Laying the Foundation, Part 3
Heads up!Welcome to this article from the Crutchfield archives. Have fun reading it, but be aware that the information may be outdated and links may be broken.
Now that the receiver's in and the iPod is hooked up (see my first two posts for the full scoop), what about equalization and other signal processing for the system?
While I wait to deploy what is likely the ultimate in customizable equalization for a car - Alpine's IMPRINTTM sound tuning system -- the CDA-9887 by itself provides solid parametric and graphic equalizer options. Parametric EQs are always welcome audiophile tools, as they allow precise adjustment of specific tones with minimal effect on surrounding frequencies. I use ‘em in the studio to, for example, filter out line noise from a guitar amp without changing the tonal character of the guitar. They're also great for tightening up a "boomy" sound, or even to add resonance to a brittle sound. Piano's left-hand bass line buried in the mix? A little parametric dab'll do ya.
The built-in graphic EQ features 10 factory-assigned and six user-programmable presets. The ones from Alpine are named by musical genre, and I had fun scrolling through all of them. That kind of thing is not really my bag; but it was instructive to hear the various colorizations of the sound, as they suggested possible approaches we could take with our mixes. At the very least, I have to give Alpine props for the naming of the presets; they certainly seem apt. As to the user-configurable presets, my buddy Jeff, a car audio/video buyer here and a savvy listener, took it upon himself to subtly sculpt out some upper midrange resonance, elevate the mid-bass and add a touch of top-end sparkle. Voilà, another flavor. Too bad this thing won't allow the user to title their presets or I'd name it after him.
My favorite signal processing feature from Alpine -- and a true hi-fidelity enhancement -- has to be Time Correction. At home, the listener can painstakingly optimize speaker placement, plop herself down in the room's "sweet spot," center close her eyes and hear a musical ensemble magically and accurately align itself in front of her. Vocalist in the center, drummer directly behind, guitar to the left, bass to the right, horns in the back and to the right, etc.
(Image courtesy of Alpine Electronics of America)
In the car, the speakers can only be placed in designated locations determined by auto engineers as low-priority, low-cost considerations. The listener - unless he is an 8-year-old child or Labrador retriever commandeering the middle of the rear seat -- has to sit at the extreme left or right directly in front of a single speaker. To address this problem, Time Correction delays the signal to the speaker closest to the listener, fooling the brain into thinking the sound is traveling a greater distance - equal to the distance of the farthest speaker.
To set it up, all you need is a tape measure or Jeff's incredible ability to visually gauge distances to within an inch. Sit in your listening position and measure the distances to all the speakers. Subtract the distances to all but the farthest speaker from the farthest distance, divide by the speed of sound at 20°C (it's in the manual); the resultant times are the time correction values for the various speakers in your car. And what's even more amazing is that you can store all of those values in memory, so everyone in the car can be in the sweet spot. Not at the same time, of course; now that would be some seriously cutting-edge technology.
So, in terms of sound quality, it seems that our Alpine stereo and iPod nano combination is doing the trick. I should probably even mention Alpine's cool Blackout Mode feature, which you can set to cut energy from the lights and display after 5 seconds of non-use of the stereo. Meaning, the machine winks out when you're not touching it, thereby diverting power to the audio section for even better sound.
Now what's the next step? Speaker replacement, I'm thinking. I have provisions for 6-1/2" component speakers in the front doors and 6-1/2" full-range speakers for the rear doors. We'll put those in and see how they sound, powered by the 18 watts RMS that the CDA-9887 cranks out into four speakers.
Thoughts? Comments? Suggestions? Let's hear 'em.
Thanks for reading, and don't forget to get your groove on. [:)]
Read the entire Building a Mobile Listening Lab series:
- Laying the Foundation, Part 1
- Laying the Foundation, Part 2
- Laying the Foundation, Part 3
- Dynamat installation and pre-wiring for amplifiers
- Installing the front door speakers
- Video: factory vs. aftermarket speakers
- Rear speakers, amplifier, and subwoofer
- Report on the Yukon system's performance
- The ultimate in system tuning
- Video: Alpine's IMPRINT signal processing in action