Every year or two I decide to tune my brace height and go through the whole shoot/listen/add a few twists/repeat scenario. Occasionally some high or low value causes a bit of a rattle, but other than that I've never really noticed a difference in sound as I go through the full range in increments of a few mm. Every tuning guide, video, and forum post makes it sound like there's one (or two) obvious sweet spots where everything is noticeably quieter, but embarassingly I've never noticed this. Could be my ears (I do play the viola, after all), or that the time to change from one brace height to the next is enough for me to forget the sound of the previous setting when comparing it to the new one, or that I've somehow got the one bow immune to string length. So I've generally then picked a nice looking number and gotten on with other things. I'm happy with my grouping and the sound of my bow, and wouldn't necessarily choose the quietest brace height if i could find it anyway. Setup is a standard olympic recurve with lightweight arrows that are bareshaft tuned. Only anomaly would be that it's a fiberbow riser with no extender.
Still, it's an itch that needs to be scratched, so this time I used a much wider range (20.5-25 cm for 68" bow) and started with a 5 twist increment (2mm at a time at 20.5, 6mm at 25), recorded each shot from a constant distance ( after an initial shot to settle the limbs), and edited out the clicker and target noises. So I can now listen to several brace heights side by side. I've linked to the audio from one test here. My ears are none the wiser however, and when I graph the shot noise (amplitude adjusted for frequency-dependent perceived loudness) I just get a slight decrease as brace height increases, which is expected due to the change in stored energy. I've repeated the test with a finer increment and more shots and different tiller settings but get very similar results. In contrast, when I shot a 605gr arrow instead of my regular 280gr ACE, I can clearly hear how quiet the heavy arrow is both while I'm shooting and in the recording, and the average calculated noise is about a third less. Similarly, I can hear the difference when I grip the bow or pluck the release.
Does you have a clear audible quietest point in brace height? If so, how wide is this minimum and how much quieter does it seem to be relative to neighbouring settings? I haven't found any other audio or videos online showing different brace heights on the same setup and it would be interesting to see how audible the effect can be.
Still, it's an itch that needs to be scratched, so this time I used a much wider range (20.5-25 cm for 68" bow) and started with a 5 twist increment (2mm at a time at 20.5, 6mm at 25), recorded each shot from a constant distance ( after an initial shot to settle the limbs), and edited out the clicker and target noises. So I can now listen to several brace heights side by side. I've linked to the audio from one test here. My ears are none the wiser however, and when I graph the shot noise (amplitude adjusted for frequency-dependent perceived loudness) I just get a slight decrease as brace height increases, which is expected due to the change in stored energy. I've repeated the test with a finer increment and more shots and different tiller settings but get very similar results. In contrast, when I shot a 605gr arrow instead of my regular 280gr ACE, I can clearly hear how quiet the heavy arrow is both while I'm shooting and in the recording, and the average calculated noise is about a third less. Similarly, I can hear the difference when I grip the bow or pluck the release.
Does you have a clear audible quietest point in brace height? If so, how wide is this minimum and how much quieter does it seem to be relative to neighbouring settings? I haven't found any other audio or videos online showing different brace heights on the same setup and it would be interesting to see how audible the effect can be.