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Old 16th April 2003, 07:48 PM   #1011
SY is offline SY  United States
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Pan, at the time of my epiphany, when I started doing some rigorous controlled testing to prove that Lipshitz guy wrong, I was 28. That was (gulp!) twenty years ago. I've lost a few kHz to presbycussis over the years (I'm probably topping out at 15K these days), but I still have no trouble identifying the string gauge on my guitar by the sound.
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Old 16th April 2003, 10:14 PM   #1012
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Default Re: Re: Re: purplepeople wrote:

Quote:
Originally posted by Pan

I dont know where you get 6kV from.

/Peter

slew rate=6.18*freq*V(out)peak
 
Old 16th April 2003, 11:24 PM   #1013
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Quote:
"In fact, if the test was of any use whatsoever you most certainly should have been given a graph"

What do you talk about???
I know this may come as a surprise, but I try to talk in areas where I have some training/expertise .... a novel concept for a couple of people here, I suspect.

I do not comment on the electrical theory side because compared to the masses here I am an idiot/novice.

Medicine, however, happens to be what I do for a living so you will forgive me if I felt bold enough to comment.

Properly performed audiometry should be done in a sealed, sound-proof booth, using a combination of sine-wave and white-noise sources in a combination of ascending/descending SPL patterns. The end result should be a calibrated graph over the test frequency range. And this should be done after someone has made sure your ears are not full of wax!

A simple comment, "your hearing is 10dB better" on it's own is not too helpful. I grant, it's better than your GP saying, "jeeez ..... your as deaf as a post", or even worse you not hearing the GP at all

Again, please read what I actually write, cf what you might infer. I have made no statement about your hearing per se, just what can be reasonably concluded from the information provided and more importantly, what people should be looking for if they want to assess these things properly.

"Jeeeez... once again!" ....... Indeed

regards
mark
 
Old 17th April 2003, 01:19 AM   #1014
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Default Too Gutless To Say Anything Meaningful....

Quote:
Originally posted by mikek
bnxvcnfggffg
Ok, so you are an idiot then.
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Old 17th April 2003, 01:44 AM   #1015
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Default Not Plecebo Effect....

Quote:
Originally posted by Bane2871
Personal Anecdote: I do a lot of cycling. About a year a go I tried a new energy bar. About 20 minutes after I ate it, I started to feel significantly better, stronger. I tried it again a couple days later, same result. I've noticed that when I eat this bar prior to riding, I feel better, ride faster (yes, I use a cyclometer so I am actually faster). The question is this: Does the bar actually have that much of an effect or is it just a placebo effect? I don't know enough about what is happening biologically/chemically to know the ACTUAL (REAL) effects. However, I DON'T CARE (aside from any possible negative effects). I don't want to know. All I know is that I ride faster and feel better. If it is a placebo effect, at least partially, I don't want to know. That knowledge might reduce the effects, which is something I don't want to happen.
Hello Bane2871,
20 years ago I used to race cycles, road and velodrome.

Sundays were post race day, and the day for some easy longish distance riding to get the soreness out.
I would ride all over the city and drop in and see a few mates, and of course we would have a beer together.
Being ultra fit, the alcohol would go straight to the head, and give that happy sense of well being, however getting back on the bike was a whole different thing.

After just one 375 ml bottle of standard beer, all my strength was taken away, and even moderate climbs were a task.
It seems that even that small amount of alcohol inhibits oxygen uptake dramatically.
However after about 15 minutes back on the road, the body processes and removes this alcohol, and I was back to being completely sober again - until I dropped into the next friend's place that is.

Try taking a biddon of very strong tea with castor sugar dissolved into it.
This gives caffeine boost, sugar boost, wets the mouth and makes you feel good too.

Eric.
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Old 17th April 2003, 06:12 AM   #1016
Pan is offline Pan  Sweden
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Default Re: Re: Re: Re: purplepeople wrote:

Quote:
Originally posted by mikek



slew rate=6.18*freq*V(out)peak
Maximum ouput voltage swing has NOTHING to do with slewrate.
Still donīt know what you talk about.

An opamp or video buffer with several hundreds of MHz BW and slerate of 2000V/uS must be able to swing several kV as well if I get you right???

I guess Elantec, BB and AD is just making those numbers up then..

/Peter
 
Old 17th April 2003, 06:16 AM   #1017
Pan is offline Pan  Sweden
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Quote:
Originally posted by mefinnis


I know this may come as a surprise, but I try to talk in areas where I have some training/expertise .... a novel concept for a couple of people here, I suspect.

I do not comment on the electrical theory side because compared to the masses here I am an idiot/novice.

Medicine, however, happens to be what I do for a living so you will forgive me if I felt bold enough to comment.

Properly performed audiometry should be done in a sealed, sound-proof booth, using a combination of sine-wave and white-noise sources in a combination of ascending/descending SPL patterns. The end result should be a calibrated graph over the test frequency range. And this should be done after someone has made sure your ears are not full of wax!

A simple comment, "your hearing is 10dB better" on it's own is not too helpful. I grant, it's better than your GP saying, "jeeez ..... your as deaf as a post", or even worse you not hearing the GP at all

Again, please read what I actually write, cf what you might infer. I have made no statement about your hearing per se, just what can be reasonably concluded from the information provided and more importantly, what people should be looking for if they want to assess these things properly.

"Jeeeez... once again!" ....... Indeed

regards
mark
What I didnīt like about your post the comment "to be of any use at all.." (or something like that). In order to make such a comment it seems to me that you would need to know the purpose of the test, which you dinīt know.

Simple as that

Thanks for your expertise comments in this latest thread though, most of the points you make was done in the test

/Peter
 
Old 17th April 2003, 08:50 AM   #1018
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to this forum, and it's good to see a range of opinions in the subjective/objective debate. Here goes:

1. It's important to be able to say "I can't hear a difference". Michelson & Morley presumed the existence of the ether which they were trying to measure, but had the courage to say their experiment had failed. From it we learned a lot.

I assume we've all made many upgrades and tweaks to our systems over the years, and if you're like me some changes made a night-and-day difference, and others were not. Personally, I want as many of the former and none of the latter as possible.

Ultimately, being able to say "it makes no difference" is essential to avoid being taken for a ride by charlatans.

2. I'm very happy - it's my normal practice - to let a subjective decision be the final arbiter rather than objective measurements. I'm even happy that this can be an unreliable and unrepeatable experience, and accept that this sometimes leads to flattery instead of accuracy.

Here's the 'but', though: there's a tendency to attach technical statements to subjective judgements e.g. "negative feedback makes your amplifier sound bad". This sort of statement implies there's an underlying physical mechanism at work, and this *must* be the subject of scientific inquiry. To make technical statements, but be unable to justify them technically, is not something I can stomach.


Cheers
IH
 
Old 17th April 2003, 09:58 AM   #1019
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Default Re: Re: Re: Re: Re: purplepeople wrote:

Quote:
Originally posted by Pan


Maximum ouput voltage swing has NOTHING to do with slewrate.
Still donīt know what you talk about.

An opamp or video buffer with several hundreds of MHz BW and slerate of 2000V/uS must be able to swing several kV as well if I get you right???

I guess Elantec, BB and AD is just making those numbers up then..

/Peter
Voltage swing has nothing to do with slew rate, that's right,
but slew rate has a lot to do with voltage swing. Any op amp
can swing almost rail to rail voltage at sufficiently low frequency.
However, to do this also at high frequencies it needs a good
slew rate. For an output signal v(t) we need a slew rate of
max dv(t)/dt, which for sine waves simplify to the formula
mikek posted.
 
Old 17th April 2003, 12:54 PM   #1020
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Cool welcome

Welcome, Ian Harvey.

You made a very valuable contribution to this thread.
In fact, you almost took the words out of my mouth, because I'd say the same.
Stick around, this is still going strong.
In the end, we may even find that the Bryston amp plays much better than the Onkyo AV amp, even at low volume!
 

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