Falcon Acoustics Reference GC6500R Loudspeaker Lab Report

Lab Report

You'd expect a reflex-loaded speaker of this bulk to have high sensitivity but Falcon's claim of 91dB was not substantiated by our measurements. Our pink noise and music results of 88.3dB and 87.7dB at 1m for 2.83V input suggest that 88dB SPL is a more realistic figure. As is often in modern speakers, this is bought in part through low impedance. Falcon is more honest than some in claiming a 4ohm nominal but our measured minimum of 2.8ohm at 136Hz is a little low even for that specification. Impedance phase angles are large at low frequencies resulting in a challenging minimum EPDR of 1.2ohm at 96Hz, so the GC6500R needs partnering with an amplifier well capable of driving low impedances.

Forward frequency responses [Graph 1, below] were measured at 95cm mic height, with the grille removed. The responses are rather odd, with a pronounced switchback centred on 1.3kHz and treble peaking at around 20kHz. As a result response errors are on the high side for such a loudspeaker at ±3.9dB and ±4.9dB, respectively, while pair matching error is disappointing at ±2.0dB, principally due to narrowband tweeter disparities above 10kHz. Ribbon tweeters often measure poorly for distortion but the Reference's unit was especially high, recording 5.6% and 4.6% THD for 90dB SPL at 10kHz in the two speakers. Moreover, an odd modulation effect was heard at the start of the test tone with the first tweeter, and non-harmonic spuriae were seen in the distortion spectrum. Bass extension is a little disappointing at 56Hz (–6dB re. 200Hz), and the CSD waterfall [see Graph 2, below] shows high-Q tweeter resonances clustered around 9kHz. KH


Forward response shows a broad notch at 1.3kHz, a flat mid/presence and a peak at 20kHz


Cabinet modes are well damped but the ribbon tweeter shows breakup modes around 9kHz

Sensitivity (SPL/1m/2.83V – Mean/IEC/Music) 88.3dB / 88.3dB / 87.7dB
Impedance modulus: minimum & maximum (20Hz–20kHz) 2.8ohm @ 136Hz, 34.5ohm @ 53Hz
Impedance phase: minimum & maximum (20Hz–20kHz) –69° @ 65Hz. 47° @ 21Hz
Pair matching/Resp. error (200Hz–20kHz) ±2.0dB/ ±3.9dB/±4.9dB
LF/HF extension (–6dB ref 200Hz/10kHz) 56Hz / 29.1kHz/33.7kHz
THD 100Hz/1kHz/10kHz (for 90dB SPL/1m) 1.8% / 0.2% / 5.2%
Dimensions (HWD) / Weight (each) 1200x255x400mm / 65kg
Price £19,995

Falcon Acoustics Ltd
Supplied by: Karma-AV Ltd, York
01865 358001