With music and speech and noises and what have you, distortion products as IM and HD below 60dB are barely detectable by even trained individuals (exceptions apply), at least when listening for recreational or educative purposes other than the infamous 'critical listening' as kind of a contemporary sport Get yourself a measuring microphone, even if it has to be cheap for obvious reasons. I did, it is way higher (w/ my Panasonics) than HD.Ĭlick to expand.I advocate the contrary. Hence, no interest.Ĭoming back to microphones, better measure the intermodulation. IM is too complicated to be communicated to the general public. That room effect will yield the very same effect, a shift in the sonic signature, as harmonic distortion does.Īnother is intermodulation. Even tens of percent of HD won't shift the sonic impression of a bass instrument, let alone the room's reverberation, that will introduce strong comb filter effects, altering the effective distortion figures, and-you name it, the relations of the musical harmonics to the base tone. It went to even inventing 'new' forms of distortion, that were, sure enough, an unforgivingly brutal threat to the music.Īre we starting that same game with speakers now?Īgain and reiterated, harmonic distortion is at some point completely masked by the musical content that needs its own harmonics to simply exsist! In bass a grand total of hundreds (!!) of percent of harmonics is not to be accepted, but to be appreciated. Amplifier distortion became a fetish in the 70s (last century) as soon as the numbers went down, and so could be used in advertizing, batteling the competition. All the trouble is hidden behind massive feedback, so that one won't tell a reasonable from a not-so good model by its distortion figures anymore. Today with lowest distortion high gain op amps you can't no longer count (and memorize) the zeros following the decimal point. Distortion of less than 1% were considered exceptionally good. 1 m), is it valid to afterward move the mic closer to increase the maximum measurable SNR?Ĭlick to expand.In the old days my granny would listen to a valve powered radio. Taking Earthworks for example, in advertising "140dB SPL rating without distortion" and "20dB SPL equivalent (A weighted)" self-noise, does that mean that the microphone's distortion products will remain below the 20 dB self-noise floor until the microphone starts receiving more than 140dB SPL? If so, am I right to assume that with a sufficiently large input signal (the microphone sufficiently close to the transducer after setting the reference level at the reference distance) and sufficiently low ambient noise, these Earthworks microphones could measure up to 120 dB SNR or amplifier-level 0.0001% THD, only limited by the microphone preamp's and whatnot's own noise and distortion? Now, Brüel & Kjær specifies a "3% distortion limit" coincident with the stated dynamic range", whereby if the distortion curve is similar to the one shown in, then it is perhaps rather around 20 dB below the max SPL that the distortion products start rising above mic's self-noise, suggesting a maximum measurable SNR of 100 dB or 0.001% THD (though that PDF seemed to show a floor of around 0.15% THD which is well above the self-noise at those levels).įurthermore, in setting the reference level (e.g. Not all measurement microphone manufacturers publish their distortion measurements. In short, how can we know if a measurement microphone is suitable for measuring speaker distortion with respect to frequency at some reference down to, say, 0.01% THD?įorgive any misconceptions I have in the following:
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