You may remember when I installed
treatments in the Secrets lab, back in the latter part
It worked very well, but one of the
things that I noticed was that the huge amount of bass that I had before
was diminished. Of course, much of what I was used to included all the
reverberation from the room. The bass was now tighter and cleaner, but
it was not as loud.
"Oh well," I thought, "it is more
This is part of the problem in high
fidelity. You really have to get accustomed to the idea that less is
more. In other words, reducing distortion and reverberation actually
means less sound. That is not easy to deal with at first. I have had
friends over to listen to great sounding systems, and they think that
something is missing. Yes, something is missing. The bad stuff.
This is particularly hard to deal
with in terms of bass. The reason is that distorted bass does not sound
bad. It can actually be appealing. Just listen to some of the cars on
the road at a stoplight. You can hear the pounding bass from big woofers
in automobiles a block away. Most of it is harmonic distortion, but
because the frequencies are so low, it does not bother the ears, and
consumers can crank it up as loud as they want.
We would never put up with that kind of
sound quality in the high frequencies. Such distortion is very unpleasant.
So, like many people, I had become
accustomed to loud bass, much of which was reverberation and corner
There I was, with more accurate bass,
but it was not as much fun as it was before.
In December of 2005, Roger Welch
Digital Drive Subwoofer Management System for Secrets.
It is one of a few
outboard subwoofer EQ components that let you
flatten the bass
frequency response in your room.
The SMS-1 includes a microphone which
picks up a sine wave sweep produced by the SMS-1, and generates a display on your
TV, via an S-Video connection from the SMS-1, which shows the response
as you add EQ in several parametric bands. The screen shot shown below
is from Roger's original review.
This type of presentation is called
an RTA, or Real Time Analysis. The SMS-1 generates a low frequency sine
wave sweep, through your subwoofer, and the microphone (which is placed in
your listening position) picks it up and transmits the sound back to the
SMS-1, and the curve is shown on your TV screen. You simply move the
sliders on the EQ bands until the response is as flat as you can get it.
OK, so, when Bruce Hall of Velodyne
released the latest version of the SMS-1 software, which lets the SMS-1
automatically adjust the EQ bands to achieve a flat response (within 3
dB), I decided to see if this product might help me with my problem.
I have two Velodyne F-1800 subwoofers
in the main lab, one in each front corner, behind and to the side of the
main speakers, as shown below. Since they are configured as stereo, I
needed two SMS-1s.
If you are wondering about the other
equipment in the photo, that is a BAT VK-5i balanced tube preamplifier
on the top of the rack at the left wall, with a Lexicon MC-12B SSP on
the second shelf, one of the Velodyne F-1800s in the left corner with
the SMS-1 on top, a Lamm M2.2 power amplifier on the floor in front of
the left Carver Amazing Mark IV Platinum ribbon speaker, a computer for testing
equipment, two McIntosh MC-1201 power amplifiers, then the right channel
Mark IV Platinum speaker, Lamm M2.2, Velodyne F-1800, and second SMS-1. The
component with the cables on top, on the floor at the right, is an Audio
Precision test instrument. To the left of the left chair are components
not seen in the photo, including McCormack CD transport and DAC, BAT
VK-500 power amplifier, and McIntosh MC-602 power amplifier. Behind the
camera are a pair of Carver Amazing Mark IV Silver ribbon speakers,
which are smaller than the Platinums.
Another equipment rack is on the way, for
placing a second preamplifier (Mark Levinson) and SACD player
(McIntosh). The BAT drives the McIntosh power amplifiers, and the Mark
Levinson preamp will drive the Lamms. So, there will be two complete
two-channel reference systems which sound slightly different from one
another. I have not decided on the speakers that the Lamms will drive. I
took this photo with a 17mm lens on a 35mm camera, so the perspective is
somewhat distorted. The room is not the tunnel that it looks like. Those
Carver speakers are nearly 6 feet tall, and a 100" motorized projection
screen will come down between them as soon as I can get the time to
install it. The projector will, I hope, be a three-chip DLP 1080p.
I placed the two SMS-1s one on the top of each
subwoofer. A photo of the left subwoofer with an SMS-1 sitting on top is
Right and left channel XLR outputs
from my BAT VK-5 balanced preamplifier were connected to the XLR inputs
on the SMS-1s, and the XLR outputs from the SMS-1s were connected to the XLR inputs on the subwoofers.
Room frequency responses before and
after EQ with the SMS-1 have already been published in the original
review. For the sake of this article, I decided to be a "busy consumer"
who does not have the time or inclination to go through the manual EQ
procedure with a TV connected to the SMS-1 and slide the parametric
bands all around to get the flat response while watching the response
change on the screen. I would be a consumer who wants to just connect it
up, turn it on, get a Self EQ, and go back to watching movies.
So, what I did was use the SMS-1
remote control to select the Self EQ sequence (by pressing 321), which generated the sine
wave sweeps several times, made its own adjustments to the EQ, and it was done!
I EQd each subwoofer separately, with
its SMS-1 microphone sitting on top of my listening chair, approximately
where my head would be.
Therefore, the left channel subwoofer
was EQd from its position to have a flat response at my chair, and the
right channel subwoofer was EQd from its position as well. The EQ was
different for each subwoofer, obviously.
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