That make absolute zero sense.
Sounds rather like a big judgement to me.
Maybe ask about somebody's meaning and intentions fist?
Talking about complaining and negativity ......
eg. Before:
Not the same size.AFTER:
Not the same scales on the diagram.
Not the same aspect ratio.
...
Nothing to compare.
Worthless effort.
Bernd,
I noted that the Y axis is not the same, but was not aware the image size was not.
It can be misleading I see your point.
Please look at the region of interest- the yellow box:
The brown line is flat, whereas in the previous it is rising.
My updated image was to show that ensuring that noise is minimised is critical to measuring any distortion.
Anyway noise- in the path affects ability to measure distortion- this can come from the environment, electronics (DAC, amplifier, microphone, preamp, ADC) or even processing can affect the ability to measure HD (or IMD)
I noted that the Y axis is not the same, but was not aware the image size was not.
It can be misleading I see your point.
Please look at the region of interest- the yellow box:
The brown line is flat, whereas in the previous it is rising.
My updated image was to show that ensuring that noise is minimised is critical to measuring any distortion.
Anyway noise- in the path affects ability to measure distortion- this can come from the environment, electronics (DAC, amplifier, microphone, preamp, ADC) or even processing can affect the ability to measure HD (or IMD)
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REW's worst flaw is image export. There are obviously hundreds of ways to create graphics with different bad designs.
A yellow box is no remedy.
Best regards
Bernd
A yellow box is no remedy.
What made the difference?
Best regards
Bernd
Any fault in export of graphics lies with me. I can't recall if I disclosed this previously but my measurement PC is a silent PC with a 27" 4K display.
I save all my measurement data to the cloud, and then view/interpret the graphs from the comfort of my Lenovo ultralight laptop (Lenovo X1 Carbon)
Unfortunately these two are NOT synchronized. For starters my laptop is running Windows 10, with 1900x1200 16:10 display running at 125% zoom, whereas the lab machine has a 27" 4K display running Windows 11. Sometimes I discover something novel, and in my haste, I post graphics directly from the lab machine.
So the graphics may be slightly/ ?completely different!
Oh and...if you knew how that yellow box got there, you'd probably 🙄 ... 😡
Perhaps I should have run that one by my microphone brains trust, and advisor on graphical design variables that bias the interpretation of data presented in the graph. Now I've posted misleading graphics publicly, and unable to retract them. 😳
see post-
https://www.diyaudio.com/community/...al-microphones-for-diyers.412011/post-7758672
and
https://www.roomeqwizard.com/beta.html
V5.40 beta 45 27th July 2024
PS.
If someone could assist me in "synchronizing" both setups so they are exactly same, I'd love to hear it.
I save all my measurement data to the cloud, and then view/interpret the graphs from the comfort of my Lenovo ultralight laptop (Lenovo X1 Carbon)
Unfortunately these two are NOT synchronized. For starters my laptop is running Windows 10, with 1900x1200 16:10 display running at 125% zoom, whereas the lab machine has a 27" 4K display running Windows 11. Sometimes I discover something novel, and in my haste, I post graphics directly from the lab machine.
So the graphics may be slightly/ ?completely different!
Oh and...if you knew how that yellow box got there, you'd probably 🙄 ... 😡
Perhaps I should have run that one by my microphone brains trust, and advisor on graphical design variables that bias the interpretation of data presented in the graph. Now I've posted misleading graphics publicly, and unable to retract them. 😳
The processing/display of data...
see post-
https://www.diyaudio.com/community/...al-microphones-for-diyers.412011/post-7758672
and
https://www.roomeqwizard.com/beta.html
V5.40 beta 45 27th July 2024
- Changed: Use frequency-dependent windows to reduce the noise floor of sweep distortion measurements
- Fixed: Index out of bounds when saving an RTA peak measurement with multiple inputs and group averages enabled
- Added: A new group can be generated from the Measure dialog
- Fixed: Long group names could disrupt the Measure dialog layout
- Fixed: Sweep distortion noise floor could be plotted too high
PS.
If someone could assist me in "synchronizing" both setups so they are exactly same, I'd love to hear it.
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The D2s are the same...REW 5.31 Stable release
REW 5.40 beta 46- fixed rising noise floor.
but one of the D3s ist wrong
(REW 5.40Beta 46+)
The cursor 1k readout of D3 in the legend is wrong by more than 3dBr
A manual readout of the graphs at 1k results in -45dBr for D3
The manual readout is the same like in the legend: -45dBr D3
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If REW had storable graphics (export) settings, then your efforts would be much easier.
Screenshots always differ between computers or forum members. Remember the old times when people pointed their digital camera at the CRT - or the 1/3oct analog pink noised RTA?
Given the current state of REW and Windows, you can't even set and maintain your own standard.
Best regards
Bernd
Yes it can be a challenge!
That is detective work Bernd!
This is how we move forward to making our tools better. I have noted also your suggestion that the right hand vertical scale
also includes % distortion figures for 3%, 0.3% etc that aligns with -30dB, -50dB (we odd fellows deserved recognition too!)
as well as the unusual behaviour in the Unusual behaviour in RTA —> stepped sine
As we progress, my goal is that we can demonstrate a solution for taking frequency response, harmonic distortion, IMD measurements with a level of precision, accuracy and affordability that DIYers can choose from, based on (repeatable) data, instead of reputation or opinion.
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I don't follow the logic. The reference in the graph (post #144) at 1 KHz is 97.3 dB. When I enlarge the graph I eyeball the D3 1 KHz level at 56 dB. So the D3 dB reference (dBr) value is 56 - 97.3 = -41.3 dB. That's 0.1 dB different from the REW value. Am I missing something?
52 dBr !
@ernperkins : Thank you for checking my post. I really appreciate this !!
@tktran303 : I'm done with REW.
That was a difficult decision for me. A full run of STEPS 1/48oct takes minutes.
Your displayed work with REW took me months, atop the wasted years with REW and microphone distortion from others at diyAudio.
I swallow the Tooleian blue pill now.
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STEPS is good. But what about full polar measurements every 10 degrees in both horizontal and vertical plane?
Also, the higher microphone distortion may not matter for high distortion drivers! The whole measurement chain just has to be -20dB lower distortion than what you want to measure.
No need to give up yet!
Corrigenda:
52dB D3 readout at 1k
...then the scale was out of sight
Best regards
Bernd
The fundamental level which is used as the reference for harmonics may be the cursor frequency or the frequency of the harmonic according to the setting of "Use harmonic frequency as ref" in the graph controls, there is more about that in the help:
The harmonic and THD plots in normalised mode use the level at the fundamental for each frequency as their reference by default - for example, the distortion figures for each harmonic at 1 kHz will depend on the level of the fundamental at 1 kHz. If Use harmonic frequency as ref is selected the reference will be the frequency of the harmonic - for example, at 1 kHz the 2nd harmonic figure will depend on the level of the fundamental at 2 kHz, the 3rd harmonic will depend on the level of the fundamental at 3 kHz and so on. This follows a recommendation made by Steve F. Temme in "How to graph distortion measurements" presented at the 94th AES convention in March 1993. If the response of the system being measured is flat this makes no difference to the results, but when the response is not flat (as for most acoustic measurements) it can remove the influence of the loudspeaker's fundamental response from the distortion figures. As an example, suppose the loudspeaker response was flat apart from a 6 dB peak at 2 kHz. 2 kHz is the 2nd harmonic of 1 kHz, so the 2nd harmonic level shown at 1 kHz will be increased by 6 dB due to the boost in the fundamental when using the excitation frequency as the reference. Similarly the 3rd harmonic level at 667 Hz (2/3 kHz) will be boosted by 6 dB. If the harmonic frequency were used as the reference the distortion figures would not show this boost. Using the harmonic frequency as the reference also provides a more meaningful view of distortion at frequencies below the LF roll-off of the system as otherwise the distortion levels are boosted as the level of the fundamental drops. Note that this option will not affect the traces when the plot is not normalised, but will still affect the values in the legend if the distortion figures are set to read in percent or in dB relative to the fundamental.
The harmonic and THD plots in normalised mode use the level at the fundamental for each frequency as their reference by default - for example, the distortion figures for each harmonic at 1 kHz will depend on the level of the fundamental at 1 kHz. If Use harmonic frequency as ref is selected the reference will be the frequency of the harmonic - for example, at 1 kHz the 2nd harmonic figure will depend on the level of the fundamental at 2 kHz, the 3rd harmonic will depend on the level of the fundamental at 3 kHz and so on. This follows a recommendation made by Steve F. Temme in "How to graph distortion measurements" presented at the 94th AES convention in March 1993. If the response of the system being measured is flat this makes no difference to the results, but when the response is not flat (as for most acoustic measurements) it can remove the influence of the loudspeaker's fundamental response from the distortion figures. As an example, suppose the loudspeaker response was flat apart from a 6 dB peak at 2 kHz. 2 kHz is the 2nd harmonic of 1 kHz, so the 2nd harmonic level shown at 1 kHz will be increased by 6 dB due to the boost in the fundamental when using the excitation frequency as the reference. Similarly the 3rd harmonic level at 667 Hz (2/3 kHz) will be boosted by 6 dB. If the harmonic frequency were used as the reference the distortion figures would not show this boost. Using the harmonic frequency as the reference also provides a more meaningful view of distortion at frequencies below the LF roll-off of the system as otherwise the distortion levels are boosted as the level of the fundamental drops. Note that this option will not affect the traces when the plot is not normalised, but will still affect the values in the legend if the distortion figures are set to read in percent or in dB relative to the fundamental.
The biggest problem for me is still that the calibration procedure is very broken.
I don't have the big differences that you're talking about.
The results between ARTA en REW are pretty consistent within margin of error.
And those results are consistent again with measurements from others.
The problem I have with ARTA is that it either takes forever, or that the distortion graph can't be changed (for absolutely no particular reason) to something that makes sense.
Because this option used to be greyed out for a very long time.
Obviously a sweep is better, but just not always that pleasant to use.
There are plenty of situations when noise is just fine to get some ballpark figure done or something like a freq resp etc.
Broken how? If you need individual inputs on the same device to have different calibrations make sure the option for that is selected:
D