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Comment by jchw | Hacker News Reader

Huh, is it really true this is the first? I figured this was just being done in hardware in some modern laptops instead of software. At least for basic stuff like EQ, if not compressor/etc. Otherwise, what's with all of the DSP stuff modern Intel laptops need on Linux, what with Sound Open Firmware and whatnot?

(And if not that, I am mildly surprised ChromeOS/Chromebooks don't do much of this either.)

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TL;DR various variants of the same technique are covered by different patents, and Apple doing this on application processor avoids some of those patents.

A good example of different approach is laptops branded with "Harman Kardon" speakers - Harman-Kardon has a patent on exactly this but involving separate DSP running transparently to the OS. Similarly there are various other solutions to improve sound quality of small speakers being done, and for some of that modern SoCs are bringing in dedicated DSPs onboard.

Man patents were a mistake. “Run DSP on a separate chip” should not be remotely close to the realm of things which the state creates a legal monopoly for.

Interesting. So, on top of, I presume, whatever DSP you get from the sound chipset/SoC, there could be other layers of DSP throughout the hardware too. That seems like a real pain in the ass, to be honest. (Though personally I'd really prefer something that protects the voice coils from overheating to be in hardware at least, if nothing else.)

(I still do genuinely wonder what's going on inside of SOF on modern Intel laptops, too. That's not separate from the chipset and I don't think it gets tuned for specific laptop acoustics. So what does that do?)

I think modern Intel chips contain Tensilica Xtensa HiFi DSP [0] cores for audio processing, I’m pretty sure this is what SOF targets.

I’m not an expert, but probably used for speaker DSP as well as mic/speech processing (think for Cortana/etc).

Manufacturers of laptops probably provide their own firmware to load onto these cores as part of a driver.

[0] https://www.cadence.com/en_US/home/tools/ip/tensilica-ip/hif...

Phoenix APU presentation talk about DSP for dropping processing into input/output of audio (quite probably including things like turning an array of microphones into single source, etc.)

Having recently looked for new laptop, they often have firmware loaded by driver on windows into DSP or sound chain, sometimes even to enable half of the speakers you need to custom load firmware on Linux which apparently includes DSP code that adapts stereo signal for multiple speakers with different parameters.

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