Sonics of Soundlabs

Hi Chris,

I've never owned Soundlabs, but I've been listening to them and A-B'ing them since their inception. I would have bought them too, but never had a space big enough to house them (I think a 20' x 30' room is minimum IMO) so I've been getting along with my ML CLS-IIz's (now with a Depth SW) for 15 years. I agree with your analysis of Maggies. There are some things they do very well (low level is not one of them!) and I even gave a pair of Tympany 1-D's I had stored to a friend for a house-warming gift a couple years ago.

If you have the space for the Soundlabs, go for it. But before you do (and if you liked the Prodigy) definitely don't make a decision until you've auditioned the new ML Summits. I thought they were stunning when I heard them at CES -- and they're not space hogs! They also have their own built-in amp for the low end, so you can do a 150W tube amp for the panel if you want.

Chris,

If you put SL's in a 15x21 room, you'll have to put them on the long wall to avoid the large sidewall reflections they'll produce (which is why you need a large room!) and so that means you'll be listening to them (relatively) nearfield -- which is a shame with speakers that are truly capable of producing a huge soundstage-and-sweetspot in a large room.

I'm stunned you were unimpressed with the Summits! Something must have been terribly wrong with the demo. I can only assume poor setup and mediocre associated equipment. Do it again somewhere else. Their panels have the same output as the Prodigy with a panel half as big (better dispersion and imaging) and the low end is just about the best I've heard -- in both response and matching to the panel.

The laws of physics are immutable (except for quantum physics which we'll leave aside for now). At sea level, at 68 deg. F., sound travels at 1127 ft/sec.

So the length of a 20 cycle/sec sound wave at sea level at 68 deg. F. in free air is 1127 divided by 20, or ~56 feet (that's for a full sine wave.) To realize the full intensity of this wave in an enclosed room, as produced by the speaker, the room must have at least one dimension equal to or greater than half that length (28 feet). This can be measured from a top corner (at the ceiling) to a diagonally opposite bottom corner (at the floor.)

If that criteria is not met, then the wave cannot develop fully, and although you will still hear the 20 cycle sound, it will require more and more bass boost (as the room gets smaller and smaller) in order to realize a flat room response (assuming the speaker is producing a flat frequencey response)

No amount of "treatment" can increase the physical size of a room. Judiciously placed absorption and traps can only kill unwanted reflections which compromise the soundstage image (particularly sidewall reflections). If you kill all the reflections (as in an anechoic room) then you are listening to the loudspeakers' direct frontal output (100% nearfield) just as if they were a pair of great big headphones.

These principles apply to all loudspeakers, not just Soundlabs. However most loudspeakers can't match both the output and frequency range of products like Soundlabs, Wilsons, etc. etc.

If you're going to buy a pair of speakers that can do what Soundlabs can do, then you owe it to both yourself, and the speakers, to provide them with an environment that allows them to "be all they can be," meaning to fully "breathe" in all directions. The optimum size (i.e. the opposite of an anecohic room) would be one in which the larger dimension was somewhere around that of a full 20 cycle wave, say 30x50 feet. Some people have even suggested that outside would be best, but that is incorrect. Outdoors, the sound just goes off in all directions and never comes back -- the same as in an anechoic room; and in both cases, the effect would be one of listening to giant headphones!

Atmasphere -- I believe I did mention that in my post :~)

These principles apply to all loudspeakers, not just Soundlabs. However most loudspeakers can't match both the output and frequency range of products like Soundlabs, Wilsons, etc. etc.

Mcreyn -- you are incorrect. When a half wavelength (~ 28 ft for a 20 cycle/sec tone) is longer than the longest dimension of the room, it cannot fully form in space before hitting a wall and reflecting. causing it to double back on itself, producing points of both cancellation and reinforcement. If you happen to be at one of the reinforcing points, it may appear that the bass is very loud, but just a few feet away there may be a null point with very little bass due to cancellation. Right at a wall surface, there is always louder bass because that's where the wave changes direction, therefore releasing a lot of energy when it momentarily stops before being reflected in the opposite direction. That phenomena happens in all rooms though, regardless of size.

If your analysis was correct, then shorter organ pipes would produce lower notes :~)

,

Mcreyn -- standing waves are only produced when a room dimension is a whole multiple (not a fraction) of the half wavelength of the frequency in question. The room will gain in dB (more SPL than the speaker is putting out) by resonating at the frequency in question (like an organ pipe) and that is why bigger rooms have lower resonant frequencies (per Mr. Noussaine's remarks)

Once again, a room smaller than a certain frequency's half wavelength cannot resonate at that frequency and thus the SPL cannot increase over what the speaker is putting out by itself.

I also read Mr. Noussain's remarks on avht. The smallest room he mentions (assuming an 8 foot ceiling) is quite big enough to develop a full 20 cycle wave (roughly 13x20), and so standing waves (and room gain) are definitely possible at that frequency -- however, in a room too small for the 20 cycle wave to form in the air, standing waves, and therefore room gain are not possible.

As for his weird experience with the Velodyne: A loudspeaker will always put out the same SPL (at a given frequency, at a given power input, at a given distance away from it) in any environment (or even outdoors) at normal atmospheric pressure UNLESS there is either cancellation or reinforcement at the point where the measurement is being taken (which is probably what happened to Mr. Noussaine, and he just didn't realize it.)

I had trouble visualizing how he placed a speaker "identically" in two rooms of different size -- so I'm not sure what the heck he meant; maybe he meant "proportionately" since "identically" would be geometrically impossible. It sounds like he once again stumbled onto a null point without realizing it.

In any case, I would not be especially drawn to his remarks in the future.

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Chris, the longest diagonal of your room is 28 feet (thanks to the 11 foot ceiling height!) and so flat response down to 20 cycles is possible. I think some of the other posts (regarding the phenomenon of "room gain" in smaller rooms) failed to take into account that the speaker you are considering has what Prof. Linkwitz calls a "dipole woofer" which, as he makes very clear on his website, requires the necessary 1/2 wavelength dimension (or more) to produce a given frequency:

Room modes cannot exist when 1/2 of a sound wavelength exceeds the longest room dimension. If this is 7.5 m (24.6 ft), then a wavelength will be 15 m and the lowest mode frequency is 343 m/s / 15 m = 23 Hz. Below this frequency bass response may increase due to room gain, if the woofer is a monopole. For a dipole woofer the response may stay flat or drop off, depending on the rigidity of room surfaces and lack of any openings.

If your listening room were just a little bit smaller, you would definitely be better off with a hybrid speaker (like the Summit) which have monopole woofers which allow the development of "room gain" thus maintaining SPL at lower frequencies in small spaces. Just remember that "room gain" (or "transfer gain as it is sometimes called) is only an important factor when the room is too small to allow formation of the 1/2 wavelength of a given frequency (an automobile interior is probably the extreme case.) At that point, you are no longer in a "listening room" but instead you are in a "secondary speaker enclosure." And if you push that example even further, in other words, reduce the size of the listening room down to zero, you are wearing headphones!

Chris,

You might want to take a look at diamonds system, and possibly contact him:

http://forum.audiogon.com/cgi-bin/fr.pl?vopin&1107813475&read&3&4&5

He thinks his new Summits are awsome.