Double Bass Ischell C3..... Adding THE 'AIR'..... to a contact mic

[rickwolff]

Maybe this should have been obvious - I've been toying with this idea for some time and decided to put it to the test.

One complaint I've had with contact mics is that they lack 'THE AIR' you hear with an open-air mic. They sound a bit 'muffled'.

Well, maybe more than one way to skin this cat (sorry PETA, I'm actually a Huge Animal Lover).

When the microphone is in the Open Air you get that 'airy sound'. With either a contact mic or a piezo going 'straight to the board' you lose that air.

However, You DO Hear that AIR when you put the recorder in front of the speaker of your amp - even when using a contact microphone. After all, there is Open Air between the speaker and the microphone.

Don't believe me? Just listen to the sample recordings below. The first is 'direct to board' with no air. The second one with the mic about a foot in front of the bass amp. Notice the difference.

Also notice, if you will, that you can clearly hear my talking when the mic is in front of the amp, but there is virtually No Bleed when going directly to the board. So to some extent, you have to make a choice - which is more important - almost total isolation with No Bleed or a more open 'airy' sound.

A little trick - you can run through a speaker which itself is isolated - even if the bass if right in the middle of the other instruments. The signal you send to the amp is 'Bleed Free' but the sound coming from the speaker to the amp is adding air.

Check it out.

BTW, I notice that with the mic in front of the amp the sound has a lot more high frequency. I had the mic only about 10 inches in front of THE MIDDLE of the amp so it was right in front of the line-array of tweeters. It would probably sound better and more natural if it were off the the side a bit.

 

[drwv]

No offense meant, but I don't believe you!

I think your recorder is recording the acoustic sound of your bass, with the same amount of gain that it's recording your spoken voice.

Put the amp cabinet in an isolation room and record it there!

The "airy" sound of backing a microphone away from the bass is due to the fact that it's picking up vibrations from all over the body of the bass, and even reverberations from the room, where a close mic or contact mic is picking up vibrations from only a single point on the bass.

 

[rickwolff]

No offense taken. I often don't believe myself either.

I will try putting the amp outside of the room and micing it there to see if that makes a difference.

And yet....even close micing with an open-air mic gives a more open and realistic sound than a contact mic, though admittedly that comes at the cost of 'bleed'.

I wonder if we're way too concerned about bleed. Does it really matter? Consider this recording by the Christian McBride trio and check out where his mic is. You can't tell me that doesn't pick up a lot of drums and cymbals.

And is that a
Electro-Voice RE20 Dynamic ??

 

[drwv]

Looks like he's got a bridge-mounted pickup on his bass. I only see a 1/4" input into that GK head behind him, so the pickup is probably going to the amp, and the mic and a DI signal might be blended in the mix.

I don't hear any crazy phasing artifacts from bleed, but I also bet that NPR has a better FOH crew than most of the dingy places I play!

 

[sean_on_bass]

Maybe this should have been obvious - I've been toying with this idea for some time and decided to put it to the test.

One complaint I've had with contact mics is that they lack 'THE AIR' you hear with an open-air mic. They sound a bit 'muffled'.

Well, maybe more than one way to skin this cat (sorry PETA, I'm actually a Huge Animal Lover).

When the microphone is in the Open Air you get that 'airy sound'. With either a contact mic or a piezo going 'straight to the board' you lose that air.

However, You DO Hear that AIR when you put the recorder in front of the speaker of your amp - even when using a contact microphone. After all, there is Open Air between the speaker and the microphone.

Don't believe me? Just listen to the sample recordings below. The first is 'direct to board' with no air. The second one with the mic about a foot in front of the bass amp. Notice the difference.

Also notice, if you will, that you can clearly hear my talking when the mic is in front of the amp, but there is virtually No Bleed when going directly to the board. So to some extent, you have to make a choice - which is more important - almost total isolation with No Bleed or a more open 'airy' sound.

A little trick - you can run through a speaker which itself is isolated - even if the bass if right in the middle of the other instruments. The signal you send to the amp is 'Bleed Free' but the sound coming from the speaker to the amp is adding air.

Check it out.

BTW, I notice that with the mic in front of the amp the sound has a lot more high frequency. I had the mic only about 10 inches in front of THE MIDDLE of the amp so it was right in front of the line-array of tweeters. It would probably sound better and more natural if it were off the the side a bit.

How would this translate to a live situation? Most don't record using a contact mic and use primarily for live application.

 

[crd]

Bleed through your amp not so great. Some bleed in a nice room to tape = a classic sound. I wish I had some of you all energy and enthusiasm for amplification... I've had the Ischell sitting in it's shipping packaging for a month now because I hate fussing with this stuff.

 

[drwv]

Agree with crd, some bleed in a recording might sound good. The bleed that you pick up from your close mic is the "room sound" of the other instruments, and vice versa. So long as it's not creating destructive interference, it's a sort of multipath reverb.

But for live sound, if everybody is on the edge of feedback, then the bleed that your mic amplifies just might push them over the edge into feeding back, or that almost-feedback ringing sound, or comb filter phasing artifacts. Not to mention that the instrument(s) bleeding into your mic might have compression or gate or heavy EQ on their channel, and now FOH might have to deal with the same issue on your channel, whether you want it or not.

Disclaimer: I Am Not A Live Sound Professional, I've just had a handfull of frustrating gigs in an acoustic trio where everybody is mic'ed (and/or everybody but me).

 

[rickwolff]

The Very Best sound I get is unamplified, standing with my back to the corner of my music room with the walls acting as a reflector and 'amplifier' of the acoustic sound.

Is it too much to ask for THAT SOUND but about four times louder ON THE GIG.

Yeah, maybe it is (but I'm sure I'll keep trying).

 

[statsc]

The Very Best sound I get is unamplified, standing with my back to the corner of my music room with the walls acting as a reflector and 'amplifier' of the acoustic sound.

Is it too much to ask for THAT SOUND but about four times louder ON THE GIG.

Yeah, maybe it is (but I'm sure I'll keep trying).

I knew a guitar player (sadly passed on now) who loved the sound of his guitar sitting on his couch, and always complained about not being able to bring his couch to gigs!

 

[Earl]

The Very Best sound I get is unamplified, standing with my back to the corner of my music room with the walls acting as a reflector and 'amplifier' of the acoustic sound.

Is it too much to ask for THAT SOUND but about four times louder ON THE GIG.

Yeah, maybe it is (but I'm sure I'll keep trying).

I try to find a corner wherever I play (not always possible of course) but this gives me the best sound with only minimal amplification needed, if at all.