"Thump"-sounds when amplified

MichaelSC · #1 04-02-2006, 12:04 PM

Hi.

I know that this probably has been discussed several times, but since i suppose the answer might differ depending on the specifications of the setup, I've chosen to make a new thread.

I have just bought a shadow pick-up (SH SB-02, piezo-pickup, same type as the bass max, just lower quality i quess), and when I wire up my bass and play, it has these "thump"-sounds when pizz'ing, especially from the low c and down - in my opinion I have to much "pizz-sound" and too little tone. It is also difficult to get a decently authentic and soft tone (though this might be due to the p.u.), and I can't really EQ it away, since i have some bad feedback-problems. If it is called feedback, when using piezo.

You have some suggestions?

I (unfortunately) play a 120W quitar amp of the brand "Stingray", and run the signal through a Boss CEB-7 equalizer-stompbox.

Edit: typos

fdeck · #2 04-02-2006, 12:58 PM

Nothing can be diagnosed until you get a preamp, or are assured that your pickup is feeding an input impedance of at least 1 MegOhm. After that is settled, then it's just a fact of life that no two basses are the same in terms of what pickup sounds good. Finally, if you are using a guitar amp, when you play loud low notes, then you are likely to be overdriving the speaker.

MichaelSC · #3 04-02-2006, 03:00 PM

I know that a preamp is unnecessary with my pick-up so that can't be the problem. And when i play low notes, the amp doesn't peak ord tend to make an "overdrive"-effect, and I have used the amp with my electric bass to with no great problems.

mje · #4 04-02-2006, 07:16 PM

fdeck may well have the answer. There are many possible sources of the proble. The shadow bass pu is simply a piezo bender coated with pvc. If it's not in there firmly, it can decouple and rattle at low frequencies. How do you have it mounted?

Bruce Lindfield · #5 04-03-2006, 02:49 AM

I'm surprised that nobody has mentioned that a 120 watt guitar amp is just not going to cut it for amplifying Double Bass - most guitar amps are "coloured" and emphasise a certain part of the audio spectrum to make guitars sound better.

For DB you need amplification and speakers that cover a wider range and go down lower - plus you need more power to amplify bass frequencies without distortion.

MichaelSC · #6 04-03-2006, 04:59 AM

Quote:

Originally Posted by Bruce Lindfield

For DB you need amplification and speakers that cover a wider range and go down lower - plus you need more power to amplify bass frequencies without distortion.

Yes, I probably had expected a response like that. I am trying to get my old bass rig back, but unfortunately it's with a 15" and a 12" speaker, so I'm considering investing in a Behringer BB 210 Classic Tone (http://www.behringer.com/BB210/index.cfm?lang=ENG)
But would you consider this to be a good investment? As far as I've understood from surfing the rest of the archive is that with DB fairly little speakers would be an advantage.

If i get a feedback-killer would I then be able to use my EQ without having to worry about feedback?

Edit: changed link

Bruce Lindfield · #7 04-03-2006, 05:21 AM

My personal opinion is that what you are referring to would be a good rock bass guitar setup - but not really suited to a good Double Bass sound.

Also - if you are trying to get a lot of volume from DB with such a set-up - then feedback is going to be a peotential problem.

PS - it will help people to help you, if you fill in your profile!!

MichaelSC · #8 04-03-2006, 08:34 AM

Quote:

Originally Posted by Bruce Lindfield

My personal opinion is that what you are referring to would be a good rock bass guitar setup - but not really suited to a good Double Bass sound.

Okay, but then what would be a decent cabinet for both EB and DB at an affordable price?

Quote:

Originally Posted by Bruce Lindfield

Also - if you are trying to get a lot of volume from DB with such a set-up - then feedback is going to be a peotential problem.

Okay, but what might a solution be? Can't a feedback killer make any difference?

By the way, I have filled in my profile now, hope that'll help a bit.

Bruce Lindfield · #9 04-03-2006, 08:39 AM

Quote:

Originally Posted by MichaelSC

Okay, but then what would be a decent cabinet for both EB and DB at an affordable price?

I don't know - suggest you search this forum.

Quote:

Okay, but what might a solution be?

Err...is there one ? Buy an EUB?

Quote:

Can't a feedback killer make any difference?

I didn't know there was such a thing!

Quote:

By the way, I have filled in my profile now, hope that'll help a bit.

Good!

bolo · #10 04-03-2006, 09:05 AM

Hi MichaelSC.

When I first read the title of your thread, I thought of something else entirely.

When your plucking finger comes to rest on the string below the one you just played, does it thump?

When I first started playing upright I had a BassMax. Sometimes I would hear this weird thumping, especially on fast songs. I didn't know much about right hand technique for DB at the time. I eventually discovered after I plucked a pizz note, my index finger would thump into the next string. I think both types of wing-mounted pickups that I have used can sense this type of string vibration quite convincingly and can send the resulting signal to your amp.

Nowadays I pluck the string quite differently, and I know how to lessen or eliminate that type of thumping sound.

Just another far out thought.

MichaelSC · #11 04-03-2006, 09:13 AM

Quote:

Originally Posted by bolo

Hi MichaelSC.
When your plucking finger comes to rest on the string below the one you just played, does it thump?

No, I don't quite think that might be the problem (though I do hit the string below), because when i pizz in a more classical kind of way, where the is weaved away from the strings as if hilding a bow, it still makes the sound.

Moreover, it only makes the sound on the lower strings (A and E)

**Chris Fitzgerald** · #12 04-03-2006, 10:29 AM

Have you tried muting the afterlengths of the strings? This usually cleans up a lot of amplified ugliness. To test for this, have a friend hold the afterlengths tightly while you play and see if the sound still happens.

Learning to amplify a doublebass is a lot like learning to live with an older VW....

Bruce Lindfield · #13 04-03-2006, 10:34 AM

I agree with Chris's last point - I've found all sorts of differnet problems amplifying DB in different rooms - but I'm pretty sure I'd have even more if I was using a Carlsboro Guitar amp....

MichaelSC · #14 04-03-2006, 03:17 PM

Quote:

Originally Posted by Chris Fitzgerald

Have you tried muting the afterlengths of the strings? This usually cleans up a lot of amplified ugliness.

Yeah - I've heard about that, but how is that done practically?

Quote:

Originally Posted by Bruce Lindfield

I agree with Chris's last point - I've found all sorts of differnet problems amplifying DB in different rooms - but I'm pretty sure I'd have even more if I was using a Carlsboro Guitar amp....

Hehe... point taken

as mentioned, I'm working on getting my bass rig back to my place (Have I mentioned that?)