Tech: Amplifying a double bass

Subject: RE: Tech: Amplifying a double bass
From: Max
Date: 09 Aug 16 - 12:11 PM

I've used the Fishman BP-100 and think it's the cat's pajamas. I use it with the Fishman B‑II Acoustic Instrument Preamp (which I am not sure they make anymore) and couldn't be happier with what it gives me. I'll even throw it on another instrument now and again, like under the saddle of an old classical guitar I string up baritone with some nylon super heavy harp guitar strings. Or various cigar box contraptions I'll tinker up. Very versatile, pure sound. Love it.

Subject: RE: Tech: Amplifying a double bass
From: Cappuccino
Date: 09 Aug 16 - 10:28 AM

That's interesting... I'll do some more testing. Many thanks.

Subject: RE: Tech: Amplifying a double bass
From: Jack Campin
Date: 09 Aug 16 - 10:09 AM

For a bass instrument, isn't the speaker the part of the system that will make the most difference to the sound quality?

Subject: RE: Tech: Amplifying a double bass
From: Stanron
Date: 08 Aug 16 - 03:32 PM

A piezo pickup has to go through an 'impedence transformer' in order to sound OK. I'll skip the fine detail but some guitar foot pedals have this in built, others do not.

They all work best if there is pressure holding the pickup to the resonating surface. This is why under saddle pickups work as well as they do. String tension on the saddle presses the pickup against the bottom of the bridge.

I used to make my own pickups from piezo tansducers, intended to be beepers and available from Maplins for pennies, sandwiched between two pieces of wood and wedged under the bridges of a violin or a mandolin. I made the impedence transformer from a circuit found online. It was a 5 to 10 meg ohm input impedence FET pre amp if you want to do a search for it. It had one transistor and a small number of capacitors and resistors and ran off a 9 volt battery.

You can buy them now on Ebay, complete with with tone and volume controls for less than a tenner.

Pre amp on Ebay

How you'ld fix one of these to a double bass is a separate problem, but you could make an attachment to fit to a belt.

Subject: Tech: Amplifying a double bass
From: Cappuccino
Date: 08 Aug 16 - 02:39 PM

Does anyone have any practical experience of amplifying a double bass? I use a three-quarter size bass with Weedwhacker nylon/Kevlar strings (which are cheap as chips and, surprisingly, are pretty good!) I'm a folky picker, not a classical double-bassist; I don't use a bow or anything like that. I come to acoustic bass from many years of electric bass.

Our ceilidh band, made up largely of melodeon and wind instruments, say they like having the bass to keep the tempo. But double basses don't have natural volume (which is why there are several in an orchestra) so I need to boost the sound a bit. Double bass pickups are phenomenally expensive, so that's out; I've tried cheap piezo-style transducers instead. Through my guitar amp (which is super for my acoustic bass guitar) they give me a sound like kicking a suitcase. Through my 25w practice bass amp the sound is better, but still not as good a bass tone as I want. I suspect that through my Ashdown 180w bass combo even the cheap transducers will sound better, but that amp is too heavy to cart round all the time.   

I suspect that my best course is to ditch the idea of a pick-up, and to play through a mike positioned in front of the bass - I suspect that a bass through a microphone and a PA amp will sound far better than the transducer method.

Does anyone have any useful experience?
Thanks.