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Author Topic: Schoeps CMR (mshilarious please enter!)  (Read 23656 times)

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Offline DSatz

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Re: Schoeps CMR (mshilarious please enter!)
« Reply #105 on: February 05, 2019, 01:02:56 PM »
jerryfreak, your post interests me a lot since I would like to consider a similar, possible arrangement for myself some day.

My one observation is that I think 130 dB SPL as a ceiling value is too high. I think you can afford to let more of the signal from the microphones into the recorder's preamps, in other words. 130 dB SPL is typical of a brass instrument such as trombone or trumpet playing at maximum volume, if the microphone is less than a foot away from the instrument's bell--or if a person is totally screaming (or a trained operatic soprano is hitting a high note with full force) directly into a microphone (say 2" distance or less). If you have even a one-meter distance from things like the above, the levels at the microphone won't reach 130 dB SPL.

130 dB SPL on any ongoing basis is so loud that no human being (except one who is already profoundly deaf) would voluntarily stay in the same room with it. It would engage your fight-or-flight mechanism to an almost uncontrollable extent. At ~120 dB SPL, if you're standing next to someone and you want to tell them something, you'd have to yell to be heard. At 130 dB SPL, even if you and the other person could withstand it somehow, you could scream all you wanted, and they still wouldn't hear you.

Does that explain the difference? Being in a 130 dB SPL environment for more than a small number of seconds would be torture, and I don't use that word lightly. Your legs would probably be running for the nearest exit before you even realized they were.

For decades, the overload point of many professional condenser microphones was around 120 dB SPL, and that level is rarely reached in normal recording work. I think highest level I ever legitimately encountered was a single peak at around 122 dB SPL, which was during a vocal master class. It came from a very strong operatic soprano doing a special exercise that required considerable warmup, followed by a strong attack on a note in the top register; the microphone was six inches in front of her. It slightly overloaded the preamp that I was using at the time, but not the microphone. I think that if I were you in the situation you have, I would go another 6 dB and draw the line at 124. I think that should be more than enough headroom for any semi-distant recording that I might ever do; even that might well be too cautious, to the detriment of quiet recordings.

Note that wind can produce similar levels of output from a condenser microphone capsule as extremely high SPLs, but I assume that you would use windscreening if you were recording outdoors.

--best regards
« Last Edit: February 05, 2019, 10:13:55 PM by DSatz »
music > microphones > a recorder of some sort

Offline jerryfreak

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Re: Schoeps CMR (mshilarious please enter!)
« Reply #106 on: February 06, 2019, 12:36:56 AM »
thanks ill be experimenting

i bought a cheap handheld spl meter that may not be absolutely accurate but will be a reference for me to test since im trying to set up both the schoeps and the 4061s

i plan on testing the cmr powered by a regulated power supply at its min and max voltage to get an idea of the difference in output level (and if there is any value in adding additional power when you have a device like the lectro that provides 5V).

basically ill be close-ish mic'ing a monitor at a repeatable, measurable output level. i guess ill experiment with a 5K pot to see what works as far as matching mic input to the recorder. 130 dB was an extreme upper limit, and yes sometimes when stack taping im in places where it is uncomfortably loud (with earplugs). ill prob try to match 120 dBA to -10 dBFS jsut to give myself a little space for transients

Offline jerryfreak

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Re: Schoeps CMR (mshilarious please enter!)
« Reply #107 on: February 09, 2019, 08:43:04 PM »
feels weird updating 2 threads, but i reported my results with testing the CMR+SPDR over in the SPDR thread

http://taperssection.com/index.php?topic=187843.msg2290730#msg2290730

Offline DSatz

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Re: Schoeps CMR (mshilarious please enter!)
« Reply #108 on: February 10, 2019, 12:23:35 AM »
"A" weighting at 100+ dB SPL is absurd. That curve is designed to mimic the ear's sensitivity at 40 phons, which at 1 kHz is equivalent to 40 dB SPL. Above that level, progressively less and less treble emphasis is needed since the ear/brain become more nearly linear in its/their sensitivity. See https://en.wikipedia.org/wiki/Equal-loudness_contour

--best regards
music > microphones > a recorder of some sort

 

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