Mounting tweeters on or off axis

[TheSundownFire]

Im kicking around some new placement for my components and Im think mid woofer in the door and the tweeter in the mirror sail.

the area circled in red:

Now what Im wondering is should I mount the tweeters flush with the sail and off axis with the driver or mount them on axis?

[R_Mac_1]

I'm interested in some inputs on this as well. I actually have my tweeters in my sail panel right now (off axis) and was thinking about molding them into my a-pillars but was wondering whether to try to position them more on-axis or whether to leave them off-axis.

[jjones91]

That's where I plan on putting mine. I planned to fiberglass that piece with 2 in each one. What does the whole off axis thing mean exactly? I'm a noob.

[AI James]

its pretty dependant on your component set, some sound better off axis other sound better on axis. best thing to do is velcro or double sided tape the tweets and test placement til your happy

[R_Mac_1]

That's where I plan on putting mine. I planned to fiberglass that piece with 2 in each one. What does the whole off axis thing mean exactly? I'm a noob.

Basically on-axis means the tweeters would be pointing directly at you where as off-axis they aren't. Mine are currently in my sail panels pointing basically straight across the car at the other sail panel (off-axis).

[jjones91]

Basically on-axis means the tweeters would be pointing directly at you where as off-axis they aren't. Mine are currently in my sail panels pointing basically straight across the car at the other sail panel (off-axis).

Oh, ok, thank you.

[Nirvalica]

If your tweeters swivel, then you don't have to worry about that...

[TheSundownFire]

I like the velcro idea so Ill try that out.

I was under the impression that on axis was at the driver or passenger so Im glad I was corrected.

[raytard]

some fire straight across, some aim at the dome light, some aim at the oppisite side's inside ear (passenger tweeter aimed at driver's right ear, driver tweet aimed at pass left ear), some mount low, some mount high, some bounce of the windshield.

atleast in my own experience, the two that seem the best are in a kickpod aimed at the domelight, or sail/a pillar aimed at domelight.

experiment though, every tweeter/crossover/car is different and what works for one may suck for another. knock off all your armorall and get some blue-tac (remember that silly putty stuff from gradeschool that you hung up pictures with before they trusted you with thumbtacks?) and start sticking them in places and testing...

[Neel]

It will be difficult to have a balanced stage if you have your tweeters in your a-pillars with no signal delay or level control. For the most part there are two factors that come into play here, inter-aura level difference (ILD) and inter-aural time difference (ITD). So you brain localizes sounds laterally using these two factors for the most part, I do not understand head related transfer function or the other stuff well enough to write about it. In your situation, I am pretty sure you can adjust levels of each tweeter individually with the 9886 as well as use signal delay to correct the path length difference. The reason why raytard has good experience with tweeters in kick panels is because the kick panel location in most vehicles provides the most equidistant path lengths for speakers in relation to the listener. So if you have NO signal delay and you have your tweeters in your a-pillars, the driver side tweeter is maybe 3ft away from your head and the passengers side tweeter is maybe 6ft away from you....see the issue there?! So the brain will recognize this inter-aural time difference and whatever frequencies your tweeters are responsible for will pull to the driver side. Put your tweeters in your kick panels and you get rid of the issue of having extremely different path lengths for the speakers. This why you see lots old SQ cars with drivers in the kick panels -- simply because in the early 90s signal delay was not as readily available as it is now so competitors had to optimize speaker locations in order to get good sound.

As for the on or off axis , a lot of this will depend on the driver itself. If it has a good off axis response , it will sound great off axis (as long as you are crossing over the driver before or after it beams) -- if it has a poor off axis response , it will sound bad off axis. Beaming is a very simple thing that all speakers do..here is a quote from Steven Kepharts Comprehensive Front Stage Setup that sums up beaming quite well,

" Beaming occurs as a drop in the off axis response of the driver. The further off axis you are, the more of a dip there is. The frequency the driver starts to beam at is determined by D^2/lambda. As an example, a 6.5" driver will start to beam at around 3.2-3.5 kHz. This is important to keep in mind when selecting a driver if you plan on using it up that high. "

So the best thing I can tell you to do is try installing them in the A-pillars only if you have the ability to delay them separately from the mid -- are you running active? Otherwise, keep it simple and put them low in your kick panels. The trade off here is that in your kick panels they will have closer to equal path lengths so your stage will be more balanced however they are more susceptible to being blocked by your leg while you are driving and that can cause issues. With the tweeters in the a pillars you will have more window reflections to deal with.

Sorry for the long post, I just feel like there are too many people telling you what to do and not giving reasons on why their suggested method will or will not work. There is no right answer, so now go out and experiment logically using the information given above and in my references linked below.

http://www.usdaudio.com/tutorials/imaging.php - Eric Holdaway / Rob Greene Imaging Tutorial

http://www.the12volt.com/installbay/forum_posts.asp~TID~78597~PN~1 - Steven Kephart Comprehensive Front Stage Setup