The two Panasonic MSX Turbo-Rs have a very good audio circuit design that has everything it should have for its price range. But the result was poor because the circuit was terribly calibrated, resulting amongst other problems, in:

  • The slot sound was too loud, meaning you could barely hear the PSG drumkit when an SCC cartridge was used.
  • On the other hand, the OPLL sound was too quiet, so the soundtracks of Micro Cabin games, Valis-2, Starship Rendezvous and others that used the PSG and FM simultaneously were severely affected. Most chords were derailed, and Micro Cabin's trick of using the PSG to complement the OPLL didn't match anymore. The PSG kept screaming all the time.
  • The OPLL low-pass filter was even stronger than the already incorrect Yamaha reference design, resulting in a terribly muffled FM sound that made the previous problem even worse.
  • The global audio-out low-pass filter was also too strong, to the point that the borders of the square wave output of the PSG were totally round, degrading many beautiful chords of famous Konami soundtracks for this chip.
  • The global audio-out level was too weak, resulting in poor SNR and weak bass.

This fix recalibrates the audio circuit for maximum performance, and what astonishing difference that it does. It then blows any other MSX sound quality out of the water.

This recipe corrects all these problems, and normalizes the mixing volume between the slots (usually SCC or MSX-Audio), PSG and OPLL, to match the levels of the Panasonic MSX2+ and Sony MSX2+ machines.

Comments (55)

By raymond

Champion (318)

raymond's picture

18-08-2017, 07:37

Ah, nice. Improvements are always good Big smile

By KdL

Paragon (1109)

KdL's picture

18-08-2017, 14:31

like+1000000 thanks!! Running Naked in a Field of Flowers

By jltursan

Prophet (2112)

jltursan's picture

19-08-2017, 14:16

Good work!, many, many thanks!

By sd_snatcher

Prophet (2775)

sd_snatcher's picture

21-08-2017, 00:31

I published four lists of soundtracks comparing the after/before of the FS-A1ST audio fix, so anyone can check themselves the difference in terms of sound quality and how much detail was being missed. I hope you enjoy it.

EDIT: I used VGMplay for the non-Micro Cabin soundtracks, but I noticed that some tracks have some weird glitches, regardless of the fix. It's very noticeable in the beginning of Metal Gear-trk2, in the drumkit of Mr Ghost and in the opening song of Greatest Driver.

PS: Be sure to use a decent sound equipment. Notebook speakers won't do. :)

By Grauw

Enlighted (7321)

Grauw's picture

21-08-2017, 00:48

Oh wow, what a difference.

Thanks for posting this extensive comparison, must’ve taken some time to compile!

Re. VGMPlay issues, will look into that…

By Victor

Champion (389)

Victor's picture

21-08-2017, 06:10

Grauw wrote:

Oh wow, what a difference.

YES!! The difference is huge!!

Great work FRS!!

By Guillian

Prophet (3139)

Guillian's picture

21-08-2017, 09:56

Great work! Thanks for sharing.

By raulsantacruz

Champion (486)

raulsantacruz's picture

21-08-2017, 14:58

Absolutely great!!!! I can't wait until the moment to fix my computer!

By sd_snatcher

Prophet (2775)

sd_snatcher's picture

21-08-2017, 15:51

Grauw wrote:

must’ve taken some time to compile!

I got a cold, so in my current condition you can imagine it was like a punch. The vertigo and dizziness returned quite strong.

But I can't just stay still, so I decided to do something that didn't require too much concentration. Smile

By JohnHassink

Ambassador (5298)

JohnHassink's picture

21-08-2017, 18:35

Wow sd_snatcher, not only is the comparison very interesting, your selection of songs is also really enjoyable in itself. Smile

My guess about the Greatest Driver glitches are warped parameters in pitchbending and "note linking" (new tone without retriggering the preset) commands.
Though it's puzzling why it only affects certain instances and doesn't seem to happen in the "original" version.

Maybe it just isn't...
(•_•)
( •_•)>⌐■-■
...using the greatest driver.
(⌐■_■)
YYYYYEEEEEAAAAAHHHHHH

By JohnHassink

Ambassador (5298)

JohnHassink's picture

21-08-2017, 18:31

If it helps, I noticed some skewed frequencies in the tracks from Psycho World (the 'brass' section shortly after the beginning), Undeadline (basslines and some piano notes) and Xevious (one note in the lead missing) as well.
As there doesn't seem to be any pitchbending or note linking going on during those instances, my earlier assessment is probably incorrect.
Again, the problems seem to be present in the Fixed versions only.

By Grauw

Enlighted (7321)

Grauw's picture

21-08-2017, 20:03

The Greatest Driver glitches are from too fast OPLL access, although as you say I only hear them in the fixed ST recordings. Which is a bit puzzling, especially if that’s also the case for other songs. It suggests a machine-specific difference.

@sd_snatcher Did you perchance upgrade something related to CPU speed on the fixed ST? Or maybe the other ST was running in Z80 mode? Otherwise, if there are no differences to speak of, I might’ve timed things a bit too tightly according to my own GT’s tolerances. I’ve had an issue with this in the past for an MSX-Audio modded with a clock crystal (Meits’s).

That doesn’t explain the PSG issues though. Maybe there’s something I forgot to initialise.

By Louthrax

Paragon (1832)

Louthrax's picture

21-08-2017, 21:31

Grauw, not sure if that's related, but about the PSG issues, that might be caused by the VGM file itself, if it does not contain initialization for all registers at start. For example, I did a VGM recording using openMSX from a simple BASIC PSG PLAY "A" instruction: this causes noise to be added to the "A" when playing that file back with VGM play. VGMPlay initializes all registers to 0 (not saying that's a bad thing), but by default this activates the PSG noise. Of course it works if you record things before the reset or power-up.

Maybe a full initialization sequence could be added in the openMSX VGM recording script (with the default after-boot values)...

By Manuel

Ascended (14468)

Manuel's picture

21-08-2017, 21:51

I think the idea is that you record in openMSX including initialization (for PSG that may be the BIOS starting up) and cut out some silence parts out later.

How could the script add an initialization sequence if it doesn't even know what it should be for the music that will be recorded?

By Louthrax

Paragon (1832)

Louthrax's picture

21-08-2017, 21:55

Manuel wrote:

How could the script add an initialization sequence if it doesn't even know what it should be for the music that will be recorded?

That's the question... Maybe if the registers are mirrored inside openMSX and accessible from TCL they could be written at script start? (my guess is that for now the script writes in the VGM file only what's written on the various audio ports / memory addresses).

By ren

Paragon (1127)

ren's picture

21-08-2017, 22:14

Wow, differences seem insane, like the originals almost sound muted? Is there actually such a difference in volume/clarity/loudness, or does the recording itself also play part in this? I can hardly believe the original MSX sounds that bad.

Thanks for the (huge! amount of) recordings (and indeed nice selection Wink) Gonna compare some stuff with openMSX's rendering when I get to it Wink

Something I'm wondering about though: one may assume the various composers heard their work as well on an original (thus prolly flawed) MSX.. So now with the fix it may actually *not* sound the way it's intended right? (But then, there were already differences between models..)

By Grauw

Enlighted (7321)

Grauw's picture

21-08-2017, 22:55

@Louthrax In principle I should mirror the initial state from VGMPlay for PC, but I might’ve made a mistake. Writing the initial register state in the script is not necessary I think, the game should either initialise everything or rely on boot-up initial values, not on something arbitrary.

@ren Since everything sounds 1000% better, I think the original composers would have no complaints Big smile. The question what machine composers made their music on is a similar question as “did they make their game with an S-Video or composite or RGB connection”, “what was the dot pitch of their monitors”, “did all artists use the same monitors”, “what type of speaker did the musicians use” and “did they even develop the game on an MSX”. There is going to be differences, it’s part of the deal.

But I think bringing the mixing in line with popular models which have good balanced mixing is never a bad thing. And as for the low-pass filter, I would say at least the turboR was particularly terrible so upping the cutoff frequency is never a bad thing. And in emulators we’re also hearing the unmuffled sounds and nobody complains about that. Also, 1000% better Big smile.

By JohnHassink

Ambassador (5298)

JohnHassink's picture

22-08-2017, 00:37

Grauw wrote:

The Greatest Driver glitches are from too fast OPLL access

Is it safe to assume then that the glitches in the other games are caused by that same thing?

By Grauw

Enlighted (7321)

Grauw's picture

22-08-2017, 00:49

Yes, the OPLL ones at least. Nothing to do with FRS’s audio fix.

By JohnHassink

Ambassador (5298)

JohnHassink's picture

22-08-2017, 02:44

So, in terms that laymen (like me) can understand, the data is sent to the chip faster than it can process, so that it uses previous frequency information, that lags behind the 'action'?

By Grauw

Enlighted (7321)

Grauw's picture

22-08-2017, 11:45

Yeah, or part of the previous frequency information, since it is spread out over two registers.

Drawing attention back to the topic… Smile

sd_snatcher wrote:

I published four lists of soundtracks comparing the after/before of the FS-A1ST audio fix, so anyone can check themselves the difference in terms of sound quality and how much detail was being missed. I hope you enjoy it.

EDIT: I used VGMplay for the non-Micro Cabin soundtracks, but I noticed that some tracks have some weird glitches, regardless of the fix. It's very noticeable in the beginning of Metal Gear-trk2, in the drumkit of Mr Ghost and in the opening song of Greatest Driver.

PS: Be sure to use a decent sound equipment. Notebook speakers won't do. :)

By syn

Paragon (1852)

syn's picture

24-08-2017, 16:36

sd_snatcher wrote:

I published four lists of soundtracks comparing the after/before of the FS-A1ST audio fix, so anyone can check themselves the difference in terms of sound quality and how much detail was being missed. I hope you enjoy it.

Okay I did a quick listen. I don't own a Turbo R (yet) so I don't have much to gain by this. Nevertheless I would give you my personal opinion, to help you maybe further improve this mod.

btw I disregard the difference in overal volume level, since that is most definitely an improvement.

PSG+SCC: Balance is improved, overal sound is good. Improves a lot of the tunes.
PSG only: Sounds like an improvement, things are more clear. It would seem some of the noise register sounds (hihats etc) were a lot softer before the mod. Sounds has more "texture" i guess (if that makes any sense).

However the OPLL seems to have way too much treble. I've talked on #msxdev about this briefly (like a few minutes), it would seem your unmodded turbo R (st) indeed sounds a more "muffled" compared to a GT (that lowpass filter thing i guess). So fixing could be needed.

But in my opinion the fixed versions of some of the songs just don't sound right. For example your comparison of PSG+OPLL+SCC (sorcerian tune), I prefer the original unmodded version. The fixed version has so much treble around 0:48 that it starts sound unpleasant for me ears if I dont turn down volume. Same for some of the OPLL Fray tunes. I guess it depends on how much "high" was present in the original, other songs sound alright.

And no, this is not me based on years of being used to certain settings/machines, since I barely know half of the tunes you posted.

Btw does your mod for the sanyo make sound about the same as this? (not asking/expecting you to do a recording)

ren wrote:

Something I'm wondering about though: one may assume the various composers heard their work as well on an original (thus prolly flawed) MSX.. So now with the fix it may actually *not* sound the way it's intended right? (But then, there were already differences between models..)

This is what I am wondering about too. I dont know about the exact release dates of the games or development machines of Microcabin, but it seems that the "treble problem" that I talk about earlier seem to more affect "newer" microcabin games. I suspect they were made on a muffled turbo r, and the composers just upped the higher instruments' volume to compensate for the lowpass filter.

By Grauw

Enlighted (7321)

Grauw's picture

25-08-2017, 01:24

syn wrote:

it would seem your unmodded turbo R (st) indeed sounds a more "muffled" compared to a GT (that lowpass filter thing i guess).

In the course of some VGMPlay debugging, I felt my GT indeed didn’t sound as bad as the unfixed ST. Though of course the listening conditions were different, and this was only a casual observation. When I get around to ordering the components and sitting down to fix my GT audio, I’ll be sure to make before / after recordings.

About treble, I wonder how you feel about emulator renditions of those Fray songs?

Btw, regarding the part of the Sorcerian song that you mentioned, I love how it sounds really “snappy” after the fix. The fast attack on the modulator of the lead voice gets kinda lost in the muffled version.

By Louthrax

Paragon (1832)

Louthrax's picture

25-08-2017, 09:28

I like the fixed sounds too. Matter of taste here of course, could be compared to preferring CRT blurry display vs LCD sharp square pixels (in this case I prefer the CRT!).

By Grauw

Enlighted (7321)

Grauw's picture

29-08-2017, 23:19

Hey FRS,

Would it also be better to use polypropylene capacitors for C51 / C45 on the GT, or do they have to be ceramic?

By sd_snatcher

Prophet (2775)

sd_snatcher's picture

29-08-2017, 23:38

Thanks for asking, I'll add this info to the article. If you can find polypropylenes that fit in there without the risk of ripping the pads out of the board, you can used them. This means: *only* if they are the small 50V type. Do not use the 100V rating because they're way too bulky to install there.

Plz also keep in mind that the recommended type of ceramics, if used, are not the crappy Y5V or the not-so-great X7R. Use the more expensive C0G (aka NP0) type as they are of excellent quality and much more appropriate for this application.

By sd_snatcher

Prophet (2775)

sd_snatcher's picture

29-08-2017, 23:48

Oh, and you can use polystyrene 50V capacitors for the C51/C45 too.

By Grauw

Enlighted (7321)

Grauw's picture

30-08-2017, 00:48

Cool, then I can order all-Panasonic components Big smile.

Here’s my DigiKey shopping list (with assortment of caps so I can compare different values).

Index,Quantity,Part Number,Description,Customer Reference,Available Quantity,Backorder Quantity,Unit Price USD,Extended Price USD,
1,10,PCF1299CT-ND,CAP FILM 1800PF 2% 50VDC 0805,,10,0,0.36100,3.61,
2,10,PCF1177CT-ND,CAP FILM 10000PF 2% 16VDC 0805,,10,0,0.34600,3.46,
3,10,PCF1174CT-ND,CAP FILM 5600PF 2% 16VDC 0805,,10,0,0.37400,3.74,
4,10,PCF1301CT-ND,CAP FILM 2700PF 2% 50VDC 0805,,10,0,0.32100,3.21,
5,10,PCF1287CT-ND,CAP FILM 180PF 2% 50VDC 0805,,10,0,0.35700,3.57,
6,10,PCF1286CT-ND,CAP FILM 150PF 2% 50VDC 0805,,10,0,0.35700,3.57,
7,10,P22KDACT-ND,RES SMD 22K OHM 0.1% 1/8W 0805,,10,0,0.30200,3.02,
8,10,P15KDACT-ND,RES SMD 15K OHM 0.1% 1/8W 0805,,10,0,0.30200,3.02,
9,10,P47KDACT-ND,RES SMD 47K OHM 0.1% 1/8W 0805,,10,0,0.30200,3.02,

Tomorrow I’ll see if I can find some other nice stuff that I’d like to have to get above the $60 free shipping :).

By sd_snatcher

Prophet (2775)

sd_snatcher's picture

30-08-2017, 01:36

Good thinking! Polyphenylene Sulfide capacitors are an excellent choice too, specially in SMD form factor. I'll add this option to the article because they're very easy to install and it looks original. I'll probably remove the polypropylene option for the TRs because it's impossible to find them at the right size these days, and it just makes the text more confusing. Having two excellent options of capacitors for audio like the PPS and the C0G is enough.

BTW, for those interested in this topic here's an excellent article comparing the performance of the C0G capacitors with PPS and other plastic capacitors.

By Grauw

Enlighted (7321)

Grauw's picture

30-08-2017, 01:57

For me the “Stable Frequency Characteristics” graph in this overview was pretty illustrative.

For the resistors I picked thin film ones which are supposedly better for audio purposes (though a bit lower wattage, and I’m not sure the high-end audio characteristics will survive the rest of the MSX’s circuitry :D, so maybe just a bit of a waste of money). And the higher value caps are only rated for 16V, I assume that’s no problem either since line level is just 1.7V and before the opamps I guess it’s even less.

As for the Polyphenylene, I just saw “film” and “polyflufluflulene” so that was a bit accidental :D.

By sd_snatcher

Prophet (2775)

sd_snatcher's picture

30-08-2017, 02:00

Grauw wrote:

For me the “Stable Frequency Characteristics” graph in this overview was pretty illustrative.

Yes, X7R ceramic capacitors are known for being crap. C0G ceramics are a totally different beast though. BTW, the original audio capacitors in the Turbo-R were C0G, so they were worried about the sound quality. Too bad that excellent components were wasted with such an horrible calibration.

By roadfighter

Champion (363)

roadfighter's picture

31-08-2017, 10:08

@Grauw, you could order some more components, so you could make diy sets for the turbo-r's.
Maybe include all capacitors so we could do a complete recap of the computer's.
Are the differences between the St send Gt "big"? Component wise? Then one set could be used for St or Gt.

And I noticed something strange, the microphone of the turbo-r's are not completely muted.
When you put on your computer and blow or whistle in to the mic. You can hear it in the speakers (audio out).
I can imagine that this causes some background noise no one whants. Is there a fix for this?

By Grauw

Enlighted (7321)

Grauw's picture

31-08-2017, 10:33

@roadfighter Yeah, I am ordering at least 10 of each because it’s cheaper (bulk discount), and I want to get to the free shipping limit. I think I will put the components that are left over into little seal bags and bring them to the Nijmegen fair.

The ST uses the same components as the GT minus one, so the same set of components can be used.

I’m not ordering full recap sets as sd_snatcher told me earlier that the Japanese caps in the turboR are really good quality and not affected (as much?) by the capacitor manufacturing problems of the 80s. So since my GT’s caps are looking fine and I’m having no issues since I applied the jailbar fix, now I feel it’s best to leave it as-is. Less chance of me damaging the main board in the process as well :).

By roadfighter

Champion (363)

roadfighter's picture

31-08-2017, 21:23

@Grauw,
Nijmegen is a good idea, but I want to fix my turbo-r's before that Tongue
And good to know that the caps are of good quality, I will leave them be then.

By OeiOeiVogeltje

Paragon (1189)

OeiOeiVogeltje's picture

16-09-2017, 18:21

@Grauw i just sent you an email..

By Grauw

Enlighted (7321)

Grauw's picture

01-12-2017, 00:02

Today I modified my turboR (finally), and as promised, a review with comparisons!

I made recordings of the following six songs: 1) Greatest Driver - Opening (FM), 2) Xak - Opening 2 (FM+PSG), 3) Xak - Fort (FM+PSG), 4) Xak - Land of Flames, The Sky (FM+PSG), 5) Xak - Millie’s Theme (PSG) and 6) Space Manbow - Stage 1 (SCC+PSG).

The SCC is played on the MegaFlashROM’s SCC, a real SCC is comparable. Tip: load the audio files side-by-side in your favourite audio editor (e.g. Audacity) and mute / solo the tracks one by one.

TurboR FS-A1GT - Original

Filter chain:
OPLL-1: 4.7 kΩ / 33000 pF = 1026 Hz
OPLL-2: 56k / 470p = 6047 Hz
Global: 39 kΩ / 560 pF = 7287 Hz

TurboR FS-A1GT - WX filter

Filter chain:
OPLL-1: 4.7 kΩ / 10000 pF = 3386 Hz
OPLL-2: 56k / 150p = 18947 Hz
Global: 47 kΩ / 270 pF = 12542 Hz

Note: I modified FRS’s audio fix to use filter values similar to the Panasonic FS-A1WX. Although there OPLL-1 is 2258 Hz and OPLL-2 is absent, but close enough.

TurboR FS-A1GT - SFG filter

Filter chain:
OPLL-1: 4.7 kΩ / 1800 pF = 18813 Hz
OPLL-2: 56k / 150p = 18947 Hz
Global: 47 kΩ / 180 pF = 18813 Hz

Yamaha CX5MII

Filter chain:
OPLL-1: 2.2 kΩ / 2200 pF = 32883 Hz
OPLL-2: absent
Global: 4.7 kΩ / 1500 pF = 22575 Hz

Note: I used a Monster Sound FM PAQ for OPLL on the CX5MII.

=== Review ===

FRS’s audio fix consists of three main parts: 1. correction of the balance, 2. increased output volume, and 3. reducing the low-pass filter. I’m going to look at these one by one, comparing with Yamaha’s great CX5MII as a reference machine when needed.

Balance

The fix changes two mixing resistors; the PSG resistor from 56 kΩ to 22 kΩ, and the OPLL resistor from 47 kΩ to 15 kΩ. This means that relative to external sound chips the PSG and OPLL are both mixed in louder now, the OPLL also a bit more than the PSG.

The difference is quite noticeable in the SCC test (song 6). Before, the PSG drums would be barely audible, drowned out by the SCC music. After, the drums are mixed in correctly, matching the CX5MII. (Note, due to recording volume difference the original’s SCC song is louder, don’t get fooled thinking louder = better, normalise the volume manually if needed.)

The FM-PSG mixing change can be heard well in the second Xak song (song 3). Before, the PSG was a bit too prominent, whereas after it is much more balanced, square waves blending well with the FM tones which is so important in Micro Cabin music.

Output volume

Since the PSG and OPLL mixing levels were increased their total output has as well. Additionally, on the GT the resistor on the final op-amp is also changed from 39 kΩ to 47 kΩ, increasing the amplification, matching the ST and the WX. Indeed, on the ST this is already at the correct value so it gets less of a boost.

Because the volume used to be so low, I had to amplify the output on my mixer quite a lot, and the hum from the video interference became very noticeable. I always had to carefully pick mixing volumes, ducking the volume in silent parts of recordings, and I would use “color 12,0,0” to reduce the video interference noise as well.

After the fix, the output volume increased quite significantly (about doubled), and matches the output volume of my CX5MII. The noise floor is barely noticeable anymore. Great!

Filtering

Last, the low-pass filter. This has been the biggest source of debate. The turboR is well known for its excessive low pass filtering, as you can see in the numbers I mentioned for the original filter chain above. As a result, the sound output sounds very muffled, the OPLL in particular. It was such a known issue that it is noted on the Japanese Wikipedia page, stating that people would often remove the filtering capacitors as a quick fix (even though of course the filter is there for a reason).

A low-pass filter lowers the volume for higher sound frequencies above a so-called cut-off frequency. From there on the higher the frequency, the more they are attenuated. Given that a middle A is 440 Hz, as you can see the turboR’s 1026 Hz cut-off frequency is just barely an octave above that. No wonder it sounds muffled!

The low pass filter cut-off frequencies are determined by resistor-capacitor combinations (“RC” filter), and by increasing the resistor value or reducing the capacitor value you increase the cut-off frequency. The formula is pretty simple, and there are handy online tools to calculate it. Because there are three filters in series, they are applied cumulatively, increasing the slope of the attenuation.

The filter improvements by FRS crank these filter values up quite a bit, making all the muffling disappear. The settings are based on the filter in the Yamaha SFG-05 sound module, with all three filters kicking in around 18 kHz, just below the human audible hearing frequency.

Because these filter values get pretty close to the OPLL’s sampling frequency though (at 49716 Hz), and the OPLL also uses the filter for mixing its channels, there was some debate whether this would not reduce the mixing quality. For that reason I’ve also tried out an alternative filter setting, based on the values of the Panasonic FS-A1WX MSX2+ computer. This should definitely be a “reference” value that everybody will like :).

Either way, so after trying them out, I have to say it’s a huge improvement, the both of them. Already the WX-based setting sounds so much better, and if I compare them side by side the SFG-based setting sounds even more crisp and removes the last audible remnants of muffling. Which is better is subject to opinion (which I’m looking forward to hearing about!), but I think there’s no debate that either way it is an improvement over the original. Personally I think I prefer the SFG-type version.

I also hope the PCM audio quality will be improved significantly, it sounded quite filtered when I played Sega MegaDrive music with PCM before. I haven’t been able to try it yet though, since the keyboard isn’t attached yet.

Applying the fix

Couple of notes on applying the fix:

  1. To open the turboR body, after removing all the screws, pry apart the side near the power button, then pull your hands forward to loosen the keyboard area, and once everything feels nice and loose, lift and push the top half of the body backwards to get it to release the clamps in the back. Just use your hands, no need to damage the plastic with a screwdriver.
  2. To unsolder the resistors and caps, I first removed the existing solder with solder braid, and then alternatingly heated both sides of the component while gently pressing against the side of the component with a pointy tool (it works best to press at the end that you’re soldering). At some point they start to move a bit, then repeat a few more times and it should be loose. Be careful not to force it, or you can damage the solder pad. (I did this once before I got the hang of it, luckily it just came loose and was not detached, I added a tiny botch wire anyway just in case.)
  3. I ordered all components from Digi-Key, using Polyphenylene Sulfide capacitors, see the shopping list I posted earlier in this thread. As a nice touch, I got all-Panasonic components :). To keep the price down I recommend ordering 10/20 of each, and you can share some sets with MSX users in your neighbourhood.

Conclusion

This is a very worthwhile fix to apply, it really has improved the sound quality very significantly. This is not just one of those things only audiophiles can appreciate. Really overall a big improvement on all accounts.

By ren

Paragon (1127)

ren's picture

30-11-2017, 22:31

Thanks for sharing, haven't listened yet, curious.
Could you fix the Content-Type your server is sending? They're now served as text/plain. (I'm lazy, want to listen in browser Wink)

By Grauw

Enlighted (7321)

Grauw's picture

30-11-2017, 22:36

Done!

By ren

Paragon (1127)

ren's picture

30-11-2017, 22:47

Cool

By KdL

Paragon (1109)

KdL's picture

02-12-2017, 07:43

Really nice!! Thanks Grauw. Smile

By Parn

Champion (304)

Parn's picture

02-12-2017, 13:13

@Grauw, thank you very much for taking the time to make such an extensive analysis. Having previously only listened to FRS' samples, I was already excited about this fix, and your analysis only makes me want it even more. I hope I can treat my turboR to this fix sooner than later. I also hope FRS can feel motivated by more positive feedback and consider fixes for other computers, too. Big smile

By sd_snatcher

Prophet (2775)

sd_snatcher's picture

04-12-2017, 12:55

Thank you for this detailed review, Grauw! It will help to clear the remaining doubts, so everyone can enjoy the beautiful soundtracks of the MSX games with the best possible quality on their real machines. Smile

Some friends insistently asked me for a similar fix for the Sony MSX2+ machines, so wait for some news about this soon.

By syn

Paragon (1852)

syn's picture

12-12-2017, 19:30

Grauw: Thanks for taking the time to upload the samples. To me it it doesn't change anything regarding what I said earlier in the other topic(s): Using the SFG filter values (which is, I assume part of FRS's proposed fix) makes the music sound imo too treble-heavy, making things sound shrill. Fort sounds ugly imo and the snaredrum of "Land of Flames, The Sky" sounds different and imo worse, lost part of its punch (I think the snare is psg noise and FM drum combined, and because now the FM part became so loud it drowns out the psg part).

The songs played with the WX filter values sound absolutely great though, with (imo) better balance between low/mid/high. Maybe this should indeed be the reference sound Wink (though obviously this conclusion was drawn by plainly listening and not by analyzing the sound using hard/software).

The other parts of the mod (volume balancing/leveling) seems fine, no problem with that. Gj on that FRS/sd_snatcher!

By Grauw

Enlighted (7321)

Grauw's picture

12-12-2017, 23:29

syn: Thanks for your opinion! I was hoping you would reply. Glad that the WX-type filter values I tried are to your liking. If you ever want to fix the audio on your turboR (if you have one, I forgot), then now you know what capacitor values to use to match your preference Smile.

Indeed a difference between the SFG and WX filters can be heard in that drum, I noticed that too; since the high end of the snare is filtered away more on the WX-type, it ends up sounding punchier. But at the same time on the WX-type everything sounds a bit muffled compared to the SFG-type. I’m a bit on the fence on which I like more as well, so I can understand if opinions go either way Smile. It’s the details.

Today I tried one more thing; I stacked two pairs of 2700pF capacitors to get a 6271 Hz OPLL-1 filter. Somewhere inbetween. Since I can’t really decide, am tired of keeping my turboR opened up, and would have to open up one of my sets prepared for others if I change it again, I’ll stick to this compromise :D.

p.s. I note there is no audible difference between the SFG and WX type filter settings for the other sound chips (PSG, SCC, etc.). Makes sense since there’s just half an octave difference on the global filter, and looking at the CX5MII neither SFG or WX-type values are out of the ordinary.

By Grauw

Enlighted (7321)

Grauw's picture

03-02-2018, 20:46

I brought some component kits for this sound fix to the Nijmegen fair, but maybe I should’ve announced it here since not many people were able to find it hidden away in the corner of my booth Smile.

Anyway, the kit consists of components for ST and GT, including the capacitors for both SFG and WX-type OPLL filter so you can decide for yourself which to use (see the recordings in my review above). The cost per kit is €10 including postage, Dutch people get priority. I have three sets left.

If you’re not confident applying the fix yourself and don’t mind visiting Utrecht, I can also modify your turboR for you. I can also fix the vertical jailbars on the turboR GT while I’m at it. (My agenda is a bit full for the coming month though, so maybe in march.)

By syn

Paragon (1852)

syn's picture

03-02-2018, 23:41

Grauw I forgot to post a follow up: When I heard that last sound clip (in december) I thought it would be the best settings/values Wink

I dont know if that would reflect my current opinion though (since its been so long ago and I dont feel like comparing them again right now Big smile )

By -Neo-

Champion (364)

-Neo-'s picture

04-02-2018, 10:08

Hi grauw, interested. Sent you an email.

By Grauw

Enlighted (7321)

Grauw's picture

04-02-2018, 17:20

The sets are gone now.

By syn

Paragon (1852)

syn's picture

06-02-2018, 23:51

grauw which filter value did you end up using as "final" ?

By alexito

Master (215)

alexito's picture

07-02-2018, 06:09

we need more Audio Fix Kit available please!!!!!!!!!! someone!!!!!!!!!!! Sad

By Grauw

Enlighted (7321)

Grauw's picture

07-02-2018, 09:29

syn wrote:

grauw which filter value did you end up using as "final" ?

Grauw wrote:

Today I tried one more thing; I stacked two pairs of 2700pF capacitors to get a 6271 Hz OPLL-1 filter. Somewhere inbetween. Since I can’t really decide, am tired of keeping my turboR opened up, and would have to open up one of my sets prepared for others if I change it again, I’ll stick to this compromise :D.

Didn’t change it since then.

By -Neo-

Champion (364)

-Neo-'s picture

05-03-2018, 00:54

Thanks Grauw for fixing my ST and GT. I am very happy with it. A very big improvement! Enjoying Space Manbow and XAK tunes at the moment on the GT through VGMPLAY. Also the removal of the jailbars on my screen makes my Turbo R GT so much better. Thanks again and also sd_snatcher for inventing this mod.

By KdL

Paragon (1109)

KdL's picture

29-03-2018, 04:42

My idea on the 1st stage of Space Manbow and this audio fix...

Probably the sound was programmed using the original machines with bad mixers.
The programmers chose the perceived audio volume during the design phases of game.
The conclusion is drawn that the very high PSG volume in not correct for this game.
Not so bad mind you, but it should be a little lower in my opinion.

By KdL

Paragon (1109)

KdL's picture

13-05-2018, 21:32

By Pencioner

Hero (634)

Pencioner's picture

13-05-2018, 23:01

That sounds really well, now looking forward to receive my Zemmiz Neo after fix (sent back yesterday)

Great job! Thanks! Wink

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