For those of you that own a SD 40, just curious what strings you found that brought out the best tone of your guitar? I am currently trying Medium light Martin Retros on mine. I have had Elixer lights on it before. The Retros are all right for strumming but to metallic sounding when flat and finger style playing. I have figured out that putting medium strings has brought out the loudness of this style of guitar, but fingers are not so sure they like these bigger strings. lol

I'm planning on trying medium PB D'Addario's on mine at the next string change. I plan on using this for un-amplified song circles as soon as spring hits so looking to get max volume. Probably swap them in a few days. I'll report back.

I don't have an SD40, but another "in-between" set of strings I like (and I DO like the Martin Med.-Lights MA545) is D'Addario EJ24 "True Medium Gauge". The strings are .013, .017, .024, .032, .042, .056.

This gives you nice thump on the low E and also gives you less twang/thinness on the high E and B plain strings. The tension is a little less than Martin's Med.-Light set, too, I believe. They sound good and last well...and usually aren't expensive.

I've owned a few SDs, but not the 40. My advice is always the same, no one can tell you what pants feel comfortable on you or what foods you like the taste of. They can't tell you what strings you'll like the feel or sound of either. Strings are the cheapest, easiest way to customize your guitar to your tastes so get a variety is types and sizes and use use a new one each time you re-string. The cool thing is different guitars respond uniquely to the same strings so you can always do this, no matter how experienced you are.

String selection is such a selective, biased discussion. I can't comment on the SD 40 since I don't own one but here's my feedback based on my experience.

I have tried lots of strings over the years and always gravitate back to D'Addario light gauge EJ16 phosphor bronze for all of my guitars. Having said that, last night I went on on a limb and put DR Rare light gauge strings on my OM35. My son bought me a NEO-D Humbucking soundhole pickup that we installed and ran through my Fishman Loud Box mini amp and the OM sounded great. My Larrivee 12 string sounded really nice through the amp too.

At $6 to $7 a set, strings offer an inexpensive way to experiment. I think a lot of builders string up their guitars with coated strings in anticipation of the fact that guitars my hang on a dealer's wall for a while.

Good luck with your research.