[Bill Graham]

"GregS" wrote in message
...
In article , "Bill Graham"
wrote:

"AZ Nomad" wrote in message
...
On Wed, 8 Sep 2010 11:38:32 +1000, Mr.T MrT@home wrote:

I doubt you will find any stereo separation below 50Hz on any music CD
either, and definitely not on any vinyl source. So there is no
difference
between twin mono (real) SUB woofers, and true stereo for all practical
purposes anyway.

Unless your room is at least 50' wide, it won't be heard in stereo.
Wavelength for a 50hz wave is 22'. Let it bounce off the near walls and
it will definately not be stereo by the time it reaches the listener.

If you can hear where sound is coming from your subs, it is because of
harmonics above about 80-100hz.




Not sure how relevant this is to your discussion, but I play a trumpet,
and
I amplify my sound sometimes, so I can use special effects, and I have to
cut off anything below about 100 Hz, in order to eliminate the valve clunk
I
get when my valves return to their highest, "relaxed" position.....There
is
a lot of low frequency noise in any recorded band. Not just valve "clunk",
but guitar fretboard noise and other stuff like that.....I can get rid of
most of it with a low cut filter, but not all of it.....


I used to try and play trumpet. You could cut it off way higher I'm sure.

I have in the past used signal generators and try to find how high before
localization occurs. 70 Hz and below is pretty safe. Even my cheap signal
generator has .5% distortion, but my old HP does way better. Any
little noise can be localized, especially woofer wind or basket noise.


greg

Yes, I could cut it higher, but I notice a lot of devices have a built-in
filter that cuts the lows off at around 80 to 100 Hz, and, since there is no
music below there, that's about where I have my gate set....It's just that a
lot of devices and microphones advertize good frequency response down to
below 50 Hz, and I wonder why anyone would pay any significant amount of
extra money to buy such a device, when all you get at those frequencies is
noise anyway? AC hum is 60 Hz, and nobody would want to amplify
that.....Also, the highest note on a piano is only around 8 Kilohertz, so
it's pretty much a waste of time to buy devices that operate much above
that, either, but that's a whole different argument, and I probably
shouldn't open up that can of worms......It's just that when you are trying
to maximize your performance per unit dollar, you sometimes think about
these things.....I have five cats who can, (I'm sure) hear sounds in the
over 10 KHz range, but they don't appreciate most of the music I mess
with....:^)