May I assume from your wording that this is an experiment that you've never actually done? If that's the case, how do you know that the results of this "test" will correlate with 'unpleasant, offputting or at least dulls or deadens the sound'?
If I'm mistaken and you have actually done a real experiment, please outline what you tested and how, and how you determined the correlation to 'unpleasant, offputting or at least dulls or deadens the sound'.
I would hate to think that this is just one more thing you've arbitrarily pulled out of... uhhhh... thin air.
If I'm mistaken and you have actually done a real experiment, please outline what you tested and how, and how you determined the correlation to 'unpleasant, offputting or at least dulls or deadens the sound'.
I would hate to think that this is just one more thing you've arbitrarily pulled out of... uhhhh... thin air.
Au contraire, I've mentioned numerous times where the issues are; power supplies, insufficient resistance to interference, poor quality connections, suceptibility to vibration. There is no one cause, there are a number of small, and large, weaknesses throughout the system, all of which have to be addressed in an appropriate way, until the quality is sufficient.Given your claims of how clear it is, i'm surprized you dont have any idea what the cause is ...it seems youve spent a great deal of time examining somewhat random collections of equipment to get to the bottom of it, yet have come up empty-handed. how do you expect someone to be interested enough to spend money on it?
If a car is supposed to reach 100mph, but can't, what's the answer? It could be wind resistance, lack of power, binding brakes, low tyre pressure, sticking throttle, transmission fluid low - the engineer looks at each aspect in turn, until all anomalies are sorted out, that's the approach that works ...
Correct. My experience is that inadequate power supplies correlate strongly with audible distortion in the treble region, therefore this seems a reasonable method of testing such.
I test by listening, that tells me what I need to know. Beyond that, there appears to be a need, as mentioned earlier, to quantify the performance attributes of equipment that performs well vs. that which doesn't perform well in a subjective sense, for others to appreciate the differences. This is just one step towards that goal ...
Frank,
Testing by listening is all fine, but it can only be the last step in the design process, and only after you measured the heck out of everything measurable.
To come back to your statement that inadequate power supplies correlate strongly with audible distortions in the treble region. How do you know that a power supply is inadequate without having done measurements? And wouldn't it be informative to first try to measure those distortions in the treble region, before trying to correlate them with an audible signature?
Testing by listening is all fine, but it can only be the last step in the design process, and only after you measured the heck out of everything measurable.
To come back to your statement that inadequate power supplies correlate strongly with audible distortions in the treble region. How do you know that a power supply is inadequate without having done measurements? And wouldn't it be informative to first try to measure those distortions in the treble region, before trying to correlate them with an audible signature?
Well it's pretty easy to measure just about any anomoly you want on a typical SET at normal listening levels, how to separate the "dulling" ones from the ones that bring the GEB to tears would make an interesting exercise.
How did you know that the power supply is/was 'inedequate'? Did you measure it under power, what did you see, why doesn't it effect LF as we know that the lower the frew, the more you see effects on power supply?
Is there ANYTHING substantial you could tell us?
jan
jan, dont you know that all meter readers care about is THD using sinewaves and uncorrelated noise? i'm surprized at your lack of understanding of these matters
the technology may well be there, we just need to teach the boffins how to use it correctly
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In a measurement sense, no - I haven't the access to the test equipment that many of you here do, this is purely carried out at the hobbyist level.
In a subjective sense the adequacy of the power supply is demonstrated by the tonal qualities in the treble region not altering as the volume is raised and lowered. My first serious amplifier showed a very precise point in the SPL range, for a particular recording, where this tonal character changed. Some basic investigation indicated strongly that the power supply was insufficient, so I improved the connections, its energy storage, and high frequency impedance. The recordings that had been a problem were no longer so - QED ...
LF would be affected, but I'm concerned with the tonal qualities of the bass notes, which are largely dictated by the higher harmonics - we're back to the treble again.
Does standard 3-tone IMD use variation of the relative levels of the frequencies as part of the testing process?
Well, I did design and build gainclones, using very high capacity power supplies, to turn some speakers into something close to active beasts ... but didn't put them into fancy metal boxes, with 1/2" thick walls - so I guess that doesn't count,
...Edit: I've also mulled over the idea of a 2.4kW into 8R amp as an exercise, on another forum - possibly linear, possibly class D, per Bruno's ideas. Biggest problem is motivation ...
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Gerfelnach! And here I have wasted all that money!
Bad news this week is I may have a speaker with a bad tweeter. It is mounted 170 feet in the air with no catwalk to it. My guess $20K to change it. Now how it passed the manufacturer's tests, my tests before shipping to the site and then the on-site before hanging test is an issue that will be be looked at once we know the precise failure mechanism.
So maybe I should just go to listening tests only. Surely that will be a better method. (Sarcasm for those who might be confused.)
ES
So you have no idea whether the PS has anything to do with it, it's pure speculation. I see. And you want us to build up specialised test equipment to chase - what exactly?
jan
increase the size of the power supply caps of course!
dont you know anything?!
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