Enclosure resonances, not a big deal?

[planet10]

Originally posted by xpert
I'm really impressed how far we can discuss without understanding each other. I'm talking not of a soley signal "in the jungle" but about a deviation of amplitude response. That is that the amplitude vs frequency plot shows some +/- 0.3dB ripples - one or two of them.

A standard FR measurement tells us nothing about this stuff, it is far too course grained. What i want to see, is how these things affect the response some 40 dB down (nominal). Plug that into you calculator and tell me how a FR measurement is going to tell us anything.

I'm pretty sure i know where you are coming from -- if the only tool you have is a hammer, you treat everything like a nail.

dave

[xpert]

Originally posted by planet10


A standard FR measurement tells us nothing about this stuff, it is far too course grained. What i want to see, is how these things affect the response some 40 dB down (nominal). Plug that into you calculator and tell me how a FR measurement is going to tell us anything.

I'm pretty sure i know where you are coming from -- if the only tool you have is a hammer, you treat everything like a nail.

dave

Hi,

if that doesn't tell what else? The ear and it's associated brain ain't capable of more. But less. Once again, the response curve IS the system in it's linear part. Anything else is derived from that, You know?

so long

[dlr]

Originally posted by planet10


The differences between merely good hifi & really great hifi are happening 30-40-50 dB down... A gross frequency response is not likely to show the absence or presence of something 40 dB down let alone give you enuff information to know what it is.

20 dB is not good enuff for me...

dave

I'm curious. What do you think is occurring at 50db down in the linear part that is not good enough for you and does not show up in either the linear FR or show up as group delay change?

Dave

[gedlee]

Originally posted by xpert

Once again, the response curve IS the system in it's linear part. Anything else is derived from that, You know?

You keep saying this and its incorrect. It's ONLY true if 1) the system is minimum phase (which in acoustics in generally NOT true) or 2) you also have the phase response. The "response curve" is generally not shown with phase and even then non-minimum phase aspects (which are audible) are often impossible to detect visually.

You claim such supreme eXPERTise, but you get even simple stuff like this wrong.

[xpert]

Originally posted by gedlee


You keep saying this and its incorrect. It's ONLY true if 1) the system is minimum phase (which in acoustics in generally NOT true) or 2) you also have the phase response. The "response curve" is generally not shown with phase and even then non-minimum phase aspects (which are audible) are often impossible to detect visually.

You claim such supreme eXPERTise, but you get even simple stuff like this wrong.

If You would have read my posts You might have seen that I always mentioned the linear regime in ONE word as to say

A) group delay
and
B) amplitude response

That is what I meant could haven been understood as what I mean with "response curve". I wrote it so often in the lenghty way that I had the hope that including You everybody even if of minor expertize would simply know. You may think of it as me trying to set a standart in understanding the word: linear response.

And - I do not claim that "expertize". You get it wrong. What I do is to show weaknesses in marketing claims. That doesn't need to much brains.

[gedlee]

Originally posted by xpert

And - I do not claim that "expertize". You get it wrong. What I do is to show weaknesses in marketing claims. That doesn't need to much brains.

No, not when you just make up things.

[xpert]

Originally posted by gedlee


No, not when you just make up things.

As I really am a challenge for Your understanding please let me referre to my posting #135:

http://www.diyaudio.com/forums/showt...22#post1837922

From that on the talk concentrated on how to identify linear distortion and not to characterize it. Identification could be done with soley amplitude.

'Think we've got it now.

[planet10]

Originally posted by dlr
What do you think is occurring at 50db down

I listen to music, and way down is where the subtle details of the music live, the subtle details that really help with verisimilitude. On the other side the removal of grunge that hides this stuff relieves our flight/fight reflexes from having to work as hard. We are more relaxed and enjoy the music more.

dave

[dlr]

Originally posted by planet10


I don't know about you, but i listen to music, and way down is where the subtle details of the music live, the subtle details that really help with verisimilitude. On the other side the removal of grunge that hides this stuff relieves our flight/fight reflexes from having to work as hard. We are more relaxed and enjoy the music more.

dave

You should be above that first part that is a not very subtle attempt to belittle. I won't get into a debate about who listens to what and how. It's pointless and a bit conceited.

Grunge isn't a very well defined term. I suspect that no two people would define it the same way. I cannot infer any clear meaning of your definition of it and I doubt that it's quantifiable. How can one argue for/against an ambiguous term?

As for the rest, it doesn't provide anything not explained by changes in the linear part of the system response. Small crossover changes can provide changes in the perception that you describe. Painting dots or stripes on a driver make a measurable change in the frequency response that may be perceptible (or not). And I can't recall reading any references you might make to the distortion profile, so it seems fair to assume that you are referring only to the linear response and not any non-linear distortion.

Dave

[badman]

Originally posted by gedlee
I was refering to the fact that you continually criticise with no factual basis for your comments and no supporting evidence being offered. In fact, even your credentials to make any statements at all are unknown. Mine are public knowledge, posted for all to see. For all I know you have no training or experience to make the claims that you make other than your word that you are an "XPERT" from Afganistan (previously Austria I might note). Praytell, please fill us in, noting primarily points which can be verified, like publications and the like.

I should also mention for other readers that I was E-mailed on the side with warnings to ignore "Xpert", that he is German, and has been baned from numerous sites there for his actions. I have tried to ignore you, but you seem intent on getting my attention. Since you seem inclined to follow me around disagreeing to all of my posts I think that its fair to ask what right you have to do so.

Doc...

Arguments of expertise are a fallacy. I have no 'credentials' per se (beyond some years of experience) but can assemble a decent argument on many of the points under discussion.

Ignoring "Xpert" is the best route if you're bothered by his behavior. Anyone who uses such a moniker seems to me to be too arrogant for their own good. There's a saying, "The more you know, the more you realize how much you have left to learn" (it's been paraphased dozens of ways).

Regarding level perceptibility, testing I've seen was done with non-music signals. That alone separates the test from the usage environment, like a wind-tunnel vs. a racetrack vs. a road with cars. I do a number of tests when testing small items. One of the most important is long-term behavioral. Do I still enjoy the item in question after the novelty has worn off? Do I find myself focusing on one aspect of the sound? Do I listen to more or less music?

Obviously it's not an easy test to perform with multiple subjects, and has many factors applied, but that's why it must be longer duration. If my longer-term musical satisfaction increases, more attention is spent on the whys and wherefores. If I find my rig less enjoyable, the change is reversed, or further investigated.

Blind testing is an important validation step... sometimes. Just as with the THD wars, the ears have it all over the microphones, as far as musical enjoyment goes.