[Elecraft] CM-500 Response (was: Heil HC-4, HC-5)

[Jim Brown]

I said:

>> I suspect there's something wrong with the CM500 you have. 

On Fri, 2 Apr 2010 02:21:24 -0400, Joe Subich, W4TV wrote:

>It certainly does not appear to have any problem other than 
>being extremely "flat" to the point of muddy.  With heavy EQ 
>and aggressively cutting the bottom end, the CM-500 is capable 
>of excellent sounding audio.  However, I would not recommend 
>it for use with a transceiver that lacks the level of control 
>over transmit equalization provided by the K3. 

OK, look at it this way. Because of our ham club group purchase, 
I've seen or heard quite a few samples of this mic, and their 
response is well tailored for use in communications -- that is, 
rolled off low end, some breath pop and handling noise that needs 
more low end rolloff, and enough pre-emphasis around 3kHz that it 
doesn't need any more. That sort of response is not natural for an 
electret capsule -- it would be provided by external circuit 
components. 

Yours doesn't appear to have that response tailoring, and you're an 
experienced audio engineer who would know, so I'd say that the 
sample of mic you have is defective, perhaps missing one or more of 
the tailoring components. That wouldn't prevent it from sounding 
good with the EQ you've implemented. 

Consider this. The CM500 is sold by discount retailers for about 
$45 or less. That means they're paying about $35 for it. It's a 
pretty well built product, both headphones and mic sound very good. 
I've specified functionally equivalent products (Beyer, Sennheiser, 
AKG) for production intercom systems. Their cost is on the order of 
$300-$400. What's the difference?  1) Ruggedness  2) Quality 
control. My guess is that the CM500 comes out of the factory with 
little or any QC. Yours is not the first QC problem I've heard 
about. I corresponded privately with another member of this list 
who got a bad mic. It was quickly replaced by the vendor at no 
cost. 

73,

Jim K9YC