sm57 labeled "Unidyne III sm57 made in usa". This is the model Eric Johnson swears by along with many top producers and recording engineers.
the new ones do not sound as good!
its just another dynamic microphone, some people use it even for brushing their teeth-
some people claim that the new SM57's sound worse than the old ones,
USA pre 1985 vs. Mexico
problem was that Shure suffered a few years with non-authorized clones made in China.
some people tweak/modify the sm57/58
remove the transformer.
some add cappacitors to block the DC, remove DC.
old SM57 have dual low impedance.
SM stands for Studio Microphone, as the original market for all Shure SM mics were TV, radio, and recording studios.
The number "5" in the model indicates a dynamic mic element.
most Shure dynamic mic models start with the number "5".
The Shure model "55" had been around since 1939. "56", "57", and "58" were next.
is beleived that SM57/58 was imtroduced until 1965/66.
the MAX SPL of a dynamic microphone like the SM57/8 is frequency dependent. This means that low frequencies will produce distortion at a lower SPL than higher frequencies.
the frequency range to first exhibit distortion is centered around 100 Hz, close to the resonant frequency of the microphone's diaphragm. At 100 Hz, the measured MAX SPL is 150 dB SPL and the electrical output of the microphone is 0 dB V or 1.0 volts. Note this is a line level signal, not a mic level signal.
In the 1 kHz range, the SM58 measured MAX SPL is about 160 dB SPL due to the change in microphone sensitivity at the higher frequencies. The electrical output of the microphone at 160 dB SPL is +10 dBV or 3.2 volts.
In the 10 kHz range, 180 dB SPL is the MAX SPL of the SM58. However, this is a calculated measurement as Shure Engineering had no means to create such enormous and dangerous SPL. For comparison, NASA reports that a space shuttle launch measures 180 dB SPL and higher at 10 meters.
In the 20 kHz range, the MAX SPL is calculated to be around 190, due to the response falloff of the SM58. But now the point of absurdity has been reached because at 194 dB SPL the sound pressure varies from twice normal atmospheric pressure (at the wave peak) to a total vacuum (at the wave trough). Plus the sound source must be moving at the speed of sound just to generate a wave of this intensity.
In summary, a well-designed dynamic microphone of professional quality will never reach its distortion point in "normal" conditions. If one does encounter distortion when using a professional dynamic microphone for an extremely loud source, it is most likely that the electrical output of the microphone is clipping the input of the microphone preamplifier. [Remember that at 150 dB SPL, the SM58 will provide a line level output!] To solve this problem, an in-line attenuator ("pad") must be placed before the preamplifier input, or the microphone must be moved farther from the sound source. In general, the sound pressure level will decrease 6 dB for each doubling of the distance.
personally i find other mics from other brands better sounding, same price.
but the times i have used the sm5*s, were very interesting for rock guitar cabs. Some Links: Another Unidyne III USA SM57 vs Mexican SM57 Comparison Shure Americas | SM57 Instrument Microphone | Instrument Mic, Rugged, Touring Find Answers Shure SM57's FAKE !!!!!!! ????? FAKE SHURE SM57'S (including pics) How to detect a phony SM57? Chinese Shure SM7 clone Fake Shure SM57 Copy China pictures How to spot a fake sm57.
. Spotting a Shure SM57 clone | AudioTechnology Magazine Shure SM57's (Mexico, China, eBay) - Home Recording forums Jands - Shure Counterfeit Education Como distinguir un micro Shure original??