sound comparison HVC-07 vs HVC-06

Started by FAMICOM_87, October 19, 2019, 09:51:53 am

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Wow, the difference on MM1/2 is stark.

Was Googling to find more explanation about the differences and found this thread from FW:



It was a good watch, even if I couldn't detect much of a difference between them :D
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October 29, 2019, 07:19:24 pm #3 Last Edit: October 29, 2019, 07:25:39 pm by Miklo
It's nothing new.

There's quite a difference in my opinion. You can hear it on the Fireman stage in Rockman in that video link.

If you happen to have FCEUX you can turn down the "noise" channel in the sound config to replicate a HVC-06.

You can compare and contrast a lot of games by turning it up and down. It's quite noticeable.

Sometimes I find the added noise can be annoying for me on certain games...Ironically, the Fireman stage by example.

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Rather than HVC-06 vs HVC-07, I think it's a CPU revision E vs pre-E CPU, as I don't think a HVC-06 is a guarantee that it doesn't have a revision E CPU.
Pre-E versions simply doesn't have the noise mode flag that enables that tonal noise from Fireman's stage. You can simulate the pre-E versions in the emulator Mesen by checking the "Disable noise channel mode flag" in the audio options. I made Noisy so that you can easily test the noise channel in either mode (using an image of an actual flag :)) on your Famicom or emulator. If you set pitch to 0E or 0F you will probably not hear much of a difference when you change the flag. Setting it to any value between 01 and 0D should make the difference extremely clear though.
I also made an NSF (in the attachment of this post) if you simply want to listen to all noise frequencies once with the flag OFF and once with it ON.

I can't find the option to simulate a pre-E CPU in FCEUX (v2.2.3) though? You can turn up and down the noise volume but that is unrelated to the noise mode. Use Mesen to test it.
You don't have to be an audiophile to hear the difference. It's a matter of a tonal beep vs a non-tonal buzz.

Technical explanation:
The noise channel produces noise by using a hardware RNG to generate a random waveform. When the mode flag is OFF, this waveform is longer before it loops which sounds like that toneless noise (AKA "white noise" or "long period noise") used for drums or explosions and the like. If the mode flag is ON however, the looping waveform is shortened down so that it produces a tone on most frequencies. This is called "looped noise", "periodic noise" or "short period noise".

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Here is another video which demonstrates this issue :

In my reply in the comment section I try to explain the difference between the noise modes in a non-technical way.
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Yeah that's a good explanation,"shhh" or "tink". When the flag is OFF the noise will sound like "shhh" and when it is ON it will sound like "tink". On the old APU the flag setting doesn't matter and the noise will always sound like "shhh". Simple as that.