How do I add new music?

Download AddmusicK and follow this tutorial to insert custom music.

How can I change the title screen music?

Go to \asm\SNES\tweaks.asm in AddMusicK and change line 39 (!Title = #$XX) to your desired inserted song number.

How can I change the music played in the intro level?

Go to \asm\SNES\tweaks.asm in AddMusicK and change line 37 (!Welcome = #$XX) to your desired inserted song number.

How do I create custom music?

Information on the syntax and commands used for creating custom music can be found here. AddmusicK's readme also has a handy syntax and command reference.

My song uses the wrong samples - how do I fix this?

There could be many possible reasons for this.

First, check the .txt and see if there is a #samples definition present. If so, within that, look for the presence of either #default, #optimized, or a long list of sample names that end with the form XX SMW @YY.brr. If none of these are present, sound effects and/or songs using vanilla samples may start to sound off due to their required samples not being loaded. Check out this thread for more information on what songs and sound effects use which SMW samples.

Second, if your song uses custom samples, make sure they are loaded in the song. Once again, check the #samples definition to see if all the required samples are called within there, and then once again within the #instruments definition. Look for a #path defintion as well; keep in mind that this changes the default folder AMK looks for samples in (e.g. #path "mario" will make AMK look for samples within a folder called mario inside AMK's samples folder).

For global songs specifically (e.g. star, P-switch, etc.), samples @14, @17, and @21 are not loaded by default if the local song (i.e. level music) does not use them. This can be easily fixed by opening Addmusic_sample_groups.txt, and under all the listed sample groups (e.g. #default, #optimized, and any custom ones) adding an exclamation point (!) after the desired samples. This comment, while a specific instance, explains this more in-depth.

For more information on the syntax required to call samples, check the AddmusicK readme.

My song still isn't inserting. Did not specify target program?

Most of the time, if you're switching from an older AddMusic to AddmusicK, you're going to need to go into your .txt files and add #am4 or #amm, depending on which one you're switching from.

Why does my song glitch really badly on snes9x/bsnes/etc.?

If the song you're using is very dated, then the glitches may be caused by incompatibilities or now-invalid commands that were once acceptable in the older but glitchier versions of AddMusic. One potential issue may be an echo delay that's too high, causing the echo buffer to overflow into instrument data. Find $F1 $XX $YY $ZZ, and try reducing $XX. Bear in mind your song might sound different.

Newer versions of Snes9x have a fix for this. Go to Emulation > Hacks... and check the Separate Echo Buffer from RAM box. Note that this is meant for compatibility with older ROM hacks, and should not be relied on for anything being made in the present.

Why does my song glitch really badly on ZSNES?

If all sound is cutting out due to certain sound effects (usually fire ones), a possible cause for this may be ZSNES's incorrect handling of noise instruments. Switch to a different emulator.

AddmusicK is giving me an error stating that ARAM exceeds - how do I fix this?

In the song file, find a command that reads $F1 $XX, the $XX being any two digit number. Lower this number until AddmusicK will insert the song. Bear in mind your song might sound different.