ok more tests
ch1 (L): 4011A
ch3 (R): CMC64
Source material: Time Difference by Hiromi's Sonicbloom, SACD
playback: Benchmark DAC2 > balanced out > single Dynaudio BM5A monitor at low volume
source material volume was the same for all tests. Volume level (SPL) estimated at 64-70 dB peak, 44-50dB RMS*
room noise estimated at less than 41-47 dB peak, 28-34 dB RMS*. it was difficult to tell if i was running into the noise floor of the recorder though
I also measured room noise at 31 dBA with iphone app. Room was quieter than my tinnitus. Room is in quietest corner of house, nothing electrical in the room except for the dynaudio monitor, the system feeding it via xlr was 2 rooms away.
on one sample (car_noise.flac) you can hear a vehicle accelerating through its gears all by its lonesome at 2AM. Thats through a closed window on a highway about a 1/3 mile away. Long story short, you would be hard pressed to be recording any source this quiet outside of nature settings
recorder was mounted right on top of stand, mics sticking right out the side, about 16" from the monitor
*the reason you see a 6dB range in estimated SPL is surprisingly the SPL calibrator i used read 6dB different on the schoeps and DPA caps (likely because of capsule back venting design, it is not super accurate for testing absolute measurements on different styles of directional mics, as i believe gutbucket pointed out to me along time ago. What was odd though, despite the mics reading so differently with the calibrator, they were actually equally sensitive within about 1 dB on all the tests. so the '94 dB levels' you see referenced in each test were the levels on the recorded tracks when the calibrator was used on each mic. likewise the calculated 'max SPL at FSD' is a range guessed from this. in other words, at those particular recording settings, you would need to hit that SPL before you clip the ADC. Of course some of the numbers are ridiculously high and the analog input would be beyond overloaded at 180-200+ SPL(!). id have to do some math to figure out what the actual clipping SPL numbers would be with each mic (i.e. what SPL causes +4dB/+24dB signal into the input). maybe i can try the calibrator with an omni and report back on that
anyway, on with the show. I was trying to test the following variables with the zoom
low vs high recording level where applicable
24bit vs 32 bit files
mic vs line in
i found it educational, i hope you do as well
test 1:
24 bit
mic-in
trim=+12dB (the minimum)
fader =-48dB (the minimum)
94dB levels = -44dB, -36 dB
corresponding SPL at FSD: 138dB, 130dB
peak program level = -74dB
RMS program level = -94dB
file was normalized approximately +73dB
test 2:
24 bit
line-in
trim=-8dB (the minimum)
fader =-48dB (the minimum)
94dB levels = -64dB, -56 dB
corresponding SPL at FSD: 158dB, 150dB
peak program level = -94 dB
RMS program level = -114dB
normalized approximately +93dB
test 3:
32 bit float
line-in
trim= -48dB (the minimum)
94dB levels = -124dB, -117 dB
corresponding SPL at FSD: 218dB, 211dB
peak program level = -154 dB
RMS program level = -173dB
normalized approximately +153dB
test 4:
32 bit float
mic-in
trim= -48dB (the minimum)
94dB levels = -104dB, -97 dB
corresponding SPL at FSD: 198dB, 191dB
peak program level =-134dB
RMS program level = -154dB
normalized approximately +132dB
test 5:
24 bit
mic-in
trim=+12dB (the minimum)
fader =+24dB (the maximum)
94dB levels = -44dB, -36 dB
corresponding SPL at FSD: 138dB, 130 dB
peak program level = -74dB
RMS program level = -94dB
normalized approximately +73dB
test 6:
24 bit
mic-in
trim=+75dB (the maximum)
fader =-48dB (the minimum)
94dB levels = (over FSD)
corresponding SPL at FSD: 80-85dB est.
peak program level = -11dB
RMS program level = -31dB
normalized approximately 10-11 dB
test 7:
tascam DR100mkiii
mic in
pad off
gain set to minimum (+20dB)
94dB levels = -22dB, -16dB
corresponding SPL at FSD: 116dB, 110dB
peak program level = -51dB
RMS program level = -70dB
normalized approximately 50dB
test 8:
tascam DR100mkiii
mic in
pad off
gain maximum (+56dB)
94dB levels = (over FSD)
corresponding SPL at FSD: est. 75-80 dB
peak program level = -15dB
RMS program level = -34 dB
normalized approximately 14dB
test 9:
tascam DR100mkiii
mic in
pad on
gain set to maximum (+31.5dB)
94dB levels = -10dB, -4dB
corresponding SPL at FSD: 104dB, 98dB
peak program level = -40dB
RMS program level = -58dB
normalized approximately 38dB
test 10:
tascam DR100mkiii
mic in
pad on
gain set to minimum (0)
94dB levels = -41dB, -34dB
corresponding SPL at FSD: 135 dB, 129dB
peak program level = -71dB
RMS program level = -90dB
normalized approximately 70dB
test 11
V3 with 30 dB of gain
peak program level = -66dB
RMS program level = -85dB
est. SPL at FSD: 125-130dB
normalized approximately 65dB in post
test 12
V3 with 70 dB of gain
peak program level = -27dB
RMS program level = -46dB
est. SPL at FSD: 85-90dB
normalized approximately 26dB in post
here is a folder with all six of the zoom tests and what i thought were the best test each from the Tascam and the V3. they are all cut to within a second of each other on start point so you can AB if you wish. imo its kinda all about the noise vs program material in the first few seconds, you'll be able to discard a few right off the bat. Then you can listen more critically to the ones which remain
https://drive.google.com/open?id=13nG-Z4kluspAzYrdrkO36glBGDrOAiS7