RP-500M II
speaker
$650
Used market: $470*
Specifications
4 of 4 values have a recorded sourceExpert Audio Engineering Commentary
Headroom Notes
92 dB at 2.83 V / 1 m is the highest sensitivity in this batch, and on an 8-ohm nominal it converts one-to-one to dB/W/m. The footnote is what to read carefully: the measurement is «half-space anechoic», which adds roughly 3 dB over a free-field figure, and the same footnote then calls the result «in-room sensitivity». A 10 W amplifier genuinely goes loud with these; it goes about 3 dB less loud than 92 dB would suggest when compared against a free-field number.
Amplification Warning
No minimum impedance anywhere on the spec sheet, and the nominal row does not give a nominal either — it reads «8 Ohms Compatible». For a horn-loaded two-way with a 1530 Hz crossover the impedance curve is usually benign, but that is inference, not documentation. Power handling is given as 75 W continuous / 300 W peak, which is the only load-related number the sheet actually commits to.
What the datasheet actually says
Quoted verbatim from the manufacturer’s own page, with the date we checked it. We state what is printed, not what anyone intended by it.
«NOMINAL IMPEDANCE 8 Ohms Compatible»
The row is headed «NOMINAL IMPEDANCE» but the value «8 Ohms Compatible» states which amplifier outputs may be used, not what load the speaker presents. No minimum impedance is published anywhere on the sheet, so the document contains no figure at all from which an amplifier's safe-load question can be answered. Wharfedale words the same row the same way — the phrasing is a habit of the category, not a one-off.
checked 8/5/2026«*SPL at 1M, half-space anechoic with 2.83V input, in-room sensitivity»
The footnote defining the 92 dB figure contradicts itself in six words: «half-space anechoic» is a laboratory condition — an anechoic chamber with the speaker flush in a boundary — while «in-room» is the opposite, a live room with reflections. Half-space adds about 3 dB over a free-field measurement, so this 92 dB is not comparable with a manufacturer who quotes free-field, and it is not a prediction of what the speaker does in your room either. When comparing against the KEF, B&W or DALI figures in this catalogue, allow for the boundary gain.
checked 8/5/2026* Estimated with the depreciation fallback (~72% retained value). · checked on 8/5/2026