[wavoman]

Quote:

Originally Posted by royalcrown /img/forum/go_quote.gif It would be much more preferable if they did a proper ABX test and asked the panel to identify which component is which, rather than just asking them what sounds better, although you'd still need to test properly for statistically significant results.

I do not think this is so. ABX is only one of many protocols, and there are good and bad things about it. Check the literature on sensory testing GIYF.

To determine in a blind test if A and B can actually be differentiated, there are other protocols -- my fave does false ("swindle") comparisons (presenting both A's or both B's, but claiming to be presenting A and B ... lots of fun!).

You can certainly ask the direct question: "Can you perceive any difference betwen this ... and this". You don't need to ask the somewhat artificial question posed by ABX. In fact I have argued elsewhere that asking the more complex question "do you like this better than ... this" can actually lead to more accurate results than the difference question, or the (strange and off-putting IMHO ABX question). It has to do with eliminating certain kinds of response bias.

We agree on this -- you must make proper statistical tests. Adding swindles (both A or both B) actually ups the statistical power of these tests in the "can you tell A from B" protocol. And you have to randomize the order presented, etc. etc.

The food industry (taste tests) almost never uses ABX, they use one of about 10 direct choice protocols. Audio for some reason -- not a good reason I'll bet, just history -- uses ABX. No real need ... many ways to do blind testing.

 

[Berlioz]

Upstateguy, I understand you may be in disagreement with some people on this thread, but there's no reason to antagonize them.

Already I can see that the some of the technical aspects involved in this discussion are beyond me (for now). Regardless, I don't think it is a flawed argument from Donald North that there are some undiscovered reasons behind why audio equipment sounds the way it does.

Are you telling me that right now, at this very moment, human science knows every single thing there is to know about electronics? Of course not. Extremely well researched and calibrated instruments still experience errors daily. They may be the result of many small, unmeasurable variances having a cumulative effect.

If there are indeed incidences of people experiencing equipment (that measures the same) sounding differently - using double blind tests, then the possibility exists that there is yet more to learn about audio.

Anyways, I have a ton of studying to do tonight, but I'll get back later; I'm curious to see how this thread progresses.

 

[upstateguy]

Quote:

Originally Posted by Berlioz /img/forum/go_quote.gif Upstateguy, I understand you may be in disagreement with some people on this thread, but there's no reason to antagonize them. Already I can see that the some of the technical aspects involved in this discussion are beyond me (for now). Regardless, I don't think it is a flawed argument from Donald North that there are some undiscovered reasons behind why audio equipment sounds the way it does. Are you telling me that right now, at this very moment, human science knows every single thing there is to know about electronics? Of course not. Extremely well researched and calibrated instruments still experience errors daily. They may be the result of many small, unmeasurable variances having a cumulative effect. If there are indeed incidences of people experiencing equipment (that measures the same) sounding differently - using double blind tests, then the possibility exists that there is yet more to learn about audio. Anyways, I have a ton of studying to do tonight, but I'll get back later; I'm curious to see how this thread progresses.

Hi Berlioz

I don't have a problem with any of the hobbyists who have posted in the thread. Everyone is entitled to their own opinion whether scientifically based or not.

I do have a problem, however, when MOTs start using the non-verifiable, non reproducible, unmeasurable rhetoric, that is the stock-in-trade of snake oil salesmen trying to promote their products, either directly or indirectly.

When someone starts talking about a higher resolution amp that lets you hear deeper into the music, or qualities an amp might possess that we have not yet learned to measure and it just so happens that they make just such an amp, your radar should light up.

Back on topic, the conundrum continues with the arrival of another DAC:

 

[Berlioz]

Well, studying is really boring - so much for that! Anyways, are you going to compare both of those DAC's? I'd be very interested in reading the results. I really wish I had the money to do this kind of thing. Some of the people on these forums have so much $$$ at their disposal. I don't really understand why they don't do blind testing, even if just to satisfy their own curiosity.

I dunno if cables make a difference or not. Scientifically, it doesn't seem like they should. However, I have no experience with them and therefore no right to comment on the matter. If I bought some ~$200 cables (which I can afford), and found them to be no better than regular ones, some people would probably say the equipment I was using was too cheap. Oh well, one day I'll find out for myself.

 

[Donald North]

Quote:

Originally Posted by upstateguy /img/forum/go_quote.gif Hi Berlioz I do have a problem, however, when MOTs start using the non-verifiable, non reproducible, unmeasurable rhetoric, that is the stock-in-trade of snake oil salesmen trying to promote their products, either directly or indirectly.

You, yourself have said "I always liked the "Tanberg sound". Similar to Blaupunkt and Grundig.... noticeably sparklier and punchier than the American stuff was back in the day."

Where's the data to support this claim?

My comments about higher resolution are equally applicable to headphones, speakers, cd players, and d/a converters.

 

[upstateguy]

Quote:

Originally Posted by Berlioz /img/forum/go_quote.gif Well, studying is really boring - so much for that! Anyways, are you going to compare both of those DAC's? I'd be very interested in reading the results. I really wish I had the money to do this kind of thing. Some of the people on these forums have so much $$$ at their disposal. I don't really understand why they don't do blind testing, even if just to satisfy their own curiosity. I dunno if cables make a difference or not. Scientifically, it doesn't seem like they should. However, I have no experience with them and therefore no right to comment on the matter. If I bought some ~$200 cables (which I can afford), and found them to be no better than regular ones, some people would probably say the equipment I was using was too cheap. Oh well, one day I'll find out for myself.

I'm not a believer in cables. Expensive cables are just foo-fa.

Unfortunately I sent the Neko back, but I still have the Stello and the Constantine and the DAC-AH. The Zhaolu died and I'm going to bring it to a DIY mini meet to see if anyone can figure out what's wrong with it.

I wouldn't mind evaluating the Neko again though. Maybe I can work something out with Wes?

It's funny that my initial impression of the North Star is that is sounds different from the Neko or the Stello....

Apparently, until you have them running head to head and volume balanced, you can imagine all sorts of things. For instance I'd say the North Star doesn't have the bass prominence of the Stello or the mid-range presence of the Neko, both of which (bass and mid-range) disappeared when I volume balanced.

But we'll see. I'm going to listen to the North Star for the next 2 weeks, just like I did with the Neko, then run the same volume balanced test head to head.

Regarding blind testing or A-B volume testing like I did, the reason it's not reported more often is that doing it is very demoralizing. IMHO, finding out that two components you thought sound very different from each other, actually sound the same does not feel good, especially if you've spent a lot of money for one of them.

USG

 

[WesMiaw]

I'd just like to chime in here regarding measurements. The problem with traditional audio measurements is they are static tones or sweeps. Even the multi-tone measurements are static. (I believe I have graphs published for the majority of the RightMark Audio Analyzer tests.)

The reality is things get more complicated once you try to play back music. I don't know of any standard measurement that handles that. I've sort of been playing around in my head of what might make sense. I used to do video compression quality research and you'd analyze each frame. The frames taken as a whole over the duration of the video could then give you a time-aware quality analysis. But no one does that with audio. I think the same basic concept could apply.

As for the DAC chip, that is really only half the equation. The other half is the analog output stage. This you can definitely measure even with static tones. One simple example: insert a resistor in series with your voltage output and you can see what happens on an oscilloscope. This resistor won't affect frequency response, noise level, dynamic range, THD, IMD, or crosstalk. But it will mess up your signal besides just attenuation.

You can use Thevenin's Theorem to try and compute this, but those computations are still based on ideal electrical properties, and the real world isn't built of ideal components (i.e. real world components are non-linear). So an oscilloscope shows you what is really happening, without having to do a whole bunch of complex computations based on assumptions.

You can also see the differences in *music* reproduction comparing two DACs (the entire unit) on an oscilloscope--if you display both channels simultaneously you can check for deviations or if you reverse one input (e.g. through a transformer) you can perform a sum and see if it stays perfectly flat. I mention the transformer because you don't want to ground the positive signal coming out of the DAC.

BTW - You can come up with a LCR circuit that will affect audio frequencies. Come up with one, then build a cable that has those characteristics, and voila.

 

[mike1127]

Quote:

Originally Posted by Berlioz /img/forum/go_quote.gif Well, studying is really boring - so much for that! Anyways, are you going to compare both of those DAC's? I'd be very interested in reading the results. I really wish I had the money to do this kind of thing. Some of the people on these forums have so much $$$ at their disposal. I don't really understand why they don't do blind testing, even if just to satisfy their own curiosity.

Hi Berlioz,

I agree with you that blind testing makes sense. I began a blind test of cables and power cords. Several more weekends to go, but here is an initial report:

http://www.head-fi.org/forums/f133/b...report-430664/

Quote:

I dunno if cables make a difference or not. Scientifically, it doesn't seem like they should. However, I have no experience with them and therefore no right to comment on the matter. If I bought some ~$200 cables (which I can afford), and found them to be no better than regular ones, some people would probably say the equipment I was using was too cheap. Oh well, one day I'll find out for myself.

That is the best attitude---you will find out for yourself, rather than looking for an authority to tell you.

Upstateguy referred to the idea that certain things should get your "radar to light up." I don't know how old you are, but I'll assume you are of college age. As I've grown from age 20 to age 40, I've had a lot of experiences that give me a sense of what things are likely to be true, what things are suspicious, and what things aren't worth my time.

For some reason Upstateguy considers Don's statements to be so far outside the bounds of reason that he would lump Don with "snake oil salesmen." I guess that saying some amps are higher resolution is one of these statements. Of course, it's up to you to decide whether it makes sense to speak of "higher-resolution amps." Maybe you have enough experience with various kinds of audio equipment that you have a sense of this. Or maybe you want to wait until you've heard more amps.

Of course, some of what Upstateguy has written could also be a good reason to get your radar to light up. For example, going to an extreme position and seeming to lump together a lot of things in the category of "snake oil" (I would call that having an undifferentiated concept). Or just plain lack of politeness, as you observed. One really interested question you will wrestle with in life---are the loudest and crankiest folks the ones with the most truth? They certainly can grab your attention. How about the quieter and more polite folks? How often do they hold deeper wisdom? It's for you to investigate and decide.

 

[upstateguy]

Quote:

Originally Posted by mike1127 /img/forum/go_quote.gif [size=medium]Full disclosure: I'm Don's friend, so this may be biased. [/size] -Mike

Spoken like a true friend.

USG

 

[upstateguy]

Quote:

Originally Posted by WesMiaw /img/forum/go_quote.gif I'd just like to chime in here....

Hi Wes

I just mentioned your name and poof, here you are.

I'm sure you read the post. I'll send you a PM.

The interesting thing is that listened to separately, the DACs each appear to have different sound signatures, that disappears when compared head to head.

I have become interested in this psycho-acoustic phenomena because my initial impressions returned when the DACs were again evaluated separately.

Curious, don't you think?

USG

 

[WesMiaw]

I actually composed and posted my response before I saw your post with my name. It takes a while to write a long post.

I specifically didn't say anything about things actually sounding different, or there being an audible difference, because that opens a whole can of worms.

But I did want to provide a method by which anyone can actually perform measurements which would illustrate differences not represented by the standard measurements or specifications. I did use the methods I described above during my research and design phase.

 

[royalcrown]

Quote:

Originally Posted by mike1127 /img/forum/go_quote.gif No.

Yes? End users don't have access to the live microphones, let alone a studio of any kind. End users only have a CD or digital music file to reproduce, not the live music itself.

Quote:

Originally Posted by mike1127 /img/forum/go_quote.gif You're adding a lot of complexity to something that is simple. One thing we can do is get rid of the recorder by hooking up a live microphone feed to the monitor room. Then go stand in the hall/studio and listen. Then go listen to the monitor. If it sounds like life, then the microphone, cabling, amplifier, and monitor speakers are accurate. If not, then they aren't, regardless of measurements.

I'm not adding any complexity, it's just that you're oversimplifying, and disregarding several aspects of, the music recording processes. Very few studios do not master the original signal (in fact I only know of one). By the time a CD reaches your or my hands, it has been altered significantly from the original playback, going through many stages of processing.

However, even pre-mastering, and even if the speakers are theoretically perfect along with the mic, cabling, and amp, there's a good chance that what you hear won't even be close to the live feed if the microphones were put in a suboptimal position - not to mention you're going to have to (in most cases) downmix several channels into stereo, which would involve - you guessed it - plenty of mastering to make sure the transition from several multiple independent recording channels into a congruent, unified, stereo track. A lot goes on from the live recording to a nice stereo track on CD, and these crucial steps cannot be discounted or trivialized.


Quote:

Originally Posted by mike1127 /img/forum/go_quote.gif It does, but it's useless to the job of reproducing music.

The music is reducible to an electrical signal, and if you recreate that electrical signal perfectly, you have reproduced the music perfectly.

 

[WesMiaw]

USG, I sent you an email to follow up.