Sota Big Monitors..

Not sure what your definition of "big monitors" encompasses. If "monitor" means "sits on a stand", and "big" means "BIG", then...

I hope you don't mind a dealer chiming in about something he owns and sells, but you might consider the GedLee Summas. They disappear as the apparent sound source - no distracting resonances, diffraction, colorations, or response peaks to tip you off. The bass doesn't extend down extremely deep (probably ballpark 35 Hz in-room), so your plan to add subwoofers would work well. Your 40-watt amp would never break a sweat driving them.

As of this posting, the price on the Summa is in the five grand ballpark. I know you're prepared to spend more, but if you can live with the Summa's size and unorthodox, form-follows-function cosmetics, I don't think you'll find their sonic equivalent below ten grand.

As far as state-of-the-art goes, the Summas were designed by Dr. Earl Geddes, the world's foremost authority on waveguide design and a consultant to numerous leading manufacturers. The Summas use a very high quality 15" prosound woofer crossed over at about 950 Hz to a very high quality compression driver mounted on a 90 degree constant-directivity oblate spheroid waveguide. The crossover point was chosen to match the radiation pattern of the woofer with that of the waveguide. The waveguide features a patent-pending refractive index (or foam plug) which eliminates a type of distortion common to horns known as "higher order modes". Briefly, sound that bounces side-to-side down the mouth of a horn is undesirable, and the foam selectively attenuates those sound waves more than the "good" sound that makes only one straight pass through the foam. The crossover corrects the frequency response taking into account the presence of the foam. I think it's safe to say that the GedLee Summa is at the forefront of advanced acoustic design.

Dr. Earl Geddes and Dr. Lidia Lee, the principals of GedLee, have conducted extensive ground-breaking research into psychoacoustics and audibility of distortion. The commonly-used yardsticks of distortion measurement do not correlate very well at all with our perceptions, and therefore are not very useful. Our distortion perception has tolerances and intolerances (thresholds) that are decidedly non-intuitive. In the design of the Summas, Dr. Geddes has focused on minimizing those distortions that are most audibly significant - many of which other designs make little or no attempt to minimize. Even DSP (digital signal processing) cannot solve those problems that require an acoustic solution, such as diffraction and the above-mentioned higher order modes.

I have had several people comment that the GedLees don't sound like speakers, that you can't hear the crossover, that they don't sound like horns, that their depth of image is outstanding, and so forth. Once in a blind test, one of the partcipants thought we were listening to electrostats. I also sell full-range electrostats that this person was quite familiar with, so that's a pretty high compliment for a "horn speaker". Ahem, "waveguide".

Feel free to hit me with any questions you may have about the design of the Summas, or you can check out GedLee's website at http://www.gedlee.com/

Best regards,

Duke LeJeune
AudioKinesis

Hi Ben,

Thanks for your kind words.

Okay, the term "small room" as used by Earl Geddes would apply to your room. You see, virtually all studies of acoustics are of "large" rooms - i.e. auditoriums and concert halls. Very few acoustic studies have been done on room sizes likely to be found in a home (one reason is funding). In auditoriums and concert halls, the problems of echo and speech intelligibility are very different from the problems of imaging and tonal balance that we encounter in our home listening rooms.

The larger the room (and/or the farther away you sit from the speakers), the more the "power response" (summed omnidirectional response) dominates the tonal balance. Very close to the loudspeakers (typically less than 6 feet) the direct sound delivers more sound power to your ears than the reverberant sound does, and this is termed "near field listening". As you move farther away (into the "far field"), the reverberant sound delivers progressively more and more of the energy that arrives at your ears, and therefore dominates the tonal balance more and more. So in a large room, uniform power response is a lot more important. This is of course one of the things the Summas do very well.

Time for a flashback. Many years ago as a pround young amateur speaker builder, I confidently volunteered to bring my big home speakers, nicknamed the "Gorillas", for a dance being held in a small gymnasium. The Gorillas were ballpark 93 dB efficient and sported two 15" woofers, a 7" midrange, and a 1" dome on top. They sounded great in my modest-sized listening room, so they ought to sound killer in a really big space, right?? Well, they sounded awful at the dance. I was crushed, devastated, my speaker-building ego bruised and broken almost beyond repair.

I now realize that in the gymnasium the power response was what we were listening to, and the Gorillas had a roller-coaster power response which followed the narrowing and blooming of the radiation pattern up and down the spectrum. Okay this is an extreme example, but the general idea is applicable to home listening rooms, particularly those on the larger side like yours. The greater the relative contribution of the reverberant sound, the more important it is to get it right.

Hope this helps!

Duke