Recording an Acoustic with a Mic - Level Way to Low...

[JimF]

I've been recording with a friend for a while, all self taught, self produced kind of stuff. I've no doubt that I'll be using the wrong terms below, but he knows what he's doing.
Recently we decided to use an acoustic for a few parts rather than clean electric, that sort of 'Fight Fire With Fire' type cliched metal intro.
We're using Cubase, an SM57, an active DI box, and an interface.
With the mic literally about 1/2" away from the strings over the soundhole, playing fingerstyle was barely registering. The acoustic is loud enough for normal use so its not the guitar. By the time we turned up to match the levels of the other tracks, the background noise & hiss was so loud it was unusable.

Things we tried:
Using an SM58
Playing as hard as possible
Using the Db lift button on the DI box
Cranking all the volumes/gains

Things we can't try:
Plugging it in (non electric)
Using a different acoustic (we don't have one)
Putting the mic any closer
Upping the gain any more.

What are we missing?
To add context, we then proceeded to un-press the Db lift button on the DI box, and record vocals for the following two days without issues, so its not like something is broken.

It feels like there's some really obvious thing we're missing, its almost like when you plug your guitar into a PC without an interface and it sounds really weedy and thin. Except it can't be that.

 

[TedEH]

My first question is why is a DI box being used for a mic? A DI box is generally for taking an instrument level signal and plugging it into something expecting a mic signal. A mic signal is already a mic signal, so it doesn't need a DI box.

I've seen some dynamic mics requiring a gain boost (like a cloudlifter), but these are very different than a DI box.

 

[ArtDecade]

I've seen some dynamic mics requiring a gain boost (like a cloudlifter), but these are very different than a DI box.

I use lifters with ribbon mics. That said, I would just put the SM57/58 direct into the interface.

 

[Drew]

I've heard a SM57 used on an acoustic to interesting effect, but it's certainly not a traditional sound for an acoustic, and as you're discovering it's not especially sensitive and has a little bit more self-noise than is ideal for a quiet source like that. Do you have any other mics you can use? Some sort of condenser is usually the way to go here.

 

[JimF]

My first question is why is a DI box being used for a mic? A DI box is generally for taking an instrument level signal and plugging it into something expecting a mic signal. A mic signal is already a mic signal, so it doesn't need a DI box.

I've seen some dynamic mics requiring a gain boost (like a cloudlifter), but these are very different than a DI box.

I use lifters with ribbon mics. That said, I would just put the SM57/58 direct into the interface.

In that case I've most likely remembered wrong and we only used the DI box for guitars.

I've heard a SM57 used on an acoustic to interesting effect, but it's certainly not a traditional sound for an acoustic, and as you're discovering it's not especially sensitive and has a little bit more self-noise than is ideal for a quiet source like that. Do you have any other mics you can use? Some sort of condenser is usually the way to go here.

I'm sure he has a condenser mic, but we predominantly setup for doing vocals, not instruments unless they're DIs.
Is there an industry standard accoustic instrument mic? Or just any decent condenser?

 

[Winspear]

If you were running through a DI box, that would definitely mess with levels, regardless of if a lift button was on or off. Fingers crossed that is the issue, because it's a very obvious one in an area where I can see absolutely no other reason to have such a noticeable issue.

 

[c7spheres]

You can just record it at the best level you can get then try normalizing it if it's just a rough thing. Might come out good. Not a fan of it but it could work. Sounds like something to do with your preamp or interface settings. You using an actual preamp in the chain?

 

[JimF]

To the best of my knowledge, there was no physical preamp. Perhaps that's why we used the DI box? Let me call him and get the info lol.

 

[c7spheres]

To the best of my knowledge, there was no physical preamp. Perhaps that's why we used the DI box? Let me call him and get the info lol.

Some acoustics have pickups but no preamp but even with a DI box or mic you'll want a preamp for boosting level. Not all acoustics even with their preamps push hard enough. MIc you want one for sure. Most interfaces have them but some have level switches that could be set wrong like +4 or -10 button or mic/ line etc.

edit. make sure to turn all phaontom power options off unless using a condenser that needs one.

 

[JimF]

Acoustic is a billy basic non-electro.
I've spoken to him, and saying the DI box being involved was my mistake. It was mic into interface, which has a preamp inside it.

 

[Drew]

I'm sure he has a condenser mic, but we predominantly setup for doing vocals, not instruments unless they're DIs.
Is there an industry standard accoustic instrument mic? Or just any decent condenser?

This is one of those personal flavor things. Personally I usually reach for a sE Electronics 4400a, which is a modern take on a brass capsule AKG C414, but that's largely a product of what options I have. A C414 is definitely a popular choice, but this is kind of up there with "which pickups" or a question like that. Some sort of large diaphragm condensor is basically the "use a humbucker" level of answer, though.

 

[LiveOVErdrive]

Mic direct into the interface should be plenty loud. I use a 57 for Skype sometimes with it feet away from my face and it picks up just fine.

Maybe a volume setting in the interface software? Is it set to line level or something?

Bad cable maybe?

 

[JimF]

We changed the cable and all was ok.
Only thing I'm thinking it could be is like you said, volume set to line level on the guitar track.
We're going to have another crack at it in a few weeks!

 

[valvefury]

Definitely the type of mic you use is very important - a 57/58 is not ideal.

WHERE you place the mic is also important. Try placing the mic about 1" away from the 12th fret - when I record I do a stereo pair on the 12th fret

lbj

 

[Winspear]

Definitely XLR>XLR cable? XLR>TRS end into the interface will disengage preamp and assume line level, often

 

[JimF]

Definitely XLR>XLR cable? XLR>TRS end into the interface will disengage preamp and assume line level, often

I think we've found the issue! Tom you are a hero. Thanks everyone!

 

[TedEH]

I've used a 57 to record an acoustic right into a cheap interface plenty of times and it was plenty loud. Especially if you point right at the sound hole (which you shouldn't do), you'd get plenty of signal.

If you've got a variety of mics to play around with, IMO, a small condenser does acoustics well - you get a lot more detail than with a 57. And you can usually crank the gain up enough so that you don't have to be right up in your strings. I've got good result with a matched pair, sitting close to the floor in front of me and angled up - one pointed at the body and one pointed at the neck. Gives a bit of stereo image, and because you're not right up close, you don't have to fight with staying in exactly the same place as much, or dealing with proximity effects, etc.