Finally wrapping up my audio upgrade, maybe this info helps you

Julio_E · Jun 24, 2025

I did find search result posts here in Priuschat forum about some folks trying it under the seat. Search 'woofer' in the Gen5 forums and you should get some results that you can skim thru and probably find references to under the seat. It's been awhile since I read thru those but back when I did that, my take from those posts were certain small woofers like the Nano either would not fit or would be extremely tight in the Gen5 Prius. I think I also recall reading of someone else here on Priuschat that did manage to get some thinner smaller woofer under a car seat (may not necessarily have been the Gen5 Prius), but then removed it from there because their passengers didn't like the bass vibrations rumbling they felt while sitting in that seat. I don't think I'd like that either and so because of my overall take on this, I didn't even try that under seat option. Of course opinions differ so YMMV. Therefore, for the Nano and for me, it was either going to be under the cargo area or somewhere above the cargo area.

Here's an example search result that mentions under the seat and the OP's pictures and last posts look like the original under the seat plan was nixed in favor of behind the passenger seat. Gen 5 Prime XSE Premium - Adding a powered subwoofer to the JBL system and need advice | PriusChat

PrismPopo · Mar 15, 2026 at 9:54 AM

soft_r said: ↑

Tips:

Feed your own wires from behind the stereo to the tweeters. It's not hard, you can use a thin stick to tape the wire to and push it through the opening in the dash behind the stereo to each tweeter. This allows you to have your tweeters on your wires and they'll be disconnected from factory wiring. Your front and rear doors will stay connected to factory wiring. Now you have individual control over all 3 sets of speakers.

If you're installing your own amp, just use OFC copper. Go to Lowes/Home Depot. It's less than $2/ft for 4awg. Do it right the first time and don't cheap out with CCA wiring.

Run your speaker wires to the left under the dash, down the driver side kick panels. Not the right side. Keeps them away from HV lines and the battery on the right. Less potential interference.

I suggest something like a Kicker KEYLOC to help you get a flat clean signal to your amp. There's definitely some cleanup to be done to get rid of the factory tuning.

The mechanical latch wires for the doors resonate at certain frequencies. It can be annoying. Usually stuff below 400hz gets them vibrating. Really you just have to tape them down everywhere. Still not a perfect solve but it does help.

I've finally settled on a JL Audio VXi600/6i and a NVX VAD10001 to power the subwoofer. I had a custom trunk cover made so if you looked in my trunk right now it looks totally normal. Wouldn't know that under the flooring is my amp setup.

Speakers and why I chose them...
Dash = CDT Audio Unity 8.0: These have good off-axis (ie. not facing directly at you) response which you want given that these are in dash speakers. They are WIDEBAND drivers, not just tweeters. They aren't screechy, they sound great IMO. People say the 7.5 have better off axis response but honestly these sound great and didn't need a ton of EQ to level them out.

Front doors = TM65 mkIV Midbass: Everything I read about them had people praising them with only the best things to say. Honestly I'm not THAT blown away by them but they certainly don't sound bad. It could just be their location that hinders things. And I've tried many crossover points with them. They are JUST good speakers but not worth $300+ for the set IMO (I got mine on sale). But again, might be their location in the door that doesn't allow them to reach full potential.

Rear doors = Alpine S2-S65C: This is the COMPONENT version. There is a coax version as well, which honestly since I'm doing rear fill maybe I should've gone with coax but whatever. This was just on sale, I've had good personal experience with Alpine products in the past and it didn't need to be an exceptional speaker in the rear because I'm just doing rear fill. I have no complaints.

Technicals...

Measurements were done with a Behringer ECM8000 microphone, calibration file loaded for it, run through an Apple USB-C DAC (sounds silly but it is actually a really clean little adapter).

I am not a professional anything and I have not had a "professional tune" done. This is all me from trial and error and learning and experimenting and what sounds best to me.

If you're doing a driver-only tune, then by measurement at mic you need to subtract 2.5dB from all driver side speakers. Personally from my listening I felt like -4dB sounded better.

Crossovers are (currently):

Dash - 1,000hz @ 12dB LR

Because they are widebands I felt comfortable crossing them this low. And the measured audio response was still fine from them. Will probably settle at 1.2khz though.

Front Doors - 80hz @ 24dB LR / 1,000hz @ 12dB LR

Could go lower but we have a subwoofer for those, and because the speaker is at our ankle I didn't like more directional frequencies being down there.

Rear Doors - 333hz @ 48dB LR / 3,000hz @ 12dB LR

Rear doors are doing DIFFERENTIAL REAR FILL. Hence why they are handling this odd frequency range.

Sub - 31hz @ 48dB LR / 60hz @ 24dB LR

Because people (myself especially) listens to the sub louder than the rest of the components 60hz felt more appropriate. By the time we hit the 80hz crossover of the front doors it blends nicely. Also my high pass filter is 31hz @ 48 because the tuning of my subwoofer is 42hz so 31hz allows me to play max at its tuning frequency and then sharply drop off on lower frequencies which may damage it if they're too loud.

Timings are (Left/Right, in miliseconds):

Dash - 0.78/0

Front Doors - 1.21/0.09

Rear Doors - 1.95/0.61

It's suggested to add extra delay to the rears when doing rear fill but I didn't feel it was necessary. I played with it a bit and just didn't feel a need to add additional delay beyond the standard for distance. Sound stage is still nicely up front.

Subwoofer - 0.57

Subwoofer is a down firing low profile sub in the trunk area. I set its delay by playing pink noise from it and the front door speakers (setting the sub crossover to 80hz instead of 60hz for this), and then I inverted the polarity of the subwoofer and adjusted timings until I found the greatest dip (cancellation) in my frequency measuring. Then I flipped the polarity back to normal on the sub. That got me perfectly phase aligned sub to front door sound.

Click to expand...

Hello! Despite this post being 2 years old, it has been pretty darn helpful. I'm planning a similar setup as yours (same amp, changing doors and dash speakers, and running wire to the dash so that doors are on their own channels). Also I'm not doing a subwoofer yet.

My question is: What gauge wire did you run from the JL Audio VXi600/6i amp out back to the harness/dash speakers? I was thinking to get the 26ft harness extension from autoharness (item number: AHH-2477LONG), but wanted to know what you did. Thanks!

soft_r · Mar 16, 2026 at 2:57 AM

PrismPopo said: ↑

Hello! Despite this post being 2 years old, it has been pretty darn helpful. I'm planning a similar setup as yours (same amp, changing doors and dash speakers, and running wire to the dash so that doors are on their own channels). Also I'm not doing a subwoofer yet.

My question is: What gauge wire did you run from the JL Audio VXi600/6i amp out back to the harness/dash speakers? I was thinking to get the 26ft harness extension from autoharness (item number: AHH-2477LONG), but wanted to know what you did. Thanks!
Click to expand...

I did 18awg CCA, which is honestly not great. This was done when I had a single amp, not the vxi, and was pushing less power. This spring I'll actually be redoing that run with 16awg tinned copper. Something like 16 AWG 12 Conductor Unshielded Multi Conductor Cable

The dash speakers to the harness are both 16awg.

From the stereo I have a short wire run from the harness Front L/R +/-, so 4 wires that go into my keyloc.
From the keyloc is two heavily shielded RCA cables back to the trunk to the vxi amp.
vxi has the 18awg run up to the front. It's sending 6 channels (DashL, DashR, FrontL, FrontR, RearL, RearR). So that's 12 wires, plus a remote wire as my amp turn on trigger (personal preference, I just like the amp to have power immediately instead of waiting for it to sense it through other methods).

The autoharness wire isn't a bad idea but it's only going to be sending 4 channels over 8 wires. So you'll need an additional run of 4 wires next to it for your dash speakers. Not a big deal really but it just makes it less "clean" as far as the wire run. If that's not an issue though do contact autoharness and ask them if the wire is at least 16/18awg ofc/tinned copper. If it's a combination of those then it should be just fine. If it's CCA or aluminum or 20/22awg then I'd pass on it. I'm curious as to what it is as well. It's priced like it's about 16awg copper.

Finally wrapping up my audio upgrade, maybe this info helps you

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Finally wrapping up my audio upgrade, maybe this info helps you

Julio_E Junior Member

PrismPopo New Member

soft_r Active Member