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Discussion Starter #1
Can anyone please tell me what the difference in these numbers would indicate? Or what it all means?


Test Subject 1.


DOLBY DIGITAL PERFORMANCE

Output at clipping (1 kHz into 8/4 ohms)

1 channel driven: 151/224 watts* (21.8/23.5 dBW)*

5 channels driven (8 ohms): 56 watts (17.5 dBW)

6 channels driven (8 ohms): 53 watts (17.2 dBW)

Distortion at 1 watt (THD+N, 1 kHz)

8/4 ohms: 0.03/0.04%

Noise level (A-weighted): -76.3 dB

Excess noise (with sine tone)

16-bit (EN16): 0.9 dB

Frequency response: 20 Hz to 20 kHz +0, -0.15 dB


STEREO PERFORMANCE, DIGITAL INPUT


Reference level is -20 dBFS; all level trims at zero. Volume setting for reference level was -3 dB.


Output at clipping (1 kHz, 8/4 ohms, both channels driven): 99/137 watts* (20/21.4 dBW)*

Distortion at reference level: 0.03%

Linearity error (at -90 dBFS): 1.3 dB

Noise level (A-weighted): -76 dB

with 96-kHz/24-bit signals: -84.3 dB

Excess noise (with/without sine tone)

16-bit (EN16): 0.8/0.25 dB

quasi-20-bit (EN20): 12.2/11.7 dB

Noise modulation: 1.3 dB

Frequency response: 20 Hz to 20 kHz +0, -0.1 dB

with 96-kHz/24-bit signals: 20 Hz to 43 kHz +0, -3 dB


Test Subject 2



Output at clipping (1 kHz into 8/4 ohms)

1 channel driven: 144/217 W (21.6/23.4 dBW)

5 channels driven (8 ohms): 85 W* (19.3 dBW)*

7 channels driven (8 ohms): 80 W* (19 dBW)*

Distortion at 1 watt (THD+N, 1 kHz)

8/4 ohms: 0.02/0.03%

Noise level (A-wtd): -77.9 dB

Excess noise (with sine tone)

16-bit (EN16): 1 dB

Frequency response: 20 Hz to 20 kHz +0, -0.0 dB


STEREO PERFORMANCE, DIGITAL INPUT

Reference level is -20 dBFS; all level trims at zero. Volume setting for reference level was 78.


Output at clipping (1 kHz, 8/4 ohms, both channels driven): 124/175 W (20.9/22.4 dBW)

Distortion at reference level: 0.02%

Linearity error (at -90 dBFS): 0.0 dB

Noise level (A-wtd): -75.9 dB

with 96-kHz/24-bit signals: -87.7 dB

Excess noise (with/without sine tone)

16-bit (EN16): 0.8/0.8 dB

quasi-20-bit (EN20): 10.7/11.5 dB

Noise modulation: 1.2 dB

Frequency response:
 

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Near as I can tell, Test subject 2 is a more powerful amp. Other than that, I don't pay much attention to specs.


Noise levels look comparable. Distortion look comparable, but they don't specify what kind of distortion (usually it's THD + Noise)


Borrow a copy of the Sound Reinforcement Handbook from a library or buy one, and it covers a lot of those specs. And/or google amplifier specs for a detailed explanation of what all that means.
 

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Quote:
Originally Posted by MichaelJHuman /forum/post/14282669


Near as I can tell, Test subject 2 is a more powerful amp. Other than that, I don't pay much attention to specs.


Noise levels look comparable. Distortion look comparable, but they don't specify what kind of distortion (usually it's THD + Noise)


Borrow a copy of the Sound Reinforcement Handbook from a library or buy one, and it covers a lot of those specs. And/or google amplifier specs for a detailed explanation of what all that means.

Thanks. Those were test bench comparisons from sound and vision Mag for the Onkyo SR 605 and the Yamaha RX-V661. Test Subject #1 was the yamaha and Test Subject #2 was the Onkyo. Both are 90WPC receivers. So it would appear that the Onkyo produces more power per channel when all channels are driven?
 

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#1 appears to have 6 channels and #2 appears to have 7 channels. Or is that a typo?


#2 appears to be slightly more powerful, but only enough more to make a slight audible difference. In a given room with the same speakers, if #1 is not powerful enough then #2 is probably also not powerful enough.


The other measurements are comparable.


Under most circumstances, in a 5.1 system, with all signal processing disengaged, I doubt there would be an audible difference between these two receivers. The Yamaha is supposedly a 7.1 receiver, so I don't get why it wouldn't be tested with 7 channels driven. Must be a typo.


When it comes to all this business of characterizing receivers as "warm" or "brittle" or whatever, I am a skeptic. I believe these sorts of differences can always be attributed to something other than the amplification stages of a receiver.
 

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Quote:
Originally Posted by dlenart25 /forum/post/14285001


Thanks. Those were test bench comparisons from sound and vision Mag for the Onkyo SR 605 and the Yamaha RX-V661. Test Subject #1 was the yamaha and Test Subject #2 was the Onkyo. Both are 90WPC receivers. So it would appear that the Onkyo produces more power per channel when all channels are driven?

From the numbers, it's clear that the Onkyo can supply more power continuously to all channels, however you should take that with a grain of salt. Rarely do you drive all channels simultaneously for extended periods at the same volume while watching a movie. Also the difference at 5 channels driven (85 W - 56 W) amounts to less than 3dB in output volume per channel.


I'm not saying that the Yamaha/Onkyo is better. I'm just pointing out that these numbers are not a good replacement for actually going into a store and playing with both units.
 

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Actually it tells you a bit more. Both units have a poor signal to noise ratio, though really about average for their price point. While anything over 90 might be considered excessive, anything below 80 is going to be audible. My personal experience is that S/N is cumulative, and thus over 90 is a good thing in its own right.


Distortion is very good, well below audible. Excessive noise is a little high, but reasonable for the price point. Frequency response is acceptable, not ideal, but implies that neither unit has an extended response on top beyond the audible range.


As for power, I think this would be more audible than you think. Those numbers mean that the Onkyo has a more robust power supply. It probably has a larger transformer and larger capacitors. What you see is that power dropped off pretty drastically when more than one channel is driven, and while all channels being driven is uncommon, three is not. The only time this will really be audible and problematic will be if the amp is being asked to drive loads requiring high current durring peaks, which this is not representative of. I mean, unless you like to listen with an average level in excess of 100db's, then its unlikely the amp could not deliver the goods. However, I would not pair the Yamaha up with a large 4ohm complex load, as even during typical peaks the amp may struggle to deliver the necessary current and shut down. The only other area it might be audible would be in a highly dynamic movie or music, or something recorded with very hot levels and near the limits of the amp anyway, you might find peaks to be more noticeably distorted.
 
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