Tweeters in-phase?

Have a pair of Quart tweeters mounted in the dash firing straight up to the glass, then reflecting back to my ears.  Does this put them out of phase?  I haven't played with it much, but I presumed I'd never hear a difference in-phase or not when they're crossed at 1k.

There's a second set in the rear doors firing inwards, actually at a 90 degree angle to the dash tweeters off the glass.

I guess this will be a pretty theoretical question if anyone can even answer it.  Thanks.

This will not effect the phase. Usually  hooking one up backwards will do that.

To be honest, I don't think you would be able to tell anyway.

The easiest way to see if they are out of phase or not is to play them as is, then switch the polarity on one of them, and try again.  Whichever is louder highs is in phase since when you put speakers out of phase, they effectively cancel a good portion of themselves out.

Sound quality is excellent - very crisp & defined, excellent staging, no fatigue at volume for long periods.  It constantly amazes me how good it sounds.  that said, I'm not really trying to solve a problem, just curious about phase "theory" after the waves reflect off of a 45 degree angle, then head towards a different set of drivers playing in a different axis.

The setup is this - '99 Jeep Gr Cherokee w/2 sets Quart 6.5 seperates (the "Reference" series) in F&R doors, the front tweeters in the dash, driven by 2 Soundstream 10.0 class A's @ 4ohm/100wpc.  X-over frequency is whatever the passive Quart x-overs set it at, I think it was 1k, could be 2k?   It's the same front & rear.  JL Stealthbox with a 10" W3 & a Soundstream Rubi throwing another 4-500w that way, actively crossed at 90hz.  Front tweeters are bright, so they're set to -6db.  Rear drivers aren't directly in line with my ears, so I play with the fader a bit to dial them in.

I've no doubt what the consequences of the low end being out of phase & how that cancellation would sound.  I've never known much about how the tweeters would sound out of phase, but I agree that it would probably result in long-term fatigue at the least.  So again, kinda lookin' for some theory from someone smarter than me. 

One day I may get around to pink-noise-ing the set-up, but a little afraid that I'd find a new problem & have to fix that, being a perfectionist.  Can anyone relate to that?  Thanks for the feedback.  Can anyone help with the turn-off thump?  That's really bugging me - check other posts.

Have a great weekend.

geepherder pointed you in a direction that will solve the problem.  As Nike says - "just do it".

Yeah, there have been numerous anal compulsive perfectionists frequenting this board (I'm not one of them) and some still lurking and contributing gold.  Sometimes it takes that kind of mentality to solve problems from afar, like over the internet.  Sometimes, though, it goes too far like when it's your own audio system and you are too severe of a critic.  Your first two sentences in the above post spells out your findings clearly:  don't keep messing with it.  Time to relax and enjoy!

I can relate to the perfectionist thing, but really... if it sounds fine, I wouldn't worry at all about phase.  There are a bunch of people that want phase to perfect, but there's another school of thought that says phase doesn't matter too much if the resulting frequency response is in the right ballpark.  I'm with the second school, especially in-car. 

On the crossover frequency, the passive Quart Reference set is much higher than 1khz.  Try 4.2khz.  See here: http://www.mbquart.com/2003/en_US/mbtech/car_cross_specs.asp  This is actually a -really- good thing for you.  Why?  Because any phase problems based on tweeter positioning are outside of the critical 250-3000hz listening range that really shapes the music and where are ears are the most sensitive.  Your tweeters won't be a full 12db down by 3khz, but they'll be quite attenuated compared to the midrange.  I wouldn't worry about the phase problem.

What one thing might I worry about with a crossover frequency that high and your tweeters positioned like they are?  A frequency response dip between where your midrange starts to rolloff when it is off-axis and where the tweeter picks back up.  This gap could have the tendancy to make your tweeters seem even brighter than they should be relative to your midrange and make your sound seem a bit separated.  In many systems set up the way you describe, there's a tendancy to really be able to pick out the fact that the midrange and tweeters are coming from different sources.  This shouldn't be noticable.  Anyway, I think this actually probably a more serious problem for you than phase, depending on how off axis your midrange speakers are.  How off axis are they?

On both issues, it will all probably boil down to how nuts you become over car audio and getting it perfect.  If either issue is important enough to you, you'll move the midrange and tweeter to the kick panels, with the tweeter as close to the midrange as possible, and both as on-axis as possible.... So, how badly has the audio bug bit you?

Cheers  :-)

Good info KFR01, sounds like you really know your stuff.  The passenger door mid is dead-on axis, my door is about 60 degrees off.  that creates a bit of a hole, but not too bad.  You may have something about a dip at the xover point tho, the tweeters do tend to be bright up there.  Maybe I should do that pink noise test.

there is a lot of seperation in the sound, but in a good way, not annoying - more like a good soundstage presence.  The signal processor I use is an Audiocontrol HPX, basically an expansion circuit.  It's the only one that brought life back to MP3's without making it sound too "hot" and annoying.  I like to believe this is creating a lot of the seperation I hear. 

I do hear a different location for mids & tweeters, but the net effect feels more like instruments being spreadout on the stage rather than listening to equipment spread across the stage.  Does that make sense?  My goal is ultimately to listen to the music, not the gear reproducing it.

BTW, nice system you've listed there.