HapiCmpur said:
I see what you mean (I think). From what little web research I've had time to do, it appears that the HD has scalloped bracing and the D doesn't. I'd really like to get a D and an HD together in the same quiet room for a few minutes to see what kind of difference those scallops make.
In the 1940's-50's, they moved the bracing closer to the bridge and stopped scalloping the braces. There are two reasons for this: first, because scalloping braces is (or was - they may be doing it with a CNC these days, though I don't know for sure) is a highly skilled and time consuming process, which of course translates to an expensive process; second, they were getting complaints from the field about excessive BBB (behind the bridge bulge). BBB, while unsightly, is common, but people were complaining, and I suspect they were also spending more money than they wanted to on warranty repairs (Martin has ALWAYS stood behind their guitars, and their warranty is the gold standard in this or any other industry - within the last 5 years we have done warranty work on Martin's built in the 1920's. When they say they are warranted for the life of the original owner, they MEAN it.) So, the moved the bracing to a more structurally sound part of the top, and they made the braces heavier by not scalloping.
I've played some great guitars built either way, and I've played some dogs either way (including a first year D-28 that was completely BLAH - although it came in unplayable, so it may have just needed some time to recover from the neck reset and bridge reglue. Old guitars usually need a few months after repairs like that - particularly when you use hide glue, as we do on any instrument of that vintage - but it was still a really bland $30,000 guitar. It was that guitar which made dad call up our insurance broker and double the coverage we carry on customer guitars). There is so much variation on guitars from that era that it really is impossible to say that the sound is coming from one thing or another. The only thing to do is just try them all, and pick the one which speaks to you in your own voice. In the end, it is all about what sounds good to you.
Light
"Cowards can never be moral."
M.K. Gandhi