DSmith1178

The spacer is a 3/4" made out of mdf. I bought it on ebay for like $9. Was a perfect fit. I went with a two channel amp to bridge it into one output to give me more wattage to the sub. It didnt work as I hoped. Bridging the PBR300x2 into one channel was sending over 300 watts to the JL (375 to be exact according to the rockford fosgate power certificate that they supply with their amps). I could tell almost immediatley that I was overpowering the sub which is rated for 75-250 watts. 375 watts to that sub and it wont last very long. I had a ton of vibration from the stock enclosure which I padded with alot of foam padding. It didnt sound good at all. Very boomy and muddy, and that was with the gain turned all the way down. I ditched the one channel bridging idea and now am running the sub on one channel of the two channl amp which is about 140 watts. So far it sounds way better but I still need to play around with the gain and crossover settings to really dial it in. The sub sounds much happier running at the lower wattage. Still have a little vibration things in the back of the jeep that Ill have to try and quiet down. Was it worth it??? Not sure yet but will play with the settings and work on dialing it in. Its definatley a smoother bass sound then the Infinity. I want to buy the Rockford remote control for the amp to be able to turn the sub volume up and down from the driver seat. That will help in on the go adjustment.

Dave

ranjr

I see that the JL 8W3 is only available as 4ohm. I had thought of using the PBR300.1 but it won't put out enough power into 4ohms. A DVC sub sounds like the best option if using the PBR amps.

DSmith1178

What I learned today is that the 8w3 doesnt need a ton of power. 125-175 watts is more than enough to power it to get desirable results. Another thing about the PBR300x2........ It gets HOT!! Im wondering if keeping it in the storage well in the back of the jeep is gonna give me issues. Time will tell.

Freewill

Efficiency is a good thing, 'specially for speakers that aren't powered from the grid.

Interesting that the 8w3 gets hot. Heat is what kills speakers. The glue holding the voice coil, coil former, and cone together comes apart with heat. You end up with a handful of copper and cardboard. I've seen speakers smoke and catch fire, but only when everyone was having way too much fun

FYI, its good to think of power in terms of doubling or halving. In other words, the power must double for each noticeable difference in performance.

Freewill

Its true that a 4 ohm speaker pulls less power from the amp than a 2 ohm speaker. But if the 4 ohm speaker is more efficient than the 2 ohm speaker, it could still give the most thump.

Most speakers have an efficiency rating like 85db or 92db or even as high as 100+ db. A speaker with a 92db efficiency rating is louder at 100 watts than a speaker with 85db rating at 200 watts.

ranjr

The 8W-3 is 83db which is about average for this size.

Patman

The amp is what got hot, not the sub

Imoutdoorsy

Dave can you post Ebay Seller on the spacer?

DSmith1178

It was ennis_electronics_151. Fast shipping and the spacer fit the enclosure perfectly and the JL 8w3 I put in.

Freewill

Thot you were talking about a speaker. Its all good - gave me a chance to talk about smoking and burning speakers - haven't thought about that in years

If the amp sits in the under-floor compartment and runs hot you might need to move air through the compartment somehow.