By astral_Signal
Tue May 28, 2013 8:52 am
Hi,
I have just received a racked pair of the 40-C2 Dorrough meters. I have a few queries about initial calibration.
I ultimately want to measure input level on an Akai MPC 1000 digital sampler:
16 bit / 44.1 Khz
Record input: balanced -40 dBu
Stereo Output: unbalanced +11dBu
All recordings are done via a Rane TTM-56 DJ Mixer:
Master output: 6 dB balanced / 0 dB unbalanced
Phono inputs: 40 dB gain
Unity gain = +4 dBu
On the initial calibration side of things, I have created a DAW session @ 16bit/44.1K, created two auxiliary channels with a signal generator on both (-20 dbfs 1KHZ sine tone), these two channels are sent out from my RME Fireface 800 @ +4dbU into a stereo line input on the DJ mixer. With the line input at unity and the master output at nominal, I then have two options to feed the Dorrough meter:
DJ Mixer balanced output peaks at +6 with the Dorrough meter level control flat
DJ Mixer unbalanced output can be calibrated to peak at 0 dB
I can also feed the meter a balanced input by using a half-normalled input from my patch-bay
Thus far I have calibrated the meter by feeding it the unbalanced output. I am concerned though that by using this calibration I will have a -6 db false reading, as I am recording into the MPC with balanced inputs.
I ultimately want to read the 40-C2 meter as a digital scale, where 20 db equates to 0 dbFS.
Is my calibration correct? I am currently metering a half-normalled balanced input, which seems to reflect the same readings on the MPC meter (which is non-numerical but is represented by a stereo bar).
I have just received a racked pair of the 40-C2 Dorrough meters. I have a few queries about initial calibration.
I ultimately want to measure input level on an Akai MPC 1000 digital sampler:
16 bit / 44.1 Khz
Record input: balanced -40 dBu
Stereo Output: unbalanced +11dBu
All recordings are done via a Rane TTM-56 DJ Mixer:
Master output: 6 dB balanced / 0 dB unbalanced
Phono inputs: 40 dB gain
Unity gain = +4 dBu
On the initial calibration side of things, I have created a DAW session @ 16bit/44.1K, created two auxiliary channels with a signal generator on both (-20 dbfs 1KHZ sine tone), these two channels are sent out from my RME Fireface 800 @ +4dbU into a stereo line input on the DJ mixer. With the line input at unity and the master output at nominal, I then have two options to feed the Dorrough meter:
DJ Mixer balanced output peaks at +6 with the Dorrough meter level control flat
DJ Mixer unbalanced output can be calibrated to peak at 0 dB
I can also feed the meter a balanced input by using a half-normalled input from my patch-bay
Thus far I have calibrated the meter by feeding it the unbalanced output. I am concerned though that by using this calibration I will have a -6 db false reading, as I am recording into the MPC with balanced inputs.
I ultimately want to read the 40-C2 meter as a digital scale, where 20 db equates to 0 dbFS.
Is my calibration correct? I am currently metering a half-normalled balanced input, which seems to reflect the same readings on the MPC meter (which is non-numerical but is represented by a stereo bar).
Technics SL-1200 MK2 / Jelco TK-850S / Jelco HS-25 / Nagaoka MP-500 / Graham Slee Reflex M / Coleman Audio M3PH MK2 / RME Fireface 800 AD/DA / Kali Audio IN-8 V2 / Akai MPC Live 2
