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Old 27th August 2012, 12:31 AM   #27031
RNMarsh is offline RNMarsh  United States
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Default measure the wholechain

Quote:
Originally Posted by Ken Newton View Post
Scott, I think, perhaps, the most important point of Dave's investigation may be that it recognizes there is something to be investigate. Meaning, there are time-domain distortions associated with bandlimited sampling and reconstruction. Attempting to quantify the subjective impact (if any) of such distortions on music reproduction is a seperate thing. I've found the first task is simply getting the basic recognition that frequency-domain performance doesn't necessarily alone define technically perfect reproduction of a signal. It may also depend on how sensitive the signal and the receiver are to time-domain distortion. In the case of digital audio, the receiver is the human hearing system. After that recognition, the rest becomes a debate over the audible significance.

I haven't yet examined Dave's research, but will check out the link you provide, thanks. I would add, however, that the time-domain questions aren't single dimensional. By which, I mean that a typical digital audio recording and playback chain will have multiple impulse reponse functions stemming from the multiple bandlimiting filters in the chain cascaded with each other. I've suspected that these cascaded functions may be dynamically interacting with each other to deleterious effect. Perhaps, there is an effect taking place which is akin to the multiplying of distortion order when cascading stages of a linear amplifier. But that, admittedly, is only conjecture.
I am pretty sure I said awhile back here -that one needs to measure the whole entire chain and not one or two pieces of equipment in isolation to see what the distortion is in total... that which we have to endure in listening to hifi music. The recording chain and the playback chain... I would bet a whole dollar that it is pretty ugly.... Doing such an exercise will point to the culprits responsible for the such miserable state of hifi after so long. We know two major points are the recording methods and the speakers and the way they are used etal. But, almost as bad is from recording mic preamp to power amp speaker terminal as a whole string/chain. -RNM
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Old 27th August 2012, 01:15 AM   #27032
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Quote:
...But, almost as bad is from recording mic preamp to power amp speaker terminal as a whole string/chain.
well yes what do you expect if you saturate tiny rust particles glued to a piece of mylar being dragged across over, around, through a maze of metal and plastic guides, idlers with mechanical speed variations from seconds down to uS in motors, bearings, stick slip

set the “0 dB” level to where the tape is saturating enough to give 3% 3rd harmonic distortion – then regularly record above 0 db

don't forget to "dither" those saturating particles with 100+ kHz AC bias if you want any low level linearity at all - at least for those particles that didn't fall off with all the rubbing or get remagnetized by the adjacent layer of tape...

repeat the record/playback a few times in mastering, editing - likely move to a different tape machine for feeding the cutting lathe - hope the tech really knows what to do with the head alignment, frequency test tone tracks you did remember to include on the master

could write several times as much about the vinyl cutting, replication, playback process off the top of my head but dinner calls....

Last edited by jcx; 27th August 2012 at 01:27 AM.
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Old 27th August 2012, 01:27 AM   #27033
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Quote:
Originally Posted by jcx View Post
well yes what do you expect if you saturate tiny rust particles glued to a piece of mylar being dragged across over, around, through a maze of metal and plastic guides, idlers with mechanical speed variations from seconds down to uS in motors, bearings, stick slip

don't forget to "dither" those saturating particles with 100+ kHz AC bias if you want any low level linearity at all - at least for those particles that didn't fall off with all the rubbing or get remagnetized by the adjacent layer of tape...

repeat the record/playback a few times in mastering, editing - likely move to a different tape machine for feeding the cutting lathe - hope the tech really knows what to do with the head alignment, frequency test tone tracks you did remember to include on the master

could write several times as much about the vinyl cutting, replication, playback process off the top of my head but dinner calls....
Which is why digital will win in the end, and by a big, big margin. At the moment we have a car, CD, with engine capable of 200mph but everyone thinks equipping it with suspension and brakes from a car designed for a maximum of 100mph is good enough ...

Frank
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Old 27th August 2012, 03:46 AM   #27034
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John - i have an OPPO with upgraded power supply that I primarily use as a transport for my PMD 200 equiped 1704 Burr Brown DAC (last version of the HDCD decoder ) 24/96 with jfet analog stage. I find the Oppo 95 analog stage even with upgrades not much better than older CD players - the analog stage still needs a lot of work, even though it's marketed as the cats meow of modern players with it's 32 bit 192 khz Sabre DAC . It's a great universal transport though and sounds better through older DACS which have more room to build shunt regulators and discrete output stages

Last edited by ticknpop; 27th August 2012 at 04:03 AM.
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Old 27th August 2012, 04:13 AM   #27035
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Quote:
Originally Posted by jcx View Post
well yes what do you expect if you saturate tiny rust particles glued to a piece of mylar being dragged across over, around, through a maze of metal and plastic guides, idlers with mechanical speed variations from seconds down to uS in motors, bearings, stick slip

set the “0 dB” level to where the tape is saturating enough to give 3% 3rd harmonic distortion – then regularly record above 0 db

don't forget to "dither" those saturating particles with 100+ kHz AC bias if you want any low level linearity at all - at least for those particles that didn't fall off with all the rubbing or get remagnetized by the adjacent layer of tape...

repeat the record/playback a few times in mastering, editing - likely move to a different tape machine for feeding the cutting lathe - hope the tech really knows what to do with the head alignment, frequency test tone tracks you did remember to include on the master

could write several times as much about the vinyl cutting, replication, playback process off the top of my head but dinner calls....
About once a day I have to look at the sky and be amazed anything
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Old 27th August 2012, 04:32 AM   #27036
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Old 27th August 2012, 05:18 AM   #27037
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Quote:
Originally Posted by ticknpop
John - i have an OPPO with upgraded power supply that I primarily use as a transport for my PMD 200 equiped 1704 Burr Brown DAC (last version of the HDCD decoder ) 24/96 with jfet analog stage. I find the Oppo 95 analog stage even with upgrades not much better than older CD players - the analog stage still needs a lot of work, even though it's marketed as the cats meow of modern players with it's 32 bit 192 khz Sabre DAC . It's a great universal transport though and sounds better through older DACS which have more room to build shunt regulators and discrete output stages
I've heard many very favorable reviews of the Oppo 95 via it's analog stereo output, even in comparison to some $5000 DACs. I don't have the Oppo 95 but the older Oppo special edition with NuForce mods (Nuforce Edition). Has the same Sabre 32 DAC. It can sound very very good, with good source material.

Subjective opinions vary of course, though many say the Oppo sounds laid back. I heard one person prefer his upfront sounding older DAC.

But, I've had expensive CD Playback in our system, and the Oppo has been my personal favorite, plus it plays all different formats. I prefer it our Sony SC1 and Benchmark DAC though the Benchmark is close. The Oppo seems to have a more full bodied sound.

Just my subjective opinion though. We all have our preferences. And we all have different systems, so one component may compliment one system better than another.

John
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Old 27th August 2012, 05:24 AM   #27038
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One thing I was going to mention to JC, but didn't was how good many HDCD recordings can sound on the Oppo, even when compared to good SACD or Bluray. I never know what stuff is HDCD encoded till I put it in. But it's nice to see that it's still being used on some new popular music.

John
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Old 27th August 2012, 07:10 AM   #27039
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For the record, 0Vu on the meter of an Ampex master recorder initially represented 1% distortion in about 1950. By 1968, the distortion had dropped to about 0.7%, following significantly further in the next 10 years by at least 4 times, maybe more. Some people reset their Vu meters to a higher operating level, but not everybody.

Last edited by john curl; 27th August 2012 at 07:19 AM.
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Old 27th August 2012, 01:53 PM   #27040
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Quote:
Originally Posted by Ken Newton View Post
Unfortunately, inherent in this notion is that old bias of deeming a measurement which doesn't appear offensively to the eye is therefore, not offensive to the ear.

Of course the reverse is also true.
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