[Saintkeat]

interesting hint. hah i don't think rebirthz is your dark horse right?
 
@ rebirthz and if you're a basshead then you're a basshead. ain't nothing to be ashamed about, and theres no such thing as reforming your musical preferences.

 

[Yikuso]

Just made my purchase and sent my ear molds out yesterday! Mine should be arriving by the end of May...hopefully.
@ rebirthz Thanks for the first impressions! Made me feel a little more confident about my investment. The problem you had with the bass is probably due to 

1. Dynamic driver needs some burn in time. The passive crossover also needs some (not sure, read from somewhere I can't remember).
2. The Merlin has a incredibly low impedance (despite its relatively high sensitivity). When it's driven directly from a portable player, it may suffer from the player's serial capacitor incorporated in its outputs. The serial capacitor is actually working as a high-pass filter which drops the bass off. These serial capacitors are often undersized on portable players due to cost/size, thus causing the bass to drop off much earlier on the frequency spectrum. Also, the lower the impedance, the earlier the bass drops off. These two factors together may lead to an audible decrease in bass. <--This might be the case theoretically. I too hope Project86 will have something conclusive in his review.
Cheers

 

[Somnambulist]

W00t. Looking forward to the reviews even more.  I would be amping mine if I got them anyway, so impedance wouldn't be a problem.

 

[project86]

Well, I got mine through Stephen at www.custom-iems.com - He just got confirmation that mine are in fact the earlier version.... they made a final tweak a few days after mine were made. Sounds like they were a bit conflicted about what they wanted it to sound like, but that's just speculation.
 
So now we are trying to figure out where to go from here. I am absolutely LOVING what I hear from my set, and frankly I'm not sure if I want a bass increase. But obviously there is no point in doing a review of a prototype product that is different from the final design. So we'll see.
 
And thanks for all the votes of confidence, but I believe there will be some other excellent reviewers popping up as well. I'm excited for others to hear these, even if they end up sounding slightly different.

 

[rebirthz]

@Yikuso: do you mean that since its a low impedance iem it benefits greater from amping? i was always under the impression that since its low impedance means its easier to drive, hence does not require an amp.
 
But yea have been playing them every night before i go to sleep to clock some burn in time, regardless i felt that these were worth every penny. But like project's merlins chances are mine arent the final versions either yet i already like what i hear.

 

[maverickronin]

Quote:

@Yikuso: do you mean that since its a low impedance iem it benefits greater from amping? i was always under the impression that since its low impedance means its easier to drive, hence does not require an amp.

BA IEMs usually benefit from good quality amp because of their silly impedance curves.  Those sorts of amps usually end up being way more powerful than you need but they don't have to be.  Some DAPs have decent quality amp built in to them while others don't.  The most important spec is the output impedance of the amplifier, and the lower the better.  Unfortunately almost no one specifies this which probably goes a long way towards explaining why IEMs are used with amps as much as they are.
 
There are a few other possible issues as well.  Some players have undersized coupling caps which can cause bass roll-off with low impedance 'phones.  The high input impedance of most any decent amplifier will give you back your bass in that situation.

 

[roy_jones]

Quote:

Well, I got mine through Stephen at www.custom-iems.com - He just got confirmation that mine are in fact the earlier version.... they made a final tweak a few days after mine were made. Sounds like they were a bit conflicted about what they wanted it to sound like, but that's just speculation.
 
So now we are trying to figure out where to go from here. I am absolutely LOVING what I hear from my set, and frankly I'm not sure if I want a bass increase. But obviously there is no point in doing a review of a prototype product that is different from the final design. So we'll see.
 
And thanks for all the votes of confidence, but I believe there will be some other excellent reviewers popping up as well. I'm excited for others to hear these, even if they end up sounding slightly different.

It's unusual that there would be so late a revision.  It kind of puts you in a weird position, having been sent a review sample and being a trusted reviewer, to give impressions of an IEM that isn't a production version. 
 
From an outsider's perspective it almost seems like UM is having something of an identity crisis.  Given that they've chosen to revamp the miracle with the intention of increasing their bass, and seem to have gone through a late revision that will likely do the same for the Merlin, it might be that they've relinquished the notion of having a "house sound" for a more broadly applicable sound signature that will be of interest to a larger demographic. 
 
I said from a very early stage, when the first reviews of the Mage were coming out, that they were making a mistake by going with a bass-lite house sound.
 
 
I'm most curious about whether the use of a dynamic driver will prove to have practical advantages or whether it will be seen as kinda gimmicky.    
 

 

[rebirthz]

personally having auditioned the universal miracles, i felt that using a dynamic driver manages to achieve one thing a BA usually has difficulty achieving, which is letting the users feel the bass. in the miracles i could hear them, but on the merlins i could literally feel the thump. but yes this is comparing the universal miracles and a custom merlin hence that may be an issue. look forward to project's feedback as i am still very new to this audiophile hobby =)

 

[kingice10]

I think UM has also the advantage of creating their top-custom iems...as they offer reshelling service on some universal/custom phones, they may have a general notion of what people mostly wants to hear from their customs. That's what I realized. What if they already have a database on how they will produce a certain-type of phone. Imagine the possibilities. And that's where as @roy_jones calls it identity crisis may come from and it's only me speculating.

 

[Anaxilus]

Quote:

I think UM has also the advantage of creating their top-custom iems...as they offer reshelling service on some universal/custom phones, they may have a general notion of what people mostly wants to hear from their customs. That's what I realized. What if they already have a database on how they will produce a certain-type of phone. Imagine the possibilities. And that's where as @roy_jones calls it identity crisis may come from and it's only me speculating.

This is true.  Doing a custom reshell or one-off project is a huge disadvantage for a company that doesn't make their own customs.  That's like asking a paint shop to build you a hot rod.
 

 

[Yikuso]

@ rebirthz Basically, if two phones have the same sensitivity, the one with lower impedance is harder to drive.
Say you have a source of 1.4Vrms output, two phones with 16 and 32ohms impedance. @1kHz, Current through the 16ohms one is 1.4/16=87.5mA, and 1.4/32=43.75mA for the 32ohms one. The power draw from the 16ohms one is then P=I^2*Z=0.0875^2*16=122.5mW, and 0.04375^2*32=61.25mW. You can see that the 16ohms phone is actually drawing more current and power from the source.
The reason why we think low impedance phones are easier to drive is that they usually comes with high sensitivity (>100 spl). It's just those low impedance and low sensitivity phones that are particularly hard to drive.
As for the Merlin, it should be relatively easy to drive. The coupling capacitor problem is always there, it happens on 32ohms phones too. It's just the Merlin's low impedance made it more audible. Like #157 said, anything with high input impedance(several k ohms) should bring back the bass. There's also problems like impedance matching and damping factor, in this case for amp output impedance, the smaller the batter (less than 0.5~1.5ohms). 
Hope this helps.

 

[rebirthz]

wow thanks that was highly informative. gotta do more research to fully digest it thanks! =)

 

[Saintkeat]

Miracles weren't a bassy iem to me. it was more neutral compared to the jh13. at least from what i heard from the universal.
 
Project86 please get the revision.. we'll wait... and you'll survive with the multitude of customs in your arsenal =D

 

[piotrus-g]

Quote:

@ rebirthz Basically, if two phones have the same sensitivity, the one with lower impedance is harder to drive.

Go back to page 5 where I wrote that it won't be easy to drive 12 Ohms. Well all I can say is: "told you"
Anyways thanks Yikuso for a pretty nice explanation
 

 

[FullCircle]

Quote:

I think UM has also the advantage of creating their top-custom iems...as they offer reshelling service on some universal/custom phones, they may have a general notion of what people mostly wants to hear from their customs. That's what I realized. What if they already have a database on how they will produce a certain-type of phone. Imagine the possibilities. And that's where as @roy_jones calls it identity crisis may come from and it's only me speculating.

 
Most IEM these days have proprietary numbers on them. This prevents other IEM companies from copying another IEM companies designs. Proprietary numbers also prevent employees from shareing information regarding product designs etc. In short, proprietary numbers protect a companies investment.
 
Because proprietary numbers are being used, I can open up a JH Audio product, and find out who made the driver, but I could not tell you what the specs are (such as impedance). Because of this, one can not easily copy a companies sound signature etc. Even the capacitors etc, being used by some of the IEM companies have no distinguishing marks.
 
My point is, I do not think that re-shelling is a key component of developing good IEMs.