Specifications

Secrets Product Review
Velodyne SMS-1 Digital Drive Subwoofer Management System
Part II
December, 2005
Roger Welch
Set-up
The SMS-1 can be connected to an existing system in several different ways. I chose to
evaluate it for this review in the configuration that I believe will be most commonly used.
That is to control a single subwoofer in an A/V system, driven at line-level from the sub-
output jack of the SSP/receiver which performs all the bass management.
The manual provides step by step instructions that lead you through the set-up process,
although a certain amount of practice is needed to fully master some of the functions.
The balanced measurement microphone (supplied) is connected to the XLR microphone
jack on the front (or rear) panel, and placed on the back of your chair close to where
your head would be when listening to music or watching movies.
Next, either a coaxial RCA composite cable (supplied) or S-Video cable is connected to
the video output jack on the rear panel, and the other end to the TV or other display
device. A stereo coaxial cable (supplied) is also connected to the EQ output jack on the
rear panel, and from there to a spare analog input on the receiver/SSP. This is used by
the SMS-1 to generate the test sweeps used to measure the system response.
Finally, the sub pre-out from the receiver/SSP is connected to the input of the SMS-1,
and one of the LFE outputs is connected to the subwoofer.
Since the SMS-1 performs the functions so much better in the digital domain, it is
advisable to disable any functions on the subwoofer that modify the signal. For example,
the phase control should be set to 0° and any low-pass crossover disabled or set to the
maximum available frequency position.
You then turn on the receiver/SSP, the SMS-1, the subwoofer, the TV, and settle down
with the remote control.
For this review, the partnering equipment was my Theta David II DVD player, Theta
Casablanca III SSP, Krell power amps, and Martin Logan speakers. The subwoofer I used
was an early SVS 20-39 PC Plus in its native 20 Hz tune. I used an XLR balanced
connection from the SSP to the SMS-1, and a single RCA cable from the SMS-1 to the
sub. I connected the EQ Output from the SMS-1 to a spare analog input on the SSP which