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Discussion Starter #1
My experience has shown that most people set up their left and right drivers symetrically with respect to an imaginary centre line down the middle of the vehicle.

This means that one driver is usually more on axis that the other when viewed from the driver's seat.

I would imagine that this creates issues with the left vs right frequency plots we get with associated imaging anomalies and 'bugs' (some songs sounding evenly centered and yet others not, and other issues when moving our head just a fraction away from the 'sweet spot').

How many people mount things asymetrically so that the frequency response from each driver is the same?

For those that mount drivers symetrically, how have you compensated the different left vs right frequency plots?
Different eq for left vs right?

Thanks everyone.
 

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This is a great question that I would love to learn about.

I will soon be working on pillars for my car and will have to make a decision on how to aim them.
 

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My experience has shown that most people set up their left and right drivers symetrically with respect to an imaginary centre line down the middle of the vehicle.

This means that one driver is usually more on axis that the other when viewed from the driver's seat.

I would imagine that this creates issues with the left vs right frequency plots we get with associated imaging anomalies and 'bugs' (some songs sounding evenly centered and yet others not, and other issues when moving our head just a fraction away from the 'sweet spot').

How many people mount things asymetrically so that the frequency response from each driver is the same?

For those that mount drivers symetrically, how have you compensated the different left vs right frequency plots?
Different eq for left vs right?

Thanks everyone.
I can tell in general sound terms from my own experiences is that there will always be songs that sound great, but also there will always be songs that sound not so great.

I think the way to compensate for the drivers is through the use of time alignment granted you have the EQ tuned properly. How I have always did it is I first lay out a plan of where I would like to mount the drivers and I then I do my best to bring that thought to life. Once that is done I use EQ and time alignment to adjust and center in the image. A lot of what we do here on diyma is not like a typical car audio forum. A lot of what I do and I see here is theory and science based so it's basically a trial and error type deal.
 

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First let me say I know that the only true way to find what works in any specific vehicle is to experiment and listen. I get that. With that said though people smarter and with more experience can guide guys like me in the right direction based on their knowledge.

So yes, time alignment is always in the equation due to PLDs to achieve as good of an image as possible. TA is a band aid though in the car environment. Since you can't TA for two seats with the same numbers then you really are making a one seater right? If it's a one seater and you've accepted that then would aiming the tweeters more specifically for the driver's seat help?
 

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There was that crazy white panel van that Car Audio and Electronics did a few spreads on. He has those huge A pillars done with I believe DYN speakers. He spent huge amount of time getting it to sound correctly, and each article showed the math and angles hes used to achieve what they called perfect SQ. Going by memory, I do believe each pod was aimed at different angles on top of having time alignment. I think for the average guy time alignment is probably a must, but to get it truly right you would also experiement with different angles.
 

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It definitely depends on the drivers you are using (do they prefer on or off axis, how is the top end roll off, etc) and your EQ ability (do you have plenty of bands to play with, separate L/R EQ, etc). For me, aesthetics won out and I did mine symmetric and somewhat off axis.
 

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Discussion Starter #8 (Edited)
Thanks for the link to the Toyota build thread. I'd read that whole thread previously and found it very interesting.

After posting this thread last night I got to thinking.

I came up with the drawing at the bottom of this post using a friend's Toyota RAV4 for inspiration. It's drawn up after measuring up the inside of my Honda. This is the only arrangement in my car where I can maintain equal off axis positioning for each driver AND not have to mount the drivers too far off axis (thus sacrificing frequency response - particularly top end).

I know that there's must more to what I hear than just the immediate sound from the drivers and I know that real life experimentation will tell alot.

In the system I am building however, I'm wanting to get the primary sound sources (drivers) mounted and functioning correctly, then I'll deal with the boundary defraction issues that plague every car audio system.

In my favour is the fact that I've gone for cones (Audible Physics XR3M wide band drivers run 250Hz - 20Khz) now instead of domes. However, it is my view that whilst cones help somewhat in avoiding absolutely immediate boundary reflection if mounted correctly because of how they project the sound, it is also for the same reason more important to ensure that each side is mounted with the same angles (either on, or off axis) relative to the driver's seat.

In my system, form still has quite a degree of influence and it's for this reason that I wanted something that looks symetrical while at the same time being set up with an equal axis setting for left and right.

I believe that with the measurements and angles in my drawing below, I should have things pretty spot on.

As it turns out, my wide banders actually plot smoother at between 14 and 18 degree off axis (on axis has a rising response above about 15Khz).
The way I see it, when I mount them this way with both drivers the same angle off axis to me, if I find the top (or any other area) needs a tweek, I'll not have to separate eq for each side.

This keeps things simpler. Well, that's the idea at least. I guess I'm just trying to learn and understand the theory behind it all so I have a better chance of getting things right straight up, if possible.

And with regard to my drawing yes, we drive on the left here in Australia
 

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Always remember K.I.S.S.!!! Unless you are planning to compete it seems like a lot of work. A lot of the projects I think of now seem to be more for what if purposes than anything else (neo10's).
 

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Discussion Starter #10
The system will be used in MEASQ (Australia's competition format) Advanced (think top level in IASCA, etc) competition for the 2012 year.

I've been a judge with the Queensland State division since 2005.
 
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