Double Bass feedback

[kipperwig]

Hi, I've recently started playing double bass, having been and electric player for around 5 years. So far i've been playing acoustic gigs (bass and piano, or bass and acoustic guitars) and it's not been a problem to amplify the bass, Usually DI'ed to the PA using Markbass LMII as a preamp.
My bass is a 1960's german (i think) laminate with pirastro jazzer strings and a Shadow SH950 pickup.

I've just joined a band where i'm going to have to play at a much louder volume to compete with a kit and 2 electric guitars. I also want to use some distortion. I know this is asking for trouble, but i've seen it done, so it's possible.

I had first rehearsal with the band a few days ago, and was really struggling to get the volume without feedback.I could achieve around the same volume with clean and distorted sound. The distorted sound would squeal as soon as i stopped playing, but a gate mostly sorted that out.
I was playing through a small kickback type amp(i cant remember what it was) and by the time id got maximum volume, by adjusting the eq on that, the tone was awful, and the rest of the band still had to play considerably quieter for me to be heard.
I taped the F holes up with some gaffa, that helped a bit.
another thing i noticed is that the bass was resonating a lot with the drums, so the kick and snare would set off feedback.
My amp is a LMII and markbass traveler 2x10 cab, though i will be mostly playing DI'ed or through whatever amps will be at gigs, as i don't have a car so can take everything to gigs.


A few options i think i can try are;

use a preamp, e.g. fishman platinum eq. (the phase reverse option being very helpful from what i understand)

Try a magnetic pickup

EQ. - 31 band graphic or a decent parametric, or a feedback destroyer.

Fitting a second sound post, though i don't really want to compromise the acoustic sound of the bass if possible.


Which of these options, ( or any other ideas) would you try first?
I've also read that dampening the strings between the bridge and tailpiece can help, so I'll try that when i get hold of some foam.

I know this is a problem thats going to take some time and experimenting to solve, and that theres no easy answer, but i would be very grateful for any advice you can offer.

cheers, Rob.

Edited March 31, 2010 by kipperwig

[wulf]

Might you need a second bass? If you are competing with electric guitars, a drum kit and adding distortion to your own tone then do the nuances of acoustic tone matter. Perhaps something like a Stagg EUB would do the new job better without modding your existing bass in a way that would affect it for more sedate gigs?

Wulf

[henry norton]

How about a notch filter?

[slobluesine]

had similar problems to you Rob and did the following...

got an Underwood Pickup and a magnetic, Kent Armstrong supplied the magnetic for £75

of ALL the pickups i've tried the Shadow 950 was the worst for feedback

fitted second soundpost

got rid of the Mark Bass amp and got an EA Doubler with dual inputs, notch filter, variable Phase etc

this is what luther Steve Laws did to my Bass...

fitted Fixed bridge, this definitely helped, fitted a damped sound post under the G string at a point which gave the most damping (trial and error this one). I also fitted a standard soundpost directly under the bridge foot on the E string side on the inner side of the bass bar

i can get stupid loud now

Bergantino cabs really help too i think, maybe it's the rear porting ?

[endorka]

One of the biggest feedback causing problems with amplifying a DB is that the sound coming from the speaker can get into the body of the DB, which of course causes feedback. A quick and cheap solution for this is to elevate the speaker cabinet way high - as in on a milk crate on top of a table high - to get the sound above the body of the double bass and into the audience. Being at this height also helps it get into your ears, so you should definitely be able to hear yourself more clearly.

There will be people who express concern that elevating the cab from the floor will ruin the low frequency response. Ignore them.

Another tip is to remove most of the bass frequencies from your speaker, which cause the "whoooommmmm" type feedback, and to rely on the front of house (if there) to supply the low end. Sending the DI pre-EQ should allow this. If there is no front of house you may have to settle for a compromise in terms of tone/volume.

Jennifer

[kipperwig]

Thanks for the quick replies guys.

I really want to be able to use my double bass if possible, i dont really fancy an EUB.

would i get better results with a notch filter rather than 31 band eq?

slobluesine, do you use the underwood and magnetic blended, or just the magnetic when you need volume?
it's bad news that you found the shadow to be the worst pickup for feedback!

Do you think it's always going to be a battle without the soundpost mod? how much is the acoustic tone sacrificed?

I was planning on splitting the signal for the pa. I was having more of a problem with high mid frequencies than the low end, though i did take out quite a lot of bottom. And i expect the frequencies will vary depending on the room, and the amp/monitors.
elevating the cab seems like a good idea, though i guess not always possible.

[slobluesine]

i mostly use them mixed together, if theres a nice big PA i send the Underwood to that and use the mag for monitoring, lots of options with with two pups

my bass is pretty dead acoustically with the two soundposts but i never play it quiet so not such a problem

only way is to try things with your Bass, kick bass drum was the frequency that set my bass off,

Unfortunately the bass drum usually thumps out around 75Hz which is very close to the second harmonic of the fundamental of my Bass apparently

dont forget most Drummers and Guitarists want to hear a Fender

[TheRev]

+1 for getting you cab up as high as possible - at ear level if you can.

At the moment I'm having reasonable success with downward firing cabs a la Acoustic Image. I screwed feet onto the front corners of my BFM Omni10 so that it sits about 3cm off the floor 'face down'. Putting it in corner really brings out the bass without feedback and the whole sound is quite nice and omnidirectional. You do need to be careful with hollow stages though, as it can quickly get overpowering.
I'm going to try it with a Gramma pad at some point to see if that adds consistency to the sound.

Dave

[keeponehandloose]

Make sure that the soundpost /bridge are positioned correctly to each other.
The bridge should have its back edge half over the soundpost.
This next one works for me every time,,,,,,,,,,,,,get a small beach ball and put it through the soundhole on the bass side,
pump it up ,and it has the same effect as a second soundpost ie damping the bass bar.
Just be carefull with positioning as you pump it up or you may move the soundpost.
The hardest part of this is fending off comments from your band mates..

[OutToPlayJazz]

Quite strangely, I get the same problem using my double bass/fishman preamp with my Roland BassCube 100. Horrendous feedback nearly all the time. Now the Warwick Triumph upright doesn't do this & strangely there's no feedback with the same DB setup into my Genz Benz. The bass I'm using is hugely resonant so you do need to keep your hands on the strings when not playing, but it sounds perfect with the Genz setup.

As for sound post setting, no the sound post should not sit under the bridge foot. That will strangle the sound. There needs to be a small gap between them. A luthier will spend some time moving the soundpost around, as all basses are different and respond in sonically different ways.

Here's a quick excerpt from a setup guide...

Proper soundpost position is in line with the center of
the foot on the bridge's G string side and in the neighbourhood
of 1/2" to 3/4" lower (towards endpin).

Correct positioning of the bridge is also important. You need the centres of the feet lined up with the "nicks" of the f-holes.

Rich.

[kipperwig]

Wow, a beach ball! that sounds like a great idea, i think i'd be scared of knocking the soundpost. Anybody else tried this???
My soundpost has recently been set by a luthier. is the best position of the soundpost for acoustic tone, not necessarily the best position for amplifying?

[keeponehandloose]

[quote name='OutToPlayJazz' post='795028' date='Apr 3 2010, 01:18 PM']Quite strangely, I get the same problem using my double bass/fishman preamp with my Roland BassCube 100. Horrendous feedback nearly all the time. Now the Warwick Triumph upright doesn't do this & strangely there's no feedback with the same DB setup into my Genz Benz. The bass I'm using is hugely resonant so you do need to keep your hands on the strings when not playing, but it sounds perfect with the Genz setup.

As for sound post setting, no the sound post should not sit under the bridge foot. That will strangle the sound. There needs to be a small gap between them. A luthier will spend some time moving the soundpost around, as all basses are different and respond in sonically different ways.

Here's a quick excerpt from a setup guide...

Proper soundpost position is in line with the center of
the foot on the bridge's G string side and in the neighbourhood
of 1/2" to 3/4" lower (towards endpin).

Correct positioning of the bridge is also important. You need the centres of the feet lined up with the "nicks" of the f-holes.

Rich.[/quote]
Im not saying that the soundpost is best in that position for acoustic tone,it does choke the sound slightly,but it works best for amping.

[slobluesine]

[quote name='keeponehandloose' post='795082' date='Apr 3 2010, 02:48 PM']Im not saying that the soundpost is best in that position for acoustic tone,it does choke the sound slightly,but it works best for amping.[/quote]


that's the point in putting the soundpost almost directly under the bridge it deadens an oversensitive Bass and helps with feedback

double soundpost almost kills the Bass acoustically but has even more of an effect on reducing feedback

some players will have seperate Basses for acoustic and amp'd situations, same way as BG players have multiple Basses i guess

[BigBeatNut]

[quote name='slobluesine' post='795116' date='Apr 3 2010, 04:19 PM']double soundpost almost kills the Bass acoustically but has even more of an effect on reducing feedback[/quote]
If the bass becomes [i]that[/i] accoutically dead ... would there be a detectable difference between that and an EUB ?

[slobluesine]

[quote name='BigBeatNut' post='795222' date='Apr 3 2010, 07:30 PM']If the bass becomes [i]that[/i] accoutically dead ... would there be a detectable difference between that and an EUB ?[/quote]


i think it will depend on the Bass, most EUB's sound like Fretless BG's to me, i can still get a nice Upright tone, the Bass is not TOTALLY dead just kinda tighter and not affected by LOUD drummers, Guitarists quite so much

it's definately worth experimenting with if feedback is a problem, fairly easy job to reverse too

[endorka]

[quote name='kipperwig' post='795037' date='Apr 3 2010, 01:23 PM']Wow, a beach ball! that sounds like a great idea, i think i'd be scared of knocking the soundpost. Anybody else tried this???
My soundpost has recently been set by a luthier. is the best position of the soundpost for acoustic tone, not necessarily the best position for amplifying?[/quote]

In terms of any setup technique, the more efficient the instrument becomes at resonating, i.e. gets a louder acoustic tone, the more prone it is to feedback for exactly the same reason, i.e. increased resonance. Through constant setup tweeks on my DB I have direct experience of this.

However, I can say that even though my DB is now working very efficiently acoustically, it still amplifies well through use of various techniques I mentioned earlier in this thread, loud enough to get a reasonable onstage volume with a disciplined rock band, for example. Whether it would be loud enough for a rockabilly or very loud rock band, I am not sure, and perhaps more aggressive feedback reducing techniques would be required.

Jennifer

[kipperwig]

[quote name='endorka' post='795283' date='Apr 3 2010, 08:45 PM']In terms of any setup technique, the more efficient the instrument becomes at resonating, i.e. gets a louder acoustic tone, the more prone it is to feedback for exactly the same reason, i.e. increased resonance. Through constant setup tweeks on my DB I have direct experience of this.

However, I can say that even though my DB is now working very efficiently acoustically, it still amplifies well through use of various techniques I mentioned earlier in this thread, loud enough to get a reasonable onstage volume with a disciplined rock band, for example. Whether it would be loud enough for a rockabilly or very loud rock band, I am not sure, and perhaps more aggressive feedback reducing techniques would be required.

Jennifer[/quote]


Jennifer, what gear do you use? which pickup , preamp/amp , anything else?

[endorka]

[quote name='kipperwig' post='795291' date='Apr 3 2010, 08:54 PM']Jennifer, what gear do you use? which pickup , preamp/amp , anything else?[/quote]

I use a Realist pickup into an Eden WT330 amp, which is part of the cxc110 combo. I don't use an external preamp as the preamp on the Eden has a sufficiently high impedance for acoustic instrument pickups - one megaohm, I believe. I give a pre-EQ DI to the front of house from the DI socket on the back of the Eden.

There are several keys to making this work in a loudish onstage environment; first is to elevate the speaker as close to ear level as possible. When I'm going through the front of house speakers I will use my own speaker in a monitoring capacity only. In this situation I roll off *tons* of bass on my speaker, so that only the mids and highs are coming through, which is enough to allow me to hear myself and get a reasonable fix on the intonation. Once the front of house speakers are enabled, they will supply sufficient bass frequencies onstage to fill in the sonic gaps. I never have any of my DB in my own monitor wedge.

If anyone else has double bass in their monitor wedges, I also advise them to roll off the bass frequencies in a similar fashion; typically dump anything below 250Hz, and certainly below 120Hz. If they don't do this, all they will hear is a big whooommmpppfffff and no definition.

Another problem I have come across is that often what people assume is feedback from the bass actually is not. Several other common causes of bass type feedback are;

- the bass drum mic
- the floor tom mic
- acoustic guitar body
- low guitar strings resonating
- low notes on a keyboard feeding back through vocal mics.

Of course, once one of these gets going, it will typically set off your double bass as well!

Jennifer

[Pookus]

I dial out the feedback with my old Fishman Dual Parametric EQ. Find the offending frequency then cut it. Like others have said - elevating the amp works for me too.

[keeponehandloose]

I always view the fight against feedback as one of 2 ways.
The first is to use all your eq tools to stop the feedback.This is fairly easy to do,but will probably leave you with a sound you dont particularly like.
The second way is to damp your instrument as outlined above in some way, so that your eq can be used to give you a good amplified tone instead of taking out all the offending frequencies.

[BobVbass]

I can't help wondering (just about to start playing DB in a 50's RnR band so I'm sure to have trouble) whether some kind orf removable spring loaded rod that you can clip onto the front through the f hole and poke through to the back of the bass to dampen things might work - that way you could remove it when you wanted to play acoustically...

Start the generators! I feel an afternoon in the garage when my DB arrives!

[slobluesine]

heres another solution...

[url="http://www.dougsplugs.com/how-dougs-plugs-work.html"]http://www.dougsplugs.com/how-dougs-plugs-work.html[/url]

he makes them for Double Bass too

[dougal]

Has anyone tried adding one of these into the signal chain?

[url="http://www.behringer.com/EN/Products/FBQ2496.aspx"]http://www.behringer.com/EN/Products/FBQ2496.aspx[/url]

I'm guessing it'd have to be post DI to the PA. I don't know if the FX loop on most amps is pre- or post DI (I suspect pre-, which would bugger FOH sound & render this suggestion useless... What's that quote from Hitchhiker's guide where God disappears in a puff of smoke from his own logic?).

Edited May 20, 2010 by dougal

[bobmbass]

I too have started playing double bass in the past twelve months, and have experienced all the feedback problems you speak of. I had a Realist for a while, which has a high output, and seemed prone to feedback, it also seemed to distort some of the notes, maybe I didn't have it set up correctly. I play in quite a loud blues band with bass drums sax etc, so some of the subtle tones you get from a piezzo pick up probably wouldn't be heard anyway, so I bought a Schaller magnetic. I run this through a Fishman platinum pro pre amp which definitely helps having phase and notch filters, it's got a built in tuner and a boost switch as well; it's not cheap though.
In answer to Slobluesine who mentions Doug's plugs f hole covers. I have now started to make my own version in the UK, called f-its, and they work brilliantly. I have had permission from Ped to mention my website, please check it out if your interested.
its www.f-itsfeedbackblockers.co.uk
I've also recently bought a BBand electret transducer pick up, which sounds great, but I haven't had time to test it out with the band yet. For the record, I play through a Little Mark 3 and a Epiphani series 2 4x10 cab.