Fixing the Prius ground loop hum without sacrificing audio quality.
There's nothing quite like tech envy for someone obsessed with gadgets. When my non-tech savvy friend showed off her iPhone paired with her A2DP stereo system in her Kia Optima, I knew that I was behind the curve. But there's no way I was installing a new stereo or, worse yet, buying a new car for this set up.
That's when I stumbled across the perfect DIY solution for A2DP! This Blackberry bluetooth gateway plugs into a power source and then end of an aux-in jack (which I also had to DIY with a GROM adapter into my Prius when I first got it). Using this wonderful gadget that turns one car charger into two and two USB ports, a mini USB type B cable, and the adapter, I had everything set up in my glove compartment and good to go in no time...
Blackberry Stereo Gateway
...until I turned it on and discovered the bane of the Prius stereo system: ground loop hum. Because of the electronics within the Prius, anything connected to both a power cable and an audio cable simultaneously tends to emit a shrieking, high-pitched whine that requires a psychiatrist's help to remove the splitting headache caused by the noise.
Google referred me to a series of PriusChat posts recommending a ground loop isolator. The recommendations came with a warning of supposedly slightly reducing sound quality, but the highest quality one was supposedly on Crutchfield by PAC, so that's the one I got--although, I purchased mine from Amazon.
I was more than disappointed when I plugged it in and my audio sounded clear but much lower quality. Despite the whine, I was originally in awe of the quality of the bluetooth set up. It sounded pretty good until I attached the ground loop isolator! I knew this quality-reducing solution wouldn't work.
This is the point where I finally decided to use my own brain. It surprised me when it came up with the idea of a ferrite choke. At $1 and some change from Digi-Key, it surely couldn't be wrong to give it a try, so I ordered three!
I waited a couple days and, when they arrived, I attached them all and turned the car on. I began to accelerate with bated breath - would the hum appear when the engine kicked on? The engine whined into existence, but the sound coming from the cranked-up stereo remained crystal clear and clean! Tada! I eventually removed different chokes to test the effects, and found the one pictured below with the mini USB cable wrapped several times through it to be the most effective:
Prius USB cable choked (click for bigger image).,
Now I'm happy! My solution works as good as an integrated solution in a stereo, and I have the massive satisfaction of having done it myself. Not to mention the cost savings of a $60 solution. BAM! (Sorry, that's the satisfaction of my tech envy coming out!)
Front Speaker Upgrade to 1996 Subaru Legacy Outback
After being constantly annoyed by the awful-sounding front speakers in my 1996 Subaru Legacy Outback (the rear speakers had already been replaced), I decided to buy the Polk Audio db6501 component speaker system. I found it on Crutchfield, but I wasn't about to pay $200 for it when it was $110 on SonicElectronix.
The speaker system, being a "component system", includes main speakers (woofers) that go in the traditional speaker spot inside the door, little circular speakers (tweeters) that had to be mounted somewhere on the pillars, dash, or sail panel, and finally the crossovers that separate the audio feed to both the woofer and tweeter.
My dad has done audio mods before (the aforementioned rear speakers), so I waited until this weekend for him to be free.
The entire installation went rather smoothly, and took about 4-5 hours. It began with:
1. Removing the inside door panels. This was relatively simple, just going around the edges of the door with a flathead screwdriver popping out a bunch of clips. I also had to remove a few screws.
After the clips were popped, it was as simple as gently pulling the panels up and off and popping out the power window panels.
I set the panels aside and didn't use them again until I installed the crossover in step 5 and 6.
Door Panels Removed (Click for bigger image)
2. Removing the old woofer. This was as easy as unscrewing them from the mount. That made it easy for the next step.
3. Mounting the new woofer. The new woofer had to be attached to a mount included with the system, which was then attached to the Subaru mount.
Polk Audio Woofer Installed (Click for bigger image)
4. Mounting the tweeters. I decided to surface-mount the tweeter on the door sail panel as shown:
Tweeter installed (Click for bigger image)
5. Feeding all of the wires into the door panel. The previously removed door panels had a storage area, so I drilled a hole into it and fed the wires through it. The crossover will be placed in here. While feeding the wires through, it was easy to snap the door panels back on in the same step.
6. Wiring the crossover. My dad stripped the ends of the wires for the tweeter, woofer, and input and put them into their spots in the crossover.
7. Mounting the crossover. As mentioned previously, the crossover was going to be stored in the door panel's storage area. But they are not supposed to be loose as vibrations can be damaging. So I took some velcro strips and used them to stick the crossover to the side of the storage area in the door panels.
Crossover Installed (Click for bigger image)
Project Complete! (Click for bigger image)
Project complete! My dad and I were surprised how amazingly smoothly it went. And the sound: absolutely awesome. These speakers are well worth the upgrade from the stock audio!