Hi there!
Thank you for clicking on this post.
I have been trying to find a FIR filter (including coefficients ) example ( not create one! ) which is used for audio devices ( such as speakers ), which conform to audio standards ( such as AES17).
Specifics of the type of filter I am looking for: https://www.audiotech.com.tw/AES17 Filter.htm
I've looked at multiple DACs to find an example filter, but to no avail :/
Hope experts like yourself can help me here.
Samster out
Thank you for clicking on this post.
I have been trying to find a FIR filter (including coefficients ) example ( not create one! ) which is used for audio devices ( such as speakers ), which conform to audio standards ( such as AES17).
Specifics of the type of filter I am looking for: https://www.audiotech.com.tw/AES17 Filter.htm
I've looked at multiple DACs to find an example filter, but to no avail :/
Hope experts like yourself can help me here.
Samster out
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This zip folder has a bunch of different FIR filters that I generated in RePhase for my Hypex Fusion amp. I think this is what you're looking for.
They will likely only work in a Hypex Fusion amplifier since they are specifically programmed for that. What are you using for your FIR filtering?
Checked out the filters @ThatSoundsGood. They may work, but I'm still testing it out.
In my case, I just need to model the filters used in DACs (i.e. at the hardware level ) and ensure there is minimal distortion on a variety of audio signals.
The model does include a amplifier, however I believe it's a class D amplifier, not a Hypex Fusion one. Will still check out the freq response of the filter's you've provided, and accordingly check if I need to drop filter coefficients.
I apologize @TNT , I confused FCC for the standards. That was for a entirely different project involving GSM. I've gone and corrected my initial request.
I'm looking at the distortion effect of filters with regards to AES17 standard.
In my case, I just need to model the filters used in DACs (i.e. at the hardware level ) and ensure there is minimal distortion on a variety of audio signals.
The model does include a amplifier, however I believe it's a class D amplifier, not a Hypex Fusion one. Will still check out the freq response of the filter's you've provided, and accordingly check if I need to drop filter coefficients.
I apologize @TNT , I confused FCC for the standards. That was for a entirely different project involving GSM. I've gone and corrected my initial request.
I'm looking at the distortion effect of filters with regards to AES17 standard.
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A DAC has as a part of the product itself a filter that should satisfy the sampling theorem i.e. a very sharp filter at fs/2. Its not a standard, its physics... 🙂 but many dont bother ... go figure...
"S-AES17 is a hardware filtering kit for optional installation in System Two, System Two Cascade or Cascade Plus that satisfies the AES17-1998 specification for a standard low-pass filter for THD+N measurements of digital-to-analog converters (DACs) which exhibit high-level out-of-band noise."
(http://www.audiotech.com.tw/AES17 Filter.htm)
So the filter you are asking about is part of a DAC evaluation standard. It's strange that standards limit what they measure as the product will continue to spew out HF when in use. I dont know why the standard is made like this. Its really not useful in general and serves no other purpose then making poorly designed product look good on the test bench.
Why do you need a FIR version of such filter?
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"S-AES17 is a hardware filtering kit for optional installation in System Two, System Two Cascade or Cascade Plus that satisfies the AES17-1998 specification for a standard low-pass filter for THD+N measurements of digital-to-analog converters (DACs) which exhibit high-level out-of-band noise."
(http://www.audiotech.com.tw/AES17 Filter.htm)
So the filter you are asking about is part of a DAC evaluation standard. It's strange that standards limit what they measure as the product will continue to spew out HF when in use. I dont know why the standard is made like this. Its really not useful in general and serves no other purpose then making poorly designed product look good on the test bench.
Why do you need a FIR version of such filter?
//
@TNT ikr! I'm also worried that having this kind of restriction on the filter measurement should be meaningless. But here we are, 25+ years after they decided to go on this spree.
The reason for having the FIR version ( forgive me if it sounds noob ) is basically having access to the filter coefficients in register form.
I can easily tweak registers in design flow (i.e. at HW level) to potentially change the filter's response in a certain way.
But to get started with, I lack an example filter which is used in audio devices.
The reason for having the FIR version ( forgive me if it sounds noob ) is basically having access to the filter coefficients in register form.
I can easily tweak registers in design flow (i.e. at HW level) to potentially change the filter's response in a certain way.
But to get started with, I lack an example filter which is used in audio devices.
What do you mean by "register form"?
A FIR filter is a representation of impulse response - most of ten in the form a sound file like a .wav file. It is used to convolute the data stream that shall be filtered.
Here is a tool to create FIR filters:
https://rephase.org/
There is also a thread here about the tool.
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A FIR filter is a representation of impulse response - most of ten in the form a sound file like a .wav file. It is used to convolute the data stream that shall be filtered.
Here is a tool to create FIR filters:
https://rephase.org/
There is also a thread here about the tool.
//
@TNT Apologies for the miscommunication.
At hardware level, the filter coefficients are stored in registers aka memory. This I know is the case for DAC's using FIR filters.
I'm not sure how other filters ( such as IIR, analog, etc. ) operate, so my answer may have seemed out of touch.
Thank you for the link! Will check it out.
At hardware level, the filter coefficients are stored in registers aka memory. This I know is the case for DAC's using FIR filters.
I'm not sure how other filters ( such as IIR, analog, etc. ) operate, so my answer may have seemed out of touch.
Thank you for the link! Will check it out.
Hypex Fusion amplifiers are Class D so it's a good match there. There are several different ways to create FIR filters. I recommend getting RePhase to create your own. It's actually pretty easy and the program is free.
https://rephase.org/