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Re: [ARSCLIST] Playback on contemporary machines (was Send me a kiss by wire, baby my heart's on fire!



I forgot to mention one other element of this -- bias recovery. Theoretically, a superior magnetic head and high enough resolution digital transfer should recover bias frequency on the tape. In fact, perhaps a second head optimized for bias frequencies and staggered a standard distance from the audio head could be used, and bias assigned to a separate digital file with offset information provided in the metadata. This can then be used with Plangent or other process to correct any wow/flutter or speed variations in the original master recorder. This also fits in with the concept that what is being made in the A>>D transfer is essentially a direct copy of the magnetic media instead of a playback of the recorded signal.

-- Tom Fine

----- Original Message ----- From: "Tom Fine" <tflists@xxxxxxxxxxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Monday, July 28, 2008 7:40 AM
Subject: Re: [ARSCLIST] Playback on contemporary machines (was Send me a kiss by wire, baby my heart's on fire!



I was thinking further about this. There's a big money opportunity in here, if someone runs with this and finds it, buy me a steak dinner sometime ;)!

For the commercial copyright owners, it seems to me that this concept may offer an excellent and highly-accurate way to once and for all migrate their tape libraries off of the deteriorating original media. Even under archival storage, many tapes are nearing the end of their functional lives, and some masters have been played enough times as to be badly deteriorated already.

Here would be one system I could see as being viable and very sensible for a large music company:

1. a super-precise tape transport with excellent-quality magnetic heads is used to transfer the raw signal off the tape. The transfer should probably be to both DSD (read on, there's sense to this) and high-resolution PCM. Much testing should be done to make sure that the digital system is as precise and accurate as is possible for the formats (which, if the resolution is high enough, should theoretically mean that just about every bit of meaningful information should be transferred from the magnetic tape).

2. the standard operating MO from here would be to have these digital files live in a very robust archive with as fail-safe as possible replication, migration and backup. This is more in the realm of an IT expert than a music company and I would suggest there is an outsourcing model that makes some sense here.

3. for run-of-the-mill reissues (ie stuff with budget and time constraints), the remastering could be done all DSP, probably all or mostly automated. I would expect a middling but not terrible net quality level here, and over-aggressive use of DSP extras like dynamics control and hiss-reduction would probably degrade the net result, but tasteful application of the usual mastering tools (which would run up the budget since human hands and skills would be required) could improve the average quality substantially.

4. here's where the DSD transfer could come in. Perhaps the record company itself, or a specialty mastering house, would rig up an interface between a DSD stream and a rack of different tape electronics (it's a simple level and impedence matching thing -- and the intial input stage can be bypassed on some tape electronics with 10 minutes of solder time). These "deluxe" remasters would be "played back" to gain the desired euphonic results. Meanwhile, the tapes would not have to be played again and the "warm analogue sound" from the tape electronics could be gained in any combination or tweak desired. The further benefit is no need to maintain a precise mechanical transport, just more-simple electronics maintenance. But the big win here is, the master tapes don't get played and transported in their fragile condition. Assuming the transfer at the source was done properly (ie azimuth was correct and the A>>D chain was superb), this would be audibly identical to playing back the actual tape using the heads used at the source.

5. indeed, there may be an audiophile market in selling the raw digital transfer and letting the audiophile play it back thru the tape electronics of his choice. Never before could a listener be so close to the actual master tape. Again, the weak link here is that the source transfer needs to be azimuth-perfect and the A>>D chain needs to be superb.

6. a final benefit to the copyright owner is, he now has in his archive an unprocessed, uncolored and un-EQ'd version of the source, a digital "clone" of what is falling apart on the reel in the box. As technology, especially DSP, improves, he can hope to achieve better and better results even with the run-of-the-mill releases and can get out of the expensive business of analog expertise as the tapes crumble to dust.

More morning musings. I have no idea how much of this is already being done and what is totally impractical about what I'm suggesting. And, as I said before, I have no dog in the fight -- except as a collector and fan desiring better reissues than are the norm.

-- Tom Fine

----- Original Message ----- From: "Tom Fine" <tflists@xxxxxxxxxxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Sunday, July 27, 2008 1:37 PM
Subject: Re: [ARSCLIST] Playback on contemporary machines (was Send me a kiss by wire, baby my heart's on fire!



Along these lines ...

As DSP improves and higher-resolution and even DSD transfers become the norm, I'm wondering if it's time to start thinking about eliminating the analog electronics altogether for non-NR tapes. To wit -- a tape head connected directly, with proper impedence-matching, to a high-resolution A-D converter, perhaps with one stage of gain between the head and the converter. The EQ curve and level-normalling is then performed in the digital realm via DSP. The main advantages I could see to this would be: 1) perhaps more accurate EQ curve than can be achieved with analog components, but this may or may not be the case at the present state of the arts. 2) elimination of all noises and distortions from analog components -- now it's a whole can o' worms whether the DSP would just add less-euphonic distortions of its own. 3) perhaps less cost due to no need to maintain and/or repair old analog electronics (even the solid-state stuff will wear out eventually). 4) the creation of a market for digital-realm expertise in analog issues like EQ curves and magnetic head interfaces, thus leading perhaps to some new and innovative audio-cleanup/restoration tools and better analog-to-digital interfaces.

I have no dog in this fight, just doing some Sunday musings on an interesting topic.

One other point. As the world's fleet of tape machines get older, I think more and more are falling permanently out of spec. I think it's a great stretch to expect a 50-year-old Ampex 350 to sound anything close to original unless you are a restoration expert and have done an expert restoration on the machine or have paid plenty of $$$ to have it done by someone else. The same can be said of just about any machine ever made that has more than a few hundred hours on it and/or has not been stored in an ideal environment its whole life. And some machines have built-in manufacturing or design weaknesses that cripple them over time no matter what. Belts stretch and fall apart, for instance, even if the machine isn't used. Some of the connectors used on MCI machines corrode, no matter what. Etc. etc.

-- Tom Fine

----- Original Message ----- From: "Richard L. Hess" <arclists@xxxxxxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Sunday, July 27, 2008 1:06 PM
Subject: Re: [ARSCLIST] Playback on contemporary machines (was Send me a kiss by wire, baby my heart's on fire!



Hello, Mark and Jim and Shiffy,

I think it's important that we reinforce the lesson of playing magnetic media on the best available equipment. While there are times when playing a tape on the machine that recorded it will provide the sound that the producer originally heard and intended, in most instances, playing a magnetic recording on a high-end, late-model (but not necessarily last-model) machine will provide superior results. This means that Shiffy's one-off device is probably the best device to reproduce a wire, and it means a small handful of the best tape machine models should be chosen and preserved for playing tapes. I won't bother enumerating those models here, as I think that list is well-known.

The philosophical approach that works for me, and I suggest that everyone consider, is that machine perturbations are additive. Play deficiencies/perturbations rarely if ever "cancel out" record deficiencies/perturbations that are already recorded on the magnetic record. Therefore, the machine that adds the fewest deficiencies/perturbations that is compatible with the speed and track format (or can be made compatible) is generally the one to choose.

There are usually other competing factors driving the selection of the reproducer, but having a machine to play the magnetic records with performance better than the record machine is generally the best way in my opinion/experience.

Cheers,

Richard


Richard L. Hess email: richard@xxxxxxxxxxxxxxx Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX Detailed contact information: http://www.richardhess.com/tape/contact.htm Quality tape transfers -- even from hard-to-play tapes.




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