Cheap and temporary Cornwall tweaks

Following the advice of J.W. Gorman off the Klipsch BBS, I tweaked the horns in my old Cornwalls (serial numbers 32x57 and 32x58). The tweaks are temporary, simple, easy, low-cost and extremely effective. It does indeed stop the harsh ringing and jitter of the mid-range and high-end horns.

Last night I reversed the roles we normally hold, my speakers and I. Instead of my worshipful genuflection before their presence, I gingerly placed the 100 pound babies face down on the floor, and removed their backs.

Inside I found the cabinet walls trimmed with thin, light gray, padding wall to wall. The padding was edged and tied down with a framework of delicate string. It looked like a miniature 1890s padded asylum cell for some insane small creature.

The K-33-E woofer was surprisingly light, more like a Radio Shack woofer: No large frame or huge magnet. In fact, the magnet was as thin as the padding.

The K-51-V metal mid-range horn was more impressive. It rose almost a foot high and was topped by a rounded magnet. The K-77-M tweeter by comparison was much smaller than it looks from the outside: No bigger than the yellowing coils on the B-2 crossover board.

Like a pottery artist dabbing bits of clay on a masterpiece I packed a layer of caulking cord over the pyramid shaped sides of the throat portion of both horns. Once impressive black horns, they now looked like old gray mummies. Padded straight jacket inmates, tall and tiny, in a miniature padded asylum cell.

The caulking cord is gray weather stripping window putty sold at Home Depot for less than $5.00 in 30 and 90 linear feet rolls. I used 120 feet. It comes in 1 1/2" wide flat strips easily torn and pasted by hand. Each speaker took about one network TV hour-long show.

Next, I placed washers underneath the crossover boards. The washers were the thickest I could find in the plumbing section and cost $.47 a piece. Finally I gave the speakers their annual rub down with lemon oil like the fine through bred race horses that they are.

The effect of the tweaks was immediate and wonderful. The clamor and ringing was gone from the high end.

I immediately played the last CD I was listening to in order to hear the contrasts and the tone. Michael Frank's Blue Pacific CD sounded soft, gentle and warm. My wife even commented on how much she liked it; but even more important, she did not ask me to turn it down from 8:00 on my pre-amp dial, which she normally does.

Before the tweaks, I played Sprinstein's Born to Run CD with a feeling of harshness, even though I wanted to blast out the music, I had to keep turning down the volume. The high end was hard and harsh - I blamed the age of the recording.

But when I played Springstein after the tweaks, it was with out pain at 8:00 on my pre-amp dial. Then I played a Nimbus Natural sound CD with a Chopin horn section to see if the trumpet sound was still good. It was.

The jury is back: The verdict is in. The only thing remaining is the penalty stage. These tweaks are great! Makes me wonder if I needed to move to the Rotel CD or even the Dynaco tubed pre-amp years ago.

The best part is that I can reverse all or any part of these tweaks easily - simply remove the layer of gray putty and the black washers. And in fact, I may remove the layer on the tweeters to allow some ringing to augment the sizzle of cymbals, if several hours of listening to a variety of music warrant such a move.

The tweaks are simple, easy, low-cost and extremely effective. It does indeed stop the harsh ringing and jitter of the mid-range and high-end horns. The high-end speaker still tweets, but the mid-range horn no longer squawks.

Strongly recommended: Thank you J.W. Gorman!

After reading several Bruce Edgar articles in Speaker Builder and an interview in Sound Practices I wondered if I could fit my previously reviewed (Jan. 97) Cornwalls with tractrix horns. I contacted Klipsch Pro who have a 600 hz 1" throat tractrix horn available for $50 per horn. The horns fit right to the Cornwall's Alnico magneted mid drivers, but the horn's mouth is much larger so the hole in the cabinet had to be enlarged; at the same time I mounted the T-35 tweeter to the outside of the cabinet, it no longer fires through a 3/4" deep "tunnel". The results are very good; the sound is smoother with no trace of "horn sound", vocals are even more solid and imaging and high-end clarity are improved. I recommend this very cheap mod to all owners of Cornwalls or Hereseys, it's most worthwhile.