TestGuru wrote:
Would a sound card based oscilloscope/spectrum analyzer/signal generator be a better choice for audio test & measurement? The reason is that a good sound card can provide 192kHz sampling rate, 24 bit ADC and DAC, very good SNR, THD, IMD....which is essential for HIFI testing.
booangler wrote:
I just finished reading Morgan Jones "Building Valve Amplifiers" and in it he states that Sound Cards should never be used as oscilloscopes. According to Jones (see page 191) the bandwidth provided by the sound cards are not nearly enough.
Yes, many sound cards have an analog bandwidth within 20Hz~20kHz, so it works within audio frequency only, and cannot measure DC, and will distort the square waveform in some degree depending on the square wave's frequency. Some good sound cards can work down to a few Hz, and up to 96kHz with a sampling rate of 192kHz and bit depth of 24. This should be enough for most, if not all, audio measurements.
IMO, for THD, SNR, IMD, Speech Intelligibility kinds of measurements in audio frequency range, a good sound card would be much better than a USB DSO with hundreds of Mega Hz sampling rate but has a bit depth of only 8 or 12. This is why the professional softwares (sold at "professional" price) such as clio, SMARRt and soundcheck use sound cards for audio measurements.