Karl Uppiano wrote:
We don't perceive low
frequency directionality because given the spacing between our ears (as
opposed to the space between our ears) doesn't allow for much phase
difference at low frequencies.

Low frequencies can be well localised in anechoic conditions but not in a
normally reverberant room of reasonable size. I have taken part in blind
tests that indicated that you could cross over a woofer at 120 Hz without
being able to tell where it was, provided it was not very near the listener.
In fact you could push it up to 160 Hz although I think that was the limit.
The tests were with speech and music, using a normal stereo pair of speakers
for the higher frequencies.

The test system did have a very steep cut-off filter, but this was over 10
years ago and I have forgotten what the slope was. The effect of distortion
in the speaker is also very important (and inevitable) so it is a good idea
to have acoustic attenuation of frequencies above the nominal cut-off by
pointing the woofer at soft materials.

--
Tony W
My e-mail address has no hyphen
- but please don't use it, reply to the group.

"Tony" wrote in message
om...
Karl Uppiano wrote:
We don't perceive low
frequency directionality because given the spacing between our ears (as
opposed to the space between our ears) doesn't allow for much phase
difference at low frequencies.

Low frequencies can be well localised in anechoic conditions but not in a
normally reverberant room of reasonable size. I have taken part in blind
tests that indicated that you could cross over a woofer at 120 Hz without
being able to tell where it was, provided it was not very near the
listener.
In fact you could push it up to 160 Hz although I think that was the
limit.
The tests were with speech and music, using a normal stereo pair of
speakers
for the higher frequencies.

The test system did have a very steep cut-off filter, but this was over 10
years ago and I have forgotten what the slope was. The effect of
distortion in the speaker is also very important (and inevitable) so it is
a good idea to have acoustic attenuation of frequencies above the nominal
cut-off by pointing the woofer at soft materials.

I did not mean to imply that there were any absolutes in LF localization
ability by humans. It seems to drop off gradually, and of course relative
phase *and* loudness play a part in what we hear in each ear. Confounding
factors, such as harmonics and other noises coming from the LF driver can
provide clues as well (perhaps more easily discernable in an anechoic
space?).

As for whether blending LF to mono for vinyl is audible or not, might have
been less important than practical considerations related to making playable
records. Digital audio certainly does not have that constraint. I don't know
what current practice is for routing LF when mixing for CDs.

Karl Uppiano wrote:

As for whether blending LF to mono for vinyl is audible or not, might
have been less important than practical considerations related to
making playable records. Digital audio certainly does not have that
constraint. I don't know what current practice is for routing LF when
mixing for CDs.

There is a plug-in called mono around, and reducing the channel separation
in the low frequency range can be useful with recordings made with some
distance between microphones. It will however also change the perspective
experience for those that play the recording on full range stereophonic
systems. The trick is also quite useful to reduce rumble from records, be it
from playback or from the cutting ... it is one of my posted enhancement
requests for Audition that the functionality should be integrated and it has
so been since way before I heard of the - admittedly useful - third party
USD 99 plug in (or stand alone, can't remember), a bit costly compared with
the upgrade price for the entire Audition package ...

Kind regards

Peter Larsen

Don Pearce wrote:

I was interested in how heavily modulated vinyl could be, so I popped
an old record (Long Hot Summer Night, Jimi Hendrix, Track Records
1968) under the microscope for a look. And what did I find? Two
adjacent grooves clearly broken into each other:

http://81.174.169.10/odds/grooves.jpg

Was this a really common back then, or is this kind of thing a rarity?

Hardly surprises me !

It's probably part of that allegedly sought-after 'vinyl sound'.

Graham

"Dave Plowman (News)" wrote in message
...
In article m,
David Nebenzahl wrote:
On 2/4/2009 9:10 AM Brian Gaff spake thus:

The worst I've encountered is the very audible signal from the
adjacent turn so to speak. I wonder what your sample had been played
on though.

What you're describing has nothing to do with vinyl; you're talking
about "print-through", which is an artifact of the tape mastering
machine feeding the cutter, where you can hear signals from adjacent
lengths of tape.

Dunno about the record industry but I would edit in leader tape to
remove any from the start of a track.

I think that was normal practice everywhere, except for places
that used the same tapes over and over again, but their material
was unlikely to go for cutting anyway.

Iain