# Adding a midbass into a 2 way front setup



## ta_nhra02 (Jul 20, 2009)

Hey all. How can I adapt a mid-bass in my set-up?
I am running
Tweeter/Midrange- Polk Audio MM 6.5 comps on a RF amp.
2 10" eXcelon shallow mount subwoofers on a RF amp.

How can I squeeze a midbass set-up with its own separate amp in there?


What are my options?


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## MarkZ (Dec 5, 2005)

Buy an amp and a midbass driver. I don't understand what you're asking. Are you looking for specific midbass and amplifier suggestions? Mounting locations? Tell us more.


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## ta_nhra02 (Jul 20, 2009)

All i am asking is how would I hook that up into my current system. Im using my front RCA output for the comps. and the sub-w for the sub. Do I just run another set of RCA's from the rear outputs on the deck? How do I cross that over? from 80-250hz?


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## ta_nhra02 (Jul 20, 2009)

I know I can use the amps internal crossover to not go over 250hz. But how will I get it to stop playing under 80hz?


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## azngotskills (Feb 24, 2006)

you cant depend on your amp's crossovers every time, thats why there are external processors and HU with DSP


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## m3gunner (Aug 6, 2008)

You could go with an external xover on the high end to crossover to the lower driver. Set your high pass on the midbass amp to 80 Hz and feed it with the low pass on the crossover. Run the high pass on the xover to your old high pass amp and defeat the xover. 

btw Most AudioControl xovers have a infrasonic filter that can act as a low pass filter as well...


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## ta_nhra02 (Jul 20, 2009)

Is there anyway I can make this work with my alpine cda9833 with its internal x-overs?


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## ta_nhra02 (Jul 20, 2009)

Is that something that a audiocontrol 6xs can do?


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## pionkej (Feb 29, 2008)

Everybody is giving you suggestion on how you can accomplish this, but I would like to know the "why" you are wanting this, because a 3-way system does not equal good sound quality, in fact, what I think you are asking to do would only make it worse. 

If you want a dedicated midbass, it typically goes in the doors, the midrange (which appears you are using a 6.5" polk for) go in the kicks or the dash and is aimed as on-axis as possible, and the tweets can go any number of places. You need adjustable crossover slopes, options for crossover points (what if 250hz doesn't work and you need to cross higher), and a GOOD eq to control everything at minimum. Ideally you would also have gain control per driver and t/a for each channel. 

I would suggest that you research the topic more before just jumping in.

I am telling you all of this from the information you provided (or didn't provide). I have no idea what h/u you have, what car it is going in, what kind of amps you already have (other than they are RF). It just seems you have mid-level gear from what you posted. Nothing wrong with that at all, but again, slapping a midbass in there will not likely equal better sound quality, especially since those polk's are known more for their midbass and less for their midrange ability.


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## m3gunner (Aug 6, 2008)

Good point... but he said he has an Alpine 9833.


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## ta_nhra02 (Jul 20, 2009)

Ok here goes..

Vehicle is a 2000 Ford F150 Lariat.
Headunit- Alpine cda-9833
Component amp is a RF Power T400-2
Components are Polk audio Mobile Monitor Series 6.5
Sub amp is a RF power 1000
Subs are 2 10" kenwood eXcelons
about 150lbs. of raammat in every inch of the truck... firewall, roof, doors, etc..
around 300$ in NewKonceptz wiring.
Everything installed my self.
Components are in modified beefed up kick panels on the floor.
The front doors are sitting empty and I want to play around with some midbass.
I have a RF P500-2 sitting around and I want to mess around with it.
I am wanting to know how to make this a 4 way system. I have money, im not rich but I can afford to TRY and see what happens. If I can get some help.


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## pionkej (Feb 29, 2008)

EDIT: More info added while I was typing, I will address tomorrow. Tonight, I am going to bed.


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## m3gunner (Aug 6, 2008)

In the meantime, you might want to think about *why* you'd like to add midbass drivers. Most people here would add a midrange (3 or 4" driver) to your system to increase midrange clarity before they'd add something larger than a 6.5" driver to increase the midbass.

That being said, you can tweek the settings for your 9833 to run the midbass. Run your tweeters and mids off of two channels on your 9833 through the T400. Run the midbasses bandpassed off of two channels on your 9833 through the P500 and leave your sub alone on the sub channels. You'll need to switch the 9833 to three way mode (check your manual) and figure out which outputs are which, but once you've got that done, you're set. You might not need the crossovers in your amps at all.


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## ta_nhra02 (Jul 20, 2009)

The reason I want to add midbass drivers is because I have never used them before! If I don't like them I will go back to how I was! If I do like them I will keep them! And no, I do not know anybody around with mid bass in there cars so this is on me. Also if I did I cant go and listen to someones car with a midbass setup and decide if I like it or not! No two setups are the same! I want to know HOW to do this! Not be persuaded on NOT doing this!!! This is a DIY forum isn't it? So how is a 25 year old man supposed to learn if no one wants to teach?


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## hdrugs (Sep 7, 2009)

the easiest and most basic way i recomened you is to buy a bass filter 80hz. it looks like the rca tip you plug it onto to you rca and then plug the rca into your amp. then set the amp at 250hz to bandpass 80-250


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## jets88 (May 12, 2008)

"Is there anyway I can make this work with my alpine cda9833 with its internal x-overs?" 

You wont be able to do it with that HU alone. In 3 way mode you can't cross over your highs any lower than 1khz. In 2 way mode you can't cross any higher than 200 hz. Look at page 15 here, http://akamaipix.crutchfield.com/Manuals/500/500CDA9833.PDF

So it looks like you'll need an external crossover somewhere. The easiest way to do it would be to set your HU to 3 way mode and put your MB on the midrange out and bandpass them where you want them. Then put your comps on the high out and set the HU to user and set the HPF slope to flat. Then however you'll do it, either with your amp, external crossover or even a cap, HP the comps where you want them.


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## iyamwutiam (Nov 20, 2006)

ta_nhra02 said:


> The reason I want to add midbass drivers is because I have never used them before! If I don't like them I will go back to how I was! If I do like them I will keep them! And no, I do not know anybody around with mid bass in there cars so this is on me. Also if I did I cant go and listen to someones car with a midbass setup and decide if I like it or not! No two setups are the same! I want to know HOW to do this! Not be persuaded on NOT doing this!!! This is a DIY forum isn't it? So how is a 25 year old man supposed to learn if no one wants to teach?


This site, the archives of google usenet, caraudio.com, sounddomain, etc. In certain narrow fields -you can get a plethora of verygood information -caraudio stands real tall in this. You can learn the basics at Perry's site -used to be called basiccaraudioelectronics, -plus there are a ton of sites with wonderful DOY tutorials for practically anything.

Anyway -to your question.

If you are going to put the midbass in to see what it sounds like -it's easy -it sounds like there is more midbass up front. Second-you can practically do anything in a car if you have made devotion like Jeff Smith, Scott, Gary Biggs , etc ad nauseum. These guys KNOW what they are talking about. 

The point is -it will work and can sound great. But at the end of the day -you'll develop your own sense of whats right and wrong. After that the journey really begins.

I would suggest you maximize your two way as best as possible first-while you plan out your 3 way. Xover and phase can have a positive impact on midbass in a two way -that can be pretty satisfying. Just remember -that in your search for more oomph-you may actually be getting away from "hi-Fidelity".


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## pionkej (Feb 29, 2008)

Listen, you have had multiple suggestions on HOW to do this. If you would have searched, you would have found HOW to do this. While searching, you also probably would have found why your current setup is not ideal for this. Nobody here thinks a properly set up 3-way is a bad thing, many do it. The problem is WE, the ones with experience that you are asking, are telling you that you would be better served upgrading your current gear (even if you stay 2-way) than you probably will be from adding a midbass.

My take:

Look for reviews on your polk speakers. They are midlevel pieces that DO NOT excel at midrange, but that is what you are going to be using your woofer for. You will not have Midbass/Midrange/Tweeter, you will have Midbass/Midbass playing Midrange/Tweeter.

Typically, a midrange speaker will play somewhere between 4k-8khz and the tweeter will take over from there. Your polk midbass is playing midrange frequencies up the the 2-way designed crossover point, and you won't be able to change that. Even if you could, that 6.5" speaker will begin beaming well before 4k-8khz, that is why people use 3" or 4" mids placed on-axis.

You have no tunability with the setup you are looking at. Properly setting up a 3-way system takes time and tuning. You are looking to add a midbass and hoping the two crossover points you selected are going to work....what if they don't?

My suggestions:

If you are dead set on trying it, I would get the best midbass you can afford. I would make sure it is much better than your current system. If going the raw driver route, I would suggest a Peerless SLS 8". If you buy a name brand, I would suggest either Hybrid Audio's 8", Dynaudio's 8", or Morel's 9". These options at least have you prepared to upgrade to a proper 3-way without starting all over.

You state you have 150lbs. of Raammat in your truck. That is good, it probably killed most your resonances if installed properly. However, it did not do much at stopping sound waves. That is what CCF & MLV is for. If that isn't installed, I would invest money there first. If the vehicle is quieter, your speakers don't have to be turned up as loud to hear them clearly, meaning they strain less, meaning you can gain more sound quality POTENTIALLY that way than adding a SECOND midbass like you suggest.

FINALLY--I think most of us are trying to HELP you by discouraging you. We have all made mistakes and are trying to tell you this is not the right approach. Sometimes people listen, and sometimes they want to learn for themselves. It seems you are set on it, so just follow suggestion #1 and it will be your best bet at success IMHO.


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## m3gunner (Aug 6, 2008)

What he said.-----------^


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## DaveRulz (Jun 22, 2006)

Before adding midbass speakers, I would experiment with the gear you already have. 

You already have another amplifier, you already have a 9883 which is a very competent active processor.

Toss the passives and try those comps active off of the 9883. Then go from there. I remember the first time I did that, and I was SHOCKED at how much better it sounded.


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## Steak (Mar 16, 2006)

go with peerless sls 8s in doors (or kicks)
if that is not an option, get a sub with a good midbass response and use a processor to bring it upfront.
otherwise, you are dooooomed with weak midbass forever.


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## MarkZ (Dec 5, 2005)

pionkej said:


> Listen, you have had multiple suggestions on HOW to do this. If you would have searched, you would have found HOW to do this. While searching, you also probably would have found why your current setup is not ideal for this. Nobody here thinks a properly set up 3-way is a bad thing, many do it. The problem is WE, the ones with experience that you are asking, are telling you that you would be better served upgrading your current gear (even if you stay 2-way) than you probably will be from adding a midbass.


Well, wait a second here before you throw the "WE"'s around. 

I don't think there's anything inherently wrong with adding a midbass driver to his current set (assuming he gets the crossover situation worked out). If he's lacking midbass, and trying to upgrade his system without yanking everything out, it's a perfectly reasonable approach. 

I'm also not sure which MM set he has -- I forget what the model numbers mean. I never tried the new ones, but the old ones were awesome. They predated the dB series, which was another pretty good set. Err...the old dB set, not the new ones. [Sorry, haven't followed Polk's products lately...]


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## pionkej (Feb 29, 2008)

MarkZ said:


> Well, wait a second here before you throw the "WE"'s around.
> 
> I don't think there's anything inherently wrong with adding a midbass driver to his current set (assuming he gets the crossover situation worked out). If he's lacking midbass, and trying to upgrade his system without yanking everything out, it's a perfectly reasonable approach.
> 
> I'm also not sure which MM set he has -- I forget what the model numbers mean. I never tried the new ones, but the old ones were awesome. They predated the dB series, which was another pretty good set. Err...the old dB set, not the new ones. [Sorry, haven't followed Polk's products lately...]


I threw PROBABLY in there too!  He just hasn't had a good reason other than "I want to" so I suggested there may be better alternatives that would give him an even better foundation for future builds. Sorry I was so strong with the WE phrase.


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## ta_nhra02 (Jul 20, 2009)

MM6501

High performance Car speaker

6-1/2" Diameter
$329.95 per system

Customer Rating:


5.00 (from 4 users)

Our flagship MM component system, the MM6501 is the result of 3 years of Polk research and development. The MM6501 has been designed to offer unparalleled sound quality with exceptional fit to meet virtually any application. Borrowing technology from our flagship SR Series, the MM6501 offers extraordinary performance at a price that's too good to believe.

* Dynamic Balance® Driver Technology for pure, distortion free sound.
* Neodymium is a rare earth material we use in all MM driver magnets, excluding 461p, that are about 1/10 the weight of a comparable ceramic magnet and much more powerful. The smaller magnet means the MM6501 components fit easily into more applications.
* Carbon Composite Basket based on the spokes of a wheel is lightweight, absolutely will not flex during peaks and looks great.
* Woven Glass Composite Cones feature tremendous stiffness-to mass ratio. Lower mass means faster transients and finer detail.
* Klippel Optimized Components for consistent, distortion-free sound.
* Marine Certified ensures the MM6501 is built tough to withstand the harshest environments on the water.
* Large-Diameter Voice Coil (30mm) in driver increases reliability and power handling.
* Wheel-inspired style combines with rugged durability in the MM grille.
* Multiple Mount Tweeters allow surface or flush mounting. 

RMS Power 125w 250peak
Sensitivity 94db
Freq. Res. 40Hz-25kHz
Nominal Impedance. 2.7ohms

These are the Polks I have. I really like them. I was just wanting to see how a midbass would go along with them. I have made crossovers before for home audio applications, but never car audio. That's where I was wondering if there was a crossover box that I could use like something audiocontrol makes? Does anyone make a crossover module for a 4 way system? As far as seeing my "mid price gear" maybe needing different crossover points. How about some options on products to buy? I know a thing or to about audio. I am def not a rookie in the home audio crowd. My wifey is letting me play with about 500 bucks for this. If I had all the nicest gear in the world. I would not be able to have 2 cars, a truck, nice boat, house, wife, kids and a comfortable lifestyle. Thanks for understanding.


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## ta_nhra02 (Jul 20, 2009)

I suppose another reason would be to get out in the garage and have some friends over to BS and mess around with my truck. Am I allowed to have my midbass speakers yet?


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## ixi (Jul 26, 2009)

ta_nhra02 said:


> I suppose another reason would be to get out in the garage and have some friends over to BS and mess around with my truck. Am I allowed to have my midbass speakers yet?



Sounds like a good enough reason for 90% of things in life.

I'm kind of in the same boat as you, I have a decent two way comp setup but notice the gap between my mids and my sub. I'm thinking of doing the same thing (adding an 8" mid bass in my doors) but after reading on this site for a few weeks I understand what most are saying here. My 6.5" isn't going to be a very good upper mid-range speaker no matter how I cross it over or how I aim it. So I might as well buy a 4" mid which leads to I might as well reconsider my tweeter at the same time. 

If you want a 3 way front stage you should buy 3 speakers that are up to the task. Sell your 2 way comps and start over. 

If you're looking for drunk garage time, going this route will give you endless hours of tweaking and adjusting.


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## MarkZ (Dec 5, 2005)

ixi said:


> Sounds like a good enough reason for 90% of things in life.
> 
> I'm kind of in the same boat as you, I have a decent two way comp setup but notice the gap between my mids and my sub. I'm thinking of doing the same thing (adding an 8" mid bass in my doors) but after reading on this site for a few weeks I understand what most are saying here. My 6.5" isn't going to be a very good upper mid-range speaker no matter how I cross it over or how I aim it. So I might as well buy a 4" mid which leads to I might as well reconsider my tweeter at the same time.
> 
> ...


I agree with the bolded part above. In an ideal world, you choose your drivers based on the intended application rather than trying to retrofit them. 

But... that's not to say that all 6.5"/tweeter combinations do upper midrange poorly. His Polks might. I don't know. It appears from his description that they're the new MM's, which I know nothing about. But there are tons of component sets out there that do a reasonable job at the mid-tweet interface. And there are plenty of installation ideas that can accommodate a large midrange. So if I were him, I wouldn't jump ship just yet. There's really no inherent benefit to using a 4" cone to do your midrange -- yeah, they're often designed to extend higher than their 6" counterpart, but sometimes not. Hell, my 6.5" midrange is designed to extend up to 6kHz, and I mate it with a separate midbass driver. In my case, the benefit to using a large cone driver is that it's super-sensitive, requiring only a fraction of the power to get humming (and, as a consequence, it will get louder before self-destructing).

If he likes his Polks for everything except midbass, then it makes sense to start out by just supplementing them with midbass -- either with a dedicated midbass driver, or with a single driver that handles both midbass and sub duties.


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## ixi (Jul 26, 2009)

MarkZ said:


> I agree with the bolded part above. In an ideal world, you choose your drivers based on the intended application rather than trying to retrofit them.
> 
> But... that's not to say that all 6.5"/tweeter combinations do upper midrange poorly. His Polks might. I don't know. It appears from his description that they're the new MM's, which I know nothing about. But there are tons of component sets out there that do a reasonable job at the mid-tweet interface. And there are plenty of installation ideas that can accommodate a large midrange. So if I were him, I wouldn't jump ship just yet. There's really no inherent benefit to using a 4" cone to do your midrange -- yeah, they're often designed to extend higher than their 6" counterpart, but sometimes not. Hell, my 6.5" midrange is designed to extend up to 6kHz, and I mate it with a separate midbass driver. In my case, the benefit to using a large cone driver is that it's super-sensitive, requiring only a fraction of the power to get humming (and, as a consequence, it will get louder before self-destructing).
> 
> If he likes his Polks for everything except midbass, then it makes sense to start out by just supplementing them with midbass -- either with a dedicated midbass driver, or with a single driver that handles both midbass and sub duties.


I agree. He said his comps are already in some custom kicks so that takes out the relative convenience of fitting and aiming a 4" driver vs. a 6.5" driver. In my case fitting a 6.5" driver down in the kicks isn't a viable option. So it sounds like what you need is a bandpass crossover capable of crossing lower than 80hz. Plenty of options available.

or

I don't think you can do this with the decks internal crossovers alone. In 3 way mode you could use the rear preamp out for a bandpass on the 8" mids but would need to come up with an external crossover for the bottom end of your comp mids (assuming you're using your comp's passive crossovers).


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