There’s a lot of musical equipment that doesn’t operate as quietly as we’d like for it to in a recording situation. This may be due to bad circuitry, old technology, high impedance signal output or a number of other things. Some analogue equipment is inherently noisy, but at the same time, the effect is so pleasing in comparison to the newer, quieter (and yes, colder) digital equipment that is being produced, that we’d prefer to use it nonetheless. I know how this feels, as I have an old Wurlitzer WX40 synthesizer that I’ve grown very accustomed to using. It is an analogue unit, and quite old.. one of the first of it’s kind, actually. It’s cool. And noisy as hell. I have still found a way to use the device in a recording situation and have configured it in such a way that the noise is either nearly lowered to the level of the noise floor or else masked through complimentary blending. Maybe I invented this last one out of desperation, but it works rather well.
A few things can be done to first insure that our setup will run as quietly as possible. If we’re not thorough, however, we can be left pulling our hair out, so allow me to sidebar here to cite many culprits.
Sometimes AC power supplies, DC adaptors or “wall warts” can spike the line with a great deal of noise. All these little boxes contain is a transformer which converts the AC voltage to DC voltage. The excess voltage is converted into heat and noise. How much? Take a cheap transistor AM radio and tune it to a vacant frequency. Now, with the volume up a bit, gradually move the radio to within an inch or so of one of these transformers. That is the noise that we are having to deal with. The amplifier in the radio does magnify this noise, but then this is a great way to check for all kinds of extraneous racket. Just move the radio all about the room, the walls and all of the equipment. If there’s a noise spike you’ll locate it!
We mustn’t overlook fluorescent lighting, either. This crap may or may not help the environment, but it will most definitely ruin recordings. The noise that these things generate is huge. Use only incandescent lighting in and around the studio. For that matter, any appliance, transformer or lighting fixture that is running on the same circuit breaker or house fuse may inject hum in your recording equipment, even if it is in another room. We’ll want to check that this circuit is clean.
Make sure that the outlets are grounded. Most homes these days have three conductor outlets and the ground must be intact. We do not want to use those little adaptors that convert our three prong plugs to two prong usage. Nor do we want to snip of the third prong of our AC lines running to our recording equipment. I won’t go into grounding here, because the post would be excruciatingly long, but now that I think of it, it is something that I will undoubtedly need to address in another installment. If your home doesn’t have grounded outlets, you will need to at least have the outlets to your equipment grounded or else you aren’t going to have much fun recording. For now, the only advice that I can give is that you call an electrician.
Assuming the outlets are grounded and all noise producing appliances have been eliminated, lets move on to our recording devices and effects. Effects can be powered either by AC voltage, those bloody transformers, batteries, or in some cases phantom power. Sometimes the transformers can be moved far enough away from the recording gear to eliminate the noise, we just don’t want any of these things lying near the equipment. If you can hear the noise through the headphones, and it can be remedied through the use of batteries, by all means use the batteries. You’ll go through them, I know, but the DC current produced by them is noiseless. A lot of effects are high impedance devices, that is to say that the cables employed by them have TS (tip/sleeve) connectors. Instrument cables, in other words. (We don’t want to use cables that were intended for PA speaker use. They are cheaper, true, but we don’t want to skimp on cables. Speaker cables are completely different because they are not shielded. They will be another source of noise, too, and this is what were are trying to avoid.) Guitar effects fall into this category. If you happen to have a beloved effect pedal that generates noise within the unit, you can use a DI (direct input or direct injection) box. These units take the high impedance signal and convert it to a low impedance signal. The line coming out of these boxes is the XLR type. Most serious recording gear has XLR inputs and outputs. If I am recording an instrument direct, a guitar without the use of an amplifier, or my keyboard, I will always use a DI box. (keys are notorious for high impedance outputs.) The XLR signal will be surprisingly quieter: the noise is taken care of through an electrical anomaly called phase cancellation, wherein the +noise is combined with the -noise and the result is no noise. Very, very cool.
Sometimes, however, the noise encompasses such a broad frequency spectrum, it makes itself evident everywhere. This was the case with the aforementioned Wurli. And this is how I took care of it: First I fed both high impedance channels into separate DI boxes, which were active, or powered by 9V batteries, rather than the passive types that can be used for guitar amplifiers and such. This signal was then fed into a dual 31 band EQ and then I ran both channels into a dual channel compressor which gave me the option to bridge both channels for stereo use. This way, adjustments made to one channel automatically adjust the other. The doctored L/R signals were then patched into my eight-track recorder. Following the same procedure for EQ and compressor adjustment as outlined in my earlier installments, the results were astounding. But the noise gate was cutting off the tail of my signal!
You may be wondering, at this point, why I didn’t just go out and get a digital keyboard. Several reasons, in fact: The Wurlitzer was a gift from a client, it was a first generation synth (a collectors item.. these babies still book at around $1000.), and it was analogue and, quite simply, I’m queer for analogue equipment. Well, the solution was as simple as routing the signal out the back of the recorder, via an insert point and into a small stereo reverb unit. I adjusted the reverb to where the volume was just above that of where the noise gate shut. The reverb tail was sweet, natural sounding.. and faded into silence!
Remember the Russian proverb: Necessity is the mother of invention.
I suppose that in the next chapter, I’ll discuss grounding, being your own electrician, and not getting fried.
Happy trails until then.