Grado GR10 part2: General analysis [UPDATED]

Big thanks goes to Goodvibes, who kindly refurbished the defective GR10 for us. This analysis is due to the collective effort gathered from many users, and I truly appreciate their support. You guys rock!

[UPDATED on 09/08/2012] Acoustic leak issue has been resolved.


According to Yashima Electronics Inc., the manufacturer of GR10's transducer units, compared to conventional bi-pole balanced armature drivers, which are manufactured mainly by Knowles and Sonion, their single-pole balanced armature drivers are more efficient in converting electric signal into sound due to its piston-like simplistic design similar to that of a dynamic transducer, while still maintaining  linearity under the ear canal impedance due to its high acoustic output impedance(low compliance). Most of all, single-pole drivers are cheaper to mass-produce!

At the end of the article, Yashima deliberately compare a dynamic type(black graph) to their single-pole balanced armature type(red graph) to show off their superior technology.

However, the dynamic one seems to be performing much more accurately in accordance with the human HRTF than the single-pole driver does- I guess Yashima really doesn't care about the HRTF compensation after all.

PRO: As expected, this pair performs much more linearly than the previous one. The harmonic distortion is just far lower. Filters are interchangeable. Light-weighted. Fortunately, GR10's driver performs much closer to the human HRTF than what Yashima Electronics claim.

CON: Again, the high frequency extension is still lacking. Due to a silly manufacturing error, the polarity of both channels has been inverted. Since this was not of an issue with the previous pair, it must be a simple soldering mistake done by the manufacturer, and either Grado or Yashima Electronics must be blamed.

ON SECOND THOUGHT #1: By connecting a 100-ohm resistor in series to the IEM, the trasducer gets underdamped as shown on the right, and the output follows its own input impedance. (+12.5 dB @ 20 kHz) Consequently, as the high frequency extends, the sound becomes brighter and peaky. The high frequency can be boosted up to 17 dB @ 20 kHz with a resistor value of 480 Ω. Moreover, due to the mechanical resonance @ 2.4 kHz, the sound pressure level around that region will also be boosted.

ON SECOND THOUGHT #2: Plots on the right demonstrate the frequency response deviation caused by various insertion depths. The less inserted, the more mid-frequency peak it will get.