If you’re building a blow-through speaker box setup in your truck — where the subwoofers port through a cutout between the cab and bed — there’s one detail you need to take care of: the seal between those the truck cab and the bed.
That’s where the accordion boot comes in.
This flexible, weather-resistant rubber boot creates a sealed, tunnel-like connection between your cab and bed, making it perfect for custom audio blow-throughs. The accordion boot is a smart and proven solution.
What Is a Blow-Through Truck Audio Setup?
A blow-through, or pass-through audio build, involves cutting an opening between the truck cab and bed so that a large subwoofer enclosure can push sound directly into the cabin. It’s popular modification because space inside the cab is limited.
In this setup:
- The speaker box sits in the bed
- The port points toward the cab
- A sealed opening allows bass to travel into the cab efficiently
More airflow = better pressure response = more Sound Pressure Level = louder, cleaner bass.
Why Use an Accordion Boot in a Blow-Through?
When you cut an opening between the cab and bed, you create a big problem: exposure. Rain, dust, road debris, and even engine noise can easily find their way into your cab — unless you seal it properly.
That’s where the accordion boot shines. Originally designed to connect truck cabs to camper shells, it’s become a favorite among car audio enthusiasts for blow-through builds.
Benefits of Using an Accordion Boot:
- Creates a sealed, flexible tunnel between cab and bed
- Protects speaker box and cab from weather, dust, and debris
- Improves sound pressure efficiency
- Reduces flexing and air leaks at high volume
- Clean, professional finish to your build
How to Install an Accordion Boot for an Audio Blow-Through
Step 1: Cut Your Opening
- Measure and mark your blow-through port size
- Use a jigsaw or reciprocating saw to cut openings in both the rear cab wall and front bed wall
- Be sure the edges match up cleanly to ensure a good seal
Step 2: Measure the Gap
- Measure the distance between the cab and bed walls
- Also measure the perimeter of the cutout on both sides
- Use our Boot Opening Calculator to get accurate perimeter sizing
Step 3: Install the Accordion Boot
- Clean the mounting surfaces thoroughly
- Slide the spring steel edge of the boot over the flanges of each opening (cab and bed)
- Use silicone sealant if needed for added waterproofing
- Compress the boot slightly to create tension and a tight seal
You can also secure with self-tapping screws or clamps for extra hold — especially in high Sound Pressure Level builds.
Get the Right Accordion Boot for Your Build
Our accordion boots are made from heavy-duty black EPDM rubber with a spring steel clip around the inside edge — built to flex and seal in even the most aggressive audio environments.
Need help choosing the right size?
Use our Boot Opening Calculator » or Contact Us »
Final Thoughts: Seal It Right, Bass It Better
If you’re serious about your blow-through audio setup, don’t leave the cab-to-bed opening exposed. A quality accordion boot gives you the performance, protection, and polish your truck audio build deserves.
Whether you’re daily driving or competing in SPL shows, sealing the gap makes all the difference.