The horn you show and talk about in this post is not too bad! I've been using this horn for the past lot of years (guessing 10 years??). I am a speaker junkie I quess. I would buy other speakers and always came back to this horn.
What I didn't like about it was the 8 AA batteries and their short life. This horn always had a loud click when energized. This horn also sounds kinda tinny, but no worse than most of the 5" speakers. All the controls for the other sounds got in my way, I ran a strip of cammo duct tape over the controls to hide them. There is a sling mount on that horn, I ran a piece of para cord thru them so I could hang it from a branch.
Since I found the Speco amplified speaker this horn is now in my spare part drawer. Going to keep it just-in-case! I'll tell you honestly, I had your exact set-up and switched to the amplified speaker, there is a WORLD of difference. HUGH difference. If you can afford to try the Speco speaker, try it, i'm sure you will be amazed and happy!! That's a great set-up you have!
I see that Rio MP3 player! Nice, I had that same model (s35s), worked great and the controls are easy to use. Recently I swithed to an iRiver w/256k, I like the controls better on the Rio. No real reason for switching, just because I wanted a new toy and more memory (too expensive to upgrade the Rio). Gave the Rio away as a present. Kinda wish I kept it. Only thing I didn't like about it was the software. The iRiver software is more refined, but the controls are much more akward.
Trade-offs, everything is a trade-off.