🚀 go-pugleaf

"Trevor" <trevor@home> wrote:

>> SpectraLab showed a S/N ratio of over 97 dB with a 1Khz tone (not
>> 96.3).  You can see from the screengrab that it was taken in real
>> time, set to 16 bit with a 48Khz sample rate, used an appropriately
>> high resolution FFT window and Blackman analysis.
>>
>> You explain the error.
>
>SpectraLab is very good software, but it is not a certified, traceable,
>laboratory grade measurement system. And ANY measurement system has a degree
>of uncertainty. You just need to establish what it is. I can assure you both
>it is more than 1 dB.

I tried to find some guidance in the instructions about this, to no
avail.  I can believe what you're saying..

>> There's more!  SpectraLab indicates a S/N ratio of 100 dB with a 20Hz
>> tone.  See here :
>>
>> http://home.clara.net/media/sblive/20HZ-DO.gif
>>
>> You explain the error.
>
>The FFT window is too large for the signal, so more power is deemed signal,
>and less as noise.

Aaah.. I see!  So presumably this affects lower frequencies more, and
will more often than not result in an exaggerated S/N ratio reading?

>(yes I know that is it's maximum)

Actually can do 4x that.. this machine can't keep up!

>SpectraLab also mesures
>peak noise not RMS, not sure if any weighting is used.
>I would not be unhappy with those results though :-)

Quite!

>> I agree with this.. my basic problem with the site is that Kruger
>> doesn't keep it up to date and therefore these sorts of issues arise.
>> The same thing happened with my Echo Gina.  It *still* says "reference
>> card" on the test page which is incorrect, and the results are poorer
>> than I obtain with the card.  The same thing with my AWE64 Gold.  And
>> this is supposed to be a reference site?
>
>In Arny's defence, he isn't being paid to do this,

He claims it is a commercial venture actually.. I've even seen Mickey
Mouse being advertised on the site.  How appropriate, really.

>so I think the
>disclaimers apply. If you don't like it ...
>I think he admits the card may be capable of better performance, so can we
>all call a truce?

When people routinely take information from his site that may be
misleading as 'gospel', I don't feel any great urgency to drop the
matter.  Evidence is mounting that his tests of this 'range' of
soundcard is unreliable.  See him doing anything about it?


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