On an analog tape recorder, as the tape moves from one reel to the other, it passes through the tape path, which contains a record head and a playback head (aka repro head), both of which are electromagnetic components that are essential to the recording process. Some tape machines have three heads: record, repro and a separate erase head.

The record head takes the incoming audio signal and turns it into a pattern of magnetised particles. These particles, with the help of magnetic radiation called flux, adhere to the tape in a pattern that’s an analog (a replication) of the soundwaves in the audio signal. Hence the term, “analog recording.”

When the tape is later played back, the playback head reads the pattern of magnetised particles as the tape passes by and turns it back into an audio signal.

One of the significant variables of tape recording is the speed at which the tape moves through the tape path and across the heads, measured in inches per second (ips). The faster the tape speed, the better the high-frequency reproduction. Slower speeds offer a slightly better low-end response, but because of their inferior high-end reproduction, generally sound more “lo-fi.”

On tape emulation plugins you generally get some tape speed options. For example, on the J37 Tape plugin, modeled from a Studer J37—the same 4-track recorder used at Abbey Road Studios during the Beatles era—you can choose either 15ips or 7.5ips. For a more hi-fi sound choose 15ips, and for a little bit more grunge use 7.5ips.

Different brands and types of tape were manufactured with different chemical formulations, causing them to behave and sound slightly different from one another. Some were cleaner, some offered a better high-end response.

On the J37 plugin, you can choose between the EMI 888, 811, and 815. The 815 offers the best quality, and the 888 is the lowest. Again, which one you pick depends on the sound you’re going for.

Another parameter you’ll see on tape plugins is called bias. On an actual tape machine, bias is an ultrasonic signal that’s introduced into the recording to help maximize the fidelity—particularly the high-end response. Tape recorder manufacturers typically offered recommendations for what bias settings to use with each of their machines.

Using the incorrect bias amount could cause degradation to the sound, but some engineers felt they could get a better sound by “over-biasing:” applying more than the recommended bias amount.

On a real tape recorder, wow and flutter are typically undesirable side effects of the machine’s mechanism. Wow is the term for the subtle frequency modulation caused by inconsistent performance of the machine’s motor. Flutter is caused by the tape’s infinitesimal up and down movements as it goes across the play head. The better quality the tape machine, the more precise its components were, and the less wow and flutter you would get.

Wow and flutter can be simulated in tape plugins. You’ll probably leave them off most of the time. Though if you’re going for absolute realism, you can dial them in at low levels. For creative modulation effects, turn them up higher.

One of the most significant disadvantages of recording to analog tape is that you can end up with a lot of background noise, because tape recorders have significantly lower signal-to-noise ratios than digital recorders do. If you record at loud enough levels, the audio masks the low-level noise. If you don’t, you’ll hear tape hiss. The signal-to-noise ratio specification, expressed in decibels, is a good predictor of the noise levels; the higher the number, the lower the noise.

Many tape emulation plugins include switchable tape noise. Like with wow and flutter, turning on the noise can be useful if you’re going for absolute realism. Otherwise, you may want to leave it off.

The first time delay effects were used in studios, they were created with a pair of tape machines. A track was played from one machine, split at the console and sent to a second machine, which was put into record mode.

Because the playback head was physically after the record head in the tape path, when monitored from the playback head of the second machine, the signal was delayed. It could then be blended back with the original recorder at the console to create a delay effect. Because the delay time was a function of the distance between the heads, the only way to change it was to switch the tape speed of the second machine.

As you may expect from a modern plugin, authentic tape delay sounds are available in the J37.

In digital recording you have to be very careful of your levels; if you go over 0 dB, you’re likely to clip the waveforms, resulting in a nasty-sounding distortion. An analog tape recorder, however, is much more forgiving when you go into the "red."

Instead of the unpleasant sound of digital distortion, you get a natural compression and distortion that’s referred to as tape saturation. Engineers use this to their advantage on drums, vocals, guitars—you name it—to add a warm crunchiness to the recording. The more you overload the input, the more saturation you get.

In the J37, you can saturate in two different ways: One is by overloading the input. The plugin has a button called Level Link, which is on by default. When you turn up the Input level, it reduces the Output level by an equal amount. This allows you to “hit” the input hard to create saturation without the plugin's output level changing. The J37 also has a separate Saturation circuit that can be controlled with a knob.

The master buss is a productive place to use a tape plugin. If you’re trying to give your entire mix a little subtle warmth, inserting a tape plugin on your master can take a bit of that digital “edge” off and make the whole thing sound more pleasing.

Typically, you don’t want to saturate too heavily on the master buss. Start by opening the plugin in its default state, and just listening to what that sounds like. Try experimenting with tape speed, bias level and different tape formulations to see how they affect the sound.

Next, try turning up the input slowly to create some saturation. Once you hear audible distortion, you’ve probably gone too far; so back it off until just before the point where it sounds distorted.

One of the main reasons some producers still record basic tracks to multitrack tape is the sound of tape saturation on the drums. You can emulate this with your tape plugin in a couple of ways: One way is to buss all the drums to a sub-master and insert the tape plugin there. Alternatively, you could insert an instance on all or some of the individual drum tracks and go to town.

Either way, check out the sounds of the various tape speeds and formulations. You might find that lower speeds add nice grunge.

You can fatten up a vocal nicely with a tape plugin. Be sure to listen to its effect throughout the entire track, because vocals tend to have a wide dynamic range and can get really loud in a few places. You may have the perfect saturation applied on, say, the verse, and then when you get to the chorus, it hits the plugins input louder and causes a distortion that you might not want. This could also happen when applying tape saturation to a full mix, and is something you should be on the lookout for.

To handle the volume fluctuations, whether on an individual track or full mix, try automating the tape plugin’s input level, bringing it down during the parts where the signal is too loud.

Using the J37 Level Link feature, the input and output compensate so that you can manage the amount of tape saturation while keeping the plugin's output the same. If your tape plugin has delay, try dialing in a little slapback (80-150 ms) on the vocal. Depending on the musical style, it can be a cool effect.

If you have synths that are a little too digital sounding, some tape saturation can give them a more analog vibe and make them sit better in the mix. It's your call whether you want to really fuzz it out or use more subtle settings. You might want to experiment with the wow and flutter, too.

Tape emulation can sound good on virtually any instrument. If you want ideas for starting points for your settings, it’s always worthwhile to check the presets that come with the plugin, as there might be one that’s specific to the instrument you’re working with. But remember, even though a preset is programmed for a specific type of source, it’s still somewhat generic. So, use it as a place to start, a place to get ideas for a direction for the settings, but then listen and tweak it to make it work best for your audio track.

Tape emulation plugins are potent tools for mixing. They can give you everything from subtle saturation to all-out distortion. As with any effect, you can overdo it. If you insert it on a lot of tracks and/or busses and are saturating all of them, it could muddy up your mix, so use it judiciously.

Do a lot of comparing of how the mix or track sounds with and without the effect, and let your ears be the judge. Used carefully, tape plugins can warm up sterile digital recordings and add some cool retro vibe. They're a powerful sonic tool to have at your disposal.

Article Courtesy Mike Levine. Waves.com 14 June, 2018