What actually happens with the signal gain structure within the miniDSP x-over?
I start with the “Input Signal RMS meter.
Measurement set-up:
Signal Source Hameg Function Generator HM8030-3 (Rout:50 Ohm)
Sinusoidal Signal Frequency:1281 Hz.
Instrument for mVrms and db measurement : Keithley 175 True RMS Multimeter
Instrument for mVpp measurement and clipping monitoring: Hameg Oscilloscope HM203-7
DUT:
MiniUSB kit: 2xIn, 4xOut. It is the 2V Input version. (5 Vdc supplied through the USB port. Output loaded with 10kOhm).
Plug-in: MiniDSP 2 Way advanced (Release date 17/02/2011)
I applied the sinusoidal signal to Input 1. The path through the outputs is flat.
X-over and filters are bypassed. Zero attenuation on the gain sliders.
Input 1 and Output 1 are monitored for level and waveform clipping.
On the attachment you can see the results of the measurement.
Two thinks are of importance here:
A. The flat output starts clipping when the Input RMS meter of the plug-in SW reads anything above the “–6” reading. (the output RMS meter for flat settings reads the same as the input meter).
The sinusoidal signal amplitude corresponding to this clipping threshold is 2.228Vrms (or 6.118Vpp).
B. The law that governs the input RMS meter of the plug-in does not follow the db law of neither voltage nor power measurements.
More downstream measurements tomorrow (hopefully).
>Note: B above seems to be a “technicality” but bears some importance for non-flat measurements (later).
George
I start with the “Input Signal RMS meter.
Measurement set-up:
Signal Source Hameg Function Generator HM8030-3 (Rout:50 Ohm)
Sinusoidal Signal Frequency:1281 Hz.
Instrument for mVrms and db measurement : Keithley 175 True RMS Multimeter
Instrument for mVpp measurement and clipping monitoring: Hameg Oscilloscope HM203-7
DUT:
MiniUSB kit: 2xIn, 4xOut. It is the 2V Input version. (5 Vdc supplied through the USB port. Output loaded with 10kOhm).
Plug-in: MiniDSP 2 Way advanced (Release date 17/02/2011)
I applied the sinusoidal signal to Input 1. The path through the outputs is flat.
X-over and filters are bypassed. Zero attenuation on the gain sliders.
Input 1 and Output 1 are monitored for level and waveform clipping.
On the attachment you can see the results of the measurement.
Two thinks are of importance here:
A. The flat output starts clipping when the Input RMS meter of the plug-in SW reads anything above the “–6” reading. (the output RMS meter for flat settings reads the same as the input meter).
The sinusoidal signal amplitude corresponding to this clipping threshold is 2.228Vrms (or 6.118Vpp).
B. The law that governs the input RMS meter of the plug-in does not follow the db law of neither voltage nor power measurements.
More downstream measurements tomorrow (hopefully).
>Note: B above seems to be a “technicality” but bears some importance for non-flat measurements (later).
George