Saturday my wife and I were in the Portland area to visit RM 40 (FST, TRT, AP wire) owner John D-M (soundguy3).
His listening room was large, with a sloping ceiling left to right reaching up about 14 feet at max. The only damping were some fiberglass vertical blinds. Equipment was on the floor between the speakers which had been placed (at John Casler's good advice) 10ft out from the back wall, which was brick fireplace plus glass. Toe in was pretty much crossfired at the listener's head, and I found little reason to change it: in the end we rotated one speaker 1/4" more towards the center.
Equipment included EAR pre and power amp, and audiophile CD source. Wire was AP copper 12 gauge, some Monster Cable, and some Jena. We checked AC polarity for maximum clarity.
While the owner was satisfied with the sound (approx 11 o'clock on all controls), I found it too smooth and rolled off, with an 80Hz bass dump and lacking a first octave. Singers lacked chest voice, organ its pedals. The overall presentation was very nice, however.
Within an hour of starting the tuning process we hit a snag: the now tuned speakers, bass hump eliminated, had a hard edge, and climaxes were congested and distorted. I started thinking dark thoughts about the "digital" power amp which I had never heard before. John was fond of it so there was no question about swapping it out for the Mac tubes or the Aragon 4004 on hand.
First remedy for the hard edge was to switch from AP copper speaker wire to Monster Cable, which was much smoother but lacked detail. Considerable tuning restored the trebles and clarity of the AP and gave us good bass extension without the great bass control of the AP. However, climaxes were still congested and I was really puzzled. The RM 40 is a very low distortion system and the kind of distortion were we getting in the tuttis was unfamiliar, not clipping but not clean. John then remembered he had an old pair of Roomtunes (15"W x 4'ft tall) in a closet unusued for 15 years. After placement experimentation these ended up in the far corners behind the speakers. We also removed some clutter including the fireplace set and a fan. With these changes the sound was excellent, with little edge.
Since John is a well-established opera singer (Metropolitan Opera since 1993) we could do a unique "live vs recorded" of his voice from commercial performances he had done in 1987 and 1998. It was amazing to hear his recorded voice and then have him start singing along with his own music, a unique front-to-back stereo. We settled on the sextet concluding the first act of "L'Italiana" in which John, five soloists and the chorus have prominent parts. The fidelity of the recorded voice improved with further adjustments (very small level control adjustments of about 1/20dB, plus 1/100g bits of putty) until we could hear the conductor quietly turning the pages of his score! We heard the same ensemble at least five times without the treble edge but still suffering from the aforementioned congestion which was now a complete puzzlement to me.
John was so into the process, now 7 hours along, that he would occasionally cut loose with his full voice, 2 ft behind my head. Believe me, that's a sound I'll never forget! I should mention that John, now in his early 50's, has become a master with full control over his silky, evenly produced and rich-toned voice, including all the dynamics and shadings Rossini must have wanted from his basso (John has the low E but only at reduced volume, a consequence of age. Weight loss and control of asthma has improved his singing immeasurably; his younger self can no longer keep up).
After 8 hours it appeared to me we do not improve matters, although the distortion on the big ensembles remained. With the Monster Cable in place things were very pleasant, and a quick switch back to the AP produced a tremendous blare which nobody wanted.
As we were about to leave, John went back to his equipment and noticed that the power amp was switched to "balanced" input although we were using RCA's. In other words we had been listening the entire time with half a signal driving the amp. Switching back to unbalanced removed the problem as well as remnants of the treble edge and all of the congestion. We were all happy at this point.
Moral of the story: if you have an undamped room even a small amount of foam or fiberglass can do wonders. Plus, it is easy to be completely done in by a hard-to-find problem with your equipment.
This was a uniquely enjoyable and satisfying setup, even if it did go down to the last minute. At the end I felt that the system performed close enough to the sound of live music (remember, I had that as a reference almost the entire time) as to make any shortcomings unimportant. John now has a listening tool, a companion, and reproduced sound that can handle anything (we played over a dozen CD's of varying kind from Muddy Waters to Patricia Barber to Barber of Seville) and handle it with utter aplomb.
My wife and I travel in November to NYC to hear John's Bartolo (Rossini) at the Met, and we can hardly wait.
