My backup acoustic guitar is a 1989 Alvarez-Yairi DY-38, a full bodied dreadnaught.
Using the same Elixir Nanoweb light guage strings on it as I use on my Martin DC-16gte, it is a great sounding older guitar. The basses are not as deep as my Martin, but I do like the more punchy sound of the Yairi. Actually, for playing rock-n-roll, I like the Yairi better than I do my Martins.
For outside gigs at parks or at the lake, I like to take the Yairi instead of my Martin DC-16gte or my Martin J-12-16. The Yairi will be going with me next year when I go to Philmont Scout Ranch for a week of chaplain and camp fire song leader duties.
Out of curiosity, I recently purchased the Planet Waves O-Port to put in my Yairi, wanting to see if it would make any difference on an already good sounding guitar.
In a word . . . YES! It only took about 10 minutes (maybe less) to loosen the strings, install the O-Port and to then re-tune.
The Yairi is just a bit louder now acoustically, and the sound is a better blend of bass, mids and highs. Plugged in, the sound is fuller, using my normal amp settings that I seldom stray from for my steel strings. I have to say that I am pleased, and feel the expense was a good one. I got the O-Port for $24.99 plus shipping.
Today I played both the Martin DC-16 and the Yairi. The characteristic brand differences remain. Nothing guitar accessory would change that. However, the Yairi more than held it's own, especially running through some Beatles, Eagles and CCR songs.
If you are playing a mid-range priced guitar, and would like to give it a "little" boost, then you might consider giving the Planet Waves O-Port a try. To my ear, it works. It comes in two sizes, and also in black and cream colors.
I do not think the addition of an O-Port would be that noticeable on the Martins. Anyway, it won't fit my DC-16gte because of the Fishman onboard pre-amp. I have a Takamine magnetic pickup in the f-hole of my Martin 12 string. I think I could adapt the O-Port to fit the 12-string with a little trimming from my X-Acto knife. The O-Port will not fit in my Taylor NS74, as a classical top is a bit thicker than a steel string.
So, I like it, but I think the O-Port is a better accessory for lower priced/quality guitars, or older guitars that need a little boost.
God's grace still amazes me . . . ><>