I would really like to know how to make the Samsung GT-S5233 or S5230 (Star) speakers louder because they aren't really that loud. Any help please?

Dont know if this works on the STAR, but you could give it a try:

Go to dial screen and enter this code:

a new menu is loading.
Press # until you find "[3] SPK Config", press "3".
Now, I guess you want your MP3s louder: Find "[4] AV-QTune(MP3)", press "4".
Find "[1] SPK MP3 Vol", press "1".
Now there should be a table with dB-values like this:


If you press the number of a line (e.g. "0"), the top lines last word should change to "WRITE".
Now you can tap the blue edit box below and enter a new value. (e.g. "-80" to set it to "-8.0dB").

But be very careful with these settings!!
If you overdo it, your speakers could blow!
Changing +6dB means double loudness!

Thanks for the help but unfortunately the code does not work. I found something similar though.
*First I type this code:

*Then in Internals (4) the code is:

*Then I click Test Mode (3)
*Then I click on Audio (5)
*Then SPK Config (3)
*Then there is This: SPK Load, SPK Dump, SPK VOl Total, SPK Wave/MP3, SPK ETC

From there I don't know what to do
Can Anyone please help me from there???

I would try "SPK Vol Total" for calls and "SPK Wave/MP3" for music.
Just my opinion.