Vicious_Squid

Here's a better video: (no amplification or volume boosting)

It's finished! - Archtop upright bass made from a wheelbarrow. neck-thru (cigar box style) made from a solid mahogany door frame. Wheel left on for portability. Technical specifications: * 67 inches tall (1.7 metres / 5.58ft) * 3 strings (weedwackers) tuning: EAD * scale length 41 inches (104.14cm) w/ adjustable bridge * action 0.5 inches * neck width 3.5 inches (8.89cm) * 1.75" diameter body-coloured foam bumpers * sound post and f-holes * bridge piezo pickup (not pictured) Video: https://youtu.be/sYVip9Yxt9w Build album: https://photos.app.goo.gl/jQTKj1hzPv8G117XA Apologies for starting a new thread but I couldn't find a way to edit or remove my old one. If moderators could please do that I'd be very grateful.

My wheelbarrow bass is also arched

The front / table is attached to the ribs with screws and it will be glued next week when proper strings go on (right now the strings are just baling twine as a test - pretty loud actually!) I'd like to see photos of what is visible of the inside of your double bass through the F-holes if you wouldn't mind sharing. Yeah, tiny bridge 🙂 -- I don't know the physics either. In fact I've no idea what I'm doing, but it seems to be working so I'll just carry on!

Update: IT WORKS! (and has a 43" scale length)

Thanks for your post! The head is actually angled backwards by 10 degrees but not visible very well in the photo. I've attached a better picture to this post, you can clearly see the difference in angle between the two sections (neck and pegbox) - the mathematics check out. I'm an electric bass-player so my design is based on a 3-stringed hybrid of an electro-acoustic bass (ovation style) and an orchestral upright bass, so it will have a double-bass bridge. I'm not sure if I'll need a bass bar however, since the resonant cavity is huge and I think the hardwood ribs will suffice. As you quite rightly pointed out, it has a sound post (1.5 inch wooden dowel) which will probably end up being glued to the face-plate. Since you're a fellow engineer I'd be happy to send you the technical drawings via email (don't want to share them here yet) and would welcome your advice since I'm really just making this up as I go along.

Today I made some hardwood ribs to add stability and provide an anchor point for the face-plate whilst also stopping it from contacting with the centre bar (resonant gap)

Check out this beautiful concerto on a (traditional) 3-string double bass composed by Bottesini (a double-bassist pioneer in his time and one of my heroes): https://youtu.be/QgZ_-f7pVk4

During the 17th and 18th century the bass family diverged into two lines; the four string and the 3 string, with the 4 string version being used in Germany and the 3 string version being used in France, Italy, and England. t was thought that the 3 string version had better tone. Then around 1800 there was a migration away from the three string version and then an abandonment a generation later when the old teachers died off. 3-string contra-basses are still pretty common in folk ensembles all over Europe. Tuning for a 3-string (traditional) double bass is E A D (or E A G) and that's all I need. Also means fewer moving parts and less risk of breakage by overtensioning or overstressing the neck and head. It is fully portable - has handles which are removable (not visible in the pics)

So here she is, my creation: an upright bass made from a wheelbarrow (for ultimate portability!) - they said I was mad! This instrument when finished will have a 43" scale length and will wear weedwacker (rockabilly) strings. Note about this pic: This is not final positioning of the head-stock, just clamped to get a rough idea. Full album is available here for your perusal: https://photos.app.goo.gl/jQTKj1hzPv8G117XA