Ted, I understand the point of knowing about an error. But, does the tape-drive-to-computer method 
CORRECT the error for the purpose of USING the audio? That's the whole point of error-correction in 
the DAT machine design (and in CD players) -- to make the audio stream usable to the average 
listener. What is the point of transfer if the audio can't be used? So far no one has confirmed that 
the direct-to-computer method provides as good error correction abilities as just playing the DAT.

As to Shai's point about multiple passes -- I too have had success once in a while re-playing what 
had been a dropout. It doesn't work all the time, but often enough that I'll do it with problem 
tapes. And yes, problem tapes can have the "error" indicator light flashing constantly or on for 
long periods of time yet recovered music stream flowing out.

One other point -- you have the same mechanical issues with a computer drive as a DAT machine, no? 
It's the same method of a rotary head recovering data from a magnetic tape, isn't it?

-- Tom Fine

----- Original Message ----- 
From: "Ted Kendall" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, January 21, 2010 6:11 AM
Subject: Re: [ARSCLIST] DAT ripping


> Well, if an error is corrected, you won't know about it from looking at the file. If it isn't, and 
> there is no interpolation, it will show up as corrupt data. Agreed that multiple passes can affect 
> error rate one way or the other, especially with that ultra-thin tape they use.
>
>
>
> ----- Original Message ----- 
> From: "Shai Drori" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, January 21, 2010 9:14 AM
> Subject: Re: [ARSCLIST] DAT ripping
>
>
>> Okay, that I understand, but I am thinking about correctable errors. We are then assuming that 
>> both systems will correct the errors the same way since both use the schemes implemented. How do 
>> we know which system has fewer errors over the other? My experience with rotary head systems is 
>> that sometimes second or third reading yielded better results, I think due to "cleaning" actions 
>> of the previous playing. Maybe we should compare five readings of the same cassette?
>> Shai
>>
>> Ted Kendall wrote:
>>> In my view, yes.
>>>
>>> Consider - you have two data files. One is a text document (for the sake of argument). The other 
>>> is a digital audio file. Both have errors in the storage medium. This is inevitable, so we 
>>> devise error correction strategies (redundancy, check codes, etc). These allow us to correct 
>>> errors completely and accurately.
>>>
>>> Suppose now that there is an error in the storage medium which is too large to be corrected. 
>>> This will cause an obvious error in the text file, which is unaceptable, so the system does not 
>>> allow for it and declares the file corrupt. The audio file, however, can be rendered inoffensive 
>>> by interpolation, and this is implemented in the DAT audio format. If we retrieve DAT audio in a 
>>> system which does not admit of interpolation, we therefore know that the data are accurate, as 
>>> any uncorrectable errors are recorded as such.
>>>
>>>
>>>
>>> ----- Original Message ----- From: "Shai Drori" <[log in to unmask]>
>>> To: <[log in to unmask]>
>>> Sent: Thursday, January 21, 2010 7:37 AM
>>> Subject: Re: [ARSCLIST] DAT ripping
>>>
>>>
>>>> My own experience with dat is that almost all tapes have some form of errors on them. I think 
>>>> the idea in dds is that errors are better fixed than dat machines. There were many machines 
>>>> that came off assembly lines not at spec, thus making the tape not a standard tape. Some 
>>>> machines are better at coping with these (my experience with Sony is better than tascam for 
>>>> example, but I suspect this is highly subjective). All in all, I think the DAT format was the 
>>>> word digital format I have ever come across.
>>>> Also' checking two files one against the other will not necessarily prove one format better 
>>>> than the other. If you get some audio, how can you be sure one stream is correct and the other 
>>>> is corrupt? Either the dat or dds stream could be better, or am I missing something in the 
>>>> methodology?
>>>> Shai
>>>>
>>>> Tom Fine wrote:
>>>>> I'm happy to do a SPDIF to hard drive transfer and then exchange tapes with someone using a 
>>>>> PC-drive transfer system so we can do the comparison Richard mentions.
>>>>>
>>>>> Please ping me off-list if you have a working PC-drive transfer chain and want to exchange 
>>>>> DATs and computer files.
>>>>>
>>>>> -- Tom Fine
>>>>>
>>>>> ----- Original Message ----- From: "Richard L. Hess" <[log in to unmask]>
>>>>> To: <[log in to unmask]>
>>>>> Sent: Wednesday, January 20, 2010 5:14 PM
>>>>> Subject: Re: [ARSCLIST] DAT ripping
>>>>>
>>>>>
>>>>>> Hi, Tom,
>>>>>>
>>>>>> After I saw your post and re-read Jim's post, I think I understand where he is coming from.
>>>>>>
>>>>>> What we _should_ be able to do is take the DDS ripped file and an AES/SPDIF'd copy of the DAT 
>>>>>> from an audio DAT machine, align the starts, invert the phase of one, and get dither or 
>>>>>> silence.
>>>>>>
>>>>>> In both instances, we're pulling numbers off the tapes (although the basest representation of 
>>>>>> the numbers is analog on the tape, the processing in both instances interprets these analog 
>>>>>> signals as either ones or zeros).
>>>>>>
>>>>>> I would not, without doing the tests that Jim is talking about, be 100.0000% confident that 
>>>>>> the two files are identical.
>>>>>>
>>>>>> I think that the DDS reading could be "better" than the audio DAT reading as there is no 
>>>>>> error concealment stage in a data recorder, so if you grabbed all the bits via the DDS route, 
>>>>>> you could be sure that they were correct.
>>>>>>
>>>>>> These are all subtle differences and are probably not as large as the "Interstitial Errors" 
>>>>>> that Chris Lacinak is talking about here:
>>>>>> http://www.avpreserve.com/wp-content/uploads/2010/01/Digital_Audio_Interstitial_Errors.pdf
>>>>>>
>>>>>> I would expect some burst differences between the two methods, and those bursts would be 
>>>>>> where the audio DAT's error concealment kicked in. Other than that, they should be identical, 
>>>>>> presuming you haven't introduced an interstitial error in one copy or the other.
>>>>>>
>>>>>> I'm glad to see Chris offering to help. I am interested in this. I would also like to know 
>>>>>> who is set up with the DDS Mass Ingest of DATs as I am sometimes asked who can do large DAT 
>>>>>> collections. At the moment, I am not interested in doing any because of anticipated remaining 
>>>>>> headlife on my machines, the growing lack of parts for DAT machines, the need to transfer my 
>>>>>> own DAT collection first, and the analog work that I have piling up.
>>>>>>
>>>>>> Cheers,
>>>>>>
>>>>>> Richard
>>>>>>
>>>>>> At 04:27 PM 2010-01-20, Tom Fine wrote:
>>>>>>> Hi Jim:
>>>>>>>
>>>>>>> How could the data be "better" than a direct-digital out from a properly-working player (ie 
>>>>>>> no head problems or mechanical issues)? I thought the main advantage of the computer-drive 
>>>>>>> method was to save time. Is there more to it?
>>>>>>>
>>>>>>> -- Tom Fine
>>>>>>>
>>>>>>> ----- Original Message ----- From: "Jim Sam" <[log in to unmask]>
>>>>>>> To: <[log in to unmask]>
>>>>>>> Sent: Wednesday, January 20, 2010 12:45 PM
>>>>>>> Subject: Re: [ARSCLIST] DAT ripping
>>>>>>>
>>>>>>>
>>>>>>>> All,
>>>>>>>>
>>>>>>>> First, Dave, that information is very helpful.
>>>>>>>>
>>>>>>>> That said, I didn't ask because I'm worried about the theory.  I was asking
>>>>>>>> for a collaborator in testing.
>>>>>>>>
>>>>>>>> The theory's been discussed before on this list, and I'm aware that more
>>>>>>>> than one person/organization has experimented with this to some success.  It
>>>>>>>> was also *briefly *discussed at last year's conference in DC. However,
>>>>>>>> every time I've seen a discussion about the topic, it has never come along
>>>>>>>> with what matters to me: testing to make sure what's coming off the DDS
>>>>>>>> drive is the same (or better) data than what would go down the AES/EBU
>>>>>>>> pipeline.
>>>>>>>>
>>>>>>>> I'm still extremely interested in this situation, and after having had to
>>>>>>>> deal with other similar formats, I've got ideas for testing that I'd like to
>>>>>>>> do.  But I don't have a working DDS setup here.  I could build my own, which
>>>>>>>> I might do, but that's a can of worms, and there's other things to be gained
>>>>>>>> by having a collaborator in these tests.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Jim
>>>>>>>
>>>>>>> Richard L. Hess                   email: [log in to unmask]
>>>>>>> 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.
>>>>>>
>>>>>
>>>>
>>>
>>
>