The iPhone 5S looks identical to the iPhone 5. It only has a beefier 64bit processor and M7 co-processor, Touch ID and an improved camera to start off with. But it also has something else that wipes the floor with the 5 and older 4S/4 iPhones.
The iPhone 5S has a new audio codec and class D amplifier by Cirrus Logic. This incorporates the digital to audio conversion of the MP3 tracks and then powering your headphones or the inbuilt speaker.
The difference in sound quality is night and day with superb range, dynamics, punch, separation and clarify.
Gavin's Gadgets & Photography 
So it is the case that the older phones weren’t that good at music playback; which explains why the htc one is better.
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The 4S was very good but the 5 was poorer. The new iPhones have addressed this.
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So which would you say had better sound: 5S or Htc One?
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Tough one Graham. Loudspeakers are better on the One as stereo and have more depth. Via headphones fairly close. They have different sound signatures. Dependent on genre could go either way.
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My son’s just bought a 5S. He’s a professional musician. I’ll see if he can do a comparison for me. It may have to be a blind test as he’s a bit of an Apple fan and might be biased!
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Lol overall I would give it to the HTC One but the 5S is a cleaner reproduction.
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The iphone 5s as loud as the HTC one or louder than 4s via hp?
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Via headphones. First place HTC One. 4S. Then 5S.
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Yeap, was expecting that on what i found out at head-fi.org.
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But a lot does depend on specs of headphones too.
Also genre of music. I think jazz and classical sound best of the 5S for example.
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