Brace height tuning problems

[Wandering Archer]

So, I just got a new skinny string for my Abbott longbow and thought I'd tune the brace height based on noise before I add any silencers.
I downloaded a noise meter app for this purpose, since I can't go by ear. In tests, the app was proven pretty accurate, but regardless, I just need it as a reference from shot to shot, so accuracy isn't really that important here, just consistency.

Well, anyways, I started off at the recommended BH from Abbott himself at 6.2"(actually 6 3/8, but I was using a scale with 1/10 markings...)

Shot 3-4 arrows, and averaged 82dBa.

increased the braceheight to 6.5, 6.8, etc. I was able to get it down to an average of 80dBa, but that was it. It didn't seem to change at all, no matter what the brace height, and I went above 7".

My phone was about 2' off the ground right under the bow.

Any thoughts guys? I just went ahead and put silencers on. Haven't taken any readings after the silencers, but I figured the bh didn't really matter for this bow, as far as noise is concerned, so I just put it back to 6.5".

And I was all excited to geek out over this... Is there a disappointment smiley?

[Bladepeek]

Actually, I believe 3db is roughly double the sound level, so if you decreased the sound level by 2db, that's still a substantial amount.

Have you had a chance to measure the sound with the new string silencers? And what gpp are you shooting for arrows?

[Wandering Archer]

Really? Seemed like it wasn't that big of a difference. I'll have to double check my numbers, but I think I hit 79dba at 6.5 and every bh from there up stayed right at about 80-82dba. So maybe the 79dba is the sweet spot?

I haven't shot with silencers yet. I'm going to do the same test with silencers when I get a chance.

Not sure what the gpp of the arrows. 47# longbow, I was shooting two cedar arrows with 190gr. points, but I'm planning to tune to 300gr. points when I get my new shafts.

[Paul_R]

Actually it's the pressure that doubles every 3db but the point is well made. 3db is a big difference.

[The Whittler]

Wow and I thought compound shooters were high teck. Just kidding, to each their own.

[Wandering Archer]

Originally posted by The Whittler:
Wow and I thought compound shooters were high teck. Just kidding, to each their own.

well, I'm an engineer... I can't help but make everything more complicated than it needs to be, lol.

Actually, up until now, Ive always just shot 3D, so Ive never even considered noise. Im trying to gear up for hunting, and I see these threads about bow noise, arrow noise, etc. and it's always totally subjective, and I cant hear any difference. so I said to myself, "we have the technology..."

[Bjorn]

Was the spec for the Abbott-6.2"-based on a Dacron string? If so, you should be going below that brace height not above-at least that is what Jay St. Charles told me.

[Wandering Archer]

Originally posted by Bjorn:
Was the spec for the Abbott-6.2"-based on a Dacron string? If so, you should be going below that brace height not above-at least that is what Jay St. Charles told me.

The posts I've seen from Abbott and other have said 6 3/8". His bows come with FF strings. All I did was go to an 8 strand. Maybe I should try going lower? Just seemed like 6 3/8" was already pretty low.