How MP3 Affects Sound Quality – A Visual Analysis

While studying high quality audio compression techniques, I often found myself asking this question: How much does MP3 affect the sound quality?

MP3 is a perceptual codec based on psychoacoustic models. It reduces precision in areas beyond average human auditory resolution.

If your ears are trained to listen for small details, such as ears of a musician or sound designer, or an audiophile HiFi nerd, you’re more likely to notice artifacts. Especially when you’re listening over brilliantly sharp speakers or headphones.

Obviously one way you can tell how much MP3 affects the sound quality is by simply converting your high quality uncompressed LPCM / WAV file to MP3 with various different bit rates and then listen and compare. But the differences you notice are hard to communicate.

Another way you can judge the impact on sound quality is to do a visual frequency spectrum analysis for various different bit rates, and then just look at them.

That’s exactly what I did with the uncompressed 182 MB original of my Sea Waves & Rain file from SoundCloud.

The frequency spectrum of the uncompressed, slightly edited LPCM file looks like this:

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Buttons vs. Touch Sensor Points

If you’re into tactile and skeuomorphic design, you’ll want to know about an alternative to the standard target-action pattern of UIControl. A pattern that can make your UI feel more realistic but also respond to touch events more intelligently than relying on “atomic” hot zones.

Imagine a really awesome, fun to use calculator with a grid of UIButton objects. Each of them triggers a specific action.

The way how UIButton in particular or UIControl in general works is that when the finger initially goes down on the button and touches up inside the button, a “touched up inside” control event is triggered. When the finger touches up outside, the button is cancelled.

Some developers make use of the various control events to make the UI more skeuomorphic, more realistic, more fun. Usually this goes beyond just triggering actions upon touch up inside, such as tweaking the appearance when the button is pressed, about to be cancelled (finger outside the hot zone but still on screen), and so on.

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