Using Condensors Live.. UPDATE

[adamlutley]

Continuing on from the discussion re using condensers live..
Most of the conversation has concerned miking acoustic bass, so I thought I'd write more about this.
On Sunday I engineered a jazz ensemble.. The acoustic bass player requested I use an Rode NT3 on the bass which I found a little surprising.. anyway, for the first set I used the NT3..
I had to change to an SM57 for the 2nd set.. with the NT3 there was far too much spill from other instruments, particularly drums.. even with the NT3 very close to the the F Hole, there was just too much other stuff getting in there..
The SM57 was much more well suited to the task. The acoustic bass sound was quite soft so I needed to gain the mic a little.. with the 57 I wasn't as susceptible to feedback, whereas the NT3 was very sensitive.
I will be trying to get hold of an EV RE20 for my next mixing gig.
Please tell me of any lessons you have learned when miking double bass live..
I will be starting a dedicated topic on it which you will see straight after this one.
Adam

[87PRS]

yep....that's the same lesson I learned

[GZsound]

Yeah... One of the best upright bass sounds I have heard is on the bass of a guy that owns a local music store and can pretty much put any mic he wants on his bass.

He built a padded wooden "C" clamp that held a 57 pointed at the F hole.. sounded great.

[Drawmer]

One of my fav mics to put on a db bass is the MD441, it has a super tight pattern, so a can crank the gain more with confidence, I came to this after experimenting with an arsenal of mics.

[GZsound]

One of my fav mics to put on a db bass is the MD441, it has a super tight pattern, so a can crank the gain more with confidence, I came to this after experimenting with an arsenal of mics.

I haven't used a 441 but did try a 421 with poor results. I keep going back to my trusty SM58 "stuffed" behind the string guard since that's quick and easy and seems to get the best results when used for a variety of different basses during the course of a festival sound gig.

I have tried my RE20 on bass with mixed results. A better mic is an AKG D112 placed close to the bass. It will pick up the bass with pretty good off axis rejection.

I have been forced to use my AT 4047 on an upright bass one time (the band required it), but that was a disaster, Everytime the bass player moved his bass, the reflections from the instrument into the monitors caused huge problems.

[sabianq]

i have a question for you, is your system capable of reproducing the bass frequencies?
in most cases, if you do not have a dedicated bass cab and power amplifier, then it has been my expirence that the engineer should not actually mic the Electric Bass (unless the bass players personal cab is not sufficient to fill the room with the aproiate SPL) but a really good acoustic trick is to set the bass palyer,s cabinit behind the band aginst the wall or even better situated in the corner of the room, which naturally can amplify the SPL of the cab nearly 10db.

the band i work with has a very loud bass player and rarely di find the need to actually mic the bass, but when i do need to mic him like when I'm in a very large room or playing outside, then:

I use the AGK c 535 condenser exclusively and a low pass filter. position the microphone in between the center and rim of the driver. set it about an inch from the grille. if your cab has many drivers Like 4 10inch drivers then you should set the microphone center of the cab about a foot away, imagine looking at all four speakers from the vantage point of the microphone, you should be able to see the domes of the cones on all four speakers at the same time 'barely'.

[sabianq]

for an acoustic bass, use the microphone and aim it at the rim of the instrument from the position of the F hole as GZ suggested but point it more toward the edge of the instrument. the instrument acts as a resonant cavity, and the better quality of the instrument, the better the transmission of the sound throughout the instrument, the entire instrument moves to form the modulated low frequency waveforms, this is the reason you should experiment with different positions as different instruments will act inherently different, however, in general, knowing the information above, you can see that the body of the instrument acts as the lever that drives the wave, and the farther you are away from the pivot point or fulcrum, the "bridge", the higher the wave pressure levels (SPL) are.

[sabianq]

as for reducing feedback, well there are as many different techniques as there are people.
but the best way to keep feedback from happening is "microphone proximity" sounds like what it is, the closer the microphone to the sound source, the less gain the microphone needs to have to achieve unity.

and the further away from the reinforcement driver the microphone is, the more "gain before feedback" you have.

using a low pass filter set to cut or attenuate anything above 500 hz can give you up to "IMO" 15 decibels of gain before feedback as low frequencies are less inclined than the higher frequencies to feedback. (i would love to graph it sometime)

also placing the bass player against the wall or in a corner works well to.


the microphone is critical to recording instruments like the string ones. you are correct that you should use a condenser but a condenser with high sensitivity to the low ends is gold.

this is why i love the AKG C 353

[sabianq]

here is a sample of thunder taken using the AKG C535 EB condenser and a ribbon RCA microphone in two separate channels hard paned left and right respectively.

__________________________________________________ __________________________________________________ _______
WARNING: WARNING: WARNING: WARNING: WARNING: WARNING: WARNING: WARNING: WARNING: WARNING: WARNING: WARNING:
This file contains a sample of Extremely Low Frequencies (ELF) (20 Hz and below) and could damage your loud speaker if played to loudly.
Start out at 0 volume and turn it up until you see your speaker cone moving
__________________________________________________ __________________________________________________ ________________________

you will notice that the left loud speaker is moving way more than the right one. the left channel held the AKG and the right channel Held the Ribbon.

this sample is not clipped, it just carries extremely low frequency's.
ironically, when i made this recording, i was trying to sample the birds and i did not know that the distant thunder would be recorded as it was not that loud...

this is just to show you the difference between two different microphones.
the Shure SM series dynamic microphones cannot capture this.




please be careful, i take no responsibility for damaged speakers.

http://www.puredesigngroup.com/brian/samples/thunder_WARNING_ELF.wav

10 megabyte file

[GZsound]

That's actually pretty interesting. I have not had good luck micing an acoustic bass with a small condenser mic.

I agree with the low pass filter idea, but like I said, I haven't had good luck, either live or in the studio with a small condenser mic on acoustic bass.

I get best results with my AKG D112 bass drum mic if I need to get feedback rejection and if I am in the studio I find an AT 4047 works well as does my CAD M179 set to wide cardioid.. I also get good results in the studio with my RE-20.

But...in a live situation, I fall back on my trusty SM58.

I'm running sound at a three day bluegrass festival the weekend after next and I'll get another opportunity to mic or DI fifteen or so different acoustic basses.

I'm going to try my new CAD Trion 7000 ribbon on acoustic bass in the studio and see how it sounds..should be interesting.

I may even try a small condenser at the BG festival just to see...