mod: Monoporice 8323

[hans030390]

I was looking over the measurements for these on Innerfidelity, and they look like they have a lot of potential. They have a flat response down to at least 50Hz before they roll off, though this might not be an entirely accurate measurement due to the reports of these having quite a bit of bass. THD is fairly low. The 300Hz square wave is actually pretty good looking. Pretty clean looking with a bit of overshoot at the beginning. If I remember correctly, Tyll said that's generally positive.
 
They have a rather large dip between 2-7KHz and a peak around 7-10KHz, which I'm hoping I can improve with mods. I'm actually really excited to try these out!
 
What's strange, though, is how similarly these measured compared to my open-back modded D2000s (which ended up being an extremely ghetto mod due to changes I should have made, haha). Check out the FR response:
 
Monoprice 8323
Open-back D2000
 
The top end is where the main differences lie, but other than that...interesting.

 

[Armaegis]

To my ear, my mods basically flattened out the FR curve a bit. Even before mods the bass seemed stronger than the graphs indicate; I'd imagine they have a rather slow decay there which makes it feel more prominent. 

 

[hans030390]

Did some pretty basic modding on these. Lined the interior of the cups with Dynamat, threw sound Acousta-Stuf in there, and place a thin donut of a specific type of felt I have behind the driver (the part that circles the magnet in the middle). 
 
These are a steal at $20. With some basic modding...I'm speechless. They don't just sound great for their price. They just sound great all around!

 

[Armaegis]

You could also try putting some tape (regular or porous) over some of the magnet plate holes. This will decrease bass but should improve clarity a bit too. 

 

[hans030390]

Eh, I really like them where they're currently at.

 

[Roan3489]

Anyway you could put together a parts and tools list?
This is going to be my first mod and I'm also kind of new to the site, so I'm looking for as much help as I can get

 

[Armaegis]

Everything that I used:
 
spray rubber - roof sealer, from home depot (optional... and not recommended due to the mess)
dynamat - cheap substitute: blutack or poster putty
micropore tape - from walmart pharmacy section
acoustic foam - most easily found in computer noise/vibration damping kits or from speaker DIY shops
felt/velour/cotton/polyfill - raid your mom/grandma/gf's crafts closet, cotton for a buck from any pharmacy or hygiene section of a supermarket
 
The only tools needed are a small screwdriver and scissors. 
 
At the very very minimum for modding: just stick something soft and absorbent into the cup and see how that changes things. 

 

[CrystalT]

If I were to turn these in to open-backed headphones, how would one recommend approaching this?

 

[SanjiWatsuki]

Quote:

If I were to turn these in to open-backed headphones, how would one recommend approaching this?

I get the feeling this would turn out badly. The 8323 rolls off the bass pretty hard in the audible frequencies already, and making it fully open just seems like you would lose even more. 

 

[CrystalT]

...which would be the goal in the first place?

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[SanjiWatsuki]

Quote:

...which would be the goal in the first place?
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I'd just be worried about losing the sub-bass entirely. 

 

[CrystalT]

I don't care? I want suggestions on how to do it. Not what it will do.

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[Armaegis]

Quote:

If I were to turn these in to open-backed headphones, how would one recommend approaching this?

 
Well, the simplest way would be to just hack at the cups with a drill. Take a soldering iron and remove the driver/baffle first, tape the wire securely out of the way, then clamp that sucker down on a scrap piece of wood and drill some holes. A drill press would be ideal.
 
Fancier would be to cut out a large hole or the entire back of the cup and either leave it open or replace it with a mesh.

 

[CrystalT]

What type of mesh would one recommend, and what would they recommend to keep it in place.?

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[Armaegis]

Anything you feel like really... you can try and find various sorts at a hardware store, ot maybe cut up an old window screen, or grab something from the dollar store, etc. I've used dollar store garbage cans before, which are sort of a flexible plastic mesh. Keep it in place with glue, blutak, hot glue, or just simply pressure from the mesh itself on the walls of the cup.