Boosting Sound files

I know this isn't exactly building, but it doesn't fit into the other forums either. I want to upload sound files, but when I do they are very quiet. I tried recording them as loud as possible and then used audacity to try to boost them, but then it cuts off the peaks and sounds funny. Does anyone have any program recommendations to boost wav files -- preferably free, or know specific steps in audacity to boost sound files?

I'm using them in objects and set the script to play at 1 loudness, which should be the loudest, but its really not anywhere near loud enough.

Thanks,
Prismatica

If on windows:

Open the sound recorder (Start>All Programs>Accessories>Entertainment>Sound Recorder)

And then open the file. Go to 'effects' and hit 'Increase Volume(by 25%)'


Tada! It's 25% louder!

(Repeat if wanted)

This is what's known in audio terms as "clipping". When the amplitude of sound waves (loudness) exceeds the maximum tolerance for your audio device, the peaks of the waves get cut off, and the result is a distorted sound. (Distortion/overdrive effects for electric guitar, by the way, are the result of intentionally doing this. It's a controlled overload. When you turn on that distortion pedal, you're activating an audio circuit with a very low amplitude threshold. The signal level from the guitar is more than enough to overload it, so the sound distorts. Yes, I'm an audio geek, and I find this stuff interesting. )

The maximum unclipped levels that your audio editing program is showing you are the highest "safe" input levels for typical devices such as CD players, stereo systems, iPods, computer sound cards, etc. If your sound is loud enough to clip, that's as loud it can safely get. Further attempts to up the volume will only further clip the waves, making the distortion worse. What you want to do, always, is make the sound as loud as it can get without clipping, no louder.

If your sound has a high dynamic range, meaning it's got both very loud parts and very quite parts, it can be a bit of a challenge to find a good level. Better audio editing programs usually have tools to allow you to narrow the dynamic range, bringing the extremes of loudness and softness more toward the middle. You can then safely increase the volume of the whole thing. The result is a more boring, more flat, version of the sound, but at least you can hear it all. Basically, you get to bring the bottom up without overloading the top. I don't know if Audacity has these kinds of tools or not (or if it even matters, since you didn't specify whether or not dynamic range was part of the problem).


Anyway, there are two main reason sounds seem quieter in SL than in other programs. First, SL's output level is fairly low. I have no idea why. But whatever the reason, there's no way around it. Take any sound with any given input level, play it through SL, and the output will be noticeably quieter than if it were played through a dedicated audio program.

Second is distance falloff. The further your camera is from the source of a sound, the quieter the sound will seem. You can adjust the falloff ratio in your preferences if you want sound levels to be more consistent.



That's only going to work losslessly until the sound reaches maximum input level. After that, it will start to clip. From that point on, distortion will get worse with each increase.

Both responses are very interesting and useful. I used the info on the windows increaser to make it louder sufficient as those are small drums. But I think for the larger ones I want to make I will try to record the sound quietly, which in theory should keep the range more even and thus be able to be more applified I hope.

Its got to be possible, I've seen some nice drums with clear loud sound in SL.

Thanks!

With digital recording you want to record as high a signal as you can without peaking. You'll get a lot better quality making loud sounds quieter than trying to boost quiet ones.

Have a play with the compressor effect in audacity. This will let you boost quieter portions without blowing out the peaks.

The exact steps are going to vary depending on the type of sound, but for drums you'll probably find a bit of bass boost will help give them a little more kick too.

An expander can boost the dynamic range of the sounds too. There's one for audacity in the Ladspa plugins pack.

http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#tth_sEc2.93

You'll find that that's not a good way to go. As Domino said, you want to record as loud as you can without peaking or clipping. If you record quietly, you create two problems. First, you get much lower sound quality, since there's less signal to work with. Second, no matter how good a recording is, there's always some degree of noise. When you increase the volume in post, you end up boosting the signal and the noise at the same time. The louder you make the previously quiet sound, the more noticeable the noise becomes.

Good quality recording is first and foremost about tracking at proper levels. The best producer I ever worked with once told me this: "Track it well, and it mixes itself". In other words, the more full the original recording, the less you'll have to mess with it. That means recording at proper volume right from the start.

I'm pleased to hear Audacity has a compressor. If it works well, you should be able to narrow the dynamics significantly. For recording vocals, drums, bass guitar, and other highly dynamic instruments, good compression is often vital.

You may want to get a friend to double check for you. I do a fair bit of sound and on my tower its always low. But it was shocking when I logged in on my laptop and it was so loud. Like chaotic loud. It may just be your computer as well.

it could be my computer some, but I've had a few people complain about it.

I'm sure my mic doesn't help. before I used a 10 year old+ mic, which recently died, but my headset for voice on SL seems to have a major issue making things really quiet.

Any tips for working with a compressor with Audacity?

This explains compression in a general way:

http://www.saecollege.de/reference_material/pages/Compression.htm

This is an Audacity specific example use:

http://www.linux.com/articles/52956

There's a griefer trick with gestures and other sound players to trigger one sound multiple times at the same time. The sound mixing method in SL is additive, so as long as the sound is cached the result will be one big loud sound. But, really, how loud do you want to be? I've been around fountains that are just abusive of the area around them and all the noise discourages me from sticking around. (>_< .... (^_^)y