A repeat client from Wyndmere recently contacted Audio Garage to inquire about installing a stereo system upgrade in his 2020 Peterbilt 389. This client comes to us every three years or so to upgrade his new truck. After inspecting the new rig to determine speaker sizes and to scout locations for a subwoofer and amplifiers, we designed a sound system that would deliver the clarity and output that he wanted. Keep reading to find out how we transformed this big rig into a mobile living room with an amazing audio system.
Kenwood Source Unit
We started the upgrade by removing the factory radio to make way for a Kenwood KDC-X702 CD receiver. The new radio fit into the lower portion of the dash perfectly and provides the client with HD Radio, CD playback and Bluetooth audio streaming and hands-free calling. We added a USB port to the center console so the client can charge his phone or play music. He can also connect a USB memory stick to play MP3, WMA, AAC, WAV or FLAC digital audio files. Finally, we upgraded the radio with a SiriusXM SXV300 satellite radio tuner so he can listen to whatever genre of music he wants almost anywhere in North America without interruption.
Big Rig Speaker and Subwoofer Upgrades
The next step was to upgrade the speakers in the truck. The client chose two sets of Infinity Kappa speakers after listening to them on our display board. We used a set of Kappa 64CFX 2-way 4×6 plates for the front of the cab and a pair of Kappa 62IX 6.5-inch coaxials for lower B-pillar locations. Infinity speakers include a feature called Plus One technology which, in essence, means the speakers use a larger-than-normal woofer to increase the overall efficiency and bass performance. Our clients love the way they sound — and their price.
Next on the list was the creation of a custom subwoofer enclosure. We built a vented cabinet that would fit in the storage compartment under the bed in the sleeper. The enclosure is home to a single 12-inch JL Audio 12TW3-D4 subwoofer. The vented design increases efficiency at low frequencies while reducing distortion. We added an SGR-12TW3 mesh grille to ensure it won’t be damaged if the driver puts anything in front of the cone.
JL Audio System Amplifiers Deliver Big Sound
The last step in upgrading the stereo in this Peterbilt 389 was to install a pair of JL Audio XD-Series amplifiers. We started by running 4-AWG power wire from the battery bank to a MESA fused power and ground distribution block. From there, 4-AWG runs lead to each of the amplifiers to ensure they get all the voltage and current they need to sound amazing, even at higher volumes. We wrapped the power, speaker and interconnect cables with automotive-grade fleece tape to keep them from buzzing or rattling as the rig travels down the road.
A JL Audio XD300/1v2 monoblock subwoofer amplifier is attached to the end of the subwoofer enclosure and powers the 12-inch subwoofer with up to 300 watts of power. We mounted a matching XD400/4v2 four-channel system amplifier to the left of the distribution block. This amp delivers up to 75 watts to each of the front and rear speakers.
Upgraded Peterbilt Stereo Provides Hours of Listening Enjoyment
The last step was to dial in the amplifiers to work with the new radio, the Infinity speakers and the JL subwoofer. We were able to keep the sensitivity controls on the amps down nice and low, thanks to the strong 5-volt preamp stage of the Kenwood source unit. We tuned the crossovers and level controls for the subwoofer and front and rear speakers to deliver smooth and natural frequency response.
After three days of work, it was time for the client to return to Audio Garage in Fargo to pick up his Peterbilt 389 and listen to the stereo for the first time. He was thrilled with the sound and loved the deep bass extension and clarity of the new speakers. If you are interested in upgrading the sound system in your vehicle, drop our store, give us a call or send our team an e-mail using our online contact form.