Club Obi Wan

The thread on whip crack physics gave the inspiration to do something I've been planning to do anyway, that is to check sound decibels of whip cracks. I did three basic cracks, 3 facing a fence and house, and the other three facing an empty field. I set the sound meter to record the max decibels for a 30 second period. I then did as many cracks as I could within that 30 second period, but without rushing it. I did three sets of these for each crack and recorded the loudest one. The sound meter was sitting on top of an upturned bucket approximately 5 ft from the whip cracks. Here are the results:

House and Fence

Circus crack 103 107 106 avg 105
Overhead 102 97 100 avg 99.7
Forward throw 107 104 106 avg 105.7

Field

Circus crack 110 110 109 avg 109.7
Overhead 99 106 93 avg 99.3
Forward throw 105 100 95 avg 100

One thing I found interesting was that I had always thought that my overhead crack was my loudest crack, but as you can see, it's not. I think it may just seems louder because the crack takes place a little above you, so you are always within the sound waves, whether your cracking into an object or the open land. There was a noticeable drop in "loudness" between the fence and open field, but the noise level is the same. The test was done using an 8ft nylon whip I made. I wouldn't do this with one of my roo whips.
Jim

Very interesting... I thought the same as you, the overhead was significantly more louder than my other cracks. You can't argue with your sound meter results.

Cracker wrote:I wouldn't do this with one of my roo whips.
Jim

Um... why not?

I've read that you shouldn't try to crack a leather whip as loud as you can because it will put undo stress on it. I've got nylon whips that I don't mind abusing, so that's why I used one of them. It probably wouldn't hurt the roo whips, but I don't want to take a chance.

To be scientific about which was (generally) louder you should have averaged all cracks of a certain type and recorded that number. Not the loudest one.
Interesting none the less.

The higher pitched that a sound is, the more directional it is. I don't begin to know how you would tell which direction that a sound would travel from a popper, but I think that the crack of a whip is a fairly high pitched sound.

I do know that when I am cracking whips with someone, and they are doing a circus crack, it is much louder standing in front of them than it is standing behind them. This would also indicate that due to the pitch of the crack, that it is a quite directional sound. I am only guessing that the sound of an overhead may actually be louder off to one side.

At about 80 hertz and below, the human ear is incapable of determining which direction a sound is coming from. This is why the location of the subwoofer in a sound system whose high cutoff is 80 hertz or lower, is less critical than the tweeter in a speaker. The subwoofer can actually be located in the front or rear of the room, and the human ear can not tell the difference.

Having said that, the direction of the sound would have a lot to do with it's sound pressure level. I also think that the overhead is quite often louder than the circus crack. I think the directionality of the sound probably has skewed your test results.