Stealth Sonics: C9 Custom-Fit In-Ear Monitors

I've been in the music industry for several decades– and writing for Tape Op for a significant portion of that time. Along the way, I've met countless manufacturers, as well as their hired representatives, whose job is to connect the manufacturers with influencers and journalists like me. Earlier this year, Chandra Lynn (glowmarketing.com), a rep I've known for many years, reached out to me with an intriguing story about Stealth Sonics, a company offering innovative in-ear-monitor (IEM) designs that leverage extensive experience in medical, aerospace, acoustic, and music technologies. Chandra is someone I respect immensely, not only for her knowledge and sincerity, but also for her intention to seek and share balance in life. I immediately followed up, scheduling a meeting with Chandra and her client at the NAMM Show. What was originally planned as a 15-minute meeting turned into an hour of technical discussion, as well as a seating with an audiologist who took mold impressions of my ears. Soon afterwards, I received my own pair of customized Stealth Sonics C9 IEMs.

In short, the C9 sounds utterly fantastic. Listening to purchased music, my own mixes, and test tones– the C9 tops all audio reproduction systems that I have heard, for frequency and transient response. The lack of distortion is exemplary. Plus, imaging is convincingly three-dimensional; when I listen to LEDR (Listening Environment Diagnostic Recording) test files available on (audiocheck.net), I can clearly hear the sounds go up and down in height, as well as travel in an arc behind me. The phantom center is also unwaveringly strong.

How did the engineers at Stealth Sonics achieve such perfection? During my NAMM meeting, I was told that the company optimizes the aerodynamics of the internal pathways through which sound travels between the drivers to your ears, in order to eradicate airflow noise and resonance. In the case of the C9, there are eight tiny balanced-armature drivers and a single larger dynamic driver per ear, with three gently curved tunnels between the drivers and the rounded openings at the tip. The tip extends through the second bend of the ear canal, placing these openings just 2mm from the ear drum, which minimizes the acoustical effects of the ear cavity. Stealth Sonics has partnered with hundreds of audiologists throughout the world, who use a subminiature medical endoscope to peer into your ear canals, while making the mold impressions around the endoscope– ensuring an exact fit reaching just shy of your ear drum. The company offers a 30-day, no-cost refit if the delivered product isn't perfect. My C9 IEMs were immediately comfortable, and I can wear them for hours at a time without complaint. If anything, their fit is so precise that they're difficult to remove.

Stealth Sonics also perfected other critical aspects of their IEM design. For example, the double-twisted cord is strong enough to survive unintended pinching, but flexible enough that it can be routed or wrapped with ease– not unlike a rope for boating– without tangling. Importantly, the cord does not transmit any mechanical noise to your ears when it rubs against your clothing– an incredibly annoying problem that plagues IEMs from the more established manufacturers. The portion of the cord that loops over the top of the earlobe is covered in a soft silicone sleeve that is so comfortable– even though I wear eyeglasses– that I quickly forget about the cord hanging from my ears. The included carrying case is a semi-rigid, zippered box that is big enough to securely house the IEMs, three furnished adapters, and a cleaning tool, as well as a portable DAC of my choosing– without fear of these items being crushed in an overpacked bag.

Currently, Stealth Sonics offers three universal-fit and three custom-fit IEM models, ranging in price from $249 to $1,499. The fitted ones can be further personalized with a choice of outer plates as well as a custom engraving. And, it's fitting that someone who I admire for her success in finding balance in her life, and coaching others to do the same, introduced me to IEMs that offer the best balance of precision sound, comfort, durability, and overall ergonomics that I have experienced. If you are looking for IEMs that you can trust for accurate reproduction and long-term comfort– for enjoying music, and for recording and mixing too– I give the Stealth Sonics C9 my highest recommendation. I love my C9 so much that I subsequently purchased C2 and C4 models too.