Yet another problems with feedback thread

[TVD]

I've read several of the other threads here of how to combat feedback, so I thought I'd chime in, since I'm having problems with it now myself when playing at loud volumes. This seems like a place for great advice.
So here's some info on my situation to help the advice train begin...lol I'm yet another guy who is new to Upright bass, just started this year, been playing electric bass 28 years. I play traditional country, bluegrass, and some rockabilly. I have a late 60's German made plywood Knilling. I have Barefoot Larry's weed wackers on it. My pickup is a RSII. I have two amps. My main gigging amp is a GK 400RBIV head with a SWR Goliath 4x10 cab. My other amp stays at a weekly house gig I do on a jamboree show. It's a SWR basic 350 head, with a Peavey 1810 cab. On both rigs, I play the upright and electric bass thru a D-Tar Solstice preamp/mixer. I bypass the preamp of the GK, and just use the power amp of it. Perhaps this is interesting, I have had almost no feedback issues with the jamboree show rig. Some might think the old 1810 cab is bad for upright, but it's been fine for me. Unless I accidentally turn my bass to face that rig, I've had no feedback out of it. Now that's not a real loud band, but it is a full band, keys, fiddle, steel, guitar, drums the whole thing.
I've also had no feedback problems out of the GK/SWR cab rig at gigs of moderate volume, I have one gig though that is pretty loud volume, and that's where I'm having feedback issues. I have found turning the cab away from me does help somewhat, but I've also been in a few situations with the loud honky tonk band where the stage is too small or whatever for me to turn away from it. Or I stood off to the side, and that helped some, but that's hard too cuz I sing harmony with that group, and a bit of lead vocals too. It doesn't feed back during the actual songs, unless it was a slow ballad where the notes ring, it's between songs when it feeds back. I've taken to turning the amp, or the upright channel on the D-Tar Solstice down until just before the next song kicks off, or just playing more electric bass on that gig. People dig the upright though, especially on the Johnny Cash type stuff. And I'm actually really liking the tone I'm getting, even at a loud volume, just if I could get rid of the annoying feedback.
I have tried to EQ it out using the Solstice, and it's worked to a degree, but not totally, and if I cut out all the bass and mids, it sounds like crap, plus I've read here trying to get rid of the feedback with EQ is not the answer. I love the sound of the Solstice when it's set close to flat, maybe just cutting the mids and lows a bit.
I have the loud gig again this Friday. One thing I'm going to try is the after-length dampener that came with the RSII. I haven't tried that yet. It may help a bit I think, but might not be the whole answer, if it is, great. After reading thru the posts here I'm thinking of buying a nerf ball and putting it under the tail piece, and maybe part of it under the fingerboard too. Maybe getting some foam to put in the F-holes. I don't want to tape them or anything like that, as most of my gigs are not this loud. To give you my idea of loud, I uusally have the volume on my amp set around a quarter of the way up, for the loud gig, it's about half way up, or just past half. I was wondering too if turning my RSII over might help? I don't think a loose fit there is my problem, it's in there fairly snug, and I really like the tone out of it as it's in there now, and I'd hate to lose it. I was wondering too if the fact I'm playing low tension weed wacker strings could cause more feedback then higher tension steel strings. Not sure about getting my cab off the ground, I could maybe put it on a chair or something, but even that isn't that practical for me, and still might not be high enough to really help. Turning it directly away from me has helped a lot though the times I was able to do that. I'm open to any other suggestions. Thanks.

[bolo]

TVD, seems to me like you are already thinking about all the right things.

Like you said, where you and your bass are positioned relative to the speaker(s) is key. But sometimes you can't move around much, I know.

For starters, definitely try the afterlength damper like you said. It's easy. I use a Vibramute (funny name).

I like putting my amp on a chair in some rooms, not so much to combat feedback, but because I think I can hear myself better, hone in on intonation better, and project up & out say over the drum kit (depending on how we're all set up).

I have never tried the Nerf football behind the tailpiece. Seems like it would affect the tone of the instrument too much, and I do mostly straightahead jazz nowadays. But if I were still doing loud jump blues stuff on a regular basis, I would definitely try it.

I have fit several Rev Solos on my bass. One time a bad fit did seem to contribute to feedback. I think it was too loose. I am like you ... If you get the Solo fit to where you like the sound, you really hate to mess with it. But what I did was trace the outline of the bridge wing's "foot" on the p/u with a sharp pencil. That way I can always put the pickup back in place if it ever moves. Flipping the RS over is something you should try IMO, just 'cuz in some cases you will get a real different tone. Maybe you will dig it, maybe not.

Did you try the phase reversal button on the Solstice? You'll probably hear a difference in tone, but ... listening to feedback is probably much more painful. If I understand it right, its effect will also vary based on your distance from the amp.

[mstclairmiller]

My bass will feedback if the bridge has shifted slightly. If it is perfectly fitted I have no problems generally. Have a good luthier check it out. Getting the cab away from a wall and or corner helps.

I hate having to use the notch filter on my amp, and generally only have to when it is the setup of the stage that is the problem, eg with a big beam across the ceiling just in front of the stage setting up a resonant frequency.

[moles]

You know, I've been going through almost exactly the same scenario over the past week or so. I'm prepping a setlist for a new country/-billy band I'm putting together. Couldn't hack slapping on the spiros (or whatever I had on there...) so I'd gone with real light guage weedwackers. This is all happening in my rehearsal room mind you, but the feedback at what I figure will be stage volume was reee-dickulous I tried letting it feedback while I moved my hand around the bass to try to figure out what was resonating first, and it wound up being the top plate. I tried all kinds of things - moving the bass around, adjusting the fit of my bridge piezo, etc. (Taking a look at the bridge feet to make sure they're in position would have been a good one, but I hadn't thought of that.)
Long story short - the bigger guage weedwacker stock that I'd ordered finally came in, and when I put them on - problem solved. The only other thing different about my setup, is one tiny piece of foam under the tailpiece, that's holding the 1/4 inch jacks for my pickups. I wouldn't say its dampening effect is large though - and nowhere near what a nerf ball would do!
I was posting about this on rockabillybass.com also, and also mentioned on there that I was considering making a short 1/4" phase reverse cable. I don't have a pre- with a phase reverse setting, but then I don't really need to stick a preamp in front of my Ashdown since it has a high impedance input. Might be an easy 5$ solution for those of us that don't have a phase switch.