Piezo for a hollowbody

[Bernardduur]

As I really like the sound of my new EKO acoustically I wanted to try to add a Piezo element to it to capture that "sound". My current experience with piezo elements are:
- In bridges; not an option as my bass has a roller bridge
- as small elements placed somewhere

The latter one I tried several times on other basses...... with an OK result. OK, the sound is very very faint and tinny but with a good preamp (piezo high impedance preamp) the sound is bearable. I think I'll go with this latter option. Then the question comes to mind: are there any differences between models? For example, I can buy cheaply those Piezo trigger around the corner. Is there a big difference between these triggers when compared to for example Barcus and Berry models (I know em from their piezo preamps which are quite easy to build ).

[Basvarken]

Why tinker with a piezo when the result is only "bearable"?

Couldn't you try a little microphone inside the hollow body?
I've seen that on an acoustic guitar (Gibson Super Jumbo) of someone I know. It works like a charm.

[Bernardduur]

Couple of things

- With a mic I have to go for a condenser mic, not a dynamic mic (I really dislike the sound of a dynamic mic inside a body). Condenser mics need power, so I need to build in a circuit + power.......... and if I wanna do that elsewhere I need to add a different output.
- Mic is bit more open to feedback and such; don't want too much feedback.
- Piezo is easily installed and (with a stereo jack) easily fed outside the body for the preamp

Dunno; maybe I never use it Just curious if there is something more. Double bass users use em all the time

[Chris P.]

It's a dutch party over here:)

There's a Gibson or Epiphone Les Paul out with a pick up (which i believe is piezo) at the end of the fretboard. It isn't a bass but you could check that one out tosee how it works and how it sounds.

[Basvarken]

Yeah I saw that the other day. The Epiphone Les Paul Ultra II. It's pretty amazing.

http://nl.youtube.com/watch?v=Ao2CVfUwNjI&feature=related

[Bernardduur]

Yeah, I checked the Nano mag...... still, this takes the sound from the strings, not the body (directly )


Right now I am experimenting with Electret mic(s) I scavanged from an old tuner

[Pilgrim]

Couple of things

- With a mic I have to go for a condenser mic, not a dynamic mic (I really dislike the sound of a dynamic mic inside a body). Condenser mics need power, so I need to build in a circuit + power.......... and if I wanna do that elsewhere I need to add a different output.
- Mic is bit more open to feedback and such; don't want too much feedback.
- Piezo is easily installed and (with a stereo jack) easily fed outside the body for the preamp

Dunno; maybe I never use it Just curious if there is something more. Double bass users use em all the time

You could use a mike that requires phantom power if you have an intermediate box that provides it - I believe the ART Tube MP will provide phantom power via an XLR cable.  Finding the right mic to go inside the body is another matter, and making sure it has a small enough cable to go inside the body.

OTOH, I've used electrets for many audio applications as a radio and TV producer, and I have no problem with them. Just put in a fresh battery and have fun.

I think I'd be tempted to try a piezo that could be fastened inside the body with adhesive, and remove a pickup long enough to get access to the body interior and mount the piezo, then re-install the regular pickup.  Not sure how I'd get the mic lead out of the body...I'd probably bring it out an F-hole during experimentation, and when i was satisfied with the sound, add another jack on the body OR (here's an off-the-top-of-the-head thought) see if I could replace the mono jack with a stereo one and use the second connector on the stereo jack for the second pickup. Seems like that would require both pickups to have a common ground, though.

[Bernardduur]

You could use a mike that requires phantom power if you have an intermediate box that provides it - I believe the ART Tube MP will provide phantom power via an XLR cable.  Finding the right mic to go inside the body is another matter, and making sure it has a small enough cable to go inside the body.

OTOH, I've used electrets for many audio applications as a radio and TV producer, and I have no problem with them. Just put in a fresh battery and have fun.

I think I'd be tempted to try a piezo that could be fastened inside the body with adhesive, and remove a pickup long enough to get access to the body interior and mount the piezo, then re-install the regular pickup.  Not sure how I'd get the mic lead out of the body...I'd probably bring it out an F-hole during experimentation, and when i was satisfied with the sound, add another jack on the body OR (here's an off-the-top-of-the-head thought) see if I could replace the mono jack with a stereo one and use the second connector on the stereo jack for the second pickup. Seems like that would require both pickups to have a common ground, though.

Thanks!

That is exact what I am doing right now. I tried several piezo's + Barcus and Berry 3000 preamp but was not satisfied (yet???) with the result. Now I have 3 new electrec mics (these things are so cheap!) I am experimenting with:
- One goes from 100 Hz to 1500 Hz (from the tuner)
- One goes from 60 Hz to 15.000 Hz
- One goes from 20 Hz to 22.000 Hz
Good results with the last one. Oh, and I use a clone of the ART for my mic uses; the Behringer MIC200

[Chris P.]

Basvarken must have told you about the Behringer? I believe he's a big Behringer fan!

[Bernardduur]

Basvarken must have told you about the Behringer? I believe he's a big Behringer fan!

No....... I have this unit even longer then I know Basvarken
Nice addition to the Behringer: 2 LED's must give you the impression the tube is lighting up (as the stock Behringer tubes have encapsulated heaters)

Right now the mics sound too thin and trebly; maybe I should try to mount em somewhere else inside the body.

[Basvarken]

Basvarken must have told you about the Behringer? I believe he's a big Behringer fan!

Haha, not exactly. 
But I must admit I have a Behringer MIC100 at home. Mainly because Floor uses a Beta 87 that needs phantom power. Not all sound consoles have that option. So it's nice to have it handy just in case.

The tube sound of the MIC100 sucks IMHO...Another proof that just one single 12AX7 doesn't make a classic Tube sound 

[Bernardduur]

The tube sound of the MIC200 sucks also...... but cleared up greatly when I added a better tube to it.


As for the piezo / mic...... I think I overlooked one small detail. Maybe the body does not resonate in the same frequency as the bass sound you hear amplified. With the mic all I get is a really nice pure sound but no bass........ more like a cross of a guitar / bass..........

I LOVE experimenting

[Pilgrim]

One thing to remember - if you use a lavaliere electret mike, they are almost all designed with EQ to produce accurate sound when mounted on a lapel underneath someone's chin. In other words, they are not designed to reproduce sound accurately when you speak directly into them.  (I've been a radio and TV producer and HATE to see someone holding a lav mike in front of their mouth.)

You might have to find a lavaliere mike designed with unusual frequency response curve to get accurate reproduction inside a bass.

[rahock]

As for the piezo / mic...... I think I overlooked one small detail. Maybe the body does not resonate in the same frequency as the bass sound you hear amplified. With the mic all I get is a really nice pure sound but no bass........ more like a cross of a guitar / bass..........

I was kind of suspecting this might be how things turned out. The thickness of the wood and internal construction are probably far from optimal for good resonace and piezo use. Even a lot of ABGs ,that are suposedly designed to be played unplugged, lack  the resonance to produce a decent bass sound unplugged. A great deal can be added with a good preamp and EQ but when controls are set pretty flat they don't sound very much like a bass.
If you keep experimenting, I bet you can get what you're looking for by adding the juice via preamp/EQ. I'm very interested in what you come up with and hearing your opinion on whether or not the piezo path was worth the effort. I am also thinking the single coil 51 P style pickup idea would be a great experiment Lots of bottom and lots less BS. ln any event, my hat's off to you for doing something that I've been curious about for years

Rick

[Pilgrim]

The more I think about it, the more I'd try taping a lav to the underside of the body under the bridge...but I'd leave the air holes in the mic uncovered. Contact with the body would be helpful, but there's also a boundary air effect: sound moves along a flat surface.  I'd want to be able to pick up the sound moving parallel to the surface inside the instrument.

This same boundary sound effect is used for pressure-zone-mics (PZM) mikes, which are mounted on a flat piece of material to capture sound waves in a room and move them along the surface to the center of that surface where the mic is mounted.

(Old Radio/TV producer audio trick....lay/tape an omnidirectional mic in the middle of a table or on a floor to serve as a PZM mic for the whole room.)