Taming/Damping Electrostat Backwave

Jamesswei's and Sidssp's sugestions are good ones from my experience with the old CLS's and the old Monoliths. I have owned 3 pair of Maggies as well and they benifit from the same thing. They all like space behind them. The fact that they don't have a cabinet is part of why they sound the way they do,no cabinet resonences to deal with. I have a friend who has Sound Labs and the sound is difficult when things get loud. His room is too hard and reflective. When you put on an acoustic jazz trio the potential is revealed. I have used the tube traps with sucess myself and they alow for some tuning where the results with permenent difusers are harder to predict. If you don't like the sound with the trap just rotate it or move it around until you do.

Sean, you might remember Harold Beveridge did exactly what you are proposing, and also went as far as using a bizare JBL style lens in front of the stat panel to control dispersion. I remember that they could sound quite nice but never heard them in a controlled situation. It always seemed to me like it was an approach that added some of the problems associated with box speakers.

I remember the old Dayton Wrights, the Koss electro stats, I had a boss with double KLH 9's, I also sold Quads and Acoustats at different times, they all have an aluring quality, you just need to acomodate their needs with some space around them and some room treatment. I had to go back to dynamic speakers from a stand point of practicality. Good luck and don't give up, you will be rewarded when you get 'em set up well.

Here is a horror story for Quad fans. I ran across some people while working in a HiFi shop who had inherited some speakers the knew nothing about. After talking with them I determined that they were Quad 57's. They told me about how they liked to watch the light show of sparks inside the speakers when the turned them up REAL loud. It about made me cry!

Has anyone ever tried mounting maggies or stats inside a wall that divides two different rooms, so that you get a monopolar wave in each? Just curious if anyone has tried it and what your results were, in particular whether the reflections from one room came back through the panel into the other.

Didn't Genesis or Infinity do something like this? Any one ever try using two pairs back to back to cancel the out of phase rear wave and create an in phase back wave? Just curious.

Room Lenses work wonders behind 'stats. DIY lenses using 5 or 6 tubes are even better or you might want to make noodle lenses. Check out Audio Asylum for info. I recently heard of using bi-fold louvered doors from Home Despot. These are said to be great diffusers and are easy to set up. Just fold them enough to stand up and place them behind the speakers. WAF might be a factor.

T Bone -

I'm pretty much going to say the same things Rives and Sidssp said, just in a different way. So feel free to skip over this post.

Assuming the "holy grail" is to recreate the concert hall experience, let's look at what's going on in the concert hall, and then see what we'd want to do with your SL3's to incorporate some of that into the listening room.

In the concert hall, first thing you hear is the direct sound of the instruments (duh). Then there's a considerable time lag - up to several tens of milliseconds - before the reflected energy starts to arrive. This reverberant energy is very powerful but also very diffuse, and lasts for several hundred milliseconds. This powerful, diffuse, late-arriving reverberant field is largely responsible for the rich timbre and enveloping sense of ambience in a good hall.

The backwave of your SL-3's can be your secret weapon in creating a better approximation of the concert hall than most speakers can.

Ideally, you want to position your SL-3's about 6 feet out into the room. This will allow adequate path length for the backwave energy to arrive late enough (10 milliseconds minimum) that it won't screw up the imaging, but will instead enrich the timbre and the feeling of ambience. Assuming your room's tonal balance is good, you'd want to use diffusion on the first backwave reflection points, to the inside of the speakers along the wall behind them (I use fake ficus trees). You might also want to treat the first sidewall reflection points, though with the fairly directional SL-3's this might not be necessary. Once again diffusion is preferable to absorption, unless your room is too bright. And even then, a little absorption goes a long way. The reason of the diffusive treatment of the first reflection points is that strong, distinct early reflections can skew the imaging, but we'd like to preserve that energy to enrich the timbre and spaciousness.

Okay, now let me come at the same issue again, this time focusing more on voice and instrumental timbre than on concert hall-ish acoustics. The tonal balance of the reverberant field has a significant impact on the perceived timbre. The bass of your hybrid SL-3's is essentially omnidirectional, which means there will be lots of reverberant energy in the bass. The panels are much more directional, and so put less energy into the reverberant field, relatively speaking. If we use absorption to soak up the backwave of the panels, there will be a severe shortage of mids and highs in the reverberant sound field. As a result, the speakers will tend to sound precise, but uninvolving and lifeless, and eventually fatiguing. You see, a significant discrepancy between the direct and reverberant fields contributes to listening fatigue, so we want to keep 'em as much alike as possible.

My advice is always free, and worth every penny.

Duke