The TRN-STM is a 1DD + 1BA earphone in the <$25 segment. It comes with three screw-on tuning filters (gold, red, blue) that appear to differ in length. At an impedance is 24 Ω and a sensitivity of 106 dB/mW, the TRN-STM is driven easily with any phone. My full review to follow.
Head-Fier since 2016. He has been known as “Otto Motor” to Head-Fiers, as “Dr. Schweinsgruber” to audiobudget.com users and Youtubers, and as “Brause” to Super Best Audio Friends and the Headphone Community. - For the purpose of confusion, he decided to pose under his real name Jürgen Kraus (“JK”) from now on. - This is a hobby. In “real” life, Jürgen is a professional geologist operating his own petroleum-exploration consulting company Franconia Geoscience Ltd. based in Calgary, Canada. He holds German and Canadian passports. Jürgen had a classical music education from childhood through high school in Germany and he has been following popular music developments since the late 1970s. His understanding of arts and crafts was influenced by Bauhaus pragmatism: “less is more” and “form follows function”.
Head-Fier since 2016. He has been known as “Otto Motor” to Head-Fiers, as “Dr. Schweinsgruber” to audiobudget.com users and Youtubers, and as “Brause” to Super Best Audio Friends and the Headphone Community. - For the purpose of confusion, he decided to pose under his real name Jürgen Kraus (“JK”) from now on. - This is a hobby. In “real” life, Jürgen is a professional geologist operating his own petroleum-exploration consulting company Franconia Geoscience Ltd. based in Calgary, Canada. He holds German and Canadian passports. Jürgen had a classical music education from childhood through high school in Germany and he has been following popular music developments since the late 1970s. His understanding of arts and crafts was influenced by Bauhaus pragmatism: “less is more” and “form follows function”.