Custom Cans HD600/HD650 mod: measurements and impressions

OK here we go, some foam versus measurements

Here's a zoom for a better look. Teal = Hollow foam, Red = #3 foam, Green = Solid Gray foam, Blue = Solid Blue foam


Hollow distortion


Solid Blue distortion is noticeably lower

Wait!!! WTF is going on above 10K? It took me a minute to figure it out, but... The first set of measurements were done with Modius E being fed from my 2013 Macbook Air via USB. Today's were done with my Yggrasil via Airplay through Pi2AES fed from my 2020 Macbook Pro. First of all, I moved the Modius E back to feeding my TV so I didn't have to get up and keep switching the Yggdrasil input back and forth between TV and audio systems, and I finally got REW to work properly with my MB Pro this morning...

I was like whatever, they will get the jist of the different foams, then I decided I should measure my HD800SDR. Same deal, massive drop off over 10K. I decided to feed the Yggdrasil via USB from the MB Pro, BINGO!!!

Guess which is Airplay and which is USB


Not only that, check out the difference in distortion



I had no idea Airplay gimped the signal so badly, WOW!!!

I'm also giving the #3 foam a go in the CC600

 

Interesting observation about AirPlay. I kinda wonder if it has anything to do with reducing Bluetooth noise on headsets

 

Looks like you're getting less spread in the bass response between hollow & solid blue than I got - he might have changed the foams since - but we're similar between hollow & 3.

Distortion's a bit tricky to judge because of the different SPLs, but the pattern of it is the interesting part to me: higher THD & H2 with bored (or no) foam, but higher H3 (especially vs H2) with more foam.

And it does it differently each time!

 

Your measurements are from the HD6XX correct? I’m wondering if the difference in drivers is the culprit rather than the foam. My measurement rig is shoddy at best, but fairly consistent.

I’m liking the #3’s and dont really care for the blue foam, way too lean.

 

The Airplay system is picking up or transferring quite a bit more power supply noise vs the USB system: 30 & 60 Hz spikes in H2 with 20 & 40 Hz spikes in H3 => 60 & 120 Hz noise in the signal.

Way less impressive spikes than mine though 'cause my measuring space is right above this:



Edit: Hmm, evidently I'm crap at recording AV with my phone. Here's one showing the ambient noise with my measurement mic in its usual position:

 

He's offering it for free and allowing people to mod the design on thingverse. Why you so sour? If he was trying to charge for it that's another story.