Wanted, A crack team of monkey's!

[boombexus]

Hey guy's!
I need your crack team of monkey's working on this problem for me!
I actually got it figured out but I am interested to find out what conclusions you came to.

The subject is, "Adjusting the Time Correction."

This is a feature that my car CD player has. It has numbed my mind for the last day!

Below, I will write down the "exact" directions from the owners manual.

See if you can get to the same conclusion as me. I had some challenges with this and I would really like to see how all of you figure it out.

Here is the information that you will need to figure this out. These are the distances from each speaker to my listening position in the car.

Subwoofer: 80 inches (2.03 meters)
Front left speaker: 43 inches (1.09 meters)
Front right speaker: 56 inches (1.42 meters)
Rear left speaker: 33 inches (.84 meters)
Rear right speaker: 51 inches (1.30 meters)

Conversion from inches to meters, divide by 39.37

Directions: Adjusting the Time Correction.

Time Correction:
The distance between the listener and the speakers in a car vary widely due to the special conditions of the mobile environment. This difference in the distances from the speakers to the listener creates a shift in the sounds image and frequency characteristics. This is caused by the time delay between the sound reaching the listener's right versus the left ear.
To correct this, the CDA-7969 is able to delay the audio signal to the speakers closest to the listener. This effectively creates a perception of increased distance for those speakers. The listener can be placed at an equal distance between the left and right speakers for optimum staging.
The adjustment will be made for each speaker in a step of 0.1 mS.

Example 1. Listening Position: Front Left Seat
Adjust the time correction level of the front left speaker to a high value tand the rear right to zero or a low value.

Here we calculate the time correction value for the front right tweeter.
Conditions: (here you will insert my figures given above, but for ease of typing and to see how their figures work I will include theirs instead of mine.)
Farthest Speaker-listening position: 2.25 m (88-9/16")
Front right tweeter-listening position: 0.5 m (19 11/16")
Calculation: L=2.25 m - 0.5 m = 1.75 m (68 7/8")
Time correction = 1.75 divided by 343* x 1000 = 5.1 (ms)
*Speed of sound: 343 meters a second (765 mph) at 20 degrees Celcius.

In other words, giving the front right tweeter a time correction value of 5.1 ms makes it seem as if the distance to the front right tweeter is the same as the distance to the farthest speaker.
The sound is not balanced because the distance between the listening position and the various speakers is different. The difference in distance between the front right speaker and the rear left speaker is 1.75 m (68 7/8")

Time correction eliminates the differences in the time required for the sound to reach the listening position. The time of the front right speaker is corrected by 5.1 ms so that its sound reaches the listening position at the same time as the sound of other speakers.

Get those monkey's on it and tell me what figures you came up with!
I will post mine later on and then explain what actually happened when this was put into practice.

Peace,

Boom

 

[1X83Z]

Subwoofer to rear-left
Difference = 1.19 metres.
Time correction value = 3.4693.

Subwoofer to rear-right
Difference = 0.73 metres.
Time correction value = 2.1282.

Subwoofer to front-right
Difference = 0.61 metres.
Time correction value = 1.6353.

Subwoofer to front-left
Difference = 0.94 metres.
Time correction value = 2.5201.

 

[boombexus]

Let's get some more responses.

 

[Dudebusta]

i have no farkn idea what you are on about my crack smoking friend.

 

[Gil]

Does it really matter that much?
Unless you're getting a doppler effect, leave the setting alone.
Besides, you'd have to change the setting if you wanted to effect the "gangter lean" while driving.

 

[Duke]

And never mind the fact that it would sound like absolute garbage for someone sitting in, say, the right rear seat.

It's a cool concept but in the confines of a car, I think it's a totally moot point. Now, if you were trying to tune the acoustics for a concert hall...

 

[boombexus]

Originally posted by Gil
you'd have to change the setting if you wanted to effect the "gangster lean" while driving.

And never mind the fact that it would sound like absolute garbage for someone sitting in, say, the right rear seat.

Your right neon_duke! But I don't care how it would sound to that person, they didn't pay for the stereo system.



I actually thought that you two would have taken this problem on!

 

[Duke]

Well, I would have, but it's Friday afternoon...

And, point taken about the owner of the stereo!

 

[Gil]

Originally posted by neon_duke
Well, I would have, but it's Friday afternoon...

And, point taken about the owner of the stereo!

I did tackle the question. Quote: "...leave the settings alone" unquote.
As I am fond of saying, "For every high tech problem there is a low tech solution."

sorry: trying to keep my sense of humor in the face of adversity.

 

[boombexus]

Hey Gentlemen!

The point of this feature is to set the sound stage in your vehicle. It is quite the unique feature! I now have it properly set up and it sounds that if the band is playing right there on the hood of your car! It's amazing!

The reason that I posted this thread is to find out if others,(following the directions stated above) came to the same conclusion as I did. I followed the directions to the "Tee" and when I put this into practice and listened to it, it didn't sound correct.
I want to see if the problem was with me,(probably) or with the hard to follow instructions.

 

[Hooligan]

Originally posted by boombexus
The point of this feature is to set the sound stage in your vehicle. It is quite the unique feature! I now have it properly set up and it sounds that if the band is playing right there on the hood of your car! It's amazing!

Unless your front tweeters and mains are within 1 foot of each other, you're probably not going to be far enough away for the sound to cohere properly. Granted, they may be time-aligned (if you can have separate settings for the tweeter and main drivers), but the phase distortion alone sets things off. Your rears and sub(s) should be okay, though.

Of course, this *is* just a car we're talking about. Unless B&W starts making "in-car" Nautilus, I'll stick with whatever sounds good in the store. It's a messy, unpredictable, and (if you drive a 1979 Ford Wagon) amourphous environment, I'd hate to be the acoustician for certain people's vehicle. Now if someone even *mentions* "toe-in"....


And to M5Power: You need busier Fridays. You were just too quick on the spot with the answer.

 

[1X83Z]

Originally posted by Hooligan

And to M5Power: You need busier Fridays. You were just too quick on the spot with the answer.

It was 2:45 AM and Dan Abrams was just about to start.

Am I the only one who answered?

 

[SaleenASL]

i dont have a crack team of monkeys, but i do have a team of crack monkeys. they said leave it how it was, the inside of your car isnt big enough to make that much of a difference.

 

[boombexus]

Originally posted by Hooligan


Unless your front tweeters and mains are within 1 foot of each other, you're probably not going to be far enough away for the sound to cohere properly. Granted, they may be time-aligned (if you can have separate settings for the tweeter and main drivers), but the phase distortion alone sets things off. Your rears and sub(s) should be okay, though.

Look at the distances that I wrote down above. The speaker placement is just fine. The mid-range and tweeters are a co-axial set up, that have been placed in kick panels down by my feet. They are angled up twords me, there fore the best possible imaging is achieved.
The "rear" speakers are actually my mid-bass drivers located in the front door stock locations.
It's hard to explain how effective this time correction setting is! You would have to hear it, but it does create an ubelievably real sound stage.

 

[boombexus]

Originally posted by SaleenASL
i dont have a crack team of monkeys, but i do have a team of crack monkeys. they said leave it how it was, the inside of your car isnt big enough to make that much of a difference.

If you ever get a chance, go to a local car stereo competition. There are IASCA sanctioned sound events all around the country (US) where the absoulute best of the best compete.
Sit and listen to someones stereo system, and find out what a car stereo system that has been set up by professionals, sounds. You might also have to opportunity to see some companies demo vehicles, these would be a great opportunity for you to see how car stereo should be done!

The inside of a car's interior sure isn't big but there is an amazing amount of things that you can do to make it rival the best of home stereo systems. You'll be surprised!

Peace,

Boom

 

[boombexus]

Why would you guy's recomend to "leave it alone?"

If you had a function on your car that made it perform better, wouldn't you use it?

 

[SaleenASL]

sure if you tune it right, it would perform better. but the increase in performance is probably pretty small. i wouldnt mess with it unless you enjoy tinkering with your stereo a lot, or if u are a total audiophile.

 

[boombexus]

Originally posted by SaleenASL
sure if you tune it right, it would perform better. but the increase in performance is probably pretty small. i wouldnt mess with it unless you enjoy tinkering with your stereo a lot, or if u are a total audiophile.

Oh yeah!

I love car audio!
As I said before, I did get it working properly but it took some trial and error. It sounds absoululy amazing! It really does make a huge difference.
But, I wanted to ask you guy's what conclusions on the time correction "values" you had come to. When I followed all the instructions mentioned above, the sound was biased to the right, where it should have been centered!

I needed to know if I was the one that was wrong or if the instructions were wrong.

 

[Gil]

Originally posted by boombexus
Why would you guy's recomend to "leave it alone?"

If you had a function on your car that made it perform better, wouldn't you use it?

I did the "important" math on this problem: 2 brain cells, 4-6 variables, and virtual math.

All that outstripped the available brain cells.

Then I immediately went to the "low tech" solution.

 

[boombexus]

, I read you Gil!

 

[Hooligan]

Originally posted by boombexus
It's hard to explain how effective this time correction setting is! You would have to hear it, but it does create an ubelievably real sound stage. [/B]

It's also hard to explain what real good audio sounds like. Believe me, it's not going to be in a car. Digital time alignment has been tried for more than a decade in the home audio (and pro audio) industry. It just doesn't work as well as properly-designed equipment and proper location.

Your setup might be as good as it gets inside the confines of a car, but it's still a far cry from a half-decent home audio setup. I guess the major contributor to my opinion is this: when I'm driving, the music stays in the background, the road comes first. :burnout: