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I forgot to mention ... what about half-speed mastering? So there you're having the tape machine 
treat the transients at half the original velocities (that might be the wrong word). How does that 
compare to original-speed fidelity? My point is, it's an interesting debate and I'm not convinced 
there's a "right" answer as long as you can have original-source azimuth alignment and make sure 
polarity is maintained. I don't consider a magnetic tape playback system capable of perfect fidelity 
from tape to tape and machine to machine, so I think you can't set hard and fast rules and, joyfully 
for some of us and dreadfully for others, we must use our ears and aesthetics as the final decider.

-- Tom Fine

----- Original Message ----- 
From: "Tom Fine" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, October 08, 2009 7:32 PM
Subject: Re: [ARSCLIST] Reverse engineering


> This backs up what I have experienced here. The reverse-copied tracks can (but don't always) sound 
> "crisper." And yes, Richard is right -- reverse polarity. You will probably hear a difference with 
> that, too.
>
> As I said in my previous post, I'm not sure what's "right" vis-a-vis fidelity since you're not 
> playing it back on the machine on which it was recorded and all head-playback 
> electronics-alignment combos have some sort of sonic signature, be it mild or not.
>
> Finally, Richard is 100% right about low-fidelity oral histories. It gets more debate-worthy when 
> you get into an instance like well-made music recordings that are 1/4-track 7.5IPS and you want to 
> ingest all 4 tracks at once.
>
> Oh, and regarding duplicated tapes ... the unfortunate truth is that there is almost never an 
> azimuth match in the two "sides." The reason, especially with quarter-track 7.5IPS reels duped 
> back in the "golden age" days of the late 50's and early 60's, is that there were two record heads 
> that were almost never in perfect alignment. I think SOME but not all later cassette dupers had 4 
> stacked tracks, but most formats from the days of Ampex 3000 series dupers had pairs of record 
> heads, one for the "side A" tracks and one for the "side B" tracks. 8-tracks would be four and 
> four, from the heads I've seen and dupers that have been described to me.
>
> The practice I ended up adopting for quarter-track tapes with music is just charge for the time 
> required and ingest one side at a time with an azimuth tweak each time. With home-made tapes, if 
> the azimuth was _really_ well aligned at the factory, you can sometimes get away with a 4-at-once 
> ingestion, but a sharp-eared client can hear the difference with transients and may not like his 
> two sides sounding different.
>
> -- Tom Fine
>
> ----- Original Message ----- 
> From: "Robert Cham" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, October 08, 2009 6:03 PM
> Subject: Re: [ARSCLIST] Reverse engineering
>
>
>>I should think that it isn't relevant to digital copying at all, but back in the analog '70s we 
>>used to high speed dub reel to reel tapes backwards because seeing a decay as a transient was much 
>>easier on the electronics than an attack, especially a percussive one.  That was the 
>>recommendation of Ampex, who built our duplicators.
>>
>> Bob Cham
>>
>>>Back in the day when duplicating tapes was a day job for me, they said that side 2 of cassettes 
>>>duped ay high speed both sides at once would sound better than the side 1 would. Never made much 
>>>difference on cassettes, especially at 64 or 128IPS dupe speed, but some people told me copying 2 
>>>tracks worked better in reverse too... They said the electronics could respond to transients 
>>>backwardsbetter than forwards. I have no empiric evidence of this though.
>>>
>>>Just old tape tales by now, but this had me thinking back... or backwards!
>>>
>>>I have transferred some quarter track tapes doing all four tracks at once top a four channel A/D, 
>>>and not noticed a significant difference, but it is easier to do them one side at a time as then 
>>>they end up tails out, as long as it is an hourly job and not a mass flat fee transfer project.
>>>
>>>Hope this isn't irrelevant!
>>>
>>>Lou
>>>Lou Judson
>>>Intuitive Audio
>>>415-883-2689
>>>
>>>On Oct 8, 2009, at 1:59 PM, Richard L. Hess wrote:
>>>
>>>>
>>>>>It's not the digital realm, its the way the reel electronics handle transients and phase
>>>>
>>>>There appears to be waveform differences between playback in the two directions after accounting 
>>>>for the polarity flip. To my ears, this is an acceptable tradeoff for copying oral history tapes 
>>>>in half the time. This is especially true of mid-to-low-fi recordings such as some 3.75 and most 
>>>>1.88 in/s reels.
>>>>
>>>>Cheers,
>>>>
>>>>Richard
>>
>