[zest]

  Wow, this was pretty clever to get an idea where to block of the back area.
 

Yes, and the diameter is constant.

 

[LanceP11]

Are you referring to the whole album or just the one song called Break The System. How many hours do you burn in at a time?

The whole album is one song and is 44 minutes long. I usually loop it and burn in one hour intervals, then play it regular volume through my DAP for several hours, then back to the loop for another hour interval, and I'll do this for 24-72 hours, then it goes to 100 hours just listening through DAP.

 

[LanceP11]

HOLY SPIT!!! mochill, ericp10, and DaNuts were bullseye right on when they said the Zero Audio Doppio sound like a hybrid IEM. With aggressive burn in, changing from the Spiral Dot to the stock tips, and constant play, the low end driver "matured" and really opened up to a deep rich tone. They remind me of a more detailed reference Tenore, with more treble extension and less soundstage. Otherwise I'm having major trouble telling them apart. What a sweet, mid forward, liquid presentation. Very reference, but the bass is such where if you enjoy the Tenore bass, and enjoy that laid back accurate timbre sound, then the Doppio is a great IEM for you. A bit more expensive than the Tenore, but hey, the details and separation pop with these things. Also reminds me of my old Fostex TE-05's. I'm going to bed with a smile on my face.

 

[SkiesOfAzel]

  This sound plausible.  So, more foam means less room?  Or the positioning of the driver relative to the housing not being consistant.

 
I doubt that the factor is a variation in quantity, if quantity wasn't machined to be the same we would have gotten a lot of pairs with channel imbalance. If what causes variations is indeed the foam, the likeliest factor would probably be inconsistencies in its quality between batches. 
 
Completely blocking the vents has a relatively minimal effect on bass quantity though, so i have my doubts about the foam theory, but it's definitely worth checking out. 

 

[vwinter]

I doubt that the factor is a variation in quantity, if quantity wasn't machined to be the same we would have gotten a lot of pairs with channel imbalance. If what causes variations is indeed the foam, the likeliest factor would probably be inconsistencies in its quality between batches. 

Completely blocking the vents has a relatively minimal effect on bass quantity though, so i have my doubts about the foam theory, but it's definitely worth checking out. 

Channel imbalance, especially only a few dB in the low frequencies is generally harder for people to detect, which could account for that not being widely reported.

Besides, maybe they match up the amount of foam per set vs per earpiece which would preclude major channel imbalance issues. Just another possibility.

And completely blocking the vents may have little effect for those already in a low amplitude increase state for the subbass (ie "reference") because the foam may already be providing enough dampening to make more reduced airflow negligible.

Not saying these are valid but at the same time, just as possible.

 

[james444]

A few more pics. Poor quality, since I don't have a lightbox. And holding a flashlight in one hand while doing manual focus with the other is pretty challenging.
 
I didn't succeed in separating the cable sheath from the strain relief and pushing it to the inside (maybe the opening isn't wide enough). But I got a better look inside:
 

 
You can see the foam piece is actually pretty small and located between the cables:
 

 
Removing the foam exposes what seems to be some sort of back vent in the driver enclosure:
 

 

[vwinter]

Without opening up a less bassy set, it's hard to make this statement, but it appears that a bassy set has what could be a small amount of foam behind the driver. This makes sense, and may bode well for the varying foam theory... no?

Thanks James!

 

[shotgunshane]

  A few more pics. Poor quality, since I don't have a lightbox. And holding a flashlight in one hand while doing manual focus with the other is pretty challenging.
 
I didn't succeed in separating the cable sheath from the strain relief and pushing it to the inside (maybe the opening isn't wide enough). But I got a better look inside:
 
 
 
You can see the foam piece is actually pretty small and located between the cables:
 
 
 
Removing the foam exposes what seems to be some sort of back vent in the driver enclosure:
 
 

 
 
Back vent plate and front vent plate.  It's like a chastity belt to prevent dynamic driver mods.

 

[SilverEars]

Anybody know what the purpose of the foam is?  It's covering the vent I know, but why is it there?  What would happen if that is taken out and used?  

 

[SkiesOfAzel]

   
 
Back vent plate and front vent plate.  It's like a chastity belt to prevent dynamic driver mods.

 
James seems to be on the same page with Mel Brooks concerning chastity belts.
 

  Anybody know what the purpose of the foam is?  It's covering the vent I know, but why is it there?  What would happen if that is taken out and used?  

 
It's there to keep the small leprechaun that is singing in your ear from escaping. If you use it you may cause the expansion of the universe to revert itself. Caution is advised.

 

[luisdent]

A few more pics. Poor quality, since I don't have a lightbox. And holding a flashlight in one hand while doing manual focus with the other is pretty challenging.

I didn't succeed in separating the cable sheath from the strain relief and pushing it to the inside (maybe the opening isn't wide enough). But I got a better look inside:




You can see the foam piece is actually pretty small and located between the cables:




Removing the foam exposes what seems to be some sort of back vent in the driver enclosure:

How did you open these? Are they permanantely damaged or can you put them back together?

 

[vwinter]

Interesting, I do know for a fact that the foam behind the driver is there to reduce bass. Add more foam and I guarantee the bass is reduced even more. 

Yup, less volume in the back=less bass
less volume in the front=less treble

Rin demostrated this in his 9927 and MH1 mods.

Anybody know what the purpose of the foam is?  It's covering the vent I know, but why is it there?  What would happen if that is taken out and used?  

See quotes above yours.

I take it you're only skimming the thread.

 

[SilverEars]

See quotes above yours.

I take it you're only skimming the thread.

I read those quotes, wasn't entirely sure if the Tenore's setup was the same as the Sony as for the Tenore the vent is mention and the foam is covering the vent.  And this statement.
 

   
 
Back vent plate and front vent plate.  It's like a chastity belt to prevent dynamic driver mods.

 
If you look at Rin's sony.  He's just changing the back area. Not sure where foam comes into play.
 

 

[MuZo2]

If bass variation can be changed with foam mod but keeping rest of spectrum and matching the reference pair, it would be cool.

 

[luisdent]

  If bass variation can be changed with foam mod but keeping rest of spectrum and matching the reference pair, it would be cool.

 
That is essentially exactly what the mh1 mod does. By reducing the amount of air in the rear cavity the bass is reduced below a certain point without affecting the upper spectrum. I've modded a few mh1 recables I've done and they sound identical, but with less bass. SGS should be able to verify this with his set too.
 
The foam would essentially do the same thing by restricting the airflow and/or reducing air volume. Both having the same effect, but the foam probably to a lesser degree, unless it was thicker, more dense foam. Either way, it should control the bass to some degree without affecting treble.