Car audio

Quick and Cheap Car Audio Upgrade

The factory-supplied sound system for my 94 Ford Tempo sucks. I am not an audiophile. My ears don’t require a state-of-the-art music system. The quality I expected is something like an average home stereo, and I only want to spend $100 for the upgrade. It sounds impossible. Well, I managed to hook up some old stuff and make a quick and cheap upgrade. The main problems of my stock car audio were:

1. The output power of the cassette player was too low to deliver undistorted bass.

2. The stock speakers didn't response to bass well.

So, I replaced the cassette player and installed a subwoofer. The replacement cassette player is Pioneer 35W x 4. I bought it for $20 from Canadian Tires some years ago during a tent sale. The subwoofer is a pair of 25-years-old home stereo speaker in sealed enclosures. Each speaker has a 10” subwoofer and a 2” tweeter. The box each measures 21” x 13” x 10”. The rated power is 80W RMS each.

It happened to be a big improvement. The bass is tight and deep. I then added a MP3 player interface. If you have limited budget, try it. The following is details of the upgrade.

Replacing the cassette player

To remove the stock cassette player, you need a special U-shape tool (known as DIN radio removal tool. These tools are inserted into the 4 holes on your head unit (2 on each side). After inserting them, you pull them apart (away from the center of the head unit) and out toward you. Go to http://www.bcae1.com/installationprimer.htm where an animation shows you how to use the DIN tool. Or, go to www.installdr.com and download the pdf document # 356101. The document not only has pictured instructions for removing the factory radio, but also has the step-by-step instruction for hooking up the new radio. The download is free. If you are new to car audio system, download document # 999003 as well, which has a very good background information regarding wiring of car audio system.

I didn’t buy that tool. I used 4 pieces of steel shafts that salvaged from older CDROM drives. The shafts are of ¼” diameter. They work pretty well.

After removing the stock radio, you either buy a snap on "integration" wire harness adapter or identify the wires according the document # 356101. Using the snap on wire harness will safely and easily allow you to connect a new radio to the existing wires of the Ford audio system. If you choose to spice the individual wires (as I did), make sure that all speakers need to be in phase or most bass from each speaker will cancel each other. To determine if a pair of speakers in your vehicle are in phase, listen to some bass-heavy music with your stereo's balance control all the way to one side. Now return the balance control to the center — you should hear significantly more bass. If you don't, your speakers are out of phase. Switch the positive and negative leads on a single speaker, and try again. If you hear more bass, leave it! Check the front and rear speakers independently in this manner. Now the wiring connections at the radio side are confirmed correct and you can make them permanent (e.g. by crimping or soldering). Then the radio is inserted into the dash and secured with screws.

Install the subwoofer

The installation involves:

1. Removing the fiber sheet which hides the rear speaker.

2. Removing the rear speakers.

3. Hook up the subwoofers and secure them so that they won't slide around the trunk.

To remove the fiber sheet, pry the plastic pins out with a 12" flat screw driver. The plastic pins look like this.

Once the fiber sheet is removed, you can get access to the rear speakers. The rear speakers are not screw-mounted. They are held by rubber straps. Just pull the strap off the hook and remove the speaker.

The two openings will allow the bass to vent out to the driver/passenger compartment.

Then hook up the subwoofers and check if they are in phase. Also try to vary the locations for the subwoofers for best result.

Add MP3 Interface

I glued the plastic pins on the dash as a MP3 player holder. The MP3 player is hooked up to the cassette player with a cassette adapter.

MP3 Mod

The MP3 player use a AAA battery. I found that it draws around 100mA when the volume is ramped all the way up. An alkaline AAA battery only last for 2 -3 hours. I modified it so that it use external rechargeable battery pack.

1. Solder wires to the terminals in the battery compartment and drill a small hole to let the wires out.