by Roger Nichols
Do any of you remember when QSound first came out? About 6 years ago, Shelly
Yackus at A&M studios in Hollywood, invited some people over to hear
this new sonic process that would allow you to pan instruments beyond the
normal left and right limits of the stereo field. There were guitars that
seemed like they were sneaking up behind you. It was surround sound, but
without surround speakers. There was just the normal two stereo speakers
in front of the listener.
They system was very expensive and took tons of DSP horsepower. But it did
what no other system could do. The QSound system was beyond the reach of
mortal man, until now.
This has nothing to do with local anesthetics or trade unions, it has to
do with where in the stereo field a sound is placed. QSound best describes
the process as a super panpot. When you feed a signal into the QSound panpot,
the left and right limits are not the left and right speakers, they cover
the complete 180 degree field from directly off your left shoulder to directly
off your right shoulder.
For best results, you shouldn't try to use the dry signal with the QSound
signal while getting your feet wet with QSound. The QSound only signal will
allow you to experience the full range of the process without being watered
down by the original signal. After getting used to what QSound does, then
you may want to add some of the original signal to the mix. I liked some
stereo instruments when I panned one side of the dry signal to the right
(inside the speaker field, of course) and then panned the other side of
the stereo signal through the QSound to the left, beyond the left speaker
boundary. Pretty nice.
Another great effect was to mix all of the instruments through the regular
stereo pan pots, and then send the reverb returns through the QSound. The
reverb came out into the room instead of staying back behind the speakers.
I remember when stereo first came out, about 1959. Everybody's first stereo
album contained plenty of ping-pong effects to show off the new stereo spread.
Remember Enoch Light and The Light Brigade? No? Well, anyway, there is a
tendency to play with the new found stereo field by panning things around
during the mix. I played a joke on the artist when he came in to listen
back to a completed mix. The fiddle player was panned to the left for most
of the song. In the fade, the fiddle started moving toward the right, past
the right speaker and out the door. I added a door slam for effect. It took
us about an hour to stop laughing and pick ourselves up off the floor.
(Don't even think about it.) I am talking about the good spot between the
speakers that everyone fights over during playbacks. QSound is sensitive
to listener position. If you get out of the good center location, you are
not going to hear the effect as much as you would in the sweet spot. The
good thing is that a QSound mix does sound a little fuller than a straight
mix when you listen off-axis.
So, your album is already mixed and you think it is too late to use QSound?
Not by a long shot. QX/TDM is a stereo soundfield expander. It takes the
elements that have been panned to the left and right and moves them outside
of the stereo speaker image.
Many stereo enhancement processes that I have run across in the past have
done damage to the mono portion of the stereo image. The things that are
in the middle, like the vocal, the kick drum, and the bass. Sometimes mono
instruments that are panned off to one side of the center don't hold up
well after enhancement. QX/TDM does an excellent job of maintaining the
integrity of the mono sources in the mix.
There are three control sliders for QX/TDM. Center Drop, Spread and High-Pass
Filter.
Not a football play, but the control of the mono center information in the
mix. With the control set at Zero, the center elements pass through without
processing. As the Center Drop control is increased, the center information
is processed more resulting in softer or "thinner" center.
At the highest setting (0dB) full stereo processing is applied to provide
the maximum amount of stereo enhancement. At the lowest setting (-20dB)
the stereo width is brought back to the normal stereo field. You will find
that this control has more effect on program material that already has a
good stereo spread than a mix where most things are panned close to the
middle.
The high-pass filter acts like a crossover that determines how much of the
low frequency information is processed. High settings will allow more low
frequencies to bypass the processing. This may be necessary for a mix that
you want to maintain maximum mono compatibility. But, hey, that's your problem.
I all of my mixes to come back as a pure 1kHz test tone if anybody even
attempts to play them back in mono.
Basically, you play your mix, play around with the three knobs until you
hear something you like, and then you are done. I have not found a mix yet
that I could not improve the sound of at least a little with QX/TDM. I bet
you have the same results.