Time to catch up on some reader feedback to recent blog posts. I've responded privately to all the emails I've received, but thought I'd also pass along some of the comments here.
In my post Audio amp design: Do you tube? (Part 2) of August 8th in which I described some of my tube audio experiences, I mentioned my PCM63-based DIY tube DAC and its ultra-simple output stage. Monarchy Audio - a high-end audio company - responded by bringing to my attention a similar product that they make.
"We happen to have a tube DAC on the market using an architecture quite similar to the PCM63-6DJ8 in your article. In fact our newer generation uses the 24 bit PCM1704P-K that performs even better."
Monarchy is known for making affordable high-end equipment, but they're also known among the DIY community as a source for sometimes hard-to-find and discontinued components. In fact, I think that's where I bought the PCM63 DAC chip I used in my DIY tube DAC.
I received a number of replies to my August 15th post Engineer with a subwoofer, where I complained about my noisy video game-playing neighbor and contemplated methods of subwoofer revenge. Many recounted their own experiences with noisy neighbors along with a variety of other possible technical solutions.
"Perhaps your subwoofers would best be applied to cancel your neighbor's."
"Your idea of running interference to his sound is the answer, in my opinion. Don't take his signal and amplify it, as you said, he might like it. Run a different kind of annoying noise at a really loud level, which will disrupt the sound of the game as to make him lose his concentration. Perhaps a low frequency generator, changing the center frequency at random intervals. As a gamer, I'd hate being in the middle of a game and lose because some external noise was messing with my concentration."
"I hear moderate power RF with a directional antenna can wreak havoc on some gear :^)...."
"... Here's what I did, but I'm a HAM radio operator, which may be a prerequisite: I noticed pretty heavy thumping from the neighbor's speakers when I keyed my kilowatt transmitter with morse code into a dipole antenna hanging outside the apartments. My own stereo did the same thing, and looking at the speaker cones, I took the precaution to disconnect them when I went on the air. One night I decided to play with the neighbors even more and recorded some messages, which I replayed over the transmitter, using AM. "This is God, turn off your stereo," etc. It occurred to me that this could be even more fun nowadays, should you know what the game is about, and be able to insert messages of appropriate nature. Even though some EMI remediation in entertainment electronics has taken place in the last thirty years, I'm pretty sure that a kilowatt in the neighborhood is more than most of them can deal with."
"By the way really enjoyed reading the latest installment about your neighbour, mine is exactly the same except he enjoys listening to a strange combo of hip hop and show tunes until 4am! I find ear plugs an absolute necessity, either that or take out the local electricity substation with an EMP!"
In Oscilloscope waveforms as 'art', posted August 29th, I embedded a short video, "YouScope," which used a sound card to animate images on an oscilloscope. A reader recounted similar oscilloscope experiments back when he was in college.
"In college in the 70's I just used XY mode with a large RC filter on the Y axis, and connected to my stereo output. With the main audio input on X and the RC phase shifted output on the Y you can get lots of interesting circular shapes. "Dazed and Confused" by Led Zeppelin produced the best circles of any song due to the strong low bass notes."
And finally, in response to last week's post, Are audio cables guilty of sonic differences?, where I questioned whether many audiophiles' claims of routinely hearing differences among audio cables would hold up in court, one reader offered his thoughts.
"...it seems obvious to me that a blind experiment could easily be performed in front of a jury. The amplifier and related equipment could be concealed behind a screen with only the speakers visible to the jury--we're talking about interconnects, not speaker cable, aren't we. Two or more interconnects could be used and according to an ordering determined by the flip of a coin, either interconnect A or interconnect B could be used in sequential trials. The jury could be asked to mark A or B for each trial. Fairly straightforward statistics can then be used to determine the probability associated with the observed outcomes. The jury would then be presented with their collective results as best evidence.
Different people have different equipment, different furnishings, and, of course, different ears and brains. Nevertheless, I have long believed that people can hear and appreciate sound reproduction much more than they think they can. I think that there is a kind of "reverse snobbery" that says "spending all that money is a waste... I (or nobody) can hear the difference". People will spend $1000-2000 on a whole stereo system having no idea how much more compelling the experience might be with a better system. It's pleasant to see Bob Dylan from lawn seats but it's an entirely different experience from the third row. It's still a question of values, but people think nothing spending $10,000-20,000 more on a car for differences in experience that I think are much less compelling."
Thanks to all who responded. I welcome all comments and suggestions. You can send them to me at firstname.lastname@example.org.
Also, as a reminder, if you'd like to stay up on each week's postings of the latest news and articles but don't always have time to visit the site, you can subscribe to the Audio DesignLine weekly newsletter.