Action & relief for C# open setup

[lamanoditrento]

I thought I had posted this thread the other night, but it looks like I closed the window before submitting the post.

Anyhoo, that post was ramble; as a second swing: I am setting up a multiscale that the client would like the setup to C# open. The scale is 679. mm bass and 647.7mm on the treble (26.75" & 25.5 in Myanmarian units).

I had an idea and a complicated spreadsheet that used Mottolla's calculations for compensation https://www.liutaiomottola.com/formulae ... sation.htm which overlayed saddle compensation for alternative tunings etc. But which t ended up being a complete waste of time because the action and relief I was targeting were for Open E standard tuning. That is entirely unrealistic for C# open standard.

So, ignoring my overly complicated spreadsheet, given a C# standard open tuning as the default tuning, how would you set it up?

[kiwigeo]

My multiscale commission built for Kym was to be used in a variety of alternate tunings. I ended up just setting up for standard tuning.

You're compensating at saddle only or saddle and nut?

[kiwigeo]

Trent have you tried jigging up a spreadsheet based on Trevors procedure for mathematically modelling the neck/fretboard?

[lamanoditrento]

My multiscale commission built for Kym was to be used in a variety of alternate tunings. I ended up just setting up for standard tuning.

You're compensating at saddle only or saddle and nut?

It plays beautifully in standard open e at the moment but it just can't work in C# standard. Funnily enough, given all the different scale lengths I did a 'simple intonation fix' and with a 5mm saddle I had intended on doing a conventional saddle compensation with a b string cutoff. The problem is not the compensation, the problem is the desired action and relief. The lower tuning means the string oscillation is larger.

Does anyone have a calculation for the relationship between tension frequency and oscillation?

[Trevor Gore]

The amplitude of oscillation is entirely dependent on the pluck displacement. Of course, it takes less force to displace a lower tension string for the same oscillation amplitude of a higher tension string. For the same feel you have to go to a higher tension string set, i.e. heavier strings, which is normal for lower tunings. If you want to use a lot of different tunings on the same instrument, you'll have to find a suitable compromise string set, likely heavier than what you have on now.

[lamanoditrento]

The amplitude of oscillation is entirely dependent on the pluck displacement. Of course, it takes less force to displace a lower tension string for the same oscillation amplitude of a higher tension string. For the same feel you have to go to a higher tension string set, i.e. heavier strings, which is normal for lower tunings. If you want to use a lot of different tunings on the same instrument, you'll have to find a suitable compromise string set, likely heavier than what you have on now.

Ah! Thanks Trevor, so succinctly clarifying! All the convoluted things I had been calculating and didn't think to make the string weight a variable. I had raised the action and relief but it just seemed ludicrous. Excellent, I have 13-57 on so will try maybe something like 15-67 and go from there. Mucho gracious!

[jeffhigh]

Keep the relief low (4 thousandsths of an inch ) IMHO there is nothing to be gained by increasing relief
Probably 14 to 64 strings.