Audiophile_AU
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- Dec 18, 2023
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- Main Amp
- Powersoft or QSC pro power amplifiers
- DAC
- Eversolo DAC-Z6
- Universal / Blu-ray / CD Player
- Audacity
- Center Channel Speaker
- VArious, under R&D measurement
Hi John, all.
I have been using REW for a few months and have got used to its way of doing things. I am mostly using it to measure free field loudspeaker frequency responses, using a tower and turntable for off-axis measurements to then create text files and import them into VituixCAD to make nice looking heat maps, etc.
A problem has been to force REW to keep the same start time of the measurement window. For some off-axis measurements the reflection from the side walls is considerably stronger than the shortest path sound, as these loudspeakers are horn loaded devices and are quite directional. I have found I have to check every off axis measurement to make sure the window is at the correct timing.
Next challenge:
I have set up a separate player (Audacity) through a DAC to play M-Noise (I think its official name is now Music Noise), and can view the RTA etc, and save it into an mdat file. However, AES75 wants to use a normalised measurement as the reference (baseline?) such that, when the input signal level is increased by a particular amount, the resulting measurement response can be offset downwards by that amount to overlay the responses and inspect for any deviations eg broad dips through some frequency ranges due to thermal heating of the loudspeaker reproducing that frequency range. AES75 also asks (requires) that the coherence be inspected for any reduction, used a proxy for the signal to noise /distortion ratio.
Questions:
1. How do I save the mdat of an RTA as a reference or cal file such that I have a (more or less) uniform response as the base line?
2. Are there any plans to introduce the number crunching needed to display coherence. I notice that for Measure SPL from REW or from File mandates a sweep measurement
Best regards from Down Under
David
I have been using REW for a few months and have got used to its way of doing things. I am mostly using it to measure free field loudspeaker frequency responses, using a tower and turntable for off-axis measurements to then create text files and import them into VituixCAD to make nice looking heat maps, etc.
A problem has been to force REW to keep the same start time of the measurement window. For some off-axis measurements the reflection from the side walls is considerably stronger than the shortest path sound, as these loudspeakers are horn loaded devices and are quite directional. I have found I have to check every off axis measurement to make sure the window is at the correct timing.
Next challenge:
I have set up a separate player (Audacity) through a DAC to play M-Noise (I think its official name is now Music Noise), and can view the RTA etc, and save it into an mdat file. However, AES75 wants to use a normalised measurement as the reference (baseline?) such that, when the input signal level is increased by a particular amount, the resulting measurement response can be offset downwards by that amount to overlay the responses and inspect for any deviations eg broad dips through some frequency ranges due to thermal heating of the loudspeaker reproducing that frequency range. AES75 also asks (requires) that the coherence be inspected for any reduction, used a proxy for the signal to noise /distortion ratio.
Questions:
1. How do I save the mdat of an RTA as a reference or cal file such that I have a (more or less) uniform response as the base line?
2. Are there any plans to introduce the number crunching needed to display coherence. I notice that for Measure SPL from REW or from File mandates a sweep measurement
Best regards from Down Under
David
