Collecting Spectrographic data

[Trevor Gore]

Hmmm, not sure I can say much more, Barry.

In Version 9, if you go to Settings, Capture Scope/Spectrum then set "spectrum average for EDIT window" to 10 buffers you should be OK. It shouldn't matter what the scope settings are, as they should only be active when you capture scope data (we're capturing spectrum data), but mine is set to 1. If you then hit the "start capture spectrum" button, you should see a blue bar increment up to full length in 10 parts. Each increment brings a screen refresh on my computer. If you don't see a refresh, maybe you can use the blue bar incrementation to synchronise your timing?

The actual timing is dictated by the FFT size and Frequency sampling which is set in the Settings, Main window and should be as shown in the set-up instructions on my website (16384 and 11025, giving a bandwidth to 5512Hz and a spectrum line resolution of 0.67Hz).

[Barry Daniels]

Trevor, that helps. Knowing that each increment in the progress bar represents a buffer is what I was missing. My screen showed no visible refresh. And knowing that the capture scope setting is irrelevant especially helps. I think I can take it from there. Thanks

[Barry Daniels]

Does anyone know if Visual Analyzer will work on a Windows 8 platform?

[weslewis]

I use it on windows 8!! no problems,Va 8

[Dave M]

Hope this may reach the right people. The post title says it all...

Well I really need some help here. I am trying to analyse my resonant frequencies. I have a closed box but I really need to be able to this through the build.

I have tried to follow all the guidance in the GG books and have tried to follow the threads in this forum but am beginning to feel like a real idiot! I am getting spectra that don’t look anything like the nice smooth curves with clear peaks of the relevant frequencies that are being shown. Rather I have got a whole bunch of peaks, particularly at higher frequencies with much higher amplitudes and no distinguishable ones at the expected top and body frequencies.


I have reproduced the hardware, I have the Shure PG 57 mic going directly into the sound card on a Dell Laptop. I am placing it 300 maybe 400 mm from the soundboard. I am tapping with the erasor on a stick (and yes my wife has had some funny things to say about that!).

I realise that I really don’t know how to drive Visual Analyser. No I don’ t have any previous experience in this area.

So I have set the FFT sample size and frequency as suggested. I can see the transient view of the spectrum in the lower window. At first I used to try to grab that by clicking on capture spectrum when it appeared clearest. Then I noticed the hold button. Is that the way to go. And what exactly is it doing?
Then looking at the captured spectrum , a) it doesn’t always seem to correspond to what I was looking at on the transient and b) it covers the whole frequency range up to about 5 and a half kilo hertz. I discovered you can select a bit of that range with the cursor but can’t we select the range of interest...

Woodsy you seemed to have had similar problems but you cracked it. And Dominic you also seemed to have worked it out.

So please please will someone tell me all the details of how to use this software.

Thanks, going mad Dave M

[jeffhigh]

Dave, Have you set the Capture section under settings-- use 10 and 10
turn on using the on button top left corner then click "capture" just over halfway down the right side and it will start recording and come up with spectrum and phase graphs at the end. Get rid of the phase and use the buttons to get the magnification.
Try the mic a metre away

[Dave M]

Jeffhigh thanks for pointing me in the right direction. I am already getting something more realistic. I also eventually found Dominics instructions on VA. I 'm still learning how to get around these forums. Cheers Dave

[printer2]

Looking through the old threads and thought I might add my two cents to this one as far as mics go. I picked up a usb mic for a couple of bucks at a thrift shop and it seems to work well down to low frequencies. No need for adapters to get a mic into a sound card, just plug and (once the driver is installed) play.

[blackalex1952]

Hi everyone. I haven't read all the posts re visual analyser, but have looked at quite a few. A couple of thoughts re microphones and tea leaf reading and useful iPhone apps :
Firstly, there is a waveform generator in Visual Analyser which can be used to drive a loudspeaker if you have an external amp. I myself use an iPhone app (see below)
Visual Analyser also has some microphone compensation presets-
On a PC: My Computer-program files-Sillanum Soft-VA-Frequency Compensation. Right click on one of them and "open with" Visual Analyser...The list is incomplete, I haven't tried it yet as I just discovered the folder, but it has some common microphones-AKG 1000,EV 257B,RADSHACK,SM57,SM58
The iPhone apps I have discovered, many of which are free, are:
Percentages
Radius Calc
Fret Calc....any scale length you want
Convert Units useful conversions
Fraction Plus concerts fractions
Poly Tune this one costs $$ but really works just as well as the stomp box model
Note Freak lists the frequencies in Hz of every note
Signal Gen for the tea leaf readers
iStroboSoft the app version of the Petersen strobotuner---costs $$ but works a treat, I use it for intonation work
RTA -Real Time Frequency Analyser-costs but good, I mainly use it for tuning my PA if I really cant hear my frequencies well, eg ear fatigue.
and a TUNING FORK which is very useful!

[Dave M]

Well even after all this time I am still getting tripped up by Visual analyser.
Apologies if this is obvious to everyone else but...

I have been getting good consistent results for the main peaks in terms of frequency but virtually no info on the other expected resonances. See second figure. Reading the threads I suddenly latched on to Trevor's remark about log scales and I realised I had not set the y scale to log. So see the first pic - it is a one off so a bit noisy but shows much more information on the other resonances.

Hope this is useful to others starting out with this apparently straightforward but in practice somewhat tricky area.

Dave

[Dave M]

I was getting fed up with VA on my laptop (Windows7) refusing to save settings whereas the same version of VA on my other machine (Win8) would so I did a bit more digging.

I suspected it was either trying to write it in the wrong place or it was a permissions thing.
So...

By setting the security on the folder in which VA sits, in the case of Win 8 C:programfiles/VA2011, in Win7 C:programfiles(x86)/VA2011 such that users had write access as well as system and admin then VA would save the settings. It seems to write them into a file called VA.INI.

This was more than just a nuisance as it was easy to forget to set it all up properly each time of use. Note you may have the VA files sitting in another folder.

If dealing with files and folders etc isn't your thing find an old style computer geezer like me to help out!

Cheers

[johnparchem]

I just reinstalled a version of visual analyzer and thought I would post what I had to do to get it to launch without errors.

After running the setup exe in the file explorer in C:\Program Files (x86) I changed the properties of the folder visual analyzer -> security tab -> Users -> to full control. This allows me to save alternate configuration files in this location.

In the folder C:\Program Files (x86)\Visual Analyser I changed the properties of the file VA.ini -> security tab -> Users -> to full control. This lets me change and save the ini file without running as administrator.

I was getting an out of range error on startup. I was able to click OK and move on but I hated it. So I opened va.ini in notepad and made ToFreq=5512 (it was set to 20000) I am not sure what this is but I noticed all the freq settings were at a max of 5512 and the error message said 5512 was the max. ToFreq was the only setting I found regarding frequency that was higher.

Now it works without issue.

[Trevor Gore]

Also check out this thread: http://www.anzlf.com/viewtopic.php?f=1&t=7961&p=86157