Quote:
Originally Posted by Pars /img/forum/go_quote.gif
Change the bandwidth or input impedance or both and the possible SNR will vary accordingly.
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ALMOST RIGHT,
I was waiting for this, guys. ( yes old teacher !!).
The figures given by the online calculator used by one of you ( sorry i don't remember who ) are good for theoretic telecommunications and considering a wide band amplifier without any filtering. ( a band-with filter increase
the level )
On audio test performing you must filter the band ( there are some buttons on the Audio Test Set to do it accordingly to the IEEE and other standards !!!)
We used a 20Khz band-with, that is a standard. Other use a "A weighted" filter and so on ( not bad if you think that humans have not yet decided if measure distance in km or miles...or naval miles ..)
Other standards and related filters are used for telecommunication, voice, or data.
Headphone applied at the output of the amplifier, can be considered as a filter ( as well as human hear for some other aspects ) and measures in order to be something real ( and not only theoretic numbers) must be done in accordance to it.
Since we do not design figures but real amplifiers, we make our measures assuming as output is used an headphone and not an online calculator.
BTW
We are not interested in impress people with numbers, but with sound.
Rudi Stor
RudiStor Sound Systems