The most placement forgiving planar speaker?

Hi DrKen,

Albert was right on the money about the Soundlabs. I had the pleasure of hearing them in his house twice and they imaged amazingly well.

If you can't afford their price tag, however, I would go for the Martin Logans. Their curved pannels seem to help quite a bit with placement. You still need a couple of feet of room from the back wall but the side walls are not as problematic. The focus and image size are very good but the venetian-blind effect is still there, albeit not quite as severe as with the Eminent Technology and Maggies, which I also like. I prefer the Martin Logans because they are quicker and airier. ML also excells in customer service, which should not be overlooked.

Soundlabs are excellent speakers. U-1s, A-1s, and M-1s are all among the most impressive speakers available - if you have the right equipment, and if you have a proper room.

I've heard at least seven pair of Soundlabs: 3 pair of U-1s, 2 pair of A-1s, a pair of M-2s, and a pair of Pristine IIIs. One pair of U-1s sounded exquisite, most of the rest sounded very good, and one pair sounded very so-so. I don't think the difference was so much attributable to the models (although, no doubt the U-1s are the best of the best), or even the electronics (although the gear, especially the amps used with Soundlabs will make a significant impact). What I believe caused the considerable differences I heard among the seven pair was the variation in room acoustics.

At the end of the day, the low end that you can get from Soundlabs, or any other planar, or any speaker of any design will to a degree be determined by the length of your room. For example, I think a 32 Hz signal has a wavelength of approximately 35 feet. That means that if you are trying to accurately reproduce a 32 Hz signal, your speakers need to be at least 35 feet from the back wall (behind the listener) and you will need some additional space between speakers and the front wall (behind the speakers). With less than that total distance, the primary wave is going to reflect off the back wall before it has fully "unfolded" it's fundamental wave and you are going to have less than an ideal result. How much less than ideal is going to be a function of several considerations, only one of which is the length of the room. Once you establish the room length needed to support your desired lowest frequency (assuming the speaker can go that low - pretty much all models of Soundlabs will go to 32Hz), the room length will in turn dictate an optimum room width and ceiling height. (While there is some debate about whether Cardas' formula yields the exactly optimum "golden ratio" it appears that most of the other ratios put forward as "golden" are substantially similar to the ratio recommended by Cardas; ie, the relationships between room length, width, and height are widely accepted as being important to achieving good acoustics.) Additionally, the ideal room will not be rectangular in shape, but will have pied out walls and a pied ceiling (all of which starts to resemble the shape of a concert hall). Finally, the room treatments need to be implemented so that reflections and absorptions occur at the appropriate locations. The chances of all this lining up in a room that wasn't designed for audio is slim, and therefore what virtually all audiophiles get is something that is less than optimum. How much less than optimum is generally unknown until you experience the environment (ie, hear the speakers and the rest of the system in the particular room). It may be that a given room happens to yield acceptable results, or that in moving up from a lesser set of speakers to say, Soundlabs, that the improvement is enough to meet your expectations. But I'd be careful about saying that any speaker is notably less sensitive to room acoustics than any other speaker because all speakers interact with the room to form a "system" that impacts the overall sound.

I know that the readers on this thread probably know all this stuff, but I can tell you that once you invest several thousand dollars in a pair of fairly esoteric (expensive, large, heavy, hard to pack and hard to ship) speakers you won't want to find out that what generally might have worked for someone else doesn't work so well in your room. It's my opinion that when you reach a certain level of equipment that attributes such as frequency extension (at the bottom and top), frequency response/tonal balance, defintion/detail, and imaging are all going to be impacted as much or more by the room as they will be by the equipment.

Again, I think Soundlabs are among the all-time great speakers, but I know from experience that you can't just stick them in any room and expect them to do their magic. As much as I admire Soundlabs, I can't see any big technical reasons (other than perhaps their dispersion characteristics) that would make them easier to place in a room than other planars. And even with respect to dispersion, I think all you can say is that Soundlabs have a different/unique dispersion ability, but again, whether that ability works well in any given room is a function of the room's characteristics and how those characteristics work with the speakers – it’s not just a function of the speakers.

In summary, I think it's wise to proceed with caution on generalizations. With so many interdependent variables I think the results are as likely to be random as they are predictable. Having said all that, I’ll go way out on a limb and say this – if I had a free pass on just one of the variables, I think it would be room length; having a longer room (well over 20 feet and preferably closer to 40 feet, or even longer) would likely give the low end a chance to do it’s magic, and in turn get out of the way of the exquisite midrange and high end that Soundlabs can reproduce. Additionally, given that most folks building rooms in houses have some sense of proportions, any room that is 40 feet long is likely to have some decent width and probably ceiling height – although the chances of the ratio being golden is slim (obviously a 40 foot hallway isn't going to do the trick). To be sure, this "longer is better" notion is just a consideration and is itself random and far from quantifiably optimum, but I think the beauty of Agon is that people are helping other people learn from their experience and as a result hopefully more people are getting a reasonable return on their (money, time, and effort) investments. With that as a caveat, my very rough rule of thumb is that under 20 feet in length, you are pushing your luck, at 20-30 feet you stand a chance, over 30 feet you’re getting warm, and by 40 feet you might be hot. And if you really want to get it right, study, measure and try to create the ideal room environment, or try to get a demo in your room first (good luck with that :).

Ken, you don't mention any budget range in your question regarding the placement of planar speakers being difficult regarding room placement. The reason I'm bringing this up is because I think MG-3.6s are great speakers and are very competitive with the much more expensive Sound Lab speakers. There about $3000,00 less than the Sound Labs,and in my opinion, give nothing up sonicly to the Sound labs. If you go a step higher price wise then your talking about one of the all time great speakers a MG-20.1 at $12000.00. Either speaker would be a fine chose if you have enough room for placement. I have found as long as you can get about 3 to 4 feet off the back wall and at least 2 to 3 feet off the side walls and can sit back off the speakers about 8 to 12 feet the Maggies work just fine in most rooms. You can also experiment putting the ribbon tweeters on the inside or outside to decide which gives the best or most appealing combination of soundstage width and depth along with details inside the soundstage. The Sound Labs and the Maggies are both great speakers, I don't believe one is superior to the other, I have listened extensively to both, but believe that 3.6s are truly one of the great bargains in world reference speakers. Hope this helps.

Sound Labs are indeed the most forgiving planar speaker of room placement due to their curved design. However I wanted to mention that getting bass out of them as a lot more to do with amplifier choice then room placement (as long as a few simple rules are followed with respect to the room). IOW, if you put the wrong amp on Sound Labs, no amount of room placement will help you.

You have to use a tube amp for starters. Sound Labs want an amp that can make constant power with respect to load impedance and this is something that the vast majority of transistor amps cannot do.

Hi Hifi brings up some points that I'd like to comment on. He's right about the radiation pattern of the Sound Labs contributing to their relatively friendly room interaction, but I'd like to explore some of the reasons for this.

The radiation pattern of the Sound Labs is exceptionally uniform over a wide arc, either a 60, 75, or 90 degree arc (depending on the model). Now note that a dipole has a figure-8 radiation pattern in the bass region. As we go up in frequency and the panel's characteristics begin to take over, that figure-8 pattern is maintained all the way up the spectrum (especially in the case of the 90-degree pattern full size models). The result is not only an exceptionally wide, uniform sweet spot, but also a tonally correct reverberant field. This is extremely rare in loudspeakers, but is common among live instruments - and is one of the reasons live instruments sound better and more relaxing than virtually all loudspeakers.

Hi Hifi commented on the importance of a large room. Well, that isn't as critical with the Sound Labs as you might think. First of all, you don't need a large room to generate deep bass. Think of a high quality car stereo system, or as an extreme example headphones. The ears register pressure even if the room dimensions are too short to support a wavelength.

Now with a speaker whose reverberant field response is tonally incorrect, the more "room sound" you get the worse the tonal balance. But what if the reverberant sound isn't detrimental to the tonal balance? In that case, the size of the room is much less important.

Note that a piano sounds like a real piano in pretty much any room. And note that, in your living room, a concert grand piano will sound better than a little upright piano - even if ideally the concert grand piano should be used in a much larger recital hall. Well, the same principles apply to loudspeakers that get the reverbrant field right.

Sound Labs can be positioned quite close to the back wall, moreso than most planars. There are two reasons for this: The first is, they have plenty of bass to begin with, whereas most planars are barely ekeing out adequate bass so when the nearby back wall reinforces the out-of-phase backwave the bass response becomes too weak. Second, that faceted-curved panel has a focal point about two feet behind the diaphragm. This means that you can very effectively treat the backwave (either with diffusion or absorption) by treating that focal point. Actually, it's a vertical line running the height of the panel. The Sallie backwave absorber is one example of such treatment. I've heard Sound Labs sound wonderful with the back of the speaker's base only out a foot out from the wall.

I maintain that the radiation pattern of the Sound Labs is not just "different/unique", but rather that it has significant audible advantages over non-uniform radiation patterns (which covers just about everything else out there). And in particlar, I maintain that these advantages make it easier to get the Sound Labs to sound good in a wide variety of rooms.

In addition to the characteristics mentioned above, here's another benefit of the Sound Labs' radiation pattern: With most speakers, as you vary the toe-in your not only varying the relative amount of early sidewall reflections, you're also varying the tonal balance because it changes depending on whether or not you are "on-axis". The uniformity of the Sound Labs means you can vary the room interaction independent of the tonal balance! Now, the wide pattern does mean that, in most cases, you'll have significant early sidewall interaction. But that can be relatively easily addressed - I use a couple of fake ficus trees.

Regarding Teajay's post, let me say that I've had Maggie 3.6's side-by-side with Sound Labs, and while I agree that the 3.6 is an outstanding speaker in its price range, the big Sound Labs do some things audibly better. Of course the larger size helps the bottom end, but in particular the low-level detail and articulation on the Sound Labs was better. I kept wanting to turn up the volume on the Maggies to hear the details that were readily apparent on the Sound Labs. That being said, if I had the opportunity to become a Maggie dealer I would do so in a heartbeat - I think the 3.6 and below are very competitive in their price ranges.

Duke