So it looks like the guitar or bass can be easily recorded at home. Really? Guitarists, taking care of your signal path, let’s take a look at a few facts that might open your eyes wide. We are talking about the cables and their „sound”, and we miss much more serious matter…
No conclusions now, just the bare facts. We will think later. I decided to conduct a „survey” of guitars and basses in my studio, and discuss the results. The first test involving: Fender Stratocaster Made in Japan, Gibson ES335 Lucille (borrowed from a friend for a while, so it is on a separate photo) and Squier Precision Bass and Ibanez Soundgear. Strato, Gibson and Precision are completely passive, Ibanez is active, with „one-knob” EQ and bypass switch, that allows you to bypass the electronics or rather to bypass the EQ only, since bass does not work without battery. If anyone has any objections to the Squier and questions what it’s doing in this test, I will answer short – the best bass guitar in the world (SQ serial number BTW). All instruments are of legal age (only Lucille is a bit younger) and they can order a beer, they are not modern products. Both basses have a P/J pickups, although during recording I was using the precision pickup only. Strato was recorded using the bridge pickup, the Lucille… I do not even know what – because of the rotary switch, changing different things – of course I’m pretty sure that it was bridge pickup as well 😉
As you can see, ordinary guitars, nothing special.
I don’t have the any high-output guitar with active pickups – I will have to find such a thing, preferably including one good guitarist. Reamping is usually used in heavier music, such guitar will be needed for sure, but in order not to delay, I’m going on – maybe I will add a supplement later.
As the primary buffer I used a Boss CS-2 compressor – an indispensable device that accompanies me continuously since 1987 or 1988. I play with the compressor all the time, but that’s irrelevant – it is used as a FET buffer here, in bypass mode. Compressor input impedance is 1MΩ. Powered by a new alkaline battery. Cables – good, Mayones, Planet Waves and from friends from APS – if it makes any difference 😉
Yes, input is quite strangely connected with not so professional „thief” headphone splitter that is the cheapest passive splitter in the world 😉
All recordings were made using the Pro-Tools HD with 96io interface.
Now focus on, it will be difficult, it will be theory, decibels and volts. This interface is rather uncommonly calibrated, having its operating level -10dBV (or +4dBu) at -14dBFS, which results in a 2 dB more headroom than traditional interfaces calibrated at -12dBFS. To clip the 96io interface one need to have the signal that is 14dB hotter than the operating level (-10 or +4). The 14dB difference is almost exactly five times – gain or attenuation. To express that in volts, nominal effective input voltage on -10dBV is 0.316 V, which is the nominal peak voltage about 0.45 V. The interface will clip at five times the peak voltage, which is 2.24 V, or about 4.5 Vpp (peak to peak) . The most common consumer interfaces are calibrated to-12dBFS, what means that they accept without clipping about four times (12dB) greater signal than the nominal signal, it is less than 2V. Of course, remember that all connections and levels are unbalanced, it is the guitar after all. The input impedance is also an important parameter, it is more or less 10kΩ (unbalanced input).
Since the passive instrument loaded with 10kΩ impedance certainly does not sound well and the level will be rather low, I have set-up the buffer in which with the greatest precision possible I have set the unity gain. It is Focusrite Platinum Penta processor – I just had it in the rack waiting for job 😉 All processors and filters are of course bypassed, I used only the input preamplifier with instrumental input. For this test let me assume that this setup produces exactly the same level as guitar connected to a proper (at least 200kΩ) input impedance. I set the Focusrite output on +4dBu operating level, so as expected, I had to pad the instrument input a bit, about 12dB, more or less. I have checked that interface clips first, before the buffer clips, so that buffer is not causing clipping for sure. What we have on Focusrite output is buffered guitar signal – that is the level is exactly the same as the level a guitar amplifier receives directly from guitar connected with a cable to the amplifier and it does not drop when loaded.
Understood? Don’t worry, it’ll come out later. If you have any comments, please write a line or two. For now let’s assume, that the interfaces can accept and record (and then play) quite a high levels. Certainly no guitar nor bass can produce such levels, we have read about it many times, it will rather be millivolts. O’rly? Well, we’ll see…