close-mic'ing bass amp

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matt rascal

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I've always DI'd my bass, but i no longer have my direct box. I'm using a Carvin solid state amp (1 15" speaker, not sure about the wattage). My plan is to mix the line out signal (which doesn't sound good enough on its own) with a mic (probably an sm57). I have never done this before, so...
How loud should the amp be? quiet, meduim, etc
and do you guys have any tips? mic placement/anything

thanks!
 
It should be loud enough to get a decent signal and not so loud that it's clipping. Try to get the volume where the amp sounds "best" and adjust your preamp gain accordingly.

As for where to place it, you'll have to move the mic around to find the best place for the speaker. In my experience, you should have the mic out at least a foot from the speaker for bass for a more balanced sound.
 
One interesting tip that I have heard is to try micing the bass itself, the actual instrument. It can add some cool and unique sounds. Its pretty sweet, but the sound may not work for all bass sounds. Just an idea. :D
 
Be careful mixing your line and mic'd tracks. Electricity travels slightly faster than sound... so your line and mic tracks may have fun phase issues. If you're using a DAW you can zoom way in and slide one track the back or forward to get them back in phase.
 
Also keep in mind that the SM57 is not known for its strength in the bass frequencies. If a 57 is the only mic that you have to experiment with on your bass amp, you might not be satisfied with the results. You'd have much better results with a mic that does well with these lower frequencies, such as the mics that people often use on bass drum (the AKG D112, the Beyer M88, the Audio Technica ATM-25, etc...)

But, as always, YMMV. Lots of luck!
 
Chris Shaeffer said:
Electricity travels slightly faster than sound...
Click to expand...
That is a mild understatement. Electricity travels almost as fast as light which is a little more than 'slightly' faster than 700 some-odd mph
 
Farview said:
That is a mild understatement. Electricity travels almost as fast as light which is a little more than 'slightly' faster than 700 some-odd mph
Click to expand...
well electricity moves as fast as the electrons do :)
 
At least no one thinks that what goes through a mic cable is sound, not electricity!! :rolleyes:
 
An old friend of mine encountered the first fax machine we installed in the office. He was a crusty cigarette-and-bourbon lawyer from the old school and still didn't trust electric typewriters, much preferring a young stenographer on the lap.

Anyway, we hooked the thing up and all began to use it pretty much full time from that moment on. He finally shuffled over one day with a document to fax and muttered "How the hell do you use this thing?" whereupon one of the staff explained it in great detail and helped him send the fax.

He was duly impressed when he heard the line ringer and all the little noises. Then he spied his original and said "Well, if this thing's so great, would you tell me what the hell that is still doing here??!!"

:D
 
$a1Ty said:
well electricity moves as fast as the electrons do :)
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Which would be a lot closer to the speed of light than the speed of sound, don'cha think?
 
tourettes5139 said:
At least no one thinks that what goes through a mic cable is sound, not electricity!! :rolleyes:
Click to expand...

In the space between the speaker and the mic its sound. I don't care how close you mic it, there WILL be a difference. Try it.
 
Lets say electricity through a cable is negligible, placing a mic out by about a foot has a delay of ~1 ms.
 
I hate to interrupt, but...

do you guys think a 57 would be a bad choice? I don't know why, but I thought I had heard of it being used with recording bass.

As far as dynamic mics go I have an e835, some cheap akg live mics, and two or three more sm57s :-).

Thanks everyone!
 
i've recorded bass with a 57 and got great results with it.. if it's all you've got i'm sure you can get a decent sound using that mic. it's not a "bass mic" per se, but whatever..
 
a_zander said:
Lets say electricity through a cable is negligible, placing a mic out by about a foot has a delay of ~1 ms.
Click to expand...

1 ms isn't much, is it? I actually wouldn't worry about it much at 1' out. At that point you're probably past the 3-1 rule.

If you don't know what phase cancelation is then don't worry about it. Most of the time you'll say "Wow, it sounds worse with the DI on. I'll just mute it." Or maybe you won't notice any trouble at all.

If you are curious about phase & phase cancellation:

"Phase: the relative measurement of a period of time referenced to the start point of a cycle of a periodic waveform. In one complete period, a wave's polarity fluctuates 360° (180° positive and 180° negative). Absolute phase is a reference point in time within one cycle—e.g., halfway through one period, the waveform's phase is 180°; at one-quarter of the waveform, the phase is 90°. Relative phase is an instantaneous ("snapshot") measure of the difference in time between two acoustic or electronic waveforms of the same waveform and frequency. For example, if one waveform is one-quarter of the way through its cycle (90° at its peak positive value) and the other is three-quarters of the way through its cycle (270° at its greatest negative value), they are 180° out-of-phase with respect to each other. The two signals are "in-phase" if their amplitudes are identical at the same point in their cycles."

"Phase Cancellation: an attenuation of signal components resulting from combining out-of-phase waveforms. When two waveforms are mixed, their harmonics are added. If the signals are out-of-phase with each other, then the amplitudes of the harmonic components differ at various times (as determined by the phase relationship). If the added harmonics have the same polarity, then the signal is reinforced at those frequencies. If harmonics with positive values are added to harmonics with negative values, then the signal is attenuated (canceled) at those frequencies."

From http://mixguides.com/studiomonitors/Basics/audio-glossary-basic-monitors/

So if your DI track and miced track are just a tiny bit out of time with each other (i.e. out of phase) you could have some wierd frequency shifting going on.

Anyway, I probably should have explained that all in my first post. This is part of the "engineering" aspect of audio engineering. Sorry if it ended up distracting from the thread, Matt, but I was responding to your stated plan of mixing line and mic signals for your bass. Chances

A 57 will work for bass, sure. Keep in mind the 57's frequency response, though.
See it here..

It rolls of the low frequencies starting at around 200hz. You can still get a good sound out of it for bass, but that's why it isn't considered a bass mic. I couldn't find a link the the e835's frequency response graph, but you can download a PDF with it here.

It looks like the e835 has *less* low-end rolloff than the 57, so I'd try it first.

Placement?

http://www.soundonsound.com/sos/oct01/articles/bassrecording.asp
http://industryclick.com/magazinear...easeid=5577&magazinearticleid=65436&siteid=15

I found the links at The Project Studio Handbook site.

Have fun!
Chris
 
Chris Shaeffer said:
In the space between the speaker and the mic its sound. I don't care how close you mic it, there WILL be a difference. Try it.
Click to expand...

Yes, of course there will be. I have had it happen to me, there is a definite difference. My post was just poking fun at an individual a week or so ago (I think) that was arguing that it is sound that travels through cables, not electrical signals. Thats all I meant. I think I missed the part in your post about the phase differences between mic'd and DI signals when I was posting. I didn't mean to be argumentative. Sorry for the confusion. :D
 
Sorry, Tourettes. I did mistake your post. :rolleyes:

Perhaps I shouldn't be using the BBS as a distraction when I'm irritated at work?

:D

Take care,
Chris
 
Don't worry about it. It was partly my fault, too. And by the way, I use this board for distraction when I am irritated during my American History lectures. ;)
 
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