How can I convert DAT audio tapes to Mp3/CD/WAV easily?

October 13, 2008 7:18 PM

I have hundreds of Digital Audio Tapes (DATs) recorded at 44.1 and 32khz LP mode I'd like to encode to Mp3 format. I have a laptop w/o a digital input or SCSI port. I would ideally like to be able to just press PLAY and have the computer convert the entire tape to a WAV file, or broken up with start IDs from the DAT tapes

I've tried to do this the digital way, at a friends house with his soundcard with digital in's but I found that the constantly switching sample rates (some songs are at 44.1khz, others at 48khz, others at 32khz Sony LP mode) caused recording software to basically get confused, and stop constantly. Plus, it's his rig, and I have 100+ tapes!

I could go analog (just play the tape on my Sony DAT deck) and record via analog line-in but that's a generation loss I'd like to avoid. Plus, I have all my start IDs written already.

Lastly my tapes are OLD. So I'd like to do this once, on the most robust machine possible. I would seriously pay up to $1000 to get these tapes (lots of rare live material etc.) converted. If it involves buying new hardware, so be it. What's the best way? A USB data drive? Software to convert the Raw data to WAV files?

posted by bmilner to computers & internet (8 comments total)

You are in for a shock.

You can't buy a new DAT deck, I don't think. Last I checked the only one on the market was a $12K broadcast unit. You can get used ones on eBay, usually. But you want a reasonably unused one that's been well cared for.

Why? DAT decks have limited head life and notoriously finicky mechanisms (there are still shops that work on them, however (ProDigital, for example). If you literally have hundreds of hours of tape, you might want to start by scouring the market for a couple of component decks with either optical or coaxial digital IO. The sampling rate problem is one you will have to deal with track by track if you want to make a digital copy. For what it's worth, I do this on a Mac Pro G5 running Leopard and recording (via built in optical) through Audacity all the time, and don't seem to have stop/start or "confusion" problems. But rather predictably, some DAT tapes will play on some decks and not others. It's a mess.

Get cracking on this if you're serious because it's getting harder to do by the month. I'm sure there are labs that will do it for you, but it will be expensive.

Truthfully, an analog dub is probably the easiest way to do this, and the generational loss, considering especially that you're converting to compressed format, will be trivial if you use a good audio I/O unit for the analog conversion. Either way, you will need to sit in front of the machine chopping up tracks. But first batch convert the tapes while you can and forget tracking until you have time later.

Here's an already dated history of the demise of DAT. I did a lot of recording on DAT in the 90s, so I feel your pain.
posted by fourcheesemac at 7:39 PM on October 13, 2008

I was always sorry DAT went away, they had limited head life but were reliable mostly. Most recording studios have DAT recorders and players and if you call around you might find someone with a deck they'd give away. I got one on freecycle about two years ago, but I used it for parts.
posted by parmanparman at 8:27 PM on October 13, 2008

some DDS (DAT for data backup) drives were audio-DAT compatible. Especially DDS2 and DDS3 drives that were made by Archive for SGI workstations. You might be able to find old units for sale online, for much less than a that of a audio-DAT deck.
posted by randomstriker at 9:51 PM on October 13, 2008

I would do the following. Get a USB sound card thing that has a digital input that matches the output of your DAT player.

After that, I think the recording software is the problem. I've never done this kind of thing, but there has to be software that will react properly to changing sample rates. Try Adobe Audition (expensive), ProTools (expensive) or Audacity (free).

I know that Audition will allow you to change the sample rates losslessly. So you could just record the stream, and then go in and slice and dice the tracks, and then change the sample rate. Because as far as I know, the sample rate is just a header in the sound file that tells the player how to output the data correctly.

I would also get into the dat player and clean the heads.

Failing that, you might have to get a piece of equipment to go in between the DAT and the computer. I have a stereo receiver that, I believe, does this automatically. It will accept various input rates and, again, as far as I know, only output at whatever rate you set.

I do like the idea of getting a DDS tape drive that will read audio. This might be an optimal solution, since it could theoretically be faster than real-time. The drive could just read the raw data off the tape, put it into a file, and you could edit it down later. Just like ripping a CD.

Failing that, if you had to go analog to do the recording, I would record the sound at a very high sample rate (48kbps, 32 bit). This would allow you to then correct for any noise induced by the analog transfer while hopefully not ruining any of the audio data. You would then make the mp3s off of that file, and either save the file natively for archival purposes, or convert it down to 44.1 16 bit CD compatible and then archive. I don't have the best ear for the nuances of fidelity, but I've done things like this and had excellent results. In all probablilty, this kind of transfer will cause so little loss that you'd be below the noise you had on the original recording.

(This may not be helpful in your scenario, but might help others in similar positions. Get a "hi fi stereo" VCR. Regular sound on a video tape is pretty bad. But the "hi fi" audio encoding on VHS tapes is top notch. It is absolutely the best consumer level analog audio recording available. You put your left and right RCA jacks into the audio in of the VCR and it will record 6 hours of audio almost losslessly. I used it quite often to record concerts broadcast over the radio. Second only to CD. Possibly has better fidelity than the original DAT.)
posted by gjc at 7:34 AM on October 14, 2008

I should also mention I'm pretty familiar with audio equipment and computers in general. So I understand matters like Digital ins and outs, and the relative merits of Hi-Fi VCRs as audio recorders (hey, I even have some shows recorded there too... another pain to convert those!) Feel free to get technical on me, I can take it!

I'm really attracted to this Audio-compatible DDS drive idea someone mentioned. Anyone have more info on that?

With all the sample rate issues I've had (I have Soundforge to convert files once saved) I'm tempted to just do Analog dumps. Just hit play... walk away, come back 4 hours later.
posted by bmilner at 11:24 AM on October 14, 2008

I have in my hands a (barely used) Sony SDT-9000, which according to this site supports DAT audio.

Here is a place that purports to have the audio-enabling firmware.

After that, there are a few different audio utilities for Windows and Linux that pull the data directly off the tapes.

I've never done this myself, but all of this info I found by plugging the keywords dds2 dds3 dat audio and sony sdt-9000 dat audio into the Goog.
posted by tomierna at 10:25 PM on October 14, 2008

I just eBayed for component DAT decks and found tons of them running from $100-500.

Personally, I think it's probably a nightmare to try to do this with DDS drives, to try to update the firmware on them, etc. Guaranteed headaches. And I wonder about the head alignment issues. DAT cartridges for data archiving use much thinner base tape than DAT audio tapes do. It might work, but you'd be better off getting a few used decks until you found one that worked well, if it took that long.

But then, some people like pulling their hair out at 3AM while wondering if they've just lost all their data.
posted by fourcheesemac at 10:58 AM on October 18, 2008

I'm going to have to leave this as unresolved.
I have a DAT deck already actually that plays audio. The problem is getting the data off the tapes reliably. Doing so digitally has the problems outlined in my original question and doing so via analog in's will result in a generation loss. I already have all the software to change bitrates, edit etc. I was hoping to just hit play and come back 2 hours later and poof... it would all be either one huge WAV file with markers inserted for the Start IDs or similar.

No luck. I'll have to do it manually... Thanks everyone.
posted by bmilner at 5:20 PM on September 14