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Is there a noticeably audible difference between two level matched solid state amps under controlled

  • Yes... I believe a notable difference can be heard.

    Votes: 136 48.6%
  • No... I do not believe there is any audibly significant difference.

    Votes: 144 51.4%

  • Total voters
    280
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I would agree with your comments about vision. You don't have huge debates over what looks good and there is at least general agreement on the part of videophiles that THX standards are a good thing. I'd love to see studies done that quantify this, but I'm not aware of any pending research. I doubt we'll ever see a set of standards for what sounds good that the majority of audiophiles will sign on to. I would guess that hearing would come after sense of taste for variability, but it's just a guess.

That's a fact, this endless debate about amps will continue until the next ice age. :D


My friend, who has only been in the hobby for 6 years, followed all my advice except for the most important. He soundproofed and treated his room, bought a kuro plasma, Krell stereo amplifier, rotel amps to power his rears and center channel, a great subwoofer, cables, etc... etc...etc. Almost done....just needed some quality speakers to come full circle...

But he dogged my strong suggestion to buy high performance speakers, and selected his own to surprise me......a presumptuous decision on his part. ( used for 50% music, 50% blu's ). ( Once he upgraded the mains, the difference was night and day, all is good now.....the balance has been restored....and for not much more $ either )
So all things being equal, ( and in my subjective opinion ), the speaker set is the most important piece of your system. :whistling:

Have a Happy Thanksgiving fellas! Enjoy!
 

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Actually, I don't. Statistics are mathematics. Arguing against them is akin to arguing that 3+3 does not equal 6.

No it's not like 3+3=6.. That would be basic arithmetic.
Statistics is the study of the collection, analysis, interpretation, presentation, and organization of data. And the point that you've missed is the the collection of data can me easily manipulated so that when analysed, it can be interpreted in a manner that fits a particular theory

http://en.wikipedia.org/wiki/Student's_t-test

The controversy usually arises as to what is statistically significant. This can be an issue when the result is close to the threshold.

http://en.wikipedia.org/wiki/Statistical_significance

Many get a bad impression of statistics because of polls (especially political) where a small difference in the wording and change the result. Other times, people confuse statistics with forecasting which has taken on increased controversy with the global warming debate. Statistics of the type that are used in listening tests does not forecast.

Or people who use statistics as proof of cause and effect - which is a mistaken conclusion, not an indictment of statistics as a science.



I don't see any evidence to support your statement. Please provide some.
I'm not sure I follow.. I don't think I made any claims to anything.. Other than none of the articles I've read about ABX testing and amps appeared to be scientific in their methodology.

Many (but I am sure not all) ABX testing has been done under controlled conditions that are 'scientific' in their methodology. No pole driving was done nearby.
None of the articles that people link to have shown this to be the case. The pole driving was just a stretch of the imagination to make point.

In order to be an accepted study, it must be published in peer reviewed publication. Then others must be able to duplicate the results. Research generally falls apart when others are unable to obtain the same results. ABX testing with amplifiers has been reproduced repeatedly, so it stands up to scientific scrutiny.

There are many different studies available on the Internet, if you want to read them.
Here are a few scientific articles:

http://people.xiph.org/~xiphmont/demo/neil-young.html#toc_lt



Here you go. An excellent discussion one methodology used, giving you a chance to pick one apart.

http://www.bostonaudiosociety.org/bas_speaker/abx_testing2.htm

The classic study that was published in Stereo Review many years ago included all the raw data and statistical analysis. We used that as a class study. I wish I had not lost my copy.

I'm sorry.. I must have missed something.. I got that the article was about ABX testing and digital recordings. But I didn't see anything relevant to the topic at hand which is "Can we really hear a difference between amps?"

An indictment would be if ABX / blind tests always produce null results. They don't.

Sorry.. I think you've misinterpreted some of my comments. I've never said that ABX testing was invalid.
As previously stated, comments relates to the uncertainty of ABX testing in the article relating to Amps. As there isn't enough detail in to determine the scientific nature and validity.

http://idc1966.blogspot.com/2011/12/study-of-audiophile-blind-comparison.html

http://home.provide.net/~djcarlst/abx_caps.htm
comments in red.
It would appear you've spent a fair amount of time to construct your response which is very much appreciated. But I think you've taken some of the comments I've made and gone off on a bit of a tangent.
Let me be clear here.. I'm not debating the validity of ABX testing. I am merely questioning the testing methodology used in links given regarding ABX testing relating specifically to the topic at hand which which is "Can we really hear a difference between amps?"
 

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comments in red. It would appear you've spent a fair amount of time to construct your response which is very much appreciated. But I think you've taken some of the comments I've made and gone off on a bit of a tangent. Let me be clear here.. I'm not debating the validity of ABX testing. I am merely questioning the testing methodology used in links given regarding ABX testing relating specifically to the topic at hand which which is "Can we really hear a difference between amps?"

Actually, I don't. Statistics are mathematics. Arguing against them is akin to arguing that 3+3 does not equal 6.

No it's not like 3+3=6.. That would be basic arithmetic.
Statistics is the study of the collection, analysis, interpretation, presentation, and organization of data. And the point that you've missed is the the collection of data can me easily manipulated so that when analysed, it can be interpreted in a manner that fits a particular theory
If your comments are that the design of the test could be invalid, I agree with you. It is always possible to establish any test or test methodology that is invalid. One of my criticisms of ABX testing is that there are not positive nor negative controls. The closest we have to controls is that some tests produce positive results. If no ABX tests produced results, then that would be a condemnation of ABX in general.

Your definition of statistics is generally accepted. Please note that collecting the data is separate from designing and performing the test.

Statistics are the tool to analyze the data. It is impossible for two statisticians to look at the same data and calculate different conclusions (other than setting different thresholds for the null). The statistics do not lie, which was your original comment about the science of statistics.
 

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I think you have both made your points eloquently and completely, and will clearly never agree on the topic. If you have something new to present, please do, Otherwise, time to move on.
Yes, we have gotten repetitive. Unfortunately. Sorry for the taking up of space.

The title of this topic is "Can we really hear a difference between amps?"

It seems there are two groups, at least:

1) Yes. By careful listening, amps can and do sound different.

2) No. Placebo effect and double-blind / ABX testing is evidence that we cannot.

There could be a third group that I guess could loosely be defined as?:

3) Maybe, but it is subtle. Speakers and room interaction (or something else) are more important.

To discuss this topic, we must address 'the elephant in the room', double-blind / ABX testing. Is there any other way to approach this issue?

Unfortunately, as littlejohn74 and I have shown, it is difficult to discuss and make any progress. If we are unable to discuss double-blind / ABX testing, does this thread serve any purpose?
 

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Might I suggest a thread on ABX testing, its validity, how to do it properly, things like that. There are a number of us interested in the topic. And in degrees of difficulty, for instance how to do it well without having to get into all of the steps and documentation and peer review and all needed for a scientifically valid conclusion. Granted it has its need and place, but a lot can be accomplished without carrying it to that degree. Just a few thoughts.
 

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I would agree that double-blind testing is the only real test. Of course all other variables such as the room, number of people in the room, speakers and other equipment would have to be the same. Never change more than one variable at a time while testing anything.

I also think that a significant number (people familiar with statistical testing could tell us this number) of people would have to be tested to get the correct answer. Testing only a small number would probably bias the results since some already have made up their minds one way or the other even before testing.

I believe as long as both amps are well made and have about the same power, most people will not be able to tell much of a difference.

I agree that the speakers chosen for the system will make thee greatest difference in the sound. Get the best speakers you can afford first then choose the amps and pre-amps.
 

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First off, thank you for your thoughts. I love it that this topic discussion never seems to end..., as it should never end.

I agree with all of your ideas - beginning with the speaker. With a great set of (2,4,6,8 & subs??) speakers any well made amp with plenty of clean power can be adjusted to achieve a sound quality anyone could have imagined. I would only add that testing Class A and/or B tube amps (single ended or push pull topo') although may be especially satisfying comparing with a Class D and even A/B class it would be especially easy to identify which is which, even though both could be especially pleasing/satisfying when adjusted to its highest potential. Although the more popular A/B type amps compared with Class D (digital) would IMHO be a sound of very similar quality and adjustable to produce a very dynamic and satisfying sound. I don't know anything about G nor H Class amps except they are variations of the A/B type amps and are meant to minimize/overcome some of the some of the issues with A/B amplification.

One more thought on sound amplification is the Damping Factor (DF) when speaker and amp are impedance matched the amps ability or need to control speaker excursion - that is as the amplified sound ends the speaker excursion is damped to 0 motion/moment. I don't even know where to begin except to say I was always told (oh so many years ago) to look for an amp with a DF of around 200. Today IMHO because the quality of electronic parts have such low variation measurements (as low as 2% and I haven't checked in awhile) the need for Neg Feedback to control distortion is reduced in tube and solid state amps. Today I.m seeing DF's of 40 like with NAD amps and even lower etc etc.

Not to mention older tube amps were of such low power 15 watts was considered sufficient, the ability to control speaker excursion sub 100hz was impossible..., even with a very expensive 60W tube amp (especially Class A) the need to turn the power/volume up to realize low Hz numbers increases THD making it easy to detect which Class amplifier you were listening to.

Just a few thoughts - now on to the double blind placebo controlled testing..., well I don't believe anyone wants to hear about my thoughts on that.

Happy Listening and Best Regards

Greg
 

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Oh, one more thought, lol -

I wanted to suggest that any scientific comparison of amps and/or speakers must include the music of The Preservation Hall Jazz Band, but especially the one number titled "That's it" recorded live on Jimmy Fallon 13'. Even if you don't like brass bands this cut will blow your mind. Turn up the bass for that tuba duet and adjust for the snare drum ring and perfectly tuned tom-toms and floor toms - I don't know how this drummer holds the beat so fast and steady thru the whole number. Now the trumpet playing is as good as I could ever dream of and never be able to play..., for this trumpet number you better ave your socks pulled up tight and trousers bloused because he's gonna try to knock your socks off (best trumpet rendition is on YouTube under Jimmy Fallon 13' - Pres Hall Jazz Band). But here is where you will find a real test of amp and speaker dynamic - the band is amazing to me but the part I like best is when the band does a slight refrain and the trombone player does this dark and dirty blat-a-blat-blat-blat raspy grunge that will truly test the metal of any system.

This band is doing all they can or need to do to bring back/continue that NOLA Jazz Band sound. Yeah Man, the Preservation Hall Jazz Band is at the top of Jazz Band music. Their music isn't the wild Mingus style of jazz this music is tight and melodic and does things to your soul..., take a minute and listen but remember, hold onto your hat and socks cause they will take you for a ride, this is real music, you know the type of music that is so well conceived that it doesn't matter if its classic, or flamenco or folk - it grabs you and takes you to places sometimes we forget to remember, we get so caught up in life and living.

Edit: I cannot find the recording of the Live JFallon Show take..., looks like I'll have to buy it or pay to sign up for one of the sights that have it e.g. The Jimmy Fallon Show etc etc.

Happy Listening and Best Regards
Greg
 

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Hi There

I agree with all of your ideas - beginning with the speaker. With a great set of (2,4,6,8 & subs??) speakers any well made amp with plenty of clean power can be adjusted to achieve a sound quality anyone could have imagined.

Hi Gregr
May I ask what you mean by well made amp with plenty of clean power "Adjusted" to achieve a sound quality anyone could have imagined ??? So a well made Yamaha receiver of the 1980's - insert definition of clean power here - could be adjusted to achieve the sound quality of a new Levinson beast ? Is that what I am getting ? How would one adjust either unit ??

Just a few thoughts - now on to the double blind placebo controlled testing..., well I don't believe anyone wants to hear about my thoughts on that.

Does not work, never has, or there would be at least some differing results. Double blind aids in masking any meaningful differences. This may be why double blind was used in firing squads or hangings, you can never see what's coming,

Happy Listening and Best Regards

Greg
 

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Yeah - even if your in a bad space..., you gotta get something outa' that.

Ya know I got so caught up in writing I forgot to notice - the drummer only uses the single floor-tom and kick bass - he still gets my vote.

FYI - the KEXP session is amazing music to my ears but there is one better IMHO it is the Jimmy Fallon Showing. You'll know it when you see the-or-an audience on stage with the PHJB and the dance floor is filled with professional break and popping dancers. The trumpet player does not miss a note or a beat. But it seems unless you subscribe to JF site and recording medium playback etc etc

Happy Listening and Best Regards
 

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Hi Jack,
Glad to see you and Tonto are still carrying the torch for humanity, music and theater. In these next few lines if I say anything that sounds off color or crass..., don't believe it, Please. I too, like most who like to write/talk and carry on about all of the above and as much as I attempt to write clearly with ample detail there are times when I fail.

When I wrote about clean power: I was imagining a clean circuit beginingwhere my 220v line seperates from a transfer station and traveles down to my house then is split through at the breaker box and routed through the house to a dedicated Audio system outlet and video system outlet. I'll just add - I'd love to try one of PS Audio' regeneration power stations for audio and video but for now my Monster HTS 3600 MKII will have to do...., and I'm not complaining. Next, paying close attention to cable routing/grounding issues minimizing electromagnetic field interactions (which I have not done to this day - maybe that's my first invention). I do use double shielded power cables, interconnects and a large ferrite at the speaker end of my Kimber Kables. Next clean/uninterrupted power through the speaker crossover and out to the voice coil windings.
I would add IMHO, I take every opportunity to buy the purest copper cables of highest electrical integrity - meaning all of the cables I use have an average resistance of 7-10 Ohms fer Kilometer.

As for the Double-Blind Placebo controlled study - I, you or any single individual can perform one - keeping in mind to watch for "first bias" "attitudinal bias" or simple prejudice e.g. transference/counter-transference's of personal nature and the desire to please.... However the real scientific study does not end here. Next is to design a research question/with questionnaire (containing only numerical values) for statistical analysis - after that it is endless listening. Two hours per day I believe would be minimal, thereby allowing the cabling and electronics to fully energize and function at its peak. Oh yes you can accomplish the same using a group of people as well. Next, for a more reliable correlational "solution for P" the higher the number of trials must be achieved.

Its a monumental task ..., but it can be done. Then, this is where science really begins - because if you write the scientific question and use 10 numerical variables and repeat the test for seven days..., one day somebody will use 20 variables and study for 14 days and if this most recent study seems to validate your study you can begin the simple task of graphing each study "solution for P" and with each increase in variable and study length you should find each solution plot a straight line on a graph. Otherwise there may be an error in the study question or variable or the DBPC study perimeters.
Sounds like fun to me... not

sorry I didn't proof read - I wish I had, but you can see what is generally required -its late

Happy Listening and Best Regards
 

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LOL.
When this thread gets the tires kicked you just never know what kind of "new" information will get posted.
Hopefully the most recent responders here have also found the amplifier comparison thread that was posted a month or so ago.
 

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Hi Jack,
Glad to see you and Tonto are still carrying the torch for humanity, music and theater. In these next few lines if I say anything that sounds off color or crass..., don't believe it, Please. I too, like most who like to write/talk and carry on about all of the above and as much as I attempt to write clearly with ample detail there are times when I fail.

When I wrote about clean power: I was imagining a clean circuit beginingwhere my 220v line seperates from a transfer station and traveles down to my house then is split through at the breaker box and routed through the house to a dedicated Audio system outlet and video system outlet. I'll just add - I'd love to try one of PS Audio' regeneration power stations for audio and video but for now my Monster HTS 3600 MKII will have to do...., and I'm not complaining. Next, paying close attention to cable routing/grounding issues minimizing electromagnetic field interactions (which I have not done to this day - maybe that's my first invention). I do use double shielded power cables, interconnects and a large ferrite at the speaker end of my Kimber Kables. Next clean/uninterrupted power through the speaker crossover and out to the voice coil windings.
I would add IMHO, I take every opportunity to buy the purest copper cables of highest electrical integrity - meaning all of the cables I use have an average resistance of 7-10 Ohms fer Kilometer.

As for the Double-Blind Placebo controlled study - I, you or any single individual can perform one - keeping in mind to watch for "first bias" "attitudinal bias" or simple prejudice e.g. transference/counter-transference's of personal nature and the desire to please.... However the real scientific study does not end here. Next is to design a research question/with questionnaire (containing only numerical values) for statistical analysis - after that it is endless listening. Two hours per day I believe would be minimal, thereby allowing the cabling and electronics to fully energize and function at its peak. Oh yes you can accomplish the same using a group of people as well. Next, for a more reliable correlational "solution for P" the higher the number of trials must be achieved.

Its a monumental task ..., but it can be done. Then, this is where science really begins - because if you write the scientific question and use 10 numerical variables and repeat the test for seven days..., one day somebody will use 20 variables and study for 14 days and if this most recent study seems to validate your study you can begin the simple task of graphing each study "solution for P" and with each increase in variable and study length you should find each solution plot a straight line on a graph. Otherwise there may be an error in the study question or variable or the DBPC study perimeters.
Sounds like fun to me... not

sorry I didn't proof read - I wish I had, but you can see what is generally required -its late

Happy Listening and Best Regards
Hi Greg and Thank You for your post, it makes me smile that someone is willing to debate sensibly on this tense matter. Have you noticed that the poll goes up or down by a few persons depending on which audio nut posted last, be it positive or negative ?? Cool.

I also want to thank you for thinking Tonto and I are keeping up the challenge so to speak when in fact there are hundreds of folks on either side of the fence that have just given up LOL, they can only take so much.

To your first point, I do understand, we all have that issue to some extent. Like you I do not have a regeneration station but merely a large power filter most things plug into so from that point most of us are equal. Getting a good clean amount of electricity into the equipment is a grand idea, and that means all the equipment, however, some items have built in filters and what have you right in the power supply architecture. My Emotiva amps do not recommend that they be plugged into anything but the wall as they draw a significant amount of current and have those filters built in. I am not sure it matters one way or the other as I do my testing with the amps plugged into the wall. All other equipment is plugged into the power supply filter thingie. So with the clean power not always available but lets agree that all amps being tested are plugged into the same source, we should have theoretically an even base to start with. No advantages to a receiver or a monster current user.

Ok on to point two. I personally have no desire to enter into a blind test or as you say placebo test as they have been done so many times and with a very high percentage of reaching the same conclusion. No reason to go over them any more as to me they appear more methodical then scientific. I believe that there are no tests presently available that can fully recreate what we as individual humans perceive in our ear brain interface. BlueLou reminded me this weekend that there has been a panel conducted by Harmon Labs that uses numerous personnel and equipment to try and work out a generally perceived and subjective finding of a good system to the most of the masses, however, even with the greatest of mathematical equations, this can only tell us what tends to sound good. The trouble further down the line is that as humans we do not hear the same and there are no proper measurements for what we as individuals cherish in our sound reproduction. I dont like nasty highs but someone who is maybe loosing their hearing in that range of frequency would disagree and say, maybe those highs I find nasty are the pudding in his or her cake. You know the one mans ceiling is another mans floor. Further, there are no tests for sound staging in a music system. How deep and wide, high or low is a human thing born of tens of thousands of years of evolution if you believe in that sort of thing. Lastly, what is important to an individual listener, dynamics, delicacy, slam, bass, midrange, treble, female vocals, male vocals, orchesta music, rock, pop, jazz and on and on. Some folks love the ability to move walls with bottom end etc.

In my opinion the above is WHY amps sound different from one another and when one combines their sonic preferences with their pocket books, voila, we get enjoyment. If all amps sounded the same, there would be no reason to have so many types and brands. It would be scientifically inconceivable to think that the design, implementation and quality of the components within an amplifier have no affect. It seems that one cannot ask the question, "Do All Amplifiers Sound The Same" without a good number of conditional variances being placed into the mix. An Amplifier amplifies and that is where we need to hang our hats. If too many conditions are applied than the question must be changed. By adding conditions, we are forcing all of the amps into a similar place where good ones and less than good ones may be the same. That imo is not proper. And yes, an AVR has an ampifier in it and as such works as an amp and preamp all in one box, where as separate basic amps need an outside preamp. Integrated amps really work well too without all of the other electricity sucking options most AVRs have.

As such, I feel that a middle of the road AVR and an outstanding Basic amp/preamp combination need to be tested equally. If any version does not work then it is not acceptable and by that I mean if it does not sound good or if if it cannot make music for any reason, they ohh ohhh it needs to go.

Lastly I think more folks probably need to hear as much live music as possible to be able to detect all of the nuances made above. Without that basic knowledge, there can be no room for a proper investigation, imo of course. :eek:lddude: This evolution of discovery takes a great deal of time....on occasion and takes patience.
 

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Not sure how to vote... I think there are differences in amps whether it is by design or quality of parts. How much of a difference? As soon as Audyssey or Dirac is brought into the equation though I think it gets real hard to hear any difference at all.
 

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Hi Jack - Your right there are many people here who do keep keep this site alive and down to earth. I started looking for the amp discussion yesterday and was real happy to see the advertising is still well out of the way. Lots of great topics as usual including this one "Can we HEAR the difference"

Thank you for your thoughtful experienced and considered thoughts. I have a feeling You and I and probably 80% of the people voting know already that this discussion probably will never be resolved to an agreeable solution, that is at 100%, could it ever be 100% we are discussing humans and individual senses. You know when Sonnie first refreshed this question I felt I knew his reason, its a great question. I only wish there was an real answer but the discussion "ahhh, the discussion" it really makes me wonder.

However if you were to hear from a statistician and audiophile he/she might declare from oh but of course to within a degree of certainty... and so on. But what about an artist - even Monet might declare his frustration with the public, "people are so fickle..., there is no pleasing them."(my imagination not Monet' words).

I did start thinking of a simple questionnaire (in case somebody did ask)..., but the further along I got I stopped quick with a thought - what if after years of statistical analysis it is discovered we've been asking the wrong question. What if the research question is actually "___________". What if hearing is like color blindness and every other human anomaly and everybody listens and hears differently.

Consider for a moment a survey questionnaire of this type:
Question 1. Did you hear the Cymbals
Answer 1. Not really, no
2. a little/from time to time
3. Yes clearly

Question 2. Did your hear the keyboards - Piano/organ
Answer 2.

...same answers as above.

Then I thought well wait a minute, I can't listen for all of the instruments and answer these questions at the same time (continue with me for another moment) - I don't hear music like that... the best I can do is develop a ghostly quiet background so that well recorded music has every opp to bloom and send out every tenuous tendril of sound that sparkles and shimmers and continue endlessly in my mind. You know what I mean. I know you all do.

I'm getting older and the I know my upper listening ability is fading. I believe this is why I am so obsessed with the sound of the cymbals in the music I listen to. From the ring of the cymbal crown and gong sound of the crash cymbals and the sizzle of the riveted ride cymbals and one day..., only when I stop to wonder and remember will I truly miss anything at all.

Because I believe I see (for myself at least) I do listen for the cymbals but I also listen for the lead guitar and I listen for the keyboards etc etc etc etc BUT what I hear is everything. I hear individual instruments, but what is music? Its all of the above and the harmonies and all those dancing tendrils of sound and the space between the notes "ahhh Sigmund, its the spaces between the notes that thrill to the core of my being" That ghostly quiet that speaks to me..., OK I might have over done this a bit but its been one of those days.

If when I am finally very old (whatever that means) and all I can hear for sound is the sound of Mr Wailing Jennings old raspy voice over a little slide guitar pickin' that'al be just fine with me too.

I don't wonder why we all get so excited about this topic... I feel like I'm forgetting to fully answer your response Jack but I'll have to check back to be sure I have treated you with the utmost respect I do believe you've earned and deserve.

Happy Listening and Best Regards
 

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Well, the question is never going to have a one size fits all answer. But what we can say is that it is very hard to identify differences reliably among decent quality amps. The methodology of testing is quite difficult and many oversimplify the concept of AB or ABX testing.

The conclusion that I come to after more than 35 years in the business and listening to more different products than most people, and more live performance than most, is that differences in amps are rarely significant. However, I do not discount the possibility that they exist and the only fair way to address the question is to do our best to identify differences if the do exist. I go into comparisons with the assumption that I will be able to hear differences and try to document what they are. If they can be identified consistently, I think we can agree that they are real. I have yet to be statistically successful in identifying differences. I have had some consistency across blind comparisons, but not enough to reach statistical significance. Maybe with more trials and more control of variables like distractions and listening time....
 
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