So I finally got to get my hands on an LXT myself and did some side by side testing. I want to thank Kyle Grob of KGmade for sending me his LXT to use. Kyle and I have spoken on the phone a few times but we have never met. When I asked him if he would send me his LXT he didn’t even hesitate in saying “sure no problem”. He said he has done it many times and the 2209 has always given him lower numbers than the LXT but they were close.
To get things started I simply took the LXT out of the box turned it on and set it up next to the 2209. The first couple tests were what I have experienced in the past, the LXT gave some pretty random very low numbers. I called Kyle and told him what was going on. Kyle got me on the phone with one of his guys Chad that runs the LXT the most. Chad got me into a new screen to use that held the Peak Impulse number. When in this screen you have to press 4 buttons between each shot you take to reset the LXT. When in this screen the numbers were a bit closer to reality. In my testing the LXT always gave low numbers ranging from .1 dB to 3 dB. Much better than what I have seen in the past but nothing that I would be willing to use for stack development. I did a 10 shot MilSpec test that Kurtis (our lead engineer) did some statistical comparison of. Here is the email Kurtis sent back to me
Here is a single string from the 2209 and LXT sampling the same shots from 20" .308. Mil-spec test with the two meters lined up parallel with the gun barrel so they were both presented the same event without one influencing the other (they were front to back). At first glance the LXT is only off by about 1 dB but when you look at each individual data point you can see that the LXT variation is not consistent. This inconsistency is caused from both the low sample rate and high rise time.
I also performed a statistical comparison of the 2 data sets. The dependent means T-test compares multiple data points of the same event and shows if the data collected are statistically the same. This test uses the mean from the 2209 (136.375) and compares deviation of each event (gun shot) to the mean of the true data set (2209). A p value of 1 would mean the data points are exactly the same and a p value of 0 means the data points are not the same. In this case the p value is 0.001671 which means we can say with 99.8% certainty that the data collect by the 2209 and LXT are not the same. The LXT is not a mil-spec meter and data from it cannot be trusted as "true" to the event.
Here is the data string
After a few days on the range doing some side by sides after learning the better way to run the LXT I can see how some of you say they are always pretty close and you don’t understand the crazy results I and others from the industry have seen with the LXT. I will admit it is better than what I have seen in the past but not something I could use to develop baffle technology. Anyone using an LXT and not doing the 4 button dance between shots can totally discard the numbers. I don’t know why the numbers are so different between screens but they are. Peak Impulse should be Peak Impulse.
For Kyle to say 2209 is always quieter than LXT for him and me seeing the reverse along with the comparison from Kurtis as well as a few days on the range doing side by sides I could not trust numbers from an LXT.
After having some hands on I can see how the LXT is very easy to use completely wrong. It makes the numbers from the Guns & Ammo 338 article and other times I’ve tested side by side make more sense to me. Even when used correctly it is insufficient for my needs as a manufacturer and should never be used to give industry numbers.
To get things started I simply took the LXT out of the box turned it on and set it up next to the 2209. The first couple tests were what I have experienced in the past, the LXT gave some pretty random very low numbers. I called Kyle and told him what was going on. Kyle got me on the phone with one of his guys Chad that runs the LXT the most. Chad got me into a new screen to use that held the Peak Impulse number. When in this screen you have to press 4 buttons between each shot you take to reset the LXT. When in this screen the numbers were a bit closer to reality. In my testing the LXT always gave low numbers ranging from .1 dB to 3 dB. Much better than what I have seen in the past but nothing that I would be willing to use for stack development. I did a 10 shot MilSpec test that Kurtis (our lead engineer) did some statistical comparison of. Here is the email Kurtis sent back to me
Here is a single string from the 2209 and LXT sampling the same shots from 20" .308. Mil-spec test with the two meters lined up parallel with the gun barrel so they were both presented the same event without one influencing the other (they were front to back). At first glance the LXT is only off by about 1 dB but when you look at each individual data point you can see that the LXT variation is not consistent. This inconsistency is caused from both the low sample rate and high rise time.
I also performed a statistical comparison of the 2 data sets. The dependent means T-test compares multiple data points of the same event and shows if the data collected are statistically the same. This test uses the mean from the 2209 (136.375) and compares deviation of each event (gun shot) to the mean of the true data set (2209). A p value of 1 would mean the data points are exactly the same and a p value of 0 means the data points are not the same. In this case the p value is 0.001671 which means we can say with 99.8% certainty that the data collect by the 2209 and LXT are not the same. The LXT is not a mil-spec meter and data from it cannot be trusted as "true" to the event.
Here is the data string
After a few days on the range doing some side by sides after learning the better way to run the LXT I can see how some of you say they are always pretty close and you don’t understand the crazy results I and others from the industry have seen with the LXT. I will admit it is better than what I have seen in the past but not something I could use to develop baffle technology. Anyone using an LXT and not doing the 4 button dance between shots can totally discard the numbers. I don’t know why the numbers are so different between screens but they are. Peak Impulse should be Peak Impulse.
For Kyle to say 2209 is always quieter than LXT for him and me seeing the reverse along with the comparison from Kurtis as well as a few days on the range doing side by sides I could not trust numbers from an LXT.
After having some hands on I can see how the LXT is very easy to use completely wrong. It makes the numbers from the Guns & Ammo 338 article and other times I’ve tested side by side make more sense to me. Even when used correctly it is insufficient for my needs as a manufacturer and should never be used to give industry numbers.
