I do them on a table saw with an index pin jig that is a common way to do it, with a dado blade set.
Background, or why bother.
I play guitar, both kinds of music, country and western.
Old Fender speaker boxes were made of solid pine and box jointed, made them tough enough to hold up for the traveling picker.
My wife got tired of our living room stacked up with beat up speaker boxes, so I went about making some abit more to her liking, and came up with much better sounding boxes.
I ran into many problems,
Since the speaker boxes are about 12" deep, that makes 24 cuts when using 1/4" slots.
The wider the slots, the easier it is for fit, but I like the look of 1/4" slots. That is nearly 100 slots for a speaker box
Error-- acumlative error will kill the deal, get one slot off, the rest will be off, the sides will not fit together. I will get into that.
Clearance-- you have to have clearance between the pin and the mating notch so it will go together, and for glue. I found .002" each side of a pin works for me.
To do that, I add a .004" shim to the dado stack when doing the sides.
On a short box joint that may not be as much of a problem. Long joints with 48 pins and notches, you need the clearance, or it will not go together.
Glue-- on long box joints, even the slower tightbond 3 will seize up before you can get it together, I use slow dry epoxy, not only will it give you the time needed, it acts like a lube, the joints slide right in.
Also, the water based glues will swell the pins.
Blow out-- when you do one side, one end you cut from the front, the other end of the board you cut from the back.
When cutting from the back, you need a back up board, or the wood will chip out the front, leaving a ragged edge around the notch.
I use thin plywood for backup. I found its best to use a backup at all times when working brittle solid woods, helps prevent snapping a pin off.
Back to "ERROR",
The index pin must fit tight in the created notches.
Since I want .004" clearance, I slighlty tapered the index pin looking down from the top,
this way, I can get the narrow notches, and the slightly wider mating notches to wedge on the index pin with no play, otherwise error will creap in, the parts will not go together.
The wood,---solid woods
The work must sit flat against the jig, a cupped, or crowned surface will cause error.
Since wood twist and humps up, the whole procees must be done quickly.
Furthering that problem, the act of cutting the notches, causes the wood to warp even worse, and faster
So, I joint, plane, and cut the notches, then get it together quickly, within hours not days.
I hope some of that may be helpful, but it does take some practice to get the hang of it.
My simple jig hooked to a miter gage, the back part with index pin is adjustable for side to side.
A couple of speaker boxes,
The one on the left, I was still struggling as can be seen blow out, I had to use shims ect. On the right much better dialed in, both amp head and speaker cab.
In an effort to stretch out the limited supply of this 100yr old salvaged spruce, I jointed some pieces for the cab backs using the same jig.