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2 plus 2, Various, manual and modifications

Read more on the Acoustat 2 plus 2 in our home audio section

Bing Bergstedt2004-02-23 22:21

My System consists of the following:

Pre-amp - Audio Research Pre-amp SP6
Power-amp - Krell Stereo Power Amplifier KSA100
Tuner
ESL\'s - Acoustat 2+2, Model MK-121-2A, Serial Numbers 212205 and 212206, 220 - 240 vac 50hz
CD-player - Wadia 6 CD Player
Turntable - Lynn Sondek Turntable LP12

I hope that you are able to assist with the following requests pertaining to the referred 2+2\'s.

1. Owners manual - if you would kindly mail me a copy and include frequency response curves and/or figures.

2. Have you made any modifications to the referred generation specifically towards providing good bass reproduction? If so, what are these and can they be purchased as retro-fit kits for fitting by either the customer or service technician.

The 2+2\'s have over many years proven reliable and importantly given me great pleasure with my only criticism being the lack of good bass. I have tried the separate sub-woofer route (Janis) but with minimum success. My preference is to possibly upgrade the Two + Two’s and have them totally integrated. I remain an avid fan of Acoustat and look forward to receiving your reply.

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Andy Szabo2004-02-23 22:21

The owner\'s manual is now available on this site.

At one time, there was a factory modification for the MK-121 transformer interface. However, this is no longer available. Although not specifically aimed at improving bass reproduction, the Medallion modification did tighten bass response somewhat. I am not aware of any other modifications.

Mating a subwoofer to a planar speaker (electrostatic or otherwise) can be tricky, at best. Because of the very different dispersion and speed characteristics of a conventional woofer as compared to a planar speaker, it is difficult to make the transition seamless. Use as low a crossover frequency as possible, certainly less than 100 Hz for the 2+2, to retain as much of the electrostat\'s quality as possible. The slope and phasing of the crossover is also an issue, with not necessarily the same slope for the high-pass and low-pass. As a start, I might suggest a 12 or 18 dB/octave slope for the low pass, and a 6 dB/octave slope for the high pass. Beyond that, further experimentation with room placement is required.

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