# Is white noise when the volume is cranked normal?

Discussion in 'Amps and Cabs [BG]' started by Trod, Apr 12, 2006.

1. ### Trod

I just got a used Iamp 500 . When I turn the main volume up to the 9-10 range I get a lot of white noise coming through my cab regardless of whether the tweeter is turned on or off. It is different from hiss. It's white noise and I can hear through the speaker. I can also hear noise and hiss when using headphones with the amp regardless the volume level. Is this normal? I dont remeber having that much noise on my other amps.

2. ### barthanatosInsert witty comment here

Feb 8, 2006
South Carolina
and...

3. ### niftydog

Jun 23, 2005
Canberra, Australia
Well, it could be the engineer in my talking, but that needs some clarification!

White noise is technically flat across the spectrum - the same energy is present at any given frequency point. Trouble is, there's twice as many frequency points in each successive octave (eg; 100-200hz compared to 200-400hz.) - so white noise is perceived by our ears as if it's skewed towards the higher frequencies.

Pink noise is logarithmically filtered by -6dB/octave. This means the same energy is present within any given octave - as distinct from white noise. Pink noise is therefore perceived by our ears as containing equal amounts of all frequencies within the range of human hearing.

It's not that it is closer to "actual music" but that it is an electronic approximation of what we perceive. "Actual music" is recorded and replayed using as close to a flat frequency spectrum as is possible. If "actual music" had a -6dB/octave filter applied to it, it would sound like crud.

Now, back to the question at hand!

Noise and hiss is normal, especially when you dime the volume out to 10! (I'm assuming 10 is the max?) It will vary from amp to amp, but unless it's abnormally or distractingly loud then I would hazard a guess that your amp is fine.

Mar 20, 2004