking to increase its many uses (look at linkwitzlab.com for a great example, scroll down to 'microphone'). The capsul is omni - I'd like to make a cardioid version. There seems to be two possibilities - perforate the back of the capsule. This might only cause bass rolloff though. The other is mounting it on the surface of a large sphere - a 1' diameter sphere might block sounds from one side above about 1k...

Any thoughts? I haven't seen it done, so maybe its not possible.

 

[Minion]

Makeing a Cardiod out of a WM-61 would be difficult and even if it weren"t the changeing to cardiod would totally mess with the frequency responce....

The best and simplest solution would be to just get a couple cardioid Mic capsules...There are some Nice Capsules out there like the TSB-165 ,which is a nice quality Cardioid Capsule that uses an external fet which can give lower noise because you can choose the fet you want and accurately Bias it...

there is also the TSB-2555A which is a large Diaphram electret condenser in cardioid which also uses an external fet and from what I hear makes an awesome studio quality mic....

Or even better if you want to expand your DIY Capabilities get a real Mic capsule (Non-Electret) and make a a Good studio quality mic ,Like maybe a Tube LDC or even a solid state LDC or maybe buy one of those Cheap MXL mics for $40 and mod it into a good useable mic....

Good luck

 

[MartinKantola]

Any thoughts? I haven't seen it done, so maybe its not possible.

It has been done and it is possible (not creating a real cardioid, but surely modifying the response exactly like you suggested).

Remember that with mounting it on a sphere you are changing the on-axis frequency response too. Check out how the Neumann M50/M150 is done...

Martin

 

[cuibono]

Thanks for the recommendations - I've seen those TSB capsules, but never tried them. Looks like its time.

I have a number of other mic's (diy LDC, SDC and ribbons), but the wm61a has so much to offer - very flat response, high SPL handling, decently low noise, is tiny, and cheap. Omni is great for a lot of situations, but lacks in others. I'll order a couple up TSBs soon. Too bad the smaller diameter models all have internal FETs...

 

[cuibono]

Hmmm, that M50 is pretty interesting - and interesting looking. That must mean that when I do binaural recordings, with the capsules right at my ears, there must be some HF directionality added. Hmmm...