Hi to all!
I want to build an audio graphic analyzer on 10, 20, 30 bands with individual bandpass filters and vu meters.
I have searched with google but the results were very poor.
If anybody have the schematic, links for this please post it here
- What is the best choice for a cheap vu-meter ? I want to make more then 20 vu meters and if I choose LM3915 I have to pay a lot ...
Also I want schematics or links ..
Please help
I want to build an audio graphic analyzer on 10, 20, 30 bands with individual bandpass filters and vu meters.
I have searched with google but the results were very poor.
If anybody have the schematic, links for this please post it here
- What is the best choice for a cheap vu-meter ? I want to make more then 20 vu meters and if I choose LM3915 I have to pay a lot ...
Also I want schematics or links ..
Please help
There was a project in the american magazine Popular Electronics around 1977 for a 10 band RTA. It used a single LM3915 to drive a multiplexed display, and op-amp bandpass filters for each band. I'm slowly building one. Email me and I might be able to scan the article.
I think Rohm has some chips for equalizers and displays, alrhough from what I remember they were more like 5 bands for ghetto blasters and low-fi systems. They might also have some bar graph drivers that are cheaper than the old National Semi parts.
Alternatively, use an old PC with a sound card and run some RTA software. Scrounge a video card with TV-out and you can watch it on your TV. A pentium should be fast enough.
Or, cruise the pawnshops and there's a good chance you'll find an old graphic equalizer with a built-in RTA, for not much money.
I think Rohm has some chips for equalizers and displays, alrhough from what I remember they were more like 5 bands for ghetto blasters and low-fi systems. They might also have some bar graph drivers that are cheaper than the old National Semi parts.
Alternatively, use an old PC with a sound card and run some RTA software. Scrounge a video card with TV-out and you can watch it on your TV. A pentium should be fast enough.
Or, cruise the pawnshops and there's a good chance you'll find an old graphic equalizer with a built-in RTA, for not much money.
I was wonder if anyone knows how to make a 10x10 matrix (LEDs) VU spectrum analyzer with the help of the printer parallel port.
It can be useful for those who desire a fancy audio "visual"
I saw a schematic for 16x16 matrix but the i don't know how to start it because it does not mention anything about software.
Adrian,
It can be useful for those who desire a fancy audio "visual"
I saw a schematic for 16x16 matrix but the i don't know how to start it because it does not mention anything about software.
Adrian,
Adrian,
In May of 2004, Dr. Dobbs magazine published an article explaining how to convert a Nintendo Gameboy into a spectrum analyzer. The cost at the time was around US $70.
Maybe that is an affordable alternative to what you want to do.
In May of 2004, Dr. Dobbs magazine published an article explaining how to convert a Nintendo Gameboy into a spectrum analyzer. The cost at the time was around US $70.
Maybe that is an affordable alternative to what you want to do.
The article is available on-line and I think you can get a six months limited access membership at no cost. You can find it here:
http://www.ddj.com/documents/s=9132/ddj0405p/0405p.htm
http://www.ddj.com/documents/s=9132/ddj0405p/0405p.htm
adrianbodor said:Hi to all!
I want to build an audio graphic analyzer on 10, 20, 30 bands with individual bandpass filters and vu meters.
I have searched with google but the results were very poor.
If anybody have the schematic, links for this please post it here
- What is the best choice for a cheap vu-meter ? I want to make more then 20 vu meters and if I choose LM3915 I have to pay a lot ...
Also I want schematics or links ..
Please help
Here's a much easier way to do it (than driving yourself crazy building dozens of bp filters) -- get yourself a Zetex ZFX36L01 chip -- it can do bandpass and notch with adjustable Q -- and it can be swept !!!
use a clock to periodically sample and hold the signal -- you can generate the sweep with a couple CMOS logic chip -- or if you want to use the serial port on your computer you can write the appropriate code.
there are some advantages to using analog vs FFT
Attachments
Re: ZFX36L01
Yupp, they don't even list it in their catalog of obsolete products -- you could replicate the device with an analog devices mixer and VCO -- I would use a crystal filter rather than an analog filter, however.
btw, Zetex did send me an evaluation board and a couple of chips but this must have been 5 years ago.
ppcblaster said:
Yupp, they don't even list it in their catalog of obsolete products -- you could replicate the device with an analog devices mixer and VCO -- I would use a crystal filter rather than an analog filter, however.
btw, Zetex did send me an evaluation board and a couple of chips but this must have been 5 years ago.
ZXF36L01
ZXF36L01 A search came up Empty no good, If you have a sourse please post.
Thank You.........
jackinnj said:
ZXF36L01 A search came up Empty no good, If you have a sourse please post.
Thank You.........
While thinking about the swept filter + sample and hold, I see an inherent problem. It has to do with display update rate. At the lower frequencies in the band, it will require a good length of time to get a good sample. Consider at least one period for each frequency (at 20Hz would be 50ms..and so in in whatever octave resolution you desire. By the time the full audio spectrum is swept, it may have been 400ms or so (just guessing here). That is a very low update rate for a VU meter, I believe it would not be tolerable.
jackinnj
Could you please post a schem and the parts and data, sweep,
to build a Bass and Treb control.
Thank You
Could you please post a schem and the parts and data, sweep,
to build a Bass and Treb control.
Thank You
I'm pretty sure that the Zetex product is obsolete --this chip isn't for that purpose. check other threads.
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