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Testing audiophile claims and myths - Page 164

post #2446 of 3125
Quote:
Originally Posted by EthanWiner View Post

Even that is dubious. Phase shift per se is inaudible in typical amounts. It's a total non-issue, a bogeyman invented by audiophile magazine writers to explain stuff they don't understand.

--Ethan

His point being, at least it's a testable claim.

It could also be testable for frequency response/cutoff of redbook PCM vs. DSD but after 24/96 PCM even that becomes an untestable claim (unless I am unaware of the common use of ultrasonic microphones)

Sounds like there may be some straws being grasped at, but the apparent willingness to provide "evidence" is interesting at least.
post #2447 of 3125
Quote:
Originally Posted by EthanWiner View Post


Even that is dubious. Phase shift per se is inaudible in typical amounts. It's a total non-issue, a bogeyman invented by audiophile magazine writers to explain stuff they don't understand.

--Ethan

I didn't say that they were correct, or that it was a real issue (and in fact, I explained in the next bit of text that you cut off why it isn't an issue), but at least it is a testable claim, instead of the handwaving around about sound stage, stereo picture, attack, and depth of image.

post #2448 of 3125

very wrong on theory, the official analog low pass reconstruction filter for SACD "true DSD" single bit output is 50 kHz and has to be >5th order to get ahead of the noise shaping, DSD out of band noise rises above the analog full scale by ~ 1 MHz

 

such analog filters have considerable phase shift and variable group delay

 

and in actual practice most SACD compatible audio PCM DAC chips today are multibit Sigma-Delta and digitally filter the DSD input to increase bit depth, merge with their internal multibit modulator and digital filters at high internal OS ratio

post #2449 of 3125
Quote:
Originally Posted by analogsurviver View Post
 

Of course you are WELCOME to ask.

 

NO. Not in a short reply. 

 

But I will do it - thoroughly. I will post the output of the following :

 

- analog cassette recorder

- analog HIFI video cassette recorder

- CD-R recorder ( redbook, 44.1 kHz/16 bit )

- PCM from 44.1/16bit to 192/24bit - various equipment

- DSD64 and DSD128 ( with various output filtering )

 

- and COMPARISONS among the above - when presented with a 1 kHz square wave at the input and output as seen on an analog oscilloscope display. Real world machines, not sugarcoated manufacturer's version.

 

Please allow a couple of days to prepare and take pics of everything mentioned - it should give everyone a pretty clear idea why I find redbook inadequate. 

 

I have to ask to get a permission to post (a portion of )  recent DSD128 recording to illustrate the whole point - but will make it available to those in posession of native DSD playback only - via PMs.

 

Enough/too much is lost if converted to PCM - even if it is 192/24. 


So why are you not including the LP in this comparison?  1 khz square wave should be most interesting.  Then you can show us how it does compared to digital.  Real world machines and all that.

post #2450 of 3125
Quote:
Originally Posted by esldude View Post
 


So why are you not including the LP in this comparison?  1 khz square wave should be most interesting.  Then you can show us how it does compared to digital.  Real world machines and all that.

I certainly can do that. But I chose to omit LP in this case - while it will be presented inn the Turntable setup thread.

It has to be properly shown where are the limitations and where do they come from.  There will be more samples of "LP" square waves than anyone can bargain for - but I want to do it right. With explanations where are the limits of even the best test records ever available - best cartridges certainly can exceed the performance of even the best cutter head in this regard. The output will reflect the true nature of test record - not the inherent

limitations of the cartridge.

 

Out of all the other media, LP still enjoys the best response to square waves. There is one (or two) flies in this ointment - cartridges capable of outperforming even DSD on square wave signal are either no longer available - or costly beyond reason. They never were cheap - but top carts from early/mid 80s, while undeniably expensive, still did not burn such a big hole in one's pocket. Not 5 figures, even if adjusted for inflation.

post #2451 of 3125
Quote:
Originally Posted by analogsurviver View Post
 

Out of all the other media, LP still enjoys the best response to square waves.

Surely you're joking with this statement...

post #2452 of 3125
Quote:
Originally Posted by analogsurviver View Post
 

- and COMPARISONS among the above - when presented with a 1 kHz square wave at the input and output as seen on an analog oscilloscope display. Real world machines, not sugarcoated manufacturer's version.

 

Please allow a couple of days to prepare and take pics of everything mentioned - it should give everyone a pretty clear idea why I find redbook inadequate. 

I use my ears to listen to music. You will have to demonstrate why the appearance of square waves should be relevant to what I hear.

post #2453 of 3125
Quote:
Originally Posted by cjl View Post
 

Surely you're joking with this statement...

Absolutely not. 

 

That is why I would like to present the issues with turntable square waves - once undersatood what is/was engraved in the groove and how that should look like on an oscilloscope, there is no other conclusion possible.

 

Sure wish JVC made their in-house test records ( NEVER made available to any third party ) used for the development of CD-4 cartridges ( best of which was EXTREMELY well behaved beyond 60 kHz - in 1976 or so (!)  ) available at least to the professional market. They were cut at 1/10th of real time RPMs ... - making possible to test carts for pulse, which is better yet to establish transient behavuiour of cartridges than using square wave.

 

CBS STR 112 is the most prolific and de facto standard in square wave test records.  Very few are aware of its sucessor, the CBS CTC 310. They give markedly different response with any cartridge with sufficient bandwidth to allow these differences to come trough. Neither of these two records is "perfect" - but taken together it is possible to speculate what the cartridges are actually doing. If the clear, consistently repeatable pattern emerges using a large group of cartridges, the culprit must be the test record(s).

 

Like I said before, better/best cartridges exceed the test records in this regard without a single drop of sweat. Specs for cutter heads and cartridges are certain to back up this conclusion.

 

It is only because of these reasons I chose to omit square wave response from the LP in survey proposed above. Reader without sufficient knowledge/understanding might hastily jump to improper conclusion.  

post #2454 of 3125
Quote:
Originally Posted by higbvuyb View Post
 

I use my ears to listen to music. You will have to demonstrate why the appearance of square waves should be relevant to what I hear.

No problem. I learned to observe the music as seen on the oscilloscope while listening to it at the same time - using fast phono cartridges and FAST electrostatioc headphones, both of which exceed the redbook  - at least twice -  in speed. 

 

Knowing what square waves look like when fed trough the usual RIAA filter, and how hard it is to record and play them back in the first place is, I was shocked to discover it actually is possible to record and reproduce extremely close to square wave shape of signal of actual music - with analog record. One good example is http://en.wikipedia.org/wiki/I've_Got_the_Music_in_Me_(album)

 

I used to sell CDs in retail - and dreaded mondays, when there was a fair possibility I will have to endure the same recording that started its life as analog tape transferred to analog record listened to over weekend - on the CD, as demo for the prospective customer.  There is very little point of having an actual redbook master transferred to LP - there is nothing LP could do better, with all the defects of real world analog - the worst of both worlds, if you will.

 

I will describe the audible differences in detail - but please note, equipment that does justice to these relatively small differences without impacting its own stamp on the resulting sound does not come cheaply. What is enough for the reproduction of redbook is hopelessly inadequate for analog record. Sad, but true. I only wish it would not be so, as it limits the enjoyment of recorded music at this level to those that can afford it. 

post #2455 of 3125

When you think about it, it makes sense in a thread about audio myths...

post #2456 of 3125
Quote:
Originally Posted by analogsurviver View Post
 ... With explanations where are the limits of even the best test records ever available - best cartridges certainly can exceed the performance of even the best cutter head in this regard. The output will reflect the true nature of test record - not the inherent limitations of the cartridge.

 

I recall one test where the cartridge appeared to be ringing slightly on square wave transients, but a microphotograph of the test record groove showed it was actually caused by resonance in the cutter head / amp. I think I still have the report, I'll check.

post #2457 of 3125
Quote:
Originally Posted by Don Hills View Post
 

 

I recall one test where the cartridge appeared to be ringing slightly on square wave transients, but a microphotograph of the test record groove showed it was actually caused by resonance in the cutter head / amp. I think I still have the report, I'll check.

Yes, it is the CBS STR 112 test record. I will explain in detail how this ultrasonic ringing at approx 35 kHz got finally nailed - MM cartridges due to their electrical properties ( at least most of them - there ARE exceptions ) roll off just above 20 kHz, the usual point to which they maintain flat response is approx 27 kHz, followed by a steep rolloff above.  Square wave with these looks fairly good - the most widely known and acknowledged representative of this kind of transducer is Stanton 681 family.

 

Enter MC cartridges: with their far lower output impedance, they are all but invulnerable to the electrical load and they present an almost exact replica of the mechanical portion of the transducing system. Here, this ultrasonic ringing was clearly visible - MODIFIED by the non linearities in frequency response of the mechanical part of ther transcduction system, stylus/cantilever/tension wire (if used)/elastomer suspension/output wiring. Any and all of them can put resonance(s)

waaay up from 20 kHz and only trough meticulous attention to every detail and interaction it is possible to realize "flat" transducer. These tend to be $$$$ as a consequence.

 

The first cartridge that historically got it right was the Technics EPC 205CMK3 ( or one of its variants, there were normal 1/2" mount, integrated headshell and P-Mount versions, all with the same spec ). To make it even more exceptional - this is a MM cartridge ! The output from this cart mimics the actual ringing engraved into the record as seen under the microscope the closest of them all - no exaggeration ( as is most common) neither the reduction of this ultrasonic ringing. It is reasonably flat to beyond 60 kHz.  Rare as hen's teeth - particularly in good working order, as the elastomer used in this model ages anything but well - I STRONGLY recommend to insist on trying before buying the stylus for it, regardless of the factory seal; if it rides low at far below its rated tracking force, it is useless. I gave up after n attempts, n being higher than normal reasonable human being is willing to go. But if and when working ... - it would make such mockery of redbook version of the same originally ANALOG recording that it is trully embarrassing.

 

Technics went on - all the way to the EPC P100CMK4 - reasonably flat beyond 80 kHz, output rated to 120 kHz. I never saw it in person, nor the photo of the square wave it reproduces; suffice to say, it was the lightest ever stylus effective tip mass, at 0.055 mg. That is roughly 4 times less than anything you can buy today... 

post #2458 of 3125
Quote:
Originally Posted by cjl View Post

I didn't say that they were correct, or that it was a real issue (and in fact, I explained in the next bit of text that you cut off why it isn't an issue), but at least it is a testable claim, instead of the handwaving around about sound stage, stereo picture, attack, and depth of image.

Sure, and I certainly didn't mean to disagree with you!

--Ethan
post #2459 of 3125

As promised, here are the absolute polarity tests for trumpet. Recording is correct in absolute polarity. Files have been down sized from DSD128 to PCM 48kHz/24bit . It is a short excerpt from Maurice Ravel's orchestration of Modest Mousorgsky's Pictures at an Exhibition.

 

First sample is recorded at normal position of two trumpets within symphonic orchestra - approx 5-6 metres from the microphone :https://mega.co.nz/#!zpZHhAZB!jBbJw5FeAaMGikl08aMzqjVslM6CPyaQUzNfSr49yZo

 

Second sample is two trumpets closest to the microphone within given possibilities - about 1 and half a metre away from the microphone : https://mega.co.nz/#!2sxSEA4R!yzw0qakinCvgyBp7HRire_iF5AZDj41HaXObPlw4ODk

 

Third sample is recording from the back balcony of the hall - some 20 metres from the microphone : https://mega.co.nz/#!DoBkiJjT!CJc6I6f4AvjwSkG4uiVEfi9f6M7BpS_8Y_qnQhKiD0w


Edited by analogsurviver - 3/19/14 at 2:15pm
post #2460 of 3125
I listened only to Sample 2, normal and then inverted. They sound the same to me. I listened on decent quality Sony headphones.

Usually a difference can be heard after inverting polarity only with low frequency content. And as I explained earlier, it's due to non-linearity in the speaker or headphone drivers, not the ear's ability to distinguish polarity.

--Ethan
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