Digitizing lecture cassettes project - guidance requested

[jelson]

Hi everyone,

Found this forum while doing research on audio interfaces. First, thanks for all the noob stickies and articles. They've been quite educational.

A small non-profit has asked me to help them get started on digitizing their collection of lectures recorded on cassette tapes. I've estimated there's somewhere around 500+ aging cassettes: Some date back to 1990.

All were mono-recordings made on a consumer-grade cassette recording with an external microphone placed in front of the person speaking. (There are also questions from the audience, but naturally they are hard to clearly hear.)

Hardware I have to work with so far:

• Toshiba laptop running Windows 7 64-bit (AMD Triplecore 1.8 GHz w 4 GB RAM)
• dual cassette deck (consumer-grade, component: Sony TC-WR700) w. 2ch RCA line-out
• Hosa dual RCA to mini-stereo cable

I've already ran a couple of experiments recording with Audacity after adjusting the input levels via Win7 audio controls:

• via inputting into mic jack
• inputting into a Vansonic USB soundcard (cheap speech recognition device sold by Nuance)

Naturally, both leave something to be desired, but input into mic jack was better. And much of what I've read says motherboard-based audio chipsets suffer from lots of noise.

Key considerations:

1. I'll be setting this project up, overseeing the digitization, and handling the post-digitization process. Since others will be doing the actual digitization, I need to keep keep it simple so it's easy for them to do it right. Also, I'm doing this as a freebie.
   
   
2. I understand that I'll need to do post-digitization processing to remove tape hiss, line-noise, etc and to make questions from the audience more audible as well as to otherwise clean it up and make it sound as good as possible.
   
   
3. I'm limited to USB solutions since this laptop lacks Firewire.
   
   
4. Most of what I've read is geared to people doing home recording of music, but I'm just looking at speech. I've been looking at hardware solutions ranging from the Behringer UCA202 up to the Tascam US-144mkII.

My questions:

1). From what I've read here and elsewhere, 16-bit 44.1 KHz appears way more than sufficient for a lecture recording. There's no need for overkill, so what would be the hardware solution for achieving the best, reasonable digitization?

2). I've already experimented with Audacity and have already downloaded Kristal AudioEngine and Reaper. Given the considerations I've listed, what your recommendation for the software solution?

3). Since it isn't a common concern, any specific guidance on making the audience questions clearly? (Been suspecting the answer might be compression.)

4). After finishing post-processing, I'll need to archive the lectures for long-term storage. I've been thinking about using FLAC since it's loss-less, becoming more and more standard, and it's half the size of wave files. Suggestions and recommendations?

Sorry for such a long post, but I wanted to try to provide the information I could anticipate you might need. Thanks in advance.

 

[witzendoz]

You know you could just use one of these. 16bit 44.1 is fine for cassette conversion. If the cassette is mono record the 16bit 44.1 as a mono recording. Software wise most will work fine, I use sound forge for this stuff.

Also I would not go too crazy with cleaning up the tape hiss as I find this effects the original sound, just a little noise reduction does work ok. I would not use compression for the raising of the audience questions as the noise will increase with compression. In fact if you set up the record levels to the loudest peaks good old tape compression from the cassette helps keep it all together as the cassette won't peak above +3 output on the player. If the record levels on the tape have a few wayward peaks (audience claps, mic being hit, chair falling over) use a little limiting so that the limiter just attacks those peaks.

Most of the lecture stuff I have recorded in recent years has been stored as 320 MP3 mono.

Cheers
Alan.

 

[jelson]

I would not use compression for the raising of the audience questions as the noise will increase with compression. In fact if you set up the record levels to the loudest peaks good old tape compression from the cassette helps keep it all together as the cassette won't peak above +3 output on the player. If the record levels on the tape have a few wayward peaks (audience claps, mic being hit, chair falling over) use a little limiting so that the limiter just attacks those peaks.

Thanks Alan. Sounds like UCA202 is the way to go.

2 questions:

1). Since compression is not the answer, any advice about increasing audibility of audience questions? I know I'll be pressed about that issue.

Interesting observation. When I play the cassette on the Sony deck without hooking up the output, the level meters on the deck fluctuate in the expected range. However, as soon as I hook the line out into microphone jack on the laptop, the levels on the deck strangely peg out at the max.

2). Is the line output expecting a certain resistance (ohm) on the device it's plugged into? (expecting to be plugged into the amplifier unit of a consumer stereo system) Trying to wrap my head around that.

 

[witzendoz]

Thanks Alan. Sounds like UCA202 is the way to go.

2 questions:

1). Since compression is not the answer, any advice about increasing audibility of audience questions? I know I'll be pressed about that issue.

I am afraid that the best way is to select the section containing the question on the waveform and increase the volume of the question, if the software you are using has automated volume control you could do it with automation, that way the tape hiss in only increased for the question.

Interesting observation. When I play the cassette on the Sony deck without hooking up the output, the level meters on the deck fluctuate in the expected range. However, as soon as I hook the line out into microphone jack on the laptop, the levels on the deck strangely peg out at the max.

2). Is the line output expecting a certain resistance (ohm) on the device it's plugged into? (expecting to be plugged into the amplifier unit of a consumer stereo system) Trying to wrap my head around that.

You may be getting an earth loop between the computer and the deck which is causing a signal of some kind to be back feed to the output of the cassette deck, this will effect the meter operation, what happens to the sound when the meter thing occurs?

Cheers
Alan.

 

[jelson]

I am afraid that the best way is to select the section containing the question on the waveform and increase the volume of the question, if the software you are using has automated volume control you could do it with automation, that way the tape hiss in only increased for the question.

Considering the large number of tapes involved, automating the process would be a HUGE timesaver. Given my needs, any suggestions on the software that would make my life simpler?

You may be getting an earth loop between the computer and the deck which is causing a signal of some kind to be back feed to the output of the cassette deck, this will effect the meter operation, what happens to the sound when the meter thing occurs?

After I turn down the input levels in Win7 sound mixer, it sounds OK. It's just coming in at a high level. Same thing happened when I input via a cheap USB soundcard as well. I'm going to take another cassette deck with me next time and see what happens with it.

Looked up earth loop: not getting a 60 Hz hum and both laptop & deck use non-grounded 2 prong power cords.

Thanks again for the response, Alan. Much appreciated

 

[witzendoz]

Considering the large number of tapes involved, automating the process would be a HUGE timesaver. Given my needs, any suggestions on the software that would make my life simpler?



After I turn down the input levels in Win7 sound mixer, it sounds OK. It's just coming in at a high level. Same thing happened when I input via a cheap USB soundcard as well. I'm going to take another cassette deck with me next time and see what happens with it.

Looked up earth loop: not getting a 60 Hz hum and both laptop & deck use non-grounded 2 prong power cords.

Thanks again for the response, Alan. Much appreciated

Remember that earth loops don't only create hum in the digital world, they also create digital noise. I have an isolation box between the sound card and the analog gear in my studio and it reduced digital noise to zero. One of these. However the problem it may have nothing to do with an earth loop so further investigation may be needed.

I think most of the software you mentioned earlier would do the volume automation? I don't use any of them myself, but usually you select view Volume Automation (or something like it) and you get a volume line that you put points on where you want the volume to change, then move the volume line up and down as required. May be someone who uses this software can expand on this?

alan.

 

[bouldersoundguy]

You could use a cassette multitracker as your deck and run it at double speed to halve the digitizing time. You'll lose a bit of high frequency but that probably won't matter for spoken word cassette.

 

[rayc]

I use waverepair for LP & casette archiving & restoration.
It's a very powerful yet fairly simple program made for dealing with casette & vinyl.
It's pretty cheap & updates/grades are free after buying.
You can clean up the background noise & select them boost/EQ/compress/amplify/normilized the audience question sections quite simply as much or as little as needed.
It works at 16 for conversion to CD.
Running your line into the mic input of the laptop is potentially a proble. It'll be louder because of the preamp but that preamp will be fairly cheap & nasty. There are a squillion RCA to USB input devices around starting with a very cheap but quite usable Behringer thing mentioned above - I do use one of the Behri Controls when away from the "always set up" computer. I run a stereo tape deck into a 70's stereo amp then take the RCA line out from that using a Y cable (RCAs to a stereo jack) into a reasonable PCI soundcard's LINE IN & record directly into waverepair.
Waverepair will assist in turning a single channel mono recording into a 2 channel mono recording suitable for CD etc.
Before I had the process sussed I just used the wav recorder that came with the computer as well as the very basic sound card that ws built into the motherboard - via the amp etc of course. The recordings were fine but the results from the current set up were good enough to send me back to rerecord the stuff I'd done previously.
Files can be saved as whatever you want. Audio book MP3s are at an appallingly low resolution to my ears & I can't understand why the manufacturers are so willing do do that given that they often make them into CDs so nothing s saved in the process.
IF you're into the best qualty for the human voice then FLAC & .wav are the best options.
I like FLAC but not enough machines/players can handle it - strange but true.
Storage as FLAC will allow you great quality and less storage space required and is the way I'd go personally.
Given all the above you'd want pretty good quality onto tape to go to the trouble unless the resource is valuable in & of itself.

 

[jelson]

Remember that earth loops don't only create hum in the digital world, they also create digital noise. I have an isolation box between the sound card and the analog gear in my studio and it reduced digital noise to zero. One of these.

Thanks Alan. Rather inexpensive, so I went ahead and ordered one. Definitely worth the price.

 

[jelson]

You could use a cassette multitracker as your deck and run it at double speed to halve the digitizing time. You'll lose a bit of high frequency but that probably won't matter for spoken word cassette.

Definitely worth considering. In fact, I have seen a couple of units that will do 4X or 8X digital conversation. But we're talking $1.5K to $2.2K too. Also, some of these tapes are a bit old.

Nonetheless, thanks. I hadn't considered a multitracker.

 

[jelson]

I use waverepair for LP & casette archiving & restoration.
It's a very powerful yet fairly simple program made for dealing with casette & vinyl.
It's pretty cheap & updates/grades are free after buying.
You can clean up the background noise & select them boost/EQ/compress/amplify/normilized the audience question sections quite simply as much or as little as needed.

Thanks for the tip about WaveRepair, rayC. They've a 30-day trial, so I'll check it out too.

I'm getting the feeling that processing of audience questions is going to be a laborious process requiring manually selecting the individual sections. Not what I'd hoped to hear, but no one ever told me this was going to be easy.

Running your line into the mic input of the laptop is potentially a proble. It'll be louder because of the preamp but that preamp will be fairly cheap & nasty. ... I run a stereo tape deck into a 70's stereo amp then take the RCA line out from that using a Y cable (RCAs to a stereo jack) into a reasonable PCI soundcard's LINE IN & record directly into waverepair.

Can definitely see now there's a with using laptop mic jack.

Is there also a problem in the tape deck preamp and that's why you run it into the stereo amp and then out it's line-outs? Or is it just that output a cleaner signal?

Thanks again for the detailed sharing of your experiences.

Yeah, it's too bad FLAC isn't better supported, but it fits the bill for archiving.

 

[rayc]

jelson,
I use the tape deck into amp path as there weren't any USB devices available when I started doing this stuff. I also foind that it makes moitoring more flexible - I can switch to a decent set of speakers attached to the amp or listen via phones from the amp or the soundcard (I use an extension cable from the soundcard's out & I just swap the headphones or amp cable into that). being that I do vinyl and tape the map provides the phono preamp and added flexibility/monitoring options without having to change much about.
No real way around the audience thing - normalizing an entire file will only lift things as far as the loudest part will allow. Compression brings a whole lot of other issues with it.
Using Audacity or Reaper etc allows for to create an envelop that will lift & drop at need.
In waverepair you highlight a section and can amplify it by what ever you thing with or woithout compression so it's labour intensive but helpful as well.
on't forget the download the manual. Contact me if you need to get over a hurdle somewhere.
There is one plug in effect in Reaper that might be useful - it's in the ReaComp & a preset about being a vocal fader rider. It seems to detect vocals and tries to level them out at a certain vol. I haven't used it but as Reaper is available on an infinite free trial you might download it & try it. I use it for music making & paid for it after one project - it's that good!

 

[ecc83]

Some observations if I may?

I have had two UCA202s in 3 years (son donated the first one to a guy at the jazz club!). They do what they do very well but watch the input levels (over which there is no control) Worth putting a pot in a tin to make sure the DAW meters never kick above about -8dBFS, the 202 does not overload gracefully! They do however have a noise performance down at -85dBFS or so and are thus way better than any tape.

Win 7 "sees" all usb audio devices as "microphones" and this means the gain is far too high. No fault of the Berry box, I fell foul of this with my Allen and Heath ZED10! You need to get into the sound device control panels and turn down the gain.

Software: You must of course use what you find appropriate but do try the totally free MAGIX Samplitude Silver. One almost unique feature of Sam is that you can set the input to double mono and thus record to both tracks(most DAW software does not have a record mono "switch"). It has a built in free MP3 encoder and a cloud facility.

Sony Soundforge yes, great noise cleaner in it.

You have bought the iso box but almost all cassette decks are two core mains leads, (class 2 insulation) and thus you cannot get a hum loop.

Dave.

 

[bouldersoundguy]

Some observations if I may?

I have had two UCA202s in 3 years (son donated the first one to a guy at the jazz club!). They do what they do very well but watch the input levels (over which there is no control) Worth putting a pot in a tin to make sure the DAW meters never kick above about -8dBFS, the 202 does not overload gracefully! They do however have a noise performance down at -85dBFS or so and are thus way better than any tape.

I'd probably run through a good quality small mixer with -10dBV outs on RCAs. Or just get a decent interface with input level controls.

Win 7 "sees" all usb audio devices as "microphones" and this means the gain is far too high. No fault of the Berry box, I fell foul of this with my Allen and Heath ZED10! You need to get into the sound device control panels and turn down the gain.

That's insanely stupid even beyond what I expect from Windows. The OS has no access to the analog gain control on most devices and can only affect the gain in the digital realm. But any USB device that actually is a mic would have its own preamp so there is not even any situation where digital gain is needed. I find this hard to take literally and suspect there is another explanation.

(most DAW software does not have a record mono "switch").

Excepting Pro Tools, Sony Sound Forge, Sony Vegas (and I bet Acid) and Reaper. In fact most DAWs can record in mono.

 

[ecc83]

I'd probably run through a good quality small mixer with -10dBV outs on RCAs. Or just get a decent interface with input level controls.



That's insanely stupid even beyond what I expect from Windows. The OS has no access to the analog gain control on most devices and can only affect the gain in the digital realm. But any USB device that actually is a mic would have its own preamp so there is not even any situation where digital gain is needed. I find this hard to take literally and suspect there is another explanation.



Excepting Pro Tools, Sony Sound Forge, Sony Vegas (and I bet Acid) and Reaper. In fact most DAWs can record in mono.

Re the 202 and input controls. I think the OP is on a budget and you can get quite a few 202s and pots for 120quid!

I could well be wrong about the details of W7 and usb but that is essentially what I was told by Allen and Heath and I am sufficiently PC numptyish to do as told and if it works not ask!

I dare say that the other software CAN be made to record a single input to two tracks but Sam just makes it easy. I refer my honourable friend to the the answer I gave earlier. (about me being a PC numpty.)

Dave.

 

[bouldersoundguy]

Re the 202 and input controls. I think the OP is on a budget and you can get quite a few 202s and pots for 120quid!

Or one decent interface with the level controls already built in.

I could well be wrong about the details of W7 and usb but that is essentially what I was told by Allen and Heath and I am sufficiently PC numptyish to do as told and if it works not ask!

It wouldn't surprise me if they told you that, but it's still a weird and suspect reason. A digital gain control can't have any effect at all on the analog input stages. If something clips the converter or overloads an analog stage before the converter then reducing the digital gain will only result in a lower level clipped/overloaded signal.

I dare say that the other software CAN be made to record a single input to two tracks but Sam just makes it easy. I refer my honourable friend to the the answer I gave earlier. (about me being a PC numpty.)

Recording to mono files is the default for most DAWs that I've used.

 

[witzendoz]

Some observations if I may?

I have had two UCA202s in 3 years (son donated the first one to a guy at the jazz club!). They do what they do very well but watch the input levels (over which there is no control) Worth putting a pot in a tin to make sure the DAW meters never kick above about -8dBFS, the 202 does not overload gracefully! They do however have a noise performance down at -85dBFS or so and are thus way better than any tape.

The 202 is set for line level standard -10db, and I am pretty sure it will handle up to +4db, (so the overload would be on the software side) and will be a perfect match from the cassette deck, don't worry about pots and stuff.

most DAW software does not have a record mono "switch".

I would think all software is capable of recording a single mono track, why record double mono (which is stereo) and double the file size? Audasity does, Kristal does, Sound forge does, Vegas does (via combine), so I think the others would have a way to do it.[/QUOTE]

You have bought the iso box but almost all cassette decks are two core mains leads, (class 2 insulation) and thus you cannot get a hum loop.

In theory yes, in practice using laptop power supplies I would use and isolation box (hum eliminator) because as soon as another item is plugged in, say an amp and speakers to monitor the recording, a loop can occur.

Cheers
Alan.

 

[ecc83]

Ok, sorry. I have mixed up two different "problems" here.

First the analogue input capability. Might well be a +4dBu overload point! I will dig out my trusty Levell oscillator and check! I do know that my Sony Minidisc deck will overload it (it is even a bit too hot for my 2496 soundcards. Pot in tin time)

W7 and usb. If I setup my ZED 10 to peak to just 0vu on its excellent meters (indicated clip point +16vu but even that is not actual clipping) and run the usb lead into my HP desktop, any DAW meter shows gross overload. So back off the ZED's level? Can do but then "W7" amplifies a lot of converter artifacts and you get a 6kHz whine pop up at about neg 40. The solution is, as I said, to reduce the internal gain of the W7 usb system (by about 90%)

Mono recording? Again, bit of a mixup. I am assuming OP has a single sided input but wants a mono but two channel output? I.e. phantom mono. Again numpty! I do not know how to do this in Cubase, Sonar (X1 hate it!) or Audition.

Earth loops and laptops and amps? Point taken but a lot of "mid-fi" amps are also Class2 wired. Better long term solution is to get a lap charger that does not feed mains earth through.
Dave.
http://www.amazon.co.uk/Ground-isolator-audio-noise-removal/dp/B000KHBU1G These actually measure out pretty well. Certainly good enough for this application and well worth getting a couple as a field A saver!

 

[bouldersoundguy]

Ok, sorry. I have mixed up two different "problems" here.

First the analogue input capability. Might well be a +4dBu overload point! I will dig out my trusty Levell oscillator and check! I do know that my Sony Minidisc deck will overload it (it is even a bit too hot for my 2496 soundcards. Pot in tin time)

That sounds like the problem is in the deck. Have you tried any other sources into the 202 or or "2496" sound cards?

W7 and usb. If I setup my ZED 10 to peak to just 0vu on its excellent meters (indicated clip point +16vu but even that is not actual clipping) and run the usb lead into my HP desktop, any DAW meter shows gross overload. So back off the ZED's level? Can do but then "W7" amplifies a lot of converter artifacts and you get a 6kHz whine pop up at about neg 40. The solution is, as I said, to reduce the internal gain of the W7 usb system (by about 90%)

Inconceivable. Something went terribly wrong somewhere.

Mono recording? Again, bit of a mixup. I am assuming OP has a single sided input but wants a mono but two channel output? I.e. phantom mono. Again numpty! I do not know how to do this in Cubase, Sonar (X1 hate it!) or Audition.

If the source is mono the OP can capture, process, archive and release mono files. Putting one channel of audio into a stereo file is unnecessary.

 

[ecc83]

There is no problem with the Sony MD deck. It is just that S/PDIF recordings (from an HD Freeview tuner) slam to 0 on its meters and that results in a "hot as possible" analogue signal in PC software.
This would result in those recording being a lot louder than everything else (BBC iPlayer* grabs on the PC for instance) I am a bit of a "unity gain" nut!

The mono thing. Ha! I know it is all "mono" I just mean you need two of them to get it in both ears! Mono buttons on "hi fi" went West ages ago I think...."Stereo" does not and never did enter this picture.

*Some BBC archive stuff is similarly "slammed". B nuisance!

Dave.