Author Topic: Analysis of VRC6 volume  (Read 29342 times)

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Offline Slamy

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Re: Analysis of VRC6 volume
« Reply #30 on: March 16, 2018, 12:29 AM »
The VRC6 mapper can control only the Pins of the FPGA and so only the external sound chip. So, yes.
You've mentioned "thinking noise". The Firmware of the Everdrive has a Bug which probably never gets fixed: If a mapper without external sound hardware is used the '"thinking noise" is louder.
I assume this is because the pin is floating in that case. I don't have proof for this theory but this is the reason why I have also a switch at my NES to cut the external sound connection connection. The noise is reduced that way with normal games.

Offline James-F

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Re: Analysis of VRC6 volume
« Reply #31 on: March 16, 2018, 07:36 AM »
Unlike the NES that has its internal audio go directly to the output RCA jack and the resistor mod that mixes in parallel to the original audio path, the AV Famicom internal audio is looped back from pin 45 to pin 46 and has to be bridged inside the N8 or any other cartridge so it is mixed in series, hence I don't think the N8 leaves anything floating, else there will be no audio on the Famicom.

I can actually hear a click/pop when loading the Akumaou Densetsu or Mr. Gimmic roms, or resetting the console after it, but not with other games that don't use external audio.
I assume it is the 'relay' changing the audio path when loading external audio games.

The thinking noise I was talking about is normal on most consoles with analog audio path when the TV volume is raised way high, some have it more than others.
On a second listening I was actually wrong, the thinking noise happens only when the N8 loads a rom with the TV volume high, inside a game the SNR is good and comparable to any other cartridge even when the TV volume is high.
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Offline Kwyjibo

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Re: Analysis of VRC6 volume
« Reply #32 on: March 17, 2018, 10:20 AM »
I did the extra audio mod tonight and immediately noticed all the new backgrounds noises.  The ED menu itself is very noisy.  I don't feel like installing a toggle on my NES so I just used a 100k ohm resistor instead of the 47k I first installed.  That makes it tolerable without messing up the mix.

Offline brianvgplayer

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Re: Analysis of VRC6 volume
« Reply #33 on: March 20, 2018, 06:25 AM »
Thank you very much Slamy!
After a careful recording and volume matching in Sonar (my DAW), my result is that 35_35 is most accurate with the AV Famicom and EDN8-Fami.

One thing though, the overall volume is quieter than other non VRC6 games, can it be boosted?

I tried it and the actual cart on the AVS and 35_35 is too quiet for me.

Offline James-F

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Re: Analysis of VRC6 volume
« Reply #34 on: March 20, 2018, 06:32 AM »
The AVS and the AV Famicom are imbalanced with original cartridge, they have the internal volume much too quiet compared to the real external VRC6.
The original Akumajou Densetsu cartridge sounds right only on the original Famicom or Analogue NT.
The 35_35 file will make the N8 on an AV Famicom sound like the original Cart on the original Famicom, NOT like the original cart on the AV Famicom or AVS which is indeed imbalanced.
I do not have the AVS and do not know what volume file will be right for it, again, the 35_35 file is only correct for the AV Famicom.

In this video you can hear the original AD cartridge on the Analogue NT with correct balance, and AVS with incorrect balance (too loud VRC6).
https://www.youtube.com/watch?v=wlw1NC57FLU
« Last Edit: March 20, 2018, 07:40 AM by James-F »
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Offline brianvgplayer

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Re: Analysis of VRC6 volume
« Reply #35 on: March 20, 2018, 08:06 PM »
I'll see how it sounds on my AV famicom, which is a bit louder than the AVS, but I tried lower volumes around that area on AV Famicom before and thought they sounded too low, even in comparison to the sound in that video.

Offline James-F

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Re: Analysis of VRC6 volume
« Reply #36 on: March 20, 2018, 08:07 PM »
What is your reference hardware/recording?
Too low compared to what?

You have to listen to the balance with the same speakers/setup as your reference recording.
I used Behringer B3030A studio monitors (top notch audio quality and discontinued for legal issues) and calibrated room modes for flat frequency response in the room at the listening sweet spot, and Audio Technical ATH-M40X headphones which have flat frequency response and reference quality.
Using Sonar DAW I flipped between the recordings of 50,45,40,35,30 VRC6 and compared to the recording of Analog NT, Famicom and Nestopia emulator (same balance on these).
With both my AV Famicoms (CPU-01 and CPU-02), 35 VRC6 sounds the closest to the reference recordings mentioned above.
*EDN8-Famicom with OS16.

I suggest doing the same for your AVS if you have good ear (I'm a musician) and proper equipment.
« Last Edit: March 20, 2018, 08:35 PM by James-F »
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Offline brianvgplayer

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Re: Analysis of VRC6 volume
« Reply #37 on: March 20, 2018, 08:35 PM »
It was actually a long time ago when I tried the lower volume and don't even remember if I tried 35. I tried 35_35 on the AV Famicom and you were right. It sounds excellent on the AV Famicom. I think I'll keep the sound at one of the high volume ones since that mix sounds terrible on the AVS. I wish the Everdrive still had the Hi-Lo option. 
« Last Edit: March 20, 2018, 08:39 PM by brianvgplayer »

Offline James-F

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Re: Analysis of VRC6 volume
« Reply #38 on: March 20, 2018, 08:38 PM »
;)
Yeah, volume 35 is a new addition since this month 03.2018 to the VRC6 files by Slamy.
Mind you, I don't own any other version of the NES, so I can vouch only for the AV Famicom.

I can help you find the correct volume for your AVS with the N8, if you provide 5 seconds of the beginning of the "Beginning" track from AK for each volume mapper (100-30).
BUT, if you have custom resistors in the 72-60 adapter, the results will be ONLY for your setup, since people have difference resistors in different places for the NES.

EDIT:
The AVS has an "Exp Volume" slider so just use that to find the correct balance.
« Last Edit: March 20, 2018, 09:08 PM by James-F »
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Offline Slamy

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Re: Analysis of VRC6 volume
« Reply #39 on: March 20, 2018, 11:32 PM »
I've found a more technical way to check the volume. Today I started to learn NES assembly. I'll try to develop a program which alternates a pulse wave on the VRC6 and the APU. The volume should be identical. At least this is the plan so we can finally have peace. This approach could also be done without knowledge of Audio analysis.

Offline Slamy

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Re: Analysis of VRC6 volume
« Reply #40 on: March 25, 2018, 06:45 PM »
I don't know if this is helpful. But here you go.

You can also read the source code and compile it by yourself.
https://github.com/Slamy/vrc6test

Offline James-F

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Re: Analysis of VRC6 volume
« Reply #41 on: March 25, 2018, 10:47 PM »
Fantastic work!
Very useful tool indeed!

Although I think the VRC6 should be slightly quieter than APU for correct balance as I find if they have exactly the same volume, the resulting VRC6 sounds are louder than they should be and drum sounds in AD drowned by the bass sound from the VRC6.
« Last Edit: March 26, 2018, 06:23 AM by James-F »
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Offline Arnold101

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Re: Analysis of VRC6 volume
« Reply #42 on: May 16, 2018, 04:36 AM »
I don't know if this is helpful. But here you go.

You can also read the source code and compile it by yourself.
https://github.com/Slamy/vrc6test
vrc7 and sunsoft exp audio can be boosted too? now without the HI function on the edn8 is a mess  on the famicom :(
for example after trying your tool, the apu volume is exactly twice the vrc6 with os v20 b2..... and with the vrc6mod!
« Last Edit: May 16, 2018, 05:01 AM by Arnold101 »

Offline James-F

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Re: Analysis of VRC6 volume
« Reply #43 on: May 16, 2018, 09:04 AM »
I have attached my AV Famicom recording with Slamy's VRC6 mapper on N8 v20-beta2.
Beginning

The result is very accurate balance in comparison to these official reference recordings:

https://www.youtube.com/watch?v=ptgaCJSF7j8
https://www.youtube.com/watch?v=wlw1NC57FLU (Analogue NT + original cartridge).
https://downloads.khinsider.com/game-soundtracks/album/akumajou-densetsu-nes/03%2520-%2520Beginning%2520%2528Block-1%2529.mp3
« Last Edit: May 16, 2018, 09:23 AM by James-F »
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Offline James-F

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Re: Analysis of VRC6 volume
« Reply #44 on: May 16, 2018, 02:52 PM »
I traced and made a schematic for the AV Famicom audio rout.
*after images my findings.





I added a 500k trimpot in series with the 68k resistor to boost the AV Famicom volume to match the original famicom.
The result is with full 560k resistance there is distortion present (U3 internal op-amp is clipping) while boosting the overall audio by 7db+distortion.
That means the AV Famicom output amplifier is already maximized by the engineers right before clipping but does not clip with stock resistor.
edit: the original famicom clips the waveform before it reaches the cartridge, or the RF modulator.


http://nerdlypleasures.blogspot.co.il/2016/09/famciom-vs-av-famicom-external-internal.html
This is a blog post by Great Hierophant that points out that the difference between internal OG Famicom and AV Famicom is NOT that big and I measured only 1db difference from his 240p suite sine tones recordings.

That means practically all complaints about volume is NOT about balance but the combined (int+ext) volume of special mapper games on the N8.

EDIT:
Ah, here is something everybody should know before complaining about sound balance.
The Original Famicom is actually clipping its internal signal BEFORE it even reaches the cartridge.
This is just a zoom in on the wave forms from Nerdly Pleasures site I linked.
« Last Edit: May 16, 2018, 04:14 PM by James-F »
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