LDC comparison
I like numbers, graphs and charts. After I got my shroud end-cap to UNF adapter, I had to run some tests on the effectiveness of various LDCs. I got a 2″Dx4″L from Donny and a 2″Dx7″L from Neil (Clague). I recorded the actual waves and use Audacity to plot frequency-power charts. The charts were actually somewhat difficult to read for comparison purposes. So I compiled the numbers in a spreadsheet to show the relative reduction (against stock but with an UNF adapter instead of the usual end cap). Attached is the result.
Note that past 18kHz, the level of the stock is very low, so the apparent lack of reduction past 18kHz has no impact on what we actually hear. According to Wikipedia, human ears are most sensitive between 2kHz to 5kHz, that is the region where we should focus. The higher frequencies can still alter the texture of the sound.
Oh, I forgot to mention the stock shroud already has 4 1.5mm venting holes drilled at the base. I did not do any tests of what it is like without the venting holes.
Also, the POI did not change visibly at 10 yards without, or with either LDC.
To my ears, both LDCs are effective, with the 7″L unit edging out a little bit. But that is to be expected due to the increase of volume. The real question to ask is how many dB is worth how many inches. The 4″L LDC makes the Shorty 27″ long, the 7″L LDC makes it 30″ long.
And then yet another question to ask (for prospect buyers) is whether it is better to get a Mutant Standard with a longer barrel and longer stock shroud to begin with, or get a Shorty then add an additional LDC.
I am just providing the data, you make your own conclusion!
All Replies
Viewing 7 replies - 1 through 7 (of 7 total)
:dito:
I have been waiting for a post like this for years. I have been so frustrated by the lack of quantitative data on the effectiveness of LDCs. My own limited experience has been very frustrating and disappointing. I wish I could contribute but I do not know anything on this topic worth sharing. However, I a willing to learn. Thanks to all of those who are contributing on this topic. It is much appreciated.
Scott, I am planning to shoot the Mutant Shorty on Sunday! Will bring that (for sure) with Donny’s Fat Boy on it. Thanks in advance!
Tak,
Talk with me Sunday ( If your shooting ?) & will share a few LDC tricks that you could apply w/o adding a supplemental LDC to the end of your factory shroud :biggrinn:
Donny, your LDC does very well given its length! And yes, I like the fact that it can be opened up for upgrades and repair. For a short bullpup, I am using your Fat Boy instead of the 7″ LDC because the whole idea is to keep it short, right?
Furthermore, the internals of your LDC do not survive any powder burner discharge, which is good to know for obvious reasons :whistle: .
Also, beyond a certain point, any reduction of muzzle report is somewhat pointless because impact on target is much louder.
I just find recording the waveform and using a program (Audacity, open source) to analyze it to be very rewarding in its own way. I know some people go strictly by their ears, but I like to see numbers and graphs, and run formulae in a spreadsheet.
One thing is for sure, just volume and baffles is not as effective as sound deadening material. The stock shroud is just baffles (complex ones!) and volume, I am sure it can be made more effective with different internals.
Hey, here is an idea! Find out the best internal design to retrofit a factory shroud for more effectivness! The Mutant shrouds (Shorty and Standard) are fairly easy to disassemble, so this is probably feasible though may not be profitable.
Very cool info! Other than the difference in length, mine also allows you to unscrew the end caps for those who like to tinker or once in awhile check for clippings/maintenance. Then there are guys who want nothing to do with the internals and shoot as is so. That’s something else to consider as well.
Viewing 7 replies - 1 through 7 (of 7 total)
- You must be logged in to reply to this topic.
We in the state of California where the firearm Silen**** is illegal and having them on air weapons is accepted tho still sorta grey :whistle: …. disclosure & showing or talking about them comes at risk of persecution, we can’t / don’t disclose much.
Will say this … those LDC’s which utilize multi chambers & partition baffles to attenuate sound waves do better than packed pass threw core types.
More volume absorbs pulse energy better than less does … :whistle: