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TDL Electronics Monitor

Transmission Line Loudspeaker System

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TDL Electronics Monitor


The TDL Monitor loudspeakers employ full transmission line loading around a novel bi-radial bass unit, providing a greater piston area than otherwise could be accommodated.

The diaphragm is of solid polystyrene, with glass fibre reinforcing to both surfaces, which results in a light but very rigid motor system offering exceptional excursion and linearity.

Consequently, power handling in the bass is even greater, with lower distortion components.


Type: 4 way, 4 driver loudspeaker system

Frequency Response: 18Hz to 35kHz

Recommended Amplifier: 40W (minimum)

Crossover Frequency: 300, 3500, 13000Hz

Impedance: 8Ω

Sensitivity: 87dB

Bass: 1 x biradial 300 x 210mm

Midrange: 1 x 150mm doped polymer cone

Tweeter: 1 x 25mm magnesium alloy dome

Super Tweeter: 1 x 20mm dome

Enclosure: transmission line

Finish: walnut, black

Dimensions: 300 x 470 x 1150mm

Weight: 47kg

Price: GBP £1799 (1989)


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Reviewed Jun 07th, 2016 by HiFiAddict

The TDL Monitors came into my livingroom second hand about 10 years ago. They were goïng to replace my IMF Professional Monitors (for the people that know the IMF's, you will know that replacing them is not easy). But the TDL's were in fact the successors of the IMF's and a bit more 'housewive-friendly'...

You should know that the mids and the trebles of the IMF were beautifully balanced. Precise but soft and yet full of detail. Thanks to the 'supertweeter'. The bass (KEF B139 woofer) was rich but not allways completely under control.

The TDL's are a different story. The bass is much more solid, the mids are less coloured and the highs are very, very precise. One might say harsh when compared to the IMF's.

There were times I wondered if I did the right thing...

But it looks to me that it's not the speakers that are to blame but the recordings! My current setup is rather unforgiving. The TDL's just reproduce what is fed into them. Because, when I play recordings from Stockfish-records for example, it really sounds very real and controlled. But modern mainstream recordings are sometimes downright awfull.

So there you have it. I my opinion these TDL monitors are very good speakers that deserve very good source material and the best equipment you can get to make the most of your listening experience. 8/10 because there will always be beter speakers and the soundstage could be better. Also, placing them into a room is always going to be a compromise. Ideally they should be placed in the middle of a very large room to reach full potential.

The spreakers are driven by a set of AVM mono power amps (and sometimes a Quad 606 poweramp), a Van Medevoort preamp, a Van Medevoort CD-player, a Logitech Squeezebox Duet mediaplayer (FLAC only) through a PS-audio DAC. Straightwire, Audioquest and Audio-Technica cables.

With kind regards,


I think I'm lucky to own a pair of these rather rare speakers.



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