I'm sure over the years, you have all stumbled upon this type of article. I'll lay it out for you what is involved in it to save you the trouble of reading all that.
The article I've linked to and countless others have one thing wrong. They say to tighten the screws holding the speaker on all the way. **WRONG** If you do that, you will bend the speaker fram and then it won't be able to vibrate correctly. In really bad cases the speaker might even rub on the frame and that would wreck them pretty fast I imagine.
Step 2 is pretty controversial - some people swear by hosing out the inside [literally!]. Those people are crazy in my opinion. I'll be blasting with compressed air, vacuuming it out, and then wiping it down with mineral spirits to get the last of the little particles.
Regarding step 7, my 1960a slant cab from 2002 has a center post screw - the 25/51 straight cab from 1987 does not.I dunno when they started doing the screw, or the post - both of mine have the post though.
I will NOT be rewiring the thing, or getting rid of the quick disconnects. It works, and it's a time-tested approach. Sure, solder is a much better electrical connection but I'm not going to bother.
I have 3 cabs I will be doing this to:
A Marshall 1936 2x12 [Celestion G12t-75s]
Marshall 1960a [on the left] [Celestion G12t-75s]
Marshall 25/51 [Celestion G12m-70s]
Of them, the 1936 is the most modded by me already. I got it for like $150, only scraps of tolex on it and spray painted black. I used to work for a foam fabricator and they were ditching a pile of fabric - I got a roll of vinyl for like $30.Yeah it's kinda pink. Whatever, it looks better. Like it's trying to be classy but it's not.
Also, the purple 1960a that has been signed by Jim Marshall may be here at the studio on the same day and may get the same treatment - we'll see if it's raining on that day because the fool who owns it lives in British Columbia, bought a truck to haul his band gear around... and never got a canopy for it.
While I have only ever heard of people doing this to Marshall cabs, I don't see why it doesn't apply to every other brand of closed-back cabinets. Basically what it boils down to is making everything as tight as possible so that your cabinet doesn't rattle and is airtight on the inside so your sound is forced to go in the intended direction.
The band is coming out for the 24-27 of this month, so that is when this will happen [I'm getting them to help me do some studio stuff in return for a recording of their new track]. I shall keep you updated on the outcome!
Other projects I am getting ready to do and will post how-to's and if it was worth doings:
~Building a badass drum riser - I have actually built the majority of it but am broke so I haven't done the final steps yet. Not guitar related but not a bad idea if you jam at your own place. It really cuts down on bass frequency transmission [the ones that big the neighbors] and makes the drums sound tighter.
~Retolexing - I am going to be tolexing several things in a few months. I'm really good at it and will post an in-depth how to with lots of pictures! I will be redoing a Marshall JCM900 head in black tolex; my Warwick bass cab in silver python; a 4 space rack case I am building for my bass head also in silver python; and a TOP SECRET PROJECT I have been planning on for 5 years and started building new year's day.