Experimenting with V bracing using an Ammoon kit

I am a hobby maker and have previously posted the use of an Ammoon kit (Amazon/Ebay) as a shortcut/cheap way to investigate a new soundboard bracing system.

https://forum.ukuleleunderground.co...6-Ammoon-uke-kits&highlight=ammoon+soundboard

A few members have already posted images and impressions of their versions of V bracing. I have just used an Ammoon Zebrawood tenor kit to see/hear whether there are possibilities with this system. As outlined in the above post, the laminate soundboard was removed and replaced with a V braced soundboard.

I made the soundboard from Engelmann spruce, 1.8mm thick, also using Engelmann for the patch (1.8mm max) and most of the bracing. The top tranverse bracing is there to be tied to the neck block in case you are wondering why I’ve used 3! The V bracing is 4mm wide and max 5mm high. It was pared down until I felt the tap tone and stiffness to be satisfactory.

This is the first instrument where I have used plastic purfling and binding. The instrument is finished in spray can polyurethane over shellac and strung with Seagur fishing line.

The instrument feels and sounds a little different to all my previous instruments but it's not so different! It seems more responsive and clearer though the sound is perhaps not as rich: maybe it has a less complex sound. It’s as loud and has as much sustain as my other ukes but seems to require a lighter touch to play.

When developing a new system, I’ve found a few different designs are needed to home in on the best response. I think I’ll be trying another version of this on another Ammoon kit to see if it results in an instrument that's a step change away from where I am now.

I like the new top better.

Last night at my regular uke meet, several people played this uke. The consensus was that it was clear and responsive, a little lute like in sound and whilst not bright, lacking in bass response.

This morning I set about trying to improve the response. Flexing the top by pressing on the bridge wings showed there seemed to be adequate flexibility both along and across the soundboard. The light touch required to play the instrument also suggested the top was not tight ( not too stiff). However the lack of bass suggested material needed removing somewhere.

My first move was to reduce the main V bracing adjacent to the soundhole, then to slightly reduce the transverse brace below the soundhole. As expected, there was no noticeable change but it was easy to do and hence worth a try.

I don't always use a bridge patch on my fan braced tenors and thought maybe this was too big. I tried removing material from both ends of the bridge patch. This led to the sound becoming fuller, richer and with much more bass: it's made a huge difference to the way the instrument sounds. It's now very similar in sound to my fan braced instruments.

I don't know how the pros modify bracing through the soundhole but here's my method. I use a mirror and lights inside the box. If it's a spruce box then, in a darkened room, its easier because the internal light illuminates the bracing and it's possible to see where you are.

I attach an eraser on the end of a cranked builders brick pointing tool and wrap it with 80 grit sandpaper. I tape around the soundhole to prevent damage and carefully sand away the required area inside the box with this tool. Clearly some parts are easier to reach than others and the position of the eraser may need to be adjusted.

This is very interesting. Has anyone else experimented with V-bracing?

greenscoe

I have experimented with the v-brace idea. In fact I just completed one this week. From your picture I see you added more bracing at the lower bout. Your bridge patch looks quite large. I use a .018 carbon fiber material and add no other bracing to the "V". The strings are still stretching but I am VERY happy with the results. Very crips highs with good bottom tones and the sustain seems very good. So far I like it but it will take awhile to see how it ripens and how stable the top is after some time.

Tom

tparse:

It's good to hear that you are happy with your V bracing. I have no experience with carbon fibre so can't compare the stiffness of your patch with my spruce patch.

I agree that my bridge patch is probably too large: its only 1.8mm max thick and tapers to almost nothing at the outer edges but still it appears I overdid it. As stated above even more thinning improved the low end. As for the 2 extra braces they are only 4mm wide and max 2mm high, but next time I'll omit them. As a first stab I'm now happy with the sound of this instrument.

Some players of the Taylor V braced guitars commented on the lack of bass when compared to X bracing but reckoned there was a crisp and clear response all the way up the fretboard. My instrument is certainly crisp and is good to fingerpick. I need time to see whether this ends up being one I play regularly.

saltytri said:

This is very interesting. Has anyone else experimented with V-bracing?

Click to expand...

Below an experimental V braced spruce top. Sound is not that great. Also missing some bass side volume. I think it is over braced and could go much lighter. Structurally sound with no bridge movement.

Here's a pic of the v-bracing I installed on the Redwood top for my 23" scale nylon string tenor guitar. The braces look quite fat here, but I shaved them down considerably before gluing on the top. I made a string-through bridge, with the strings knotted and pulling on the bridge plate from below. The completed instrument has a lot more punch than any of my other 4-string instruments, and the bass response is excellent.