For a company that has made its name developing headphones geared towards hearing protection, one of the last things you'd probably expect is to see their products featured on an audiophile review site. We were skeptical too, until we tried them.
Puro Sound Labs calls their $199 IEM500 "Studio Grade" monitors. You can add audiophile grade to that label too. Puro Sound shipped us a pair of the EIM-500 for review and we're mightily impressed.
There are three main features of the IEM500s design. The first is dual dynamic divers with a patent-pending phase-optimization. There is a custom 8mm woofer and 5.8mm titanium tweeter in each channel. The IEM500s are capable of 106 dB output. Puro Sound Labs says that the phase-optimized drivers are tuned to eliminate the increased mid-bass energy that is automatically generated in an in-ear monitor.
The IEM500s also feature Puro's Balanced Response Curve, which Puro says eliminates much of the frequency masking and distortion that makes listeners turn up the volume. Puro told me that the Balanced Response Curve has been influenced by research done by Harman International's Dr. Sean Olive, who is one of the pioneering researchers on headphones.
Finally, Puro has focused its attention on noise attenuation. The IEM500 cones with five different ear tips to help users find the perfect seal for their ear.
Lightweight and sturdy
The IEM500s are made of aluminum and high-grade plastic and are incredibly light but the knurled metal chassis gives them a solid feel. The knurled chassis serves a second purpose allowing you to get a good grip on the in-ear-monitors as you put them in your ear.
There is an inline microphone on the left ear cord. A single button handles all controls. Pressing the button once engages pause/play functionality. Pressing twice quickly will advance the song, and pressing three times quickly will go to the previous song. If you're on an iPhone, you can engage Siri by holding down the button.
There is nothing cheap-feeling about the IEM500s though the 3.5mm audio jack has a very thin barrel. If you're the type of person who likes to put your music player in your back pocket and sit down, I'd take care so you don't snap the tip.
I played the IEM500s primarily on the great-sounding $899 Questyle QP1R Digital Audio Player
with a number of high resolution FLAC, ALAC, and DSD files (if you're wondering about audible differences between FLAC and ALAC files, see our article here
). I also played the IEM500s on an iPhone playing standard AAC encoded music.
I want to emphasize clearly that the quality of the bass you'll get out of the IEM500s is directly related to the seal you get with the included ear-tips. Don't take the different sizes for granted. Getting the right size for your ear will yield spectacular results.
From the outset, I noticed that the IEM500 delivered incredibly clean, clear, and detailed sound. In fact, the higher quality the source, the more they shined.
Playing the 96kHz/24-bit ALAC version of "Sister Rosetta Goes Before Us" from Alison Karauss and Robert Plant's album, Raising Sand
showed off what the IEM500s are capable of. The recurring kick drum had weight and punch. Krauss' and Plant's vocals were spot-on. Nuances of Krauss' breaths between stanzas and her occasionally breathy vocals were beautifully, seductively textured. Those fine nuances and audible cues that you'd demand from any high end presentation were all there. Instruments were firmly placed along the soundstage in place and time.
On "Please Read the Letter" guitar strokes were nicely rendered with full body. Through the IEM500s, you could clearly make out Plant and Krauss individual vocals or relax your attention a bit to enjoy the harmony of their duet. In other words, the IEM500s easily allowed you to enjoy all the different layers and complexities that any song presented.
On the 96kHz/24-bit FLAC version of Elton John's "Tiny Dancer" I noted that the timbre and midrange were remarkably spot on. The presentation wasn't overly relaxed or overly forward. I felt as though the IEM500s were voiced to be extremely neutral without being sterile. In fact, I found their sound to be very smooth as exhibited by the 96kHz/24-bit FLAC version of Miles Davis "Blue in Green" from Kind of Blue