# Midbass in rear doors?



## Offroader5 (Apr 8, 2011)

I'm putting together my system and wondering whether it's a good idea to use the rear doors as a midbass location. Not sure if it would screw with imaging or not.

My 2003 4Runner has 6x9 openings in the front door (with high tweet) & 6.5 rear door openings. My plans for the front are to either install a nice set of 6.5 components with the tweet & woofer split...or keep the tweet with the woofer low, and use the OEM high tweet mount for a small full range.

My thoughts are that these 6.5's in the front won't be enough midbass (I like rock and like to hear the kick of the drums/snare) so I was thinking of using the rear doors for a 6.5 stand-alone woofer. The rear door speaker is about 6" behind the front seat headrests and of course far below listening level, hence why I was concerned that they would interfere with the front stage.

The ID CX62 v.2 were the one's I was thinking of for both the front & rear woofers. I'll have about 200 clean watts for each door.

So, does this sound like a good plan or will the rear woofers work against the front?


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## trumpet (Nov 14, 2010)

The main fear of using a rear door midbass is pulling the sound behind you. Some people have done rear door midbasses to good effect, so it is plausible. You'll need to seal up holes and dampen the doors just the same as the front doors. I suggest you start with a good 6x9 2-way component set for up front, and then if you can't get enough midbass move on to the rear doors to supplement the 6x9s. If you want to take a look at a nice set the CDT Audio HD-690-COM is worth a hard look.


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## avanti1960 (Sep 24, 2011)

FWIW- 
in my new vehicle aftermarket upgrade (the first time around) I ignored the rear doors in my 4-door small SUV. I ran a 4-channel amp, (2) to new components in the front doors and bridged (2) for the sub in the cargo area. 
Unfortunately ignoring (not amplifying) the rear door speakers was a huge mistake in my vehicle because there was a huge hole in the midbass sound- despite sealing and deadening the front doors. the system sounded thin and tinney. 
apparently the acoustics of my vehicle rely on the mid-bass output of the rear door speakers- they are much better enclosures for bass than the front doors are. 
my solution (after much more cost) was to upgrade to a 5 channel amp and I am happy with the results. 

with people putting multiple subs in a vehicle, why wouldn't it make sense to utilize the existing midbass enclosures of the rear doors too? 

I do get some sound stage localization issues but I have component tweeters in the rear doors too (I care about the rear passengers I guess!) But it is not too big of a deal. My front tweeters are bright enough to provide a nice forward stage.


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## Offroader5 (Apr 8, 2011)

I will be running a 5 channel amp myself. The option of putting midbass in the rear is a factor to help decide how I am going to run the front 4 channels. If I don't run rear midbass, I will run the front doors more as an active front stage using all 4 channels vs. only two channels going to the front and the rear channels dedicated to the rear midbass.

What I'm trying to avoid happening is if I go without the rear midbass, and run all 4 front channels to the front doors, and then be lacking in midbass. If so, then I have to rework the front door channels so I can run an added set of midbass in the rear. I don't want to have multiple amps which is why I chose to go 5 channel. I also don't want to have to rework/build new front door panels just so I can install another set of woofers.

I'm trying to avoid going with full custom, multi-amp system. I just want a good sounding system with one sub, one amp, and good components in the doors.




avanti1960 said:


> FWIW-
> in my new vehicle aftermarket upgrade (the first time around) I ignored the rear doors in my 4-door small SUV. I ran a 4-channel amp, (2) to new components in the front doors and bridged (2) for the sub in the cargo area.
> Unfortunately ignoring (not amplifying) the rear door speakers was a huge mistake in my vehicle because there was a huge hole in the midbass sound- despite sealing and deadening the front doors. the system sounded thin and tinney.
> apparently the acoustics of my vehicle rely on the mid-bass output of the rear door speakers- they are much better enclosures for bass than the front doors are.
> ...


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## avanti1960 (Sep 24, 2011)

at least you can run new wires if you need midbass in the rear doors- i had to buy a whole new amp too! 

but seriously, is your stock system running now? try fading just to the front to see how i sounds. then fade to the rear (only). You may notice that the rear doors provide much more bass than the front ones- I wish I had done this test before I decided to eliminate the rear speakers. 

its also doubtful that the subwoofer can compensate if you decide to run active on the fronts and kill the rears. 

i tried that too before I bit the bullet on the rear speakers and 5-channel amp- I set the low pass relatively high for a sub to fill the hole~ around 125hz or so. The sub did not like that and lost all of its tightness and SQ. So I was left with really deep lows, a big gaping hole from 80 hz to 200 hz that left me with a thin harsh soundstage that could not be compensated for with EQ. 
good luck!


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## adrenalinejunkie (Oct 17, 2010)

http://www.diymobileaudio.com/forum...-advanced/74088-midbass-arrays-revisited.html


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## denetnz (Jul 31, 2009)

avanti1960 said:


> its also doubtful that the subwoofer can compensate if you decide to run active on the fronts and kill the rears.
> 
> i tried that too before I bit the bullet on the rear speakers and 5-channel amp- I set the low pass relatively high for a sub to fill the hole~ around 125hz or so. The sub did not like that and lost all of its tightness and SQ. So I was left with really deep lows, a big gaping hole from 80 hz to 200 hz that left me with a thin harsh soundstage that could not be compensated for with EQ.
> good luck!


Sorry, I'd have to dissagree here. Unless you are running a very large or a very non SQ sub, I see no reason whatsoever to use 2 piddly 6.5" drivers in rattly, leaky doors for midbass rather than a decent sub, given that they are already behind you. Not to mention the TA issues from 5 bass sources which can only be TA'd properly for one listener. 

Any decent SQ sub should easily run to 100Hz unless it's in a horribly tuned ported box. After 100Hz, any decent 6.5" should easily keep up.

Alternatively, just buy some killer 7" (i.e. Scan Illumnator 18WU4147), treat your doors properly and never ever worry about a shortage of midbass again. (and get killer midrange at the same time too!). I've just put mine in, and I think my eq is currently set to -8db at 50Hz! (I'm going to cross them a little higher to alleviate the need for this) I don't know if you follow the Klippel test thread, but this driver is currently the Klippel king by a long margin and I cannot say enough about how impressed I am with it. (for anyone tired of me talking about my Illuminators, I'm sorry, I don't have any SQ friends offline, so I have to tell you all here! )


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## nick650 (Feb 7, 2011)

denetnz said:


> Sorry, I'd have to dissagree here. Unless you are running a very large or a very non SQ sub, I see no reason whatsoever to use 2 piddly 6.5" drivers in rattly, leaky doors for midbass rather than a decent sub, given that they are already behind you. Not to mention the TA issues from 5 bass sources which can only be TA'd properly for one listener.
> 
> Any decent SQ sub should easily run to 100Hz unless it's in a horribly tuned ported box. After 100Hz, any decent 6.5" should easily keep up.
> 
> Alternatively, just buy some killer 7" (i.e. Scan Illumnator 18WU4147), treat your doors properly and never ever worry about a shortage of midbass again. (and get killer midrange at the same time too!). I've just put mine in, and I think my eq is currently set to -8db at 50Hz! (I'm going to cross them a little higher to alleviate the need for this) I don't know if you follow the Klippel test thread, but this driver is currently the Klippel king by a long margin and I cannot say enough about how impressed I am with it. (for anyone tired of me talking about my Illuminators, I'm sorry, I don't have any SQ friends offline, so I have to tell you all here! )


-8dB at 50Hz is a very bad idea. Try more around 70Hz at -12dB. You won't be losing out anything and will sound better/ louder.


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## denetnz (Jul 31, 2009)

nick650 said:


> -8dB at 50Hz is a very bad idea. Try more around 70Hz at -12dB. You won't be losing out anything and will sound better/ louder.


I wasn't saying my crossover was set at 50Hz, but my EQ setting at 50Hz is currently -8db to compensate for having too *much* midbass.  B.t.w, this is not your average midbass driver and 50Hz is not at all low for it. Mine is actually currently crossed at 40Hz(!) and is clean as can be. As I said, I will be revising it, but only to reduce midbass output. I understand that Erin (bikinpunk) actually runs his with no highpass at all!


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## nick650 (Feb 7, 2011)

Yes I can do that with my l6se as well but will not get the loudness I'm looking for and it further helps protect the driver for those times when you want to max things out.

NVM I read it over

What is your crossover/slope at?


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## denetnz (Jul 31, 2009)

From memory, 12db at the head deck, with a further 12db down at 30Hz on the amp (as a subsonic filter).


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## Offroader5 (Apr 8, 2011)

The sub is an 8" Alpine SWR-843D. The enclosure is being designed specifically for the 4Runner cabin and will more than likely be a TL or horn design..but not sure till I see it. The sub should get around 400-500 watts.

I hadn't looked into the Illuminators...I will have to check them out. I'd have to make new spacer rings to fit a 7", but that's no biggie. I had been looking at the Peerless SLS for the rear door and this is when I came across the ID's I mentioned in the first post.

Door treatment as well as everything else is good to go. I gutted the whole interior and deadened everything I could get to with at least one layer...sometimes two or three, there is one layer on the outer door skins (three directly behind the woofer) and a layer on the interior skin sealing all holes. I also added jute backing to anything that came off before it went back on, wrapped wires with foam/jute to keep them from rattling behind panels, added padding to the roof, and used spray deadener in some hard to reach areas.



denetnz said:


> Sorry, I'd have to disagree here. Unless you are running a very large or a very non SQ sub, I see no reason whatsoever to use 2 piddly 6.5" drivers in rattly, leaky doors for midbass rather than a decent sub, given that they are already behind you. Not to mention the TA issues from 5 bass sources which can only be TA'd properly for one listener.
> 
> Any decent SQ sub should easily run to 100Hz unless it's in a horribly tuned ported box. After 100Hz, any decent 6.5" should easily keep up.
> 
> Alternatively, just buy some killer 7" (i.e. Scan Illumnator 18WU4147), treat your doors properly and never ever worry about a shortage of midbass again. (and get killer midrange at the same time too!).


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## avanti1960 (Sep 24, 2011)

denetnz said:


> Sorry, I'd have to dissagree here. Unless you are running a very large or a very non SQ sub, I see no reason whatsoever to use 2 piddly 6.5" drivers in rattly, leaky doors for midbass rather than a decent sub, given that they are already behind you. Not to mention the TA issues from 5 bass sources which can only be TA'd properly for one listener.
> 
> Any decent SQ sub should easily run to 100Hz unless it's in a horribly tuned ported box. After 100Hz, any decent 6.5" should easily keep up.
> 
> Alternatively, just buy some killer 7" (i.e. Scan Illumnator 18WU4147), treat your doors properly and never ever worry about a shortage of midbass again. (and get killer midrange at the same time too!). I've just put mine in, and I think my eq is currently set to -8db at 50Hz! (I'm going to cross them a little higher to alleviate the need for this) I don't know if you follow the Klippel test thread, but this driver is currently the Klippel king by a long margin and I cannot say enough about how impressed I am with it. (for anyone tired of me talking about my Illuminators, I'm sorry, I don't have any SQ friends offline, so I have to tell you all here! )


--
In my vehicle (4-door small SUV) there was still a hole in the sound- weak midbass output and a horribly thin sound when the sub was not active- when I did not have the rear door speakers amplified and working with the front midbass drivers. The (2) 6.5 drivers could not fill the large interior volume. 
My vehicle was designed with this in mind- the rear doors produce much more bass than the frond doors- with identical drivers. 
TA might not be an issue- in my vehicle the rear door woofer positions are the same distance to my ears as the front door drivers- this might be worth investigating by the OP. Toyota seems to account for audio in their vehicle designs.


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## denetnz (Jul 31, 2009)

Why not just raise the sub level or raise the LPF on the sub? 

This is the obvious solution - *especially* when I read what sub you have! Why add additional drivers when you already have drivers that can do everything you need? (i.e your sub) 

The 8" Type R sub you already have is fantastic sub and also a killer midbass driver. (Please refer to the thread on this sub) Some guys are running these subs up to 300Hz as midbass in a three way! Assuming the 80-150Hz range is where you are lacking midbass, no pair of 6.5" could possibly compete with this sub in this frequncy range.

It probably goes without saying, but please also ensure that all of your speakers (including sub) are in phase, or you will have holes in your FR that are difficult to fill.


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## denetnz (Jul 31, 2009)

See link below to see what some others are doing with this sub:

http://www.diymobileaudio.com/forum...100729-alpine-swr-823d-843d-8-subwoofers.html


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## Offroader5 (Apr 8, 2011)

That's actually the thread that pushed me towards the Alpine.  The 4Runner has a OEM plastic sub enclosure in the rear quarter that was in need of a replacement driver. It's been residing there for about 3 months now (but only being powered by the weak OEM JBL amp).



denetnz said:


> See link below to see what some others are doing with this sub:
> 
> http://www.diymobileaudio.com/forum...100729-alpine-swr-823d-843d-8-subwoofers.html


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## Winterboy04 (May 13, 2010)

denetnz said:


> ...It probably goes without saying, but please also ensure that all of your speakers (including sub) are in phase, or you will have holes in your FR that are difficult to fill.


I was having a very similar issue with a total lack of midbass. I have an 07 tacoma and if your 03 4runner follows the toyota mantra ...its a tin can bass robbing machine. Now, i have too much mid-bass (easily fixable). I swapped the phase on my single 10, and the entire system came alive, it was audible, and a little irritating that it was that simple.

On a side note, i have 6.5 inch HAT comps in the front, and WAS running 6.5 inch mid bass in the rear doors. Maybe its personal opinion, but it was muddy, the sound stage was terrible, and it just sounded wrong. Before i went active and 3-way, i had the fader all the to the front because it sounded so ugly.

I agree with a lot of the guys in this post, there is no reason the 6.5" front can't produce the mid-bass necessary. The more i sound deaden, the more i hear. 

just my opinion, and opinions are like @ssholes...everyone has one.


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