Bought a Behringer deq2496, very cool stuff, hooked it up in RTA mode.
Found a ~20dB hump in the vicinity of 55Hz, what is that ?
When the background is quiet, the floor is about -90dB or lower except
the hump.
Is it normal ? it is 24/96 so I assume 48k bandwidth, -127 dB noise +
noise figure + gain of mic, anything else ?
Thanks!

Rus

J. Sun wrote:
Bought a Behringer deq2496, very cool stuff, hooked it up in RTA mode.
Found a ~20dB hump in the vicinity of 55Hz, what is that ?
When the background is quiet, the floor is about -90dB or lower except
the hump.
Is it normal ? it is 24/96 so I assume 48k bandwidth, -127 dB noise +
noise figure + gain of mic, anything else ?
Thanks!

Rus

It is probably hum from 60Hz mains radiating into your equipment. Just
ignore it or try to find out where it enters. Probably a ground loop.
If you are measuring with the mike and get a higher output, it might be also
a standing wave in the room. go to the middle of the room and see if it is
still there
--
ciao Ban
Bordighera, Italy

J. Sun wrote:

Bought a Behringer deq2496, very cool stuff, hooked it up in RTA mode.
Found a ~20dB hump in the vicinity of 55Hz, what is that ?


What is your floor-to-ceiling height in the listening room? Any room
dimensions approximating 10 feet?

-GP

Bingo!
After 2 weeks search, not ground loop, not noise injected
by refrigerator, not sure if it is related to standing wave because
no amp and speaker are connected, only background ambient noise picked
up by mic. But kind of believe tt is related to room dimension.
20dB hump is measured at the listening position/height, about 3.5'
from floor.
If I raise the heightc of mic, the hump goes down more than 15 dB at
7'from floor. floor-to-celing is 17' room dimension is W16x24L

any clue ? more info or experience ? Thanks!

Gene Poon wrote in message ...
J. Sun wrote:

Bought a Behringer deq2496, very cool stuff, hooked it up in RTA mode.
Found a ~20dB hump in the vicinity of 55Hz, what is that ?


What is your floor-to-ceiling height in the listening room? Any room
dimensions approximating 10 feet?

-GP