Does the police investigate an accident unless they know an accident happened?
I would have thought they would need to establish that such an event took place and then find out why.
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THE BEGINNING:
I think we should make it simple as we did back earlier in the thread and state:
It can be done by two resistors and a cap - it's not that hard. Aim to be down -1.3dB to -1.5dB down @ 20KHz.
That's all.
Just try it -it can't be that hard to do.
Cheers, Joe
PS: DIY is about making music.
I would have thought they would need to establish that such an event took place and then find out why.
_________________________________________________
THE BEGINNING:
I think we should make it simple as we did back earlier in the thread and state:
It can be done by two resistors and a cap - it's not that hard. Aim to be down -1.3dB to -1.5dB down @ 20KHz.
That's all.
Just try it -it can't be that hard to do.
Cheers, Joe
PS: DIY is about making music.
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Shinja has already done it in the easiest way and Peufeu has explained it very well. But noone cares because noone trust sims 😉 It's bunny hopping!
When i see a measure i can post a counter-measure if i want to discuss it 🙂
My advice about dual-typo maybe will help in both ways (author's and technician's).
And it can be done without measure but just using the same method as first post here. Easy.
IMHO it's a good test. No?
I use computer modelling all the time, so wrong again... sigh.
But I always have to verify they are giving me the correct results.
So really, is that where it ends for you? OK, so be it. Then why are you still here if you have nothing more to add. I am only saying because I don't understand why you are hanging around. I can only think of one good reason and that is you want to show us up as nitwits.
OK, you have won. Happy?
Now please, leave it at that, OK?
I am asking you nicely to leave it at that, you have made your point.
Anybody else out there ready with a soldering iron?
Cheers, Joe
PS: I wonder if anybody has ever simulated the human ear - would it perform the same as a real ear?
PPS: We have discovered (not measured) that the human ear can hear well above 20KHz by subjected listener's with 12KHz limitation, to square waves subjected to a low-pass filter well above 20KHz and they can easily hear it. Nobody knows why. Seems that humans can hear rate-of-change well above 20KHz - and we don't know why? There is some kind of latching mechanism that finds the leading edge of a waveform, even when that rate-of-change is well above our understanding of what frequencies we are supposed to hear.
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No. I just added a PPS - please read.
Think about it, IEC 60318-1 is simply a tool - but it has limitations that will be subject to those things that we still don't have a full handle on.
Simulations only work when known boundaries are dealt with. Right?
Take nuclear fission - they can be simulated only because they did a lot of testing. What if they had not done the tests, or not done enough of them. Does that means they know everything about nuclear fission? Of course not, but they know enough that those simulations can be made into danger for us. So even simulations work within a targeted envelope - they don't tell us things we still don't fully know.
But they are awfully useful - I use them myself. And simulations can indeed answer a lot of "what-ifs" in a short time, in design work. So they can be very powerful - to an extent.
Cheers, Joe
PS: Talk to mathematicians and I learnt something a little surprising, and a little disappointing, they use numbers that are not absolute. I forget what they call them, there is an official term for them, but one of the guys I talked to called them "fudge numbers". Oh yeah, they are like 'constants' that are made up from experimentation and experience etc, and they have to be tweaked from time to time.
Not sure how that PPS relates either to your question or my answer.
Sure. But you wrote "I wonder if anybody has ever simulated the human ear". I replied by referring to an industry standard that shows it is being done all the time - something I am sure you are familiar with as a loudspeaker designer. Of course it is not perfect. But you didn't ask for a *perfect* simulation of the human ear - and we will never get a simulation of anything to be *absolutely* perfect.
Right.
Sure. But in a well-understood domain (and audio electronics and digital systems have been a well-understood domain for at least 80 and 35 years, respectively) they work well.
Without any context that paragraph is somewhat meaningless. Mathematics is a rather wide field...
Any links/references? I only know of one anecdote John Curl keeps repeating about the single informal experiment with 3 people that could well have been plagued by the same intermodulation issue that explained the debunked Oohashi study.
Are you going to use a soldering iron any time soon?
This is all old hat, is it not?
This thread was about trying something out called DIY - and indeed some will do it who will never understand why it works and never will. Isn't that more important to do first, at least help them out first?
Can we move on...?
Cheers, Joe
PS: Thanks to those who have been sending me emails of support - you know I appreciate it and thanks for everything. No, Pete, I don't think they know the expression "thinking outside the box".
.
This is all old hat, is it not?
This thread was about trying something out called DIY - and indeed some will do it who will never understand why it works and never will. Isn't that more important to do first, at least help them out first?
Can we move on...?
Cheers, Joe
PS: Thanks to those who have been sending me emails of support - you know I appreciate it and thanks for everything. No, Pete, I don't think they know the expression "thinking outside the box".
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Of course, like audiofool theories but it isn't the case (i hope).
It's audio..basic BF electronics. Anything alien here.
Sims work well in BF if you have basic skills on it.
Please don't tell me the story about sims. That's typical audiofoolish statement.
Go ahead.
This is random spraying and a big lol. C'mon, again this story? Post some reference (non wikis*it).
Can be you, with my dual topology easy to test.
It can affort your thesis very well.
Ready?
Debunked?
Sometimes the "debunking' is more flawed that the "debunked.'
http://www.q-audio.com/johncurl.pdf
BTW, this was figured out even before John Curl and he won't deny that either. There was a loudspeaker manufacturer in the 70's that did similar tests - actually, don't take anybody's word for it, it's not hard to do with square waves.
Off to bed.
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Pergo, I have decided that I am no longer going to respond to anything you say - that "fool" stuff has totally alienated me - so au revoir.
Sometimes. Sometimes it is simply a case of the original research being flawed. That is why we need peer review. And peer review has shown the Oohashi study was flawed. John Curl doesn't seem to have published anything peer-reviewed about this specific topic (apart from some anecdotal statements)
As I wrote:
Indeed not hard to do - much harder to replicate it under conditions where you don't get intermodulation products in the audible range. Every time people have succeeded in eliminating the intermodulation products, the "ultrasonic" effect has disappeared.
Yes, there has been hundreds of tests, ever since the 50's, all well documented and peer-reviewed, and none of them have found evidence for the audibility of frequencies above 22 kHz.
Jan,
FYI - Joe Rasmussen did not name the effect after himself. A small group of us were referring to what we were hearing as simply,'the effect' on an Oppo thread when one of the posters suggested we give it some kind of name. I then suggested calling it the 'Rasmussen Effect' in recognition of Joe, who had brought it to our collective attention. I wish everyone to be clear that Joe himself had nothing whatsoever to do with the naming.
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Shinja have had an attempt to advise (as I understood) against using caps in between an opamp input and GND (his post nr. 5).
This advise tell me that he misunderstood what about this filtering technique we talk about here and now.
Here in this approach, is not at all about using a cap connected to GND. But using this cap in between the differential outputs of the DAC chip, and of course in between the the +/- inputs of the I/V converter (if one use an active I/V setup).
So...
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Very right! I can confirm this too. Anyway, one may read the respective posts in the Oppo thread, if one feel the need to clarify this out of topic task.
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Thanks, Jesper, for this tip about the Wima FKP parts. I used FKP-2 in my experiment because I happen to keep selection of them readily on hand for just such purposes. I was able to quickly satisfy my curiosity (within minutes) about the effect Joe was describing. To my pleasant surprise, he was right.
so....read again, because Shinja get a prepreprepreview and Peufeu an easy implementation with demonstration (with ideal CS..think about how worse will get with real CS).
Audible positive effect doesn't mean a positive electrical effect (because ear is not a mic...brain rules).
If you like ringing it's ok..but electrically is the worst mod ever. Capacitance effects at I/V(OP) input are well known, as all OP input.
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