I got my 5 string 28,6" scale Ibanez GSRM25 Mikro bass tuned F#1 to D3, like the 5 lowest strings of an 8 string guitar, or 2 half steps above standard E tuning. Works well for me with how I use it, a bit more like you would a Bass VI type instrument or a baritone guitar, than how you'd traditionally play a bass, with a lot of melodic lines and chord work. As it is now I have it strung up with a gauge .100 to .032 set of strings, which due to the short scale of the Mikro bass still put a fair deal lower tension on the neck than a similar set of strings would on a regular 34" scale bass in E standard tuning. This arrangement does actually work great and I am quite satisfied with it, but non the less I have decided to experiment with putting on a set of strings with lower gauge, to see how that would work. I haven't actually received the new thinner strings that I ordered for this experiment yet, but they are a set of Ernie Ball 2837 Slinky Baritone strings, gauge .090 to .020 (6 strings, so the thinnest string I will actually use is gauge .030), meant for Bass VI type instruments. This also means that the new strings will have guitar sized ball ends, which I plan to solve by threading them through the cut off ball ends of an old set of bass strings, before going through the bridge. Tension wise on my bass, since I tune up to F# standard, the new slimmer strings will be very close to when my current gauge .100 to .032 set is tuned in E standard, actually even having ever so slightly higher tension than that, so should work perfectly fine. My own guess is, beside obviously lower tension, that the slimmer strings will give me a bit less fundamentals and more upper harmonic content, but what do people say about this? What effect does string gauge have on the tone of a bass? It might be in place to add that the mentioned strings are nickle round wound steel strings, though discussion about other types of strings is welcome in this thread as well. All opinions are welcome, but it would be nice to hear the reasoning behind them and even better if someone could provide actual scientific facts to back up their claims.