Signal / Noise ratio

[BJG718]

Are the higher signal to noise ratios better? eg: Is there less noise with a 95db signal to noise ratio versus 120 db? Or is it the other way around. I always thought it was the higher, the better?

 

[BJG718]

srry - I mean ratio, not ration

 

[MDS]

The higher the better. It's not so much that there is less noise but that you can hear the noise less.

All electronics have some level of noise even with nothing connected and the volume at a low level. This is the 'noise floor'. The S/N ratio, as its name implies, is the ratio of signal to noise; so 90 dB S/N ratio means that the signal is 90 dB above the noise floor and that is pretty damn good.

 

[BJG718]

90 db is better than 120 db then? I thought that with 120 db signal/noise there would be more signal than noise, which would be better?

 

[jaxvon]

As said before, higher is better. So 120dB is better than 90dB.

 

[Porcupine]

> All electronics have some level of noise *even with nothing connected and the volume at a low level*. This is the 'noise floor'.

Ah. This is exactly the answer to the question I asked in another thread, thanks.

> The S/N ratio, as its name implies, is the ratio of signal to noise; so 90 dB S/N ratio means that the signal is 90 dB above the noise floor and that is pretty damn good.

90 dB above the noise floor at what volume setting? Because at minimum volume setting the signal will be at the same level as the noise, right? That's what I experience with my current setup. At minimum volume, I can hear slight noise coming from my tweeter if I press my ear to it. I can also hear slight music about the same loudness if I press my ear to the tweeter. As I turn the volume up, the music gets louder but this particular noise stays the same (other types of noise will get louder but those come from other components). At what volume setting does the music get to be 90 dB above the noise floor? Maybe the rated (max) power?

 

[MDS]

The s/n ratio is not dependent on volume; it is relative to some known reference level when the measurement was taken. My Onkyo receiver simply says 100 dB (IHF-A). The IHF is the rating method and A is A weighted. It does not say what the reference is, but given that the S/N is so high, I would assume the reference is 1 watt.

Here is a link that explains it fairly well: http://www.bcae1.com/sig2nois.htm

 

[Porcupine]

> It does not say what the reference is, but given that the S/N is so high, I would assume the reference is 1 watt.

Hmm. 100 dB S/N-ratio at 1 watt sounds good I think. 100 dB S/N-ratio at full power (100 watts for my Onkyo receiver) isn't as good I think. That'd be around equivalent to 80 dB S/N-ratio at 1 watt. Wonder which it is.