Realistic sound reduction expectations with Sorbo Pad

[ao_tenshi]

Hey all,

This is not an issue, but more of a question to the community of experienced airsoft players.

I recently, for the first time, installed a sorbo pad (Scatterplot SorboPads - 3/16") into my KWA M4. What I've done is sandwiched the sorbo pad between the cylinder head and the original rubber pad. Also adjusted AOE on the piston.

Had some gearbox seizure issues earlier, but that was resolved using a shorter length spring.

Now, I heard a lot about sorbo pads reducing the sound of the gearbox, which was my original motivation (along with stress on gearbox) for the install. However, to my disappointment, I did not notice ANY difference in loudness from the piston impact sound. Did I do something wrong or had wrong expectations? (Specifically, the loudness of the piston hitting the cylinder head sound is clearly unchanged) :banghead:

Any suggestion on reducing the sound in this gun would be appreciated.

[slntdth93]

I think some of the sound reduction from sorbo's is the reduced contact/impact area of the cylinder head, and the piston

If I recall, the "silent" sorbo's were a thin ring that would go on top of the other cylinder head material

[ao_tenshi]

Originally Posted by slntdth93

I think some of the sound reduction from sorbo's is the reduced contact/impact area of the cylinder head, and the piston

If I recall, the "silent" sorbo's were a thin ring that would go on top of the other cylinder head material

That make sense, Im using the full size sorbo... should I reverse the order in which i currently have the sorbo installed?

Current: piston head -> sorbo -> rubber pad
New: piston head -> rubber pad -> sorbo

[EOD Steve]

Are you referring to the stock rubber pad or the neoprene pad that normally ships with a Sorbo Buddy pack?

If you're retaining the stock rubber pad, then you only need to use a 1/8" sorbo. In your nomenclature, it would be piston head, sorbo, stock pad
If you're ditching the stock rubber pad and using the neoprene pad, then it would be piston head, neoprene pad, sorbo pad.

[ao_tenshi]

My sorbo did not come with neoprene padding... just the sorbo pad itself. I'm using the rubber pad that was originally in there.

Originally Posted by EOD Steve

Are you referring to the stock rubber pad or the neoprene pad that normally ships with a Sorbo Buddy pack?

If you're retaining the stock rubber pad, then you only need to use a 1/8" sorbo. In your nomenclature, it would be piston head, sorbo, stock pad
If you're ditching the stock rubber pad and using the neoprene pad, then it would be piston head, neoprene pad, sorbo pad.

[EOD Steve]

You'll probably not want to use the 3/16"pad then unless you plan on shaving a lot off your 2nd/3rd tooth off your piston.
I recommend the 1/8"pad.

[lurkingknight]

It doesn't really quiet it down it changes the sharpness of the impact sound depending on what materials the piston head and cylinder head are. Sorbo's primary function is aoe correction, the shock absorbing nature of the sorbo absorbs impact forces at the front of the gearbox, helping prevent shell failures at the corners of the cylinder window. Anything else that happens as a benefit is a bonus, not a goal, imo. If you had a plastic CH and PH to start with, chances are the hit wasn't very loud to begin with. Also the lighter the piston assembly the lighter the sound.

[ao_tenshi]

Thanks for the suggestions! I guess I should of got the thinner 1/8" sorbo instead.

Just out of curiosity, has anyone used the ring-like "silent" sorbo pads before? If so, how well do they perform in terms of loudness?

[lurkingknight]

they are for silent piston head/cylinder head combos from systema. They are not for your application.

[ThunderCactus]

It makes a more noticable difference when youre the one being shot at. Then problem is you're still directing the noise at your target. Having a suppressor will lessen the barrel rapport, but the receiver will still be noisy.
thats okay though since from 30ft away youre not likely to hear the mechbox noise of a single shot from a suppressed gun.

[Cliffradical]

I have a Mask V2 set dropped into a nicely shimmed gearbox, feeding an MP5 SD6. The thing is quiet as hell (relative to a regular AEG).
AOE and a decent spring guide really help to clean up the noise a gearbox makes, just by keeping the piston as straight-in-line as possible. A suppressor changes the noise made by the piston head from a "clack" to a "thump", and then the gun will sound differently when loaded vs. dry firing.

It's all about trying to mitigate "errps" and "thwaps", as opposed to overall sound reduction, because lower frequency sounds are harder for the brain to pinpoint.

Edit: We're talking about fractions of a second of reaction time difference here so, YMMV.

[Hectic]

8Well its all prety much been said, sorbo mostly changes the tone or muffles/dampens the impact so the sound isnt as sharp and doesnt carry as much. You can build a prety quiet aeg, especially at indoor velocities but its a combo of piston head, cyl. head, sorbo thickness and stiffness, spring strength, piston weight, shimming, gear quality, motorand motor height, even plastic vs metal body, full stock etc..
I have this cyma mp5sd6 i built, its prety quiet for sure.
3/16 soft sorbo directly on the stock rubber, pom piston head, swisscheased lonex red piston, stock motor, 13:1 shs gears, bearing bushings, shimmed nicely verry little slop, m90 spring
edit: i should add its also quiet because its pushing 30rps so response time is fast so the cycle doesnt last long enough to create alot of sound. Tho it is still not loud on full auto

[ao_tenshi]

Thanks for all the suggests everyone!

So to summarize below are some of the key components needed to achieve a quiet effect, along with what I currently have installed.

1) Silencer - 5.5" aluminum silencer installed
2) Cylinder Head - stock KWA
3) Piston Head - Modify Polycarbonate
4) Piston - stock KWA (AOE applied)
5) Sorbo Pad - Scatterplot Sorbo Pad v2 D70 3/16"
6) Gears - stock KWA
7) Motor - stock KWA

Will also look at swiss-cheese the piston, but not looking at swapping gears or motor at the moment.
Any suggestion on a good Cylinder Head? (hopefully KWA cylinder head is not proprietary).

[ThunderCactus]

Any metal one that seals well, really. The sorbo pad is doing all the work for you.

As far as gear/motor combos, instead of trying to go quiet, just go fast.
It's going to be way easier to make the rapport as short as possible, instead of as quiet as possible. That being said, both can be done to some extent, just shim them really well and use bearings.
Helical gears will reduce the noise of the gears, but only if your mechbox is in perfect spec with the size of the helical gears. If the holes are just slightly too far apart, you'll get slack between gears just like you would with flat toothed gears.

And the last thing is matching cylinder to barrel volume to it's most silent point.
I have no freaking clue what that point is, but it requires undervoluming the gun silghtly. You want the piston to still be compressing air when it hits the cylinder head for a lower velocity impact.
I can tell you my VSR-10 was super deathly silent without even having an air brake; because the piston wasn't free floating at full speed into the cylinder head. 440fps spring still gave me 420fps, and the suppressor helped a bit (I was only using the last 1.5" of it though). Mind you the cylinder in that gun is probably meant for like a 550 barrel and I was running a 430 lol

[Hectic]

Quite true TC I didnt mention that, if the bb has left the barrel before the piston travels fully the impact will be much louder.
the vsr cyl. Is matched to 500mm. Increasing bb weight reduces velocity and thus takes longer to exit combating over volume. I run 455mm on full cylinders and use .30 bb's that seemes to be a prety good match.