Additional mic in a semi-hollow guitar without drilling an extra hole

[Lukasz]

Hi,

I would like to install a small condenser mic in my semi-hollow body guitar, which currently has one magnetic pickup, two potentiometers (volume and tone), and a mono output jack.


Is it technically possible to connect the mic to the existing circuit and replace the output with a TRS jack, so that when a mono cable is plugged in only the magnetic pickup works,
and when a stereo (Y) cable is used the output can be split into two separate signals, allowing the microphone to be connected to a preamp ?

[Peter C]

I'm sure it's feasible to run two TS (mono) jacks from a TRS output using a splitter cable. However, you may want to carry out some trials with a mic inserted in an f-hole to see whether feedback is going to be an issue, especially at stage volumes.

[Rodney Gene]

Hi,

I would like to install a small condenser mic in my semi-hollow body guitar, which currently has one magnetic pickup, two potentiometers (volume and tone), and a mono output jack.


Is it technically possible to connect the mic to the existing circuit and replace the output with a TRS jack, so that when a mono cable is plugged in only the magnetic pickup works,
and when a stereo (Y) cable is used the output can be split into two separate signals, allowing the microphone to be connected to a preamp ?

To the existing circuit? No, they would be sharing the same hot/negative. The internal mic needs power. The TRS jack uses the ring to complete the circuit for the battery when using a mono cable.

[Lukasz]

To the existing circuit? No, they would be sharing the same hot/negative. The internal mic needs power. The TRS jack uses the ring to complete the circuit for the battery when using a mono cable.

And what if mic were powered by an external preamp ?

[Rodney Gene]

And what if mic were powered by an external preamp ?

As in external phantom power? No, TRS cables do not supply voltage as far as I know. That requires XLR.

[pcjazz]

CIrcuitry aside, the sound from an internal mic is likely to be unpleasantly boomy/boxy. Try a piezo under the bridge instead.

[Bob_Ross]

the sound from an internal mic is likely to be unpleasantly boomy/boxy.

^^^This.

I've done experiments with a small lavalier omnidirectional condenser microphone in/on my archtop, and any mic location inside the guitar just sounds weird. I won't say it sounds awful...but pretty close.

Best mic location I've found is clipped to the pickguard so it's picking up the strings mostly, while picking up a bit of sound from the top, but is pretty far away from the f-holes.

[Rodney Gene]

^^^This.

I've done experiments with a small lavalier omnidirectional condenser microphone in/on my archtop, and any mic location inside the guitar just sounds weird. I won't say it sounds awful...but pretty close.

Best mic location I've found is clipped to the pickguard so it's picking up the strings mostly, while picking up a bit of sound from the top, but is pretty far away from the f-holes.

Although Metheny has always used F-hole mics with clips.. he just blends a tad in. His archtops are modified with XLR inputs as a 2nd input. I think the 'boomy/boxy' comment was in regards to semis, not full archtops.

[SOLR]

Hi,

I would like to install a small condenser mic in my semi-hollow body guitar, which currently has one magnetic pickup, two potentiometers (volume and tone), and a mono output jack.


Is it technically possible to connect the mic to the existing circuit and replace the output with a TRS jack, so that when a mono cable is plugged in only the magnetic pickup works,
and when a stereo (Y) cable is used the output can be split into two separate signals, allowing the microphone to be connected to a preamp ?

One way to do this is like Gilad Hekselman 's "Victor Baker" :

Both systems are separate. While possible it is not recommended to send phantom power through trs.

S

[Peter C]

I don't have any personal experience of using a "shared" TRS output as I attached a separate, powered lavalier mic into a DI box. The "boxiness" alluded to here was an issue in my particular experiments, but it's likely going to depend on the acoustic qualities of each instrument; Gilad's Victor Baker sounds pretty good to me.

[Lukasz]

I did a small test to see if this would work at all. I placed a cheap Boya microphone in the lower f-hole and mixed it slightly into the pickup signal, with a small EQ adjustment.
I’m attaching a short sample. I start playing with the microphone on, then I turn it off and on again...

[Peter C]

@Lukasz, in your clip the little bit of mic definitely adds a more open quality to your sound and in controlled recording conditions, it could work well. As I mentioned, live it could howl. Try it through an amp at gig volume.

FWIW, I wasn't paying attention but it seems Gilad's tone is coming from the mag pickups only in that clip and the f-hole output is for a piezo bridge (with a run-down battery), not a mic.

[Woody Sound]

I did a small test to see if this would work at all. I placed a cheap Boya microphone in the lower f-hole and mixed it slightly into the pickup signal, with a small EQ adjustment.
I’m attaching a short sample. I start playing with the microphone on, then I turn it off and on again...

FOA, I think the whole thing sounds fantastic. What are the two time markers for turning the mic off, then back on?

[Woody Sound]

How wide is the guitar's rim?