many treat it with disdain, only poor deluded objectivists use test equipment afterall
Don't worry, there are still plenty of opportunities to make a mess of chip amp designs and I imagine some designs could also sound quite reasonable.
I haven't used chips for about 10 years now and I keep thinking to revisit them just to see how how they compare.
Fas42, unfortunately, it appears that only you and I are willing to contribute positively to the problem of getting a better measurement that more closely fits the human ear's capability of discernment.
Frankly, I am somewhat at a loss as to where to go next. I have been on the trail for about 40 years, and I am tiring out.
This doesn't mean that many serious audio designers will not try to find better approaches to amplifier design. We do it continually.
Fas42, I might say that I agree with you that power supply is very important.
This is why I make such large supplies in both my preamps and power amps.
The power supplies for the CTC Blowtorch preamp are 3 stage passive, then 3 stage active for EACH LINE CHANNEL and PHONO channel. It fills the box!
I do this effort to minimize ANY potentially bad contribution of the power supplies to the preamp's sound. Works for me!
Frankly, I am somewhat at a loss as to where to go next. I have been on the trail for about 40 years, and I am tiring out.
This doesn't mean that many serious audio designers will not try to find better approaches to amplifier design. We do it continually.
Fas42, I might say that I agree with you that power supply is very important.
This is why I make such large supplies in both my preamps and power amps.
The power supplies for the CTC Blowtorch preamp are 3 stage passive, then 3 stage active for EACH LINE CHANNEL and PHONO channel. It fills the box!
I do this effort to minimize ANY potentially bad contribution of the power supplies to the preamp's sound. Works for me!
Where exactly is this 'fashion audio show' that you accuse me of participating in?
I don't advertise, I don't design the outside looks of the products I am designing, I don't even depend on my own measurements for comparison with other competing products.
What I do is try to further understand what I can do to make better audio products, regardless of their price range.
It is rather disconcerting that you accuse me of being 'intellectually bankrupt' yet you have been to my place, seen my test equipment, noted the textbooks, journals and engineering papers that I have all over the place. What do you think that I do, except try to make better audio designs?
I don't advertise, I don't design the outside looks of the products I am designing, I don't even depend on my own measurements for comparison with other competing products.
What I do is try to further understand what I can do to make better audio products, regardless of their price range.
It is rather disconcerting that you accuse me of being 'intellectually bankrupt' yet you have been to my place, seen my test equipment, noted the textbooks, journals and engineering papers that I have all over the place. What do you think that I do, except try to make better audio designs?
It's not a "show" (although there are fashion audio shows, I just went to one here in Chicago), it's a market segment. An aging, shrinking market segment. Since I didn't accuse you personally of being intellectually bankrupt, we may have a reading issue. As I get older, I am more and more sympathetic to your vision problems.
Lots of turnover in those businesses. Look at a list from 10 years ago and then today- most of the old ones will be gone. Lots of dreamers, very few financial successes.
This was a subject of a seminar given by Stereophile at the recent Axpona show- it was telling that the audience was almost entirely over-50s.
This was a subject of a seminar given by Stereophile at the recent Axpona show- it was telling that the audience was almost entirely over-50s.
I see a lot of grey in a number of areas of personal interest these days, among them audio and "classical music" performance. And yet there is renewed vigor in seemingly almost-antiquarian areas like vinyl, analog synthesizers... a puzzle.
I suspect many read the recent headphone reviews in Stereophile. A recurring point made was that, while acknowledging the primacy of the fashion accessory function of the infamous Beats products, the "kids" were spending substantial money on an audio product, presaging purchase of more equipment in the future --- or so the writer hoped.
Although I'm not trying to hang out with appreciably younger people as part of a denial process, at least not consciously, it is amusing when I wind up in, say, a chatroom frequented by mostly younger folks and, for a time at least, am taken to be somewhere close to the median age. Last night I commented on having known, distantly, a figure involved in a scandalous drug overdose death of a famous folk-rock figure, this remark provoked by someone playing a fairly recent selection by his son. Someone said Wow! Just how old ARE you??
EVryone seems in such a rush to do away with this pastime we all clearly enjoy. While I am sure that many great ideas have been spawned in this forum, it is probably like many things in that most of what you find here has trickled out of the "show" and into our gear. I do not say that to speak negatively against the intelligence and capability of anyone here, but i must consider what we would be building/doing without the likes of Curl, Pass, and others who frequent this place and plant seeds of possibilities. I must admit I would not be doing it.
Although I'm not trying to hang out with appreciably younger people as part of a denial process, at least not consciously, it is amusing when I wind up in, say, a chatroom frequented by mostly younger folks... Someone said Wow! Just how old ARE you??
That was the amusing thing about my Austin live music days- I was always, by 30 years, the oldest person in the room. Only exception I can think of is Lee Barber shows, which seemed to attract an older crowd, maybe because the music was more world-weary and less accessible.
Merely implies that it's a fashion industry, which reached maturity.
Less Timex, more Rolex.
Audio shows are not benchmarks, and Stereophile is not a standard, but merely a self-overrated glossy mag.
Outside the US, only audiophools read it.
There's +1.5 billion Russians and Chinese eager to get what others had.
They're the buyers now, in every luxury market, and audio is just that, always has been.
(+100k stereo-set people I'm acquainted with, have zero interest in shows & audio magazines)
Possibly not. We can also play with the eq not just on that loudspeaker but on the adjacent ones, so they match. But since the owners are paying a few million for the sound system, we will replace it if it is defective. However due to manufacturing tolerances it will take additional testing to determine if it is just a low performer, out of spec or actually dead.
I think we have ruled out wiring mistakes. The 1000 hertz impedance is correct. By ear it does not match any of the other units.
The crew on site was set up to do termination and wiring mistakes testing. Checking a tweeter at 100 feet is a bit tricky at best, throw in construction site noise and things get very interesting.
(They found half a dozen wiring issues. But we test for stuff others don't seem to know about.)
ES
Hand-held "sound camera" shows you the source of noises
This appears to be pretty much a near-field device, but the article alludes to larger devices. Perhaps some parabolic microphone arrangement could do an acoustic comparison of adjacent drivers and at least aid in diagnosis? Or maybe you're doing that already.
John,
This is my idea about testing - no idea if it would produce useful results.
The human mind seems to have an almost uncanny ability of being able to 1) notice patterns and 2) notice elements that spoil a pattern.
I was just thinking if I had unlimited access to sophisticated test equiptment I would be playing around with ideas based on these abilities.
My first guess would be to used the very best low level spectrum analysis equipment and instead of just using 1Khz as a test signal I would try 1.1Khz 1.2Khz 1.3Khz etc to 1.9Khz
With each of these test tones I would look for small variations in the harmonics spectrum from bands from 2Khz, 3Khz, 4Khz etc to 20Khz.
Would do this test initially on two Identical Hi end amps one of which had a "subjective floor" built into it on purpose - my choice initially would be one unsnubbersed bypass cap because I particularly dislike the "sound" this creates but the chosen "floor" could be anything the designer decides.
It would be fascinating for me to actually measure what my ears can so clearly hear. I have no idea if this kind of testing is already being done in but would be interested what the experts here think of the idea.
As it happens I have no expectation of ever using such equipment and don't really mind if I don't. My current method of testing theory in spice and real world with my ears seems to work OK for me ( but perhaps I'm living in a fool's paradise
)mike
As I think you know there is a manufacturing tolerance allowed for variation in final parameters. So we can clearly measure the individual drivers level vs. frequency and compare that to the others to see what the variation actually is. The best method to do that what lots of noise around is TEF. This uses a swept sine wave and a tracking filter. The trick is that the filter sweep is delayed by the time equal to the distance to the driver under test. This allows great rejection of random noise.
To determine that distance we can either use a visual device or better is the delay location feature in the SMAART software. (It is based on auto correlation last I paid any attention to it.)
The field termination crew did not take any of this gear with them. After termination then the tuning crew goes to work and they have that gear and more.
The issue was that ears are great for a lot of stuff, but precision really does require test equipment. The ears say there is a problem, the gear with a bit of luck will tell us exactly what the issue is.
So if we are lucky it is manufacturing tolerance and can be eq'd out.
Not so lucky it is something stupid that can be fixed without having to visit the loudspeaker box.
If it is in the weather-sealed loudspeaker box, we have to get a complete replacement made before we spend the money getting to the bad speaker.
Once the bad speaker is down, we dissect it to find out what went wrong and who gets the bill!
ES
I like the home made laser cutter. It disturbs me that any random DIY'er can get 1.5W lasers.
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