Here's an idea for an article: a guide to effective mufflers or something like that. Based on actual knowledge and not urban myths
Here's what I know about this.
- Airflow needs nice pathways, no extremely sharp turns, etc. or it may cause too much airflow resistance.
- No straight paths from sound source to outside world. Make the sound bounce around.
- Add sound absorbing material inside the muffler. Each time the sound bounces of a wall that's covered with sound absorbing material some of it is absorbed.
- Need different sized chambers in sequence to widen the frequency band(muffler silences wider range of sound frequencies). This is where some real knowledge and knowhow would come helpful. What sizes and shapes the chambers should be? What kind of entry and exit holes work best and their positioning?