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Subject:Digitize cassettes at 4x speed
Posted by: bunyabunya
Date:6/16/2004 4:46:15 PM
Several people on this forum and on the Tascam forum gave me good advice on how to speed up digitizing voice cassettes. The sum total of their advice was that I could use a Portastudio, but II was not sure. A Tascam 424 Mark III arrvived today, and somewhat nervously I tested it out. It worked! I played a cassette at 2x speed, and used two of the direct port outs to copy a mono cassette to a file, and then used Sound Forge to reverse one track and pitch shift both of them to normal. A/D on a C120 would be a half hour. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Chienworks
Date:6/16/2004 5:45:53 PM
Faster yet than pitch shift is to simply change the playback sample rate. Near the bottom center of the waveform window is a small text box showing the sample rate. Double-click this box and type in exactly 1/2 the original number. If you recorded at 44100 then change this to 22050. That's all that needs to be done. No processing or resampling necessary. And since there is no processing there won't be any additional artifacts introduced. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/16/2004 5:51:06 PM
That's a really useful piece of information, thanks so much. I have about 1000 tapes in this project, both open reel and cassette, and this will save sooo much time in processing. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Rednroll
Date:6/17/2004 9:28:26 AM
To add to what Chienworks said. If your soundcard allows it, I would recommend originally recording at 88.2Khz. This way when you divide the sample rate playback you will still have a 20-20Khz full audio spectrum bandwidth. Using the 22Khz playback will reduce your file to playback at a maximum frequency of 11Khz. You can try this out to see this for yourself. Create a pink noise wavefile at 44.1Khz using the synthesis tool. Pitch shift this waveform by +12 semitones. This will now represent your originally recorded wave file at twice the speed. Open the Sound Forge spectrum analyzer and notice you get a full bandwith of 20-20Khz for the playback of the pink noise. Now change the properties to 22khz as suggested. Now look at the Spectral Analysis. You will see a brickwall cut-off at 11Khz. That's the Nyquest frequency due to the 22Khz sample rate playback. Frequency Max=1/2 Sample rate. So if you originally record at 88.2Khz and change the properties to 44.1, you will still get a full audio spectrum playback up to 22Khz. You could also playback the tapes at 4x and record at 88.2Khz and divide by 4, which would again put your properties setting at 22Khz. Again this would limit the bandwidth to 11Khz playback in Sound Forge, but would allow you to save some additional time. If your sound card can record at 192Khz, you can then set the properties to 48Khz allowing you to record at 4X and still get a full bandwidth of the audio with a max playback frequency of 24Khz. The higher sample rate records will increase your file size though. If hard drive space is not a concern then this would be your best case scenario. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Sonic
Date:6/17/2004 10:58:35 AM
This is all assuming, of course, that 4x tape playback is very mechanically precise. Chances are, there will be subtle differences between 4x @ 4x desired sample rate and 1x @ desired rate just due to the physicalities of shooting the tape across the heads at 60 ips or whatever. Small alignment issues, tape tension, gravity, Heisenberg, or whatever will make this a not-perfect process. Probably not enough to matter, particularly if this is just backing up PA recordings or whatever. But if the material is delicate enough (soft female vocal parts, for instance), that sort of difference might become audible. FWIW, J. Addendum, I wasn't paying attention to the title. Cassettes run much much slower than analog tape (roughly 2 to 4 ips) and have more obvious mechanical issues. So unless the quality is truly stellar, I guess this is all academic. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Rednroll
Date:6/17/2004 12:00:07 PM
It might have to be dependant upon the tape deck itself and it's playback ability. I worked in a duplication house, where we had a cassette tape duplicator which would run at 4X. In the master deck it would play the original 4 tracks at a time playing at 4X (2 forward, 2 in reverse), and duplicate to 8 additional cassettes recording all 4 tracks. We also had one that would dupe cassettes at 10x from a 1/4" master to 2 cassettes or cassette to cassette. That one wasn't always reliable and you always ran the risk of snapping an old tape at the 10x playback speed. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/17/2004 12:24:08 PM
Had problems with ground loops, so use an Xitel INport, http://www.xitel.com/product_inport.htm which works very well. It has good, but not the highest sound quality; for these voice tapes it seems fine. I am not sure it will allow me to record at 88.2 Khz. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Rednroll
Date:6/17/2004 3:38:02 PM
If it's just voice, then you should be fine with the 22Khz final sample rate. Not too much sound of a voice enters above that 11Khz area. You'll probably lose some high frequency noise due to tape his, getting rid of everything above 11Khz, so it may actually be a benefit to do it this way. Your card probably will at least record at 48Khz, so you could then change the properties to 24Khz, and get a higher cut-off frequency of 12Khz, when you change the properties. Sometimes Windows will allow you to record at 88.2Khz, eventhough your sound card does not support it. It's actually recording at 44.1Khz, with some oversampling conversions that Windows handles. You can give it try and see if it works. Try recording at 88.2Khz with a playback of 4x, don't playback the file in soundforge. Reverse the backwards track, then change the properties to 22Khz. Then play it back to see how it turned out, after you change it to 22Khz. Check to see if you get any pops and clicks in the recording. I say not to play it back after you first record it, because you're soundcard may not allow the 88.2Khz playback, although Windows is handling some sample rate conversions, but sometimes doesn't do it well and you will hear some pops and clicks, that may or may not be in the actual recording. Just open the record Window, select NEW and change the sample rate in the drop down box. You should see 192Khz, 96Khz, and 88.2Khz. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/24/2004 8:09:03 PM
Have done about 200 tapes, and it's going smoothly. Sound Forge is working out very well. It suddenly occurred to me, "Why not do two tapes at once?", using a tape player plugged into the sound card in addition to the one going thru the usb port. It worked! Going to save about three hours a day. But it's only at 1X, since it's a conventional tape player. Even so, it turns out to have a more muscular drive than the Tascam, and can play several sticky tapes the other couldn't. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Sonic
Date:6/25/2004 7:21:13 AM
Since Sound Forge doesn't support multiple instances and will only record from one device at a time, I'm curious as to how you are doing this. How is this routed? J. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/25/2004 7:43:09 AM
It only worked for three and a half C120 tapes and then the software I was using to go thru the sound card, WaveRepair, locked up. The other recorder, LP Player--came with the INput unit--is still working fine. The INput unit has its own sound card and goes thru a usb port. I have only had Sound Forge about ten days, and had these other sound recorders going previously, so was familiar with them. After the WaveRepair failed, about an hour ago, I riefly tried to figure out how to replace the WaveRepair with Sound Forge but was not able to do it. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/28/2004 2:24:22 PM
Finally got the SF going, and recording from two cassettes at once again, seems stable. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Rednroll
Date:6/28/2004 2:45:14 PM
Same question as Sonic. You mentioned recording from 2 sound card devices at once, Sound Forge will not allow this. Previously, you outlined that the recordings where mono, and you where recording 2 tracks at a time, one playing forward and the other in reverse. Sound Forge is capable of doing this, because it can record a 2 track stereo input, but only from one device. So I guess at this point we're all a little confused on what your setup is now. It sounds like you're recording from 2 seperate soundcards, 2 tracks at once on each (ie forward/reverse). This is just not possible with Sound Forge as Sonic mentioned, it only allows one instance of Sound Forge open at once, and Sound Forge can only record from one device at a time. If you're recording from 2 cassettes at once, then this means, you're recording a Stereo file with one cassette feeding the left input and the other cassette feeding the right input, so it no longer has the ability to record the track playing backwards as you previously outlined in your setup, that you where trying to achieve. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/28/2004 3:00:06 PM
Sorry for the confusion. Hope this is clear: Recording stereo tracks from cassette with SF thru the computer sound card [SoundMax]. The other sound card is taking tracks 1 and 3 from a Portastudio, which has four direct tracks out, via the INport [not INput] device, and it has worked steadily; the software, LP Recorder is pretty quirky, but you can get it going. Have to reboot it a lot. But it has autovolume control, which is nice. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Chienworks
Date:6/28/2004 6:45:49 PM
So you were recording two of the tracks in Sound Forge and the other two tracks with LP Recorder. Ah. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/28/2004 7:24:31 PM
Maybe you can explain this: three times tonight the SF has just stopped getting a signal from the cassette player, but keeps on recording. Why? Well, it turns out to be due to the Recording Control "line in" select box being somehow automatically unselected. I am surfing around while recording, could that have something to do with it? Or perhaps as the LP Recorder unit stops and starts, or I reboot it, that affects the sound card controls. Will keep an eye on that select box more carefully as I process thru the LP Recorder. If I could pick up another Portastudio for $50-80 on Ebay, it's possible to do 80 C60s a day; have another 500 or so to do, so it would be worth it. Run it thru the Dell sound card and Sound Forge. Should be fine. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:6/29/2004 6:43:20 AM
Just figured out what automatically deselects the Line In, Recording Control: happened about five times over the past couple days. It's simple: just connecting to a streaming video cam of the harbor in Baywood Park, CA, which features lots of seagulls, fog, boats, and people walking by. http://www.baywoodinn.com/weatherfast.html Very incompatible with Sound Forge, however! |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Sonic
Date:7/6/2004 8:41:16 AM
If you have the decks and a multiple sound cards (or a multi-input one), you could just use a multi-track like Vegas to do the recording in a single app, then adjust the files in Forge when you're done. FWIW, J. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:7/6/2004 1:46:58 PM
Thanks! I am going to give that a try. Never would have thought of it, and am getting tired of the wacky behavior of the LP Recorder. Got some more open reel to do, and another 300+ cassettes are on their way, so can try to do both onto Vegas at the same time. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: Chienworks
Date:7/6/2004 2:04:55 PM
Vegas is also a multi-instance application, which means you can have more than one Vegas window running simultaneously and they will all operate independantly. If you have two sound cards you could have "Vegas 1" recording from the first sound card and "Vegas 2" recording from the other. This means that you won't have to try synchronizing the playback of all the tapes to start at the same time. And, if some of the tapes are shorter, you can swap to the next tape while the longer recording is still going on uninterrupted. |
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Subject:RE: Digitize cassettes at 4x speed
Reply by: bunyabunya
Date:7/6/2004 2:13:08 PM
Thanks again. I have made up a couple presets for handling the noise and hum in the 1950s open reel voice tapes. There are two presets that are working pretty well. I do one, then the other, then do normalize. I get too much echo and distortion if I apply each one more than once or twice. |