Disclaimer: I thank the owner, UnityIsPower, for letting me analyze his precious gear. Measurement has been made with the bass-tuner set at its minimum.
Aurisonics ASG-2 is a hybrid IEM, featuring a dual-driver balanced armature tweeter and a ⌀15 mm dynamic woofer, just like T-PEOS H-200. Moreover, the IEM has an adjustable bass-tuner on its faceplate. According to eke2k6's review, this IEM doesn't have a passive crossover network implemented in order to avoid any kind of unnecessary complication arising from electric impedance interaction.
Now that's quite a bold move, considering the fact that three transducers are coupled together.. And since Mr. Dale Lott, the founder of Aurisonics, claims ASG-2 is tuned with their reference sound signature but treble further enhanced, the hope is higher than ever! But then again, one of my visitors says:
PRO: Sleek look.
CON: All the others including unstable impedance characteristic, unmatched woofer response, short bandwidth & non-linear frequency response. Moreover, unlike what the engineer has stated, there is no treble.
ON SECOND THOUGHT #1: The bass-tuner is very crudely designed; it does not restore the sub-bass at all. Rather, only the mid-high bass is amplified up to 15 dB, causing an audible ringing of the driver.
ON SECOND THOUGHT #2: Insertion depth plays a major role with this IEM, especially in the treble. Fortunately, shallow insertion yields less harshness.
ON SECOND THOUGHT #3: Due to its highly skewed impedance characteristic, ASG-2 is prone to electrical damping.
ON SECOND THOUGHT #4: Acoustic damping helps tame some of the peaks in the high frequency range.
ON SECOND THOUGHT #5: The vent located on the side of the housing works only as a depressurizer.
ON SECOND THOUGHT #6: Aurisonics ASG-2 is far far away from Harman's reference target. No, my friend. The sound quality of ASG-2 is not of a radio. It's rather of a telephone receiver.