Genesis/Megadrive audio comparison recordings. CCAM, stock consoles, mods and more...

[MaxWar]

Comparative audio recordings
of the Genesis/Megadrive consoles.
By MaxWar.

Intro: What are we comparing exactly?
In this thread I will be doing recordings of my Genesis consoles for sound quality comparison purpose. My aim with this is to end speculation and instead compare various consoles and mods with the help of standardized recordings. I initially started this to see how the Crystal Clear Audio Mod board I bought would compare on different genesis revisions. In the end I decided to make a thread that could be updated with whatever genesis related sound comparison experiments I do in the future.

So far we have recordings from stock Model 1 console. Mostly from My recapped VA3, but also a few from a VA6
I have recordings of some stock model 2, mostly VA4, because it is apart from the other model 2.
Most of my recordings though are with the CCAM.
I have made most of my CCAM recordings with the RetroGamer CCAM board, which has a lowpass filter to make it sound closer to a model 1 genesis.
I have compared most CCAM ready consoles with this setup. Namely M1VA7, M2VA1 and M2VA4. I am missing 2 ASIC variants altogether. One from Late model 3 and the one from Nomad.
I have also modified my RetroGamer CCAM board to comply with Tiido's original plan, those are far less filtered and in my opinion show how a CCAM should sound like, Those recordings have the tag - Original - on them.
You will also notice some of the Files have the -YM3438CCAM- label. Those are from a model 1 modified to use the Discrete YM3438 sound chip. This has been found to be just as good as using a model 2 for CCAM purpose. As shown in this blind test study.
http://www.vogons.org/viewtopic.php?f=5&t=36417

About comparative sound recordings: <- You can skip this if not interested in the technicalities.
I like to do sound quality comparisons with recordings, Ive been doing them in the past on various occasions.
Most record based sound comparisons attempts I see are flawed because they use improper and/or inconsistent recording methods and inadequate media. ( I do not consider youtube an adequate media )

Those things are a prerequisite if you want the experiment to yield conclusive data.
I have written a guide about my standardized method for doing comparative recordings. https://sites.google.com/site/soundc...cording-method

Is this method absolute or perfect? I will never claim it is, but It gives a consistent result and aims at capturing the source as is. I can record a console once, then do it 6 months later and the recordings will sound exactly the same.
I will add a couple details that are not in this guide, more specific to recording consoles.

1.Do not record while the console is connected to a live CRT TV. Turn off the CRT before the record or it will induce a characteristic high pitched interference. I learned the hard way as earlier recordings I have made suffer from this.
I have not tested this with LCD screens, It is probably ok but I have not tested and would still turn it off just in case.

2. I use a Behringer HD400 ground loop isolator device for my recordings: Ive pondered if this was a good idea or not as It can help filter out part of the interferences generated on ground level by the source. But I will tell you why I use it and why I think it is a good idea.

-It does not affect the sound signal itself.
-If the source you are recording produces electrical interferences on the signal itself, it will not filter that out.
-It will remove interferences from outside and variable sources and you dont want those. Once the recording is done, those may be mistaken for a problem of the source, which may not be the case.
-Basically it is just one more precaution into making the results more consistent.

*A ground isolator should not be used as an easy fix. It should not be used without first trying to limit interferences in any conventional way ( keep cables short, away from AC lines, turn off nearby noise generating devices like CRT etc.. )

Recordings:

I decided to organize this on a per song basis. I pick up tracks by their ability to reveal key differences or problems in the sound, or simply because they are somewhat classic. This step is arbitrary and I may decide to stop using some tracks or start using some new ones in the future. But I will try to keep some standards. So far I only used original games I own, I have no flash cart anyway.


-Dungeons&Dragons: Warriors of the eternal sun: Valley 1


This is in my opinion one of the best track to make Genesis sound comparison and it is why I place it first. If you should want to download only one series, I recommend this one.

-It shows a good difference between YM2612 and YM3438
-It is great for showing what I believe to be YM2612 DAC artifacts.
-It is a quiet sound track, which means you need to up the input volume more than other games, this is great for comparing background noise levels. Some genesis games will output pretty loud audio, effectively drowning out noise problems.
-It makes good use of PCM drums

DnD-Valley1-M1VA3.flac *This recording has CRT whine noise due to connected CRT.
DnD-Valley1-M1VA6.flac
DnD-Valley1-stock-M2VA3
DnD-Valley1-CCAM-M1VA7.flac
DnD-Valley1-CCAM-M2VA1.flac
DnD-Valley1-CCAM-Original-M2VA1.flac
DnD-Valley1-CCAM-M2VA4.flac
DnD-Valley1-YM3438CCAM-M1VA3.flac
DnD-VALLEY1-YM3438CCAM-Original-M1VA3.flac

Observations:
-I consider the two YM2612 (M1VA3, M1VA6) versions to be practically identical minus the CRT noise on the VA3 one, a mistake on my part. ( its an older recording)
-On the CCAM boards, noise is revealed on the M1VA7 and the M2VA1. I left a split second of silence in the beginning and you can hear the parasites. It is a bit worse on the VA7. By contrast on the M2VA4 noise is extremely low. On the old Model 1, both stock and modified with CCAM, noise is also pretty tame but you still have a constant background hiss that is always there.
- You can notice with the flute that PSG in M2VA4 is a bit weaker.
-This track is interesting to appreciate the difference between YM2612 and YM3438. You can hear some artifacts on the YM2612. Those are caused by the Digital to analog conversion and it seems to actually play a significant role on how this track sounds.

*I personally prefer this track on the original Model 1 with YM2612. Despite, or maybe actually because of the artifacts, The YM2612/model 1 dense and slightly overdriven output plays well with this track by making it sound more "full". By contrast one can appreciate how dry and precise the CCAM is. Everything is cut razor sharp. It affects the PCM drums that I find to blend in less well than with the model 1 YM2612.


-Thunder Force IV : Fighting Back - Stage 1-A



This is a staple of genesis music and also included in one of Tiido's original demo file. Hearing Tiido's recording of this is what initially made me want to get a CCAM. It is also one of the good tracks to compare the relative level of FM vs PSG. Just as the song begins, the fast arpeggio wave line is done with the PSG.


Tiido's original demo.
TFIV-levela1-VA3(postrecap).flac *This recording has CRT whine noise due to connected CRT.
TFIV-level1A-M1VA6.flac
TFIV-level1a-CCAM-M2VA3
TFIV-level1a-CCAM-M1VA7.flac
TFIV-level1A-CCAM-M2VA1.flac
TFIV-level1-CCAM-Original-M2VA1.flac
TFIV-level1A-CCAM-M2VA4.flac
TFIV-Level1A-YM3438CCAM-M1VA3.flac
TFIV-LEVEL1A-YM3834CCAM-Original-M1VA3.flac

Observations:
-Here you have Tiido's original CCAM recording along with my own both in Original and filtered form. You can appreciate how my -original- Recording is very similar to Tiido's. The RetroGamer's CCAM strong Lowpass contrasts sharply however.
-This song is a good example to appreciate how the PSG is weaker in the M2VA4 than on its other CCAM counterparts. The VA7 seems a bit weaker than the VA1 too but the difference is small. It seems clear to me that the installation of a CCAM on a M2VA4 might require a fix to restore a more proper PSG level.


-Mega Turrican Intro



I choose this one because it is from a very high quality OST for the genesis and the intro is also one of the original sample recorded by Tiido for his CCAM mod.

Tiido's original Demo.
MT-Intro-Stock-M1VA7
MT-Intro-Stock-M2VA3
MT-Intro-CCAM-M1VA7.flac
MT-Intro-CCAM-M2VA1.flac
MT-Intro-CCAM-Original-M2VA1.flac
MT-Intro-CCAM-M2VA3
MT-Intro-CCAM-M2VA4.flac
MT-Intro-YM3438CCAM-M1VA3
MT-INTRO-YM3834CCAM-Original-M1VA3.flac

Observations:
-If you listen to Tiido's orginal CCAM recordings, you will notice that the cymbal is not distorted. Both my standard and filtered CCAM recordings have the cymbal distortion. I cannot explain why at this moment but I notice that the music on Tiido's version is slightly slower and lower pitch. Might be something to do with console localization.
-Also, Once again, the silences between parts in the intro reveal audible background/processing noise in the VA7 and VA1. The VA4 CCAM is however very clean.
-Slightly weaker PSG in VA4 is again noticable.

*I do not have a model 1 YM2612 recording of this atm but I prefer the more filtered retrogamer's CCAM version over Tiido's original this time. There is too much highs already in there and more filtering actually helps it i think. Tiido's sample, while it sounds good, is pretty ear piercing. I think a in-between would be ideal here.

-Mega Turrican Level 1



I really like this song so this is probably why I recorded it when I did my Postrecap M1VA3 recording last year.
I did the recording with the CCAM VA7 as an afterthough To have a comparison between a stock YM2612 console and a CCAM

-See upper links for Tiido's original demo.
MT-Level1-VA3(postrecap).flac *This recording has CRT whine noise due to connected CRT.
MT-level1-CCAM-M1VA7.flac

Observations:

*I think Tiido's original demo sounds too heavy on the treble here, just like for the previous track.
However I think this is a tough call between old Model 1 and my retrogamer's CCAM. I feel this can be equally enjoyable on my CCAM or original Model1. It comes out well on both. The CCAM superior definition and separation makes it good in a way, while the model 1 higher saturation and sound pressure makes it enjoyable in another. I cant really decide on this one, I guess it depends on your mood



-Biohazard Battle - Level1



I picked this one up because it makes some interesting use of a yamaha YMxxxx chip. Lots of envelopes and special effects makes it a good candidate to check for nuances between versions of the chip. I also like this OST for its unique insectoid creepy style

BHB-BA3(postrecap).flac *This recording has CRT whine noise due to connected CRT.
BHB-level1-CCAM-M1VA7.flac
BHB-Level1-CCAM-M2VA1.flac
BHB-Level1-CCAM-M2VA4.flac *This recording has CRT whine noise due to connected CRT.

Observations:


-Despite my original intention of finding subtleties between YM2615 and YM3438 with this one, It did not really happen. As far as i have noticed the execution is pretty faithfull on both chips.
-However this track turns out to be pretty good at illustrating the craps and artifacts out the Model 1 ym2612. Just compare the first few seconds between any CCAM and the ym2612.

* I prefer CCAM on this one, Sound tends to come slightly overdriven and grainier on the stock Model1 ym2612. This music is already a bit rough and grainy to begin with so I think It comes out more pleasant on my CCAM recordings.

-Contra Hard Corps - GameStart



I chose to use this as I thought this game has it easy to make your ears bleed with all those cray cray explosion sounds.
The music with its distorted-electronic vibe is also an interesting study subject

CHC-Gamestart-M1VA6.flac
CHC-Gamestart-CCAM-M1VA7.flac
CHC-gamestart-CCAM-M2VA1.flac
CHC-gamestart-CCAM-Original-M2VA1.flac
CHC-gamestart-CCAM-M2VA4.flac
CHC-Gamestart-YM3438CCAM-M1VA3
CHC-INTRO-YM3438CCAM-Original-M1VA3.flac


Observations:
-This shows once again the background noise Issue I experience with the M2VA1 and M1VA7 CCAM. By opposition VA4 CCAM and stock M1VA6 are clean.
-The PCM voice comes out a bit cleaner on the CCAM.
-The "sweeping" sound immediately at the beginning is pretty harsh on an unfiltered -original - CCAM. Adjusting low pass on a CCAM is tricky as all games are not made equal.


-Sonic 2 : Emerald Hill 1



Ok I choose this one because I felt that I basically "had" to include some sonic in my test run but honestly I think this is probably the less interesting sample series. It is loud en eventful enough to hide noise issues, seems to be coming out well pretty much all the time.

Sonic2-Emerald1-VA3(postrecap).flac *This recording has CRT whine noise due to connected CRT.
Sonic2-Emerald1-CCAM-M1VA7.flac
Sonic2-emerald1-CCAM-M2VA1.flac
Sonic2-emerald1-CCAM-Original-M2VA1.flac
Sonic2-emerald1-CCAM-M2VA4.flac
Sonic2-Emerald1-YM3438CCAM-M1VA3
Sonic2-Emerald1-YM3438CCAM-Original-M1VA3.flac

Observations:
-This would need to be confirmed but I experienced some sound glitches on the M2VA4. Once in a while it would output a small patch of white noise or some similar glitch sound. It is not on the recording as it does not appear all the time. Might be caused by a problem with my cart or motherboard too, do not know. Would require more play time on the VA4.

*While it is good on both CCAM and old model1, I prefer CCAM just a little bit. It just comes out Nicer and smoother.



Notes on the hardware setup.

-Retrogamer343's CCAM board; It is the very CCAM board I used in my recordings.


-A look at the overall setup:
This is my M2VA4 board but I used exactly the same configuration for all my CCAM tests. A naked board with a separate CCAM connected with Shielded cables kept far from the board. In the case of the M1VA7 and M2VA1 I had to play around with the orientation of the CCAM section relatively to the console motherboard to minimize interferences. All my recordings were done with a configuration where I deemed the interferences "minimized". There was no such problem with the M2Va4. The thing was silent, period.



Things to do/investigate at this point. (11/08/2013)

-Get more recordings, especially of rarer stock consoles.
-See how to best restore the PSG level in the VA4 CCAM.
-Test some other audio mods, such as the volume balance fix for va2,2.3 and possibly some other amp designs.
-Make an overall sound rating of each consoles, including mod solutions. ( needs more data )

[MaxWar]

"reserved"

[Drakon]

Adjust the 0.022 uf caps up / down to adjust the filter cutoff of the ccam. You can greatly increase the treble range but if you go too far it introduces clipping. I like your lazy wiring where you don't wire up the 32x / scd lines.

[MaxWar]

Adjust the 0.022 uf caps up / down to adjust the filter cutoff of the ccam. You can greatly increase the treble range but if you go too far it introduces clipping. I like your lazy wiring where you don't wire up the 32x / scd lines.

Thanks for the information, will definitely try this.


I have another experiment planned where I will try to reduce the interferences on VA7 CCAM as much as possible.
-Will Fully shield the CCAM board and I will unsolder the SCD & 32X wires because I am worried they might act as antennas when left unconnected like this.

[Ace]

[CENTER]Comparative audio recordings
of the Genesis/Megadrive consoles.
By MaxWar.
*snip*

Aw, damn it, I was gonna do exactly this on my big Genesis model and motherboard revision thread, but stock hardware only and with different samples.

-Get more recordings, especially of rarer stock consoles. Like M2 Va2,2.3, VA3 VA4 ( I do not possess VA3 )

You could take some of my samples when I upload them to my big Genesis model and motherboard revision thread. I have access to many different Genesis motherboard revisions (though I don't have access to some of the games you posted samples from).

-Find out how and why the CCAM got filtered in between Tmee's demo and Retrogamer's board.

As Drakon mentioned, the 0.022uF capacitors in the audio circuit were replaced with different capacitors. Their capacitance is higher than what TmEE used, so there's more low-pass filtering. If I were to hazard a guess as to why this was done, I'd say it's due to the high frequencies of the YM2612 and YM3438 being fairly loud compared to low frequencies. Personally, having a low-pass filter like the Genesis Model 1 has with about 3.2KHz to 3.5KHz cutoff sounds better than raw audio out of the YM2612/YM3438 as there's a better balance between low frequencies and high frequencies.

-Make an experiment with the CCAM board fully isolated in a Faraday cage to see if it helps with the noise with the VA1 and VA7

I have no idea what this is, but the noise you describe sounds like noise coming off the VDP. Might not be fixable.

-See how to best restore the PSG level in the VA4 CCAM.

You could probably adjust the 1.5Kohm resistors on the PSG outputs.

-Test some other audio mods, such as the volume balance fix for va2,2.3 and possibly some other amp designs.

By next month, I should have the Mega Amp complete for all OPN2 FM chips. I say screw the volume balance fix for the VA2 and VA2.3 Genesis Model 2s as the Mega Amp not only resolves that, but also resolves the crappy filtering common to all Genesis Model 2s (higher-order low-pass filter which results in degraded audio quality due to a heavier roll-off).

[MaxWar]

Aw, damn it, I was gonna do exactly this on my big Genesis model and motherboard revision thread, but stock hardware only and with different samples.

You could take some of my samples when I upload them to my big Genesis model and motherboard revision thread. I have access to many different Genesis motherboard revisions (though I don't have access to some of the games you posted samples from).

The aim of my thread is to focus on modding, kind of try to find the best possible hardware combinations, which seems to vary depending on the game.
I still need some stock console recordings for comparing how they sound to modded ones.

Talking of which, I know you have studied genesis hardware variation extensively. I am not looking to get all of them but I would like to have a version to experiment with every main sound variant and their respective mods. Right now I have Model 1: Va3,Va6,Va7 Model2 Va1,Va2.3(with sony encoder) and a Va4.
Do you recommend getting any more?
I think my collection makes a good coverage, I would still like to have a M2VA3 and maybe some of the exotic combo variants like Xeye of CDX though. I am not interested in the model 3 and later firecore and suff atm.

As Drakon mentioned, the 0.022uF capacitors in the audio circuit were replaced with different capacitors. Their capacitance is higher than what TmEE used, so there's more low-pass filtering. If I were to hazard a guess as to why this was done, I'd say it's due to the high frequencies of the YM2612 and YM3438 being fairly loud compared to low frequencies. Personally, having a low-pass filter like the Genesis Model 1 has with about 3.2KHz to 3.5KHz cutoff sounds better than raw audio out of the YM2612/YM3438 as there's a better balance between low frequencies and high frequencies.

This makes sense. I will experiment with different values. I think somewhere in between Tmee's original and the stock Retrogamer's pcb will suit my taste. I may even try to make an adjustable cutoff in the end.

I have no idea what this is, but the noise you describe sounds like noise coming off the VDP. Might not be fixable.

Listen to the CCAM recordings of Mega Turrican Intro. You will hear the noise on the VA7 and VA1 when there are silences. There seems to be a part of this noise that react to how I place the wires and CCAM board around so it is at least in part Inducted. Hence Why I want to make an experiment with an Isolated circuit.
Funny how the VA4 is so damn clean though, I am very pleased with it. With restored PSG balance and ajusted frequency cutoff It should be a very fine genesis for audio.

You could probably adjust the 1.5Kohm resistors on the PSG outputs.

That is what I had in mind, Will try to find the proper value for the VA4.

By next month, I should have the Mega Amp complete for all OPN2 FM chips. I say screw the volume balance fix for the VA2 and VA2.3 Genesis Model 2s as the Mega Amp not only resolves that, but also resolves the crappy filtering common to all Genesis Model 2s (higher-order low-pass filter which results in degraded audio quality due to a heavier roll-off).

Ok will put this to wait

[omp]

By next month, I should have the Mega Amp complete for all OPN2 FM chips. I say screw the volume balance fix for the VA2 and VA2.3 Genesis Model 2s as the Mega Amp not only resolves that, but also resolves the crappy filtering common to all Genesis Model 2s (higher-order low-pass filter which results in degraded audio quality due to a heavier roll-off).

Keen!

[MaxWar]

Experiment time!

Ok so I did an experiment where I completely isolated the CCAM board in a grounded conductive shell, This is normally an effective method of blocking interferences from electromagnetic fields.

I figured an easy method to do this would be to use a tuna can. So I rebuilt my CCAM test rig inside the can.


I had to use the help of aluminum tape as I discovered the hard way that you don't just solder on aluminum like that, it wont stick.
I managed to get the whole thing grounded with the use of the RCA jacks and partially inverted aluminum tape.
I decided to rename this; The CCAN!


I then made a VA7 recording of Mega Turri-can (pun intended) intro. Sadly the CCAN did not fix the noise issues. In fact it sounds identical to my previous recording. No audible difference at all
You can hear the exact same buzzing as before, I wont even bother to upload the recording unless requested. I think ACE was right on the money and the noise is generated by the VDP and contaminates the sound right on the motherboard. In fact the noise modulates with what happen on the screen.


However before the CCAN the interferences would modulate and potentially get worse when I moved the CCAM board around. I had to place it just so to make it minimal. With the CCAN it seems the noise floor is more constant.
So the CCAN seems to work but It does not fix what I had hoped it would fix.
No bid deal, I did it for science, and I got some photos and a silly pun as souvenir

The bad news is that it appears from my experimentation that VA7 and m2VA1 board induce noise in the sound line on the motherboard level. The noise is related to video processing it would appear. It is not a terrible noise, on some games it is even practically unnoticeable but it is still enough to annoy the more anal audiophiles.

The good news is there is a solution to enjoy CCAM noise free, Its called the M2VA4.

[Drakon]

You're really sensitive...my board in my va7 installed over the ground plate sounds good enough. The only thing that bothered me was too much low pass filtering.

[MaxWar]

You're really sensitive...my board in my va7 installed over the ground plate sounds good enough. The only thing that bothered me was too much low pass filtering.

Did you download my Mega turrican intro sound files ?

[Drakon]

Did you download my Mega turrican intro sound files ?

No....I'm fine with youtube it doesn't sound any lower quality than the actual thing on my sound hardware.

[MaxWar]

No....I'm fine with youtube it doesn't sound any lower quality than the actual thing on my sound hardware.

Just Give it a try, it wont hurt. You will at least know what i am talking about.
I hosted it with google so the download should no be too long. Just get MT-INTRO-CCAM-VA7 and MT-INTRO-CCAM-VA4

[omp]

Call me crazy, but sometimes I kinda like the old hiss. It takes me back when the family would sit around the wireless.

[Drakon]

Just Give it a try, it wont hurt. You will at least know what i am talking about.
I hosted it with google so the download should no be too long. Just get MT-INTRO-CCAM-VA7 and MT-INTRO-CCAM-VA4

I can guess what you're talking about, my point it is it's not loud enough on my system to annoy me.

[MaxWar]

Call me crazy, but sometimes I kinda like the old hiss. It takes me back when the family would sit around the wireless.

The old model1 has a hiss, and its a soft and constant thing. No big deal.
On the M1VA7 and M2VA1 CCAM its more like buzzing, which is annoying. The buzzing changes with what the machine is doing, its like you can hear it thinking.