# Kicks minimize PLD's



## 07azhhr (Dec 28, 2011)

I posted this in another thread but thought this might be a good discussion topic for it's own thread. 

Ok since PLD's and kicks are mentioned so much in relation to the need for TA I decided to measure the distances to the drivers ears in both my car and my girls car. Note that neither car is using kick locations. 

I used my mic in my normal testing location to use as the head position for these measurments.


My car HHR:


TW's and MR's in pillars MB's in doors


LTW = 38 RTW = 51.5 total PLD = 13.5

LMR = 40 LMR = 53 total PLD = 13

LMB = 42.5 RMB = 55 total PLD = 12.5

LKK = 54 RKK = 64.5 total PLD = 10.5

SUB = 52


So roughly a 2.5-3 inch improvement on PLD hmmmmmmm not very much IMHO.



Saturn Ion


TW's in pillars MB's in doors


LTW = 40 RTW = 51 total PLD = 11


LMB = 41 RMB = 56 total PLD = 15


LKK = 50.5 RKK = 60.5 total PLD = 10

SUB = 67


In this case there is a 1 - 5 inch difference so again not a huge reduction in the PLD's with the PLD's for the kicks still at 10".





So both cars still have 10" differences in PLD's down at the kicks. Mind you I was going for the furthest most distance possible in the kicks in both cases. To me these are not really going to help with PLD's from a TA stand point like they are made out to be. What they will help with is moving the speakers past the windshield which allows for a stage that extends past the windshield. Otherwise the numbers do not add up for minimizing PLD's like many try to say they will. 


Also to note sub distances are not always the farthest speakers. In the HHR the sub is on the left wall middle of the hatch area and is closer then the RMB. In the Ion the sub is in the far back left corner pocket so yes it is farthest speaker BUT if it was up against the back seat like many subs are it would be closer then the RMB just like in the HHR.


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## [email protected] (Jun 12, 2008)

Mine would be 

25" to left tweet in apillar 43" to right tweet in apillar 18" dif

46" to left kick 54" to right kick 8" dif

That minimizes PLD's by alot IMO. Mine is a Infiniti FX35


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## 07azhhr (Dec 28, 2011)

That is certainly an improvement over your pillars. 

I guess I should add that this stems from people saying this will reduce the need to use TA. Having an 8" difference does not remove that need. 

I guess I should edit the first post to include the TA part.


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## bbfoto (Aug 28, 2005)

There are other factors as well besides just T/A...

L/R Amplitude Balance

Dispersion/Polar (Frequency) Response differences between L & R at the listening position.


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## 07azhhr (Dec 28, 2011)

bbfoto said:


> There are other factors as well besides just T/A...
> 
> L/R Amplitude Balance
> 
> Dispersion/Polar (Frequency) Response differences between L & R at the listening position.


 
Care to add more of an explaination on these things?


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## 07azhhr (Dec 28, 2011)

BeatsDownLow said:


> Mine would be
> 
> 25" to left tweet in apillar 43" to right tweet in apillar 18" dif
> 
> ...


 
Beats are you sure about that left tweet distance? That just seems to be really really close to your head. Maybe I should ask how tall are you?


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## [email protected] (Jun 12, 2008)

07azhhr said:


> Beats are you sure about that left tweet distance? That just seems to be really really close to your head. Maybe I should ask how tall are you?


I am pretty certain those are correct. I am 6ft tall. That would be my driving seat position.


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## 07azhhr (Dec 28, 2011)

Are you itting straight up and down and are your tweets at the top of your pillars? I am only 5'9" and my seat is pretty upright and my tweets are in the middle of my pillars height wise and I am nearly 15" farther then you in a similarly shaped car A pillar wise.

My girl is only 5'3" but her car shape is drastically different then both of ours.


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## [email protected] (Jun 12, 2008)

Straight up and down as I get  I will see if I can get a minute after work before it gets dark to snap a pick. I think it might just be a difference of the dash shape.


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## 07azhhr (Dec 28, 2011)

I would like that. Also take a tape measure with you .


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## 07azhhr (Dec 28, 2011)

bbfoto said:


> There are other factors as well besides just T/A...
> 
> L/R Amplitude Balance
> 
> Dispersion/Polar (Frequency) Response differences between L & R at the listening position.


In regards to the amplitude balance. Perhaps if you are making them be on the same axis to the drivers ears but still a 10" difference in distance is going to cause a amplitude imbalance/difference.

In my cars case there is only a 2.5" difference or improvement between my MR pillar location and the kicks if I were to move them down there. Do you really think there would be much improvement? I would still have a 10" PLD between MR drivers. 

Now if Beats measurements are correct then I could understand there to be a decent improvement. 

The thing I am getting at is that people make it out to be as if both drivers would have almost no PLD to begin with.

So I guess a new question would be how many cars actually end up with very little PLD when using kicks?


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## Niebur3 (Jul 11, 2008)

Mine (2004 Acura TL) are - I did a-pillar vs kick instead of door:

Seat in Driving position:

40" to left tweet in a-pillar 54" to right tweet in a-pillar 14" dif

53" to left kick 62" to right kick 9" dif

Seat as far back as it goes:

46" to left tweet in a-pillar 56" to right tweet in a-pillar 10" dif

57" to left kick 63" to right kick 6" dif

Jerry


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## thehatedguy (May 4, 2007)

Depends.

With my seat back in a judging/listening position, the differences are a lot smaller than my driving position. I know that with my horns in the listening position, I have somewhere like 6-8" difference...and roughly similar with the mids. I would have to go find a tape measure to remeasure to be positive on the exact numbers.

But the differences are greater in the driving position.


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## Niebur3 (Jul 11, 2008)

Has anyone found a common ratio (if there is one) to distance between PLD's and distance image if off from center assuming no T/A?


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## thehatedguy (May 4, 2007)

No, but I don't think I have ever paid it any attention.

But the smaller the PLDs are, the better off you will be in terms of such things. And if you can get down to like 8" differences or less then you are off to a really good start.


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## 07azhhr (Dec 28, 2011)

That was a great addition Jerry, Hated. 

I would be curious about the ratio too Jerry. 

I should test my girls car at my driving position tomorrow (now at work) and see what the difference is as well as seat full back in both. I wonder if it is ever possible to get them the same without resorting to different mounting locations in the kicks? i.e. the right being more towards the door vs the left nearest the firewall.


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## 07azhhr (Dec 28, 2011)

thehatedguy said:


> No, but I don't think I have ever paid it any attention.
> 
> But the smaller the PLDs are, the better off you will be in terms of such things. And if you can get down to like 8" differences or less then you are off to a really good start.


 
Why 8"? Wouldn't you still have noticable differences? Or is that where it seems to be close enough persay?


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## thehatedguy (May 4, 2007)

http://www.diymobileaudio.com/forum...ussion/60146-creating-perfect-soundstage.html


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## Orion525iT (Mar 6, 2011)

I think there is some confusion in this regard. 10" PLDs in the pillars does not correlate to 10" PLDs in the kicks. Its not an arrival time issue, it a distance ratio issue. This is because, although the PLDs dont change, the angle of the speaker does. This then brings in dispersion characteristics of the driver, L/R level matching and eq capacity. 

But in my car, the PLD differences between pillars and kicks is also substantial. Ill post measurements later.


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## Oliver (Jun 25, 2007)

> 0-2009 #18
> Eric Stevens
> DIYMA 500 Club
> 
> ...


He understands this ^^^^ subject.


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## 07azhhr (Dec 28, 2011)

Orion525iT said:


> I think there is some confusion in this regard. 10" PLDs in the pillars does not correlate to 10" PLDs in the kicks. Its not an arrival time issue, it a distance ratio issue. This is because, although the PLDs dont change, the angle of the speaker does.


Correct me if I am wrong here but you can vary the amount of on/off axis of either location. Unless that is not what you are meaning.


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## 07azhhr (Dec 28, 2011)

thehatedguy said:


> http://www.diymobileaudio.com/forum...ussion/60146-creating-perfect-soundstage.html


I will have to see if I can read that thread tomorrow.


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## 14642 (May 19, 2008)

It's pretty simple. A PLD of one foot puts the first notch in the comb filter at 2kHz. THe comb is a bigger imaging problem than it is a frequency response problem because the speakers are out of phase at that frequency. Below that, there's no comb. Because the distance between our ears is about 7-10 inches, we don't hear phase very well (for localization) between 1 and 3k, and we don't hear it very easily above that because the wavelengths are so small. 

So, kick panels help get the mids closer to being in phase. They also move the speakers away from the worst of the reflecting surfaces (windshield and windows).


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## Orion525iT (Mar 6, 2011)

07azhhr said:


> Correct me if I am wrong here but you can vary the amount of on/off axis of either location. Unless that is not what you are meaning.


You could face them 180° away from you in the pillars or the kicks, this is true . 

The pillars are typically a more narrow location. Reflection are a substantial issue with pillar mounts. Distance ratio of kick locations are typically less. Sound power response. Together, these factors typically limit the angles that will work for pillars over kicks without tons of processing even if PLDs are identical between the two locations. And processing wont address reflections or fully correct for power response.


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## Bayboy (Dec 29, 2010)

Wasn't there a big thread on this?? Can somebody post up the link?


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## RNBRAD (Oct 30, 2012)

Andy Wehmeyer said:


> It's pretty simple. A PLD of one foot puts the first notch in the comb filter at 2kHz. THe comb is a bigger imaging problem than it is a frequency response problem because the speakers are out of phase at that frequency. Below that, there's no comb. Because the distance between our ears is about 7-10 inches, we don't hear phase very well (for localization) between 1 and 3k, and we don't hear it very easily above that because the wavelengths are so small.
> 
> So, kick panels help get the mids closer to being in phase. They also move the speakers away from the worst of the reflecting surfaces (windshield and windows).


Then they bring their own issues. Pick your poison I guess.


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## Bayboy (Dec 29, 2010)

http://diymobileaudio.com/forum/showthread.php?t=5664


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## 07azhhr (Dec 28, 2011)

Andy Wehmeyer said:


> It's pretty simple. A PLD of one foot puts the first notch in the comb filter at 2kHz. THe comb is a bigger imaging problem than it is a frequency response problem because the speakers are out of phase at that frequency. Below that, there's no comb. Because the distance between our ears is about 7-10 inches, we don't hear phase very well (for localization) between 1 and 3k, and we don't hear it very easily above that because the wavelengths are so small.
> 
> So, kick panels help get the mids closer to being in phase. They also move the speakers away from the worst of the reflecting surfaces (windshield and windows).


Thank you Andy. I will have plug into my midrange amp and see what eqing I have done in that area since I am right at that 12" mark.




Orion525iT said:


> You could face them 180° away from you in the pillars or the kicks, this is true .
> 
> The pillars are typically a more narrow location. Reflection are a substantial issue with pillar mounts. Distance ratio of kick locations are typically less. Sound power response. Together, these factors typically limit the angles that will work for pillars over kicks without tons of processing even if PLDs are identical between the two locations. And processing wont address reflections or fully correct for power response.


I cut away a majority of my pillars and sunk my drivers in as far as I could to get the most width out of them. But my kicks have these nice pockets in them that would fit my 3's. But it would move them closer to me and might make the PLD increase to 12 or so.But that would be right were they are now . Not to mention but I have a ton of electrical connectors, my main power cable to my engine bay (stock battery in in the hatch) and my hood release are in the way of that pocket . I do worry about my legs though, blocking sound from the drivers mid if I was to use the kicks. I literally can not see the potential speaker location in the drivers kick while I am driving and that seems like it would drastically change my stage, give me issues when I am driving. My stage height and width are very nice. It is my depth that is lacking and that is where kicks would probably most benifit me. But again I worry about blocking the left mid with my leg. I do not seem to have reflection issues up top so that seems to be moot in my case. 

But I have to say that this thread is really making me want to make some baffles and try the 3's in the kicks just to see.


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## Orion525iT (Mar 6, 2011)

07azhhr said:


> I cut away a majority of my pillars and sunk my drivers in as far as I could to get the most width out of them. But my kicks have these nice pockets in them that would fit my 3's. But it would move them closer to me and might make the PLD increase to 12 or so.But that would be right were they are now . Not to mention but I have a ton of electrical connectors, my main power cable to my engine bay (stock battery in in the hatch) and my hood release are in the way of that pocket . I do worry about my legs though, blocking sound from the drivers mid if I was to use the kicks. I literally can not see the potential speaker location in the drivers kick while I am driving and that seems like it would drastically change my stage, give me issues when I am driving. My stage height and width are very nice. It is my depth that is lacking and that is where kicks would probably most benifit me. But again I worry about blocking the left mid with my leg. I do not seem to have reflection issues up top so that seems to be moot in my case.
> 
> But I have to say that this thread is really making me want to make some baffles and try the 3's in the kicks just to see.


I think some newer cars change the PLD argument. I was sitting next to a Prius the other day and noticed how long the dash and glass extended out over the nose. But its a narrow angle between the dash and windshield. So even if the dash stretches out further, getting drivers to fit will still be a challenge...and reflections still pose a major issue.

I dont know how others get around the issue of early reflection with dash and pillar mounts. I have tried my tweets up high, and they initially sounded pretty good. But I noticed that listening fatigue set in early, and after awhile it seemed I was so keyed into the fuzziness of the near reflections that I couldn't stand it. Beyond that, the stage was centered but width and depth was an issue.

I then put everything in the kicks, and got good results. But even, then early reflections were an issue. After getting my angles on the mids and fabing the kicks, I started to experiment with sound absorbing foams on the under side of the dash. I thought that equal application of foam on both sides would not impact the stage adversely. I was wrong, the stage was now pulled down and to the drivers side. It was an eye opener as to what near reflections can do. The stage I worked so hard to produce was still created and hampered by near reflections.I reangled the kicks, added a bunch of eq at 14k and took a bunch out at 60hz and 150hz. 

As it sits now, the sound is smoother across the board, the stage is wider and deeper. On some songs, female vocals float at the top of the windshield. Tonality is better. The stage still pulls to the left, but there is a rats nest of wires (which I lengthened to clear the kick pods) that dangle half a foot or so from the drivers mid. Once that is cleaned up, I expect the stage to improve even more.


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## 07azhhr (Dec 28, 2011)

That is very interesting. 

I do not have issues with my stage pulling. It stays up on the dash and extands just outside the left (drivers) window and over to the middle of the right pillar (by middle I mean from the speaker grill to the weather stripping that the pillar molding goes into). The acoustic center line is is under the left side of the rear view mirror. I also do not get listening fatigue at all. The only thing I am wanting or lacking is depth. I am stuck at the windshield. That would be the main and perhaps only reason for me to go into the kicks. If I were to drw a straight line down from the mids in the pillars to the kicks the line would match exactly how far out the kick moldings come out from the body panel. So I would not gain any more width then I already have since I sunk my speakers into my pillars insted of building my pillars out like many do. But like I said I can not even see the majoruty of my left kick when I am in the car and since it is a stick I would be moving my leg all the time. I want to try it but I fear/suspect that my leg would cause issues.


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## Bayboy (Dec 29, 2010)

Why not use some sort of temporary pod just to see what happens? The cabin in the S10 is quite narrow to where the pillars offer little width with off-axis tweets. The MS62c performs well but is not well suited for this. The kicks and upper doors will probably be next in line but will require some higher output small drivers that can be set in the metal for room down there is scarce. Door... well, don't want to even talk about that! That's what the BMR12 are for... shallow pods on the panel surface for trials or dash/pillar on axis.

Trials trials trials....


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## 07azhhr (Dec 28, 2011)

Temp baffles are next but right now I am working on my amp rack then I have a new sub box to build. After that I may try the kicks.


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## Orion525iT (Mar 6, 2011)

07azhhr said:


> But like I said I can not even see the majoruty of my left kick when I am in the car and since it is a stick I would be moving my leg all the time. I want to try it but I fear/suspect that my leg would cause issues.


You just gave me a great idea; Replace my big honking auto break pedal with one from a manual. The manual pedal is half the size and is not offset to the left like the auto. Considering I have the pedal box in the shed right now, I am not sure why I didn't think of it earlier.

Kick panel build #2000 and something.


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## BiggDaddyTL (Apr 13, 2013)

Orion525iT said:


> You just gave me a great idea; Replace my big honking auto break pedal with one from a manual. The manual pedal is half the size and is not offset to the left like the auto. Considering I have the pedal box in the shed right now, I am not sure why I didn't think of it earlier.
> 
> Kick panel build #2000 and something.



Now that is thinking with your dipstick Jimmy!


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