Internal Mic placement: the sound hole makes NO sense to me?

Joost Assink · #1 08-30-2016, 04:15 AM

Ok, as you might've read, I'll be buying and installing a DPA4061 with a K&K mini in my latest build. Now I am installing it before the back is on the guitar so I'll have maximum access. However, I won't be able to test mic placement because the strings won't be on for another month while finishing the guitar.

Now I always see internal mics pointing out of the sound hole, which makes no sense to me because that's basically a bass reflex port (Helmholtz resonator), and if I'm miking a guitar in the studio, I need to stay away from the sound hole, even with the side of a Cardioid pickup pattern.

A friend of mine who uses an internal mic says he has fine results placing it on the end of the female jack plug inside the guitar and he also says a good omni mic inside the guitar isn't too sensitive to placement as long as you stay away from the sound hole. I remember reading that Laurence Juber also had a guitar tech put his mic in the back of the body and him liking the results.

So, those with experience, can I place it inside the box near the end plug or do I really need to get close to the sound hole?

Mooh · #2 08-30-2016, 05:01 AM

Many years ago when I used Miniflex internal mics, I found that doubling back the goose neck so that the mic was closer to the X brace was better sounding than at the soundhole. Every guitar was different but the soundhole wasn't optimal on any.

M19 · #3 08-30-2016, 05:29 AM

Pointing at strings per K&K instructions. Installed in a Martin 00 and a McIlroy pointing at the b-string. Works fantastic.

ljguitar · #4 08-30-2016, 07:54 AM

Quote:

Originally Posted by Joost Assink

Ok, as you might've read, I'll be buying and installing a DPA4061 with a K&K mini in my latest build. Now I am installing it before the back is on the guitar so I'll have maximum access. However, I won't be able to test mic placement because the strings won't be on for another month while finishing the guitar.

Now I always see internal mics pointing out of the sound hole, which makes no sense to me because that's basically a bass reflex port (Helmholtz resonator), and if I'm miking a guitar in the studio, I need to stay away from the sound hole, even with the side of a Cardioid pickup pattern.

A friend of mine who uses an internal mic says he has fine results placing it on the end of the female jack plug inside the guitar and he also says a good omni mic inside the guitar isn't too sensitive to placement as long as you stay away from the sound hole. I remember reading that Laurence Juber also had a guitar tech put his mic in the back of the body and him liking the results.

So, those with experience, can I place it inside the box near the end plug or do I really need to get close to the sound hole?

Hi Joost
I have K&K dual source rigs in 4 guitars. I'd been playing dual source rigs for nearly 7 years before installing a K&K and the mic placement seemed like it just had to be 'wrong'.

So when I had the first installed I experimented with many placements, and eventually, just because it was an experiment, I put it where they recommend, and the sound came into focus and it worked great.

Even though I experimented on guitar number two it was installed in, I eventually put it where they recommend...and you guessed it, works great. It has worked great for all four guitars.

I'm resolved to the thought that it doesn't matter what it looks like when it sounds this good! I do use an anti-feedback big black soundhole plug at one venue, and when I use it I need to reverse phase on the mic and the sound is as though there was nothing in front of the mic.

I still don't know why it works this way so well. And it works equally fine with my guitar with a side port, and in a mini-jumbo, dreadnought and two OM sized instruments. I don't fret about it anymore.

Hope this adds to the discussion.

NoodleFingers · #5 08-30-2016, 02:48 PM

I'm pretty sure that most internal mics (like the one that comes with the Trinity) are cardioid, so I don't think anything about the placement of those will be especially applicable to a DPA 4061. My understanding is that the placement of those cardioid mics toward the soundhole is something that has largely been discovered through trial and error to be the most satisfactory.

But I am VERY interested to hear how your setup works out, because I am planning the exact same thing for a guitar I'm having built by Trevor Kronbauer. And I am keenly interested in where I should place the DPA 4061.

Doug Young (on this forum) has done a lot of work with different mic/pickup systems and placements. The information (and sound clips) are all on his website. He recommends a DPA 4061 placement on the underside of the soundboard, near the hole, in the direction of the end block. That is what I had thought I would do.

But PLEASE tell us where you place the mic and how it works out, because I'd love to put the mic a little more out of sight, in a more convenient spot.

Good luck!

maxtheaxe · #6 08-30-2016, 04:12 PM

I've gone through a similar process as ljguitar. This was when fitting for a dual source Fishman Pocket Blender that had a UST and a Crown Lavolier condenser through an external pre-amp.

I tried various placements of the condenser only to find that it really only worked well when pointed at the strings from inside the guitar. I guess any woofiness from proximity effect or from the bass reflex effect of the soundhole was sufficiently off-axis to that mic to not be an issue.

NoodleFingers · #7 08-30-2016, 05:07 PM

Quote:

Originally Posted by maxtheaxe

I've gone through a similar process as ljguitar. This was when fitting for a dual source Fishman Pocket Blender that had a UST and a Crown Lavolier condenser through an external pre-amp.

I tried various placements of the condenser only to find that it really only worked well when pointed at the strings from inside the guitar. I guess any woofiness from proximity effect or from the bass reflex effect of the soundhole was sufficiently off-axis to that mic to not be an issue.

Was that Crown mic a cardioid or omni-directional? They make both. And it would probably make a big difference in placement.

j3ffr0 · #8 08-31-2016, 06:42 AM

I added the optional internal condenser to my Alvarez MC90c soon after I bought it. I've been running that guitar dual source for a long time. Trough trial and error I eventually settled on a placement under the top, near the sound hole, pointing towards the neck block. That guitar has always sounded better than any of my other guitars without a dual source system plugged in.

I have recently used another internal mic placed in a similar position with my other guitars plugged into a free channel of my amp -- effectively creating a dual source system. Same placement works for me in other guitars. I usually need very little eq on the new mic, but it can depend on the guitar.

As I recall (although it's been 8 years), pointing the mic out of the sound hole wasn't terribly bassy as what we get when pointing a mic into the sound hole. I recall not liking like the additional liveliness the mic gave the right hand over other placements-- more attack than I wanted, but I play with nails and that was a nylon-stringed guitar. Never tried anything close to the end block. I did point towards one of the sides of the guitar, and I found that too bassy. I pointed towards the end block from somewhere between the sound hole and bridge and found that too bassy for my taste as well. Take this all with a grain of salt, because your mic is much better than the one I did my experimenting with.

KevWind · #9 09-03-2016, 07:52 AM

Actually when you think about it , (and likely from a pure physics of sound propagation standpoint) there is probably isn't reason to believe that you are going to get the same type of sound (and or bass buildup) from inside the sound hole pointed out and up at the strings a 1-3 inches distance,--- as from outside the sound hole with mic pointed in at a 180 degree opposite direction from an internal mic, and at say 6-18 inches from the strings.

chitz · #10 09-03-2016, 08:59 AM

Just a few days ago I installed the K&K Trinity Pro system in one of my guitars.

I placed the mic right where K&K, LJ and the gang here say it works and I concur it does seem to work well in that location facing out of the sound hole.

Hot Vibrato · #11 09-05-2016, 06:55 AM

In theory, it makes perfect sense to point the mic out of the soundhole if it's a cardioid mic. Any other mic placement would result in an unnatural bass response due to proximity effect.

NoodleFingers · #12 09-21-2016, 11:04 AM

Joost...

Have you finished the guitar yet? Where did you place the DPA 4061, and how does it sound?

Schertler · #13 09-22-2016, 03:15 AM

Hi there,

I hope my experience might be interesting for you ....
I have experimented with almost all acoustic pickup types and applications, it was not really a fun task and took about an year to build, install and test them all. And, there was experimenting with internal mic placement as well.
After all experiments with all piezo (UST, SBT ...), magnetic (sound-hole) and mic systems, I have fixed with only mic-system and removed others all, I do not find that other pickups do contribute anything to the mic sound, moreover, they even ruin it to my ear. Rubber sound-hole cover is a very effective tool for controlling feedback etc......
Placing internal mic: my results show that the best location for the internal mic is the spot of the high strings (EBG) under the top of the guitar right behind the bridge. Only there the mic sounded well-balanced and had the best crisp highs.
This is Oktava MKE-5B ECM microphone (4.5V internal battery) with internal miniature audio-transformer wired to B-Band on-board preamp.

Good luck!