I enjoy working with tape–reel-to-reel, cassettes, microcassettes, all of it. I get asked sometimes about how to reduce noise in making cassette stuff. First off, I kind of like the noise, it’s a part of the medium. But also in the heyday of these things people worked really hard to eliminate the noise. It’s the combination of working to eliminate the noise with the impossibility of that task which I find makes for an enjoyable and worthwhile challenge in using the medium. Here are some thoughts.
An 8-channel reel-to-reel recorder working on 1/4” tape will be using 1/32” of tape width per channel. A 4 channel Tascam on cassette will be using 1/32” of tape width per channel. A great amount of the noise inherent in cassette systems is in the electronics and mechanical issues (tape speed, quality of tape).
Here are the things I’ve learned along the way about handling tape hiss with cassette multitracks (in no particular order):
Clean and demag the tape head. No one ever does this. Whoever you bought the machine from definitely didn’t do it. If you haven’t done it then it probably hasn’t been done since it left the factory. It isn’t hard and it’s worth doing. Pick a number of usage-hours (10 hours) or a regular schedule (every 2nd Friday) that works for you and do it.
Use Type II tape. This kind of tape can take a hotter signal. It’s hard to find but one method I have found that yields results is to buy a large mystery box of random tapes or go to a thrift store. Once you have a bunch of tapes to look at find the ones that are obviously made as someone’s amateur vanity project—unknown middle-aged country performers or small vocal trios or classical solos. These often were made on Type II tape because the person was doing it for themselves and believed that the quality of tape mattered for the music; they got the expensive tape. You can see the difference by looking at the tape. Type I will look brown or red and probably be dull—it’s iron-based. Type II will be darker and probably shiny.
Run as hot as you can. The nice thing about tape is how forgiving it is to being “over” 0db compared to digital. Run it hot hot hot. The hotter you run the signal the more signal there is vs the noise. If you aren’t crossing over the 0db mark on the recorder regularly then you aren’t running hot enough. Again, experiment here. But err on the side of too hot. Learn where the distortion gets to be too much and stay just shy of that.
Speaking of running hot: the preamps on these things are noisy as hell. Many (including me) like them. But if you are trying to get a clean recording use a different preamp and turn the recorder’s preamp knob all the way over to “line.”
Dolby NR is usually not worth it. Instead, run signals with a gentle high shelf boost (pick a frequency, experiment, I tend to be between 800 and 1000). When you play back/mix use the same EQ & settings and cut by the same amount.
Try to avoid bouncing tracks. For example: If you are using more than 2 MIDI controllable things consider donating a track to SMPTE stripe and letting those MIDI instruments not take up channels on your cassette—record them as you master the cassette, letting them follow the SMPTE stripe. Or, if you can, record two instruments with one microphone (singers with a figure 8 etc) so you don’t have to bounce them– this helps keeps hiss from building up. Similarly, use a submixer to make a 1 or 2 channel drum kit mix instead of putting them all on different tape channels to bounce. It requires better mic placement and performances though so it might be a tradeoff that way. Every time you bounce you’re multiplying the tape hiss by the number of channels you’re bouncing.
Turn off channels you aren’t using so they aren’t adding noise to your mix. Usually not a problem with a 4 track because you’re out of tracks. But for the 8 channel cassette mixers this matters.
Often there is more hiss is in the electronics than the tape medium itself. Try testing different outputs. Between the headphone out, line out, monitor out jacks, one of them may have a cleaner signal. The Tascams in particular often have a blown vca in the headphone jack due to people running too many headphones from them via unpowered splitters.
Work at the “high” speed setting and also (if you don’t need it for other effects) set the speed of the adjustable pitch to high pitch. This will run your machine at the fastest possible speed, which makes the tape hiss go up in pitch (much of it goes up out of human hearing range).
Do all of that and then output as clean as you can into clean converter preamps. Figure out whether your converter preamps sound cleaner as a boost vs cranking the cassette mixer. Almost certainly running the mixer at a modest level and getting your gain from your converter will be better. If you can send individual tracks to your computer all at once (some of the Yamahas have an insert that works for this) this is better. Then you can mix and sum digitally or with a clean mixer.
When all that is done and you’re ready to get rid of the last bit of tape hiss, open up Izotope Rx Advanced, use the Spectral DeNoise module and train it on a couple seconds of noise at the beginning or end of your track. Set it on the high quality preset and use the “amount” slider until you like it. If you are worried about how much music you are sucking out of the track check the “output noise only” checkbox and if you hear any of your music in there reduce the “amount.”
Someone will eventually ask you why do you go through all of that? to record on tape. Have a simple answer handy like “I really like the tape process and working with my hands” or “I just always made my best stuff this way” or “There’s something magical about the light compression in the mids and the way this old cassette stock handles bass” or “here’s a copy of my latest tape, where can I find your music?”
Signal flow for removing tape hiss:
Clean mic preamp
EQ with high shelf boost N db
Cassette multitrack in (gain set to line or very very low)
No Bouncing, Just Mixing
Whichever output is cleanest between headphone/monitor/line/sum
EQ with high shelf cut N db
AD for final gain boost into computer (alternately a clean pre and then the AD).
Izotope Rx or other digital tape-hiss removal tool