RHA is a British firm that specializes in earphones, specifically in-ear monitors. According to its website, RHA stands for "true-to-life audio reproduction and lasting quality." The company recently released a brand new flagship model, the T20 ($239). The T20 looks very similar to RHA's previous flagship, the T10, but with what I consider to be some important and positive sonic improvements that make the T20 a more versatile earphone that will appeal to a wider audience than the rather bass-centric T10 did.
The RHA T20 is not the first in-ear monitor to allow for adjustability, but it is the only in-ear monitor currently in production that utilizes interchangeable filters to alter its frequency response. The T20 comes with three sets of screw-in filters (treble, reference, and bass), as well as a plethora of ear tips. Your fit options include six pairs of dual-density ear tips (two small, two medium, and two large), two pairs of double-flange tips (small and medium), and two pairs of memory-foam tips. The multicore, reinforced, oxygen-free copper cable is firmly attached with no provision for interchangeability, but all stress points are reinforced, especially on the jack end, where RHA uses a metal spring strain relief collar.
The T20 employs what RHA calls the DualCoil dynamic driver, which uses a second voice coil situated within its annular magnet. The two coils operate independently, dividing the frequency range, making the T20 a two-way driver system. This proprietary driver system is housed in a metal injection-molded stainless steel enclosure. Unlike many in-ears, which have sensitivity ratings of 100 or even 110 dB, the T20 is rated at 90 dB, placing it firmly into the medium sensitivity camp.
Like most in-ear monitors, the T20 is designed to provide good isolation from outside sound and complete isolation from your music for anyone nearby. Given the plethora of eartips that come standard with the T20, 99 percent of users will find one that fits them optimally. RHA's patent-pending moldable over-ear hooks made it easy to dress and adjust the T20's cables so that they fit comfortably around my ears and down my back or front.
As I mentioned, the cabling for the T20 is permanently attached; so, if the length of the cable isn't to your liking, you are stuck. I'd call it longer than needed for most portables, but it could wind up being shorter than you'd like if you plan for primarily desktop use. The cable itself is nicely flexible, and the built-in strain-reliefs should help it survive some fairly rough handling. If you do, by chance, damage the cable, RHA has a three-year comprehensive warranty on the T20.
I'm a big fan of memory-foam tips, so I was encouraged to find the two pairs that come standard with the T20. In practice, however, I found the foam tips to be my least favorite of all the included tips--they kept sliding off the T20's shafts. The small double flange and the medium silicon tips proved to be the best fits for my admittedly narrow ear canals.
I spent time listening to all three filters, and--surprise, surprise--they substantially altered the harmonic balance of the T20. I'm one of those old-fashioned audiophiles for whom neutral is always the best sonic path, so it should come as no surprise that I much preferred the "reference" filter to the "treble" and "bass" filters. It did the least damage to the native sound of the T20, which is exactly what I'd expect from a filter labeled "reference." With the reference filter installed, the T20 reminds me of the Etymotic ER-4 in its ability to get out of the music's way, but with a smidgen of extra midbass warmth. During longer listening sessions, I came to especially enjoy the T20's unfatiguing upper-frequency presentation. If you are into "sparkle," you might enjoy the treble filter's ability to spotlight the upper midrange and lower treble, but I found it offered too much of a good thing. With the reference filter in place, the T20's treble is perhaps slightly less extended than some might like, but I liked the its natural and un-hi-fi hyped presentation.
While the T20 doesn't focus on midrange detail quite as much as the aforementioned Etymotic ER-4, it still supplies adequate amounts of low-level information, due in large part to its silent background, unmarred by extraneous low-level hum or noise. The lower midrange merges smoothly into the T20's very present bass. I wrote present, but don't interpret that as overbearing or bass-centric. With the reference filter, I found the T20's bass was exceptionally well defined, with excellent spring-at-you-out-of-nowhere dynamics. I think for many auditioners the quality of the T20's bass will be its most memorable sonic attribute.
I used several headphone amplifiers and portable DACs with the T20, including the Aurender Flow, ifi Micro iDSD DAC 9, Sony NW-ZX2, Astell & Kern AK jr, Astell & Kern AK240, and Calyx M. In every case, the T20 could be driven to LOUD with lots of power left over. I was encouraged how well the new AK jr ($499) and T20 worked together, making a very cost-effective high-performance combo that weighs almost nothing--guaranteed to be a balm for the weary traveler.
• The T20 has first-class build quality.
• Screw-in filters deliver three different sound signatures.
• The T20's bass response is excellent.
• The T20 has a non-removable cable.
• The T20 lacks any control functions or microphone for smartphones.
• Only the reference filter provided anywhere near a flat response.
Comparison and Competition
Even within the narrow range of $200 to $250, you will find plenty of competition for the T20. The Shure SE315 ($248) also has good bass extension and a removable, replaceable cable. The MEElectronics A161P has greater treble extension than the T20, but it lacks the same level of bass control and refinement and has fewer fit options. These are but a few of the many options from companies including Sony, Westone, Ultimate Ears, HiFiMan, Audio Technica, Musical Fidelity, and Bose.
Most in-ear monitors have one harmonic signature. The T20, courtesy of its interchangeable filters, has three. Although my personal tastes strongly favored the "reference" filter, I'm suspect that the "treble" and "bass" filters will find some fans. While Amazon currently lists over 140 results for earphones between $200 and $250, none offer a greater number of included fit options or harmonic choices. Although the cable is not interchangeable, RHA's comprehensive three-year warranty should help assuage any fears about the T20's build quality.