I'm with Andy here. A well set
compressor should do it. If you don't know how to set a
compressor I'll see if I can give a quick rundown, though learning from experience will do loads more. The first thing to remember when you're setting a
compressor is if you don't want it to be very audible that it is compressed, as it gives a "smashed" sound to the music. Most FM radio stations broadcast the music heavily compressed, and as a result when the song should get louder it just sounds like it got turned down. That is not the goal in most cases. In most cases you want to use the
compressor to take the loudest parts of sound and make them not as loud so that you can turn everything else up. Typically the knobs on a
compressor I worry about the most are the
threshold, the ratio, and the attack. The
threshold tells the
compressor how loud the sound should be before it does anything. The ratio tells the
compressor how much it should turn the signal down once it hits the
threshold. The attack tells the
compressor how long the audio has to be over the
threshold before it takes
effect. The
threshold will be expressed in dB. The ratio will be expressed as 1:1.4 or 1:64 or something like that. The attack will be .2ms or something similar. It may be as high as 2000ms (2s) or more. There is no general setting for a
compressor. Just
play around with the knobs till you get what sounds right. Try to ensure it doesn't sound smashed.
Also just on a side note you said they were peaks. Are they short peaks, or are they loud areas of sound, followed by softer areas. If they are short peaks I would consider a
limiter instead. A
limiter is a specific kind of
compressor with a 1:∞ (infinity). A
limiter will get you a sound closer to what the radio uses, but it has its place where it is useful. As for adjusting it in SoundForge, I can't help you there because I haven't used it. If its a decent audio program it will have a
compressor on it. If you don't find something under
compressor it may be listed under dynamics also.
