Double Bass DIY piezo installation tweaks...

[moles]

Okay, so I've cobbled together a pickup system for myself that was *supposed* to be temporary while I saved up for a real DB pickup and pre-. Unfortunately my car barfed up its exhaust system last weekend, so the money's going to auto repairs...(ugh) and it looks like I might have to rely on what I have for awhile.
It's pretty simple really, a couple of cheap "tuning" pickups wired in parallel, crammed into my bridge wings. I have a third that I'm also trying to mount as a clicky under the fingerboard. Having some issues with the sound that I figure some tweaking of how I have them installed might help. I need some suggestions though.
The overall sound isn't bad for what I spent. If I play hard though, there is a Very pronounced "Thock!" that comes through, quite a bit louder than the note. Its a full size czech ply - acoustically that bass still has this element in the sound, but it comes across more as punchiness - when its amplified though its completely over the top. Would playing around with how tightly I have the bridge pickups shoved into the wings make a difference? Does it need to be tighter, or less so? This issue is completely due to the output from the bridge pickups, btw.
Also - I'm having a bit of a time trying to figure out how to get the clicky to stay stuck to the fingerboard. I've basically tried just taping it to the underside, but slapping the fingerboard pretty much works it loose after a couple of songs.....what does something like the K&K Rockabilly pu use to mount it?
Any suggestions will be helpful. Thanks in advance
Miles

 

[Jeff Bonny]

Auto body trim tape. It's black and ULTRA grippy...made to hold chrome body trim on cars. I installed a custom magnetic pickup hung off the fingerboard with the stuff and it did a rock solid job. Removing it was a supreme bitch though, it took half an hour of careful steady pressure....I was so afraid I was gonna break something on the bass if I pried too hard. Used judiciously the stuff is awesome.

Only wingslot pickup I have experience with is the Underwood and I like it best when they're in just barely tight enough to stay put. To my ears too tight a fit squashes the sound and kills some output. A looser fit makes for a more natural "breathy" sound.

 

[Bass]

...Also - I'm having a bit of a time trying to figure out how to get the clicky to stay stuck to the fingerboard. I've basically tried just taping it to the underside, but slapping the fingerboard pretty much works it loose after a couple of songs....

Good question.

I used "Gorrilla Tape" which is like duck tape only stronger. But now that you mention it, I think the clicky is working loose and I'm losing clicky volume.

 

[bolo]

Regarding that "Thock!" sound, experimenting with the fit of the pickups in the wing slots can sometimes make a huge difference in tone. This includes the position of the p/u in the slot and how snug or loose it is like jbonny outlined.

Sometimes too if I am careless w/ my right hand technique, I get a noticeable "thock" if plucking finger comes to rest too violently on the string below the one I just plucked. Just something else to listen for maybe.

 

[moles]

Well, thats just the thing - when I play like you just described, and its acoustic - dang, it sounds good. Nice and punchy, nice little subdued click at the start of the note...
I wound up loosening the fit a tad in the wing slots of my bridge. It helped somewhat, though there was a noticeable drop in volume. Still trying to decide if I want to live with it as is, or what. I'm putting low tension weedwackers on this weekend, so I'll wind up tweaking the pu fit more after that anyway.

 

[seamonkey]

I just use one pickup under the bridge wing.
Link Removed
I cut a pieces of a wooden wedge and shimmed it in place.

I had some weed-wackers on and it worked fine. Nice and even.

I didn't put a pickup under the treble side wing because as far as I could tell from other forums, it never sound goods. I can bet is has to due with phase cancellation across the bridge. In any case, just one pickup works great.

 

[Jeff Bonny]

I didn't put a pickup under the treble side wing because as far as I could tell from other forums, it never sound goods. I can bet is has to due with phase cancellation across the bridge. In any case, just one pickup works great.

As far as a lot of people who've used Underwoods with both sides installed a pickup on both wingslots sounds just fine...it's all in the fit. The Steve Azola trick of gluing on velvet to get the firm, secure but still loose fit instead of using wood shims works very well.

 

[moles]

Okay, update:
Did two things a couple of days ago. One was to make sure that both sides of the little p/u rubber assembly that the piezo is encased in were flat and smooth. There was a little round nub in the centre of each one (not sure why) that I exacto knifed off. Then I flipped the contact side around so that they were placed against the bottom leg of the bridge in the wing slot, rather than the wing itself. Also adjusted to a tighter fit (again) Used wine cork. The real stuff - not the newer synthetic types. The material seems to have a nice effect on things - maybe the combination of being compressable enough to enable a tight fit, and also non-resonating - same effect as the velvet I suppose. Whichever, it somehow sounds better than it did last time I had things fitted that tightly. Feedback is also nearly completely non-existant at this point. 20 bucks never sounded so good

 

[bopeuph]

Unfortunately my car barfed up its exhaust system last weekend, so the money's going to auto repairs...(ugh) and it looks like I might have to rely on what I have for awhile.

You know, you can run a car without a lot of exhaust stuff. My muffler and tailpipe aren't even there on my truck any more. Besides, it gives you better gas mileage and a few more horses.

Nick

 

[moles]

Ha! Well, guess what - it IS running with no muffler. I burned out my starter last week, so my exhaust money went to that. Frickin thing...Ah well, it got me to the gig this weekend anyway. I loves my car.