Head Unit selection can make or break a system. Generally, people devote too little time and effort to the purchase of new head unit, and because of this, they end up being limited in the capabilities of their systems. I have owned a great many head units, and have had even more in my car for evaluation purposes. Those that I can remember include the following:
Coustic AM/FM Cassette (only there for a week)
Sony CD player (no tuner), (again, only a week)
Many of these units represented a certain 'top of the line' position in their respective price and feature categories. And many of them are considered the flagship models for that particular manufacturer. As you can see, I am have used a great many Alpine and Clarion units, and have switched back and forth between them consistently over the past
So, what's the difference between all these units? Accurate reproduction is our primary goal for a competition audio system. All the units you audition for your car have certain requirements that must be met to be considered for your system. The list is as follows:
Ease of use. A deck with too many menu's or modes is difficult to learn and operate. Stick with simple controls
Good Specs. You can try and compare head units by the numbers, but it won't be easy.
Reliability. You need to know that your investment is going to last for along time.
The biggest differences I have ever come across between similarly priced equipment have been in speakers and head units. The story goes like this...
I was fortunate enough to get the opportunity to purchase my father's car, and let him trade mine in on the new car he wished to buy. (mine was a '91 Mazda 323, his was an '89 Mazda MX-6, and he wanted to buy a '95 Mustang GT). The system in the MX-6 used an Alpine 7915 when I purchased it from him. I installed the equipment from the 323 into the MX-6 and left the head unit alone until I was ready to build the system in the Mustang. Once I started work on the Mustang, I removed the 7915, and installed my Clarion 5790. I had a quick listen to some reference disks (reference to me that is!) to make sure there was no noise, and all levels and connections were proper. WELL!!! The difference in the image on the windshield was astonishing. With the Alpine, Jennifer Warnes voice appeared to come from a sphere about the size of a softball in the center of the windshield. When I listened to the same track at the same volume with the Clarion, her voice was about the width of a computer keyboard. And a great deal of definition was gone. I was astonished. A measly $500 Alpine had blasted my thousand dollar Clarion to bits.
This is where things got weird. Within a few weeks, someone broke into my new car, and helped themselves to the Clarion, and its carefully hidden control box. My parents were on vacation, and the car was in the garage. Whoever it was had to know I had bought the car, and had installed my stereo. Nonetheless, they had basically done me a favour. So all I had to do was install the best Alpine I could get my hands on, and I'd be set. So, in went the brand new 7939. Marvelous unit! Great features, and sounded excellent. But for some reason, the tuner didn't seem to sound quite as good. But it had been a month, so I figured I was simply losing my mind.
The bottom line is that different brands and models excel at different
things. In those days, the Alpine's CD section sounded great, but the tuner
wasn't anywhere near as good as the Clarion's was.
Picking a head unit isn't really all that easy, but the selection of great sounding units in those days was awfully limited. The Pioneer DEX-M88, the Alpine 7909 and 7939 and then the Clarion 9255 were about the whole thing really. Many serious competitors are using external D/A converters and anti-jitter devices. These external units are not usually intended for the car audio environment, and will involve some custom circuit construction and interfacing. Apogee, Audio Alchemy and others make such units. They do make a difference, but also cost a great deal (well over a grand or two). It is well beyond the scope of this page to discuss those. If you are interested, you will likely need the support of a pro shop to help you anyhow.
So, what do you do about all these choices? You are going to have to do some careful research. I have found out a great deal from the judging I have done.
Many summers ago (1995), I was judging a show at Acoustic Concepts in Brantford, Ontario. One of the tests performed on the system involves checking for different forms of system noise. I was using the new (then) IASCA CD (release 3). It contains a track with no information. This represents the lowest possible level that your CD can produce. Hopefully it is a constant absolute 0 volts over the entire track. I turn the system volume all the way up, and listen for noise. I also start the car, and rev the engine, to check for installation related noise. Points are deducted for any noise I find: hissing, whining, clicking, etc.
Several years ago when I was new to the car audio scene, someone tried to tell me that Alpine head units produced an audible tracking sound. This person, Dave Olivera and I both listened to my system, and found it was no longer present in the model I owned (7980 at the time). We were both pleased. But this problem has re-occurred. I listened to two different Pioneer CD players, and both had an audible tracking noise while playing 0-bits and full volume. I also noticed an older Eclipse head unit doing the same thing.
Please know I am not trashing any manufacturers product. I respect every single company that takes the time to design their own car audio products (read: Some of them buy 'em somewhere else and put their names on them.) I also have a great deal of appreciation for budget limitations. So there are limits to how much we can spend on the audio system in our cars. BUT, I simply want people to make the best choices possible when picking equipment.
Todays head units are jammed full of features and processing. Equalization, delays and so forth all make the head unit purchase that much more difficult.