Agreed. I turned my 2s to 1+1 (after seeing the same thign done by Paul & Stan (PS Audio) in their Santa Monica shop. Added a bit of woofer support and passive bi-amp really polished them.
2+2 were only in my imagination.
dave
The Model 2+2 existed for a long time and used several iterations of the MK121 interface. The MK-121-2 and MK-121-2A are rectangular boxes and were used in earlier models. The MK-121-B and MK-121-C are square boxes, introduced when the 1+1 hit the market, which required a more compact enclosure to fit behind the panel. As built, there are minor electrical upgrades as the series progressed, but are otherwise very similar. Obviously, later iterations indicate a newer speaker, and hence a better chance of long-term reliability and sonic performance.
Any model with MK-121-C interfaces have both the greatly-improved Medallion transformers and the C-Modification. That you can count on. Then it gets a little less clear for the other versions, as many of them were later updated with Medallion Transformers, and some with both Medallion Transformers and the C-Mod. Interfaces with a BLUE Medallion label indicate Medallion Transformers only, whereas a RED Medallion label indicates both Medallion transformers and the C-Mod. Keep in mind that other non-factory authorized modifications may have been made, so buyer beware. And as discussed before, the C-Mod is easy to do, and can be applied to any MK-121, regardless of whether or not it has Medallion transformers.
Any model with MK-121-C interfaces have both the greatly-improved Medallion transformers and the C-Modification. That you can count on. Then it gets a little less clear for the other versions, as many of them were later updated with Medallion Transformers, and some with both Medallion Transformers and the C-Mod. Interfaces with a BLUE Medallion label indicate Medallion Transformers only, whereas a RED Medallion label indicates both Medallion transformers and the C-Mod. Keep in mind that other non-factory authorized modifications may have been made, so buyer beware. And as discussed before, the C-Mod is easy to do, and can be applied to any MK-121, regardless of whether or not it has Medallion transformers.
Why from 2 to 1?Agreed. I turned my 2s to 1+1 (after seeing the same thign done by Paul & Stan (PS Audio) in their Santa Monica shop. Added a bit of woofer support and passive bi-amp really polished them.
2+2 were only in my imagination.
dave
They are very different speakers, and you really need to audition any speaker before purchase, not only to verify they are working properly, but to make sure they fit your sonic goals. That being said, the Spectra 22 is a two-panel speaker, arranged side-by-side. The 2+2 is a four-panel speaker, arranged two below and two above. The imaging will be superior with the Spectra 22 (as with any Spectra model), but with four panels, the 2+2 will have better bass response and greater dynamic capacity.
You may also want to consider that any Spectra 22 will be built later than any 2+2, and sometime very much later than a particular 2+2, since the 2+2 existed in Acoustat's model line for so many years. This may impact your decision if reliability is important: the older the speaker, the greater chance of failure. I would carefully consider the vintage of the 2+2 in your decisions. Both are very good speakers that enjoyed a lot of popularity.
Oops, I just noted you also have the Model 1+1 on your list. This is a two-panel speaker, arranged vertically. As such, it will have imaging characteristics similar to a Spectra, but alas, with only half the radiating area of the 2+2. Bass response is a little shy (more so than the 2-panel Spectra 22) and many people opt for a subwoofer for good bass response.
In summary, none of these models is clearly superior in every way, and your decision should include factors such as age of each speaker, condition, price, and location (they are not easy to transport!).
From 2 to 1+1.
The needed bass help anyway and they sound better tall and narrow. I was thinking of adding 72” of Newform ribbon as a tweeter but ended up going in a very different direction.
dave
The Model One consists of a single panel per speaker, which uses a limited-range interface (MK-141) and requires the use of a subwoofer. The subwoofer supplied with the Model One was only so-so, and most have succumbed to surround-rot by now, anyway. Not a bad speaker if you can supply a better woofer, but still quite limited in dynamic capacity.
The Model 1+1 is a two-panel speaker, arranged vertically, which uses the full-range MK-121 interface. Bass response/dynamic capacity is much better than the Model One, but still can benefit from the use of a subwoofer. Imaging characteristics of both speakers are similar.
The Model 1+1 is a two-panel speaker, arranged vertically, which uses the full-range MK-121 interface. Bass response/dynamic capacity is much better than the Model One, but still can benefit from the use of a subwoofer. Imaging characteristics of both speakers are similar.
Quite a bit of information here to dig through. I have a new to me set of Spectra 1100's. They appear to be later model, having the 15v transformers and the bias section red twisted wire "antenna".
Long story short... I performed the bais adjustment "method 2" and could only get a max of 25 vdc, i set both to 22vdc so they would be the same. I have an output discrepancy in the woofer section. one woofer is definitely lower output. and seems to be crossed over at a different frequency than the other (lower) thus the lower output. since the louder one appears to be producing a wider freq range.
Is the inductor, resistor and electrolytic cap on the amp/banana plug input board the crossover for the woofer section?
When I play just the panels. output seems even and I get a good center image.
Any help would be appreciated.
Long story short... I performed the bais adjustment "method 2" and could only get a max of 25 vdc, i set both to 22vdc so they would be the same. I have an output discrepancy in the woofer section. one woofer is definitely lower output. and seems to be crossed over at a different frequency than the other (lower) thus the lower output. since the louder one appears to be producing a wider freq range.
Is the inductor, resistor and electrolytic cap on the amp/banana plug input board the crossover for the woofer section?
When I play just the panels. output seems even and I get a good center image.
Any help would be appreciated.
If you are measuring only 20-some volts by method #2, and yet the panels seem to be playing properly, then I suspect your meter has a lower input impedance than the recommended 10-Megohm. That's okay, the important part is that you're able to adjust them to the same measured voltage.
Yes, crossover components for the woofer are mounted on the input cup assembly (removable from the rear). I suspect you have a defective or disconnected crossover component. The coil has been known to be subject to overheating when driven too hard. The coil intentionally has a resistance of 1.8 ohms to reduce woofer level to better match the ESL portion, but this does contribute to it's getting hot.
Schematic & board layout are attached.
Yes, crossover components for the woofer are mounted on the input cup assembly (removable from the rear). I suspect you have a defective or disconnected crossover component. The coil has been known to be subject to overheating when driven too hard. The coil intentionally has a resistance of 1.8 ohms to reduce woofer level to better match the ESL portion, but this does contribute to it's getting hot.
Schematic & board layout are attached.
Inductance is probably close enough (2.2 vs 2.3 mH) but you may find the need to put a 0.5 or 0.6 ohm resistor in series with the coil to reduce the woofer level. It depends on your tastes, really. Resistor should be rated at least 20-25 watts, and mounted so it has some free-air ventilation.