Truthear: what they publish

This page does not review anything Truthear makes. It counts one thing: how much of what this database says about their products came out of their own documents, and how much had to be worked out or left blank.

Impedance is almost always printed. Sensitivity is the one that goes wrong, because a decibel figure means two very different things depending on whether it is per milliwatt or per volt — about five decibels apart at 300 Ω and eighteen at 16 Ω. The conversion is here.

• Converted from per volt — 8: the maker prints a figure per volt, converted here with dB/mW = dB/V − 10·log₁₀(1000/Z)

The hardest of the 8 to drive is the Truthear Zero:RED: 1.0 mW and 0.13 V for a 100 dB SPL peak. Their impedances run from 5.8 to 28 Ω, which matters because the voltage a headphone wants rises with impedance while the power falls.

280 of the 280 sources here reach 100 dB on all 8, and the cheapest of them is the Apple USB-C dongle (EU) at $9. “Reaches” means the maker’s own published power figure is enough at that load; it is not a judgement of how it sounds.

On hiss the count is smaller, because most of the industry does not publish a noise figure at all: of the 83 sources here that do, 77 stay under the threshold of hearing on all 8 of their in-ears. The one to watch is the Truthear PURE at 124 dB/V — the more sensitive the in-ear, the more of the amplifier’s own noise you hear.

Their lowest impedance is the Truthear Zero:2 at 5.8 Ω, so a source wants an output impedance at or below 0.72 Ω to satisfy the one-eighth rule on everything they make. 85 of the 169 sources that publish an output impedance manage that.

These counts use figures the source makers published themselves. A product that publishes nothing is not counted as a pass anywhere above, which is why the three numbers differ so much. The collection matcher runs the same arithmetic over whatever you actually own.

Power decides whether it gets loud enough, output impedance decides whether it tilts the response of a multi-driver in-ear, and the noise figure decides whether you hear hiss with sensitive ones. All three fit on one line of a spec sheet; most of the industry prints one of them.

Truthear publishes a power figure at a stated load on 1 of 1, output impedance on 0, a noise figure on 1. Of the 4 power figures this site displays for them at 32, 150, 300 and 600 Ω: 4 worked out by holding output voltage steady across loads.

Almost everything this site says about Truthear came from them. That is not the normal case and it is worth saying out loud.

The rule used here is the same for every maker and is described on the manufacturer index. Every figure behind it can be opened on the product page it came from, with the document it came from linked.

All 156 manufacturers · What the spec sheets actually say · Download the whole database