Fine Tunes #34
Here's an erudite, well-written pensée from Dale Kleve (firstname.lastname@example.org) on two interesting audio points. I'll have to look into the first one, but the second describes almost perfectly our own near-rear-wall listening position and its sweet spot:
"First, I would like to thank you for all the sage advice in helping me tweak my setup. I get so much pleasure and musical information these days. The quest continues.
"About a year and a half ago I purchased a DVD player. Of course, its first purpose was video, but as I'm no vidiot, audio was my chief motivation. After setting it up and watching and listening to a video, I was pleased but soon bored. So I thought to see what the player might do with a CD. I'd just purchased a few and been very disappointed with the sonics on my regular CD player—the music seemed so lifeless. I played those CDs on the DVD machine, and behold, a sonic miracle occurred! The music opened up from its sonic fog and jumped to life. When one's attention is arrested and unwilling to stop the performance, that's good news! Excited, I put on several more CDs that suffered from the same sonic miasma. All were magically transformed. I was so excited I disconnected my CD player, thinking it obsolete.
"Finally, I had time for a long listening session, and was anxious to play on this new miracle player all my favorite CDs—the recordings capable of transporting me to Nirvana. About midway through the second performance, I realized I wasn't having any fun. On the new DVD player, the discs that worked sonically with the CD player were rendered sonically unacceptable, the imaging smeared. It was time to wire the CDP back into my system!
"What's going on here? There seem to be two different ways of cutting bits onto discs. [The discs from] some companies, like Naxos, always sounded best on the CD player, without exception. Others, like DG, Decca, and EMI—the largest percentage, in fact—sounded best on the CD player. But those sounding congested via the CD player always jumped to life on the DVD player! Try Tchaikovsky's Complete Symphonies (Pletnov/DG), Mendelssohn's Symphony 3 (Dohnányi/Decca), and Mozart's Piano Sonatas (Barenboim/EMI).
"My setup has both CD and DVD running through the same Musical Fidelity X-24K DAC, so the only variable is the transport playing the discs. Because of the typical results, I always play a new CD on the CD player first. With experience, I've become good at recognizing bad sound, then 'tweaking' the offending disc by dropping it into the DVD player and finding relief. With new and unfamiliar music, it sometimes takes a little back-and-forth listening to choose the best player, but I've never found a disc to sound equally good on both players.
"Related to this phenomenon, I believe, is the necessity to oversample the digital bitstream to the highest sampling rate. The 24-bit/96kHz technology has rendered even the earliest CDs—obviously engineered with only 16-bit technology in mind—acceptably listenable. One can get to the performance of the music. So those who haven't taken this necessary step or 'tweak' will have much to grouse about.
"Another observation is that different recordings project high-frequency content into the room differently. My theory suggests this is due to the infinite variables of microphone placement and equalization. So I settled on placing the speakers halfway into the room and setting the toe-in to converge at the pressure point at the back wall, behind my head. Now if I sit there and move my head back and forth, I can distinguish the waves of the high-frequency patterns as they 'stand' in the room. As I say, I've found these patterns to vary from recording to recording. In fact, the optimal position may either be in the pressure part or the null part of the wave.
"After much experimentation, I've concluded that the null is more serene in its presentation of the sonic image. The standing-wave 'peak' pressure points take on a slightly hooty and sometimes congested sound. If, while moving my head, I find that the waves are close together, I simply 'look' for a wider null band closer to the speakers. The widest band is the sweet spot for that recording.
"This sound is most analogous to headphone listening. There's no congestion, and the dynamics seem to expand and contract effortlessly. If I get too close to the speakers, the sensation is that the best sound is happening behind me! If I move too far back, the sense of congestion increases. But right in what I call the 'null band,' I find I can be transported back into the hall at the place of the microphones. LPs generally don't project as far into the room as CDs, by the way. But there's a great variety of projection within both formats.
"Another benefit of finding the sweet spot is being able to tune the equalization of the recording for the most pleasing presentation of the high frequencies without resorting to tone controls. If a recording is overly bright, move closer to the speakers so as to be off-axis to the tweeters. It's surprising how pleasing some of these recordings can sound; don't be afraid to move closer to the speakers!
"So get that chair moving back and forth, J-10! Your spouse and friends will be sure you've lost your last marble, but you should have an increasingly serene expression on your face."