GRADO GR10 part1: Aesthetics

Introduction

Finally, Goodvibes sent me back GRADO GR10, this time both units in function. And BIG THANKS go to the original owner, James444, and my friend, Inks. Since they are fully refurbished and feel like brand-new, I invested some time taking pictures.

Packaging

And the rest

Continued to part 2, the general analysis.

AKG K3003 part1: Aesthetics

Introduction

Aside from the fact that K3003 is AKG's very first balanced armature driven IEM, what else is K3003?

First, K3003 is a trailblazer; It is very first multiple transducer driven IEM without any added passive crossover network implemented.

Second, K3003 is a hybrid; While the mid-high frequency drivers are BA types, the woofer is a dynamic transducer.

Third, K3003 is a masterpiece; All of the non-electroacoustic parts are hand-crafted, and hand-assembled. Its degree of aestheticity in craftmanship is unparalleled.

Packaging

And the rest

Took quite long to take these pictures with my old Canon 300D.
Cut the crap- the pics speak for themselves.
No, AKG is not paying me for doing this, LOL 
And no, this unit is not mine!

Continued to Part 2, general analysis.
Continued to Part 3, In-depth analysis.

The effect of acoustic dampers on IEMs

I thank Knowles electronics for the support.

On most of balanced-armature transducer driven IEMs available in the market, there is a tiny screen implemented at the opening of the acoustic output port. This is an acoustic damper, and it serves two purposes:

1. The filter blocks off external materials from getting into the transducer, thus preventing damages to occur deriving from such causes.
2. The filter has an unique resistive value, and acts as a passive acoustic filter mainly reducing the first peak resulted by the mechanical resonance at f0. 

"The bump at 2 kHz is primarily caused by the mechanical resonance of the receiver: the mass of the diaphragm and springiness, or compliance, of the diaphragm combined wit the compliance of the air inside the receiver." H. Dillon, Hearing Aids, Boomerang Press, Turramurra, Australia, 2001. 

Their rated performances have been demonstrated by one of the manufacturers, but there has not been a single instance of which an actual IEM has been utilized. So Etymotic Research ER-4B is used to find out how the filters help shape the frequency response of an IEM.

With stock acoustic dampers:

With conventional acoustic dampers:

The first two peaks are definitely being controlled, and especially when the acoustic resistance reaches 2.2k ohm.  After this experiment, I changed the stock green filters (1.5 k ohms) on my ER-4B to orange ones, which are 3.3 k ohms. It's only flatter, with increased high-frequency bandwidth!

And here is the conclusive analysis of the experiment with ER-4, relative level differences plotted all at the same time. Click the graph, and it will get bigger.

Since the damper can turn ER-4B into ER-4S with broader frequency bandwidth, maybe vice versa, or even evolving ER-4P into other two might be possible without using an electrical filter. And that will be the topic of my next article, it seems!

P2B adapter for Etymotic Research ER-4P

As encouraged by the manufacturer, ER-4P can be easily turned into ER-4S, by simply adding a resistor in series. However, it has been proven quite tricky to turn ER-4P into ER-4B, since ER-4B has a dedicated high-pass filter(100 ohm resistor & 220 nF capacitor in parallel) implemented in its barrel.


Once again, my friend vAsurada, let me borrow his DIY-adapter made for ER-4P, a 3-way switchable passive filter which converts ER-4P into a ER-4S and ER-4B, simply by clicking a switch. He told me (with some doubt) that the accuracy is 99%! And I am pretty sure my regular visitor, Carrot, is the designer of the high-pass filter, but please correct me if I am mistaken.

As seen on the right, the adapter is a dual-layered PCB circuit, with a 3-way rocker switch attached. The switch first bypasses(4P), adds a resistance(4S), and finally adds a high-pass filter(4B) to 4P. The built quality is of top-notch, and I don't think you can get this quality from conventional manufacturers.

And here's the actual measurement of unfiltered ER-4, P&S&B superimposed together at 94 dB SPL @ 1 kHz. The data are very accurate, even by comparing them to the data provided by Mr. Don Wilson, the designer of ER-4. (different insertion depth in consideration)

4P to 4B accuracy is the sole target of interest, since 4P to 4S adapter is simply a resistor in addition. Its accuracy is rather insignificant.

And here is vAsurada's adapter:

Wow, the difference is less than 1 dB within 20~20,000 Hz! If you have this adapter in your possession along with ER-4P, it is same as owning 3 different IEMs at once, only for much lower price. I don't know about the percentage of 99%, but the adapter is damn accurate. I should return the adapter soon, and if you have any interest of purchasing one, ask vAsurada, not me. (no commercialism, please) Last time I asked him, the price was whooping 250 in USD! Anyway, it was a very fun experience, tinkering with this adapter. Thnx, vAsurada!

Introducing my 60318-4 occluded ear simulator

This is the 60318-4 occluded ear simulator I use for IEM measurements, with the conically-concaved proprietary external ear adapter attached. A pair of these are encapsulated in my dummy head, EURI, as well (level difference less than 1 dB from 20 to 20,000 Hz). Last time I got a quote from BSWA USA in April 2011, the price of this simulator was $3150 each.

Above is the calibration chart I received from the manufacturer, and the simulator has an acoustic input impedance effectively matching that of the human ear canal.

The effect of ear sleeves: The most comprehensive comparison yet with Phonak PFE-022

This is the result of yet another collective effort, and the final analysis of our first measurement phase. A lot of ear sleeves borrowed from various users have been used here. A credit goes to Inks, Joker, Anaxilus, and JupiterKnight! I really appreciate for providing such a generous opportunity, guys.

Phonak PFE-022 equipped with various thin calibered sleeves:

  

Silicone sleeves

Foam sleeves

Phonak PFE-022 & Monster ear sleeve adapter equipped with various thick calibered sleeves:

Silicone sleeves

Foam sleeves