OTHER SYSTEMS

A few more systems that we, my friend Jerry and I, had developed over a 4 year period, or was it 5? At any rate, it took 2 years just to get the little guy right and the larger version didn't work out as easily as one would think. The satellite system was an ongoing project during the development of each of the previous two, with several months of tweaking after the others were completed. I'll save the details for the corresponding pages. Don't wanna scare ya away.

This one is the 'little guy', not that it's small but because it's the smallest of the three. It's about 38 inches tall and 11.5 inches wide and weighs about 70 pounds.

This photo was taken in a park in Phoenix. We had to carry this thing up a narrow rocky desert trail for about a quarter of a mile without dropping it. I sighed in relief after we got it up there but was reminded that we still had to get it down. .. :(

This little fella (above) was 2 years in development. Construction is of 3/4 in. MDF and internally braced. The woofer diaphragm is polypropylene and the midrange and tweeter are Kevlar®. The tweeter was later replaced with a similar unit with an oxide coated titanium diaphragm which resulted in crossover modifications. The midrange is loaded with a cylindrical chamber as the original rectangular chamber produced nasty peaks at frequencies which corresponded to multiples of the chamber's internal dimensions. This was noticed by my partner, Jerry, with his golden ears and the LMS corroborated his aural discovery. The slanted front, although aesthetically appealing, is actuall functional. An earlier design of mine with a vertical front had almost similar sonic qualities but the stereophonic image was badly smeared. Although improvements in the crossover design improved this, the slanting of the front baffle locked it in. The angle is such that the voice coils of the midrange and tweeter are in the same vertical plane and that of the woofer is within 1/2 inch, which is negligible at the crossover frequency of 300 Hz., roughly 45 inches. With horn speakers ignoring this issue and still sounding grreat, then far be it for me to say otherwise. As for our speakers, we most certainly claim benefit for the time aligning of the drivers.

Sensitivity is a modest 87 dB 1w1m over the passband; -3dB @ 35 Hz to beyond 20kHz - outdoors and 28 feet away from the nearest reflecting wall; the closest I have to anechoic conditions. Jerry & I are kinda pleased with this system especially after an AB comparison against a similar system priced at about $2700 at a local high end shop. Much to our surprise, these were preferred due to their sonic quality and imaging characteristics.

The unit on the left is the larger version of the little fella above. The squawker and tweeter in both systems are identical as are the crossover frequencies.

This one on the right is part of a satellite system. The dual 12 inch woofer enclosure can barely be seen on the far right. The 2 woofers are independently filtered so as to form 2 three way systems. The low pass filter is third order at 125 Hz.The squawkers are vented and the lower half of the tower is filled with 70 pounds of sand to provide stability as, without the sand, the unit was quite top heavy.

The system on the left is a larger version of the "little fella" or "little guy" mentioned previously. The woofer is a 10 inch version of the 8 and gives a little more "oomph" in the lower register. Other than that and the larger enclosure, the rest of the system is the same. The second order crossover frequencies in both systems are 300 Hz. & 4000 Hz. One would expect that it would sound the same with more bottom end "oomph" but the imaging was smeared. After a myriad of theories and attempts at getting it right, Jerry again came to the rescue - with his golden ears. After a few weeks tweaking the crossover; he did it. Still not quite up to the imaging quality of it's little brother, that slight deficiency is overlooked by the added "oomph". Perhaps the larger panels aren't damped enough despite the internal bracing or maybe it's the wider front baffle which surely has an adverse effect on that phenomenon known as diffraction. Mr. Klipsch once said, "The best tweeter, by far, is in the open." Perhaps the same applies to the midrange, or squawker, as Mr. Klipsch would call it.

The tall fella on the right is my "piece de resistance". The use of the personal pronoun in the singular is due to the fact that the 8's still image better according to Jerry and I'm not going to disagree with him. However, the d'Appolito configuration sure gets one's aural attention, as these things approach the sound of a well designed horn. The theory behind our using this configuration was the fact that 2 diaphragms would have to move half the distance to get the same sound pressure level, hence less modulation distortion and cleaner sound. This is characteristic of horns due to their high efficiency. These things are clear even at sound pressure levels as high as 100 dB. The prototypes of these are still used by me in my music room, the Chamber of Horrors, and anyone, so far, who has heard them, despite their appearance, is awestruck.