Hi all!
This is something that I asked myself long ago but I didn't have any challenge about it until now.
I'm working on a PC vintage ethnic game, and I'm making Music and SFX.
The soundtrack is big, and it turns to be in different keys each track, so when I have to make SFX with different hierarchy (for example, little things, little power ups, with big and important items and powers, etc.) I found that when I want to make this kind of musical or complex item SFX in one track or another it'll crash to dissonance in some of the levels.
Having this problem I found that I worked for a lot of little games (with for example one track or two) in which I could fit the keys of the SFX and the soundtrack. But in this case I don't know if I have to let the developers code some kind of fade (as a side chain with the music) when the SFX is going on or If it has to be the music down, or if I have to change the esence of the sound design (maybe making inharmonic complex item sounds?).
Thanks in advance, I'll try to figure it out but If you have some advice I'll learn something more.
Best regards for all,
Hernán
About SFX clashing Music
To make the SFX stand out you could use Ducking to temporarily lower the music volume when there are SFX. As for harmonics between sfx and music, perhaps if all the music is in a way related through key and have the SFX play on the similarities between these.
Sometimes there is no problem when music is clashing with SFX. It depends on what type of SFX you create. It is hard to give you a proper advice without hearing your music/SFX. There are thousands of variations.
You can make atonal or non-musical sound effects for example. But there are SFX that clash with music harmony but cause no earache 
Look for another game examples.
http://www.youtube.com/watch?feature=player_detailpage&v=LMYY-FLtCKw#t=125
This game has lots of tonal SFX. And no one is clashing with music so much.
A couple quick comments
It is certainly possible to have separate versions of your SFX that match the keys of the various background musics. That said, it's improbable your programmer would want to take the time or resources to support that.
As mentioned, you might get the programmers to be able to duck the music when you play sfx
But is it possible your music is just mixed too high?
Another thought-- re-orchestrate your music so it isn't quite so dense ("big" is the word you used). One of the challenges in music for media is making sure the music leaves enough room for the SFX. I recall a talk by the team who did Star Trek III-- at one point everybody is on the Genesis planet which is is full of volcanos and earthquakes.. The sound designer talked about he and the composer would frequently meet to discuss the overall audio for the film. For that particular scene, he knew he'd have lots of low frequency rumblings, boulders crashing, etc. So the composer didn't write much for the string basses or low brass for that scene, which left room for the low frequency sound effects...
Another thought-- re-orchestrate your music so it isn't quite so dense ("big" is the word you used). One of the challenges in music for media is making sure the music leaves enough room for the SFX
Yes! Exactly. This is the first thing you must think about when you start composing music.
Hi all, thank you for your answers and you time.
Well, about what Brian said, actually I would think the music taking care of the SFX but the developer gave me the SFX after I made 3/4 of the Soundtrack, actually I was in charge of music not the SFX.
Although I take a lot of your advices, I'll change some SFX to inharmonic sounds, the ones that I can't I'll study the situations and see if I can have one tonallity or two this might be tricky since it's ethnic music (arabic scales, macaams, etc). In case I can't I'll be using the ducking, as it was the idea I had first.
I'll let you know when it's all finished,
Thanks again,
Hernán
I was just experimenting with this in the studio. There were a couple of things that were interesting:
- Cutting some bass out of most of the sound effects and apply a low pass filter to the music instead of ducking the volume kept the energy levels up. The music was fairly tough electronica.
- Delaying the less critical sounds to put them in time with the music was exciting.
B.
