A Question About Time Alignment

Please don’t be rude and call science BS because you don’t believe in it. These are measurable results that I can produce which you can hear and isn’t BS in any way.  Your example with thunder and lightening is a great practical high school example. Thunder is caused by the lightening strike by expanding air around the bolt. Light travels at the speed of 186,291 miles per second and sound travels at 1,088 feet per second (depending on the air temp) so if you count the number of seconds from when you see the lightening bolt to the sound you hear and divide by 5 that is roughly how many miles the strike is from you. If there is no time between the strike and the sound find cover! Science my save your life in a thunderstorm and it can help reproduce the best recording reproduction you will ever hear. I learned a lot from this site and feel it is important to respect all views on the forum. If you have measurable scientific data that I’m full of BS I’d love to research it but I’m afraid the entire study of Physics and my ears disagree with you. 
 

Thanks,

Steve

@hifidream Steve, your post was great except for the velocity being a function of the frequency.

I can see how one might think that the velocity is a function of frquency as t links like this show v = freg * wavelength

let’s just round off the speed to 1 foot/millisecond.
And at a 1000 feet away the 1Hz takes a second to travel it.
what amount of time does 20Hz take to arrive?
And what amount of time does 20kHz take to arrive?

I have no doubt you MiniDSP sound good, and I suspect that the tweeter to woofer delays are on the order or inches or fractions of a millisecond.

if the speed was a function of frequency the the lightening crack would sound like a descending chirp from 20KHz down to 20Hz.
But it doesn’t, we see the lightening and we hear the crack a bit later. When it is so close that it is almost simultaneous our we also tend to crap our britches.

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: $\lambda =\frac{v}{f}=\frac{340m/s}{20Hz}=17m$

For 20 kHz sound in air: $\lambda =\frac{v}{f}=\frac{340m/s}{20,000Hz}=0.017m=1.7cm$

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).

Time delay is something that your brain uses to locate sounds in space. We are extremely sensitive to it. We can perceive fractions of a second. The reason we know that a sound comes from right center is because our ears and brain are sensitive enough to detect the difference in the timing of the sound hitting our right ear and then traveling across our face to our left ear. If time alignment didn’t matter than we couldn’t locate sound in space. The reason we aren’t completely fooled that we are listening to a live performance is because our left ears are picking up what the right speaker is playing and the right ear is picking up what the left speaker is playing. That is why highly directional speakers can often make a spooky 3-D image if set up and corrected properly but that sweet spot is extremely small (like move your head fractions of an inch small). That is why time alignment and room correction are both important to mitigate room nulls to get the best image possible. There is a ton of disinformation here and I spent years sifting through the chaff to create a system based on factual measurable scientific results. If anyone is struggling to figure out why things just don’t quite sound right the answer is probably in this realm and it is often overlooked because time alignment and room correction are perceived as difficult to do and frankly not many people have heard a system set up correctly employing these techniques. This forum is about sharing ideas. People put great weight into small physical changes in their systems. It would behoove them to respect the power time alignment and room correction can truly make as well. Perhaps a user will find this insightful, easy to understand, and seek to better their system because of it. That’s why I’m still posting from time to time even if I get trolled by someone who doesn’t believe in science. 
 

Thanks,

Steve

Steve,

@hifidream You should read up on Head Related Transfer Function research.  It's a lot more than timing.

Having said that, I've heard speakers with great, near perfect impulse responses and they did not by themselves move me.