Double Bass Soundspot (Bass Max?) = FEEDBACK!

[SirFunk]

Hi there,

I just had a gig tonight... first real gig with my new amp (EA iAmp 500 and Wizzy 12) ... i LOVE that amp.. it sounds awesome for electric and OK for my upright... now .. ok, there's the problem... my upright sounds... in order for me to get it to a volume that is loud enough for ME to hear (let alone anyone else in the room) it feeds back HORRIBLY any open string = instant feedback and if i don't conciously dampen strings most closed notes feedback too. I had the same problem with my old amp (it fed back, it also sounded much worse, but it fed back too)... what it seems like to me is that the soundspot is in a way TOO sensitive... like it's too sensitive but doesn't put out enough signal, so by the time i turn it up to a good volume even the slightest noises get amplified, along with my playing.. sort of like there's not enough "width" to the output.. if that makes any sense?

That being said... does this make sense to anyone? Unfortunately i live in the middle of nowhere the nearest shop that would have bass pickups in stock is probably a good 4 hour drive so i can't just try another one.

thanks for any input.
-Jeff

 

[Chris Fitzgerald]

The conventional thing to do would be to dampen the afterlength (between bridge and tailpiece) of the strings with something heavy enough to keep them from vibrating. A handtowel or bandana woven between the strings should do nicely. If you're playing at absolutely SILLY volume levels, you might try putting something between the table and the tailpiece as well, but hopefully that won't be needed. Try this stuff first.

Next, you'll want to find out which frequencies are feeding back. If it's low feedback, try cutting everything below 50 hz (DB only, of course) and make sure you don't have the "deep" switch engaged. If there's still low feedback, try cutting a bit at about 200-250 hz. If it's high feedback, try cutting between 1-2k. The parametric EQ on the iAmp is perfect for all of these adjustments.

Last, you can also try looking at the fit of the Bass Max (not too tight, but not too loose), and/or try running a preamp as an impedance buffer. Good luck!

EDIT: Ooh, almost forgot - don't put the bass right in front of the speaker. If you can, raise the speaker up on a chair, and get the bass out of the direct line of fire of the speaker cab.

 

[SirFunk]

The conventional thing to do would be to dampen the afterlength (between bridge and tailpiece) of the strings with something heavy enough to keep them from vibrating.

Yeah, i usually do that... I accidentally left my towel at home when i was packing up this time. However I think i've noticed it before even with a towel dampening the afterlength.

Next, you'll want to find out which frequencies are feeding back. If it's low feedback, try cutting everything below 50 hz (DB only, of course) and make sure you don't have the "deep" switch engaged. If there's still low feedback, try cutting a bit at about 200-250 hz.

I'm pretty sure it was low feedback, i had deep and countour I off AND i had both the low and low mid turned down to -15, still fed back.

So you think that probably any other pickup would do just as good? I've been thinking about getting a realist or a full circle. As far as a preamp goes... i thought that the EA had a preamp and that would do what i needed... no?

 

[Packinmn]

... in order for me to get it to a volume that is loud enough for ME to hear (let alone anyone else in the room) it feeds back HORRIBLY...

I play blues with bands that tend to play at fairly high SPL and this has continually been a struggle for me. I've tried a bunch of different stuff... different cabs, preamps, afterlength muting, muting under tailpiece, etc... Last week I got a Revolution Solo pickup to replace my Bassmax and it was pure joy. I no long worry about tone and feedback issues and that has freed me up to start playing the things I was hearing in my head the whole time.

Will it feedback?... Of course. You still need to do the common sense things like raising your cabinet off the floor and keeping your bass out of the line of fire. When you turn up the master, roll back a bit of bass... you know the deal.

Of course, I've only used it for one show so far, so take my opinion for what it's worth. But, for me, this has made more of a difference than any other single change I've made in my quest for tone. Good luck!

 

[Bob Gollihur]

Hi there,

I just had a gig tonight... first real gig with my new amp (EA iAmp 500 and Wizzy 12) ... i LOVE that amp.. it sounds awesome for electric and OK for my upright... now .. ok, there's the problem... my upright sounds... in order for me to get it to a volume that is loud enough for ME to hear (let alone anyone else in the room) it feeds back HORRIBLY any open string = instant feedback and if i don't conciously dampen strings most closed notes feedback too. I had the same problem with my old amp (it fed back, it also sounded much worse, but it fed back too)... what it seems like to me is that the soundspot is in a way TOO sensitive... like it's too sensitive but doesn't put out enough signal, so by the time i turn it up to a good volume even the slightest noises get amplified, along with my playing.. sort of like there's not enough "width" to the output.. if that makes any sense?

That being said... does this make sense to anyone? Unfortunately i live in the middle of nowhere the nearest shop that would have bass pickups in stock is probably a good 4 hour drive so i can't just try another one.

thanks for any input.
-Jeff

The Soundspot is made by K&K for DTAR (Seymour Duncan), and in K&K parlance is the Hot Spot (very small) or Big Shot (larger). It is not the Bass Max and not something I'd personally recommend for URB.

It's a single transducer and not really sufficient for serious URB use. If the transducer is the larger of the two (about 3/4" round), the Double Bass pickup is the Double Big Twin, which is FOUR of those transducers in an array, under each string at the top of the bridge. The Double Big Twin (or any transducer stuck to the top of the bridge) will feedback more readily than the Bass Max, simply because its position is on a thinner piece of wood than the thicker wing position of the Bass Max.

If you are playing at higher levels or in a very noisy environment, the ambient sound will cause undamped strings to vibrate, which generates sound at the amp, and the cycle of sound just builds until you dampen the strings. That's a curse of any most any acoustic instrument.

 

[Jason Hollar]

Sir Funk -- I've had very good luck with the Full Circle not feeding back. I do remember not liking my Realist at moderate to loud volumes because it started to sound muddy.

Yes, I'm looking at the iamps for the very reason that they have piezo-friendly inputs as well as plenty of power. However, it's wise to have some tone shaping preamp box in your kit to help out. I use a trusty Boss Bass EQ ($89). It has an awesome amount of gain boost (or cut) and handy EQ frequencies that target the major feedback areas.

Of course, the iamp's EQ (Tone Shaping) section is quite impressive so spend some time off stage dialing in a workable sound. Pickups are a huge part of the equation -- might have to spend some bucks and do some more experimenting. Good luck.

 

[greitzer]

in order for me to get it to a volume that is loud enough for ME to hear (let alone anyone else in the room) it feeds back HORRIBLY any open string = instant feedback and if i don't conciously dampen strings most closed notes feedback too ... like it's too sensitive but doesn't put out enough signal, so by the time i turn it up to a good volume even the slightest noises get amplified, along with my playing.. sort of like there's not enough "width" to the output.. if that makes any sense?-Jeff

Sir Funk -- welcome to the "joys" of figuring out how to amplify a double bass without feedback. This is one seemingly endless journey, so prepare yourself for a lot of experimentation.

Based on my own experience, I can second a couple of the motions that other post-ers have made. Here are the two most important feedback fighters for me.

1) It's critical to not let your pickup "see" the amp directly. If you're positioned in front of the amp, be sure that your body, and the bass's body, are fully in between the amp and the pickup. If the pickup can "see" the amp even a bit, this adds to the feedback. So this also means don't position yourself to the side of the amp (either side), because there's a directly line of "sight" from the pickup to the amp from the side.

2) The Fishman ProEQ preamp has helped me get higher volumes before feedback sets in. I don't know if it will necessarily help you but it might. I'm using an Underwood pickup (which fits in the bridge wing slots on each side), a typical piezo pickup, and the preamp helps me wring a bit more volume out. I plug the preamp into the effects return of my amp, rather than into the regular input jack. (this also improves tone, since it bypasses the amp's built-in preamp and I can rely on the Fishman preamp to set the tone).

Aside from these two factors I think it's kind of a crapshoot. I hear tell that magnetic pickups don't have the feedback problems that piezo pickups or mics have, but I've never tried a magnetic pickup. Piezo pickups and mics all have feedback issues to varying degrees.

Anyway, good luck with it.