| Originally posted by Henko |
By the way, do piezos feedback easily?
No, they don't feedback easily
but they do feed back. If you put the bass too close to it's speaker(s) you'll get feedback, especially of the amp is turned up high.
It also depends some on your amp rig. Four 10" speakers, or eight of them will give you more volume before feedback, and sound better for an upright, than two fifteens, or eighteens, for instance.
In general, most piezo pickups arel not a problem, except in extreme high-volume or high-carelesness situations.
Different types of piezos will be different in this respect, largely based on how they mount.
Wing-mounted pickups, like the BassMax, Underwood, & Shadow are not too bad. Anything that mounts directly against the body will be a lot worse.
Piezos that are stuck onto the bridge with adhesive will be about the same as wing-mounts, perhaps slightly worse.
Any microphone or microphonic pickup will reproduce the true sound of the bass the best, and feed back the worst.
The back & top of the bass are designed to take string vibrations from the bridge, and amplify them by vibrating, transmitting those vibrations to the air.
This also works in reverse. The large surfaces of the back & top will collect sound vibrations from the air and transmit them up the bridge instead.
There are mechanical things you can do to help control feedback with a piezo, like cramming nerf-footballs between tailpiece, or fingerboard, and the top etc.
You can build bolt-together (inside-outside) wooden plates that close off the F-Holes and damp the vibrations of the top somewhat. They have to be gasketed with some kind of padding, to prevent noises, and to keep from goofing your finish.
You can eliminate feedback with a magnetic pickup, like the Moses Lace (available at www.urbbob.com
), but that's about the only way to get it as resistant as an electric guitar. But then you have to worry about whether the strings you like to use have enough metal-content to work with a magnetic pickup. They are pretty much a steel-string-only proposition. A lot of mag pickups tend to make you bass sound more like a bass guitar, also.
BTW, how much is this Shadow going to cost you?? Bob sells the BassMax for $87. It's a lot of bang for the buck.