I know this is an old thread but I felt compelled to post since I know people that own Martin Logan electrostats typically will keep them forever and there's a chance others may read this post and have a similar bass sound issue with their Martin Logan bass response.
I have a set of Prodigy, they're basically very similar to the Odessy in that both models have dual woofers, albeit the Prodigy have dual 10" drivers while the Odessy uses an 8" and a 10", but both models were made using a very bad idea that drastically affects the way these speakers reproduce low bass tones. If tested, you'll find that they do put out bass sounds, but the way they do it is why they lack so much.
ML made a special circuit within the internal woofer crossover network that in their opinion is a built in room mode compensation circuit that's aimed at reducing gain in the typically enhanced 70Hz to 90Hz range that rooms can enhance those tones through room engaging that adds a peak to the sound. That would be fine if it was set up to turn it off when your room is not made ideally for that circuit to even work.
They went wrong by instantly assuming all rooms react the same to their speakers, now we all know that the chances of you setting these speakers exactly as ML did when they tested them is unlikely and more importantly the room they used is exactly the same as your room. The way speakers interact in any room is a direct result of how the waves move throughout the room and moving s speaker a inch or toeing them can affect the room mode. So each room needs to treated as its own subject and it's impossible to predict this factor prior to setting them up and running some sweeps. That's just how this process is done and an eq is then used to see if you can make the needed corrections to achieve a more linear response.
When ML did this the purposely are causing the cancellation of bass tones, how this is implemented is dependent on the placement and the room shape and size, what is delivered through their circuit is not going to have the same affect on the way the bass is projected into the room. Now this is the main point I'm trying to make, through their cancellations, I noticed right away that there is plenty of bass when I stood directly between the speakers (at a 90 degree angle between the sides of the speakers) and if I moved more in front of the speakers, the bass power diminished. When I got to the listening position there was a distinct void in the bass but I could hear it if I left the room.
Outside that room or even outside my home I could hear the bass vibrating the structure but as I got closer to sitting in my couch, I heard less bass, dramatically less.
Since ML only offers what they call a bass boost (which is simply turning off a resistor set to reduce the 50Hz output) that can be disengaged but it does nothing to boost anything, it's a cut that you're turning off. Using this info I had to question what's really being done in their crossover network they used on the woofers. I also own a set of Aerius that I owned before the Prodigy and I felt they were not correctly made and lacked the bass power I had expected from any set of speakers I could make myself. Since I have spent years working with JansZen Electrostatic panels and making my own configurations using multiple panels and dual woofers and was able to make a set of speakers capable of testing flat from 24Hz to 24KHz. They sounded fantastic but I lost them in a small fire that got hit enough to melt the panels, the woofers were fine just had soot covering them as well as wet drywall and insulation from firemen.
When I moved back in I picked up the Aerius and that's when I decided to modify them to help them get closer to what I had made and I noticed they needed help in the bass but also had poor imaging and staging due to the confusion of the rear waves being incomplete and was dispersed unevenly due to the curve of the panel that caused the waves to cross in all directions being bounced around before hitting the rear wall behind the panels. I couldn't easily correct that issue but I felt that it could be reduced if the rear waves had the full spectrum being reflected with the reinforcement of the waves coming from a single direct reflecting source that faced towards the wall. By installing a second woofer on a newly made rear cover and doing testing to find out which wiring and mounting if the new woofer would work best.
I used 4 new woofers I had laying around from my last JansZen project that never wee used. They were 8 ohms drivers and I decided to bypass the stock crossovers and use my active crossover again as I did with the JansZens, I had 2 matching QSC fanless amps and used one chanell on each input meaning the panels had a dedicated channel and the woofers had the other channel and they were set to crossover at 500Hz. The change was dramatic in both bass reinforcement but also brought the staging and imaging to a pin point perfection that I knew was possible. I was very content with those speakers and have a test plots that backs up the results.
A month later I found a great deal on a set of Prodigy that had an issue, since I've fixed a number of power supplies and rewired them to include 28 panels in my JansZen project I felt comfortable that I could fix the issue easily, I was correct and had them going in an afternoon. First thing I noticed was the lack of bass, this set has dual scanspek 10s that should be able to produce some deep bass notes, I found an issue with one dtivers tinsel leads being ripped off the wire terminal posts that was broken off the frame. I figured that happened while the last owner attempted to do repairs and gave up once that was broken.
I fixed it but it had more issues since it lost more bass after repairs and I checked all wiring and looked at the schematic. I saw the notation of the curcuits built in room mode compensation and decided to bypass the woofers crossover entirely again using the electronic crossover, I ran tests to find the best wiring set up and I immediately noticed a dramatic restoration of bass, the test showed no roll off until 10Hz, I was seeing a steep decline at 40Hz prior to the bypass.
I only need a small reduction in the 80Hz to 100Hz range, the Aerius still had a smoother plot but the Prodigy have a more pronounced projection from each source than the Aerius and cover a larger range of tones that makes for a more pleasing sound, but I have to say I had a hard time deciding which would remain in my system. You'd think that ML would learn to simply first make a speaker that had fantastic bass response before they start adding in bad ideas into their design. They seem to miss the mark on the bass every time.
These mods were easy and cost very little to do. The Aerius mods cost under $60 and was completed in an afternoon. The Prodigy cost me nothing since I had the crossover and amps, even if I had to buy them, the cost would be under $200 using good used pieces. Right now I'm powering the panels with a Carver Sunfire 300w x 2 amp and the woofers sound best with a QSC GX5 at 750wpc x 2 @ 4 ohms , the woofers are wired at 2 ohms but can be wired to run at 8 ohms if wired in series. My amps are rated at 2 ohms even if bridged so I went with 2 ohms on the woofers just to make sure I have the bass I want.
I've tried other amps on the Prodigy, I've tried the Sunfire on the woofers and it did not sound nearly as good as the QSC, I also tried a Carver PM950 on the woofers and it can't match the QSC. I have a large stack of SS amps in both AB class and H type amps and I've found the best way is with the Sunfire on panels using either output (voltage or current) and the QSC just has the cleanest noise and hum free sound on the woofers. I keep going back to it after trying many others. I'll guarantee bypassing the woofer crossover will make a dramatic increase in how the bass tones are projected toward the listening position, making those speakers a real compliment speaker at any cost, before I did that, I could not see how they were selling them @ $10k, I know I could put a better speaker together for half that. If anyone sold theirs due to this issue, all I can say is the fix was so easy you'd kick yourself for not modding them. They are truly exceptional now.
