OFF: What hi-fi equipment do you use to listen to Hawkwind?

[Doug Pearson]

On Fri, 31 Dec 2004 11:48:07 -0500, Alastair Sumner
<alastair_sumner at HOTMAIL.COM> wrote:

>>One of the things that always intrigues me is why some music sounds great
>>on headphones but some doesn't, often because it seems to need that space
>>you refer to, to "breathe" somehow...
>
>Here's a short article about Stereo that I found yesterday. They make a
>distinction between multi-track recordings mixed down to two channels and
>true stereo recordings. I wish I knew more about this from a technical
>point of view because I've no idea what techniques are actually used in the
>modern music recording industry.

Recording in "true stereo" is one of those things that's an interesting
concept, in theory, but is questionable to implement as an actual process.
Basically, what it means is that *every* part of a piece of music is
*recorded* in stereo (i.e. with two microphones in such a way that the two
recorded signals make up an audibly-pleasing stereo image).  In the normal
recording process, this isn't possible because most instruments are recorded
using close-micing techniques.

For instance, the normal way to record a guitar that will be mostly in the
left channel in the final mix is to stick a microphone in front of a guitar
amp, record the guitar part to tape, and at final mixdown, pan the guitar
track towards the left channel.  The "true stereo" way to record this would
be to place two microphones in a room, one close to the guitar amp (the left
channel mic), and one on the other side of the room (the right channel mic);
at final mixdown, the tracks wouldn't have to be panned, because the guitar
signal is already in the left channel more than the right one.  In order for
this to be effective, the microphones have to be far away enough from the
guitar amp to pick up the "sound" of the room (the reverberations of the
guitar sound in the room), wheras with close-micing technique, the
microphone *only* picks up what's coming out of the amplifier, and any
reverberations are at too low a level to be perceptible.

Sticking with the guitar example for the moment, modern recording techniques
absolutely *rely* on being able to close-mic a guitar; moving the microphone
in front of a guitar amp a couple inches, or tilting it a few degrees can
*drastically* change the recorded sound (sadly, it appears that microphone
placement is becoming a lost art as more and more "Pod[tm]" people run their
guitars straight into some digital box into a computer; I'll say right now,
that for rock guitar, absolutely NOTHING beats the sound of a Les Paul
through a Marshall tube amp recorded with an SM57 [inexpensive
industry-standard dynamic microphone] onto analog tape, preferably through a
preamp with good transformers, like a Neve or API; no digital approximation
comes close to THAT).  So "true stereo" recording of an electric guitar
track isn't really a practical option (although adding room/distant
microphone signals to an existing close-miced guitar track can - depending
on the circumstance - greatly enhance a guitar sound, overcoming the main
problem with close-miced signals: the lack of ambience/environment/"room"
sound/reverb, which is otherwise done with some sort of artificial reverb).

There are a few applications where recording "true stereo" tracks makes a
lot of sense: anything through a rotary speaker (Leslie), small-to-large
ensembles like string quartets or horn sections, or massed backing vocals
(useful because it allows the placement of individual singers across the
stereo spectrum).  The latter is probably why the only "true
stereo"-recorded album that I'm aware of is the Beach Boys' 'Sunflower'.  To
quote:

"The songs on this record were recorded in true stereophonic sound; they are
not 16 monophonic signals placed somewhere between right and left speakers
blended together with echo, but rather total stereo capturing the ambience
of the room and the sound in perspective as heard naturally by the ear.
Although more difficult to perfect, this type of recording is far more
satisfying to hear, as will be demonstrated by playing this album."

>http://www.tnt-audio.com/topics/realstereo_e.html
>
>One area where I frequently hear the stereo effect is through my bog-
>standard Nicam Sharp tv. When you are sat a certain distance and angle in
>front of the two little loudspeakers the speakers themselves seem to
>disappear and you can hear voices and other sounds way over to the left or
>to the right. You can hear the whole space, not merely left channel, right
>channel and middle. Interestingly the effect seems to be much more common
>and pronounced on Channel 5 than it is on BBC 1 or 2. I've always wondered
>how this works through headphones because it seems like the angle of the
>listener in relation to the two loudspeakers is crucial.

Stereo perception through headphones vs. stereo perception from speakers are
two very different animals.  What works for one won't necessarily work for
the other.  For instance, the simple way to make "fake binaural" recordings
is to delay one channel of a stereo signal by a few milliseconds (true
"binaural" recordings [a fad in the late 70s, see Lou Reed's Arista LP's for
example] are those recorded with stereo microphones placed to simulate the
placement of one's ears - some studios have microphones for this purpose
that actually look like a head with mics where the ears should be).  Heard
through headphones, this creates a perception of "space" because it sounds
like the delayed signal is coming from farther away than the un-delayed one.
 However, when the two signals are blended together in the air, coming from
speakers, they'll interfere with each other, causing frequency cancellations
that make the music sound like certain pitches are lost, or that there's
some sort of weird "flanging" going on; this can also interfere with clarity
and make the sound "mushy".  Proper stereo reproduction with speakers is
much trickier than with headphones, since speaker angle, height, and
listener location relative to the speakers can have a large effect on the
listener's perception.

Blah blah blah ... ;^)

    -Doug
     jasret at mindspring.com