The sound on the SHL9705A's definitely exceeded my expectations. With no equalization (flat) or other audio "enhancements" enabled on my One X, they were a bit quiet. Of course, this is going to happen on almost any on-ear headphones when used with a smartphone - the headphone amp just isn't powerful enough unless you really open up the volume taps. With the Philips app installed, you're prompted to select a headphone product to "optimize" your audio for a particular headset. Choosing the 9705A cranks up mids and highs to be more in line with the bass, resulting in a more balanced listening experience at moderate volumes. If you max the volume, you and your eardrums are probably better off with these enhancements turned off. In terms of character, the big 40mm drivers in the 9705A's provide the typical warmth on the low end of the spectrum that even high-end earbuds will struggle to emulate. Bass isn't particularly strong, but always perceptible - which is to say right where I like it. You hear and feel low frequencies, but they never overpower a track. Fidelity is very good, I'd put these on par with entry-level on-ear products from Sennheiser like the PX100II's, which are cheaper. The 9705A's do get a little harsh at high volumes, and that's when you'll want to turn off Philips' enhancements. And for $100, you can get better accuracy and bass performance from other headphones. But the Philips don't stop at good sound.