Received my Final Resistance module this week which motivated me to finally upgrade the P3 sound system. The P3 is innovative in so many areas, but the sound system isn't one of them. The base system uses Alibaba speakers with a small Multimorphic amp board. The speakers are similar quality to Stern pros/premiums and maybe a step down from the Stern LE, JJP and API systems.
I'm far from a sound expert, but have a couple PinWoofer systems, and installed DIY systems on my other Stern premiums and LE's after reading through the Pinside DIY sound thread. Both yielded similar, major improvements, but the DIY approach is less than 1/2 the cost. And Pinwoofer doesn't offer a system for the P3.
I'm thrilled with the results, and it's particularly amazing on FIRE given Scott's soundtrack. The whole thing cost less than $150 and takes it to another level.
You could also just install new speakers for less than $100 and use the existing Multimorphic amp. May give a big chunk of the improvement, but I don't know how it would sound without being able to balance back box and cabinet volumes.
Here's a summary of what I did with a big caveat to proceed at your own risk, especially if your machine is still under warranty. I installed a separate 24V power supply and amplifier so the changes actually have no interaction with the P3 other than picking up 110V line power and the audio out jack - but would be very careful if you don't really understand working with electricity and how everything works/comes together. I also have an earlier P3 without the new speaker panel which could make a difference in clearances, speaker selection, etc.
The back box speakers are 6.5". I've used Flipper Fidelity, Pinsound, Pinwoofer, Pinball Pro, Pyle and some other brands over the years. They're all an improvement but have settled on the Infinity Reference Series. They're about $70 on amazon, but you can usually buy "like new" for $40-50. The bolt pattern is a direct fit. It may not be needed but I installed a 1/4" speaker gasket as a spacer. You could also 3D print a spacer. There's plenty of room in my version of the P3 but I still ordered the shallow mount speakers. People on the DIY thread also really like Kickers -sure both sound great and night-and-day from stock. https://www.amazon.com/gp/product/B07YYPF593/ref=ppx_yo_dt_b_search_asin_title
I had an 8" Flipper Fidelity 4 ohm woofer on-hand so installed it in the cabinet. It sounds really good, but I plan to replace with a Goldwood GW-8024 that's on order. I'm almost certain that the Flipper Fidelity is a cheaper GW-208 with a paper cone, which is the same speaker in the Stern LE. The FF is $35, GW-208 $30 and GW-8024 $40 (or $33 if you buy 2 direct from Goldwood). People on the DIY thread really like JBL Stage subs, and that's what BOF is using in Labyrinth, but I prefer a wider frequency range woofer vs. subwoofer. The FF and Goldwoods are about 25-6000 Hz while the JBL only goes up to 200 Hz. Subs can also be a lot more power hungry to sound good. I installed a 1/2" spacer for the woofer. https://www.amazon.com/dp/B000HJ0S88/
For the amp I used a DAMGOO 50W+50W+100W from Amazon. It's only $26 but has knockoff TI sound chips used in higher priced amps. I installed the Fosi BT30D pro amp that the DIY sound guys love, $80-100, in one of my Sterns and honestly can't hear any difference. The DAMGOO gets great reviews on Amazon, and has more than enough power, easy install and no feedback issues. You could also use a Lepai DP-168HA amp like American Pinball and Spooky for about the same cost, but from what I understand it has lower quality circuitry. I just got a basic 6' 3.5mm M/F extension cable to extend the jack from the existing MM amp to new one. https://www.amazon.com/gp/product/B089KT3FG9/ref=ppx_yo_dt_b_search_asin_title https://www.amazon.com/dp/B01CNAUYBY
I used a Meanwell 24V switching power supply that's $27 to power the amp. It's the same type as Multimorphic uses for 12V power in the P3. It's important to use a supply that matches the amp's rated input voltage so that it's not starved for power. I tapped the 110V input for the amp from the P3 power switch. You could pick-up 110V from the P3 12V amp but again I wanted to be cautious and keep things separate. You could also use a properly rated power adapter/brick, cut off the plug and wire into the P3 power switch or just plug into the service outlet. Make sure to unplug the P3 from the wall outlet when doing any work in the cabinet, and be careful where you place the power supply and amp since there's not much clearance between the modules and cabinet bottom. https://www.amazon.com/dp/B018RE4CWW
Hope this helps some of you.
IMG_3882 2 Large (resized).jpegIMG_3883 2 Large (resized).jpegIMG_3884 2 Large (resized).jpegIMG_3881 2 Large (resized).jpeg