Do they have different sounds or something else??

Thanks
Dave

No, the timbre is the same. The Eb is a smaller horn, sounding a 3rd below the big Bb horn. This means to achieve a the same C (your tuning note) on the Eb all you have to do is play a G. This advantage makes it easier to play the high notes, but a lot of people will play the Eb horn as a cop-out because they can`t play the high notes. There are 3 solo concerti originally written for the Eb horn, the Haydn, the Hummel and the Neruda concertos. I wouldn`t worry about playing the Eb until you have a really, really good understanding of the Bb. The Eb presents its own problems. The smaller the bore, the worse the intonation will be. But like I said, come close the mastering the Bb before you worry about the Eb.