Four Ways, No Waiting

Four Ways, No Waiting

Written by Bill Leebens

I’d prefer not to dwell too much on the name brands of electronics (of the front end, but sure, as they pertain to the speakers) at this time, but rather concentrate on the room and speaker system that is built around it.

The pre-amp source is a Parasound Halo P-5. This feeds into a vintage Pioneer SF-850 electronic crossover, which is set at 250 and 8k Hz.

The low pass in turn feeds into an Audio Control Richter Scale III, which sets the additional crossover point of 60Hz. In this manner, the mid and hi frequency section are only affected by the Pioneer unit. This is a superb vintage unit, and by far the best that I have tried, with respect to analogue devices. I have no desire to use any sort of dsp at this time.

The subs for both channels can be seen in the corner. Each separate enclosure utilizes a slot-loaded enclosure from 60-250 Hz; the horn-loaded driver runs from 250 Hz to 8 kHz; and the Stage Accompany ribbon tweeter runs above 8 kHz.

For 60Hz and down, the stereo low-pass signal is fed to a pair of Crown K2’s, of which each amplifier channel drives a pair of Acoustic Elegance AE-IB 15’s (8 total) set up in an infinite baffle, manifold mounting, configuration. The I.B. construction was done in a jutted out room corner, reconfigured to provide a structure at a 45 degree angle to the room. The volume behind the drivers is set up by a very large closet, and provides approx 500 cubic feet of air space. The upper quad of 4 receives the right cahhnel, the lower is the left channel. I have experimented with a mono signal, but, to me, it doesn’t make much difference. The wavelength of 60Hz corresponds to the room dimension adjacent, so at this point, and everything lower, it simply fills up the room. Localization is impossible. The room is 19×21 feet. 8 foot ceilings. Additional alcove space for the gear. There is NOTHING between the speakers. NOTHING.

Close-up view of the slot-loaded midbass enclosure.

For 60-250Hz, I built a pair of push-pull, slot load devices(ppsl) each containing  a pair of Eminence Definimax 4012HO. They are sealed enclosures built from double walled mdf+plywood, and in some areas they are triple walled. I sized the enclosure to provide a critically damped Q= .5, and with the very close coupling of the drivers, the Fs dropped from 46 hz, to 40Hz. The resulting mass loading of the drivers also raised their respective Qts, thus, the oversized enclosure compared to what would be required of a stock mounting technique. Bryston 7B mono blocks power the ppsl’s.

For mid-range, covering 250-8k Hz, I mounted a Tang Band W8-1772 in a large round vintage Jensen Peridynamic horn, circa 1941. I modified the horn throat, flange, and body, with copious quantities of damping materiel, and a nice coat of red paint. The back wave of the 1772 feeds into a transmission line, which turned out to be MUCH better sounding than any sort of “open back”. The driving amplifier is a custom built unit, but based on a Harman Kardon Citation 12. This was done by Palm Beach Acoustical Fidelity.

The highs, from 8k Hz & up, are done with the Stage Accompany SA-8535, driven by a custom built tube amp, again, by Palm Beach Acoustical Fidelity.

The vintage Pioneer electronic crossover, with the custom-built tube amp above it.

As might be visible from the pictures, the room is well treated with acoustic damping. Yep, it’s a man-cave like room, and does not have to meet any sort of approval for it’s aesthetic qualities. (No one complains, because, with most audio gatherings, yours truly does some fine b-b-q).

The system is superb sounding and utterly effortless in its dynamic prowess. It culminates 44 years worth of effort. If I may borrow the saying:  It’s not that I have been taken to the venue, but rather, it’s that THEY are here.

[A reminder: we invite readers to submit their systems/rooms to Copper. Details of gear and room treatment are a must, as are CLEAR photos. Just email us, and you may see your room in a future issue! —Ed.]

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