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Spectrum analyser Equalizer project how to go about it?

Delta Prime

Jul 29, 2020
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Yes. I'm on Post 113. Thank you for asking. The more you ask the longer it's going to take. And because I have to respond. I don't want to leave you hanging. I'm not retired I tried to help where I can but I'm normally doing something else and I got a stupid little phone it doesn't like to cooperate patience my little Padawan forgive the grammar on my speech to text sit boy sit oops I think it heard me
 

Maglatron

Jul 12, 2023
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correct me if I'm wrong! first of all I have settled on 16 columns and 20 rows 320 LED matrix common cathode for the columns and common anode for the rows!
I know that multiplexing lights up one LED in a row at a time and one after another, an LM3914 or LM3916 is a dot bar display driver and can be cascaded, and it's signal is a varying voltage.
Narrow (Single Frequency) Band Pass filter lets a signal pass through and that drives audio filters built around a simple op-amp, Whilst you CAN make analogue filters with VERY narrow pass bands they become increasing complicated and component-dense, but with a digital filter you can derive practically any band width just by programming.
The 3914 is a is voltage peak detector and, all we need to do is get a operational amplifier and a microphone/input, (I want the signals from RCA jacks!) I want to use a splitter cable so that the audio can go into the spectrum analyser and to the midi box that I have.
The FFTlibrary (Fast Fourier Transform) does this digitally and has so called frequency bins, I want 16.
The LED's I'm driving are of the bar graph type, If you increase the number of bands, the overlap will be worse. I can use an alternative way of doing this with the CY8CKIT-059 somehow, but that looks complex.
From what frequency range will light up a certain column and where it overlaps to the next - I want not much overlap so that the output is more crisp.
I am not using WS2812B, So are you constrained to LEDs? yes no LCD's!
OpAmp solutions have problems with accuracy and drift, whereas if a FFT is run its clock accuracy accurate. And basically code based.
The processor can generate effectively all the filters needed because thats what a FFT does, gives you freq versus amplitude as output data.
The challenge in an FFT is update rate because its computationally intensive in processor speed needed.
Difference between filter and FFT : Filter we need a filter solution for each channel (frequency) and can only do 2 / PSOC
chip.
FFT we take a bunch of samples, then run the FFT analysis on the sample set, Its computationally intensive, large latency = lower update rate of display, but I think doable. This is a test you would clearly work out, resolution of FFT in frequency versus update rate, its a tradeoff.
I am not expert here learning myself, I think preferred method here is FFT by far I'll have to make use of transistors aswell.
The difference here is that the FFT takes a number of samples (e.g. 1024) and computes the spectrum from these samples whereas the filters work all in parallel and you get an updated output with every sample.
Thus FFT involves a certain latency (aka delay) between the input and the output of the FFT whereas the filter approach works (almost) instantaneously. When you change the number of bands, you also have to change the center frequency and the bandwidth of each band. This requires a lot of computation and a lot of changing of components
1)So you create an array whose size is a replication of your desired frequency resolution,
and then write a routine to start an Analog to digital and fill that array.
2) Once filled you run the FFT code on that which creates an array where each ROW is
the frequency and two elements in the array, for that row, are real and imaginary magnitude
of the FFT computeted spectra complex magnitude
3) Then you code a routine to take each pair of elements and do the sqrt(sum of squares)
to convert to magnitude and save that.
4) Next you scan array by ROW and convert that MAGNITUDE to a LED value, how many
to turn on. Save that in an array.
5) Now you code the LED scan taking the Array values just computed and turn on GPIO pins
to set the correct number LEDs in that column.

This was an idea
I am going to have a esp32. I want to build a Led matrix of 320 leds 16bands/columns/channels and 20 rows. I will be using 74HC595's, 2 for the columns (thats 20) and 2 for each row there are 20 rows, the columns are updated each 60hz so across the set of 16 there will be 960 pulses of the column cycling frequency and updating the amplitude (how many led's it lights in the y direction) and each bar is represented by 3 decibals. 25 times per second for each band. I am using two RCA jacks (white and red) I do not want arduino code at this point . are you following so far. Frequency Band Analysis: This could be done using an FFT I need to calculate the amplitude of each band I want the bands on the left to be low and basey 32hz and the high pitch to be 16khz
  1. 53.8 Hz
  2. 69.8 Hz
  3. 117 Hz
  4. 151 Hz
  5. 196 Hz
  6. 328 Hz
  7. 721 Hz
    1186 Hz
  8. 1532 Hz
  9. 2559 Hz
  10. 3306 Hz
  11. 4265 Hz
  12. 5489 Hz
  13. 8050 Hz
  14. 11631 Hz
  15. 14955 Hz
I want the high of the bars to be moved up in decibels of 3, for each LED in the column
I was thinking that maybe I should use the LM3914 and the pwm pins of the esp32 dev board (there are 16) each pin to represent a column and band width and set the max signal of the LM3914 to 5V so that means that when the signal is at 5v, all the LED's in that column would light.
I must itterate that I'm not using WS2812B LED strip
anybody have any ideas about charlieplexing and multiplexing with the esp32 and the 20 pins I need for the 320 LED's I'm using in my LED matrix which I'm making
Shift register a I kind of understand but don' know how to implement
thats all the info from this thread condenced!

 
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Maglatron

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this is the actual final settlement size
 

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Delta Prime

Jul 29, 2020
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Below is in LF 353 dual operational amplifier you also notice an electric microphone and associated circuitry
20231112_124424.jpg

Photo below is one LM 3914
20231112_123440.jpg
Photo below is three 3914
The bottom shiny thing is not an LED it's that Mic reflecting The flash it doesn't have that felt that goes over the microphone
20231112_122858.jpg
What you don't see is the matrix cuz I had to dig this up from my camera can't find it and don't get me started on FFT.Try doing the math then you can speak to me about that! So cool you your jets bro I did all of this when I was prepubescent.
I'm on to speak to text thank goodness it left out the profanity.
 

Maglatron

Jul 12, 2023
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OK thats some good stuff do you mind a "talk through" whats going on and I shall try to reverse engineer to LTSpice. and now I know that you know exactly what I'm after thanks for the visual
no idea what "So cool you your jets bro" means but thank you wiring diagram?
what frequency in Hz was your cicuit set for in your band pas filter
looks like something I would have made\!
 
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Delta Prime

Jul 29, 2020
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So cool you your jets bro" means
It means " I suggest you relax".
Is another one for you! " you talk to talk but you don't walk the walk".
This is what that means below
are you following so far
Whilst you CAN make analogue filters with VERY narrow pass bands they become increasing complicated and component-dense,
That's not the only thing that's dense.
OK thats some good stuff do you mind a "talk through" whats going on
My plan is to give you everything on a silver platter! But you keep on interrupting me by having me respond. So...
zipper.png
And let me get to work!!!
 

danadak

Feb 19, 2021
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PSOC 4 64 point FFT done in < 700 uS, and thats a low end part. I believe this
was not done with the single cycle 32 bit multiplier that is also on the chip.
Eg. could have been much faster. 64 point FFT yields 32 frequencies. SAR being
used can produce up to 138K SPS, although the 700 us was done with it at
10K SPS. It was just an example. SAR is 12 bits.


The CY8CKIT-059 board is a simple board, with a snap off programmer/debugger
on end of board.Buit it uses a higher ended PSOC 5LP part. That board costs less
than the PSOC 4 board. But your I/O matrix needs more I/O than that board offers.
So this board more appropriate :


As an aside with a 32 bit single cycle multiplier one could consider doing this with
IIR filter code to create the equivalent of a two pole active opamp filter. So mux that
architecture (below, its code and variable storage) to create the 16 bands. One more
option, but FFT I think is easiest most flexible.

1699835049212.png

Regards, Dana.
 
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kellys_eye

Jun 25, 2010
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On the KISS principal I still think keeping it analogue is the way to go. Sure, try doing it in code and spend weeks/months getting it right and frustration at not being able to identify the problems..... coding a filter? then coding charlieplex of whatever.....???

A quick internet search for digital audio filter brought up this:

8 of which (in their dual package form) resolve the filter issue and the LM3915/6 does the display. Job done.

Now that IC I reference isn't 'mainstream' but that's the result of a first search and choosing the first result - YMMV.
 

Maglatron

Jul 12, 2023
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So cool you your jets bro

So cool you your jets bro

On the KISS principal I still think keeping it analogue is the way to go. Sure, try doing it in code and spend weeks/months getting it right and frustration at not being able to identify the problems..... coding a filter? then coding charlieplex of whatever.....???

A quick internet search for digital audio filter brought up this:

8 of which (in their dual package form) resolve the filter issue and the LM3915/6 does the display. Job done.

Now that IC I reference isn't 'mainstream' but that's the result of a first search and choosing the first result - YMMV.
I shall take that onboard!

On the KISS principal I still think keeping it analogue is the way to go. Sure, try doing it in code and spend weeks/months getting it right and frustration at not being able to identify the problems..... coding a filter? then coding charlieplex of whatever.....???

A quick internet search for digital audio filter brought up this:

8 of which (in their dual package form) resolve the filter issue and the LM3915/6 does the display. Job done.

Now that IC I reference isn't 'mainstream' but that's the result of a first search and choosing the first result - YMMV.
I cannot find anywhere to buy these

MSRAAF​

Resistor Programmable Active Audio Filter​


Kellys Eye
what's all this stuff about "order" google sponsored results analog devices universal filter active filter "2nd order", "5th order"?. Is that what I need?
Is the following special

Resistor Programmable Active Audio Filter​

because I can't find the chips anywhere but that site you provided


Anyway I'm Keeping zipped for the minute! and I'm just going to wait
 

kellys_eye

Jun 25, 2010
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I cannot find anywhere to buy these

MSRAAF​

Resistor Programmable Active Audio Filter​


The link to their products is right there on the age I gave - clue..... the button marked 'sales'.
 

Maglatron

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I know, there is no pricing so I was looking for a generic chip I rang the man based in England he said to get in touch to discuss pricing, what I'm wondering is what would you pay per chip maximum 16 pin dip packages
 

kellys_eye

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what I'm wondering is what would you pay per chip maximum 16 pin dip packages
What's my valuation got to do with it? Right now I'd pay 1p per unit just for curiosity value! But you missed the point of that post anyway - that device was only the FIRST that came up. There are likely to be many more, if not identical to that one then something else offering the same functionality but in a different way, who knows? Have you even bothered to look?

I'm wondering if you'll ever get this project started let alone completed. If you want to be led-by-the-hand for every idea, every purchase, every application, every option etc I think you're barking up the wrong tree.

It's time you did some of your own work and came back to us with any 'issues' you come across in the process.

There has been more than enough options and solutions offered in the last 14 pages - time for you to make your mind up.

Last hint/tip from me https://tools.analog.com/en/filterwizard/
 

Delta Prime

Jul 29, 2020
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I never said that!
I can't even quote that it doesn't show up. You added that.
In any case I should take my own advice. Good luck to you.
1699997382663.png
 

Maglatron

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sorry no disrespect meant I just meant that I'll wait patiently and keep it zipped whilst you do your thing!
My plan is to give you everything on a silver platter!
I said is the plan still to help seriously man no disrespect meant

and i wanted to say is that still the plan but changed it by editing

please don't take it the wrong way I appreciate you and what you are doing to help sorry man

seriously I want and need that help I was just getting along here

I did not mean to offend
 

Delta Prime

Jul 29, 2020
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sorry no disrespect meant I just meant that I'll wait patiently and keep it zipped whilst you do your thing!

I said is the plan still to help seriously man no disrespect meant
No don't worry about it you're correct I hurt your feelings and that was not my intention I was in the wrong to do such a thing.
You did not disrespect me respect is earned not given.
But I must work on my common courtesy please forgive me. Again good luck to you I'm out of here
 

Maglatron

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no way wires crossed man

look I really need your help because you have the ability to and I did not mean anything malicous or narky of off key or disrespectfull I was going to say Is that still your plan then deleted it and wrote nevermind zipped because i didn't want to ask more questions when you said to cool my jets please understand the fault that happend because I think your a cool guy and I'm happy to have the help honestly you did not hurt my feeling |I edited my message because I didnt want you to think I was rushing you sorry for the miscommunication

"you dont bite the hand that feeds you"
 

Maglatron

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No don't worry about it you're correct I hurt your feelings and that was not my intention I was in the wrong to do such a thing.
You did not disrespect me respect is earned not given.
But I must work on my common courtesy please forgive me. Again good luck to you I'm out of here
still recon you can't help?
 

Maglatron

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I did a quick sum and if all the LED's were lit at once it would draw 6.4 amps! I want to use a lithium ion battery 12v along with 7809 regulators, can I do this if I use more that one regulator, each one supports 1.5 amps so if I used 5 of them, what do you recon?
 

Martaine2005

May 12, 2015
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Mux is your aim here.
Only one LED is lit at a frequency that the human eye can’t see. It appears that lots are (on, lit).
So mA’s is more like the current consumption.

Martin
 
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