[i2ehan]

Quote:

Do you still have your fr graph there? Even though it's not some massive defect it makes me wonder how that reversed ear got through the QC. Its curve on the fr graph should be significantly uncorrelated with the other ear, which I assume to have been correctly wired.

Apparently not:
 

 

[Mython]

If a stereo pair of transducers are operating out of phase with one another, the characteristic effect is generally one whereby the 'width' of the soundstage appears 'strangely' 'widened', and the imaging generally goes severely out of focus. It can be quite unpleasant for the listener, at times, as the brain is trying to make sense of something it knows sounds unnatural. Owing to the fact that, when out of phase with one another, one transducer will be 'pulling' air whilst the other is 'pushing', it is unsurprising that a degree of perceived 'cancellation' may occur in parts of the bass response, thus potentially reducing the perceived quantity of bass. This kind of phase-varying effect was deliberately implemented in a lot of mass-market lo-fi 'midi systems' during the late 80s and early 90s, in the form of a variable potentiometer knob, adjacent to the bass and treble controls, which would vary the phase between the left and right loudspeakers between 0 and 180 degrees. Very lame, but popular, for a time, with 'the great unwashed'  

  Of course, with a pair of IEMs, perceived 'cancellation' of certain bass frequencies would not be expected to occur to anything like the same extent, if at all, but the human brain is vastly complex so it may yet perceive something along those lines, regardless. In any case, the other strange-sounding characteristics of phase manipulation still tend to be perceived in much the same manner as with fullsize loudspeakers.
 
 
As a brief aside, much as I love my Cowon J3, I've long had a lingering suspicion that the BBE+ '3D Surround' setting may be little more than a phase manipulation strategy. If I'm off the mark with that, then great, but it sounds to me suspiciously like a phase manipulation effect of some sort.
 
 
 
Frankly, for several Merlin/Miracle customers to be reporting this issue is rather alarming, from a quality control standpoint. It doesn't exactly instill one with much confidence that the multiple drivers within the acrylic shells have been wired properly in-phase with one another, does it? (and I'm saying this as someone who's still awaiting delivery of a pair of Miracles). Br777, you may recall me discussing the possibility of phase issues when you first received your Miracles, and my suggestions in that thread were mostly met, by fellow Head-Fiers, with the sound of tumbleweed blowing through a desert  

 

[Mython]

Quote:

Originally Posted by tranhieu /img/forum/go_quote.gif
 
 
Do you still have your fr graph there? Even though it's not some massive defect it makes me wonder how that reversed ear got through the QC. Its curve on the fr graph should be significantly uncorrelated with the other ear, which I assume to have been correctly wired.

If the entire 6 drivers are collectively wired out of phase in one IEM vs those in the other IEM, then I wouldn't anticipate that being in the slightest bit apparent on the printed frequency response charts.
 
However, if only 1 or 2 BA drivers were out of phase within an IEM then that might be more apparent on freq response charts, although even then, it'd depend to some degree on whether pairs of drivers were out of phase with other pairs (in which case, it seems plausible to me that one might, perhaps, expect a 'dip' to occur at crossover frequencies where out-of-phase pairs overlap with each others output).
 
If it was just a single BA driver in an IEM that was wired out of phase with the other 5 BAs (or less, in the case of the Merlin), then I'd expect that to be more clearly apparent on the frequency response chart, with an obvious decrease in output across the broader spectrum of that particular driver's output, owing to it, and it's companion BA operating at the same frequency, significantly 'canceling-out' each others output.

 

[tranhieu]

Quote:

Quote:

Apparently not:
 

That's some nice graph you have there! I reckon those people in the lab measured your custom before the socket was glued into the shell.
 

 
Quote:

If a stereo pair of transducers are operating out of phase with one another, the characteristic effect is generally one whereby the 'width' of the soundstage appears 'strangely' 'widened', and the imaging generally goes severely out of focus. It can be quite unpleasant for the listener, at times, as the brain is trying to make sense of something it knows sounds unnatural. Owing to the fact that, when out of phase with one another, one transducer will be 'pulling' air whilst the other is 'pushing', it is unsurprising that a degree of perceived 'cancellation' may occur in parts of the bass response, thus potentially reducing the perceived quantity of bass. This kind of phase-varying effect was deliberately implemented in a lot of mass-market lo-fi 'midi systems' during the late 80s and early 90s, in the form of a variable potentiometer knob, adjacent to the bass and treble controls, which would vary the phase between the left and right loudspeakers between 0 and 180 degrees. Very lame, but popular, for a time, with 'the great unwashed'  

  Of course, with a pair of IEMs, perceived 'cancellation' of certain bass frequencies would not be expected to occur to anything like the same extent, if at all, but the human brain is vastly complex so it may yet perceive something along those lines, regardless. In any case, the other strange-sounding characteristics of phase manipulation still tend to be perceived in much the same manner as with fullsize loudspeakers.

Do you have any papers that discuss about being out of phase leading to changes in terms of bass response? I thought it was nothing but the delay with regard to sound perception?
 
 

 

[i2ehan]

Quote:

Frankly, for several Merlin/Miracle customers to be reporting this issue is rather alarming, from a quality control standpoint. It doesn't exactly instill one with much confidence that the multiple drivers within the acrylic shells have been wired properly in-phase with one another, does it?

My exact concern as well.
 
Quote:

That's some nice graph you have there!

Sounds even nicer than it graphs! 

 

[Br777]

well, the graph notes are in chinese.. for all we know that is a stock graph, and all the little notes are indicating how much in line the measurements are with it... probably not the case, but just sayin, I cant read chinese.

 

[Mython]

Quote:

 
Do you have any papers that discuss about being out of phase leading to changes in terms of bass response? I thought it was nothing but the delay with regard to sound perception?
 
 

"Perceived"
 

 

[Kanashimu]

So I wanted to try that and then I notice something incredibly weird..
 
 

 

 
 
This is not good. Not good at all.

 

[tranhieu]

Is that a crack on the left ear's socket?

 

[Kanashimu]

Actually the issue is that the gold plating on the right earpiece is gone.

 

[tranhieu]

shoot UM an email then. that's one thing I don't like about recessed socket, you cannot unplug your cable at will.

 

[Kanashimu]

Wow, I just had an epiphany. I've been listening to the Miracle at too low of a volume level all this time. I don't know about you guys, but the Miracle doesn't have the best low volume performance to me. After turning it up to medium-high, it is practically perfection. It sounded rather cold and lifeless before, without dynamics, the midrange without lushness in female vocals.. and its all just perfect now.

I am so impressed.

 

[hardtarget666]

Sigh....it would be a month before I get my refitted Miracles back.  All this wait has made me almost disinterested in the whole thing and the lack of communication from Ampcity UK is further aggravating the whole thing. Has anyone heard about the silver cables from the promo? I got a email a few weeks back saying it would be another 2 weeks before we get it and nothing so far.
 
This probably will be the last time I order anything from Ampcity or Unique Melody.

 

[deadkenny64]

Since you are in the UK I don't know what kind of options you have but I can say nothing but good things about the US experience.  Stephen replied to all of my emails within 24 hours and updated me regularly.  I'm not sure if UM is overloaded now but I ordered mine in Nov and had them in exactly 5 weeks.  I certainly do feel for you as nothing frustrates me more than no feedback.  Did you try contacting anyone on the UM Global site?  I'm not sure what they could do but they are also very responsive and might be able to push your order along.

 

[dazzleng]

On friday while leaving melb to Warrnambool for a working weekend and I get an email from UM Aus that my Miracles just arrived so a minor detour to the head office to pick them up! So had them running pretty much throughout the whole weekend, burn-in should be just about done I reckon!
 
I did listen to them off and on over the weekend and it's pretty interesting as both the Miracles and cables were burning in and would have slightly different characteristics during the burn-in period; more pronounced bass, then treble got more controlled with the bass becoming punchier, etc.
 
Here are some pics with some side-by-side comparo with the Shure E4c reshells:
 
(apologies for the dustiness!)