SNR-what's the deal

2+2

Quick Q:
How important is signal-to-noise ratio for receivers/integrateds? My Marantz SR8400 has 105dB which I understand to be very good. I really like the sound of the SR8400 but to free up some funds, I am considering replacing it with Marantz PM7200 integrated cuz I only need 2 ch. THe PM7200 has SNR of 88db which seems really low (but has much better THD). Can someone briefly explain and opine as to whether this SNR difference will be noticeable and substantial? Any thoughts on this Marantz integrated? Another option is to get the HK3480 receiver which has SNR of 95 dB. Thanks.

2+2

Come on...somebody must know something here.....

Skynut

Patience young one, your answers will be revealed in due time.

I for one have not a clue what the answers are but I am watching to find out.

bknauss

SNR doesn't mean TOOOOOOO much unless its a really low number. I think once you're around the 80-90dB range, you're good to go and you won't hear the noise floor unless you're in a real good listening room. You're can't look at two receivers and make a decision based on SNR... and as always, if possible, the best thing to do is to listen to all of your options and let your ears decide.

2+2

Thanks bknauss....so SNR is associated with the noise floor and above 80db is pretty much good with increase above that providing progressively less improvement? Is that because it is measured on a logarithmic scale, the real life differences at the higher ranges is pretty trivial and small? (sorta like diminishing returns) Is that right?

Gaara

Last I checked this number didn't mean much for a few reasons. The first is you can have a very high SNR for your receiver, but if it is low on your source then it doesn't really matter. Also there will always be some background noise in a room, a fan going, wind, people talking in other rooms, transformers humming, which will generally be louder then the noise tagging along with the audio signal. There is also the fact that not all manufacturers measure this number the same, some will do A-weighting, some don't, some will use .5 Vrms, some will use more.

All in all if I remember correctly the magic number is 90, anything above that and you won't be able to tell the difference between a SNR of 95 or 115.

Jared

P.S. I don't believe to highly in THD numbers either many ways to manipulate this like negative feedback.

F1nut

More......

"Signal-to-noise ratio is an engineering term for the power ratio between a signal (meaningful information) and the background noise.

Because many signals have a very wide dynamic range, SNRs are usually expressed in terms of the logarithmic decibel scale. In decibels, the SNR is 20 times the base-10 logarithm of the amplitude ratio, or 10 times the logarithm of the power ratio where P is average power and A is RMS amplitude. Both signal and noise power are measured within the system bandwidth.

Signal-to-noise ratio is closely related to the concept of dynamic range, where dynamic range measures the ratio between noise and the greatest un-distorted signal on a channel. SNR measures the ratio between noise and an arbitrary signal on the channel, not necessarily the most powerful signal possible. Because of this, measuring signal-to-noise ratios requires the selection of a representative or reference signal. In audio engineering, this reference signal is usually a sine wave, sounding a tone, at a recognized and standardized magnitude, such as 1 kHz at 1.228 VRMS (+4 dBu).

Often the signals being compared are electromagnetic in nature, though it is also possible to apply the term to sound stimuli. Due to the definition of decibel, the SNR gives the same result independent of the type of signal which is evaluated (such as power, current, or voltage).

SNR is usually taken to indicate an average signal to noise ratio, as it is possible that (near) instantaneous signal to noise ratios will be considerably different. In general, higher signal to noise is better. (i.e. cleaner.)"

And.....

"A measurement of the range of signal levels the device is capable of. Dynamic range is the ratio (usually expressed in dB) between the noise floor of the device with no signal, and the maximum signal (usually a sine wave) that can be output without distortion. SNR, however, is the ratio between the noise floor and an arbitrary reference level. In "professional" equipment, this reference level is often +4 dBu, in "consumer-grade" equipment this level is −10 dBV. Different media exhibit different orders here — analogue cassette might give 60 dB, a CD almost 100. Nowadays most amplifiers have >110 dB dynamic range, which approaches that of the human ear, 160 dB."


Is your father ready to sell the Buckingham's yet?

2+2

Thanks Jared and Jesse...that was very helpful. I guess SNR is nothing to get worked up or concerned about.... which is good considering it is hard enough choosing different gear. Jared, you made a very good comment about the source!! Didn't even consider that into the equation...and what is the deal with all this non-standardized measurements and manipulation....what a mess.....

Jesse, I was in Cali. for the holidays and it doesnt look like those are going to move for a while....both of his Jamos are totally shot! Anyways, he is actually out here living with me now to help take care of my baby. The Mac and Tannoy are just sitting there!!

F1nut

Daniel, Congrats on the baby and Happy New Year!

Please tell your father I said hello and I'm still interested when he's ready.

2+2

Thanks Jesse...and will do....

SKsolutions

More than one way to measure a fish.