The audio cassette, officially introduced in 1963 as the Compact Cassette, had a long run as an analog medium for recording and playing music although it was originally designed for use in dictation machines. People often have cassette recordings on topics such as family history, early audio of children learning to speak, concerts, and historical events. As with all analog formats, cassette tapes decay over the years. The iron oxide on the tape can flake off and the tape material can become brittle. If you want to save these recordings, having them digitized is your path to preserving them.
Should You Bother?
Although cassette music recordings on chrome and metal tape could be quite good, the audio quality was never up to CD or even vinyl quality. If you can find that Elvis Costello album on CD or MP3 download, you are probably better off than digitizing the cassette version. But rare and limited release albums were not always issued in CD format and recordings such as audio books, out-of-print material, children's books and bootleg concert recordings are not as dependent on audiophile quality. There are bargains to be had at estate sales and Half Price Books for used audio books and rare music tapes that can be transferred to play on your iPhone.
Outsourcing versus Do It Yourself
Converting tapes to digital files is not difficult but it can be time-consuming. If you have tapes that do not require high quality audio transfers, such as audio books, then you can use a Cassette to USB device. This is a small, cheaply-made cassette player than comes with a USB cable to connect to your laptop. Using a free program such as Audacity, you can transfer your tape content to a laptop and save it in MP3 or WAV file format.
For doing a high quality transfer on music recordings, you will need a good quality used cassette deck that, if working properly, will have much lower wow and flutter noise than a USB Cassette player. It will also have a much higher quality playback head that will capture a more accurate signal of your recording. In addition, Dolby noise reduction will likely be a feature on the cassette deck that will limit the tape "hiss"on your digitized file. Most of the pre-recorded music cassettes in the 1970's and 1980's were recorded with Dolby B. To get the benefits of this noise reduction, the tape must be played back on a cassette player that has Dolby B. More advanced versions of Dolby noise reduction are featured on more expensive decks including Dolby C, SR, S, and HX/HX-Pro.
Once you find a working cassette deck, RCA cables can be connected from the deck to a sound card or USB capture device on your PC or laptop. Another option is to connect a stereo patch cable from the MIC jack on the cassette deck to the line-in jack on your computer. Having a pre-amplifier and a good quality stereo amplifier will improve the sound being transferred from the cassette deck to the computer but is not required. Audacity software or similar audio capture software can be used on the computer to save the digitized audio.
Audio Digitizing Tips
Whether you are having a vendor perform the transfer or doing it yourself, here are a few things to keep in mind:
Remove Electrical Noise: Cassette recordings are an analog process so make sure you have an environment free from noise that can be picked up in the transfer. RF or power devices near your audio cables can result in static and pops in your digitized file.
Volume Optimization: If your cassette deck has volume meters, keep the volume needles out of the 'Red' zone that can cause distortion in your digitized file. A little 'Yellow' is fine but try to keep your volume needles in the 'Green' during playback.
Tape Head Cleaning: Before digitizing, especially on a used cassette deck, buy a cassette head cleaning tape and a cassette demagnetizing tape. These cleaning tapes will improve the sound on your transfer by cleaning the tape head(s), capstan and pinch rollers as well as removing the magnetic build-up that sometimes occurs on the tape heads. These cleaning tapes are still available on Amazon and eBay.
Left-Right Balance: Common sense tip but double-check that your left and right audio channels are even.
Bit Rate: When setting the bit rate on your capture software, 128 kbps is more than sufficient for audio books but consider using 256 kbps or 320 kbps for music recordings.
Noise Reduction: If you are digitizing a pre-recorded tape that has Dolby B, turn on your Dolby B feature on the cassette deck when transferring. Dolby HX and HX-Pro are available on higher end decks made from 1981 through the early 1990's.
Tape Hiss: Besides Dolby noise reduction, there is software that can reduce hiss. However, use these carefully as software filters can also reduce clarity and take out too many high frequencies in the recording.
Multiple Tape Volumes: If recording multiple tapes, they will often be at different volume levels. Try to keep the cassette deck at 75% volume level and check to see if you are getting a consistent volume on all digitized audio files.
Advanced Equalizers: Ask if your vendor is using a 31-band equalizer to enhance the highs, mid-range and bass on the cassettes as they are being digitized. Sound equalizers can vastly improve the quality of the final audio file.
Development in the late 1980's of the Digital Audio Tape (DAT) and the MiniDisc signaled the beginning of the end of cassettes for music. Sales of pre-recorded music cassettes in the U.S. dropped from 442 million in 1990 to just 34,000 cassettes sold in 2009. But there is still value and memories in those cassettes you have stored somewhere in the house. Whether tackling the project yourself or choosing a service company, take advantage of the technical advances that can bring those audio gems back to life.