The most precise measurements I do withOUT an USB-MIC. BUT it is complicated: a polarized MIC (200 V) capsule, a special PREpreAMP, a special Preamp (with calibrated meter) and the preamp of the AD-USB-Converter. Important for me is the level calibration. I use an USB-interface with stepped (repeatable !) gain. Also the preamp is switchable in 10 dB-steps. If just a level measurement is required I use the Preamp (and the mechanical Meter).
Of course USB-MICs must not be worse than standard MICs. BUT Precision USB-MICs use two AD converters with a gain-offset, switching intelligently from one to the other. It is difficult to cover the dynamic range of a good MIC capsule, even using 24 bit converters 2^24 == approx. 144 dB (ideal converter). Required is a dynamic range of > 150 dB ! usable > 25 bit !
The UMIK-1 has problems with the dynamic range, because of the (INTERNAL ! switchable) gain of 18 dB. The max. SPL level ist quite low. 18 dB gain is quite high . The noise of the mic is much higher than the 'bottom' of the AD-converter. May be the UMIKs converter is noisy losing some bit (effective 22 bit ?). I would be happy, if the standard gain of the UMIK-1 would bei DEcreased, probably the converter improved.
If the cal-file of the USB-MIC is properly done, a digital MIC like an USB-MIC has the big advantage, that you may measure ABSOLUTE level by software, right out of the box. You have got a good SPL-Meter. Other MICs require a special calibration procedure, that may be costly and/or inaccurate, allways time consuming. Often NOT repeatable (next measurement requires a calibration again). Also the frequency response of a digital MIC is 'fixed'. It may be somewhat corrected by correction tables. Some MIC amplifiers (USB-interface) show problematic (and also varying) frequency responses (at higher gains).
An ECM8000 is half the price of an UMIK-1, but my Phantom-MIC-USB-interfaces cost 15 to 50 x of an ECM8000. Precision needs money and brain. I have measured some really bad MIC-USB interfaces.
The only USB-MIC at (very) moderate cost, that is adaptable to a level calibrator is the UMIC-1 (please correct me), Though I judge the cal-level erroneous.
You may use a DAYTON UMM-6 if the cal-level is trustworthy. A Calibration may be cumbersome. (please correct me).
And I like the easy to handle USB-MIC , a small notebook/tablet and an USB-MIC. REW is easy to use. A trustworthy cal-file required.
One of my UMIK-1 ( just to verify) :
actual value 94.2 dB SPL (desired calibrator corrected 94.4), today 0.2 dB to low. -11.2 dB FS
( max SPL at 0 dB FS --> 105.4 or 105.6 dB SPL,
this is quite low, restricted application of UMIK-1)
my cal file ( corrected )
Sens Factor =4.6dB, SERNO: 703...
org cal file
Sens Factor =-0.015585dB, SERNO: 703...
gives wrong values
six decimal places are nonsense³ .
improved cal note
max spl = 105.6 dB SPL at 0 dB FS, SERNO: 703...
or
max spl =105.6dBSPL, SERNO: 703...
my proposal
does NOT work
*AKL CORRECTED 2018sep12 max105.4
Sens Factor =4.6dB, SERNO: 703...
comment capability of cal-file and software must be improved
This possibility to calibrate the absolute level is the main advantage of a digital output MIC : USB ,
also possible: SPDIF , aes3 , AES/EBU.
HIGH SPL oder low (noise) require complicated equipment, also 40 or 80 kHz measurements.
Also high precision. Sometimes many different software may be required ( REW , arta , HPWworks , HobbyBox , digicheck , ... ). My USB-interface allows easy to handle , easy to route digital outputs. The UMIK-1 driver behaves a littel 'bitchy'.
I use RME (
www.rme-audio.com ) UC UCX UFX .
An inexpensive NON-USB-MIC will definitely allow higher SPLs than common USB-MICs.
Have a nice noise- and distortionless 2019
(and a low SPL at home, night)
- akl -