The quality of sound reproduction of a helmet is mainly expressed by the numerical values ​​characterizing bandwidth.

To choose my audio equipment I always base, first, on the bandwidth, that each device must be able to pass or return a bandwidth of 20 to 20,000 hertz, which is what can best hear a very good ear.

After testing the Philips headphones "Downtown" whose bandwidth extends from 18 to 22,000 hertz I did not think that the helmet Philips 'Uptown', whose bandwidth is wider (12 to 23,500 hertz) could restore a better sound because its superiority is in inaudible frequencies (no ear is able to hear the bass below 20 Hz and higher highs at 20,000 hertz).

But after testing the Uptown headphones I see that I was wrong; Indeed, when I listen to orchestral music, for example a symphony or concerto, the difference is significant: quality is significantly better with the Uptown Downtown helmet with the helmet, it seems to me better defined. The reason is probably that in the Uptown headphones frequencies near 20 Hz (the most serious), and close to 20,000 hertz (most acute) are less attenuated than in the Downtown helmet.

Furthermore the flat cable range citiscape is handy. The volume control is useful but, for me, of limited interest.

Finally, I said that I use this headset with a Nokia Lumia 800 and I found that Nokia offers for this smartphone, a helmet with a smaller bandwidth but at a price 2 times higher!