FOR AUDIO NIRVANA
GLORY ---- PART TWO
first installment, I discussed some aspects of electronics relating
to matters audio. In this second part I will divulge a few unknown
or a least obscure things relating to the recording process. Firstly,
I would like to reiterate a previous statement: Stereo DOES NOT
exist in the real natural world. I really want to drive this point
home. All sounds in nature are created in MONO. However, as everyone
knows, mono has no depth, no dimension, and no presence. Therefore,
stereo becomes a necessary evil that at least provides us with
some semblance of the foregoing. It has been up to our ear-brain
link to fill in all the gaps of missing or out of kilter information.
Even though stereo itself is a lousy format that we have been
living with for some 45 years, it didn’t have to be that way.
There has been a mathematical derivation that could have been
provided for us right from the beginning had the engineering community
been smart about the whole process. Unfortunately, it wasn’t to
be but, that won’t be for long. Anyway, let me define for you
what I mean by the words dimension and presence.
is a quality that has 3 derivatives. First is the main aspect
of stereo which encompasses the lateral or left to right dimension.
The second aspect is the front to back dimension. The third derivative
is the one that is missing which is the vertical dimension. For
the most part we live on a flat earth wherein alll of our lives
and the events in our lives occur in the lateral plane. Also,
our ears obviously are on the sides of our head and not on the
top of our head and on our chin. Our human perception is much
more acute in the lateral plane than in the vertical plane. For
example, try locating an aircraft WITHOUT moving your head.
You will find it to be extremely difficult. Virtually everyone
looks up into the sky and tries to locate the plane with their
eyes and then, once located, it’s much easier to slightly capture
the sound direction.
recording, all of the information is recorded laterally and there
are no extra channels to capture the vertical information. There
is some savings grace due to psychological aspect of associating
high frequencies above low frequencies. That is why virtually
all loudspeakers have the tweeters at the top and the woofers
at the bottom. If you want to have a good laugh, try turning your
speakers upside down to hear what they sound like. You will be
very surprised to hear how weird they sound.
thing I want to explain is presence (my definition). This is the
aspect which determines your seating position. When I go to an
event, I want to sit right down in front—first row. I have several
friends however, that can’t stand to be that close. They generally
sit about 30 or 40 rows back. Now, if you are a recording engineer,
where do you put the microphones in order to satisfy both parties?
The answer is: YOU CAN’T. This is a problem of time and not amplitude.
You cannot fix this problem with the volume control.
part of this dimension problem involves the spacing between the
microphones. In the old days of wide spaced mikes (called stereophony)
the mids and highs were quite acceptable generally however, the
low freqs were really a problem. This occurred because with wide
spaced mikes the wavelength difference at low freqs caused multiple
eigentones and cancellations in the playback environment. Most
recordings tended to sound cavernous and boomy at the low end.
In order to solve this problem, coincident mike techniques were
developed and employed with the capsules virtually on top of each
other with angle spacing of between 110 degrees and 135 degrees.
This virtually solved the low frequency problem but now introduced
problems at the high end. For example, if the capsules are in
effect say about 1 inch apart, then that distance represents a
wavelength of about 10kHz. When played back with the speakers
say 8-10 feet apart, a gigantic hole is produced wherein one must
find the exact “sweet spot” in order to listen.
have been other techniques that have been used to help with these
problems such as the MS and crossed figure 8’s (a Bert Whyte specialty).
But the problem really involves time and distance and not amplitude.
decades ago when I was faced with these kinds of problems trying
to record my Steinway grand, I was indeed frustrated. After pondering
this for quite a while, I devised a totally different concept
in mike technique. Firstly, I used a MONO center channel that
went through a low pass filter with a cutoff at 250 Hz. I then
placed a pair of mikes (in stereo) on either side that covered
the frequencies of 250 to 500 Hz. These of course fed two bandpass
filters which went to a summer on each channel. The distance on
either side of the center mike was exactly 3 feet. I placed then,
a 2nd pair of mikes further outside to cover the frequencies
of 500 to 1000 Hz. These were placed exactly 1.5 feet outside
of the first pair and their outputs went through a corresponding
bandpass filter and into the summing circuit. I then placed a
3rd pair of mikes exactly ¾ of a foot
to the outside of the 2nd pair which covered
the frequencies of 1000 to 2000 Hz with the respective output
going through bandpass filters to the summing circuit. Finally,
I placed a 4th pair of mikes exactly 4.5 inches outside
of the 3rd pair which covered the frequencies of 2000
Hz and up wherein their outputs went through high pass filters
to the summing network. I would liked to have used another pair
in order to make the last band 4000 Hz and up but I didn’t have
any more mikes available.
the least, the results were absolutely astonishing. Where I had
“mush” before where everything was very hard to distinguish, now
everything was crystal clear and the piano had absolute focus
and position. Obviously, this is a very difficult procedure however,
I wanted to prove a point. Correct mike location and technique
is THE absolute most critical aspect of recording.
that you can comprehend that a 2 channel system can only
approximate the exact position of a source of sound in space.
If you were to compare this with radio direction finding which
uses TRIAGULATION of three receivers to locate a source, it’s
easy to understand that a 2 channel attempt is going to fall short
of the mark. Another thing that should be understood is that on
an absolute basis, there is actually very little LEFT ONLY and
RIGHT ONLY information. Virtually all of the primary acoustic
information falls basically in between the loudspeakers. Yes,
I can hear the cries of “not true” coming from all those who believe
that the sound stage extends beyond the speakers to the outside.
This is of course true but, it is due to the reverberant field
and not the stereo composite signal itself. Notice also, that
I said very little and not none. As a matter of fact, the most
important information, for the most part, is located right in
the center or mostly in the central field. Obviously there is
no speaker there. This is what I meant by our ear-brain link having
to fill in the gap of missing information.
time ago Nakamichi tried to improve recordings by adding a center
fill microphone jack on their cassette decks. Sometimes this helped
but most of the time it didn’t mainly because the wrong microphones
were being used. In order for something like this to have even
half a chance, a thorough understanding of the “vectoring” of
microphones is necessary. With this 3 mike scheme simple cardioids
just will not work because there isn’t nearly enough isolation
between the mikes. What is needed here is super or even hyper
cardioids and they must be set up very carefully in order
to make sure that there is as little leakage between them as possible.
get to the meat of some suggestions and proposals. For the last
45 years or so, we have not had much choice in recording techniques
because we were limited to only two channels. Of course I assume
that everyone remembers the absolute disaster that befell us in
the 70’s. I’m speaking of course about “quad” sound. Anyone with
5 cents worth of brains could have or SHOULD have seen the lunacy
of this approach. As it turns out, I and others who tried to scream
loudly, were ignored. But unfortunately, after the millions of
dollars were wasted on this fool’s errand, we engineers had the
last laugh. Sorry ‘bout that. We are now faced with another idiotic
adventure by those who are proposing multichannel recording????
We haven’t conquered (and never will) 2 channel recording
and some people want to use 5 channels? This is absolute nonsense
for the following reason. All primary musical information COMES
FROM THE FRONT. It doesn’t matter what event you go to whether
a concert or a club etc., all of the musical information is
in front of you and not behind you. So the question becomes:
is there a better way? The answer is, you bet.
staring us in the face an incredible opportunity to have our cake
and eat it too with the introduction of DVD audio discs. These
discs have about 8 times more capacity than a regular CD. Why
not make proper use of this gift horse in the mouth. For example,
the 5 channels could be used in the following manner. Three for
the left, center, and right and a fourth for a high center,
and a fifth for a low center. This would give us that missing
vertical dimension. The playback speakers for the high and low
center would be placed accordingly and only have to be reasonably
acceptable in quality. To go a step further, many sets (say four
sets) of mikes could be located at intervals of say about every
ten feet with the first set being close miked, etc. Sound wild?
Well wouldn’t it be nice if you had an adjustment control on your
preamp where you could actually dial in your preferred listening
position. Incredible concept. Trust me, it’s doable. All it takes
is some industry leaders with GUTS.
a little anecdotal story is in order to prove some of the things
I’ve been talking about. Many years ago I did a round robin listening
experiment with a couple of friends. I had them over to my place
wherein I had selected 6 recordings that I considered absolutely
spectacular relative to miking, tonal color, etc. We played these
recordings and indeed they sounded tremendous on my system. We
then went over to the first friend’s house and my six records
sounded absolutely LOUSY. He then pulled out six of his favorite
records which indeed sounded glorious on his system. We
then went to the third friend’s house and lo and behold,
both my six and my first friend’s six recordings sounded just
terrible at our third friend’s house. But then he pulled out HIS
six favorite records which sounded incredible on his system. We
then came back to my place and wouldn’t you know it, both of my
two friend’s six recordings (each) sounded like absolute crap
on my system whereas my original 6 sounded great. The point of
all this is to show all of you just how much we are still in the
stone age and just how far we have yet to go. It’s going to be
a long and bumpy ride but hopefully someday this industry can
clean out the cobwebs of egotism and get down to some truthful
scientific discipline and come up with credible answers to this
very enigmatic audio puzzle.
to part three