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I must have got some concept of how computer audio pipeline works WRONG for sure, so please point me out!

I'm not an audio enginner but I'm trying to balance sounds for my game. The game uses XNA so XACT auditioning tool will be used to control audio content.

I'm now considering what is the 'normal' volume of my game? Currently I go listen to a music at my comfortable level (Volume settings of computer is at 25% and volume setting of foobar2000 I used to listen is at 100%) and try to make overall volume of my game at this level. Is I am doing right if I used this kind of reference for my game? The reference music I listened to are well-mastered by commercial studio of course, so the volume will be around 0dB, correct?

Now here is the problem, I think I should make my total sound of my game not exceeding 0dB or that will be clipping.

I'm developing a side scrolling game. I have one weapon which produce loud continuous sound. Currently when I set the in-game SFX setting to 100% the volume is alright, but I think the default SFX setting have to be about 70% so player have a choice of increase or decrease the volume. (correct?) Well, 100% sounds alright now so if I set the default to 70% it will be too quiet. So after I set the default in-game SFX level to 70% I went to XACT and increase the mixer of my SFX category from 0dB to 6dB. So my 70% will be equivalent to my old 100% and allowing player to go louder.

The problem arises, when I'm shooting that loud weapon and press a button to bring up pause screen. Normally the 'ding' SFX will be played when pause, but I've noticed that my 'ding' sound is noticeably quieter when pause the game while firing weapon! If I'm not doing anything the 'ding' sound will be louder. This is not happening with my previous 100% sound and 0dB gain on my SFX category setting. Is this called clipping? If I were to describe, the 'ding' sound were muffled by shot sound.

When I turned down a volume of computer the clipping is still there. It's just hearing the problem quieter. This leads me to thinking that the clipping is happening in game application before sending out to computer. The computer has more headroom? If I listen to lady gaga while playing my clipped game sound, my lady gaga will be in the perfect form? (Well, I don't really listened to lady gaga but that's an example)

Now talking about BGM. With my understanding of clipping I think game BGM have to be much lower than 0dB (unlike track for listening) because you have to leave some room for SFX to add up to 0dB is that correct? If that so can I calculate what my average SFX volume should be based on average BGM volume so they add up nicely to 0dB?

The solution I can think of is to mix the overall sound in the game in somewhat low volume (Even in 100% BGM and SFX in-game settings) and then let player turn up the volume of their computer (or TV) them self. With this setting every time playing this game you must turn up the volume... which I think is not right.

How come many commercial games that fires a lot of weapons and each SFX is still in their correct form?

The XACT tool supports adjusting the gain level. Is it the best practice that I mix all SFX in my games around 0dB and then setting negative gain in XACT? (and never set a positive gain)

It's a lot of question here but I don't have any luck searching for solution so far.. Thanks!

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I'm now considering what is the 'normal' volume of my game? Currently I go listen to a music at my comfortable level (Volume settings of computer is at 25% and volume setting of foobar2000 I used to listen is at 100%) and try to make overall volume of my game at this level. Is I am doing right if I used this kind of reference for my game? The reference music I listened to are well-mastered by commercial studio of course, so the volume will be around 0dB, correct?

I don't fully understand what you're saying. But basically, if you can find a reference and your listening is uncalibrated (i.e. you don't have a standard listening level at which you work everything), then you'll use the reference to gain a reference point for the mix and loudness, but forget the numbers. However, you should use a reference that's realistic, so don't use something that's been mastered red hot or which is a completely different style that you're doing, because it may not be what you're looking for. Generally, use your ears!

Now here is the problem, I think I should make my total sound of my game not exceeding 0dB or that will be clipping.

Yes sure. It should be limited to / not go over 0.0dBFS, or e.g. -0.3dBFS to prevent overloading.

I'm developing a side scrolling game. I have one weapon which produce loud continuous sound. Currently when I set the in-game SFX setting to 100% the volume is alright, but I think the default SFX setting have to be about 70% so player have a choice of increase or decrease the volume. (correct?) Well, 100% sounds alright now so if I set the default to 70% it will be too quiet. So after I set the default in-game SFX level to 70% I went to XACT and increase the mixer of my SFX category from 0dB to 6dB. So my 70% will be equivalent to my old 100% and allowing player to go louder.

No, you shouldn't leave digital headroom unused. A finished mix should have its loudest parts at 0.0dBFS or very close to that, not lower, because that would be leaving digital headroom unused and it's guaranteed to be quieter than everything else, so it can't match with the sound level of other media. And you don't want the listener to have to drastically adjust the system volume, when switching from game to game, media to media. Sure, the listener can adjust the system volume, but that's a separate thing from setting the maximum level of a sound mix, which should use all available headroom in its loudest parts.

The problem arises, when I'm shooting that loud weapon and press a button to bring up pause screen. Normally the 'ding' SFX will be played when pause, but I've noticed that my 'ding' sound is noticeably quieter when pause the game while firing weapon! If I'm not doing anything the 'ding' sound will be louder. This is not happening with my previous 100% sound and 0dB gain on my SFX category setting. Is this called clipping? If I were to describe, the 'ding' sound were muffled by shot sound.

It sounds like it's clipping or hitting to a master limiter, which forces the overloaded part of the sound down. Excessive clipping is accompanied by harsh distortion and you can ALWAYS see it from any volume meter (if it's peaking at full or there's a red warning light, then it's clipping or has been clipped).

When I turned down a volume of computer the clipping is still there. It's just hearing the problem quieter. This leads me to thinking that the clipping is happening in game application before sending out to computer. The computer has more headroom? If I listen to lady gaga while playing my clipped game sound, my lady gaga will be in the perfect form? (Well, I don't really listened to lady gaga but that's an example)

Yes. "Clipping" never occurs after the sound has left the computer system, it happens when it's captured or before it's output. Precisely it happens, because the sound level exceeds the highest value that can be represented digitally and the amplitude values that go over that maximum value are simply truncated to the maximum value, which then distorts the overall signal. Practically clipping is created if recording at a too high level or by letting the sound digitally exceed the maximum level (0.0dBFS in level meters). You should not clip the audio, but keep it under 0.0dBFS or limited to 0.0dBFS in all cases, but not over 0.0dBFS, because that part going over 0.0dBFS is clipped.

Now talking about BGM. With my understanding of clipping I think game BGM have to be much lower than 0dB (unlike track for listening) because you have to leave some room for SFX to add up to 0dB is that correct? If that so can I calculate what my average SFX volume should be based on average BGM volume so they add up nicely to 0dB?

Yes. You need to balance all sounds that you're adding to a mix so that they use the headroom wisely and don't overload/clip the system. Therefore you place the sounds that are to be loudest to be the loudest and balance other sounds to accompany them at lower levels. However, there's much much more to mixing (EQ, dynamics control etc.) than balancing the volumes of tracks/sounds, but setting the basic balance of tracks/sounds is a good start.

The solution I can think of is to mix the overall sound in the game in somewhat low volume (Even in 100% BGM and SFX in-game settings) and then let player turn up the volume of their computer (or TV) them self. With this setting every time playing this game you must turn up the volume... which I think is not right.

You should mix at a level where you know what kind of mix you're targeting, i.e. the listening level helps you know how to mix the sound. This is also why you can use reference audio/mixes, because you can compare your mix to those and hear whether what you're doing is in the ballpark of other reasonably similar mixes.

How come many commercial games that fires a lot of weapons and each SFX is still in their correct form?

Because they've been mixed so that they maximize clarity and impact without overloading the system. That's what sound mixing is about. Making the available sounds sound clear and fitting them together in the mix and using the limited volume range and frequency range in a way that maximizes clarity and impact.

The XACT tool supports adjusting the gain level. Is it the best practice that I mix all SFX in my games around 0dB and then setting negative gain in XACT? (and never set a positive gain)

You can do either way, either premixing the sound before bringing it to XACT or setting the levels in XACT. Most game audio people juggle between the implementation tool and a DAW, because you cannot do many adjustments in the implementation tools or it's cumbersome, so it's better to have the mix balance in the ballpark, before importing them to implementation tool, because all you can do there is adjust volume and effects.

  • Thanks! I'd like to ask another question. Is there any practice of making game SFX somewhat bass-less? I heard when DJ mixing music together they had to EQ the bass down so kick drum of 2 songs don't overlap. Is this the case of mixing BGM and SFX in a game? BGM is a rock tune so all frequency are used. Should I reduce the bass of all my SFX? – 5argon Apr 30 '13 at 3:19
  • @Sargon Basically you use an equalizer to layer different sounds and tracks together. Bring down the frequencies that annoy you or mask other sounds or possibly boost the frequencies that you want more. I don't know if there's other practice than just trying it yourself. I recommend making equalization when all the tracks that will be played together are playing together. Then you'll decide, in the case of bass frequencies, which sounds should have bass and which sounds could do with less bass, and equalize so that the tracks fit together well. – Internet Human Apr 30 '13 at 11:55
  • Remember that the volume balance and volume dynamics also affect what you're hearing. It's not always the case of equalizing, but rather just bringing sounds down in volume or balancing them differently, and then possibly equalizing, if necessary. What all mixing boils down to is understanding the basic concepts of volume and volume changes, frequencies and auditory masking, panning and space and then combining tracks and sounds together so that they fit together. – Internet Human Apr 30 '13 at 13:09

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