Recently purchased an Airchime K5HA and it doesn’t sound quite right.I am running 1/2" airline to them with about 135-140 psi.They are very loud but have a tinny non melodious sound.It has all the same bells of a K5LA but with a high manifold.Was hoping for them to sound like the K5LA.I did notice that there are no gaskets between the bells and the manifold.
Can you drop a recording on uTube for us?
-Kris
I can but might be a couple days…The weather is not being real cooperative this week…
Tried a clip from my phone but must be the wrong format and/or size…It just sound like all the bells are sounding the same note…
You mentioned you have no gaskets… Have you had the bells off to verify that there are no o-rings? You won’t necessarily see any gaskets when assembled.
If there is nothing making a seal, and air is leaking, it could cause a different sound. Maybe try upping the pressure to test this. Mine sounded like a wounded goose when they weren’t getting enough air.
When I received them via ups, the long bell was detached to fit in the box…Don’t recall seeing an oring…definitely no gasket…I will have to pull all the bells to double check…might do that tomorrow…my max pressure is about 145, that when my pop off valve goes…If I take a bell off and there is no Oring or gasket, I will definitely remedy that.Just trying to get some idea why the tone sounds flat…
Made some gaskets for the bells even though they have Orings on them…Noticed a slight difference.Starting to think maybe the diaphragms are just stiff.The more I blow them, the better they sound.
Half inch air line … is this half inch outside diameter, or half inch inside?
This would cause a huge difference in sound quality and projection.
-Kris
Actually the hose says 5/8" on the outside so that would probably make it a 1/2" ID…They are starting to sound better though…I gave em a good workout yesterday for a noon whistle at an antique power show.They were quite loud.May have to invest in a pair of ear plugs 
Sounds okay, a bit quiet though.
Let’s do this … on the bells themselves, what are the numbers? It should be a 1L, 1, 2, 3, 4 … or 1, 2, 3, 4, 5 …
Should look like this on the bell (this is a #2 bell):
-Kris
Like I said…Her tablet microphone doesnt pick up very well.Believe me, they are loud in person.There is a 1, 1L, 2, 3, 4. On the bells.
Okay so a couple more things …
Your valve … what are you using?
Air line … what’s the distance from the tank to the valve, and then the valve to the manifold?
Crack open the backs of the bells and attach some pics. Just need to confirm the internals are good.
-Kris
Using a 1/2" ball valve…from tank to valve maybe 3 feet, about the same from valve to manifold…tried to keep it as short as possible…As far as I can tell the diaphragms are new.
Ball valve might be the problem, as it’s not letting enough volume through.
Can you switch to a Graham White, or another type of valve?
This is what mine sound like and I’m using the knock off of the GW valve: https://www.youtube.com/watch?v=VyxbgQSio4Y&t
-Kris
I have a GW valve but it would take a lot of work to put it in…The vid you posted pretty much sounds like mine do in person.If the weather ever straightens up, ill try to get a good recording of mine.
I installed the GW valve and I think it sounds worse…Plus have to really pull on the handle to get wide open…I oiled the valve and made sure it was completely free…I think ill go back to the ball type valve possibly a larger one to see if that is the issue…
Remove bells from manifold. Remove back caps. Are the diaphragms stuck to the back caps? Yes? Take a paperclip and push them out of the back caps. Then, flip the diaphragms over or replace if necessary. Re assemble the horn. Test with compressed air. Is louder? Yes? You fixed your problem. 
I just ran into this with a Nathan K series #3 bell. The diaphragms should be able to move or vibrate freely while in the back cap. They Jam up for some reason sometimes.
That’s a possibility but pretty sure the diaphragms are new since I bought them refurbished from Air horns of Texas.Couldn’t hurt to check I guess.Thanks!