DSP basics and FIR Filtering

[MichaelEA]

I often see questions asking for more information about FIR filtering and the pros and cons. I've put together an article describing some DSP, FIR and IIR basics, and applications in audio.

https://eclipseaudio.com/fir-filter-guide/

Let me know if you find this helpful, and/or if there's anything else you'd like to see included.

BR,
Michael

 

[amirm]

I just glanced at it and it is very comprehensive!

 

[JohnYang1997]

Why is Independent Phase Control Useful?
A loudspeaker driver can be thought of as a minimum-phase filter (when comparing the acoustic output with the electrical signal into the driver). When using minimum-phase EQ to bring a loudspeaker driver’s magnitude response closer to “flat,” the phase of the loudspeaker driver also flattens and moves closer to linear phase (at least within the audible pass-band of the loudspeaker).
However in a typical multi-way loudspeaker, the IIR HP and LP crossover filters (as well as polarity, delay and acoustic filters, like ports) all add frequency-varying extra phase. Because of this extra phase, a multi-way loudspeaker can be thought of as a minimum phase system PLUS some all-pass filters.

This is very important to understand for most people who do eq for headphones/earphones.
Many people think linear phase sounds "very cool" and minimum phase sounds like a loser. But in fact minimum phase could be the most suitable for headphone correction. It also corrects square wave response to almost perfection which was thought to be limited by the driver performance.

VERY NICE!

 

[daftcombo]

This is very important to understand for most people who do eq for headphones/earphones.
Many people think linear phase sounds "very cool" and minimum phase sounds like a loser. But in fact minimum phase could be the most suitable for headphone correction. It also corrects square wave response to almost perfection which was thought to be limited by the driver performance.

VERY NICE!

We have to distinguish
Minimum phase for a speaker
Minimum phase for a correction.
Which did you have in mind?

 

[JohnYang1997]

We have to distinguish
Minimum phase for a speaker
Minimum phase for a correction.
Which did you have in mind?

For single driver frequency response correction. Headphones mostly are single drivers, so are many earphones.

 

[daftcombo]

For single driver frequency response correction. Headphones mostly are single drivers, so are many earphones.

Do you think that a driver sounds better at minimal phase?
My understanding is rather that a correction by EQ at minimal phase also correct the phase to put it linear.

 

[JohnYang1997]

Do you think that a driver sounds better at minimal phase?
My understanding is rather that a correction by EQ at minimal phase also correct the phase to put it linear.

Minimum phase equalization automatically corrects the magnitude response and phase response of the single driver the same time. It's automatically linear after equalization.
For headphones, they will have a target frequency response (mag+phase), due to hrtf. As it's occurred naturally, minimum phase is still preferred.