Blind Listening Tests & Amplifiers

[mrfeedback]

Mikek,
Your profile says things like -

Biography - asdfsffds
Interests - fdsfdsddfsad
Occupation - adrfwefd

Can you please translate that for us ?.

Eric.

[mefinnis]

I've left this thread alone for some time as the content has descended beyond pointless, however, I do feel obliged to comment on the audiometry/graph joke.

In fact, if the test was of any use whatsoever you most certainly should have been given a graph

Human hearing is characteristically not flat - despite what any of us might think/claim.

Also, the question about age is very relevant in terms of comparison. Alas, we do not improve with age (like so many fine wines!).

BTW, I'm not suggesting for a moment you do not have good hearing, just a couple of pertinent facts .........

cheers
mark

PS: For those really serious about this, they should probably see their doctor every 6 months or so to have any extraneous wax removed .... plays havoc with the higher frequencies

[mefinnis]

I bet poor old NW never thought when he started this little gem that he would see it live to OVER 1000 POSTS !!!!!!

I'm not quite sure what that means

mark

[fcserei]

Originally posted by mrfeedback
The only amplifier in the world to challenge a theoretical limit unprecedented harmonic distortion levels of less than 1000 parts per billion
Over the past 50 years it has taken the typical audio manufacturer 50 years to reduce distortion at 20kHz from .1% to .01%. Now, with a single revolutionary technological advancement, Halcro™ has reduced distortion to less than 0.0001%. In fact, all unpleasant distortion in the output stage has been virtually eliminated.



I said exactly this sort of stuff way back in this thread, and now we have documented proof.
For you 'null testers', your amplifiers need to be as good as the Halcro to be indistiguishable, and if they are not, then the internal distortion products will be audible, and then by definition distinguishable.
0.01% amplifiers are distorted enough for the human ear to detect and categorise the distortions, especially IMD products.

I rest my case.

Eric.

Halcro, another Aussie world beater.

You only forget that the halcro distortion spec is specified with an unrealistic load. As soon as you put a real speaker to the output, the distortion of the amp-speaker combo will be about 1% second and 0.3% third harmonic distortion at 1 watt power assuming a better than average high quality speaker driver. This distortion will increase with the square law function as the power rising - so at 10W you can reach up to 100% distortion with your amp "challenging a theoretical limit ". This distortion is not a speaker distortion, rather coming from the bad speaker/amp interface. It is solely from the eddy current and thus from the volage source nature of the amp. Any amp with near 0 output impedance will produce this kind of distortion.
With a better designed speaker amp interface this distortion can be substantially reduced/ eliminated.

Remember, one of the major tweaks of the Carver challenge was to match the output impedances, to simulate similar real world distortion behaviors for the two very different amps.


Any other distortion from the magnetic and mechanical nonlinearities of the speakers will add on top of this.

[Pan]

I´mm 33 and was 31 when the test was taken. I had relatively "flat" hearing curve with a small deviation on one ear in a narrow band (dirt/vax in my ear I hope ).

The sensitivity was 10dB better across the range compared to the average test result. Don´t know if that is average for a Swede or a Human (yes Swedes are also humans ) and don´t know about age groups.

I can hear 17Hz - 20.000.Hz. Sinewaves.

Carlos,
lol

Eric,
right on and correct as usuall.

This thread is sooo fun!

Happy listening again guys

/Peter

[Pan]

"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 did the test in order to find out if there was any wrong with my hearing. I wondered this because I had health related issues that might have had something to do with the ear/hearing (balanceproblems/dizzyness).

I found out what I wanterd to know so this test was VERY useful.
I certainly did not do this test in order to brag about my "golden ears" as you seems to believe.

Jeeeez... once again!

/Peter

[Pan]

Originally posted by mrfeedback


Hi Peter,
With agieng, it is to be expected that your (our) hearing sensitivity and bandwidth degrades, however the ear/brain system is self learning, and according to aural experiences can actully become more discriminating.

The more of, and better systems that you get to experience, the bigger and better the database of 'captured' sounds you will accumulate, and become an even better judge of systems.
Also be aware that one's sonic preferences may change during this period also.

These factors are ones that our younger bretheren seem not to understand.


Eric.

Eric,

I suspect you are right as my hearing are way more sensitive now than 5 years ago. I do not suggest my actual hearing is better, but the nerve/brain function to detect/analyze/hear sounds seems indeed to be better with training (as most other human skills and functions).

I would be very curious to know the age of the participants of this thread.....

/Peter

[carlosfm]

Peter,
Congratulations, I'm 33 too!
But I'm not so sure how the human hearing can be measured.
Maby it can.
Or you listen to a particular sound, or you don't.
I'm not a specialist, but how to measure +10db inside your head?
Did you see the man doing it's job?
Or did he boost a signal by 10 db and then you heard it?
The human hearing is not at all flat.
And 20 khz seams a little high to me...
Can you hear the stereo pilot tone (19khz) on your tuner?
And if anyone says they can hear above 20khz, they may detect the "brick wall" on cd players!
Cool!

[Bane2871]

I recently stumbled across this forum. This thread was the 2nd I've read and I've found it very interesting.

There are a couple things that struck me as important and worth adding to the conversation. My interpretation of NW's post is not that all amplifiers sound the same, but that in order to eliminate any possibility of the "proud poppa" influence when auditioning equipment, a double blind and/or null test is a very good way to evaluate equipment.

The Carver test does NOT prove that all amplifiers sound the same. It only proves that a group of very experienced listeners were not able to distinguish between the amps in question("proves" isn't quite the right word, but I think many of you will understand my point). Does this mean that the electrical signals leaving the amplifiers were identical? Not necessarily. I means than any differences in the signals leaving the amplifiers did not result in an AUDIBLE difference in the sound generated by the speakers.

Does changing the type of capacitor change the characteristics of an amplifier? Probably. But is that change enough to be audible? How do you know? How do you know that the perceived difference is not do to psychological factors? Do you CARE whether or not the difference is do to psychological factors?

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.

If you are happy with the current method/paradigm/procedure you use to determine the level of quality of a particular piece of equipment. So be it. If, without any blind or null testing, amplifier A sounds better to you than amplifier B and you think the difference is worth whatever additional costs might be involved, then do it. Maybe you can genuinely hear a difference, maybe its imagined, maybe you don't care. But some people are not happy with that. Some people may want to find out if there are any AUDIBLE differences with any possible psychological effects removed. The only thing a blind test tells us is whether or not the people involved can hear a difference.

I do like the previous point made about measuring the output signal (I apologize to the person who submitted it for not properly identifying you. I don't remember who submitted the post and haven't been able to re-locate it). If a signal difference is too small to even move a driver cone, how can it possibly be audible? Which makes me wonder about the Halcro. At what level does distortion become inaudible? And does it make any sense to lower the distortion levels beyond the point at which they are already inaudible? Is the Halcro really any better if it's very impressive specs don't translate into an audible difference FOR THE PERSON DOING THE EVALUATION?

I personnally tend toward both subjective and objective evaluation. Sometimes I really don't care if a change I made would pass a double blind or null test. Other times, I would really like to know, without a doubt, that a change I made had a noticable and positive effect on the sound of my equipment.

In defence of NV, some people may have a need to make sure what they are doing will make a difference with regard to null or blind testing before they spend a tremendous amount of money. To each his own.

My $0.02.

[mikek]

Originally posted by mrfeedback
Mikek,
Your profile says things like -

Biography - asdfsffds
Interests - fdsfdsddfsad
Occupation - adrfwefd

Can you please translate that for us ?.

Eric.

bnxvcnfggffg