# Location on mid-bass drivers



## bigguy2010 (May 18, 2010)

Hey all,

I'm finally at the point were I can start planning out my mid-bass install.

I'll be using the following:

Patrick's Unity Horns 
Mid-bass - ???
JL Audio 12W7
JL Audio 500/5
Pioneer DEH-P800PRS

All in a 2007 Ford Focus ZX5.

I want to put the mid-basses in the kicks for a few reasons. First being the imaging that can be achieved with having them in this particular orientation. Also the depth they'll have in that location. Lastly, I don't really want to deal with buzzes and noises coming from a 8" mid-bass in the doors. 

The factory speaker location in the doors, isn't very close to any boundaries, it's somewhat in the middle of the door. So I'd have to do some major surgery to get them down in the bottom corner of the door. 

Can anyone help me out in terms of which way is best? I don't have a driver picked out so this may be a problem.


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## CDT FAN (Jul 25, 2012)

http://www.diymobileaudio.com/forum...ussion/150134-crazy-imaging-stock-system.html

In this thread, Patrick makes a good case for mounting your mid-bass at 180 degrees. Since you already have a headstart, you should try it and see how well it works.


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## Eric Stevens (Dec 29, 2007)

The best way is the way that you can do it according to your fabrication skills.

I recommend doing some exploratory inspection to the KP area and seeing what you have to work with. You would be better off with a 6.5" done right than an 8" done wrong.

You want to vent the rear wave into the structure of the car if its large enough and if not then you want to vent to the outside in some manner that wont act like a port.

Mounting them flat on the KP will work well as you are well within the power response of the driver. You want them mounted to a solid baffle that is possibly decoupled from the surrounding metal so it wont transfer as much energy into the metal surrounding the mounting area. 

Eric


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## thehatedguy (May 4, 2007)

Which Unity horns are you using with what midrange drivers on them?


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## bigguy2010 (May 18, 2010)

CDT FAN said:


> http://www.diymobileaudio.com/forum...ussion/150134-crazy-imaging-stock-system.html
> 
> In this thread, Patrick makes a good case for mounting your mid-bass at 180 degrees. Since you already have a headstart, you should try it and see how well it works.


I will give this a good read-through. Thanks!


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## bigguy2010 (May 18, 2010)

Eric Stevens said:


> The best way is the way that you can do it according to your fabrication skills.
> 
> I recommend doing some exploratory inspection to the KP area and seeing what you have to work with. You would be better off with a 6.5" done right than an 8" done wrong.
> 
> ...


Eric,

My fabrication skills are fairly good, IMO. I'm not an installer by trade but I've been in the hobby for over 10 years. This isn't as long as others, but I have a good handle on what it takes to build these.

I've read on other posts of yours about venting into a pillar or similar area, which I have space to do. There's a nice ~3" x 5" rectangular hole in the pillar where a harness bracket sits. This can be removed, the harness can be lengthened or the bracket can be pulled out and laid next to the hole. I've already had this vehicle entirely torn down and put back together, so I know what's there to work with. I would rather find a way to utilize this space, than cutting a hole to vent to the outside.

Do you mean mounting them on the same plain as the KP's? Basically firing into the center console, similar orientation to most door speakers? I've studied a LOT on decoupling, so this will definitely be part of the finishing process. This is also why I didn't want them in the doors. My leg lays right on the door panel and so does the seat, whether someones in it or not. I understand how we perceive that transferred vibration from the door to panel into our bodies.

Thanks for all the help guys!


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## bigguy2010 (May 18, 2010)

thehatedguy said:


> Which Unity horns are you using with what midrange drivers on them?


They're these ones:

http://www.diymobileaudio.com/forum...ion/60146-creating-perfect-soundstage-11.html

I'm using the same 2" paper cone mids, Patrick used from PE, along with the Celestion CDX1-1425's.


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## Eric Stevens (Dec 29, 2007)

bigguy2010 said:


> Eric,
> 
> My fabrication skills are fairly good, IMO. I'm not an installer by trade but I've been in the hobby for over 10 years. This isn't as long as others, but I have a good handle on what it takes to build these.
> 
> ...


Yes I would recommend on same plane as the KP as long as the low pass crossover is no higher than 1500 Hz, and lower than 1000Hz is even better.

I like to create the front baffle fiberglassed directly to the metal of the car and then multi layer the mounting area for the driver to decouple it. As I build it I will run impedance curve on the driver and enclosure and use fiberglass stuffing to damp the rear wave and maybe some foam to prevent rear reflections. I shoot for a low Q system and shoot to damp the impedance peak as much as possible without raising the lowest points of the impedance curve. 

Eric


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## bigguy2010 (May 18, 2010)

Eric Stevens said:


> Yes I would recommend on same plane as the KP as long as the low pass crossover is no higher than 1500 Hz, and lower than 1000Hz is even better.
> 
> I like to create the front baffle fiberglassed directly to the metal of the car and then multi layer the mounting area for the driver to decouple it. As I build it I will run impedance curve on the driver and enclosure and use fiberglass stuffing to damp the rear wave and maybe some foam to prevent rear reflections. I shoot for a low Q system and shoot to damp the impedance peak as much as possible without raising the lowest points of the impedance curve.
> 
> Eric


My LPF on the HU will be set as low as it will go, I think it's ~1k. I want to set it lower, but that's the lowest the deck allows. So the mid-basses will be playing 80-1000 hz, then the horns up from there obviously.

Thanks for the tips on getting the MB dialed in. I just don't have a means of measuring it. The only test equipment I own is a DMM.

So do you guys have any recommendations on drivers?


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## minbari (Mar 3, 2011)

this and a cell phone.

Dayton Audio iMM-6 iDevice Calibrated Microphone  390-810

might not be studio quality, but it does work pretty well.


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## bigguy2010 (May 18, 2010)

minbari said:


> this and a cell phone.
> 
> Dayton Audio iMM-6 iDevice Calibrated Microphone* 390-810
> 
> might not be studio quality, but it does work pretty well.



Nice! I didn't know such a thing existed. I figured I had to buy some software and mic. I'll pick one of these up for sure!


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## Eric Stevens (Dec 29, 2007)

bigguy2010 said:


> My LPF on the HU will be set as low as it will go, I think it's ~1k. I want to set it lower, but that's the lowest the deck allows. So the mid-basses will be playing 80-1000 hz, then the horns up from there obviously.
> 
> Thanks for the tips on getting the MB dialed in. I just don't have a means of measuring it. The only test equipment I own is a DMM.
> 
> So do you guys have any recommendations on drivers?


All you need is a true RMS DMM to measure impedance with a couple of resistors using a test CD with tones on it or a tone generator. 

I am doint this by memory so I appolgize if I leave out something important.

Put a 50 ohm 5 or 10 watt resistor in series on the positive speaker wire and disconnect the speaker and hook up a 10 ohm 5 or 10 watt resistor in place of the speaker (disconnect speaker and connect resistor). Set the volume level of the source feeding the amp so you get 1 volt AC measured accross the 10 ohm resistor with a 50 Hz tone. 

To measure the speaker impedance reconnect the speaker in place of the 10 ohm resistor and read the voltage when playing tones from 20 Hz to 200 Hz at equally spaced intervals of 5 Hz or so. You can graph this on a sheet of graph paper or load in excel and graph it.

So 1 volt is equal to 10 ohms impedance and .5 volts would be 5 ohms and 2 volts would be 20 ohms.

Eric


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## Patrick Bateman (Sep 11, 2006)

minbari said:


> this and a cell phone.
> 
> Dayton Audio iMM-6 iDevice Calibrated Microphone* 390-810
> 
> might not be studio quality, but it does work pretty well.


Even the built in mic on a smartphone is pretty good! The main prob with phones is that the phone will sometimes highpass the signal. Basically makes it useless for measuring below 100hz.


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## Patrick Bateman (Sep 11, 2006)

bigguy2010 said:


> They're these ones:
> 
> http://www.diymobileaudio.com/forum...ion/60146-creating-perfect-soundstage-11.html
> 
> I'm using the same 2" paper cone mids, Patrick used from PE, along with the Celestion CDX1-1425's.


Rad! That worked well. If I did it again I'd do the filtering with minidsp. (Passive works, but is a huge time killer)

I just bought a Mazda6 and I'll likely do some underdash HLCDs with 8" B&C midbass and IB subs.


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## bigguy2010 (May 18, 2010)

Patrick Bateman said:


> Rad! That worked well. If I did it again I'd do the filtering with minidsp. (Passive works, but is a huge time killer)
> 
> I just bought a Mazda6 and I'll likely do some underdash HLCDs with 8" B&C midbass and IB subs.


Yeah I still haven't build them. I'm getting the horn pieces cut at work on the water jet and hope to have them started in the next month or so.


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## bigguy2010 (May 18, 2010)

Patrick Bateman said:


> Even the built in mic on a smartphone is pretty good! The main prob with phones is that the phone will sometimes highpass the signal. Basically makes it useless for measuring below 100hz.


What app are you guys using for this? I'll just try out my iPhone 4 first and go from there.


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