"Audio Empire" wrote in message
...
On Wed, 30 Nov 2011 15:51:09 -0800, Arny Krueger wrote
(in article ):
"Edmund" wrote in message
...
On Tue, 29 Nov 2011 23:27:46 +0000, Arny Krueger wrote:
"Audio Empire" wrote in message
...
What I have found is that two subs are always better than one,
however.
I would trot out a little logic of rhetoric and point out that any such
global statement is more than a little suspect.
I've heard two subs sound worse than one, and I've hard more than a few
cases where two subs and one sub sounded different, but could find no
preference for either.
I know that the conventional wisdom has it that a single sub, with
all of the
system bass below about 200 Hz or so summed to one channel, is
sufficient because low frequencies are non-directional,
That's way off, because it is well known that subs crossed over much
above 85 Hz can generally be located in the room.
I have tried my two subs in
all possible combinations: both subs summed as one, one-channel (first
the left, then the right) operating only, and stereo bass. Stereo bass
ALWAYS sounds better in my listening room whether I'm using one of my
woofers monaurally or both of them monaurally.
Well, if you are crossing them over at 200 Hz, no mystery. Come back
after a few weeks of listening with them crossed over at say 50 Hz.
It's weightier (as one might expect)
and is more articulate and more spacious. I have also noted that even
though
most of the imaging cues for bass instruments originate in the bass
instruments' upper harmonics, that having the lower fundamentals
originate on
the same side of the soundstage as the harmonics does help with
low-frequency
placement.
Again, an obvious artifact of what seem to me to be very strange
choices
of crossover frequencies.
200 Hz doesn't seems strange to me at all, as a matter of fact it seems
quite right to me. Many speakers and certainly surround stuff don't
produce
much noise under 200 Hz let alone music!
200 Hz is a possible but relatively high crossover frequency for surround
speeakers.
I checked the specs of a number of surround receivers and processors and
found that a typical selection of crossover frequencies might be:
40Hz / 60Hz / 80Hz / 90Hz / 100Hz / 110Hz / 120Hz / 150Hz / 200Hz /250Hz
The above was taken from the specifications for a mid-range Denon
reciver,
but is typical for modern receivers and surround processors.
Thus, 200 Hz is at the high extreme end of the range of usable crossover
frequencies for surround speakers.
Where did the idea come from that anyone in this discussion was using (or
even contemplating using) 200 Hz as a crossover frequency for a subwoofer?
200 Hz came from a post made here by "Audio Empire" on 11/27/2011.
200 Hz was only mentioned as the frequency that conventional audio wisdom
cites as the frequency below which bass is supposed to be sufficiently
non-directional (in a domestic listening environment) that a single
subwoofer
would adequately serve as the low-bass source for any audio system from
mono
through 7.1 surround.
The above is not a generally-accepted fact. The generally-accepted number
is in the 80 Hz range.
One example of literally 100s on the web:
http://axiomaudio.com/bassmanagement.html
"80 Hz
Why 80 Hz? Because deep bass below that frequency (the aforementioned energy
of the bass drum) is not directional; it's just low-frequency energy that
needs the big woofer of a subwoofer (plus its powerful self-contained
amplifier) to generate. So that's the process you trigger when you set your
center and surround speakers to "Small". The receiver's bass management
circuit routes the deepest bass to the subwoofer and all the upper bass and
highs to the center and surround speakers (and to the main speakers if they
are bookshelf models)."
I don't know if the most mentioned number is 75 or 80 or 85, or perhaps even
90 or 70, but no way is it even within an octave of 200 Hz.
My own experiences would qualify this number by noting that "non
directional" is dependent on what you think *directional* is. There are a
number of relevant variables including the spacing between the two sources
to be differentiated spatially, the room, and what the listener requires to
perceive the desired levels of sameness or different, and the program
material.
If you have two small direct radiators 12 feet away in a reverberant room
and with very little spacing, then even 200 Hz could in this extreme case be
called "non directional' If you have a subwoofer that is exactly between two
main speakers that are say 9 feet apart, and 12 feet away from the listener,
then perhaps even 85 Hz is "non directional" If the subwoofer is way off
center and much closer to the listener than the mains and the room is
well-damped, then 65 Hz might be a more reasonable number. Then there are
other issues like the actual coherency of the signal being listened to. If
we are listening to sine waves then the ear is more sensitive, while the
sound of a typical acoustic bass playing jazz at a rapid tempo is usually
far harder to distinguish.