Project Dad-Van Phase 1: The Stealth Audio Overhaul

I recently picked up a used 2021 Toyota Sienna XSE. It checks every box for a family hauler—great MPGs, tons of room, and sporty looks—except one: the audio. The stock 8-speaker non-JBL system is flat, muddy, and totally uninspiring.

I wanted concert-quality sound without losing any cargo space to a subwoofer box. Following the legendary build log by user ‘cowdog360’ on SiennaChat.com, I decided to tackle a full front-stage upgrade using his “killer value” equipment recommendations.

The Master Plan: Active Bi-Amplification

The secret sauce here isn’t just replacing speakers; it’s changing how they are powered. The stock Sienna powers the dash tweeter and door woofer off a single channel.

I’m converting this to active bi-amplification. I’ll use a 4-channel amplifier to power each of the four front speakers individually. This lets me use active crossovers to send perfectly filtered frequencies to specifically chosen drivers.

The Gear List

Taking a page directly from ‘cowdog360’s’ recommendations for high-value performers, here is the loadout:

• The Brains (Amp): Kicker KEY200.4. The “AI” amp. It’s tiny, powerful (50W x 4), and includes a microphone for auto-EQ and time alignment.

• Dash Speakers (Mid-Range): CDT Audio Unity 8.0. While many use Audiofrogs here, ‘cowdog360’ pointed out these CDTs as a “giant killer” alternative at nearly half the price. They are “wideband” speakers, meaning they handle virtually all vocals and highs without needing a separate tweeter.

• Door Speakers (Woofer): CDT Audio CL-69 SUB CF. These are 6×9″ carbon-fiber dedicated subwoofers. Since I’m not running a big box in the trunk, these will handle all the mid-bass and low-end duties right in the doors.

Installation Notes

1. Mounting the CDTs

This wasn’t exactly a drop-in affair.

• Dash: The CDT Unity 8.0s sound amazing, but they don’t have factory Toyota mounting tabs. I had to get creative with some universal backstraps (some forum members 3D print custom mounts) to get them secure under the factory grilles.
• Doors: The CDT Carbon Fiber woofers are heavy beasts. Flimsy plastic adapters won’t cut it. I followed the forum advice and used heavy-duty HDPE speaker adapters (like those from Tacotunes) to make sure these woofers had a solid foundation to kick hard without rattling the door.

2. The Bi-Amp Wiring

Because Toyota hides the splitter for the front speakers deep in the dash, you can’t easily use the factory wiring for standard bi-amping.

• I used the existing factory wiring to feed the powerful new door woofers (Channels 3 & 4).
• I had to run new speaker wire from the Kicker amp directly up to the dash locations for the Unity 8.0s (Channels 1 & 2).

3. The “AI” Tuning

Once installed, I utilized the Kicker KEY’s auto-setup. You plug in the included microphone, play a specific pink noise track, and let the amp do its thing. It analyzes the response of the CDT drivers in the Sienna’s unique interior and automatically sets the EQ, time delay, and crossovers.

The Results

The combination of the CDT Carbon woofers and Unity widebands is incredible.

The Unity 8.0s on the dash raise the soundstage right to eye level—vocals are crystal clear and centered. Meanwhile, those carbon fiber 6x9s in the doors provide shockingly deep, tight bass that makes you think there’s a small sub hidden somewhere in the back.

It’s a stealth installation that looks 100% stock but sounds completely aftermarket. Huge thanks to the SiennaChat community for the roadmap!