Alright, I haven't heard anything about anyone else trying this. Really wanted feedback first but don't want to keep waiting. I gave that pair posted above to my friend for Christmas but he is coming from some random Logitech headset...he says it sounds good but doesn't really have comparison. So I'll post this with the hope that others try it.
I don't have the time to do any measurements yet. I can't say yet how these will measure. I've modded 3 pairs so far and they sound great...I am regularly picking them up and putting them on, but sadly this mod doesn't do anything for comfort. =)
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Here's my passive EQ mod for the 8323. It can be installed behind the driver or inline. The purpose is to attenuate bass and remove peaks in the 6-8k range to elevate the seriously lacking 3-5khz range, balance the sound, and reduce fatigue. The cans will be a little more forward and mid-oriented after the mod, but will still have solid (just not overdone) bass and should be less fatiguing. The can will work with far more types of music after the mod. Details in the upper mids and highs that were simply missing will be heard after the mod. It does change the sound signature so if you are a bass-head or like the 8323 sound, you may want to avoid (or use the less intense values, or buy two and mod one...).
This is what it looks like installed behind the driver:
Here's the schematic. There are also tables with different component values you can use to tune the circuit:
Here's the parts at Mouser. $10 shipped for one can, $15 for two. Also has spares in case you want to change some values.
https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=4b2e76698b
If you do this mod with the parts from Mouser, it may look a little different from the photo as I substituted two inductors for cheaper ones with higher resistance. They do little to nothing to the mod but do make the mod smaller and cheaper.
I can post the inline (non-permanent, plug-in box) parts list if anyone wants to do it that way. I don't like box dongles hanging off of my headphone cords and the cans are cheap enough so I just bought multiples and modded a couple. =)
By the way, they're still on sale for $20 and change at Monoprice.
Anyone willing to try this out and give me feedback?