Amping Audio for CD-Rs: A Guide

[SamIAm]

Since I'm re-burning a bunch of stuff using Taiyo Yuden discs that my Super CD seems to like, I thought I would post a guide about doing something that I frankly can no longer enjoy many PCE games without: Pre-amplifying audio redbook tracks to change the music/sound-effect volume balance.

Many shooters in particular suffer from sound-effects that are too loud, including some of the very best on the system. Gate of Thunder has a soundtrack that's been famous since day one, but be honest: can you hear it behind the sound-effects in the game ? Then there's specific sound-effects like certain weapons in Sapphire, the homing weapon in Terraforming, or the king of them all, the yellow beam weapon in Rayxanber III. At unaltered volume, these are borderline unbearable, IMHO.

Well, good news! If you are willing to play CD-Rs, you can nip this problem in the bud by following this simple guide:

(If you're using an ISO/WAV rip, skip to #5)

1. Download and run the free version of IsoBuster.

2. Click File -> Open Image File, and browse to your cue sheet.

3. Right click "Session 1" (or "CD"), then click "Extract User Data" as in the pic below.

https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard02_zpsjlampx8h.jpg

4. Choose a place to put the files, click OK, and let it export everything. Now close IsoBuster.

========================

5. Open Audacity. Click File -> Import -> Audio... as in the pic below.

https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard03_zpsotwocfmf.jpg

6. Browse to your image and select all of the audio files only. Go ahead and skip Track 01, too. When you click OK, it will take a minute to load everything up.

7. For this example, I am using Cotton (US). Now, just look at how tiny the original waveform is. Without introducing any quality loss, we can amplify it significantly. The key is not doing it too much in order to avoid hitting the floor/ceiling, which will clip the waveform.

https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard05_zpsa6yd7vqq.jpg

8. Hit Ctrl+A to select everything. Then, click Effects -> Amplify. Select "Allow Clipping" (trust me). Enter any old number you feel like, click OK, then let it process things. I'll go ahead and "turn it up to 11" here. (Audacity might seem like it's frozen after you click OK, but don't worry, it's just working.)

https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard06_zpsdeypu6s1.jpg


https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard07_zpsuhsesfky.jpg

The result:

https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard08_zpsdis3hxhd.jpg

9. Now that's what I'm talking about! But wait, you might be saying...it looks like the waveform is clipping in a couple of spots there. Well, yes it is. However, if you listen to the track, you will understand that those are basically just drum hits, and the clipping lasts only a super-small fraction of a second. It's not even easy to distinguish in a side-by-side comparison. For me personally, that tiny bit of quality loss is a small price to pay to be able to turn up the volume a lot and hear the music during gameplay.

However, it is always a good idea to browse through all the tracks and make sure none of them have any bad clipping. Look at Track 26 here, which in this game stands out to me as the most vulnerable:

https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard09_zpstbnmm2nz.jpg

That's kind of pushing it. Most of the clipped parts are still just drum hits, but if you look closely, there is some prolonged clipping in there. All right, then, let's hit Ctrl+Z to undo the amplification, then click Effects -> Amplify again and enter a smaller number like 9. Here's what the same track looks like with that level of amplification:

https://i171.photobucket.com/albums/u305/sirsinnes/Clipboard10_zpss8pc2aef.jpg

Okey dokey, that's back in the acceptable range. I suppose I'll add here that you're probably not going to notice much of a difference unless you amplify things by at least a value of 4. 

10. Basically, you're going to want to repeat this process of trying different amplification levels, browsing to look for bad clipping, and honing in on an optimal audio level. For Cotton here, I actually decided 10 was good for me. I love the music in this game, and I don't give a rat's about tiny sound effects or a teeny bit of drum clipping.

11. Finally, when you're ready, click File -> Export Multiple... and set your filetype (WAV) and your destination (original folder works well). Audacity might save your original files with "-old" added as a suffix if you try to overwrite them; go ahead and delete all of those. Finally, open up TOCFixer, have it check your new ISO/WAV set and fix it. The WAVs post Audacity-processing might be just a few bytes larger, but don't worry; let TOCFixer do its job and everything will be fine. It'll give you a cue sheet, which you can burn and enjoy.

I burned this version of Cotton, and while the change in the waveform may look drastic, the sound effects are still very easy to hear. I'm pleased with the results.

And that's all! Hope someone gets something out of this!

[ccovell]

Yes, a cool guide.  You can also change the equalization of the music tracks, since some games have been mastered with the bass killed off and too much midrange (NEXZR, for one.)  Using the FFT, you can see where the audio spectrum has dips or drops off too quickly.

[esteban]

 I love this guide.

If folks started doing this, we should share them.

I would love to host all the "remastered" Red Book soundtracks along with the original, unadulterated versions:

https://archives.tg-16.com/music_database.htm

Yes, a cool guide.  You can also change the equalization of the music tracks, since some games have been mastered with the bass killed off and too much midrange (NEXZR, for one.)  Using the FFT, you can see where the audio spectrum has dips or drops off too quickly.

Yes, far too many games have been mastered this way...

I always wondered if this was intentional: "make sure the audio mix sounds good on standard speaker(s) in average consumer TV" ...the baseline.

[CrackTiger]

I think that Duos and CD-ROM combos might have a different balance of audio, because of all the similar effects/bgm balance issues I've heard over the years, most weren't close to as extreme for me as people described.

Although it might also just be the difference in stereo systems people use.

[esteban]

I think that Duos and CD-ROM combos might have a different balance of audio, because of all the similar effects/bgm balance issues I've heard over the years, most weren't close to as extreme for me as people described.

Although it might also just be the difference in stereo systems people use.

It is hard for me to be objective about this because I have been using TG-16 + home stereo from the very beginning, but I would usually have "loudness" on (and bass cranked up).

When playing music/games at a low volume, using loudness/cranking up base is useful, but you are *supposed* to turn off loudness/crank down the bass when blasting audio at a decent volume...for some CD games, however, the bass was incredibly weak at normal listening volumes.

I corrected for this by adjusting bass/treble on stereo+speakers...but my poor TV's speaker in 1989 didn't offer any fine-tuning options (not that it would have made much of a difference).

[SamIAm]

Incoming comparisons via real hardware (Super CD and Supergrafx):

Original: dropboxusercontent.com/u/32377930/Original.mp3
(from a real CD of the Japanese version of Cotton)

Amped: dropboxusercontent.com/u/32377930/Amped.mp3
(Upped by 10 in Audacity)

These were taken from the headphone jack on my TV connected directly to my laptop mic input. The TV impacts the sound slightly, but the difference in balance is unaffected.

I think that Duos and CD-ROM combos might have a different balance of audio, because of all the similar effects/bgm balance issues I've heard over the years, most weren't close to as extreme for me as people described.

Although it might also just be the difference in stereo systems people use.

This is something much too prevalent to be the result of external stereo equalization weirdness. Even Mednafen has noticed:

Obnoxious Sound Effects in CD Games

Many CD games have awesome music, but it is drowned out by excessively loud obnoxious sound effects. This can be partially remedied by altering the pce.cdpsgvolume and pce.adpcmvolume settings, try say a value of 50, but doing so may cause issues with cutscenes and PSG music-only sections.


It's possible that different versions of the CD system are mixing things differently on an internal level...but I can say from here that a Duo-RX and a Super CD sound the same.

If you would like to record any of your games from any of your systems, I would be happy to record a counterpart so we could do a comparison.

One thing I've noticed after looking at a lot of redbook audio waveforms of many PCE games is that almost none of them are really large. I wonder if every game got "normalized" somewhere along the road to mass production, and if there were some cases where the original devs weren't able to get the kind of balance they intended.

[esteban]

ON HARDWARE AUDIO MIXING/OUTPUT:

I recall one of the tech gurus (bonk-Bonknuts-tomeithous?) stating that IFU/TG-CD mixed CD audio down to mono and then output mono? (I know that sounds both crazy and totally disappointing). Or did it mix down PSG+ADPCM+Cd audio down to mono?

Depressing, if true, since I like the earliest hardware configurations.

[roflmao]

This is a neat tutorial. If I get around to tinkering, I'll send them your way, este!

[GohanX]

ON HARDWARE AUDIO MIXING/OUTPUT:

I recall one of the tech gurus (bonk-Bonknuts-tomeithous?) stating that IFU/TG-CD mixed CD audio down to mono and then output mono? (I know that sounds both crazy and totally disappointing). Or did it mix down PSG+ADPCM+Cd audio down to mono?

Depressing, if true, since I like the earliest hardware configurations.

If you're pulling the audio from the system then yeah, it's mono. If you use the IFU/CD Dock's RCA jacks you get glorious stereo.

[tknjin]

This is really cool, however, I am curious since you are doing pc engine, and with the discovery of the saturn(which are my 2 fav systems) could you do this on other systems as well?  Like the sega cd, playstation 1 of sorts.  Now, I am quite fascinated by this

[SamIAm]

If it's a plain redbook CD track (ie it will play in an audio CD player), you can apply this process and make it louder regardless of the system.

If it's not a redbook track, it becomes exponentially more difficult.

Also, a lot of games have sound effects that are a little too loud yet the music cannot be amplified much without introducing bad clipping. Hyper Duel on the Saturn is one such example. You can amplify it a little, but not "enough" in my opinion.

[esteban]

ON HARDWARE AUDIO MIXING/OUTPUT:

I recall one of the tech gurus (bonk-Bonknuts-tomeithous?) stating that IFU/TG-CD mixed CD audio down to mono and then output mono? (I know that sounds both crazy and totally disappointing). Or did it mix down PSG+ADPCM+Cd audio down to mono?

Depressing, if true, since I like the earliest hardware configurations.

If you're pulling the audio from the system then yeah, it's mono. If you use the IFU/CD Dock's RCA jacks you get glorious stereo.

Aha!

Thank you.

I am glad I was mistaken...

[destructive cactus]

Cool tutorial! Will definitely try this.

It might be worth it to look into using 'Compressor' to SLIGHTLY (don't use a very high ratio at all) squash those drum hit peaks before amplifying (i.e. make-up gain). Then, there'll be no clipping at all.

[NightWolve]

Well done guide, Sam. I learned about this problem some time back when I noticed Ys IV tracks were REALLY REALLY hard to amplify and had a talk about this with Justus Johnston (my 1st Ys IV Dub manager).

I eventually learned how to use Audacity to normalize/amplify and handle the clipping to repeatedly try amplifying more... It's interesting, the industry used to burn really low pre-amped audio but then later in the 90's they went in the opposite direction. NEC PCE CDs were in that really low pre-amp level practice in seems. But yeah, I did a lot of work some years back just to make these Ys MP3s for my music player here:

https://www.pcengine-fx.com/catalog/
https://www.pcengine-fx.com/audio/
https://www.ysutopia.net/audio/

Anyway, that would be an interesting feature for my TurboRip app, to auto-normalize a wave upon extraction. If that's an easy function, might be worth considering to import it and add a switch for use while ripping.