Dynamat installation and pre-wiring for amplifiers

So a couple of weeks ago we made some major headway on the project.  Matt Freeman, our mobile electronics catalog editor and Michael Richardson, Crutchfield mobile installer extraordinaire, and I spent a day double-lining each door with Dynamat Xtreme and routing the 1/0 Streetwires Ultra Flow power cable into the truck. 

Double-lining the doors might sound like overkill, but by clamping down on the vibrations of the actual skin of the vehicle, you're really taking a serious bite out of road noise. Couple that with a solid sonic barrier on the interior panel (and covered gaps in the framing) and you add the benefits of increased isolation from external noise, reduction/elimination of internal buzzing and rattling, and better sound damping within the cab. 

Instant luxury car

The difference was immediately apparent upon climbing into the front seat at the end of a pleasant day's work. Before we even turned on the stereo, we could "hear" the quiet. It felt like being in a professional recording studio. I popped in a disc of some of our final and near-final mixes. For the first time I could hear bass guitar articulations previously inaudible. The upper midrange was much more sculpted and clean, thanks to the reduction in reflections and reverberations. I turned the key. Engine noise was no problem; I could still hear everything clearly, without notching up the modest volume level, allowing  Matt and I to share thoughts - in conversational tones — about what we were hearing.

The GMC Yukon became a Lincoln Navigator. Stereo or no stereo, I highly recommend an application of Dynamat to transform your ride to a dead-quiet one. I wish I had taken a before/after dB reading. I have no doubt we'd have seen at least a 3 dB difference.

Prewiring for the amplifier installation

Michael found a location high and to the right of the brake master cylinder with plenty of surface area into which he could drill a hole big enough to accommodate the garden hose-sized power cable we ran from the battery to the rear of the truck. The original plan was to put both planned amplifiers (a 4-channel for the 2 sets of speakers and a sub amp) in the cavernous space under the rear bench seats. However, Michael astutely demonstrated how the rear seats fold collapse down and fold forward, giving me a Chevy Suburban-like cargo area. Given the potential need to haul music gear, I'm sold on the idea of keeping the floor clear.

So now I'm thinking about putting amplification in the rear quarter panel storage area. There isn't room for two amps, though, so I'll either have to find a spot for a second amp elsewhere or rethink the need for two amps. (I really want a stealthy installation.) It's possible I could get a 4-channel amp to drive the front components and the subwoofer, while relying on the Alpine CDA-9887 head unit's internal power for the rear door speakers.

I'm open to suggestions.

(Oh, and thanks to Jason, a loyal customer who contacted me with some great ideas from his Tahoe installation and generous offer of service manual info. I'll be in touch.)

Pictures from the day:

Super-installer Michael Richardson is so smooth with the
knife that he applies Dynamat with left-to right readability,
no visible seams, and an absolute minimum of wrinkles
(above). He readily acknowledges that no one will see
his perfect work once the door panels are re-hung, but
for him it’s a higher calling. (While I was satisfied with
my own work, rest assured I won’t be posting any
pictures of it.)

The same door with the panel back on, before re-attaching
the sail panel. Michael’s super-clean work is again apparent.

The inside of the Yukon’s left front door panel. You can
see the cut-out for the woofer (mounted in the door frame)
and the actual tweeter mounted in the panel itself.

This picture demonstrates the way we cut pieces of Dynamat
Xtreme to fit within the bracing. We also have a Dynamat hoodliner
we'll add later.

Here’s the right rear door with the panel removed, just
prior to an application of Dynamat. Note the factory
whizzer cone speaker with fabric stretched across the driver.

I took that speaker out in order to fully cover the factory
opening in the door frame (at Michael Richardson’s
excellent suggestion). I was then able to cut a hole
for the speaker in the Dynamat itself and drop the
speaker back in, thus ensuring a solid seal behind
the speaker. No noise or air is getting around that thing
now. Can’t wait to put some “real” speakers in there soon.

Remember I mentioned double lining? The left rear door
was the first one we did – before deciding to double line.
Therefore, I had to piece the material in behind what I had
previously installed – to cover pretty much the entire skin
of the door (ouch). Oops, I said I wasn’t going to show you
my work …

We chose to route the power wire straight back from the
battery to the firewall on the right-hand side of the engine
compartment.

Ultra Flow cable feeding into the vehicle’s cab via a hole
drilled into the firewall.

The cable comes through on the driver’s side.

Read the entire Building a Mobile Listening Lab series:

1. Laying the Foundation, Part 1
2. Laying the Foundation, Part 2
3. Laying the Foundation, Part 3
4. Dynamat installation and pre-wiring for amplifiers
5. Installing the front door speakers
6. Video: factory vs. aftermarket speakers
7. Rear speakers, amplifier, and subwoofer
8. Report on the Yukon system's performance
9. The ultimate in system tuning
10. Video: Alpine's IMPRINT signal processing in action