Quote:
Originally Posted by GregV
(Post 403648)
So for us non audio engineers who have no idea what that video is showing us, these settings will make the factory stereo sound better?
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An "ideal" audio system is one that can reproduce the original recording
exactly as it was recorded. This means it produces a flat frequency response, so the speakers are
actually producing measurably even response across the 20-20000Hz range in the environment. Most albums are mastered in a recording studio for perfect balance and sound quality, but not many people have a studio, or a dedicated listening room that has perfect acoustics and sound reproduction. Most listeners don't want a perfectly flat response, they want the music to have a little color, as the OP stated, warm, rich sound isn't perfectly flat.
Cars are high on the list of terrible listening environments. Aside from engine and road noise, cars have awful acoustics (control of how the sound moves around the space) lots of hard surfaces for reflection (such as glass) and very poor listener positioning (sitting off-center). The speaker positions are also screwy, with the mid-woofers and tweeters all being in different locations, and EVERY one being a different distance from the listener. What you normally end up with, is just
sound mixed with
noise. A lot of the "noise" is the sound you want to hear, just not exactly when/how you should be hearing it. You may be able to hear the music clearly, but probably not at high volume levels for very long, because it causes psychological listener fatigue. So you switch tracks, listen to another artist, or just turn it down.
By using the EQ, you have some control to achieve a flatter frequency response. This is always a goal of any audiophile (as a starting point). A flat frequency response could be very difficult to achieve in a car, especially with a typical OEM system. The speakers themselves probably don't produce a flat response, let alone in a screwy acoustic environment that affects frequencies even more. What you end up with is a system that has big spikes and dips from an audio analysis as shown above. Even if the processor says it's using a "flat" EQ curve, it's referring to the
source signal, not the environment and the actual resulting sound quality. (Imagine listening to a perfectly adjusted high end stereo system through a cardboard tube on your ear. Sounds like crap, right?)
White noise and pink noise are both randomly generated "noise" that covers the entire spectrum from 20-20000Hz. This noise is used by analysis tools to measure what's being produced by a system. White noise uses even energy across the spectrum, whereas pink noise lowers the energy at higher frequencies (reduces 3dB per octave). Our ears hear sound logarithmically (on a curve) and are more sensitive to mid-range and high frequencies, so to the ear, a 100Hz bass tone at 70dB wouldn't
sound as loud as a 4000Hz squeal tone at 70dB. White noise would sound level and even to a microphone, but pink noise would sound level and even to a human ear. With pink noise, that 4000Hz range would be about 15dB quieter, and it would sound about the same level as the 100Hz tone to the human ear.
By measuring what the stock system is actually doing (not just what it says onscreen) you can
see what your ears are hearing, and you can make adjustments to fix some of the issues mentioned above. Hopefully for most, this does the trick and you've just improved your sound and saved a bundle on a bunch of audio stuff you don't need.
However, if you still need more, there's two key points to consider beyond amps and speakers if you're looking to make improvements. 1- sound deadening- (improving acoustic control of the environment). 2- time alignment- Time alignment is a critical step to make the sound appear accurate to the driver's position. This adjusts when the signals are sent to each speaker by adding a slight delay (sometimes only a few milliseconds) to the speakers closest to you. The goal is to get the sound from each speaker to reach your ears at the same time, with proper EQ and volume level. Many DSPs (digital signal processor) and some high end head units can use a calibrated microphone that will make this time adjustment automatically, and can also EQ each speaker individually in ways inaccessible to the user. What you end up with is a system that sounds clean, clear and accurate to your ears, like you're watching the performance happen right in front of you. Hardcore car audiophiles will also get into custom speaker placement and enclosures, but that's another topic.
