It's just ok. One spot of clipping but info from @xanmato above is going to get applied when I get home tonight.
An update to my experimenting.
My Ecolink siren arrived this afternoon. I tested the default sounds and was not particulary excited about them. Some were rather soft, even at 100% volume.
I took the 45 custom sounds that I had created for my Aeotec Gen 5 doorbell/siren and downloaded them to an empty micro SD card. Although the Ecolink instructions said to format the card for FAT16, I think mine was formatted to FAT32 as it was a 16 gb card I had in the drawer. I did not bother reformatting. The siren read the file just fine.
The volume of the Ecolink siren is similar to that of the Aeotec. I set the volume for each announcement when I created the sound files.
I am delighted that Ecolink came out with a device that mirrors the functionality of the Aeotec Gen 5 devices which are no longer available from Aeotec. If anyone purchases one of these devices and needs help with custom messaging files, I will be glad to assist.