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Imaging?

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Old 09-17-2004, 03:09 PM
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Am I the only one that can't get tweeters crossed over above 6khz to image?

I'm becoming very skeptical of the benifits of Time alignment at the highest end of the frequencey spectrum. So far, I'm finding aiming, and intensity to be the most benificial when tuning tweeters. All in all, the "air" that tweeters bring from 8Khz up seems to be even less directional then a 20hz sub bass note. (meaning imaging seems to be non existant in that frequency range, not that the tweeters can not be localized by their position.

Any thoughts on this guys?

Adam
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Old 09-17-2004, 04:57 PM
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Ahh young grasshoppa that is why the A-pillar tweets are for air only, to raise the ambient height of the stage.

Imaging cues are primarily from 150 Hz to approx 6000 Hz..and as you and I have discussed, that is the reason I intend on making sure the location those frequncies originate from is as close to a single pointsource as possible, in the best possible location for pathlenghts...then comes the accuracy of the drivers and enclosures, controlling dispersion, and early reflections, all idealized for that specific 150-6000Hz location. If this is sorted out properly it should be a lot easier to add A-pillar tweets for air, and midbasses playing the a very narrow range at frequencies not as critical to placement for pathlenghts( mine 40-100 and up to 150 Hz Hz)and finally sub bass to your personal taste.
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Old 09-17-2004, 09:49 PM
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Yes generally speaking, pathlengths become less important as you go higher up in frequency, when axis and intensity become more important.
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Old 09-18-2004, 04:56 AM
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adam,
there are some rather amazing posts on carsound (sq competition moded by Mark Eldridge ) dealing with this and various related issues. do a search on a pillars and you'l get gold! Scott Buwalda posted extensively on the subject (and not just lame *** responses... tons of great content!
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Old 09-18-2004, 05:24 AM
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Thanks Mr.Marco.

I was just thinking out loud. I've read the posts, and I've been in contact with Scott B. over the past month or so regarding tweeters. He and I share some rather interesting points of view.

Maybe I'll do some digging over there and post some links here.

Adam
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Old 09-18-2004, 11:44 AM
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i wish i could have done it but i was gonna be late for work if i dug them up. actually a while back i posted a link to your Door picture post there as some people were inquiring about exactly that same process.
Scott definetly knows his ****... gave me some interesting advice on imaging my pods. he;s damn addictive, everytime i'd email him he'd include another juicy bit of information...

Adam,
are you only using 2 tweets?
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Old 09-18-2004, 12:18 PM
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There are physically 3 sets in my car right now...although only 1 pair is running.

[img]smile.gif[/img]
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Old 09-19-2004, 02:32 PM
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Originally posted by islandphile:
Ahh young grasshoppa that is why the A-pillar tweets are for air only, to raise the ambient height of the stage.

Imaging cues are primarily from 150 Hz to approx 6000 Hz..and as you and I have discussed, that is the reason I intend on making sure the location those frequncies originate from is as close to a single pointsource as possible, in the best possible location for pathlenghts...then comes the accuracy of the drivers and enclosures, controlling dispersion, and early reflections, all idealized for that specific 150-6000Hz location. If this is sorted out properly it should be a lot easier to add A-pillar tweets for air, and midbasses playing the a very narrow range at frequencies not as critical to placement for pathlenghts( mine 40-100 and up to 150 Hz Hz)and finally sub bass to your personal taste.
"I see.." said the blind chinaman.

So, if one tweet is used to image, another tweet on the a-pillar to raise ambient soundstage... Adam, what is your 3rd tweet for?

Assuming there is a tweet in the kick, would it be wise to cross it between xHz - 6000Hz? and let the one on the a-pillar take over from 6kHz and up?

And Islandphile, regarding reflections, what can be done in an automotive perspective? Re-upholster the plastic in a thick velvet? mmm velvet.
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Old 09-19-2004, 05:37 PM
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I'm playing with a couple of sets of tweeters. While I'm only using one pair at a time right now, I'll be playing with using 2 sets of tweeters shortly.
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