Free-air midbass

ECM

Member
2004-07-19 3:31 pm
Dubai
I bought a 1996 honda civic sedan and am thinking about installing an audio system in it.

My question is about the midbass drivers. My plan is to install a 6.5" component set up front (Kicker R6 Resolution). The rear parcel shelf has 6X9 openings in which I want to install some Kicker Freeair 6.5" speakers using MDF adapter rings.

However, I also plan on installing a sub in the trunk. Since the midbass drivers are free air, I will need to seal off the trunk, but if I do that, then my sub will suffer.

What is the best way to implement this?
 
If it is possible build some small housings for the mid range drivers. Youc an achive that by using MDF sheets or resin and mats or some fine fence. Also use a high - pass filter for the mid range driver or an amplifier with a built in crossover network. Most of the times the mid range systems do not have a high pass filter in the stock filter-assembly.
 

ECM

Member
2004-07-19 3:31 pm
Dubai
Yes, I thought about building some sort of enclosures for them since Kicker also recommends ported enclosures.

Since I also have a 4" component set, I thought about putting the 6.5" in the doors and kick mounting the 4" set. There isn't too much room in the kicks though.

Maybe a 6.5" in the doors and a HLCD under the dash. Maybe I can sell off some of my audio stash and pick up some horns.
 

ECM

Member
2004-07-19 3:31 pm
Dubai
Why didn't I think of that!

The rear doors do not contain speakers, but I'll take a look under the dash this afternoon. I also have an 8" square solobaric. It would be nice to stuff that sucker under the passenger side dash.

BTW, I received two 225 boards in the mail today.
 
an 8" solo upfront would be awesome man, for midbass it wouldnt require much airspace either.

you only get the bare boards? no heatsink? heck maybe you can mount both of them in that spare 2150sx heatsink....the rca ends may stick out though. :xeye:

mounting the components in the kicks is what id do if you have time...imaging is alot better and the stage moves forward nicely.

an easy way to do it is to use 6"- 8" pvc and cut them at an angle (for kicks), with the speakers mounted in the round part not the slanted part.... you could even use the pvc for the midbass enclosures.

'sometimes' you can use the grill ring and epoxy it to the pvc and just mount the speaker....
 

jol50

Member
2007-11-08 2:14 am
Eva said:
Don't use rear speakers, they spoil any chance of stereo imaging.
Everyone says that but I can't get enough midbass out of my front doors, and that is really the only place in this little car to mount mids. With rear doors it fills in better and stage is still forward with them dialed back. Now I am beating the front stage and it can't get it on. It does need more deadening in the front doors that would help, but I don't think enough.

I had junk in back and one blew so I turned them off, and it is suffering without them. They are same distance to my head as fronts, and door panel is such that they aim low and little treble comes to front from them. I'm really thinking of hacking in some larger spare 6x9 I have for more upper bass. Also I can turn them up and it sounds way better when listening outside the car. They are only about 1-1.5' behind my head in the car and mounted low.

For that car IMO if you run rears use 6x9 for sure to get more midbass, put a sturdy enclosure over them that will stop the sub sounds/pressure from beating on them. In old large cars with open/unsealed trunks sometimes you can get away with it, the 6x9 will not move with the bass if you test for it.
 

shagone

Member
2007-04-11 9:42 pm
ECM said:
I bought a 1996 honda civic sedan and am thinking about installing an audio system in it.

My question is about the midbass drivers. My plan is to install a 6.5" component set up front (Kicker R6 Resolution). The rear parcel shelf has 6X9 openings in which I want to install some Kicker Freeair 6.5" speakers using MDF adapter rings.

However, I also plan on installing a sub in the trunk. Since the midbass drivers are free air, I will need to seal off the trunk, but if I do that, then my sub will suffer.

What is the best way to implement this?


read this thread about issues in the same type of car:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=116917&perpage=25&pagenumber=1
 

jol50

Member
2007-11-08 2:14 am
I didn't think of it but if you don't need huge bass and want SQ, you could run free air (IB) subs on the rear deck. 6x9, 8, or best 10" subs in the deck usually sound great. With a good set of comps properly installed in front you should have nice sound. You can't knock over buildings with one set of small subs IB, but they can produce great sound and get low with the most trunk space left. If you have reason to do exactly what you are asking, then I would say put an enclosure over the back of the mids in the deck, and see if you can remove some sound insulation in the seat back or vent it. That seems to be an issue with these cars stopping the sub from getting through.
 
jol50 said:

Everyone says that but I can't get enough midbass out of my front doors, and that is really the only place in this little car to mount mids.

Then consider using an advanced DSP headunit (like the modern Alpines) to apply low-pass to the rear speakers so that they only produce midbass and bass, and to apply suitable delays to everything so that the mid/low frequencies coming from front and rear speakers are in phase and add up in the listening position.

Distance translates into a phase shift proportional to frequency (and to distance), that's why speakers at different distances from you don't sum properly but sometimes cancel. This also happens at midbass frequencies between left and right channels since one is 50cm to 100cm further than the other.
 

jol50

Member
2007-11-08 2:14 am
I'm thinking about the Pioneer 880, I think it will do what I need and many recommend it. Not sure I want to put more coin into a HU than that. I've had plenty of systems that sounded great with out DSP, but getting them that way takes time. One thing I don't like is not being able to adjust stuff while on the move like I can with my current crossover/EQ.
 

ECM

Member
2004-07-19 3:31 pm
Dubai
I didn't get a chance to look under the dash yesterday, but I will today. My civic a right hand drive to the gas pedal is to the outside of the vehicle and that gets in the way of building some kick panels.

I'm kicking myself right now because I had some free air kicker 6X9's that I sold to a friend about a week before I decided to buy the civic. I do have two pair of 6.5" kicker freeairs I thought about mounting directly behind the rear seat for a total of 4 free air "subs."

Unfortunately, I don't have any other free air speakers. I only have one sqaure 8" solo and 4 kicker competition 12" c12c.

I never intended to put anything but midbass in the rear deck as I'm not a big fan of "sound from the rear." I have a few crossovers as well so I can make sure the rear speakers put out only midbass.

Another idea I had in my sleep is to seal off the entire trunk and mount a pair of 6.5's in the deck. Those will run free air. Then, mount a pair of 12's directly behind the rear seat in their own sealed box. Essentially, I would be doing the opposite of my first idea which is to seal off the subs and run the 6.5's free air. Basically, they would both be firing into the cabin, but the sealed box would keep the 12's from interfering with the 6.5's.
 

ECM

Member
2004-07-19 3:31 pm
Dubai
Well, I took a look under the dash on both sides and there is zero room to stuff a midbass driver down there.

My Kicker R6 components don't fit in the front doors either! I think they are 6.75 inch speakers, not a true 6.5 inch. I may just purchase some 5.25 inch mids off ebay or something. I'm looking to do a simple install and don't want to fab up any kicks.

I think I may have to give up on the midbass drivers. A single 8" sub in the trunk with a 5.25 inch component set up front is what I'll probably end up doing.

thanks for all the tips guys.
 

jol50

Member
2007-11-08 2:14 am
My .02

If you don't care about big bass and also want midbass, I recommend you try a pair of 8 or better 10s in the rear deck IB....or whatever you can fit. You can adjust the crossover to cover about any range you want. A parametric will really help you. You can get some bass that is not directional, and if you can get the slope right have it trail off into midbass so it supports the front stage in a not so noticeable fashion. I set up a ton of old school systems this way, it can work well. Also with the rear deck straight behind you it is not as directional unless you turn your head. The 10 and 8 subs usually peak higher than typical crossover of 50-80Hz, then they will try to play above that which gives the trailing off midbass.

A parametric will make it easy, but you may have to swap or fiddle with drivers/crossovers to get it right without. A cheaper efficient paper sub can work well for this if you are not wanting big power, used to run 2x75rms amps all the time on 10s and they could put out a lot for music listening. One of the best was the cheap $15 paper pyramid 10", but it is blue now and may have been changed some. I'm thinking of trying them again. Even if you have a factory opening/grill, you can go a little larger and just mount the sub on a 3/4" plate under it. If it restricts it a little it just makes some aperiodic for it. I used to cut a slot and mount two 10s that way in old GM, like the old monte and cutlass with the straight rear window. Worked great. I would run 10" subs right into the 6x9 holes with a plate. Like I said if you drive them hard you may have issues doing that, but otherwise not. They don't need to have big xmax either. A 10 will put out more without having to drive it hard.
 

ECM

Member
2004-07-19 3:31 pm
Dubai
jol50, that's a good idea. I'm still throwing around some ideas before I jump into it. The weather is still pretty bad, so I'm not in any big hurry to get the audio installed since I don't have a garage.

I may have to start lurking around ebay to find what I need. The only free air speakers I have are 4 kicker 6.5". The 8 inch kicker is a solobaric and my 4 12's are comp, not free air.

I really like the idea of some IB subs. That way I keep my trunk and I won't have to build a box, just seal up the trunk.
 

jol50

Member
2007-11-08 2:14 am
IB=Infinite Baffle. Same as free air, there is no box but the front and rear must be separated.

They say use a mid-Q driver for IB or higher. I think the ones I have are .49 Qts and they work well. If the subs are good for a ported box then often they will do free air. I would not use under maybe .40, unless it was a really HD high power sub. Some of the large 15" they are using IB in HT (home theater) even with a low Q....but they are very beefy units. The problem is at higher power they can't center well without a box helping.