My favorite of the three is definitely the Periodic Audio Be (beryllium). I'm listening to it right now from the Chord Hugo 2 (pre-production unit), and it's an extremely impressive IEM for $299. During the CanJam SoCal video shoot, I didn't have time to listen to it for an extended period, but I'll keep it in my backpack to give it more listening time.
First impressions: I'd call the Periodic Audio Be's signature neutral-ish as I'd
personally define it (as "neutral" is still a bit of a moving target in the headphone world). There's flat-measuring like the Etymotic ER4SR, but that generally sounds (to me) leaner than what I'd subjectively call neutral. (For this reason, I prefer the Etymotic ER4
XR to the ER4SR.) My tastes have definitely shifted over the past few years to something more akin to the sound of flat-measuring speakers in a good room environment--something that compensates for the lost room effect with headphones.
(Though I've spoken with Dan Wiggins, we haven't specifically discussed
this topic yet. I'll hunt you down at CanJam, Dan!
)
Paul Barton of PSB has been discussing this for quite some time now. One day soon, I'll discuss a trip we took last year with Paul Barton to the NRC in Ottawa where we listened to the flagship PSB loudspeakers (that measure rather flat) in an anechoic environment (versus a more normal room environment). Anyway...
Here are the measurement from the CanJam SoCal Preview Video, where I compare the frequency response and total harmonic distortion of an IEM (Etymotic ER4SR) that measures pretty darn flat (with diffuse field correction applied) versus the Periodic Audio Be, which, in comparison, more closely meets my personal definition of
perceived neutrality.
(I will measure the Etymotic ER4XR and drop a similar comparison in here, sometime after I get back from CanJam SoCal.)
First, some information about the measurement setup I used for this--audio measurements were made using:
- G.R.A.S. 45BB-12 KEMAR with anthropometric pinnae for low-noise earphone and headphone testing
- This is a next-generation headphone testing setup, and you can read more about it by clicking here: Next Generation Headphone Testing
- I will be posting more details about this system soon, as it is definitely worth discussing in detail.
- Audio Precision APx555 Audio Analyzer
- Rupert Neve Designs RNHP headphone amplifier
- Herzan custom acoustic enclosure
NOTE: The measurements reflect diffuse field correction applied via the APx555's input EQ.
(Click on the images below to view them in a larger size.)