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Onkyo TX-NR609
Sound quality
Measured performance
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The TX-NR609 produced no less than 120Watts into 8 Ohms per channel under test, and even more into 4 Ohms – 210 Watts. It runs hot and the heatsinks inside are quite small so the receiver streams heat and a large but silent cooling fan beneath the top cover switches in to assist cooling we found during tests. However, there is no early thermal shut down unlike earlier models and the NR609 was able to cope with delivering high power for a long period under test.

Distortion levels were low, reaching a maximum of 0.025% at 10kHz, 1W output into 4 Ohms. The harmonic structure was extended odd order products our analysis shows and this is classic crossover distortion, so treble is likely to lack sweetness.

An analogue input signal through the A/D could not exceed 2.1V or overload occurred, a limit avoided by selecting Pure Audio. CD should be connected up digitally to avoid this limit. Whilst noise was low in this mode at -96dB, in spite of high input sensitivity of 180mV, it rose to -82dB through the input ADC. High input sensitivity allows the Onkyo to accommodate external low gain phono stages; there is no phono input. Frequency response was very wide, stretching from 1.5Hz up to 132kHz in Pure Audio mode.

Frequency response of the VHF/FM tuner was flat to 10kHz and very accurate. There is an mpx filter to remove pilot tone at 19kHz, introducing -65 rejection. Hiss was low at -70dB (IEC weighted) at full quieting and the TX-NR609 needed a modest 0.8mV (p.d.) from the aerial to achieve this. Measured IHF 50dB stereo sensitivity was good at 28uV so the tuner is sensitive all round.

Frequency response for CD through the D/A convertors  via the optical S/PDIF digital input was absolutely flat, reaching 21kHz (-1dB). Distortion was low too, measuring 0.22% at -60dB. With high resolution digital (24bit PCM) just 0.06% distortion was measured at -60dB. Bandwidth with 192kHz reached 55kHz our analysis shows, an good result. DSD code from SACD is recognised and converted to PCM, bandwidth reaching just 22kHz (-1dB), a poor result. SACD linearity at -60dB measured 0.22% distortion figure, much like CD.

The TX-NR609 measured very well in all areas, although performance with SACD was disappointing. It plays the DSD layer but with CD quality. The VHF tuner is a very good one, giving fine results all round. With PCM at 24/192 both bandwidth and linearity were good enough to reveal sound quality improvement over lower resolution codes. NK




Power      120W

Frequency response (Direct)    1.5Hz-132kHz

Separation   82dB

Noise (A/D, Direct)   -82/-96dB

Distortion    0.025%

Damping factor      21

CD / DVD 24/192 / SACD

Frequency response (-1dB)

2Hz-21, 55, 21kHz

Separation 88dB

Noise -102/106/107dB

Distortion (-60dB) 0.21, 0.06, 0.22%


Frequency response 20Hz-10kHz

Stereo separation 41dB

Distortion (50% mod.) 0.18%

Hiss (CCIR) -70dB

Signal for minimum hiss 0.6mV

Sensitivity (stereo) 28µV


BLU-RAY FREQUENCY RESPONSE, 24/192 PCM (what it means)



AMPLIFIER DISTORTION, 10kHz,1W  (what it means)


(Aux input, Direct, loudspeaker output)




(DSD code via HDMI input through to loudspeaker output)


VHF/FM FREQUENCY RESPONSE    (what it means)



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