Any Audiophiles?

[wehitandrun]

I have a "signal to noise ratio" question...

Which would have better quality, "up to 97 dbdsignal to noise ratio", or "up to 98 db signal-to-noise ratio"?

I havent the slightest clue what either means... I just know that big time hi fi systems have similar qualities.

My New MP3 player has one, where-as the one I was drooling over has the other. I'm not sure which is actually better.

[ReadyToHearTheWorst]

... but which of them sounds better ?

[wehitandrun]

Yes, Exactly. Or just what the difference is, if there is one. It's only 1db, so I'd imagine it wouldnt be much.

[bambooneedle]

.........

[wehitandrun]

Thats the thing, I only own the 98db signal-to-noise ratio mp3 player.

I've been reading about how great "up to 97db signal to noise ratio" is for a certain other mp3 player, and I'm wondering if replacing the 97 with a 98 makes that much of a difference for what I have.

[bambooneedle]

It can't be that different, I imagine.

And you mean the 98 for the 97.

[wehitandrun]

And you mean the 98 for the 97.

That actually depends on how you read the sentence.

Sadly, there are no audiophiles on a musician's fan-board. =(

[martinfoyle]

Maybe this will help
http://www.netstumbler.org/archive/index.php/t-12391

-Signal strength/signal-noise-ratio question


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black02ep3
Hi,

I'm new at this, so please bear with me:

We are running sniffers in a room at various locations, trying to read signal strength/noise ratio at those spots at different times and trying to build up a simple pattern for the signal strengths.

We noticed that signal strengths are always varying by quite a bit at the some locations (variation being from 5 to 10 units). Is this normal? And if so, is there a way we can normalize the data so that they become more consistent? And how can we use the signal-noise-ratio alongside the signal strength? (currently we're disregarding the signal-noise-ratio values)

Thank you very much,

James

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Thorn
Hi,

I'm new at this, so please bear with me:

We are running sniffers in a room at various locations, trying to read signal strength/noise ratio at those spots at different times and trying to build up a simple pattern for the signal strengths.

We noticed that signal strengths are always varying by quite a bit at the some locations (variation being from 5 to 10 units). Is this normal? ...

Yes.

And if so, is there a way we can normalize the data so that they become more consistent?

Define "normalize" in this context.

And how can we use the signal-noise-ratio alongside the signal strength? (currently we're disregarding the signal-noise-ratio values)


Please rephrase the quesiton or define how would you like to use the SNR.

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black02ep3
"Normalize" as in, some sort of algorithm that will cause two sets of signal-strength and signal-noise-ratio to end up (nearly) the same

h(ss1, snr1)~=h(ss2, snr2)

In essense, if I get different signal-strengths at the same place, I want to have some way that tells me that even though they differ a little bit, they are really the same, through either the application of signal-noise-ratio or any other ideas.

As to "how" I want to use SNR, I really am not sure. That's the whole problem: it's there for a reason, I believe, so how do I use it? Use it as part of some calculation? Use it to determine whether to discard a signal-strength reading?

Thanks,

James

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Thorn
"Normalize" as in, some sort of algorithm that will cause two sets of signal-strength and signal-noise-ratio to end up (nearly) the same

h(ss1, snr1)~=h(ss2, snr2)

In essense, if I get different signal-strengths at the same place, I want to have some way that tells me that even though they differ a little bit, they are really the same, through either the application of signal-noise-ratio or any other ideas.

The mean Signal is probably the best then.

Signals (and Noise) always fluxuate to a certain extent, due to a number of different influences.


As to "how" I want to use SNR, I really am not sure. That's the whole problem: it's there for a reason, I believe, so how do I use it? Use it as part of some calculation? Use it to determine whether to discard a signal-strength reading?

S - N = SNR

Unless your a RF engineer, Ham, or some other "freq geek" it's probably not going to mean too much to you.

Typiclally you want a SNR to be about 10dBm or better to ensure a clear signal.

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Casisiempre
Typiclally you want a SNR to be about 10dBm or to ensure a clear signal.

You want it to be at least 10dBm, and generally, the bigger the SNR the better (if nothing else then less chance of interference cutting your signal).

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netzst
The operative word in SNR is 'ratio': there might be great SNR, but if the signal is so weak (low signal strength) that you can't hear it, it won't do you any good.

On the other hand, the signal could be quite strong, but if the noise is quite strong as well (low SNR), you won't be able to detect the signal out of the noise.

That's why both are reported.

Maybe.

Another way of looking at it might be, SNR tells how high the signal stands out above the noise. Higher SNR is better. But if the signal is weak, only expensive radio receivers are going to be able to detect it. High signal, high SNR, even cheap radios can pick it up. (Real high signal: even radios that don't want to hear it will hear it--but since they don't want to hear it, it'll go into THEIR SNR as 'noise'.)

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w2004
I am new in this field. Please bear with me.

Is it possible to increase the sampling rate for SNR to 100 samples/s in the NetStumbler?

Thanks for your comments.

W2004

[A rope leash]

I'm not an audiophile, or an RF engineer, but I deal with radio frequncies on a regular basis. Perhaps I can simplfy this.

"noise" is basically unmodulated radio frequencies. That means that the radio frequency does not have audio, video, or digital signal attached to it electronically. When the signal is gone from the television, we see "white noise". The SNR is basically a signal-strength measurement, compared to the natural "noise floor", which will fluctuate somewhat on its own.

Of course, 97 db SNL is better than 98, but one db ain't shit, and is barely detectable with very expensive equipment. I'm curious, though, as to what this means for the recieving equipment. 98 db is quite powerful, as your average cable system has about +30 at the pole, knocked down to about 5 at your television set. The more db you got, the more it can be split and distributed. +30 db at your TV will give you a "beaten" picture.

I assume that what this means for MP3 is the SNR of the output, that is the signal to the speakers, and if you are 98 db off the noise floor, then you are coming in very clear, that is, there will be very little "noise" detected by the ear, and with a digital signal, it should sound great.

It's a mystery, though, RF. This is a layman's explanation, simplified and possibly incomplete.

It's not sad that there are no audiophiles here on the Elvis Costello board. One cannot expect there to be. If one has a question regarding radio output, then one should ask that question where audio freaks hang out. We are all just Elvis Costello fans here, most of us anyway...so don't get all :=( about it.

Hey punk, did you see the 60 Minutes piece tonight about your generation? You guys are the corporate dream! They can't wait till you all get decent jobs! Keep buying crap and keep thinking it's a way of life. America needs you!

[A rope leash]

I don't know why I'm so hard on the young folks. I guess because my dad was so difficult.

Anyway, perhaps what the 97 db SNL is referring to on the MP3 is the amount of volume the system will handle before the sound becomes distorted from signal overload. In this instance, it would kinda be like the Spinal Tap guitarist's amplifier which goes to "11". The difference between 97 db and 98 db is extremely insignificant.

But, one should never drool on any electronic consumer product. These things are very sensitive to moisture. Don't put it in your mouth, or eat it. Read the warnings...they are for "you".

[DrSpooky]

Another cynical person who is older than you.

Start with .. "don't buy anything you can't pay cash for." If you have to put it on a credit card, consumer credit loan, or "N days same as cash", walk away until you can afford it. Stuff-itis can really ruin your life.

When I was your age, I had a component stereo from a place in Nashville that built recording studios. It was great but frugally put together. I bought end of year and last year's models. I picked speakers on specs not on which rare wood was in the cabinet. I added a Nakamichi CD player as soon as it appeared the format would survive. I did pay cash for it all and it took a while.

The times they have changed. The cost of electronics has dropped and I have since learned that virtually no one has perfect hearing or an acousticly perfect room to listen in. Quality of speakers matters but the general quality of them has improved.

My advice .. don't buy the cheapest stuff out there but some nice mid-line gear. We recently got a nice sounding Panasonic packaged home-theatre system from Costco for about USD300. Buy something less expensive so you don't feel bad about replacing it when it breaks or some new format comes along.

FYI http://www.epinions.com and other sites are good for comparison reviews.

--DrSpooky

[A rope leash]

Hey Doctor...

Do you remember Quadrophonic?

My crazy brother is into this eBay cult that trades old Quadrophonic stuff from the '70s. He just bought 200 8-track tapes, about 10% of which are quad. He says all of the Elvis Costello 8-track catalogue is included. I assume this is everything up to about (hope-hope) Taking Liberties!

He actually takes the cartridges apart and rebuilds them. Believe it or not, it sounds pretty cool.

Quadrophonic was all the rage back then, but cassettes and CDs put an end to it. DTS is available now, but quite expensive.

My brother is now currently looking for a mid-'70s Lincoln, the only car made with 8-track Quadrophonic sound.

Nutty? Well, the music is what we grew up on, and the equipment is incredibly cheap. So why not?

[DrSpooky]

I remember quadrophonic although I am not quite old enough to have bought any. I do distinctly remember Bohemiam Rhapsody in my mother's LTD station wagon. Each voice came from a different corner of the vehicle. Very cool.

I also remember records becoming so thin that they were often warped before you played them the first time. Pops, scratches, and hisses that were frustrating. I still own a Discwasher D4.

WHAR .. you used to have to have a great turntable because each playing took a little life off the record. Electronics were expensive and lower technical specifications in general than all but the cheapest today. Expensive stereo components in that era did have a place. Given perfect surroundings,you might be able to hear a difference but in a normal house, I doubt it.

[Boy With A Problem]

Dr. Spooky wrote:

Start with .. "don't buy anything you can't pay cash for." If you have to put it on a credit card, consumer credit loan, or "N days same as cash", walk away until you can afford it. Stuff-itis can really ruin your life.

VERY GOOD ADVICE

[A rope leash]

I concur!

Thanks for the tip on the LTD wagon, Doctor. I'll pass it on to my brother. Was that a factory unit?