I'm just starting to set up a small home studio with hopes of recording a small group I'm in. Strictly acoustic: ukulele, mandolin, clarinet, and flute (weird, I know). So far I have a Scarlett 2i2 and 2 mics: an AT 2021 (condenser) and a cheap SM57 clone (dynamic). I've done a little playing with the system and recordings sound ok so far, but I have the gains cranked up pretty high on the AI, especially the one for the dynamic mic. I'm wondering if a di box (or 2) would help with this.
Repeat: no pickups on any of the instruments. Any suggestions, or alternative ideas?
George
Hi George,
Typically a DI box is used to convert an unbalanced (think guitar cable) to a balanced (think XLR-to-XLR mic cable) in order to combat hum from ground loops, and/or EMI and/or RF interference for longer cable runs.
If you have everything miked up and are using all XLR-to-XLR cables (and NOT XLR-to-1/4" 2-conductor cables) from your mics to your Focusrite Scarlett 2i2, you should not have any hum unless your are running your mic cables less than 6" away from AND parallel to A/C power cables (which might still introduce a 50hz/60hz audible hum into your signal), but in most cases, a DI box would be completely obviated by and duplicated by the XLR inputs on your Focusrite Scarlett 2i2.
Some of these interfaces have a cut/boost or PAD switch that lowers or raises your input gain by a fixed 20db. On the Scarlett 2i2, it seems that this function might be handled by the '2 Line/Instrument switches' on the front panel.
While the primary function of such a switch would be to handle the difference in impedance between the guitar signal (typically 1kilo-Ohm @ around 700 millivolts) compared to a mic signal, which can vary from 600ohms to around 150ohms depending on the specific mic, and it's sensitivity rating, and an output voltage typically of 1 volt) - [what the switch does is tell the internal circuits of the preamps inside, how to react to whatever is plugged in, in order to provide a proper signal level and impedance to the A/D converter with enough gain, and without overload (distortion)]...
You might want to try and futz with those switches and verify that you have them set in the MIC position when your MICs are plugged in. Do this with the power off, otherwise you could damage your microphones if phantom power is on (some condenser mics are very sensitive).
Having said all that, I too have had this very same problem with the gain being too low, and have done TONS of research and testing on it myself.
I have found a solution that works well, but you have to be careful to try and maintain 'UNITY GAIN' in my recommendation below, otherwise you will introduce noise and distortion and can overload and burn out the input circuits of your Scarlett interface.
I have a similar interface that I use, made by
Applied Research & Technology (A.R.T.) called the 'USB Dual TUBE Pre'. Make note that they have several similar interfaces, and one named almost the same that is NOT a 'TUBE' preamp, but the one I have is the
TUBE version.
Whether I have a dynamic mic, such as the
E-V N/D767a or a studio condendser like the
AKG Perception 200, the level is too low (-10db) to get a good recording. You want your level to be somewhere around -6db to -3db with enough headroom to 0db without clipping (distortion).
My solution was to stack another preamp inline, BEFORE the interface. I already had 2 different mic preamps. the one I use for the E-V mic is an
M-Audio 'Audio Buddy' 2-channel solid state unit (~$69) and for the AKG mic I use a
Behringer MIC200 tube preamp.
Each of them 'claims' to be able to provide up to 80db of gain. The actual amount at this level is unimportant since a 1db gain is TEN TIMES louder.
By using each of these items, with the level controls set to 12 o'clock, i.e., half way up, and the A.R.T. preamp's gain to around 11 o'clock and master faders to 12 o'clock, I am able to feed the computer (or iPad) with the proper signal that is plenty loud enough for a good recording level in the range as I mentioned above. While I have no real way to measure UNITY gain with these pieces of equipment, I can use my ears to hear when if I turn up the levels even a bit past these settings, the recording starts to clip a little if I do not engage the limiter function built in to the hardware interface.
The caution here is that on the Behringer MIC200 there is a level for the TUBE preamp, and then a level for the output. If I set the preamp level higher it saturates nicely with some tube warmth, but you have to lower the OUTPUT level to compensate, and if you do the opposite, as in lower the pre level, and crank the OUTPUT level you end up introducing the unit's unwanted circuit 'self-noise' into your signal path, which is typical of most preamps that cost less than $500.
But the caution here is that you have to start with the levels LOW on both these preamps, and in your case your Scarlett 2i2, and monitor the levels (in headphones and
NOT speakers, otherwise you will get deafening feedback), and slowly raise the gain of the external preamps, and then the interface until you have an acceptable signal level.
There is some trial and error involved, but it should not take more than 20 mins of testing to find a good level. You can make some test recordings and see what the level is in db (decibels) in your software and if you can keep it above -6db but not higher than -3db you should have a very nice sounding recording. Anything that consistently peaks at 0db or higher will be distorted and sound terrible.
Behringer also makes a model called the MIC100 that does not have the selector switch for the different built-in EQ curves that is typically about $10 cheaper, so if you don't want/need them, you can save some money. I have found them useful, especially for the ukulele.
They also make a dual tube preamp, that is a standard 19" rackmount unit but it has been getting really bad reviews, and some say that the sound is very bad due to the fact that BOTH input channels are going into a single tube inside, instead of each having their own tube, and this causes phase cancellation and other problems that just sound bad.
You can get the Behringer MIC100 on
Amazon or
Sweetwater.
Also, just in case it is not clear yet - your signal path should look like this:
- Mic into Behringer or M-Audio input (preamp) (turn on phantom power for the condenser mic)
- Preamp output into Scarlett 2i2 input set for MIC
- Scarlett into computer & headphones
I realize that there might be lots of technical info here for the uninitiated, and if you need me to clarify anything further or have any other questions, I'd be happy to help.
The simple takeaway from all the above is that you can get 2 INEXPENSIVE single-channel preamps for less than $100 shipped, and put them between your microphones and Scarlett 2i2, and unless there are evil gremlins near you at all times, it should solve your problem, as it did mine.
I am in fact in the process of recording my first album right now using the setup that I have described above, so these are not some wild recommendations from just reading about it in audio magazines, I am truly 'eating my own dog-food' here.
I have had a home studio in various forms for at least the past 25 yrs, and was a part owner, sound tech and DJ in a Mobile DJ and live sound reinforcement company, and while I have never 'worked' as a professional sound engineer in a fancy studio, I do have a modicum of experience in what is necessary to get good CLEAN sound without taking out a second mortgage to pay for all that esoteric equipment.
Please let me know if I can offer any further assistance.
-Booli
