In this instructable we'll build a terrific sounding tub bass that is highly suitable for studio recording and/or live performance. Build time is less than one hour using very simple tools and around $30 in materials. An optional contact microphone can be added to amplify the instrument.

On this step I've included some samples of the instrument in use. All three mp3s are the same snippet, recorded three different ways:

"tub_bass_mic" is an acoustic recording using a regular old microphone, as evidenced by the background noise and sounds of people walking around in my studio

"tub_bass_contact_mic" uses the contact microphone - squeaky clean and provides very different tone than a normal acoustic microphone

"tub_bass_mix_with_eq_and_reverb" - a mix of both mics with some EQ and reverb, this is probably how I would use it on a record

Sweet!

Step 1: Overview

The tub bass is a simple and venerable folk instrument that can be used to fill out the low end of many styles of music. There are two principle areas of basic tub bass design wherein one may encounter differences of opinion: the string material and the neck construction.

Our bass makes use of plastic-coated galvanized steel cable (a.k.a. plastic-coated aircraft cable) for the string - this will be nearly impossible to break and provides far superior tone and playability to parachute/nylon cable. The plastic coating allows you to play the string with bare hands.

Our neck is unattached and pivots on the rim of the tub. Notes are thus created by flexing the neck to change the amount of tension on the string. This makes for a more intuitive playing style than an instrument with a fixed neck and fret board, but it will take some practice for your muscles to learn how to hit and hold specific notes. A used-up wire spool acts as a slide-able capo, allowing us to play in different pitch ranges/keys.

Our instrument also adds an optional pickup for amplification in the form of a contact microphone. I made mine from scratch using the recipe from Nicolas Collins' excellent Handmade Electronic Music (essential reading for instrument makers/hackers), but readymade contact mics are also available on the cheap.

This is the same tub bass that is used by The Asker Brothers to achieve their signature thwonk-a-donk sound. Let's begin!

Step 2: Materials & Tools

Materials:

One tub, our resonant chamber.

One broom/mop handle, the neck. This should be un-tapered so you can make use of a sliding capo.

One used-up wire spool, the capo. Make sure it's a good fit on the neck - you'll need a little extra space for the string when fitting the capo over the neck. I found that a standard-sized wire spool was the perfect fit for a standard broom/mop handle.

Plastic-coated aircraft cable, the string. This is the only part you're not likely to find in the local hardware store. I ordered mine from webriggingsupply.com, part no. 02C030477. We'll be stripping the coating on the ends of the string to thread it through the neck/tub/hardware, and the width of the interior steel portion of the cable should be 1/16. This width of cable has lovely tone. Get at least six feet of cable.

Ferrules and Stops, cable hardware for 1/16 steel cable. This is the hardware we'll use to attach the string to our neck and tub. I was able to find packages of National item #N283-846 at the local hardware store, two of those put me in business.

One jar lid, the washer we use underneath the tub when attaching the string.

Optional: one contact microphone to act as a pickup for amplication. Make your own or buy one.

Tools

Dremel tool. We'll be using the disc sander bit to cut/shape the aircraft cable and to make a notch in the bottom of the neck. The 3/32 drill bit will be used to drill holes for threading in the neck, tub, and jar lid.

Wire stripper. Used to strip plastic coating off the ends of our string and to crimp the cable hardware.

A saw. To cut off the little screwy section of our broom/mop handle.

Sally forth!

Step 3: Prep String for Neck

Strip ~5 inches of coating from one end of the cable. You'll need to do this in two inch sections. When stripping the coating, the end of the cable may become frayed which will make it hard to thread it through the neck/tub/hardware. If this happens, use the dremel tool with the disc sander bit to cut off the frayed section. The broad section of the disc sander bit can then be used to shape and sharpen the tip of the wire, giving you a nice pointy end that will be easy to thread.

Step 4: Attach String to Neck

Drill a hole in the end of your neck using the 3/32 drill bit on your dremel tool (or drill). Thread the stripped section of the cable through the hole in the neck. Secure the cable by using the cable hardware: thread it through one section of the double-barrel ferrule, then the stop, then back through the other section of the double-barrel ferrule. Crimp the ferrule by lightly mangling it at multiple points with the teeth of your wire stripper (or use a real crimper if you have one). This will make the ferrule press firmly down on the cable, holding the string in place.

Step 5: Prepare Neck

Cut the threaded screw section off the end of your mop handle using a saw. Then make a notch in the bottom so the neck can sit securely on the lip of the tub.

Now to measure and the cut string: Put the notched end of the neck on the lip of the tub, as if you were playing it. Hold the unattached end of the string to the center of the tub with your hand. The string should be taught when the neck is perpendicular to the ground - find this length then make a mark 10 inches further down the cable (we need some slack to pass the string through the tub and loop it through the hardware). Cut the string using the disc sander bit on the dremel tool and strip off 10 inches of coating, similar to what we did to the other end of the string.

Step 6: Prep Tub

Drill a 3/32" hole in the center of your tub and jar lid. Remove the handles from the tub so they don't rattle when playing the instrument.

Now attach the string to the tub: Thread the cable through the tub, jar lid, and ferrules. Make sure your string is the correct length before securing the ferrules: test it by putting the neck in place and pulling lightly to determine exactly where the hardware should be attached on the stripped end of the cable.

This is the part of the instrument that will be pulled on the hardest, so I used two ferrules to increase the grip on the cable. Once you're confident about the string length, crimp the ferrules to secure a good grip on the cable.

Step 7: Attach Capo and Contact Mic

The empty wire spool can slip over the top of the neck and past the connecting hardware. It can now be slid up and down along the string to change the pitch range of the instrument. The optional contact microphone will be placed between the tub and jar lid - a piece of tape will hold it in place. The contact mic adds lots of high-end tone to the instrument and allows you to play much louder, useful in performance situations. If the contact mic is squeaky try adding some Vaseline.

And that's it! The world is yours to rumble with tubby goodness. ENJOY.