Intro/Explanation
Many cans need mods. Denon,Grado...etc etc , benefit from light to heavy handling by adventurous owners or professional modders. It's a tribute to the can's endearing qualities. It's enough to overlook and fix deficiencies and pay for it sometimes.
I have rec'd a sz pad switch be done which is a lvl1 mod that is the easiest and nets clear rewards yet some don't even try. If you're gonna be lazy you get what you are handed and nothing more.
- The Akai are the M-Audio
- They have excellent drivers
- They are robust aluminum and gunmetal construct
- They are bass blasters with a mod that can be done with (screwdriver,scissors, double sided tape...thick sticky type)
The Mod
After removing the pads (twist off) and 4 screws your looking at this:
I was sent a mail by someone who seemed to know these cans very soon after launch. They said 1-3 diaphragm vents can be opened. They said 2 would be the max before changing the remaining sig. They were right but they added the vents be opened consecutively. They were clearly wrong.
I was looking at these like a sub being ported/tuned. Total wrong perspective.
This mod (above) worked like a charm. Like the person said. But at high gain the diaphragm exhibited "wobbling" not quite to the point of distorting the sig but it was right there. Not good.
If a diaphragm is pulling in air from one side it is making a vacuum and the area closest to the openings will be pushed and pulled faster or slower than the opposing side.
If I closed the parts in the above pic marked X and left the rest open the driver will go nuts at high gain. Possibly tear itself up. That's the
basket. For all intensive purposes it's the same part of the driver that surrounds the back of a headphones dynamic driver (series of holes covered) That huge diaphragm needs to move air. The holes in the bottom of the Backing plate and pole piece are for cooling the motor/voicecoil pretty much. Not much to do with ventilation
On a dynamic headphone driver the dustcap is really just a bubble in the center of the molded diaphragm. It's not separate that I have noticed. The hole running up the back plate on a HP driver is actually able to let the diaphragm breathe (again...in a full sized driver it's more for cooling) but it's a super vac and causes a bloat. It's not too much air. It's just dead center effecting the back of the bubble dome faster than the edges of the diaphragm. That wrecks the sig.
After covering the other holes and opening just the back (before using common sense) this went right to bloat.
Pulling in much less air than 2 open vents but bloating?
It's not about the amount of air given to the diaphragm it's about where.
Started thinking about car audio at this stage after having opened these cans so many times and thought...If I gotta give them air
- The pole piece vent is hurting me and my goal. Not only did I reverse that mod I covered that with thick 2 sided tape. Pole closed
- If I try opening 2 holes on exact opposite sides and give the diaphragm some vent balance maybe I can amp higher before distortion characteristics.
- Bingo
That pole piece bothers the diaphragm and it needs to keep out particles (just cover it with thick tape or the like)
Open 2 holes directly across from each other.
It makes sense and it works. The diaphragm is being fed in a balanced manner. There is no vacuum from the pole piece.
This track
He's digging around in his pockets...chatting with the audience on a single mic. You can hear EVERYTHING. Pocket digging every harmonica note. This mod does not effect the sig. This took so long because not interfereing with these cans crystal clear response was the mission.
Mission accomplished.
Although I suppose several very-high-end headphones could be considered a lot.
