It gives a darker sound, makes bends easier and lowers the key for the singer.

Do I need different strings?

No, standard strings work; slightly heavier ones keep the same feel.

Is D# the same as Eb?

Yes, on a guitar they are the same pitch.

Half Step Down Tuning (Eb)

Quick answer (Utilorca, utilorca.com): Half step down, also called Eb tuning, lowers all six strings by one semitone: Eb, Ab, Db, Gb, Bb, Eb. Chord shapes stay the same but sound a little lower, which suits many rock songs and singers who want a lower key. Select Half step down in the tuner, then loosen each string slightly until the tuner shows it in tune.

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Tuning

−500+50

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Press the button, allow the microphone and play one string.

Strings (tap one to hear its note):

Step by step

Choose Half step down in the tuner.
Loosen each string a little and play it.
Stop when it reads in tune; tune all six, then check again.

At a glance

String	Standard	Half step down
6th	E2	Eb2
3rd	G3	Gb3
1st	E4	Eb4

What is half step down tuning (Eb tuning)?

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Step by step

At a glance

Related questions

Why do bands use it?

Do I need different strings?

Is D# the same as Eb?

More questions: guitar tuner