Is it SoundHound that you are referring to? That's an app kind of like Shazam. I'm not sure what you,re trying to do so I'm not sure if that was helpful. I tried to look up sound horn but didn't see it in the app store.
Yes, it's Sound Hound and it worked like I wanted it too. Pretty much.
I used Zumo Cast to play songs from my iTunes on my iMac. I don't use the iPod in the iPad. Then when the song started playing (Simon & Garfunkle's Bridge over Troubled Water) I brought up Sound Horn. It listened to what I was playing and immediately came up with either lyrics or even a video. The video was the Free Concert in 1981 that I was at in Grand Central Park.
However the next song it didn't do very well on. Cecilia it listened to but came up empty. I paused the song, pressed the microphone and spoke the songs title and it brought up suggestions and I picked Cecilia and we were in business.
It also worked quite well with Pandora. Perfect? No but darn worth the $5.00 I spent on it.
Anyway I know this has been a conversation with myself, thank you teachers's pet for joining in and maybe this will help someone else out there. Thanks for those who stopped by to look.