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A Question About Time Alignment

I was reading a review of the Wilson Alex V on Stereophile recently. (Published just in time. I’m thinking about picking up a pair. Maybe a couple for the bedroom, too.) And it raised a long-standing question of mine, one that I hope the wiser minds on this site can answer. 
 

Wilson’s big selling point is aligning the different frequencies so they all reach your ear simultaneously. As I understand it, that’s why they have minute adjustments among the various drivers. The woofers put out bass notes that move slowly thanks to their long sound waves while the tweeters are playing faster moving, high frequency notes with short waves. Wilson lets you make adjustments so that they all arrive at the ear at once. 
 

It seems to me, however, that live music isn’t time aligned. Suppose I’m playing the piano and you’re sitting across the room. When I stretch out my left hand to hit the low notes, those notes travel along the same long, slow wavelengths as the notes from Wilson’s woofers. Similarly, the treble notes I play with my right hand move quickly through the short wavelengths. The notes from the piano are naturally out of alignment. If Wilson’s goal is to achieve a lifelike sound, aligning the frequencies doesn’t seem like the way to do it. 
 

Wilson has been selling lots of zillion dollar speakers for lots of years and people continue to gobble ‘em up. Something must be wrong with my line of reasoning. Would someone please point out where I’ve gone wrong? Nicely?

paul6001

Showing 1 response by jeffrey75

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jeffrey75
111 posts
 

I tried to read every post here but too many have confused light waves with sound waves, light travels as a electromagnetic wave composed of photons, all electromagnetic waves travel at the same speed which is the speed of light.

Sound waves are a vibration, does not contain any photons, the vibration alternately compresses and decompresses the air particles next to it, creating a wave that is composed of compressions and refractions. Sound cannot therefore travel through space where there are no particles to create a sound wave.

Everything affects sound when it is in the air there is no free ride it is not a electromagnetic wave...

I copied and pasted the following for those of you in need of quick refresher:

You can calculate the wavelengths of audible sound in air. Audible sounds in air have frequencies that range from roughly 20 Hz to 20 kHz. Not surprisingly, the wavelengths of audible sounds also vary widely. Assuming a speed of sound of 340 m/s,

For 20 Hz sound in air: λ=vf=340m/s20Hz=17m

 

For 20 kHz sound in air: λ=vf=340m/s20,000Hz=0.017m=1.7cm

 

This calculation shows that wavelengths of sounds in air are distinctly human sized. The wavelengths range from roughly the diameter of a dime (for the highest frequencies) to roughly the length of a city bus (for the lowest frequencies). For comparison, the wavelengths of visible light are all far smaller than the thickness of a single human hair and have a very narrow range (from roughly 400 to 700 nm).

 

  1. The shorter wavelength sound has the higher frequency. Both sounds travel at the same speed.
  2. When the sound goes from cooler to warmer air, it's speed increases (because sound travels faster in warmer air). The frequency doesn’t change (unless the source changes). Since speed increases and frequency is unchanged, the wavelength must increase. Increasing the number for wave speed in the equation λ=v/f
  1. without changing the number for frequency will lead to a bigger value for wavelength.

 

 

 

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