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How to measure frecuency response and wow & flutter?

walkman.archive - 2011-02-09 10:06

I think this is a question for the experts.



I'd like to measure all this parameters for some of my walkmans, to have a better idea of how they score. I know that to measure freq. response I have to use an oscilloscope, so what I belive I have to do is (please correct me if I'm wrong):



1) Generate a sine variable frecuency going from 20 to 20.000 Hz, at XX dB, using my sound card, previously calibrated with TrueRTA software.



2) Record that with a good recorder. I plan to use my D6C, with perfectly cleaned head and rollers and a new Maxell XL-II S (which has been calibrated to), but, which record level do I have to use? I believe the LEDs on the D6C are acurate, but if you are in dim light, when one is OFF, and the one closer to it is ON seems to affect the first one with some unwanted light, and I'm not sure if the first one is in a low light mode or if it is light from the other LED close to it. This problem takes me to another question: ¿how do I *exactly* find the optimun record level with a D6C?



3) Let's assume I have that "reference tape". Now I put it in the desired walkman and play it. Adjust the volume to a defined level, which I don't know which one is.



4) Disable Dolby? Disable MegaBass/DSL?



5) Read this variable frecuency with TrueRTA to build the complete curve

6) I have absolutely no idea if I can read wow& flutter with my equipment. Does TrueRTA have any function for that? I remember someone talked about another oscilloscopy software some time ago, and posted pics, but I din't remember which one was that soft.



And that's all, right? Cheers,



Hugo

intell2000 - 2011-02-09 14:54

Hello hurodal.

To measure freq response correctly better to get a good test cassette for this purpose.

To measure wow & flutter on your PC you can get software form this page (use google translator to read Russian):



http://www.vegalab.ru/forum/showthread.php/41262-Wow-and-flutter-програмный-измеритель-детонации.



Sorry for my poor english.

thelion - 2011-02-10 18:31

Hey Hugo,
I believe your answers lay in the service manual of each model.
forgive me for my curiosity, but why do you want to go there, measure each Walkman for technical stuff (and I guess there are many of them)? what benefit will you get out of that info.
Cheers
TheLion



Aiwa Rules, Sound, Design, Style, Sexy.......

walkman.archive - 2011-02-11 00:38

Hi intell2000,

Thanks so much for your info.
I've downloaded it, and I'll test it as soon as possible.


Dear TheLion,

Oh, I understand. Well, I'm not planning to start doing as a technician ;-)
It's only curiosity. I'd like to have realistic measures to learn some tech things, like, "how much does the improves when azimuth is properly adjusted?" and similar questions.

Regards,

intell2000 - 2011-02-11 07:10

Originally Posted by hurodal:


       


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        Hi intell2000,

Thanks so much for your info.
I've downloaded it, and I'll test it as soon as possible.








For correct results you need good test tapes, they can be found on Ebay.

for example:



http://shop.ebay.com/coollpe/m.html



walkman.archive - 2011-02-17 12:30

Thanks for the advise!!