DECWARE Car Audio - time alignment schematic

HOW TO WIRE YOR 2 CHANNEL CAR STEREO WITH
TIME ALIGNMENT!

COMMENTS FROM STEVE

I get several emails each day asking basically the same question; "What should I do, and how should I hook up what I've got." Most of the time the equipment listed in the e-mail is too long. The hypothetical questions that always follow often don't leave me any options other than picking the lesser of two evils. In fact I'd like to reply to most of them by saying “take everything on your list back to the store and lets start over!”

There are many secrets in audio that remain secrets not because someone doesn't want you to find out, but rather because you couldn't accept the answers. For example, BIGGER is NOT better in audio most of the time. Especially true in cars.

Anyway, here is a “ninja trick” to make a 2 channel car stereo with front and rear speakers sound twice as good without purchasing any additional crap. It's called Time alignment and it creates better imaging by making the sound come out of the speakers farthest away from you FIRST and the sound come out of the speakers nearest to you LAST.

INTRODUCTION

One of the reasons car audio sounds like crap when compared to a high-end listening room is because you sit directly by the left front speaker. If you did that in your listening room, the results would not be all that unlike the car stereo.
The side effect of this dilemma is far more noticeable than what brand of speaker your using or how much power it handles. Remember, the whole idea of STEREO ie. 2 channel audio is IMAGING. That's what places instruments in the imaginary space between your speakers. For example, the Vocals may come out of the middle, the bass off to the left and guitar off to the right. GOOD stereo systems take this one step further and also image from FRONT to BACK. I don't mean between the front and rear speakers in a car, I mean your front speakers have depth. The sound images between the speakers and also images behind the speakers.
PROBLEM is that in a car the image that would normally come from the center will come from whatever side your sitting on. The driver hears the image come from the left speaker and the passenger hears the image coming from only the right speaker. If you sit in the middle of the car the image comes from the middle – unless you move your head to the left in which case you'll hear the image SHIFT over to the left speaker. Very annoying.

TIME ALIGNMENT

Back when I was selling Car Audio, there were only three systems on the planet that could time-align the output of each speaker so that the sound reached the driver's ear at the same time. These three systems were computers sold by Alpine, Rockford Fosgate, and Clarion. The cost was thousands of dollars, but they worked rather well.
Once you listen to a time-aligned system you realize that it doesn't matter what kind of gear you had installed in your car, it will never sound as good as one of those. They work by using a calibrated microphone during a set up procedure where bursts of sound come from each speaker and measured. What is being measured is the time it takes the sound from each speaker to hit the microphone. Once this data is in tact, the computer creates delays for each channel so that the sound from ALL speakers arrives at the microphone at the same time. When this happens, the music quits SHIFTING around when you move inside the car, and it IMAGES like it's suppose to, not to mention just SOUNDS better.

I'm going to show you how to use the typical 15 degree phase shift that occurs when you series two speakers together to create the same result. All that is going to be required is changing how your speakers are wired to your two channel head unit, or amplifier.

HOME GROWN TIME ALIGNMENT

to DRASTICALLY improve the sound of any car stereo regardless of brand or price. It favors a simple 4 speaker system (sub-woofer optional) run from two channels.
In a normally wired car stereo, you hear sound coming directly from the speakers and only the speakers closest to you. This is the reason for a fader control. The fader control is like a bandage to try to balance a system incapable of controlling the sound energy in a time domain fashion.

Move your head to the right a little and the sound (image) flies over to the right speaker. Move your head back a little and the sound flies over to the rear of the car. Even on 5000.00 speakers with miracle wire etc. Time alignment solves this problem and makes it possible to hear sound coming from each of the four speakers at all times regardless of where your head is. It also completely opens up and stops fatiguing/compressing the ears. Details in the music come from space in the car and never from the exact speaker locations - as it should be.

To understand time alignment, you need to understand phase, and phasing relationships between various parts in the audio circuit. Absolute phase means that when the audio signal goes positive, the speaker cone pushes into the listening space. Reversing the speaker wires reverse the phase, and the phase angle becomes 180 degrees rather than absolute zero. If left in reverse phase, the sound will be delayed by 1/2 cycle. This delay can be converted to inches based on frequency and effects the arrival times of sound to the ear. The ear perceives this as depth or distance from the sound emitting object.

It is safe to say that how you wire a group of speakers and the crossovers you use can effect the phasing of each speaker in that system. Putting every speaker in absolute phase, as all manufactures suggest, will not work unless you sit in the exact center of the speakers. Add to this the unpredictability factor of reflections from glass and so on, and even that will not work.
The idea is to have the sound come out of the speaker farthest away first, and the sound coming out the speaker closest to you, last. The result is the illusion of sitting in the center.

You will find that there is more bass, more detail, more everything when this has been achieved. So how do you do it? Odds are you'll have to get rid of something you purchased, because this only works with a two channel amplifier. This means that if you have a sub-woofer, the most amplifiers you can have and do this, is two. One for the bass and one for everything else.

You will not have a fader. You will not need one, or ever feel the desire to have one when you hear this. Your sub-woofer will be run on the rear channel output of your head-unit. Everything else will be run off the front channels of the head unit. This arrangement allows the sub-woofer to be turned up or down, eliminating the need to use your bass control and muddy up the music.

A high power head unit will power a 4 speaker system (6 if tweeters are added) to a surprising loudness, usually enough to eliminate the need for an amplifier. This is because the impedance of the speaker circuit works differently than before and drastically lowers distortion at high output levels.

The diagram to follow is the magic wiring scheme that time aligns your speakers so well the only thing close is the computer alignments. It takes advantage of the natural phase shifts of around 15 degrees between drivers when two drivers are wired in series. It must be followed exactly with no exceptions. No passive crossovers can be used on any of the drivers other than the tweeters if used. Sub-woofers should be actively crossed over somewhere between 50 and 90 Hz if used.

Even a factory stereo can be rewired like this in most cases. The impedance of the drivers (they're usually 4 ohms anyway) aren't critical.

The COMPLETE WIRING DIAGRAM can be downloaded online for $19.95

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