Tips & Techniques
Technique : Effects / Processing
With so much interest in vintage synths, it's easy to overlook the fact that many classic sounds owed just as much to the tape delays being used at the time as to the instruments themselves. PAUL WHITE shows you how to fake the effect.
For little more than a couple of hundred pounds, you can buy a modern digital effects unit capable of producing dozens of different effects, often several at a time, and under the full control of MIDI. But it hasn't always been this way. With current musical trends owing as much to the past as to the present, there's naturally a great interest in recreating the sounds heard on record 10, 20 or even 30 years ago, which is why old guitars, guitar amps, analogue drum machines, analogue synths and so on now command very high prices. Certain effects units have also become very rare and expensive, and even if you can get your hands on a tape loop echo unit, for example, they tend to be very unreliable. There's no denying, however, that these effects do sound different to their digital counterparts, but if you know why they sound different, you can go a long way towards replicating the effect using modern multi-effects and a little ingenuity.
GETTING IT TAPED
Pretty much everyone is familiar with the Shadows guitar sound, and apparently it's still one that a lot of players try to emulate. Undoubtedly much of the sound comes from Hank's fingers, but that famous echo effect is fatter, warmer and richer than you get from a basic digital delay. Similarly, when used on a synth or string machine, tape delay adds a new dimension to the sound that's often missing from the more clinical-sounding, digital units.
A tape loop echo unit uses a continuous band of tape which moves first past an erase head to clean off the recording from the previous pass, then past a record head to record new material, then past two or three playback heads to play back the new recording. The delay is purely down to a combination of tape speed and the spacing between the heads and, just as on a digital delay, you could feed some of the output back into the input to create regenerating echoes.
The first step in simulating the original effect is to set up two or three delay taps to produce a mono delay where the three taps are not equally spaced. The actual delay time of the original echo units was set using a motor speed control, but start off by setting your delay times at around 100mS, 145mS and 190mS. If you have a delay that only allows you to set two different delay times, try using the 100Ms and 190mS times, and if you have only a single delay time setting, try something in between the two extremes. If you find the echo effect is too long for the type of music, shorten the delay times proportionally. The reason for selecting unequal delay times is so that when you turn up the feedback, the repeats don't fall exactly on top of the previous repeats. In other words, the complexity of the echo builds up with time, almost like a very coarse reverb.
LOW FIDELITY
That sorts out the delay effect. By turning up the feedback, you can set the number of repeats before the sound dies away, but at this point, you still won't have the warm sound of the original tape delay. The reason is partly due to the rather poor audio bandwidth of the old echo boxes -- if you could get 5kHz out of them, you were doing well, especially after the same tape loop had been on for a few days. This poor bandwidth created a warm, comfortable (though often rather noisy) sound, and every time a repeat was fed back to the input, it lost more top end and became more indistinct, which produced a rather nice, natural decay characteristic.
The other source of warmth was the extraordinarily high amount of wow and flutter, due to the crude transport systems used -- this resulted in a very subtle chorus effect being added to the sound. Both these effects can be emulated, but how you do it depends on the facilities at your disposal. Some digital effects units let you set a low-pass filter to use with delay effects, and in this case, simply experiment with values between 2 and 5kHz until you get the warmth you need. However, if there is no filter facility, feed the effect return into a spare mixer channel and use the high EQ control to roll off the top end. To maintain authenticity, you should resist the temptation to use the effect in stereo.
An even better option for adding warmth is to set zero feedback on the effect unit itself, but use the appropriate aux control on the effect return channel to feed some of the EQ'd delay back to the effect send. For example, if your delay unit is fed from the Aux 1 output, turn up the Aux 1 send on the effect return channel until you get the right number of repeats. Of course, if you go too far, the whole thing will run away in a rush of feedback, just like the old tape units did. Figure 1 (see page 244) shows how this effect is set up.
UTTERLY FLUTTERLY
To recreate the necessary wow and flutter, use the LFO modulation to cause the pitch of the delayed sound to waver very slightly. An LFO speed of between 3 and 5Hz should do the trick, but don't use too much depth or you'll end up with an obvious chorus effect.
What I've described may seem a lot of trouble to go to just to set up an echo effect, but it's this kind of attention to detail that can make all the difference between an adequate sound and a sound that's pure magic. The end always justifies the means when it comes to recording, and experimenting is half the fun.
CARRY ON AMPING
For those of you who like to experiment with microphones, you can get a delightfully authentic echo effect by feeding the delay output (treated according to the suggestions in this article) not back into the mixer, but into a guitar practice amp. Mike up the amp using your warmest dynamic mic and feed the miked signal back into the mix. You can even add a bit of spring reverb to the delays using the amp's internal spring system if it has one. Figure 2 shows how this works.
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