Digitising cassette tapes

What You Need

1. A Hi-Fi separates cassette tape deck (a portable cassette player walkman will work, but with reduced audio quality)
2. 3.5mm stereo to two phono plugs cable lead: approx £5 in the UK (if you have a really good soundcard it will have two phono line-in sockets: so just get a standard interconnect cable)
3. A soundcard that accepts line-in: most motherboards these days have this on board
   1. Or maybe use a DAP like the iriver H1xx series that has Rockbox installed ¦-)
4. A cassette tape cleaner to clean tape heads or use pure isopropyl alcohol and lint-free swabs (cotton wool buds will be ok also). This will help to capture a better sound since the cassette tapes will likely be old and dirty
5. An audio capturing/editing software application. I personally use Audacity as it's very easy to use, is free and open source, and has many plug-ins available (LADSPA / Nyquist / VST Plug-Ins). There are other apps that will do the same job
6. A lossless audio encoder like FLAC or WavPack: this is so that once you've got the audio in the state you're happy with, you can encode it to a lossless format for archival purposes. You can then transcode it to MP3 etc for upping
7. A lossy audio encoder like LAME for MP3

What To Do

Capturing/Recording

1. Connect the left & right plugs of the 3.5mm stereo to two phono plugs cable lead to the cassette tape deck and the single 3.5mm stereo plug to the line-in on the soundcard
2. Ensure the sound recording capabilities on your computer are enabled: (for windows) Control Panel > Sounds and Audio Devices > Audio tab > Sound recording > Volume > tick 'Line In'

   tip: fast forward and rewind the cassette tape before playing it. This will tighten up the tape inside and help prevent it being 'chewed-up' by the tape deck

3. Sample rate should be set to 44100Hz. Sample format should be set to 16-bit. Given the relative low quality of the analogue audio in the cassette tape, you'll be very unlikely to notice any improvement in sound quality with higher settings; CD is 44100Hz!

   The only time I'd recommend higher settings, such as 48000Hz and 24-bit/36-bit, is when you have a very good soundcard and a good quality recorded tape and/or you will be doing lots of manipulating of the recording. Each transform, such as Noise Reduction, will produce quantization errors. Ideally the editing program dithers the transform (if working in 16-bit), which means more noise added. However, due to the high intrinsic noise of recordings from cassettes, this is unlikely to be distinguishable for the 'normal' amount of editing (see 7. & 8. below)

4. Play the tape and start recording: this is a test! because you'll need to fast forward to random parts of the tape to try and find the loudest section: use that as your basis to adjust the line in recording volume so that there is no clipping. Ideally, you want to capture the audio at -5db. In Audacity you can view the sound wave in db format, so that will show you what db level you are recording at. It's always better to record at a lower volume and then increase it after you've captured the audio. And don't get worried about it looking like it's at a low volume; it will be fine
5. After you've sorted out the line-in recording volume level, you can start to record the audio... press record basically
6. Once the recording process has finished, you might want to go through the audio to edit out any parts that you do not require. Namely the silence at the start and the end of the tape. If you want to, it would also be wise to fade in and fade out now whilst you have the audio in this 'raw' format
7. You might also like to remove any 'hiss' or reduce certain noises (tape hum). Audacity has a 'Noise Removal' tool that is quite good. Be warned though: it will often result in a slight loss of high-end audio that might make it sound worse than the original. I don't normally perform this action unless there is a lot of hiss. Adobe Audition has a very good Noise Removal tool, but the program is also quite expensive
8. Once you've completed manipulating the audio, I'd recommend running the file through WaveGain. This is based upon the ReplayGain standard and will effectively apply gain (volume) adjustments directly by adjusting the scaling of the samples. Unlike ReplayGain, this is not a lossless process an cannot be reversed. It basically means the files are adjusted to -89db, which normally results in a smaller file size too, as most people tend to record at too high a level. If all music was the same relative volume, we'd never need to change the volume control on our equipment if we always wanted the same absolute volume

Encoding

1. Given the effort and time taken to capture and manipulate the audio, I'd highly recommend that the final file is encoded to a lossless format such as FLAC or WavPack. This means you are left with a perfect archival backup of the audio captured, it's smaller in file size than a wav file, and you are free to convert (transcode) to any of the lossy Audio Formats you like whenever you like, such as MP3 or Ogg Vorbis or AAC etc etc
2. For upping at themixingbowl.org I'd recommend the file is encoded to MP3 using the LAME encoder.
3. And don't forget to tag the file. If you can add as much relevant info into the tags and in a logical way, then the downloaders will not need to change the tagging and thus can keep seeding for longer (ever!)

A Final Word

If you really value your cassette tapes recordings then it's recommended you purchase a high-end audio editor as it will give better results than free audio applications. You can also search the internet for perhaps a better, and certainly more detailed technical information about cassette tape audio capturing. This is just how jaybeee does it with pleasing results from fairly cheap equipment and free software.