If you have a mechanical resonance of some sort, which sounds likely, it could
be getting stimulated by outside sounds such as passing cars or trucks. Or, as
Mike suggests, you may have an almost-feedback loop. Try putting the microphone
in a shock mount.

Peace,
Paul

Are you using a shock-mount on the mic? If not, maybe you should try
that. If you don't have one, try putting some padding/thick-carpet
under the mic stand.

Mike Putrino

"Brian Huether" wrote in message
...
Can you provide some links to these types of products? I am illiterate
when
it comes to roomm issues...


"Harry Lavo" wrote in message
news:f_6sb.124537$9E1.614288@attbi_s52...
Not everywhere. All he has to do is put a foam sound absorber or foam
covered baffle directly behind the mic. It is a figure-8 and has very
complete "nulls" to either side.


My advice would be to put the cabinet up on a bar stool or a road case [not
a table or a couch... or at least to the front edge of the table or on the
back of the couch], put the mic in front of it where it sounds good, then
drape a packing blanket, like the kind you steal from U-Haul on a mic stand
behind the microphone [with the blanket spread out like the length of a boom
stand that is parallel to the floor].

You're going to notice tonal changes with subtle movement of a 121... I have
found that things like rotating one as little as 5' will make a significant
difference. Turn the mic around 180', and you'll find that it gets
noticeably brighter... get a great tone from the amp, keep it off the floor
to minimize the reflections off the floor you're going to hear when you're
getting the tone but the mic won't hear coming from the speakers... put
something to deaden the reflected sound entering the rear of the
microphone... tweeze to taste.

Best of luck with the project.
--
Fletcher
Mercenary Audio
TEL: 508-543-0069
FAX: 508-543-9670
http://www.mercenary.com
"this is not a problem"