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Discussion Starter · #1 ·
Hey guys. Here is what I need help with. Since rear is just mainly for fill would it be better to have just a mid bass driver in the back doors or should I just stick with a coaxial speaker. Any help would be great. Thank you and god bless
 

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Just midbass. High frequencies behind you need to be handled with care. If you have a DSP to do a proper rear fill setup, and the knowledge and interest in tuning, then the answer may be different. However, for most circumstances you won't want high frequencies behind you.
 

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Discussion Starter · #3 ·
Just midbass. High frequencies behind you need to be handled with care. If you have a DSP to do a proper rear fill setup, and the knowledge and interest in tuning, then the answer may be different. However, for most circumstances you won't want high frequencies behind you.
That’s kind of what I was thinking but didn’t know for sure. I just wondered if it would sound weird with no high’s coming from back there
 

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Ideally rear fill is mounted up high and with a band pass of 300-3500hz. Some prefer rear fill to be stereo but again mounted higher is better. Now as far as midbass in rear doors some have used it as a midbass and ran 80-300hz and t/a to the driver in single seat tune. This of course opens up other problems. Just some things to think about. Dave
 
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Discussion Starter · #5 ·
Ideally rear fill is mounted up high and with a band pass of 300-3500hz. Some prefer rear fill to be stereo but again mounted higher is better. Now as far as midbass in rear doors some have used it as a midbass and ran 80-300hz and t/a to the driver in single seat tune. This of course opens up other problems. Just some things to think about. Dave
What other problems? I’m not an spl guy. At 48 I just want the best sounding system I can get. Just pure sound
 

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Phase issues with the front midbass and can pull the stage to the rear primarily.
 
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Oh, I don’t want that. I want the stage to front and center on the dash. Looks like I will be staying with coaxial for the rears
High frequencies are going to pull the stage back much more than anything. If you want a good soundstage that is up front and center, do not use a coax, use only midbass. If you have a DSP to get the rear midbass aligned with the front, even better, but if you don't have DSP, then a coax is going to be much more problematic than just using midbass speakers.
 

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Discussion Starter · #11 ·
High frequencies are going to pull the stage back much more than anything. If you want a good soundstage that is up front and center, do not use a coax, use only midbass. If you have a DSP to get the rear midbass aligned with the front, even better, but if you don't have DSP, then a coax is going to be much more problematic than just using midbass speakers.
Ok. Thank you
 

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Ok. Thank you
I can't say that I agree completely with gijoe in regards to how to implement the rear speaker locations in this instance.

In general, I think we can all agree to put most of your money towards the front stage component speakers, as that will ultimately determine how good your front soundstage will be (along of course with solid speaker mounting baffles/rings, thorough sound deadening treatment that seals any openings or holes in the front door's sheetmetal panels where the speakers are mounted, and of course, proper tuning with a capable DSP).

But there's absolutely nothing wrong with wanting a decent pair of coaxial speakers in the rear for when you have rear seat passengers. You can simply Fade them to a level where they aren't detrimental to the front soundstage when you don't have any rear passengers.

OR, you can use them to add Ambience and Space to the listening environment and enhance the front soundstage by using standard stereo "rear fill" where you raise the rear volume until it just starts to pull the soundstage towards the back, then add between ~12ms to ~23ms of delay to them until it shifts the soundstage forward again.

For this to work well, Andy from Audiofrog says that you really only need a HPF above ~100Hz and not a bandpass. Use a HPF at a slightly higher frequency that is appropriate if it's a smaller speaker. According to Andy, creating a bandpass by adding a LPF to reduce the high frequencies in the rear fill is not necessary or is optional.

But I sometimes apply a low order ~4-6kHz LPF or gentle shelf filter depending on the proximity/location/aiming of the rear fill speakers to the listening position. IME, at a real or live venue that has "late" or distant reflections, the higher frequencies naturally roll off a bit and lose some energy or amplitude over distance. And I usually land on a 160Hz HPF for the stereo rear fill regardless of the speaker size as they'll never be required to play at any significant volume when used in this scenario.

Andy at Audiofrog has suggested and prefers this "standard stereo rear fill" technique rather than using what we refer to as "Differential Rear Fill" which can produce some very odd effects on some music depending on what techniques were used during the mixing process.

Personally, I wouldn't try to implement the rear speaker locations to try to enhance the midbass response of the front stage. Instead, I would use the subwoofer to do this as per ErinH's YouTube video titled, "Using your Subwoofer to Improve your Midbass" on his Erin's Audio Corner YouTube channel.
 

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Discussion Starter · #13 ·
I can't say that I agree completely with gijoe in regards to how to implement the rear speaker locations in this instance.

In general, I think we can all agree to put most of your money towards the front stage component speakers, as that will ultimately determine how good your front soundstage will be (along of course with solid speaker mounting baffles/rings, thorough sound deadening treatment that seals any openings or holes in the front door's sheetmetal panels where the speakers are mounted, and of course, proper tuning with a capable DSP).

But there's absolutely nothing wrong with wanting a decent pair of coaxial speakers in the rear for when you have rear seat passengers. You can simply Fade them to a level where they aren't detrimental to the front soundstage when you don't have any rear passengers.

OR, you can use them to add Ambience and Space to the listening environment and enhance the front soundstage by using standard stereo "rear fill" where you raise the rear volume until it just starts to pull the soundstage towards the back, then add between ~12ms to ~23ms of to delay to them until it shifts the soundstage forward again.

For this to work well, Andy says that you really only need a HPF above ~100Hz (or a HPF at a slightly higher frequency that is appropriate if it's a smaller speaker) and not a bandpass. According to Andy, a LPF to reduce the high frequencies in the rear fill is not necessary or is optional. But I sometimes apply a low order ~4-6kHz LPF or gentle shelf filter depending on the proximity/location/aiming of the rear fill speakers to the listening position. IME, at a real or live venue that has "late" or distant reflections, the higher frequencies naturally roll off a bit and lose energy or amplitude over distance. And I usually land on a 160Hz HPF for the stereo rear fill.

Andy at Audiofrog has suggested and prefers this "standard stereo rear fill" technique rather than using what we refer to as "Differential Rear Fill" which can produce some very odd effects on some music (depending on what techniques were used during the mixing process).

Personally, I wouldn't try to implement the rear speaker locations to try to enhance the midbass response of the front stage. Instead, I would use the subwoofer to do this as per ErinH's YouTube video titled, "Using your Subwoofer to Improve your Midbass" on his Erin's Audio Corner YouTube channel.
Well, you lost me. Ha! But that’s ok. From what I get it sounds like it would be ok to run a 6x9 coaxial for the rear
 

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Did op ever detail what the system is other than saying what subs will be run? I would spend most of my time on the front stage and tune. I wouldn’t worry about rears or rear midbass unless the car lacks space up front to run midbass. Examples like the front only can accommodate at 4 inch speaker but I have provisions for a 6.5 or 8 inch in the rear. I haven’t personally run rear fill in years and the last time I did it was a band pass mid with no tweeter in the back.
 

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Several opinions on this and most are notable. Personally, I've kept it simple in the situations I've used rears... matching coaxials (not necessary, just a habit), hi passed similar to the front, a bit of attenuation and delay added. Done this with a simple deck DSP, and Helix DSP. Seemed to do fine for me.

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I can't say that I agree completely with gijoe in regards to how to implement the rear speaker locations in this instance.

OR, you can use them to add Ambience and Space to the listening environment and enhance the front soundstage by using standard stereo "rear fill" where you raise the rear volume until it just starts to pull the soundstage towards the back, then add between ~12ms to ~23ms of delay to them until it shifts the soundstage forward again.
I get the impression that OP does NOT have DSP, which is what is motivating the responses I've given.

If OP has DSP, and the time and interest in tuning rear fill into the equation, then my advice would change.

Without DSP there's no way I would add high frequencies behind me if a good soundstage was the goal.
 

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Discussion Starter · #17 ·
I get the impression that OP does NOT have DSP, which is what is motivating the responses I've given.

If OP has DSP, and the time and interest in tuning rear fill into the equation, then my advice would change.

Without DSP there's no way I would add high frequencies behind me if a good soundstage was the goal.
Sorry guys. Should have said this first. Here is my car and system
2007 dodge caliber
Pioneer Ddx-396
Audiocontrol matrix plus
Cadence qrs6k3
Nvx vsp69
Fronts and rears then go to pioneer gym-dx874
Sub comes out of matrix plus and goes to audiocontrol epicenter then to pioneer gym-dx971
Skar sdr-3x8d2
All wiring is nvx x-series
Complete nvx sound deadening
I eventually want to get a dsp and will either go with audiocontrol dm-608 or hertz h8dsp
 
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