Quote

Quote from: Notat on 2010-03-25 17:54:33

Surly you recognize that one way people may want to "assess fidelity" is by how it subjectively sounds to them.

But that's not what fidelity is!

I think what I'll do is read this to indicate that you are not interested in adjusting your presentation style. I think your style limits your effectiveness but I think it is also fun for you.

Schoepenhauers list: 38 ways to  win arguments by cheating. This list is over 100 years old!

Quote from: Arnold B. Krueger on 2010-03-25 14:05:23

For the record, I try to avoid them.

@Arnold,

usernaim has written three vital words that I didn't think to, but they are the crux of it: black box testing. That's what we need. If you mistake this for Schoepenhauer's 38 strategems, I really think we're lost.

As for "If I could just find a few good people who knew what a masking curve or an audibility curve was and how to apply it to a technical test report!" - I created an auditory model for the assessment of coded audio for my PhD - yet there are several people here I'm not worthy to wash the feet of  - so I don't think we're lacking in this respect.

"You're asking for a lot of free consulting at a fairly high level of competence." - which is strange, because I thought nailing transparency in audio components was your life's work - certainly the reason for posting so much on the net.

It's not going to benefit me. I don't work in audio any more. It's just an interest for me now.

I suspect (and I'm saying this out of sadness, rather than to bate you) that it falls into the category of "too hard", so you're not willing to attempt it.

Quote from: John Eppstein on 2010-03-25 03:39:10

...When people using a conventional testing methodology such as ABX say that they can find no perceptual difference between an inexpensive consumer quality converter and a $10,000 mastering converter but an overwhelming majority of professional engineers can pick out work done with each (and unanimously prefer the professional unit)

Those sound "engineers" are not real engineers. They are not likely to have engineering training, otherwise they would trust ABX instead of their gut feelings.

Quote from: John Eppstein on 2010-03-25 03:39:10

...that tells me that there's something wrong with the testing methodology. (I'm not saying that ABX is an invalid or unuseful tool, I'm just saying that it has limitations...

That is the same as saying the world is flat.

Quote from: John Eppstein on 2010-03-25 03:39:10

I think that in some ways we're attempting to do the equivalent of brain surgery with a dull pocketknife. When people using a conventional testing methodology such as ABX say that they can find no perceptual difference between an inexpensive consumer quality converter and a $10,000 mastering converter but an overwhelming majority of professional engineers can pick out work done with each (and unanimously prefer the professional unit) that tells me that there's something wrong with the testing methodology. (I'm not saying that ABX is an invalid or unuseful tool, I'm just saying that it has limitations.)

When they make such claims without an ABX test to me it would seem the "engineers" are talking out of their arse. If the difference is so obvious it would be no problem to do it double blinded no? The limitations of an ABX seems to just be that it doesn't give "engineers"  and their following their special feeling of being better than the rest.

Quote

We do not throw out observation simply because it doesn't agree with conventional wisdom, especially when conventional wisdom is to a large degree based on simplification.

We do this all this time, it's called placebo affect. Not all observations are equal.

Quote

The Catholic Church tried that with Galileo.

That's funny from someone who falsely started to preach about the limitations about ABX. Make no mistake about it, you are the church here.

Quote

A real scientist tries to find out those things that he doesn't know. He doesn't simply point to the establish body of knowledge and treat it like scripture. That type of person is a pedant, not a scientist.

I think you have shown here you don't know the first thing about scientific method.

Quote from: John Eppstein on 2010-03-25 00:22:58

BTW, did you recap the power supply and do the bias adjustment on the Threshold? Because if you didn't you didn't give the amp a fair evaluation.

That would probably be a TOS 8 violation.

Quote from: hellokeith on 2010-03-25 08:00:55

However, would the distortions introduced in lossy codecs be more evident in this type of situation? Play a 128kbps mp3 file through that system turned up to 10 outdoors, would you hear the lossy distortions at a reasonable distance from the speakers?

In the end it's the SPL at the ear that could make the difference, not necessarily the power of the PA system. You can also go pretty loud with headphones.
I expect more effect from the room acoustics (reverberation) on the masking properties of the codec. It should be possible to simulate that at home with a reverberation (e.g. convolution) plugin.

Quote from: John Eppstein on 2010-03-25 00:42:35

Quote from: 2Bdecided on 2010-03-24 12:38:58

...snip stuff about valves/tubes...

The phenomenon you are referring to is known as tube microphonics and is caused by defective tubes...

Thanks John.

My point was that these measurements or characteristics are supposed to be defining audio equipment - or at least defining a threshold beyond which we can be sure it's transparent.

For the purposes of this discussion, I don't care whether it's because the tubes are broken, or they all do that - I care about whether the defined measurements catch this fault.

Since no one has been brave enough to properly define the measurements yet, we can't be sure.

Cheers,
David.

Quote from: 2Bdecided on 2010-03-24 12:38:58

the metal in the valves sings along with the music ... tap the valves, you can hear the tapping through the speaker.

I suppose you could call that reverb, but I call it ringing because it has a single dominant frequency. Either way, it's one very good reason to avoid tubes in all audio gear.


--Ethan

You can't just change that meaning simply because you want to call something "high fidelity" that clearly doesn't give out what you put in.

I mean, you're not seriously saying people can't ABX tape, are you?

The next question is which would they label high-fidelity? For me "high-fidelity" brings to mind my grandfather's open reel tube rig. That's the sound and era I associate with "high-fidelity".

Why not be more explicit and ask which has more "accurate reproduction"?

There's an old saying that to a sufficiently uneducated mind, modern technology appears to be magic. A corolary seems to be that to  a sufficiently uneducated mind, modern technology appears to be stupid.

Any sufficiently advanced technology is indistinguishable from magic.

Quote from: John Eppstein on 2010-03-24 22:56:01

Ah, but in the case of a pipe organ you're looking at the wrong thing.

Says who?

I was up in some pipe organ chambers last night, and what I saw belied just about everthing that you say.

Quote

In the case of a pipe organ the pipes do not function as single units, they are part of an array inside a tone cabinet.

Incorrect. Some pipes are in the open, and some are in cabinets. Furthermore, the cabinets are generally at least partially open in actual use.

Furthtermore, my discusison was of bass tones and subwoofers, and the corresponding pipes in a pipe organ are always out in the open.

Finally, the purpose of the cabinets is to be a sort of acoustic EFX box, IOW they are there to intentionally and discretionarily distort the sound. That puts your discussion of them in the same category as someone who complains about the poor frequency response of tone controls when placed off-center.

Quote from: John Eppstein on 2010-03-25 00:42:35

The phenomenon you are referring to is known as tube microphonics and is caused by defective tubes

This is incorrect. Virtually all tubes such as those commonly used in legacy audio and for EFX, are far, far more microphonic than their SS equivalents.  Tubes need not be defective tubes to be microphonic. There's a reason why shock mounts have been commonly used with tubes in critical applications all along.

Quote from: Notat on 2010-03-26 01:35:42

The next question is which would they label high-fidelity? For me "high-fidelity" brings to mind my grandfather's open reel tube rig. That's the sound and era I associate with "high-fidelity".

Why not be more explicit and ask which has more "accurate reproduction"?

Because high fidelity means accurate reproduction.

Quote from: John Eppstein on 2010-03-25 02:14:44

Ethan, how can you say that a $25 converter card that only publishes specs at 1kHz (presumably because the response at other frequencies is all over the map) is better quality than my $100,000 Studer that has very tight published (and verified) specs from 20 Hz to 20kHz?

So you haven't watched my AES Audio Myths Workshop video either? At 41:28 it shows specs side by side for a typical consumer sound card versus a Studer A-810 recorder. Guess which wins in every single category? Now, you could argue that the sound card specs are not very complete, and you'd be right. But what part of 109 dB s/n versus 74 dB (best case for the Studer) is confusing? My recent simple test with sine waves also shows a lot of info all at once in just a few FFT graphs, repeated here below for your convenience. The top graph shows the noise for one record/play generation, and the lower series of graphs shows distortion and noise for the original test tones and two sound cards.

--Ethan

Quote from: John Eppstein on 2010-03-25 03:39:10

I'm not saying that the electronic measurement equipment isn't good enough - I'm sure it can measure the signal quite well. The problem is that we don't know how to interpret the measurements properly and in some cases we may not understand what needs measuring.

Who is this "we" that you speak of?

--Ethan

You may think what you want, it's a free country. I'm not denying you the right to practice whatever religion you see fit - just don't try to sell it to me as science. I don't believe in creationism or astrology either. Or the assertion that tying little bags of pretty rocks to your speaker cables will make your stereo sound better. Although if you happen to believe that I've got a lot of scrap opal for sale.

Understand, EVERYTHING has limitations. Electron microscopes have limitations. The Hubble space telescope has limitations. My Tektronix scope has limitations. Why would you possibly believe that ABX is the only measuring tool that doesn't?

A real scientist, such as J_J (whom I have a great deal of respect for) is interested in discovering what the limitations are and devising means of surpassing them. He doesn't go around denying evidence just because it doesn't agree with his preconceptions. He does, however, think I'm kind of silly for discussing it with religious fanatics.

As far as your invocation of the "generations" argument vis a vis the soundblaster verses the studer...I think it is a false strawman.

First off, anyone who has ever used tape knows that cascading generations is to be avoided at all cost.  Otherwise, we'd have been doing non-linear editing and mixing a LONG time ago.

But the "soundblaster" problem is a two-fold problem.

The data storage and retrieval aspects are great, but it's the conversion process itself that's damaging.

Ethan, you need much longer analysis windows on your spectrum plots, especially those at low frequencies. Also, for higher frequencies you might use uniform frequency scales to make looking for harmonics easier.

Also, try this, make a set of tones of 250Hz + n * 500Hz (for n integer).  Use them all at once, do not overload, and plot the output, looking for anything at 500Hz.

Quote from: John Eppstein on 2010-03-25 02:14:44

Ethan, how can you say that a $25 converter card that only publishes specs at 1kHz (presumably because the response at other frequencies is all over the map) is better quality than my $100,000 Studer that has very tight published (and verified) specs from 20 Hz to 20kHz?

<snip technical test results showing how some fairly inexpensive cards perform at other frequencies than 1 KHz>

Which is supposed to prove exactly what?

What do sine waves have to do with real world audio signals?

And frankly, I'm glad to put up with a little bit of noise if the recorded audio sounds better.

That's one of the problems with defining THD as a component of S/N, BTW. The S/N spec doesn't actually tell you anything at all about how it SOUNDS.

Measurements are meaningless if you don't know how to interpret them.

And aren't "charts and graphs" a TOS #8 violation?

Quote from: Arnold B. Krueger on 2010-03-25 11:12:55

Quote from: John Eppstein on 2010-03-25 00:42:35

The phenomenon you are referring to is known as tube microphonics and is caused by defective tubes

This is incorrect. Virtually all tubes such as those commonly used in legacy audio and for EFX, are far, far more microphonic than their SS equivalents.  Tubes need not be defective tubes to be microphonic. There's a reason why shock mounts have been commonly used with tubes in critical applications all along.

Wrong. Microphonic tubes are defective.

The unfortunate fact is that the vast majority of tubes are defective to some degree. As to whether the defects are significant depends on the application. Since companies do not allow the return of tubes once they've been plugged in we have to make do with what we can get.