non-latching sound activated switch

Hi,

I have been looking for a noise activated siren that would sound when noise is detected and then stop sounding when the noise level decreases. I haven't found anything ready made that meets these specifications. Most of the boards I have looked at are latching (e.g. the clapper). One board was non latching but if I had conected it to a siren, my understanding is that the siren would remain on whether the noise disipated or not. What I would like is the circuit to depend on the decibel level of the sound. Is this possible?

much obliged,
Corine

Don't you think the noise detector will hear the siren and keep the siren going?