Nice find!
Google Translate did a pretty good job on this PDF
http://casa.accattatis.org:9090/Articoli su VA -- Articles on VA/visual_analyser_part1.pdf
But I had to download it then choose it from Google Translate. All images were gone, but the text is pretty good. There may be a better way.
Google Translate did a pretty good job on this PDF
http://casa.accattatis.org:9090/Articoli su VA -- Articles on VA/visual_analyser_part1.pdf
But I had to download it then choose it from Google Translate. All images were gone, but the text is pretty good. There may be a better way.
Was just doing some vibration analysis with VA and fooled around with the DC Removal. With my EMU-0202 I get a rise in the spectrum down at a few Hz. This is regardless of signal or not. With the gain on the EMU set to minimum, everything (the noise floor) is at about (uncalibrated) -130 dB. The far left end is at about - 90 dB. If I click the DC Removal, the left end goes to the same, or a bit lower, than everything else. IMO, there's some tiny offset in the EMU at the -90 dB level, that the program can filter out. AFAIK, one could remove all the AC coupling from a sound card and get it to go to DC, except for the fact that it probably runs single supply and you'd have to supply an offet.
It certainly would be helpful to have a fluent Italian speaker on the case, not necessarily to translate the articles (although that would be great and would probably get me off the hook entirely!), but at least to search out issues such as how to interpret A cross B. Any offers, or do we know any Italian speaker members we could lean on? My Italian is largely limited to the culinary and musical.
On the A cross B issue, Simon B has also raised doubts (in a private email). He also wonders if it is some sort of cross correlation feature. We'll have to think out how to test that theory, unless someone can find it in the Italian.
Ah, Pano, I now see your recent post. I tried to convert this article via Google Translate, but when I tried to copy from the .pdf, I got an internal error message. Suggestions?
Ah, wait, I found I could copy it as text, and then import the text into Translate. Unfortunately, I think this all relates to the 2011 or earlier versions, and the A cross B feature wasn't in them. But we can probably use it to crack other conundra. Thanks, Pano.
Terry
On the A cross B issue, Simon B has also raised doubts (in a private email). He also wonders if it is some sort of cross correlation feature. We'll have to think out how to test that theory, unless someone can find it in the Italian.
Ah, Pano, I now see your recent post. I tried to convert this article via Google Translate, but when I tried to copy from the .pdf, I got an internal error message. Suggestions?
Ah, wait, I found I could copy it as text, and then import the text into Translate. Unfortunately, I think this all relates to the 2011 or earlier versions, and the A cross B feature wasn't in them. But we can probably use it to crack other conundra. Thanks, Pano.
Terry
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Hi Terry,
I'm not an expert on measurement tools (I don't have an oscilloscope too) but if you tell me what is your doubt and possibly point me to the italian manual I'll do my best to help.
Dario
It's been long enough that I can post this. Haven't tried it on the latest versions, but just put the text into a notepad file and name it something like A_weighting.cmp
;A-weighting
20 50.4
25 44.8
31.5 39.5
40 34.5
50 30.3
63 26.2
80 22.4
100 19.1
125 16.2
160 13.2
200 10.8
250 8.7
312 6.7
400 4.8
500 3.2
625 2.0
800 0.8
1000 -0.0
1250 -0.6
1600 -1.0
2000 -1.2
2500 -1.3
3120 -1.2
4000 -1.0
5000 -0.6
6250 0.1
8000 1.1
10000 2.5
12500 4.3
16000 6.7
20000 9.3
;A-weighting
20 50.4
25 44.8
31.5 39.5
40 34.5
50 30.3
63 26.2
80 22.4
100 19.1
125 16.2
160 13.2
200 10.8
250 8.7
312 6.7
400 4.8
500 3.2
625 2.0
800 0.8
1000 -0.0
1250 -0.6
1600 -1.0
2000 -1.2
2500 -1.3
3120 -1.2
4000 -1.0
5000 -0.6
6250 0.1
8000 1.1
10000 2.5
12500 4.3
16000 6.7
20000 9.3
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I haven't used or checked this one yet-
;C-weighting
20 6.2
25 4.4
31.5 3.0
40 2.0
50 1.3
63 0.8
80 0.5
100 0.3
125 0.2
160 0.1
200 0.0
250 0.0
312 0.0
400 0.0
500 0.0
625 0.0
800 0.0
1000 0.0
1250 0.0
1600 0.1
2000 0.2
2500 0.3
3120 0.5
4000 0.8
5000 1.3
6250 2.0
8000 3.0
10000 4.4
12500 6.2
16000 8.6
20000 11.3
There should be a subdirectory called Frequency Compensation. Put 'em in there and select it as microphone compensation under spectrum. I think the program installs with some standard mic compensations for SM57, SM58 and others. You'd have to combine compensation for a specific mic and the weighting if you wanted both. That probably means using fewer points for the weighting (yecch) or interpolating on the mic curve, since most people don't have hi res data on their mics. Mics are pretty flat, so it might be easy. IMO, VA makes a great little acoustic analysis program when combined with a mic.
;C-weighting
20 6.2
25 4.4
31.5 3.0
40 2.0
50 1.3
63 0.8
80 0.5
100 0.3
125 0.2
160 0.1
200 0.0
250 0.0
312 0.0
400 0.0
500 0.0
625 0.0
800 0.0
1000 0.0
1250 0.0
1600 0.1
2000 0.2
2500 0.3
3120 0.5
4000 0.8
5000 1.3
6250 2.0
8000 3.0
10000 4.4
12500 6.2
16000 8.6
20000 11.3
There should be a subdirectory called Frequency Compensation. Put 'em in there and select it as microphone compensation under spectrum. I think the program installs with some standard mic compensations for SM57, SM58 and others. You'd have to combine compensation for a specific mic and the weighting if you wanted both. That probably means using fewer points for the weighting (yecch) or interpolating on the mic curve, since most people don't have hi res data on their mics. Mics are pretty flat, so it might be easy. IMO, VA makes a great little acoustic analysis program when combined with a mic.
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Yep, that worked and was very easy. I just took my mic cal file and made a copy in the same folder as VA. Changed the extension to .cmp and loaded it in. So far, so good. I didn't even remove the phase column.
I do now see that the furthest left bar is way up. Turned on DC remove and it's gone. Will check further.
I do now see that the furthest left bar is way up. Turned on DC remove and it's gone. Will check further.
Hi Dario. Thanks for your offer of help!
I'm not sure if there is an Italian manual. But we do know that there are some papers, as identified by mickeymoose:
http://casa.accattatis.org:9090/Arti...0on%20VA/?date
And the articles in Nuova Elletronica at the right hand side of:
Visual Analyser 2011 XE
If you could have a flick through these and see which ones have any practical information, we could concentrate on them in future.
Some of them may be able to be translated into English using the Google translator. Let us know of any that you think could be translated (eg clean text) and would be useful.
Terry
Conrad and Pano - I'm not sure how the topic of compensation curves came up, and I haven't got this far myself. But just to mention, on the Settings / Spectrum window, there are buttons marked Compensation and Custom Spectrum.
Compensation offers the standard A, B and C curves as well as the ability to invoke .cmp files.
Custom offers more capacity, including the ability to define musical presets, like flute and harpsichord. Now that has to interest a flute-maker and sometimes harpsichord-maker (like me), surely! Haven't a clue yet what it's about!
There is so much in this thing! Bravo Alfredo!
Terry
Compensation offers the standard A, B and C curves as well as the ability to invoke .cmp files.
Custom offers more capacity, including the ability to define musical presets, like flute and harpsichord. Now that has to interest a flute-maker and sometimes harpsichord-maker (like me), surely! Haven't a clue yet what it's about!
There is so much in this thing! Bravo Alfredo!
Terry
Hi Terry,
you're welcome.
yesterday I've had a brief read of those docs but didn't find anything on A/B and B/A.
I'll check again tomorrow more in depth and try to find other docs.
Dario
Good man yerself, mickeymoose! Hey, from one definite maybe, we're gathering some momentum here!
Gulp, can I keep up?
Terry
The flute and harpsichord were listed among others under Music Presets (tempered scale) in the Define Custom Spectrum window, available from the Spectrum tab of the Settings window. (How many layers does this onion go down?) As I say, I haven't yet investigated it.
Yeah, I think I quipped in an early article that we would spend quite some time there. We certainly will need to!
I think we're seeing that VA is not just a Scope and FFT (and all those other things I listed in the Intro article. It really opens some possibilities for people doing other forms of audio-frequency research. And possibly further, who knows. Conrad mentioned vibration. ECG? Foetal heart beat monitor for nervous mums-to-be?
Terry
Great, Dario, thanks. It wasn't so much the A/B and B/A that were causing us problems (I think), but the A cross B and B cross A. I interpreted them as meaning A times B, etc, and couldn't think of an application for them. But more alert contributors think it might be a cross-correlation feature. So do please keep a lookout for those!
Terry
We must have different version or I'm missing some parts. My define custom spectrum window has no musical presets.
Attachments
Hmmm, just thinking on mickeymoose's kind offer of sharing his pcb layout with others who might like to build the front end. It would be really good to be able to read the associated Nuova Elettronica article in English. I downloaded it from Alfredo's site, but found I couldn't even print it out, let alone copy it to submit the text for electronic translation. Anyone have any suggestions as to how we can break through the language barrier easily?
When I worked in community radio many years back, I decided on the purchase of an Italian-made transmitter. The station manager was surprised - what would Italians know about radio? (We tend to have a rather lop-sided view of Italians in Australia - we tend to hear more about food, fashion, Roman antiquities, fast cars and dodgy politics than the industrial side.) I quipped back, ever hear of Guglielmo Marconi? He was suitably chagrined.
Terry
When I worked in community radio many years back, I decided on the purchase of an Italian-made transmitter. The station manager was surprised - what would Italians know about radio? (We tend to have a rather lop-sided view of Italians in Australia - we tend to hear more about food, fashion, Roman antiquities, fast cars and dodgy politics than the industrial side.) I quipped back, ever hear of Guglielmo Marconi? He was suitably chagrined.
Terry