As another approach, I went simple this time and bought the Kenwood speaker backbox kit from pinballlife and the Boom Boom woofer, which is kind of like DIY but everything comes ready with the connectors to just swap out. I have tried most other makers kits including Flipper Fidelity, PinWoofer Pinwoofer, and Pinball Pro. I like all of them but I really like what Dan is doing with the Pinwoofer system and have that in another game and may go that route for this game at some point when the funds are available as I like the top end kit.
Another few tweaks/upgrades you can do after you change out the speakers is go into UTIL/VOL and change some settings. I switched to 4 ohms with my 4 Ohm speakers, I just found that sound cleaner than the 8ohm setting, but it seems different for others as with 8 ohms it is kind of like a low end boost at low volume levels.
I don't have the menus in front of me right now but there is another setting that you can change from a HIGH/LOW split of EQ to a graphic EG and then adjust each frequency separately. You can dial this in for the cabinet speaker and the backbox separately which really helps. I roll off anything below 125Hz on the backbox and push up above 2khz. For the cabinet speaker I roll off anything above 500hz gradually and by the time to get to the highest frequency slider it is off. Then I push up from 62hz to 250hz. I don't push up and actually pull the 32hz down about 6db as it just adds noise and overdrives the cabinet speaker.
Then I tweak the fade between the cabinet speaker and backbox to pull up the cabinet speaker some to balance the sound. I have my shaker set to Minimal as I am on a wood floor that is no ground level. There are more settings in there you can play with as well that I may have missed since it is not in front of me.
Quoted from Drain-O:
I'm really considering doing a little do-it-yourself upgrade on the speakers in my cabinet.. But I'm also a total novice... So, two quick questions, what type of wires do I need to buy to attach to the speakers, and what do you call the white plastic thing that the wires are going into that connects to the other white plastic thing, and where do I get those? Sorry for being so new to this stuff -- I'm perfectly capable of doing all the work, just don't know what anything is called.