Kitty Kat Port Tuning Progress

After a difficult day at work, and a bit of supper, I decided to spend part of the evening listening and fiddling. I began by powering up the Benchmark DAC1, and the Creek 5350SE integrated amp. It is true that the amp especially needs to be warmed up before it sounds completely correct. I suspect that the bias current of the outputs is not correct until the devices reach operating temperature. After a suitable time, about 30 minutes, things settled down.

I had previously placed the straws back in the Kitty Kat ports, sticking out about 1/4" from the rear of the port. Somewhere between flat and 1/4" outside seemed the best position. I then listened to several of my favorites and some older stuff I hadn't listened to for several years. It then occurred to me that the bass was still not quite right, and so I decided to reposition the speakers, farther away from our audio cabinet, and more in the open. Then I towed them in a bit and made sure the back corner closest to the wall was only about 1" away and the farthest corner more like 4" (on average the 3" target depth). The stereo image was much better with the toe-in.

I was also surprised to hear the sound change as I moved the speakers. The bottom end is much more sensitive to the position of the rear wall, and things to the side of the Kitty Kat cabinets than anything I have ever used before. After setting in this position for a time, I decided that things were better and listened to several test CDs as well as some other recordings.

Some of the conclusions from last night's listening session:

  • The bass is more strongly influenced by the exact positioning of the cabinet that I previously appreciated.

  • With the increased toe-in, the imaging improved a lot

  • The top and mids are still very detailed without being the least bit harsh or strident. This is a welcome and pleasant surprise. I have heard so many studio monitors and audiophile speakers that seek to reveal the last bit of detail but come off as bitingly bright, that these are so much easier to listen to. They have the detail and transparency, without the sizzle. I got a lot more that I thought I was getting in this regard.

  • The bottom octave of the bass is good for about 1/2 of the octave and then drops off too much. A good test for this is one suggested by Bob Katz in his paper on Subwoofer Setup( Here is the .pdf version ). He suggest the use of Rebecca Pidgeon, The Raven, Chesky JD115, available at record stores, high-end stereo stores, or from Chesky Records. This recording has several bass notes that cover the region normally surrounding most subwoofer crossovers points.

    I did some listening to this recording and the first bass note has all the upper harmonics, but the lowest fundamental is definitely softer on the first note than the others. However, the repositioning of the speakers done this evening did improve the situation. I think that further tuning and room positioning may improve it even more. Proper speakers stands may also help.

  • Imaging tests. I played for the first time on the Kitty Kats the Chesky Records Jazz Sampler & Audiophile Test Compact Disc, Vol. 1. This disk has a set of imaging tests which are made on a live stage with a Blumlein Stereo pair of mics. The speakers moves from center to left and right across the soundstage. For most of these tests things sound normal as expected. However, for one test they move to an extreme left and right position, outside of the normal Blumlein pair soundfield. The idea is to see if your system can image beyond the outside edges of the speakers.

    The right side test sounded pretty much as expected, with a lot of out-of-phase material presented but no actual position of the announcer voice. However when he moved to the left side, the situation was completely different. His voice did actually sound like it was coming from outside the left speaker. This was the first time I have personally ever heard this effect in a repeatable way. Perhaps I will be able to get the effect on both sides when room placement is optimized. This was a very encouraging demonstration.

  • My hope increased that eventually, with proper tuning, and the subwoofers, this system may yet yield the hoped for quality.

  • Our Behringer ECM8000 calibrated microphone from Cross-Spectrum arrived today. Very soon we will begin making some actual measurements and publishing the results here.

Please see the next article in the series Kitty Kat Port Tuning Progress II

Copyright © 2010 David L. Bytheway