Barrel noise comparison

[Otnasir]

Forgive me if this is the wrong place to post.

Recently bought some core barrel tip for the freak xl. These tips vary in inside diameter, like the inserts.

I also bought a decibel meeter. Placed my emf100 on a gun stand with the decibel meter and chrono graph in fixed locations near by.

I tested a standard freak xl, a carbon fiber freak xl "gog brand", a freak xl with core tip 683, and the stock barrel of an empire sniper. I used the same control bore (677) across all the freaks and a 675 back on the sniper barrel. Here were my findings.

I left the guns velocity alone untill the second core test.

Carbon fiber average fps 281 loudest shot 105.0
Core tip average fps 285 loudest shot 107.0
standar xl average fps 283 loudest shot 105.2
empire average fps 285 loudest shot 106.3
adjusted for velocity core, 281 and 104.8

Results are this, no significant advantages over the carbon fiber. The .2 decibel difference is unnoticeable by the human ear, and the efficiency advantage is so minimal that it would not be worth the time (changing tips), the money ($60 a tip and 2 are needed), or the added weight (compared to carbon fiber).

My opinion is that the carbon fiber barrel is superior.

how ever is you play electric and experience barrel rise, then i would say "technically the core tip freak xl is better".

[Grendel]

I will have to assume you placed the db meter along the path of the shot given the values you provided. Those values are higher then than I would expect [about as loud as leaf blower] so the other assumption is your distance is pretty close to the barrel (co-located with chrono?). If that is the case then you are measuring the expansion of gas (primarily) which would make sense that your measurements are so close to each other. The material of the barrel will have little or no affect on the sound level given they are comparable in porting (or non porting). Keeping the db meter at a fixed distance is good for doing comparisons between things (i.e. barrel comparisons) but I would shy away of having the db meter inline with the shot due to outside of porting it really does not test the differences in barrel material. I would measure at a fixed distance from the barrel at 90 degrees if I was seeing how a particular barrel affects the "loudness" of a shot.

You also do not mention whether you took normalizing background noise measurements. Typically in open air you would do this regularly and use averaging and subtract that from your max measurement per shot to see what the delta is between background and the shot.

[Painthappy]

Sounds like a fun and cool experiment

[Daltech]

What you are doing is awesome.

Some additional metrics will be required to create a usable guide to loudness of barrels as bearded has stated. You’re on the right track and I ever thought to do this despite being a master sound technician. I’ve wondered about the effects of the 100+db pops on my long term hearing, but the barrels so far away from my ears it feels safe. I would like to see db readings from users ear distance, 90• offside and 25 yards down range.

[Daltech]

Please let me know if you have any questions. I’m happy to help.

[Otnasir]

Please let me know if you have any questions. I’m happy to help.

took all your suggestions and re ran experiment with same barrels.

This time we tried it, with the meter in many different locations.

The results were the same, all barrels very close to each other in volume. They all got equally quite as you moved the meter around. But stayed in the same order of loudness.

My favorite barrel is hands down the carbon fiber. The core tipped freak XL was ever so slightly better performance. But in the end the carbon barrel feels the best on the gun and the magional improvement of the core is not worth the hassle of multiple tips or the weight compared to carbon fiber