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Discussion Starter #1
I finished installing an upgraded stereo in my 17 Evora 400. The sub-woofer amplifier died so I decided to replace that with a JL RD 400/4 amplifier a JL Audio 8W1v3-4 subwoofer and JL C5-525 component front speakers. I kept the factory Alpine head unit. I’m very pleased with the results. Thanks to everyone that answered my questions and to people who had posted about their experiences with this time-consuming process- there is a lot of very valuable information here. In the interests of contributing to the group I’ve noted a few issues below that might be of use to others considering replacing all of these components.

  • You need to get the low-level line out connector for the alpine headunit- the factory set up only comes with a small one for video and sub woofer. This is necessary if you want to use the low level RCA outputs for both the front speakers and the subwoofer- this enables control of the sub woofer level from the headunit which is necessary if you listen to different kinds of music. This is what I bought (although the price has gone up):
  • ALPINE INE-NAV60 INENAV60 GENUINE RCA HARNESS *PAY TODAY SHIPS TODAY* | eBay
  • The 8 inch JL subwoofer with screws around speaker won’t fit in the factory box-the factory subwoofer screw holes are on tabs that extend out from the edge of the speaker. To install the JL subwoofer I needed to fabricate an ABS faceplate with a smaller hole in it for the subwoofer box. I fixed this with Permatex sealant and screws.
  • JL RD400/4 probably the biggest amp that will fit in the stock position. I fabricated a bracket from aluminum and mounted this onto the existing bolts that held the old amplifier. I then used velcro straps to hold the amplifier against the bracket.
  • I still needed to cut the right edge of sub woofer box to clear amplifier- there is plenty of material so this did not compromise the structure. I sanded the cut edge and added a layer of epoxy.
  • With my amplifier mounting strategy the RCA jacks on amp close to steel frame- if I did this again I would look for RCA cables with shorter jacks.
  • I wired the power to the amplifier separately instead of splicing together the power wires from the existing connector. I went through trunk release grommet and in at top by rear window- will probably re wire this through the lower engine compartment when I have the car on the lift to do the spring oil change.
  • The amplifier ground was finicky- I ended up using one of the child seat anchors that bots directly into the aluminum subframe. The steel frame does not work well.
  • I ran the RCA cable through center console to the head unit- this is a major undertaking to disassemble.
  • I ran the left and right speaker wires run up the sills under the carpet and tied them to existing wiring.
  • I mounted the crossovers high on door pillar- these are attached with Velcro. The JL crossovers are surprisingly large.
  • When threading the speaker wire from the doors I needed to remove foam packing from inside door pillar to thread door speaker wire through. There is also a tubular piece of foam that holds the wires into the hole in the door pillar- this also needs to come out.
  • The factory tweeters are glued in- the bottom of the pillar trim has a shelf across half of the tweeter hole. The key here is that the tweeters have label on back that is what most of the glue attaches to so you can slide a blade under the label and release this from the back of the tweeter. It is now possible to push tweeter out by putting pressure on side that is not glued down. If the tweeters didn't have the label on the back I think they could be quite difficult to get out.
  • Having removed the tweeter I needed to Dremel the “shelf” off to flush mount tweeters using the bracket provided.
  • Irritatingly the JL Tweeters are just a bit too small for hole- ideally I would like to get some sort of a finisher. Annoying. I may do this later
  • I used Permatex to seal the door speakers to the surrounds and to mount these back into the door shell
  • I did not add a lot of dynamat- I don’t listen to music with booming bass and at my preferred volume levels everything sounds tight. However, I could see a lot of opportunities to go overboard with this.
My initial impressions are that the front speakers are immeasurably better than the factory set up. The JL tweeters can be “aimed” so I have them slightly canted towards the cabin. The subwoofer sounds great and I was fortunate that I am not getting any significant vibration so I held off dynamatting everything in sight. Mind you, the whole set up is so loud that 50% volume is more than enough for me. It sounds marginally better to me using only the front speaker low level output and letting the amplifier handle the crossover settings for the subwoofer. However, if you want to control the subwoofer from the headunit you have to use that output from the headunit and a separate channel on the amplifier. For setting it all up I downloaded an app that will generate tones at different frequencies and then used this to adjust the amplifier inputs to the point where the amplifier starts to clip the signal.

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Thanks for the write up. Nice job.
Can you post a link to the test app, or give us the name? Thanks.
 

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Discussion Starter #3
I used the frequency generator app from here:


Several of the car audio companies have paid apps that do the same thing. Its pretty cool- you can actually verify that the crossovers work. But for setting the amplifier input levels I disconnected the speakers because the noise is loud and irritating.
 

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Discussion Starter #4
For the sake of completeness, I want to add that I had an annoying low level hum that I eventually determined was because of poor grounding. So I took everything apart again and went through the lower wiring harness grommet and earthed the amp directly to the earthing point on the rear sub frame. I wish I had done this right the first time.
 

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For the sake of completeness, I want to add that I had an annoying low level hum that I eventually determined was because of poor grounding. So I took everything apart again and went through the lower wiring harness grommet and earthed the amp directly to the earthing point on the rear sub frame. I wish I had done this right the first time.
Thanks for the info... any tips on how to get to the tweeters? I am not sure where/how to start - it's the one part of the upgrade I haven't done yet.

Thanks!
 

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Discussion Starter #6
The tweeters are glued into a hole in the upper door pillar trim piece. It is held on with clips that can be released with a standard trim tool. Just apply steady pressure at the top on the window side. Once you have the trim piece out the tweeter is glued to a "shelf" behind the hole that it sits in. The Lotus manual says that the tweeter replacement requires a new trim piece but I was able to get a scalpel behind the tweeter and used that to pry it loose. My tweeters had a sticker on the back that made this easier (ie the glue was stuck to the sticker not the back of the tweeter). Most after market tweeters are deeper than the stock ones so you will need to dremel out the shelf so you have a deeper hole to mount your new tweeters in. The only thing that I was not happy with is that my new tweeters are a little smaller diameter than the ones I took out so I'd really like to find a trim ring to make everything look neater.
 

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Thanks for the details! Pulled the A trim today. RE: Trim rings, I am looking at 3D printing with PETG filament.
 

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Discussion Starter #8
Sounds like a good plan- if you do end up printing some rings I'd be interested in sharing the cost. Or if you have a file I can find somewhere local that could print them for me.
 

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Well, I did not end up needing the rings, because after pulling the A pillar covers I realized once removing my new alpine tweeters from their housings, they were literally a perfect fit in the existing mounting holes. That said, I did play around with PETG filament (20 bucks) in my Ender-3D printer (189 bucks). It is a little hard to work with, but managed to get a decent print. I think it would take a few tries to get it right and some time, but it's def a possibility...
 
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