Spectra 1100, Panels

Read more on the Acoustat Spectra 1100 in our home audio section

Jim Collins2004-11-04 19:26

Mr. Szabo, I have read most of your posts on Audiocircuit.com. Thank you for spending your time to assist others. I own a pair of Acoustat Spectra 1100\'s. I also have 2 extra pairs of just panels. I would like to add these to each side of the 1100\'s as follows: 1 panel on either side of the original 1100\'s panels as wings so you have a total of 3 panels on the left and 3 panels on the right side with the 1100\'s centered in the middle on each side. (That is wordy but I hope you get the picture.)
I am driving these through a NYAL Minuet in A and then out to a Citation V. My living room is small by US standards as I am in Japan. Are there any special wiring considerations or can I just connect the additional panels as per the color codes? Regards, Jim Collins

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Andy Szabo2006-07-15 12:10

Sorry, but I can’t recommend adding more panels to the Spectra 11 or 1100 interface. There are a couple of problems. First, the audio transformer is not designed to drive the extra capacitance of additional panels. Possibly it could drive two panels, but certainly not three. Secondly, this interface is not capable of driving low frequencies, so bass response would not be improved as it is in the larger full-range Spectra models. Note that some people have performed this sort of modification on the older pre-Spectra Acoustat models (and not without problems!), but that is an entirely different situation because, in those models, all panel areas are driven full-range. Because of Spectra’s sectored construction, and electrically-curved dispersion pattern, you can’t simply add side-by-side panels to make a bigger speaker. If I lost you with that explanation, think of the sonic image of the speaker as a painting or photograph. Adding more panels side-by-side would not result in a single picture that was three times as wide, it would instead produce three identical pictures side-by-side. Very confusing to the eye, and even more confusing to the ear (which is not so easily fooled as our eyes). One alternative would be to stack two panels vertically, to make a double-height speaker, with the two panels wired in parallel. This would keep the imaging characteristics intact. However, I am still not sure if the interface can easily drive the extra capacitance (the negative result would be rolled-off highs). Also, the woofer may not play loud enough, since you would have twice the panel area but still the same amount of woofer. If you want to go to all the trouble of trying this (with the understanding that it might not work), please let me know how it works out. I’ve always wondered about that configuration. If you want a bigger Spectra, the only proper way to accomplish this is to get a larger, full range Spectra model. The transformers and supporting electronics in those models are quite different, and vastly more expensive.

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