John Kolb wrote:
> The problem is that even when the published specs are correct,
> frequency response is seldom spec'ed. And when freq response
> is speced, often even 192 k sample rate cards are often spec'ed
> as 20Hz-20 kHz, leaving one to wonder if that's the only freq range that
> was tested, and it might perhaps respond up to half the sample
> rate, or does it have a fixed 20 kHz low pass filter, desirable
> with a 44.1 or 44 kHz sample rate but really limiting the possible
> response for a 96 or 192 K sample rate.
>
> The other problem is that most producers of commodity products for PC's
> don't want to offer tech support or even answer simple questions
> unless someone looks like a customer who will buy 1 million units
> a year.
>
> Buying and testing units until I find one suitable may get expensive :)
>
> John
>
>
>
> At 02:51 PM 11/1/2006, you wrote:
>
>> John Kolb wrote:
>>> Can one assume that any soundcard advertising 24 bit, 96 or 192 kB
>>> sample rate can output supersonic freqs rather than having a 20 kHz
>>> low pass filter rolloff on the in's and out's?
>>>
>>> John
>>>
>>> ---- <[email protected]> wrote:
>>>> --- In [email protected], John Kolb <[EMAIL PROTECTED]> wrote:
>>>>> Does anyone know of a USB soundcard that can output audio
>>>>> at freqs of at least 40 kHz (96 or 192 kB sample rate)?
>>>>> Only need single channel output, not stereo or 5.1,
>>>>> don't need audio input.
>>>>>
>>>>> John
>>>>>
>>>> There are many. The Audigy 2 NX is one of them, it is capable of
>>>> 24-bit 96kHz sampling and playback.
>>>>
>>>> 73 Alberto I2PHD
>>>>
>>>>
>> You can't assume anything with sound cards, most of the stuff you read
>> is marketing hype or outright lies.
>>
>> For example many cards advertise 96KHz sampling rate, but when you dig
>> you find that rate is for the digital port not the analog ports we use
>> with a SDR radio. Read, check, verify with sound cards or they will
>> steal your money.
>>
>> --
>>
>> Cecil
>> KD5NWA
>> www.qrpradio.com www.hpsdr.com
>>
The Delta-44 and Delta-66 are superb, but some of their other cards have
all kinds of funky increasing noise so at the edge of the band the noise
is 35dB to 40dB higher, and that is for a card that sells for $130,
totally bogus, the PreSonous Firebox has the problem you mentioned you
increase the sampling rate but the front end amplifiers are still stuck
at the same settings and it cost $300, totally bogus.
I mentioned in a recent post that the specs you often see for sound
cards is marketing hype or just plain lying.
--
Cecil
KD5NWA
www.qrpradio.com www.hpsdr.com
"Sacred Cows make the best Hamburger!" Don Seglio Batuna
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