Audio Blind Testing

[gmgraves]

7 hours ago, Speedskater said:

A problem with blind testing is that they try to do a big test with many listeners and many repetitions. They should start with a very small informal test. That would be one interested audiophile, where he chooses the music, the volume and the sample time. If he can't easily hear a difference then there's no reason to expand the test.

 

Actually, I think that you do need a fairly large participant pool. What we hear, and to what we attribute what we hear, is largely predicated on such variables as how we feel at that particular time, our familiarity with the sound source (audio system, room) and whether or not we are tuned to hear the differences that are being investigated by the test. The idea of the "golden-eared audiophile" is no myth. While we don't actually have hearing that is more acute than that of the average joe, we have trained ourselves to be sensitive to characteristics in reproduced music that your average Joe neither knows or cares about. Many such things most people won't even notice. OTOH, different audiophiles tend to focus their critical sensibilities upon those characteristics that particularly interest them. Some focus on soundstage, and don't particularly care whether or not their audio system has ruler-flat frequency response, while another might be very sensitive to even small changes in perceived distortion. In order to statistically level the "listening field" it is necessary, in my opinion, to incorporate a number of different listeners and to use written private ballots to register whether or not differences were heard in each individual trial.

IOW, just because I don't hear a particular difference, don't mean that you won't hear it either. 

[gmgraves]

1 hour ago, Kal Rubinson said:

 

I agree.  How is the "one interested audiophile" selected and qualified?  The whole significance of statistical assessment is to not rely on any single anecdote.

 

Absolutely. There must be some consensus of opinion on differences heard, and how can there be a consensus of one? 

[gmgraves]

3 hours ago, GUTB said:

 

 

 

4 hours ago, GUTB said:

I have nothing to add to the topic of audio blind testing -- except to say that it won't work unless there are very large differences in sound. Not to any degree of acceptable mathematical rigor, anyway. This is due to the ear-brain issues that are difficult to control for.

 

I just wanted to post that whenever I see "audio blind testing" I want to read it as "audio bling testing", which would be a much more entertaining thread.

 

One again GUTB exhibits a profound ignorance of the subject being discussed. It has been proven beyond a doubt that double-blind testing (where no one, not the assembled listeners, and not the people performing the test have any idea of which device under test is being played at any given instant) is the only way to reliably hear differences in components. when nobody knows, other than by a designation such as "A" or "B" or "1" or "2" what they are listening to. This absolutely removes from the listening equation any sighted or expectational bias. IOW, you won't pick your new $800/pair interconnects as sounding better simply because you just paid $800 for them! Believe me that kind of thinking colors any other kind of evaluation. Many would include ABX testing in this, but I don't simply because nobody has been able to ever convince me that the ABX comparator doesn't color the results. The only way is to manually swap out those devices under test.

[gmgraves]

15 hours ago, sandyk said:

  I agree.

The only way is to have somebody else not connected with the listening decisions part, to manually swap out the devices under test behind the scenes.

 

And of course, that person shouldn't know which device is being "hooked-up" any more than the listeners shotld. Otherwise it's not a true DBT.

 

The co-inventor (with Ben Muller) of the ABX comparator, one Arny Krueger,  invented the thing (by his own admission) in order to prove that everything (except speakers) sounded the same. This is a point that he argued on Usenet for years against me and others (and notoriously against John Atkinson in a famous, public debate). After debating with his nonsense for years about amplifiers, DACs, disc players and vinyl setups, I came to the conclusion that he couldn't hear. He made so many ridiculous assertions, that as far as I'm concerned, the man has no credibility whatsoever!  Some of his assertions were: the original Dynaco Stereo 120 Solid-State amplifier from the 1960s sounded exactly like the then latest Amps from Krell, Pass, Audio Research, etc. This was at a time when it common knowledge that anyone could see (and ostensibly hear) the nasty crossover notch from a sine wave on the oscilloscope caused by the 2N3055 output transistors on the ST120 being too slow to switch fast enough and too fragile to be biased far enough into class AB to eliminate the notch. The amp sounded awful and was only tolerated by the audiophile public because it was cheap, and powerful (for the day) and the audio press was touting the "transistor sound" as being a good thing! He also asserted that the (then) latest $100 Japanese receivers from Costco sounded exactly like "so-called high-end amplifiers" costing upwards of one-hundred times as much! He also maintained that he was still using the original Sony CDP-101 player from 1982, and that it sounded just exactly like the latest high-end players from MSB, dcS, etc. and that they were a rip-off! Another of Krueger's classic idiotic assertions was that the latest turntable/arm/cartridges were no better than those of the 1960's and that absolutely no progress had been made in that field! While it is true that some decks from those days can still be satisfying performers when restored (Garrard 301, 401, Thorens TD-124, TD 125, the AR turntable (sans arm), etc), arms and cartridges and decks have improved in leaps and bounds. I've had turntables from the '60's, '70's, '80's  up to the present, and I can tell that the best vinyl rigs of today will knock the sox off of the best that any 20th century playback rig had to offer (not to say that these older decks can't sound good, but they simply cannot retrieve from the grooves the level of SQ that today's best vinyl rigs can. It's an eye-opening experience to hear what even old LPs can sound like on a state-of-the-art rig from Walker, VPI, or Air Force or Clearaudio (to name a few)!

My point is how can an ABX comparator designer like Krueger make a totally transparent comparator when he can't hear the difference between transparent and non-transparent or the differences between the equipment likely to be tested by it? 

[gmgraves]

15 hours ago, GUTB said:

. @gmgraves admits to have faced it himself, but he chooses to believe the differences he heard were in his head after being influenced by the stress of blind testing.

 

Actually, I came to the conclusion that these interconnect cable differences were imaginary after they disappeared in DBT after DBT. It was then that I realized what a strong influence expectational and conformational bias plays on the human brain. Senses are easily corruptible and can only be trusted to a certain degree (one example of trustable opinions is those that result from long-term listening over many different times of day, and different moods). The truth is that people see and hear what they expect to see and hear and often what they want (consciously or subconsciously) to see and hear. Criminal science has decided that no evidence in a court of law is more unreliable than the well-meaning eye-witness. Unfortunately, the court systems (at least in the USA) have yet to evolve to the point where eye-witness testimony is accorded the diminished weight it deserves in an actual trial. 

[gmgraves]

11 hours ago, fas42 said:

 

Things like interconnect cable differences will always fail in DBT - that's because the time factor aspect is never part of the test - first rule of science: always make sure you are really testing what you think you are attempting to verify, rather than doing a show off demo of the fact that you can play "scientist in a lab coat".

 

Cabling behaviour varies over time - because of material considerations - there are all sorts of subtleties involved here, which matter when the best in reproduction is being aimed for. Claiming that this sort of thing doesn't exist, "because it shouldn't !! ", is not very helpful ...

You're right. Interconnect differences will always fail a DBT because they don't exist. When someone switches between a cheap Radio Shack cable and an expensive interconnect from the likes of Kimber or AudioQuest, etc. and nobody in the room notices even the slightest or subtlest difference or can even tell that there has been a switch, then it must be because there is no difference. Going off half cocked looking for metaphysical reasons why something as simple as an audio cable "fails" a DBT, isn't very helpful either.

[gmgraves]

9 hours ago, Ralf11 said:

I've heard people claim that different masterings are often used for the Redbook layer on SACDs - anybody know for sure?

 

It seems like an odd thing for a recording co. to do...

It's true. I asked Paul Stubblebine that exact question, and he said that as often as not, the CD layer comes from an earlier Red Book master.

[gmgraves]

3 hours ago, STC said:

 

Are you referring to rec.audio-high end newsgroup? I vaguely remember the "debate" which got him banned from the group before readmitting him after about year.

 

Arny never claimed that everything sounded alike. The blind test data clearly showed a difference between Dyna400 and a tube amplfier. Even the Sony and Philips CD players sounded different under blind testing. 

I am referring to rec.audio-high end. And the Arny Krueger that I remember, argued most vociferously that everything sounded the same when I was contributing to that group. After I left, I don't know what might have transpired. 

[gmgraves]

12 hours ago, sandyk said:

 George

 I thought that you had got well past these dogmatic assertions  about Interconnects, but apparently not.

Interconnects of the same length , but of different construction can sound quite different due to differences in capacitance, immunity to RF/EMI  etc. A Blue Jeans LC1 for example , with just over half the capacitance of many other interconnects can sound quite different to a typical coaxial construction type cable of the same length due to interactions with the output stage of the DAC, Preamp etc.  Many commonly used I.C.s used in consumer gear output stages do not like driving higher capacitance loads, and can even become unstable when driving higher than average cable capacitance and often use series output resistors of typically 100 ohms to help prevent this.

The LM4562 for example, is quite fussy in this respect.

Alex

 

P.S.

This is starting to sound a bit like Groundhog Day !

I don't want to start this again, but with your knowledge of electronics, I'm sure you know that differences in capacitances, Inductances etc.; while they can have an effect at very high (essentially RF) frequencies, don't affect audio frequencies at all except in very long runs of 50 ft or more. (where RG 59U is down 1 dB at 20 KHz, IIRC)

While what you say about modern op-amps may be true (I don't claim to have the practical working knowledge of op-amps that you do), I have not encountered that phenomenon. Obviously what you are saying is that when driving high reactance loads (such as a cable with high capacitance) an op-amp's frequency response will be altered or the op-amp could become unstable (go into oscillation?).  OK, I can see that. IOW, it's not the cable per se that is changing the sound, but rather the cable's characteristics affecting the output stage of the component driving the cable? Well, that's reasonable. However, audio is such a low frequency signal that I still have difficulty, not with the concept, but with the degree with which this phenomenon can affect such a signal. Were we talking 100 MHz or greater, I'd say that yes, the conducting cable's reactivity is very important to delivering a signal from one component to another in such a way that it is delivered as intact as possible. But I've run all kinds of audio frequency signals; sine waves, square waves, triangular waves, pulse waves of varying duty cycle, etc. through all kinds of cable, and they all look the same at any frequency from just a few Hertz to at least 1 MHz.

But that's not the issue here. 

This is a discussion of blind testing. Fas42 asserted that cables will always fail a DBT and quoted some dubious technical reasons for this. My response (a little heavy handed, perhaps) was that when things (in this case cables) fail to show a difference in a DBT, it's because there is no difference to show. Perhaps I should have taken a somewhat lighter approach and merely said something like "Are you saying that the only time that different cables are audibly different is when you are looking at them?" Sarcastic yes, but perhaps it wouldn't have opened old wounds here. 

I have, to my satisfaction, proven two things to myself. 1) Generally, with something really simple like interconnect cables (passive component, easy to switch in and out of a test), DBTs show the truth and 2) more complex components like amplifiers, DACs, etc., can show that a difference between two makes/models does exist, but that it takes long term listening to characterize and quantify those differences. But there is a big caveat here. Since interconnect cables (I do not include speaker cables in this discussion. They're a different kettle of fish.) are passive, and short, there is no chance for a level difference between them to exist (as long as they are JUST cables and don't have other components in them); I.E. there should be no insertion loss. That makes it a certainty that switching between two cables will not result in a loudness discrepancy. So if one hears a difference when the two cables under test are instantaneously switched, then a difference between those cables definitely exists. If numerous tries and numerous different interconnect sets are tried against each other at different times and in different places and no discernible difference in sound is detected, then I think it's reasonable to conclude that no difference in sound exists between the tested interconnect cables.

With active components, it's different. There are so many variables, and it's so easy to get a mismatch in level between two DUTs (even 1 dB can be enough to invalidate the test) that in my opinion, one is better off skipping the DBT altogether and going with long term comparisons while taking lots of notes! 

In the post to which you reference, I stated the fact that in a number of different DBT "cable shoot-outs" to which I've been party, Instantaneous switching between cables has concluded in a result where not only has no one participating been able to hear any discernible difference, they couldn't even tell when or if the cables had been switched. That's my experience, and I'm content that interconnect cables aren't worth my time. Others might see it differently, that's up to them. But in the context of this thread, I feel that my comments were on subject and germane to the topic of DBTs. And no, I don't wish to visit the interconnect question as a subject for debate again. To me it's a question asked and answered.

[gmgraves]

18 minutes ago, fas42 said:

 

Ah, dear ... you've answered your own "questions" - it's the "long term" consideration aspect, you see ...

 

Which is the only way to make decisions ... there's a concept which is an inconvenient truth in audio, being, that qualities change over time, for a myriad of reasons. And no matter how hard one wants to pretend that a plugged in cable, as a piece of an electrical circuit puzzle, is 100% passive - whatever that means - the reality is otherwise. A genuine, engineering solution is to make all the electricals fit in one box - no more cable nonsense! - but then we wouldn't have the fun of trying a Chrysler engine in a Ford body, with a GM suspension - surely that's gotta be better than a car done by a single engineering team ... .

 

No, my results have answered my questions, not I. And if things change over time, then they change over time, but if you can't notice or measure the changes, what difference does it make?  I mean it's a lot like the classic dilemma; "If a tree falls in the forest, and there is nobody (and nothing) around hear it fall, does it make any sound?" The answer, is of course, that it doesn't matter and neither does this.  

[gmgraves]

8 minutes ago, sandyk said:

Based on my personal experiences with the music track of the .wav file waveform that I attached, I do NOT agree with you, and neither do a large number of members agree with you about the audible differences between different Interconnects.

 

And that's fine.

9 minutes ago, sandyk said:

There is obviously far more to it than just Attenuation with Frequency, there is also rejection of RF/EMI etc. and the resistivity of the Earth side in  particular does matter when it is part of the reference Earth for the system.

 That may be, but if I can't hear it under controlled circumstances, it doesn't matter to me (but that doesn't mean that I wouldn't like to know what the mechanism is - I would dearly like to know!). 

 

12 minutes ago, sandyk said:

Neither can I explain the audible differences that I hear between 2 75 ohm 1.5M cables that I use for Coax SPDIF.

Recently, one of the RCA plugs became a little loose in the socket of my Soundcard, so I replaced it. What did surprise me was that unlike many, it had 2 layers of braiding as well as aluminium foil, and immediately struck me as better made.

 Did you see my comment about short D.C.  cables discussed in the Uptone area of the forum where E.E. John Swenson describes a technical and audible improvement for even short D.C. cables ?

 These guys are hearing confirmed differences that I wouldn't have believed possible either.

 

And if I had ever been able to confirm some of the differences I have heard, over the years, wrt interconnects, I'd be in your camp too. But I haven't and I dare say that the people who have been in the same room with me when DBTs showed no differences, would agree with me (they're not the same people in each DBT, BTW). I believe in buying quality cables, and I do. But that's construction quality, not SQ. 

[gmgraves]

1 minute ago, sandyk said:

 I have already answered some of these things in my reply to George.

A Zip cord for example has very little RF/EMI rejection.

 

What if RF/EMI isn't a problem in one's specific situation? A guy I once knew made up a pair of "interconnects" using 12 Gauge speaker wire and asked me to try them out. I did so between my then Audio Research SP11 and my VTL 140 mono-blocs. I heard no increase in noise or any hum (I was careful to dress the interconnects away from any mains leads). I can see situations where RFI and EMI is a problem and in such a case one should not use un-shielded cable, and one should probably think about going balanced!  

[gmgraves]

55 minutes ago, sandyk said:

 That was exactly the case with this Coax SPDIF cable. It was a more expensive replacement for an older cable that had become poor fitting due to being moved around numerous times over the years, with PC moves to different addresses and PC upgrades.

 I certainly did NOT expect to hear any difference between functioning Coax SPDIF cable of a similar length, any more than I expected to hear a difference between a proper INSULATED 75 ohm BNC socket on my DAC and a generic, less well constructed 50 ohm version which people like yourself claim can't possibly make any difference in such a short length.

Then we're essentially on the same page. End of debate.

[gmgraves]

51 minutes ago, sandyk said:

 George

Several years ago I moved a Class A Preamp PCB to another area of the room with the DMM still connected across it's output, as I had been checking D.C. offset. I was very surprised to see quite a few mV being read at it's output with NO power connected. It was due to RF pickup, possibly from a not too distant FM Stereo transmitter.

Not all RF/EMI results in audible hum, but it can still degrade S/N performance.

 Alex

I'm aware of that, that's why I said that heard no increase in hum OR NOISE. Of course it's a case by case thing. My circumstances may be quite different from yours and my circumstances now at my present location might be completely different from where I was when I tried the unshielded cables. I might get an entirely different result here, but I'm not about to try unshielded cables at this point.

[gmgraves]

3 minutes ago, sandyk said:

NO !

 I heard differences that I didn't expect to hear, and that you believe are NOT possible. 

 

Whatever. It's not worth debating about and certainly not worth getting angry over. 

[gmgraves]

16 minutes ago, GUTB said:

I feel like mailing @gmgraves a set of my Audio Sensibility Statement XLRs (7N OCC, Teflon, cotton, Furutech) to challenge this belief system.

 

I had installed a new audio stand against a sidewall to reduce distortion caused by putting equipment between my speakers. In order for the pre to reach the amps I used a set of cheap 5 meter interconnects I had laying around. I ended up moving the rack back to the front of the room because I couldn’t stand how badly the sound was impacted. I then tried comparing the cheap interconnects with my Statements to find that yes, the cheap cables caused the soundstage to narrow and lead to a sense of congestion and muddied sound — a big downgrade. 

 

Here’s the twist — the cheap cables weren’t cheap at all. Looking more closely, I noticed they were Belden with Neutrik connectors. 

 

 

Wouldn't do any good. the only thing I have that uses XLRs is my recording equipment. 

[gmgraves]

10 hours ago, fas42 said:

 

Things changing over time are very, very important to me ... because the first time I experienced a step jump in subjective quality of playback, demonstrating what was possible, a huge frustration was that this major difference in the subjective presentation was very fragile - it would vanish like the morning mist, as I was listening - over and over again. I could not get an upper hand on this behaviour at the time, but it made me enormously aware that the slightest "imperfection" in the setup could be enough to degrade key areas of integrity - which I've spent years tackling, on and off.

 

If I understand correctly what you are saying, I see people making this claim all the time, and frankly as a many year owner of tube gear, I don't buy it.  People cannot detect gradual changes in an audio system's sound (an analogy is the frog in the pot of heating water). Many's the time I have been astounded at the difference when changing-out older tubes in an audio system. I never noticed the gradual deterioration of SQ until I changed tubes, and then the difference was considerable and immediately noticeable. Also, human beings have no long-term memory for sound quality either. So when I hear people talk about how their components "burn-in" over many weeks or months, I look upon that statement with jaundiced eye, because nobody can possibly remember what something sounded like weeks or months before. If one insists that they can, then I say that person is either delusional or a liar. 

 

Quote

 

It is entirely possible that a system may be so capable in every other way that a non-optimised interconnect won't be audibly significant - but I haven't come across such a situation yet. When a majority of systems can produce competent sound, without taking special care, then the relative importance of such things will be easier to determine.

 

Can you please explain what a "non-optimized interconnect", and how does one know that they have found an "optimized" one? There are thousands of interconnect brands and models out there. How does one know that the interconnect that they just bought is "optimized" over the thousands of other choices of interconnects that they could have bought?

[gmgraves]

3 hours ago, sandyk said:

 Up until that point I was in agreement with you about slow degradation not being noticeable, but I don't use Tube amplifiers, and semiconductor amplifiers don't slowly degrade in SQ unless due to something like electrolytic capacitors in the PSU drying  out . That is why these days I often check PSU electros for domed tops and signs of leakage.

This became more necessary due to the Pirated electrolyte episode that helped to destroy so many PC Motherboards.

 

My word, Alex! My point had little to do with tube amplifiers, I was just using those to illustrate how performance can degrade slowly over time and we not notice the degradation until we remedy it. I'm surprised that you didn't pick up on the fact that the tube anecdote was just an example of that phenomenon. I use only solid-state these days myself.

 

3 hours ago, sandyk said:

I rely heavily on the depth of image and listen for a 3D type presentation with good source material for equipment evaluation after modifications etc., mainly using headphones for this.  I DO notice if this aspect is as good as it was even a year earlier when doing this. If it isn't, I check my B.P. before digging deeper into it.

Perhaps I am a LIAR ???

 

I seriously doubt that you are a liar. All psychoacousticians agree that human memory of how something in a musical performance sounds is extremely short (strangely though, this does not apply to voices. We recognize voices that are familiar to us almost instantly and we never forget them. This is tied to some primordial survival skill). Oh, you can concentrate on one aspect of the sound and remember it as a general impression, but not in fact. What I mean by that is something like: "I went to the symphony last night and I couldn't get over how smooth the strings sounded." Now you will remember your impression of the strings, but you won't be able to remember what the strings actually sounded like, just your reaction to what they sounded like. In your case you have a mental impression of some aspect of past imaging, and you are comparing that to a current impression of imaging, but here's the rub. Your remembered impression of anything really specific, might be inaccurate. Specific impressions are very subject to the vagaries of human memory. An excellent example of this is the eye witness to a crime who is sure that he saw the defendant commit the crime, and is later found out to have fingered the wrong man. A lot of research has been done in this field recently. It turns out that memory in humans doesn't work like a recording (which was supposed for decades), that is to say, it's not continuous. The brain "refreshes" the memory every time it is brought to consciousness. IOW, it recalls it and refiles or 're-writes" it. When this happens, all kinds of non associative forces creep into it changing it subtly. Not saying that this is happening in your example, but it's possible simply because you are human. 

 

[gmgraves]

3 hours ago, fas42 said:

The interconnect should have the electrical characteristics of a short, soldered link or track on a circuit board - anything less than that could cause audible issues.

 

Well, that definition fits any properly made shielded cable of less than 10 ft in length; meaning that at audio frequencies, there is no measurable or visible (as on an oscilloscope) difference between a signal at one end of a soldered link or printed circuit track or one end to the other of a short, audiophile "length" (18" - 2 meters) of coax terminated in RCA plugs! A cheap Radio Shack interconnect meets those standards.  

3 hours ago, fas42 said:

The technique I use is single core wire, shielded as best as possible, no longer than necessary, and soldered directly to the appropriate circuit nodes at either end - the connection has lost the properties of a plug-in cable, and everything benefits. Of course, this option is not open to most people - and this is something the audio industry needs to address.

 

If you are saying that RCA connectors suck, you won't get any argument from me. How this connector made the jump from a connector invented by RCA Victor in the mid-forties to transfer the IF signal from the tuner of an RCA model 4630 TV (the first commercial post WWII TV set) to the first IF amplifier on the main chassis, to the ubiquitous universal Hi-Fi interconnect connector, is beyond me! It's designed wrong (make hot before ground [earth] and break ground before hot???!!! This is an invitation to blown speakers and even damaged components!), in it's simplest form it is unreliable (it was designed to connected once and not touched again unless the TV tuner needed maintenance), and seldom makes a gas-tight connection. The earliest use as an audio connector that I've ever seen was in a 1949 RCA Victor console TV that my family had when I was a child. On the back of the TV was a single RCA jack marked "auxiliary audio". The set itself was a "console" model with a 12-inch woofer and a 2-inch cone "tweeter" mounted inside of an unfinished plywood bass reflex cabinet, sitting on three springs inside the bottom part (chassis in the top) of the furniture cabinet. The chassis had an 8-10 watt amplifier on-board using a pair of 6V6 output tubes in the push-pull "Williamson" circuit configuration. To invoke this rear-mounted RCA jack, one pulled the on/off/volume knob toward one. Normally, to watch TV  you rotated the control clockwise to power the TV and control the volume. Pulling the control instead of rotating it left the TV circuitry off and the screen blank and allowed you to control the volume normally. Around 1953, my dad built an early Heathkit FM tuner and that sat on top of the TV console and played through the RCA jack on the back. To my young ears, it sounded pretty good too! When we replaced the TV with our first color set in about 1958, the "auxiliary audio" jack was lost and the FM tuner fell to me and my nascent Hi-Fi enthusiasm.  

 

[gmgraves]

2 minutes ago, fas42 said:

 

It's a huge weak link ... the only solution is to completely bypass it; the first thing I do when optimising a setup. Otherwise, I might as well try driving a Ferrari with flat tyres ...

 

That may be just a wee bit of hyperbole, but I get your gist! A Ferrari with flat tires..... I'd rather see a church fall down! 

[gmgraves]

21 minutes ago, fas42 said:

 

Which is why I have not the slightest interest in what a "system sounds like" - this is irrelevant. What matters is whether elements of recordings that I know well are reproduced without obvious problems, and virtually all systems I casually come across fail by this test - it's defective behaviour of the playback chain that's audible, that needs to be addressed; which automatically leads to optimum reproduction of all one's recordings.

 

I'm sorry, I'm having a bit of trouble following this line of reasoning. If it isn't about what a system "sounds like", then what is it about? I mean, if recordings are "reproduced without obvious problems" then isn't that what the system "sounds like"? One that reproduces music without obvious problems as opposed to sounding like a system that doesn't reproduce music without obvious problems? 

[gmgraves]

15 minutes ago, sandyk said:

 Yet a device such as a DAT player or even a Nakamichi Tape Deck sounds better when numerous soldered steel links are replaced by copper wire links !

Well, steel isn't the greatest conductor of electricity, after all.

[gmgraves]

2 minutes ago, sandyk said:

 

No, but the combined resistance of all the straps is likely to be way less than the less than the resistance of your copper interconnects, especially when you add in plug and socket resistances.

 

I have no experience with such modifications, so I can't really make an intelligent or useful comment. I'll just have to take your word for it that the improvement is audible in a DBT between two identical samples, one modified in the manner you outlined and the other left stock. I assume that this is how you ascertained that the unit with the copper straps sounded better than the unit with the stock steel ones. 

[gmgraves]

11 minutes ago, sandyk said:

 

 A friend and myself had similar models.

No, we didn't feel the need to do pointless DBTs.

 

I see. OK.

[gmgraves]

3 hours ago, Ralf11 said:

comparisons are nearly pointless without DBTs

 

- there is a huge cognitive psychology literature about this, including cross-modal sensory issues, not to mention "label whore" effects in wine tastings, food tastings, and on and on

 

- the effects are not limited to humans but are known in other mammals and birds

 

The reason they work is because they not only eliminate sighted and conformational biases, but, at least in audio terms, they do not rely on a long term sonic memory, which humans do not have. The instantaneous switching between one DUT and another will show an equally instantaneous difference in SQ (if one exists). The caveat here is that the DBT must be scrupulously perfect to be useful. That's easy with passive components or ancillary components not actually in the signal path, but very difficult with active components due to the need to match the level between DUTs precisely. I've read where even a difference of a single dB will cause an invalid result. Add to that the necessity for the un-involved switching operator to also not know what he's switching, or indeed if his action switched anything at all, and that the involved listeners should not be able to see the operator initiate any action, and setting up a proper DBT becomes very difficult. If one participates in a DBT and tells others about it, or publishes the result of a DBT, It still doesn't actually prove anything because one rarely can have the assurance that the test was scrupulously set-up and carried out. Since Interconnects have no insertion loss, and switching between high-level inputs on an amp is straight-forward, those can be successfully carried out by a dedicated group of curious audiophiles, but all others, should be viewed with a very critical eye.