10 ms·
> - the audio is a bit harsh; it sounds like it needs some filtering, maybe just some dead simple high-pass filter would do it Could you clarify what was meant
by metaphor 10y ago
> - the audio is a bit harsh; it sounds like it needs some filtering, maybe just some dead simple high-pass filter would do it
Could you clarify what was meant by harsh?
The HDMI PHY[1] differentially encodes either I2S or S/PDIF (from SoC). This is a lossless digital-to-digital translation, which suggests that audio being a bit harsh is either a consequence of precise emulation of the NES APU[2] or something wonky with the speakers you're using.
I made the assumption that by harsh you meant dissonant sounds of a relatively high audio frequency, which would make sense given how the 2A03 APU synthesizes audio, but wouldn't make sense if you're suggesting that a dead simple high-pass filter would resolve the issue.
[1] http://www.epmi.com.tw/sayapro03.php?id=78 http://www.epmi.com.tw/sayapro03.php?id=78
[2] https://en.wikipedia.org/wiki/Ricoh_2A03 https://en.wikipedia.org/wiki/Ricoh_2A03
- johansch 10y agoI bailed out halfway into my CS/EE university program (to start working in software instead) a very long time ago in part so I wouldn't have to finish the signal theory/processing course, so please bear with me. "I made the assumption that by harsh you meant dissonant sounds of a relatively high audio frequency" Yes, that's what I'm hearing. Here is a comparison video where you can listen to the difference between the original NES (via an ADC, presumably) and the NES Classic Mini: https://www.youtube.com/watch?v=Z9EyI3mVhi4 https://www.youtube.com/watch?v=Z9EyI3mVhi4 Anyway, to me it sounds that by just filtering away some high frequencies you would get a better approximation of the original. Edit: Oh wait, I see what I did; I mixed up high-pass filter with low-pass filter (again). Doh. I do maintain that whoever named them made a mistake.
- morganvachon 10y agoA sibilance filter would be fairly easy to make, I built a headphone amp board with a sibilance filter circuit in it many years back.
- johansch 10y agoIs that something that can be cheaply done in software (with low latency - like less than 50 ms)?
- nitrogen 10y agoAn IIR low-pass filter can be implemented with a delay measured in tens of microseconds. With regard to naming of high-pass/low-pass filters, it might help to think of the opposite names (low-cut/high-cut). Pass is the opposite of cut/reject.
- morganvachon 10y agoI have no idea as I'm not a programmer, I'm pretty much a hardware/EE guy. When I built mine it was less than 50 cents in discrete components and can definitely be done with SMT components to save space. I don't see why not though; I can get some pretty precise filtering using LADSPA plugins in software mixing apps.
- metaphor 10y agoAhh, makes sense now. The emulator sounds like it does an outstanding job of functionally reproducing the APU, but clearly doesn't capture the analog LPF contributions of the original architecture[1] (2nd and 4th pages apply). An improvement to the NES Classic will necessarily have to come in software as a DSP LPF either within the emulator application or at the OS level (someone mentioned seeing alsa during boot??). Nevertheless, a passive analog hack is definitely not going to be applicable. [1] http://www.freeinfosociety.com/electronics/schemview.php?id=2405 http://www.freeinfosociety.com/electronics/schemview.php?id=...
- kaoD 10y agoNice link! Not only the high end is too crisp, the low end sounds "fatter" too.
- johansch 10y agoThat guy's Youtube channel appears to be full of wonderful things, I just noticed: https://www.youtube.com/user/KM65536/videos https://www.youtube.com/user/KM65536/videos
- jungletek 10y ago>I do maintain that whoever named them made a mistake. Nah, they're named fine, you're just doing the incorrect mental-shortcut that I used to do: because there's 'low' and 'filter', you're ignoring 'pass'. The lows or the highs (respectively) pass-through the filter.