flat speaker quandary

Nick, Magnepan and Martin-Logan both make some excellent, high value speakers, but there are differences in their sonic signatures. From your comments I suspect that you really would be better off going with one of the newer Magnepan models rather than any of the Martin-Logans. That said, M-Ls don't need as much toe-in as you've indicated and they can benefit from even more distance to the rear wall. You might also want to upgrade your interconnects. I would recommend something like Cardas or Discovery. My final comment is that you have a good size room and if you're driving the M-Ls hard that your amp may be clipping. They are a difficult load.

Nick -

The situation you describe makes perfect sense to me. Briefly, your room's too big for the SL-3's. But please read my explanation as to why this is so, because it isn't obvious at first glance.

The woofers on your Martin Logans approximate a point source, while the panels approximate a line source. And sound propagates differently from the two - under anechoic conditions, sound pressure level falls off by 6 dB for each doubling of distance from a point source, but by only 3 dB for each doubling of distance from a line source. If we match the levels of a true point source and true line source speaker at 1 meter, then measure again at 10 meters distance, the point source speaker will have fallen off by 20 dB but the line source speaker by only 10 dB!

In a real-world room, the reverberant field fills things in somewhat, and the panels aren't tall enough to truly approximate a line source. But I took some measurements in my living room once, using a pair of hybrids (SoundLab Dynastats), and the results were rather interesting:

With a pink noise source, at one meter the woofer was 1 dB louder than the panel; at 3 meters (normal listening distance) the levels were exactly the same; and back at 8 meters (the practical limit in my room) the panel was 4 dB louder than the woofer. So as you can see, the perceived tonal balance will change with listening distance.

The tonal balance also depends on room size, as a larger and/or more acoustically porous room (lots of hallways or doorways) would have given an even greater discrepancy between woofer and panel because the reverberant field would provide less fill-in in the bass region.

So I hope you can see that a hybrid electrostat is even more of a juggling act that it appears at first glance - the relative levels of woofer and panel have to match up for your general room size and listening distance. Some hybrid electrostat manufacturers build a great deal of level adjustability into the speaker, and some build a wide range of models so that you can match the right size model to your room. Martin Logan falls into the latter category.

If you read a lot of consumer comments on Maggies and Martin Logans, you'll find that comments on the tonal balnce of the Maggies are fairly consistent, whereas comments on the tonal balance of the Martins vary much more - one person says they are too bass-heavy, another that they're thin and anemic, and yet another that they're just right. I strongly suspect that the variation in perceived tonal balance of the Martins has more to do with how that particular room interacts with their combination of line source and point source propagation than anything else.

As I recall the crossover on the SL3 is in the 300 Hz ballpark, so adding a subwoofer would still leave a hole in the midbass and lower midrange. But it would still improve the overall tonal balance. My suggestion would be to add two small subs - one for each channel - so you can run them up fairly high without spoiling the imaging. Look for a sub that is smooth and sounds good up into the midbass region, and that can be crossed over fairly high, rather than putting maximum emphasis on bottom-octave extension. What you'd like to do is add a pair of level-adjustable woofers to augment the ones in the SL3's, rather than adding a deep-bass-only subwoofer. I would imagine there are some rather inexpensive subs that would fit this description, though I don't know of any offhand.

Best of luck to you,

Duke

(Just a suggestion) This could be a very expensive pursuit. Before spending too much money, go listen to your ML3's at a dealer who thinks they are set up well in his shop. If they sound like they do at home then it is unlikely any amount of tweaks will help you. Before jumping back to the maggies, go listen to some other systems. You may find something entirely different. I personally went from Magneplanars then to Soundlab (electrostats) and finally to some omnidirectional radiators and am very very happy.

Though I have no useful information regarding your speakers, I thought I'd suggest that I have found cables to be very important with an ART DI/O. Most recently I've used Cardas Lightning 15 coax, Audience AU24 coax, and Audience Conductor coax. Each is an excellent digital cable but the sound one gets is quite different. The Cardas is warm, well balanced, with high frequency detail. The Audience cables, however, add a little magic IMO. The AU24 sounds very natural, has a solid low end, and what I'd call an open sound stage. It has the most audiophile-like sound. The Conductor might be called darker but to me is even more magical with the DI/O bringing out the warmth that I love (at least with my equipment: CAL Delta, ART DI/O, Wright pre, Korneff SE45 amp, Lowther DX3 speakers). Especially given their price, I'd give the Audience Conductor digital cable a try. Don't make a jugement during the first few seconds. Give the music a minute or so to draw you in. (I also like the AU24 speaker cable and have rewired my custom cabinets with Audience hookup wire.)

Nick, I think Audiokinesis and Onhwy61 may have hit on something. Others also hit on a few issues. I own older Maggies and full range stats. I have also heard the SL3 but not in my house. The first time I heard the SL3 was with a Evo power amp. I was impressed. I know the room I heard them in was smaller than yours. The second time I heard the SL3 was at a Tweeter store driven by B&K. It imaged well but I can't imagine any buying them based on what I heard. They were sterile, cold and strident.

Audiokinesis spoke about the drop changes between a point source and a line source. I haven't measured it but he may be right. The ML's don't drop nearly as fast in level as does a point source. I have measured the ML in my room. My room is the same size as yours but I use physically bigger speakers. I use my ML biamped most of the time and adjust the woofer to my listening position. In my room every speaker has to conform to the same listening position. I don't have a lot of seating options. When I switch to my old maggies the listening position is the same but usually the speakers have to be in slightly different positions than the ML. Also my ML's have bigger panels than yours and may be harder to place. My maggies are also bigger than yours and are even harder to place than the ML. it usually takes weeks for me to get the Maggies right.

My basic points are: 1.Your amp could be the issue. ( I don't know the DNA1) 2. The speaker could be too small for the room. 3. To fix this problem could be an Odyssey (no pun intended) and certainly expensive. 4. The speaker could also be showing the weaknesses in your interconnects.