Tom Simmons Memorial Design Number 2

The TSMD number 2 is a vertical line-array with ten drivers. These are not as bright as TSMD1 but the 3 inch drivers are very fast and have an excellent transient response. Also, twenty 3 inch drivers move a whole lot of air. Their presence or sound stage is exceptional! I began my listening tests with full orchestra and pipe organ material and the back wall of this room seemed to fade away into the orchestra stage or ranks of pipes. Then I tried some vocals and was delighted by their clarity, presence and centering. Their sensitivity is rather high so you can drive them with a very low-power amplifier.

Although we do use power tapering from top to middle to bottom, there is no crossover network so there is no crossover distortion. The only downside is the absence of much bass so a subwoofer is necessary. I have been listening using MaxxBass*, Big Bottom†, and Dan Ferguson’s dual voice coil servo system as these all use small enclosures. However, any subwoofer that can be set to a crossover frequency around 125 Hz should work well.


On-axis frequency response

Frequency response: 125 Hz to 20 kHz

Driving impedance: 4.2 ohms nominal

Power handling: 100 watts maximum (each ‘speaker)

Sensitivity: 97 dB (1 watt/1 meter)

Dimensions: closed box measuring 40.5 inches tall by 6.5 inches wide by 13 inches deep.

Weight: 46 pounds each, without the pictured stand.

Construction: 3/4 inch thick medium density fiberboard (MDF) with a 3/4 inch thick 13 layer birch plywood front panel; extensive internal bracing.

On the back of each speaker there is an etched aluminum plate as shown below at approximately full size.

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* MaxxBass is a psychoacoustic method for producing sub bass and is registered trademark of Waves, Ltd. More information can be found on the TDL® website at Products | MaxxBass or at (You can also refer to my article: “The MaxxBass Subwoofer” in the November 2004 issue of AudioXpress magazine.)

Big Bottom is another psychoacoustic sub bass technique and is a registered trademark of Aphex, Inc. Information is available at

 Information on the DVC servo system can be found on the TDL website at Tech Info | Speakers.