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Discussion Starter · #1 ·
Do you feel that speaker phase relationships are underrated?

I do.

When I first began car audio, I had no idea that "phase" even was an issue. I threw some components up front, wired them to my amp, and was done.

However, now knowing what to look for, and using phase tracks to determine correct relationships, I think its a huge factor for imaging. I can really screw up the sound from switching phase.

That brings me to my next question as well. When setting correct phase relationships, what is the correct order,or, is there even an order to go by?

I did phase work today and ended up doing woofer to woofer, mid to mid, tweeter to tweeter, followed by woofer to mid, mid to tweet on the left and right channels.

Anyways, please discuss :D
 

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Fixing phase SUCKS!!!!

So many things affect phase that it's nearly impossible to combat all of them. We'll focus on two of the Impedance, and Distance.

As impedance changes so does phase. One of the benefits of your system is the relatively flat impedance curve of the 8945P within the bandwidth you're using it for. Obvious boon there. Another driver with a steeper impedance rise on the top end would have had a different phase interaction at the crossover point.

Next, is distance. This is simply the lining up of the drivers. What's the difference in distance between two different drivers? This is more critical in lower frequencies. But can be an issue for higher frequencies. ESPECIALLY in two configurations where you have a higher impedance on the mid, and an offset in distance. A 3-way setup with a midbass and midrange could have some serious phasing issues with a lowish crossover point in the 200 hz range due to distance.

There's really no right way to combat poor phase relationships. The fact that you're doing it at all is a credit to your determination.

Play with different slopes, and different crossover points. Obviously you don't want to go too low with your crossover point with a 6db (1st order) slope. But play around. If you lower your slope, try raising your crossover point.

It was common practice to build passive crossovers for car component sets with a 12db slope on the woofer, and 18 db on the tweeter. This would create a 90 degree phase shift that would allow you to swap phase on the tweeter. The idea was that for a woofer in a door and a tweeter in the sails, you'd have a big offset in distance between the two. The ability to shift the phase of the tweeter 90 degrees in either direction would, in theory, create an almost phase perfect situation. A typical 18db/18db crossover could achieve the same sort of result.

CDT's underhanded marketing uses 18 db slopes and calls them "Phase Perfect" slopes for exactly that reason. They also call them 60 db, which in a way is correct, but in reality it's an 18 db slope. The Phase Perfect part of it is for the reasons above. In reality a truly phase perfect slope is the 24 db slope. But that's only because the shift due to the crossover is 360 degrees. However, now when we add in distance offsets, the 24 db phase perfect is probably the worst slope we can use, because since we're going from 0 phase shift, there's only one way we can go and that's up, until 720 degrees. So, again, a 90 degree phase shift can be used to combat driver offsets, and that's essentiall 6 db and 18 db slopes.

Does your head hurt? Mine sure as hell does. Wait till I get into the phase shifts in distance for particular frequencies. You'll want to stab yourself in the face.
 

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Discussion Starter · #4 ·
Does your head hurt? Mine sure as hell does. Wait till I get into the phase shifts in distance for particular frequencies. You'll want to stab yourself in the face.

:)

It does hurt. I spent 3 hrs attempting to fix phase issues. :mean:

I need to learn more to better use my in car time. Let me see if I can digest what you said with some time and a couple re reads.
 

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Discussion Starter · #5 ·
I give up on car audio completely after reading this tread. Thanks, thanks A LOT..... :(
:laugh::laugh::laugh:

I feel like that everyday..lol

But the one moment when it all comes together, maybe seconds even, it revitalizing my desire
 

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But the one moment when it all comes together, maybe seconds even, it revitalizing my desire
Yessir. I lactate.

Seriously though, it's a ***** to work phase out and I've spent hours trying to listen and feel it as well. IMHO, you're simply limited to the car and your clusterfuck will only be so optimal. If you're Mark E or some of these dudes that can get your path lengths .000001" or something crazy like that, then I hate you. lol...:)
 

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Even beyond path length differences, the distances between the drivers themselves can really put a hurting on things...
 
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