Janis W1 sub-woofer

[Deleted User]

Here's an article that might be of interest to the younger CP folks:
"JOHN MAROVSKIS

In the mid nineteen seventies John Marovskis from the Bronx (New York) designed his extraordinary Janis W-1 and W-2 subwoofers. The story goes that he made some 50 cabinets before he arrived at the excellent sonic performance of his systems which have a flat frequency response from 30 to 100 Hz. (-3dB). He designed an electronic crossover module with a 60 Watt amplifier to go with the handsomely finished cabinet. This unit, the Janis Interphase, filtered the low pass section (Janis W1 or maller W2) and the high pass section (satellites) at 100 Hz. both with slopes of 18 dB per octave.
Another, most important feature was the continuous variable phase adjustment of the subwoofer (0-180º) in order to achieve a seamless and harmonious integration of subwoofer and satellites, independent of the subwoofer's position in the room.
In the nineteen seventies the Dutch importer of the Janis subwoofers in the Netherlands (Jan Endenburg of EngaSound) pointed out to me that optimum phase coherence could be obtained by a 12dB low pass for the Janis W1 and a 6dB high pass filter for the satellites as was achieved by the than cherished and famous Symmetry Electronic Crossover. But I found that the 18 dB slopes were much cleaner.

JANUS INTERPHASE + SUBWOOFER

Once in a while you read a rather negative review about the Janis subs. But these are always written by people who do not know how to use the Janis sub woofers. They make the mistake of using high current amplifiers (NAD, Rotel, Bryston, etc.) that get their power out of the large toroidal transformer instead of large capacitors. Toroidal transformers cannot deliver enough current and are soon exhausted because they need to deliver current directly out of the AC mains. In the past I have tried a Tandberg power amplifier for the satellites. They did not match at all. The sound of the Janis Woofers became realistically impressive only when using amplifiers that really go with the nature of the Janis Interphase. For instance when an Amcron power amplifier was used to furnish the power to the satellites. The Janis worked also perfectly well with mono blocks from French manufacturer Elipson. Just to mention some historical units. If you combine the Janis Interphase with the right amplification then the music will get its impact and slam. Not only when playing Tchaikovsky's 1812, but any record from your collection.
In recording studios in Hilversum (The Netherlands) Janis Subs were used in the nineteen seventies en eighties.
Another favorite bass system from the past was the Hartley sub woofer which was combined with de Decca Ribbon high frequency unit and the Quad electrostatic speakers (ESL). Impressive as well. (See: The Decca London Ribbon Horn Tweeter.)"
Enjoy, Ken

nguyendot

I saw these on craigslist the other day and came across that article...very interesting.

[Deleted User]

John's a great guy, and I hope still making sub-woofers and bass amplifiers. His father was a cabinet maker and he must have learned woodworking from him. I've enjoyed my sub for many years and continue to be amazed at how much it sounds like real music. It came with a frequency response graph and a distortion measurement. The bass amplifier has an adjustment that centers the woofer's voice coil in the gap. I can make a slight adjustment, of this control, and hear the change.
I believe it is a type of design where you don't actually hear the sound produced by the woofer itself. Rather you hear the sound of the air that is over the top of the woofer pulsing the air outside of the slot vent. The air over the top of the woofer is reactive as opposed to resistive. Normally the air in front of the woofer is resistive and the woofer creates pressure waves in the air. Under certain loading conditions the air is no longer resistive but becomes reactive, pulsed by the moving air. In turn, in the case of the Janis, the air outside of the long narrow opening is resistive and becomes the sound transmission medium.
Enjoy, Ken

gwh

http://oklahomacity.craigslist.org/ele/1718087258.html

EndersShadow

@KennethSwauger

I know this thread is stupid old but a buddy of mine just picked two of these up but doesn’t have the included crossover or amp for them.

Any recommendation on good pairings for them?

We tired to hook both up with what we had around (Carver C1 for preamp, Old EQ unit for crossover and highpass/lowpass, and M500t)...

and played around with placement but felt a little underwhelmed...

FTGV

The stock crossover had an 18db slope fixed at 100hz. Something like a mini DSP would work as should any decent amplifier. The cone offset correction will be hard to achieve without the original amp.