New foam add-on for increased punchyness
Here's a little add-on to my HD-650 mod that I came up with yesterday. While giving it a test listen without the grills, I happened to place my finger over the open hole in the center of the driver, the one which is revealed after removing the 'spider' (shown in the center of
this photo). Upon completely closing this hole, I noticed a
drastic change in bass response. So then I experimented covering it with cotton pads then kleenex, but only to get an overtly muffled / bass shy result.
Next I tried 3mm low density foam sheets (
this one for 2 Euros each). This foam is such a low density that one layer literally makes no difference. But then I realised that the space between the driver and the grill should give just about a perfect distance to stack several layers of this stuff in, holding itself in place. So after several thickness attemps, I finally settled on 10 layers (a simple folding process outlined below).
The difference I noticed after multiple critical listening comparisons (
in mono with only one side modded at a time, switching the direction on my head to account for possible R/L hearing difference) was bass through mids that seem to have a faster attack / release - that is to say a bit punchier / more dynamic. If anything else, possibly a nuance of reduced mid-bass and treble - but as mentioned these were only changed the slightest of the slightest amount, if any at all. Overall I'm quite pleased with how similar this mod now sounds to the HD-600. It's like the bass off the 650 without the mid-bass bloat, the dynamics of the 600 and treble that may be somewhere between the two.... That is, in addition to my mod mentioned
here.
METHOD:
- Cut a rectangle of this low density foam, about 1x3" inches, then fold it in half the long way
- Fold it four times, so you get a total of 10 layers (I suck at math but somehow it added up to ten, LOL)
- Place the folded foam in the center of the HD-650 with the grill off
- With your finger still holding it in place attempt to replace the grill while keeping it in the center. Re-open slightly to nudge it into position if necessary, and it will stay in place
Finished product
Of course feel free to experiment with different types of foam, and granted there was already a foam cover on this headphone stock. But IMO, this is an improvement from the original.