Speaking of mic mods: CAD M179

[Chris Rossi]

Speaking of mic mods anybody have anything for a CAD M179? Mine has
noticeable scratchy edgy distortion in the high end, right around the
breath frequencies on voice. It's been sitting in my closet unused
for the better part of a year. I wanted to make sure it wasn't broke
before ebaying it, if I went that route. Anyway, yesterday I borrowed
a friend's M177 just to see if I had a lemon mic I should send for
repair. (M179 is multipattern version of M177.) His mic had more or
less the same response although his was less pronounced, a little
tamed, compared to mine, without the big obvious peak. They aren't so
differnt that I can conclude mine is broken, but his does sound
marginally better on the top.

Assuming the capsule isn't causing this distortion, there ought to be
a way to clean up the electronics? (I don't really have a good way
yet to measure the distortion or freq responsce, but my ears are
telling me it's there.) Any electronics experts looked inside this
one? I'm still at the build stuff from a recipe stage in my
electronics skills. I'm not going to crack it open and go, "hey, i
could do this and it would sound better." maybe someday.

FWIW, playing around last night, I did get a decent acoustic guitar
sound out of this thing. It was nice to flip it to omni and get rid
of proximity effect for once. On that source the distortion didn't
seem to make big difference. It's the first thing I've found this mic
gives a usable signal on, so I actually have a reason to keep it now.

rossi

[David Satz]

Chris,

I haven't heard the particular CAD microphones that you mention, but they
are among the CAD models which require much more current from a preamp or
mixer's phantom power supply than most other condenser microphones do.

I record most of the time with Schoeps microphones that draw 4 - 5 mA
from a 48 Volt supply. I've found that there are plenty of preamps
(especially low-cost portable units with wall warts) that can't supply
that much current--and many CAD microphones, including yours, require
_twice_ that amount! When a microphone is "underfed" it will not sound
right, and will almost certainly begin to distort well before it should.

So before you sell off your microphone, you ought to check whether the
phantom power circuit in your mixer, preamp or whatever else has the mike
input is really supplying 8 mA. What exactly are you connecting this
mike to? Maybe it's something that I've tested here. As I said, in low-
cost equipment it would be quite unusual if the power supply were adequate
for feeding an 8 mA microphone, let alone two of them.

But I also have to say that the polar response diagrams for these two CAD
mikes are not particularly impressive. They look as if the sound of the
microphone would vary considerably if you address it from even slightly
off axis. There's always some room sound in any recording unless you
work outdoors or in an anechoic chamber--and uneven polar response means
that off-axis (room) sound will be picked up with highly "colored" sound
quality.

When shopping for microphones, response diagrams may not tell the entire
story but often they can tell you a lot if they're honestly drawn. But
the polar diagrams are the ones which many people never quite bother to
learn how to read, unfortunately.

If you are serious about microphone modifications, I'd recommend getting
in touch with Jim Williams of Audio Upgrades (www.audioupgrades.com). But
if you determine that the sound you're hearing is really the sound of your
microphone working as designed, you could save yourself a lot of trouble
by starting over with mikes that have flatter frequency response and
(especially) smoother polar patterns.

Please don't fall for the myth that bigger microphones automatically have
better sound for vocal recording. When I look at a mike like this one,
I think it may have been intended to impress first-time buyers with its
sheer size. But if so, that's only a marketing charade--as you may be
finding out.

--best regards

[Chris Rossi]

(David Satz) wrote in message >...
>
> So before you sell off your microphone, you ought to check whether the
> phantom power circuit in your mixer, preamp or whatever else has the mike
> input is really supplying 8 mA. What exactly are you connecting this
> mike to?
>
RNP. I don't know how much current it can supply to phantom but I'd
be really surprised if it wasn't enough. It would be easy to call
Mark and find out. I'm under the impression that the "standard" is
10ma. Seems like anybody selling a phantom supply that can't do at
least that is selling a broken piece of gear.


>
> If you are serious about microphone modifications, I'd recommend getting
> in touch with Jim Williams of Audio Upgrades (www.audioupgrades.com). But
> if you determine that the sound you're hearing is really the sound of your
> microphone working as designed, you could save yourself a lot of trouble
> by starting over with mikes that have flatter frequency response and
> (especially) smoother polar patterns.
>
that's real money to get mr williams to do it. i don't know about
throwing good money after bad here.

>
> Please don't fall for the myth that bigger microphones automatically have
> better sound for vocal recording. When I look at a mike like this one,
> I think it may have been intended to impress first-time buyers with its
> sheer size. But if so, that's only a marketing charade--as you may be
> finding out.
>
eh. i just have a philosophy that it's a tool and my ears will tell
me what it's good for. i bought because i had heard good things about
them and managed to win one for half new street price on ebay. i
actually had interpreted their presence in the mercenary inventory as
something of a tacit endorsement of these mics as well. i didn't know
if it would be as good as everybody said, but for the price i felt i
could risk it.

rossi

[David Satz]

Chris Rossi wrote:

> eh. i just have a philosophy that it's a tool and my ears will tell
> me what it's good for.

Excuse me, but that is such an _entirely_ reasonable attitude that I have
to ask: Are you're sure you've got the right newsgroup?

--best regards