How can Time Alignment possibly work?

[audioholic 5,000+ posts]

 

[hoss 5,000+ posts]

Your ears detect distance in much the same way your eyes perceive depth. Have you ever noticed when you hear a sound coming from a certain direction and want to get a better feel for where it is, you turn your ear toward that sound? You can gauge distance by the difference in time it takes for the sound to go from the ear you pointed towards the sound to the ear you pointed away from the sound. Like you said, it's not extremely accurate, but it's something.
This is a big factor with your car stereo. Since you have one speaker on each side of your head, and the sound reaching your ears at different times, that causes your stereo image to be skewed, which is where TA comes in.

exactly, thats why i threw the disclaimer word in parenthesis in my reply //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

its not very accurate, but you can get a vague idea of teh discrepency. and with time alignment, you can fool your ear into thinking the sound is slightly further away than it really is.

you can kind of think of time alignment like corrective eye glasses for your ears. it is something that tricks you into thinking the sound is originating closer or further away than it really is.

 

[jmanpc 5,000+ posts]

exactly, thats why i threw the disclaimer word in parenthesis in my reply //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
its not very accurate, but you can get a vague idea of teh discrepency. and with time alignment, you can fool your ear into thinking the sound is slightly further away than it really is.

you can kind of think of time alignment like corrective eye glasses for your ears. it is something that tricks you into thinking the sound is originating closer or further away than it really is.

precisely. we tag teamed that bish like Supa's mom.

 

[atsaubrey 10+ year member]

Does T/A actually delay signals?

 

[newusername 10+ year member]

We have to be very careful about the words we use. For example, someone said that time alignment makes the sound seem slightly further away than it really is.

What we actually mean is that the image is shifted along the horizontal (X) axis (ie. left or right). The sound is not shifted forward or rearward (along the Z axis), nor is it shifted upward or downward (the vertical or Y axis).

Yes, T/A really works, and yes your brain (not your ears) can tell the difference in only a few m/s of delay.

However, the car environment is far more restrictive with respect to IID and HRTF issues, meaning the car's shaping of frequency response is far more detrimental to sonics than the car's effect on arrival times.

 

[newusername 10+ year member]

How can time alignment possibly work?

Put simply, we're playing back a stereo recording on a stereo system. The way the mind resolves sound is conducive to vector summation of 2 channels containing arrival time and SPL information. Unfortunately, our mind will not receive the correct vectors if the channels in the playback system add additional arrival time and SPL information; accordingly, we use T/A to minimize the differences in the playback system's arrival time (with respect to its 2 channels), and EQ's or a variety of physical treatments to minimize the differences in the playback system's (again, with respect to each channel).

Now the obvious caveat here is that good stereo in a vehicle requires the ability to minimize these differences, which is basically impossible for more than one seat. So we now must work on better capturing the wavefront and replaying it through other multi-channel systems.

 

[James Bang 5,000+ posts]

We have to be very careful about the words we use. For example, someone said that time alignment makes the sound seem slightly further away than it really is.
What we actually mean is that the image is shifted along the horizontal (X) axis (ie. left or right). The sound is not shifted forward or rearward (along the Z axis), nor is it shifted upward or downward (the vertical or Y axis).

Yes, T/A really works, and yes your brain (not your ears) can tell the difference in only a few m/s of delay.

However, the car environment is far more restrictive with respect to IID and HRTF issues, meaning the car's shaping of frequency response is far more detrimental to sonics than the car's effect on arrival times.

I delay my mids and highs relative to each other to raise the stage. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[newusername 10+ year member]

edit: Nevermind.

 

[Crodski 10+ year member]

//content.invisioncic.com/y282845/emoticons/redface.gif.62fdbfe1a101588a808c4cff71bcb942.gif

 

[ngsm13 5,000+ posts]

lulz...

nG

 

[req 5,000+ posts]

just get your ipod, turn it up loud.

put both speakers equadistant from your head about six inches away on each side facing your ears.

now move one like 12" away on one side, and keep the other in the same spot. the sound should no longer sound like its in the middle. it should be pulled toward the speaker that is closer to your head.

this is what time correction does, but instead of physically moving the speaker - it sends the data to it at a later point in time - simulating the distance over time rather than over space.

i didnt read your post, nor did i read anyone elses posts. your welcome.

wow, that rock picture from /b/ is funnay.

 

[Megalomaniac 5,000+ posts]

Know your roll

 

[PaulD 10+ year member]

And a useless post from you unless you care to point out all the "misinfo" here. Just keep your mouth shut if you don't have anything to back up what you're saying.

Sorry, I don't come in here very often - so first time I have reread this thread since my initial response. I can tell you for fact that even my old tin ears can hear a .5 ms delay, I tried it on the H701. RC used to call it time MISalignment because so many people did not understand what they were doing with it. As stated above it can be done elecronically with time delay or mechanically by speaker placement. If you look at expensive home speakers from the side, many of them have staggered speakers - they are lining up the speakers so the back of the cones are lined so the tweets will be almost half way back to line up with the woofer. In the car, we often have to place speakers will they will fit. If you want to minimize use of T/A, then find spots where the path length differences (PLD's) are minimized.

The best explanation of T/A I have heard I think was from wolfie. He used the bead analogy. Think of streching out a sting with beads on every other spot and the other spots are empty from say the left and right mid. The beads are waves at full strength, the empty spots are the places where the freq is at a 0 point. Time alignment is just used to align the beads so that the beads and empty spots are in "sync" at the ear. Following this example, you can easily see the problem with T/A. The space between the beads is analogous to the frequency, if you start changing the frequency the beads will go in and out of sync.

I guess I have rambled on enough and probably confused the hell out of most everyone.

 

[eharri3 10+ year member]

Just picked up a Pioneer Premier deh 980BT with time alightment and 16 band EQ (not channel independent though.) I haven't even really started to mess with the manual setting very much yet but just switching between the factory default time alignment setting for the driver's position, the generic setting for both front seat positions, and t/a disabled makes a huge difference. My setup is 2 way Hertz 165 front components getting 140 watts apiece from a bridged 4 channel, Infinity reference rear fill off the head unit, and 10 inch pioneer premier sub against the back wall of my truck's cab.

Goes from getting alot of very directional information from the speakers if time alignment is disabled, to a very intimate, narrow soundstage right in front of the steering wheel (don't like so much) when the driver's seat position is chosen, to having a wider soundstage centered in the middle of the windshield when both front seats are selected (my preference). My speakers have almost disappeared. Call it a crutch or a bandaid if you will, I'll never have a head unit without it. And I don't see how anyone who's ever actually tried it and used it properly doesn't think it makes a difference. I drive a pickup with a high seating position, I'd rather do this than have my front stage at my ankles.