Thanks for sharing,
@ChillToMusic
I've found myself a nicely persevered HD565 as well, so now I have both headphones at home to test out.
First, let me say that the differences can be subtle, depending on source and material, but they are certainly notable.
For those unfamiliar with these headphones: to my knowledge the only real difference are the grills. Plastic on HD545 vs. metal on the HD565.
Due to this crucial difference in design,
@ChillToMusic is right in saying that the 545's have a more intimate soundstage and perhaps a tad more bass. Although this last observation could be solely because of the 565's wider soundstage and higher amount of treble. So it's only logical that the bass is more spread out aswell, so to speak. I would like to note that both these headphones definitely lack bass and bass impact. Like, big time. So, because of this, I've added a Schiit Loki into the mix to give both cans a firm bass-boost. Which they take like a champ! Also, on a positive note: it's nice to actually hear bass guitar notes for a change. Like the actual nuances that are otherwise perceived as dark thundering blobs (kinda looking at you here HD650).
Anyway, overall it's hard to pick a clear winner here. I was sort of expecting the 565 would be a definite step up, but really it's not. It just comes down to personal preference.
Right now I'm listening to Tracy Chapman and the 545's clearly have the other pair beat, solely because of the more closed-off-design of the grills, leading to a more intimate and warmer/less airy sound signature.
For things like orchestra, soundtracks, movies and gaming however, I might have to recommend the HD565.
Both are surprisingly high quality cans which at the moment I actually prefer to my HD595 and yes, even the DT880 (black 250ohm edition). It kinda makes me think about selling those... but I guess only time will tell...
Oh, another nice thing about these cans: they can be had for dirt cheap prices these days (I paid about 60 euro for each) and most all things from cables to earpads are replaceable with HD580/600/650 parts (look for the HD565 appreciation thread here on headfi for more info)
Anyway, back to enjoying music I go. Cheers!