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Werewolf, Lycan, Glasswolf, etc. was one of the most significant people in the early years of this website. His knowledge was incredibly valuable. He pretty much introduced us all to differential rear fill, among other things.

I wouldn't be concerned about having localization issues from the rear midbass, I think you can keep that under control. My concern is that if you tie each side in parallel then you cannot TA them independently, and since phase is so important in those frequencies I think you'll end up with a pretty jagged frequency response across your midbass passband. I think that unless you can process them all independantly that the interference that you'll have from the 4 midbasses will screw up the frequency response so badly that having the extra midbass output won't be worth it.

Even if the midbass are all within the "cone of confusion" I suspect the phase problems that you'll have will make the rear midbass more of a step backwards than of forwards.
 

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Unfortunately I need to keep reading the thread seafish referenced to figure out at what frequency Intra-aural Intesity Difference starts to disappear. I used to know this years ago but have recently filled tha region of my brain with other info like Binge watching Tiger King :). I thought the threshold was about 200Hz. This is too low for my 3-1/2" midranges to take over. I don't have an extra set of channels to try what SQ_Blaze is suggesting.

I'll be using a Helix V Eight so I am limited on channels. I wanted the V Twelve but at nearly 2x the cost of the V Eight I didn't see enough of a cost to benefit advantage.

Ge0
Yes, 200 sounds about right. I notice very little below 400... But 500 starts to become a problem...
 

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Do you sit in the middle of the cabin equidistant from all the speakers? If so, do it!

I had a Sony mex-n5000bt with the "rear bass enhancer" option which was an LPF on the rear doors, you couldn't set the LPF above 120hz unfortunately, but you could set a pretty shallow slope. It seemed to work pretty good at smoothing response and getting a bit more SPL. Time alignment definetly matters, you're not gonna wanna run the front and rear drivers in series/parallel in a typical setup.
 

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Ge0, below is from the Hybrid Audio Technology speaker manuals where they talk about install considerations. They define IID (dominates above 2 kHz) and ITD (dominates below 500 Hz):




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Discussion Starter #25
Ge0, below is from the Hybrid Audio Technology speaker manuals where they talk about install considerations. They define IID (dominates above 2 kHz) and ITD (dominates below 500 Hz):




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Yep. I had it backwards. My mind was numb from reading.

Ge0
 

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Discussion Starter #26
you're not gonna wanna run the front and rear drivers in series/parallel in a typical setup.
That is exactly what I was planning on doing. But, crossing them over at 350Hz starts to encroach on the region where ITD is noticeable. I don't want to ruin my sound stage to gain 3db of midbass.

Ge0
 

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Discussion Starter #27
Werewolf, Lycan, Glasswolf, etc. was one of the most significant people in the early years of this website. His knowledge was incredibly valuable. He pretty much introduced us all to differential rear fill, among other things.
Yep. Including me. I haven't ran a system without L-R rear fill since 2008. It works wonders when dialed in right.

Also, I'm scrapping my idea of rear midbass since i will not have independent control over those channels. They would be in parallel to the fronts.

Ge0
 
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