One of the techniques that make up the “Abbey Road Sound” is referred to, colloquially, as the “Abbey Road Reverb Trick.” Before we discuss the how-to, let’s talk about the results. If you listen to plate or chamber reverbs in their natural state, there’s a lot of information going on throughout the frequency spectrum. In short, the lows make mud in a mix, while the highs can result in oddly distracting, unnatural reverb tails (think ’80s-style ballad reverbs). In reality space, we don’t often hear such reverb decays, and certainly not as distinctly as when exclusively assigned to a particular sound in a loudspeaker mix.
You Do You, Glue
The Abbey Road reverb EQ technique not only prevents a track from swimming in reverb and thereby losing intelligibility, it also offers a means of gluing instruments and vocals together in a mix. It eliminates annoying high-frequency tails, increases clarity, yet still provides the sheen and size that reverb can impart to a sound. The trick is actually quite simple and works with any and every reverb unit; hardware or software. If you’re working with plug-ins, insert an EQ with high and low shelving filters ahead of the reverb unit. Position is important. EQ placed ahead of the reverb results in a smoother sound, since you’re equalizing the frequencies that are activating the reverb’s reflection algorithms. Since reverbs often accentuate certain frequencies, placing EQ after the reverb doesn’t have the same effect as taming the frequencies before they come in to the unit.
The essential part of this technique is to set the equalizer’s high-pass filter to a 12 or 18dB/octave slope and cut everything below 600Hz (that’s right, 600Hz). Set the low-pass filter with the same slope and cut everything above 10kHz. There you have it, the reverb EQ that Abbey Road has been using since the ’60s. However, you don’t have to stick with the high-frequency setting (the low frequency is not negotiable). You may find that cutting the highs down to 8kHz or 7kHz (or lower) works better on certain vocals or instruments in context. The idea is to reduce the highs until you can hear the vocal without the obvious high-frequency reverb tail. Another useful variation of the Abbey Road reverb EQ, in the case of vocals, is to notch out a tiny amount around 2kHz-4kHz, which will reduce possible harshness in the presence range. In the case of drums, you can cut highs further, even down to around 2.5kHz. It’s a very narrow frequency band, but it still offers all the benefits that reverb provides without adding high-frequency harshness (especially when there’s a lot of “metal-work” going on).
’Ear Now, What’s All This Then?
Unless you’re going for a special effect, such as the ’80s pre-delay followed by a high-frequency-rich tail (used most notably on percussion and snare), you can use the Abbey Road reverb technique on every instrument and vocal in your mix to achieve size, dimension, and blend. Above all, don’t be afraid to experiment. Start with the standard Abbey Road EQ settings at 600Hz and 10kHz and see where your ears take you.