DiyMobileAudio.com Car Stereo Forum banner

21 - 40 of 61 Posts

·
New CAJ Member!
Joined
·
437 Posts
Discussion Starter #21
Following suit...

I've pretty much decided to do just the front in the truck at this point anyway.

I saw a thread recently on how to set rear fill up on a DSP. I will be going that route when I set my car up. I'm using a DSP Pro on it.
 

·
Registered
Joined
·
2,613 Posts
well, i guess i'll do my best to remember what i said and repost it.

to anyone saying not to bother with rear fill, i highly suggest trying to find someone with a PROPER rear fill setup and taking a listen. little do many know, that some of the top scoring cars also use rear fill. it absolutely does not interfere with stereo imaging and also helps enlarge the soundstage if done right. that said, the twk isnt capable of doing proper rear fill
*LIKE*

Sent from my Pixel XL using Tapatalk
 

·
Moderator
Joined
·
18,516 Posts
it absolutely does not interfere with stereo imaging ... if done right.

that said, the twk isnt capable of doing proper rear fill
*channeling my inner Oscar here*

Actually, both of these statements are incorrect.

Differential rear fill will interfere with the imaging depending on the track. How it's set up plays a large role in this so in some cases the negative impact can be tolerable, but they're still present. For example, if you have music with hard panned information that can often be played dead in the center behind you which hurts the soundstage.

L + (L - R) + R + (R - L) = L + L - R + R + R - L = 2L - R + 2R - L = L + R

L+R is summed mono.

The "if done right" part makes things tricky. So, let's say you attenuate the signal enough to where the above doesn't really bother you. Now you've attenuated it so much that when it would provide the benefits we know of, they won't actually be audible. :rolleyes:

I've experienced this with a lot of my music since I like a lot of music that has hard panned information. It's just one of those things you have to understand and decide if the benefit (potential enhanced soundstage size) outweighs the negatives (soundstage size can collapse).




The twk88 can do differential rear fill. A friend of mine told me how to set it up. I did and can verify it works. :)




Edit: FWIW, I'm not seeing any posts in this thread having been moderated so it must be something with the site today.
 

·
Registered
Joined
·
18,420 Posts
*channeling my inner Oscar here*

Actually, both of these statements are incorrect.

Differential rear fill will interfere with the imaging depending on the track. How it's set up plays a large role in this so in some cases the negative impact can be tolerable, but they're still present. For example, if you have music with hard panned information that can often be played dead in the center behind you which hurts the soundstage.

L + (L - R) + R + (R - L) = L + L - R + R + R - L = 2L - R + 2R - L = L + R

L+R is summed mono.

The "if done right" part makes things tricky. So, let's say you attenuate the signal enough to where the above doesn't really bother you. Now you've attenuated it so much that when it would provide the benefits we know of, they won't actually be audible. :rolleyes:

I've experienced this with a lot of my music since I like a lot of music that has hard panned information. It's just one of those things you have to understand and decide if the benefit (potential enhanced soundstage size) outweighs the negatives (soundstage size can collapse).




The twk88 can do differential rear fill. A friend of mine told me how to set it up. I did and can verify it works. :)




Edit: FWIW, I'm not seeing any posts in this thread having been moderated so it must be something with the site today.
how exactly do you do it on the twk?
 

·
Registered
Joined
·
81 Posts
Why L-R instead of R-L?

Why is it that only the noncommon signals are wanted?
Why not only the shared frequencies?
Why not full range?

If we're trying to duplicate the ambient reverb (or whatever) of an actuyal venue, why not the full range signal?

Couldn't I just place my rear speakers on axis with each other and let that remove the common signals through cancellation?

Can resistors be used to achieve the wanted delay?

what about full range but with reversed polarity to cancel out the waves which reach the rear to create an anechoic(sp?) effetc?

What about speaker placement?
Factory in the rear deck facing up
2 speakers placed centraly on the rear deck facing up, angled forward, rearward? angled to the rear?
OR on the Cpillars forward upward or rearward?

Why the limited ban width at all...

Anyway, that will give me a bit better understanding.

I've been reading all the post i could find for days now... I think I might be more confused now than when I started.

Thanks for any help.
 

·
Registered
Joined
·
2,046 Posts
When using rear fill you want it to sound like reflected sound. Nothing else.
The huge delay is to make it sound like there is a large room behind you.
The L-R or vise versa is to remove any mono or center content. Using this content will pull your ears to the rear.
In the end what you are trying to achieve is the simulation of hearing reflections on a much larger room than a vehicle and all the little things we do to process the rear fill are to eliminate the rears from sounding solid, but instead washed out and being reflected to you from a distance.
Have you ever been to a concert?
If you have you'll here the direct sound of the band coming from in front of you but you'll also hear the room the band is performing in.
It comes in lower in volume. It's basically an echo but continuous and much faster.
It's this sound we try to achieve with rear fill. Not to sound like the band had speakers at the back of the room which is what non processed rear fill does.

Also why band limited and not full range. Reflected sound looses high end and low end content pretty quickly. High end content especially gets duller faster over distance. The more high end content you remove the further away the back wall of the fake room we are trying to create will appear.
 

·
Registered
Joined
·
18,420 Posts
Copy and pasted from another thread.. PS, you dont need to ask the same question in multiple threads ;)

Why L-R instead of R-L?

same thing



Why is it that only the noncommon signals are wanted?
Why not only the shared frequencies?
to create a sense of space


Why not full range?
If we're trying to duplicate the ambient reverb (or whatever) of an actuyal venue, why not the full range signal?

higher frequencies are easier to locate. lower frequencies arent needed as far as i know





Couldn't I just place my rear speakers on axis with each other and let that remove the common signals through cancellation?

thats not how sound/speakers work


Can resistors be used to achieve the wanted delay?

umm.. thats also not how that works



what about full range but with reversed polarity to cancel out the waves which reach the rear to create an anechoic(sp?) effetc?

That will also cause destructive cancellation with the front speakers. rear speakers with heavy delay will also cause cancellation with the front speakers, but not like this. they will just cause some comb filtering.


What about speaker placement?
Factory in the rear deck facing up
2 speakers placed centraly on the rear deck facing up, angled forward, rearward? angled to the rear?
OR on the Cpillars forward upward or rearward?

same as any speaker in a car.. ideally as deep and wide as possible



Why the limited ban width at all...
you asked that above

Anyway, that will give me a bit better understanding.

I've been reading all the post i could find for days now... I think I might be more confused now than when I started.

Thanks for any help.
hope that helps. someone correct me if im wrong
 

·
Banned
Joined
·
2,276 Posts
So funny how just a few months ago rear speakers was the devil.
Maybe I didn't have something right or just wasn't listening enough but I couldn't hear a difference with the MS-8 running rears with logic 7. But they where only low in the rear doors not far from my head.
 

·
Registered
Joined
·
122 Posts
Loved the space it added. Also helped set my stage deep. I could steer the stage to just in front of my car. Very weird to experience

Sent from my Pixel XL using Tapatalk
Ive been doing this too I have my rear fill mid range component(no tweeter) set from 70hz to 2000hz. I time aligned them to 18ms or so both sides and it sounds like its coming from the middle to front of the car. I like how it adds some depth also. Its pretty cool how you can steer it from the doors to the center and up the left or right side or keep it in the back center like its coming from the rear deck.
I also have them set to mono seemed to work best and they aren't super loud.

Whats a good cutoff point to set them? Ive been playing with 3500 and under.
Do you have rear tweeters? I disconnected mine.

Also, I have an Audi A4 sedan. No rear fill feels like something is missing. Even though its subtle its better in bigger cars I think. Id never do it in a coupe.
 

·
Registered
Joined
·
122 Posts
When using rear fill you want it to sound like reflected sound. Nothing else.
The huge delay is to make it sound like there is a large room behind you.
The L-R or vise versa is to remove any mono or center content. Using this content will pull your ears to the rear.
In the end what you are trying to achieve is the simulation of hearing reflections on a much larger room than a vehicle and all the little things we do to process the rear fill are to eliminate the rears from sounding solid, but instead washed out and being reflected to you from a distance.
Have you ever been to a concert?
If you have you'll here the direct sound of the band coming from in front of you but you'll also hear the room the band is performing in.
It comes in lower in volume. It's basically an echo but continuous and much faster.
It's this sound we try to achieve with rear fill. Not to sound like the band had speakers at the back of the room which is what non processed rear fill does.

Also why band limited and not full range. Reflected sound looses high end and low end content pretty quickly. High end content especially gets duller faster over distance. The more high end content you remove the further away the back wall of the fake room we are trying to create will appear.
Are you saying don't run the rear mids in mono?
What bandpass range would you set ?
 

·
Registered
Joined
·
18,420 Posts
Are you saying don't run the rear mids in mono?
What bandpass range would you set ?
No, you want l-r, the opposite of mono. And frequency range you gotta play with. You don't need extra midbass though

Sent from my VS988 using Tapatalk
 

·
Registered
Joined
·
122 Posts
No, you want l-r, the opposite of mono. And frequency range you gotta play with. You don't need extra midbass though

Sent from my VS988 using Tapatalk
I can change it on the fly and I seem to always go back to momo. Why have it in stereo for rear? Seems like a lot of people agree with the mono point.
You think 125hz and up would be good? 12db or 24db slope?
 

·
Registered
Joined
·
18,420 Posts
I can change it on the fly and I seem to always go back to momo. Why have it in stereo for rear? Seems like a lot of people agree with the mono point.
You think 125hz and up would be good? 12db or 24db slope?
Not stereo.. Left MINUS right. No mono information at all. What processor do you have

Sent from my VS988 using Tapatalk
 

·
Registered
Joined
·
2,581 Posts
Also, I have an Audi A4 sedan. No rear fill feels like something is missing. Even though its subtle its better in bigger cars I think. Id never do it in a coupe.
What year A4? I have a 2006 A4 Avant, working on getting rear fill set up correctly at the moment. I have mine from 300Hz up to 3000Hz at the moment.

It's definitely tricky getting them right, at first I did not even notice they were on at all, muting them made no difference to the sound. I increased the gain at the DSP and now I can hear them, but they do not pull anything rearwards. I may dial them back down a little though, but going to leave it for a while to see how I like it.
 

·
Registered
Joined
·
122 Posts
What year A4? I have a 2006 A4 Avant, working on getting rear fill set up correctly at the moment. I have mine from 300Hz up to 3000Hz at the moment.

It's definitely tricky getting them right, at first I did not even notice they were on at all, muting them made no difference to the sound. I increased the gain at the DSP and now I can hear them, but they do not pull anything rearwards. I may dial them back down a little though, but going to leave it for a while to see how I like it.
its an 2010 a4. Also made a ski passthrough for it once I noticed how much better the sub sounds with the side drivers rear seat folded down.
Similar with mine I don't notice them much. I have them a tad lower than the normal volume but time aligned it sounds like its coming from the center stage.
Using a center speaker and I swapped my components to coax(component convertibles) the sound stage sounds much much better than in the pillars.
 

Attachments

·
Registered
Joined
·
18,420 Posts
Yeah the audiocontrol processor can't do left minus right. Hell, it doesn't even do left/right eq :(

Sent from my VS988 using Tapatalk
 

·
Registered
Joined
·
122 Posts
Yeah the audiocontrol processor can't do left minus right. Hell, it doesn't even do left/right eq :(

Sent from my VS988 using Tapatalk
yup not yet at least. Ill be testing some of that beta software for them in a few weeks they said they should have it available. Still having some issues right now
 
21 - 40 of 61 Posts
Top