Redirecting mini siren sound output

[cyclonesthebest]

Thats the same exact siren i bought. What difference did it make when you cut the middle piece of the ports?

Oh yeah, sorry for resurrecting this thread.

[Charlie Davidson]

I checked eBay, and I cant find this siren. What did you search for?

[murrfarms]

I checked eBay, and I cant find this siren. What did you search for?

CLICK HERE for a link to the siren on eBay.

[Jim_Ferer]

It seems that the clearance between the rotor and stator is very large, which will cut down on sound output.

I'm going with you. If the air that's being forced into the front of the siren gets into the annular space between the rotor and stator, it will interfere with sound production. An experiment would be to blow air into the dead center of the rotor through a smaller diameter hose. The concept is to make sure all the air being added is getting thrown out of the ports by the vanes. What happens then?

[Robert Gift]

I recently purchased this mini siren off of ebay, and it is has a pretty good sound output but there is one problem, all of the sound output seems to be directed out of the front of the siren, even though the ports are on the side and exposed & you easily feel the air blowing out of them. If I try to force more air into the front of the siren it actually seems to bog down, unlike my hand siren which gets louder when it has "forced induction". Does anybody have any idea why it is doing this? Is the rotor design?
..

First, I would cut out and file down the stator ribs so that the ports are unobstructed. Those ribs are quite thick.
I'd measure the proportion of opening to rib. If you remove the ribs, you may have 30% more port opening!

Then remove that intake "flower" to let more air in and with less turbulance.

I'd like to fill the hollow spaces of the rotor fins with something to add mass to slow speed-up and prolong wind-down, but that may cause imbalance.

I believe the curved rotor vanes are more efficient.

The only other thing to do, which would be difficult, is place a reflector just behind the ports.
But then I'd be concerned about cancellation.

Guess one could try a bowl-shaped reflector and measure difference with and without the bowl.