JL MicroSub experiment...

[andrewb70]

I am always interested in trying new things and seeing if I can improve on what I already have. I am sure that many of you are also like that and like to "tinker" even if something is not broken.

I have been thinking about how to increase the bass response inside my car. The issue of course is packaging as subs tend to be big and require relatively large enclosures to be effective. Even modern shallow subs are pretty big and require relatively large space.

Yesterday I was looking around on the JL website and I saw the 6.5" MicroSub loaded enclosure:

http://www.jlaudio.com/cp106lg-w3v3-...-systems-93300

The box is very small so I got my measuring tape out to see where I can install it inside the cabin. An easy solution would be to simply place it behind one of the seats. I may try that as an initial experiment to see how it sounds. However, I then started looking at the rear seat and the rear back cushion. I took them both out and as many of you know the frames are mostly hollow. I took some measurements and it looks like this little sub can be easily installed into the rear back cushion.

What do you guys think?

Andrew

[hifi875]

The 8 inch version is alot better. My shop installs them in a variety of vehicles from trucks to cars and suvs. I put one in my father inlaws 57 that runs off of the sub channel on a jl xd700/5. sounds really good. not a bass monster but vey nice. It is tucked up behind the back seat on the hump and hidden by custom trunk interior panels. basically has 0 footprint.

[scott_fx]

i just saw a video of a hybrid audio 6.5" sub in a t-line, it was pretty impressive

[ccreddell]

Im trying to scale down a Decware Deathbox to fit an 8" sub and fit between the seats. Then, if it works, Ill build a console around it.

[scott_fx]

http://www.youtube.com/watch?v=u8yArcObFZI

[mitch_04]

Maybe I'm mis-reading, but you plan on mounting it directly into the seat? Or notch out the seat to accommodate it, but mount it solid to the body?

My friend and I once mounted a subwoofer in his back dash and built a wood box around it to seal it. It sounded absolutely horrible. The reason being, we now know, is that the rear dash is not rigid enough to support such a thing. When the sub moves one way or the other, the dash would flex in the opposite direction. The subwoofer was not only losing SPL because the dash was countering it's every movement, it was also fighting the constant reverberations of the dash. In a way, this is what we try to get rid of, to a lesser extent, by adding sound deadener. It will stop panel vibrations which cancel out sound waves, as well as stopping rattling.

For that reason, if you want to mount it into the seat, I'd recommend having it mounted to the body and the seat covering it. Otherwise I believe it would move the seat when playing, lessening its effectiveness.

Next up, depending on how loud of a system you are trying to create, the subwoofer itself should work fine. SPL (Sound Pressure Level) is generally dictated by a few things.
1. Cone Area/Volume
2. Excursion (Amount it moves in and out)
3. Speaker Box Design
4. Power Capabilities

All other things being the same, the more cone area/volume a subwoofer has, the louder it will be. I don't have the stats in front of me, but long story short, a 15 would be louder than 2 8s because the 15 still has more area despite 2 8s being adding to a 16.

All other things being the same, more excursion will create a higher SPL since you are compression cabin air further.

AOTBTS, a ported box will be louder than a sealed since you are using both movements (forward and rearward) to create positive pressure. A sealed box will have a "tighter" response since it's creating a vacuum inside the box when it moves out, helping it return quickly relieving stress on the electrical side (magnet). Ported boxes need to be bigger to accommodate port volume and tuned correctly to have the correct timing for the "rear wave" to exit. Think ram air tuning and runner length on an engine, same concept.

AOTBTS, higher wattage will create higher SPL. If I recall correctly, to double SPL you need to increase power tenfold. It's been a while so I could be off, but it's close enough to give you an idea.

Hope some of this helps, I used to be into stereos heavily. You can buy the premade setup, or try to create your own with your choice of subwoofer and box. Creating your own will just take more knowledge on designing the enclosure and choosing the correct subwoofer for your goals.

[andrewb70]

I definitely agree that one of the biggest challenges will go to mount the box in a solid fashion. I already ordered it, and it will be here Friday. I think having it mounted inside the back of the rear seat will not be good, because of the problems with movement. I think what I am going to do is mount it against the rear decider that is between the cabin and the trunk. That divider is pretty solid and I think it will work well. The rear seat back will just cover it so it will be hidden.

As the title of this thread states, this is more experimental than anything. If it doesn't work in the GTO, I can always use it in my little truck.

I'll keep you guys posted.

Andrew

[mitch_04]

I hope it turns out OK. Keep us updated. I'm a little greedy with bass, my stereo in my attic waiting for my C10 has 3400 watts RMS just for the subwoofer, so the small subs could never do it for me. I did build a small stereo in my mom's '72 Bug, 2 12's with 150 RMS per in a smalled sealed box. Sounded great, nice and clean, but I just couldn't get it turned up enough!

[67rally]

Definitely keep us updated. I have a large sub box in with a pair of 12's in the back of my Camaro. It's pretty heavy, and I might look for a more compact/light weight solution in the future.

I have my amps mounted in the trunk to an MDF board that I attached to the trunk side of the seat divider. The interior metal side is covered with sound deadener. It really stiffens up the area. You could always use your cardboard divider as a template to cut out a piece of MDF and attach the sub boxes to that.

[andrewb70]

The goal here is to bring the bass into the cabin. I experimented with a big sealed box with a pair of 10s positioned in the trunk. It definitely hit harder than what I have now, but the box was just huge.

Making a board to go against the rear trunk divider is a good idea. I'll play around and see what I can come up with.

Another thing that I considered before ordering this box is to make a custom enclosure that would straddle the transmission crossmember. I don't have a console, so some of the box volume could be attained by having the enclosure act as an elbow rest.

Does anyone have experience with something like that?

Andrew

[Garymac69]

I attached a 10" Kicker 10TCVT104 shallow truck subwoofer with amp to the back of the rear seat frame, firing into the rear seat. It works great and takes up little room in the trunk.

Gary

[scott_fx]

The goal here is to bring the bass into the cabin. I experimented with a big sealed box with a pair of 10s positioned in the trunk. It definitely hit harder than what I have now, but the box was just huge.

Making a board to go against the rear trunk divider is a good idea. I'll play around and see what I can come up with.

Another thing that I considered before ordering this box is to make a custom enclosure that would straddle the transmission crossmember. I don't have a console, so some of the box volume could be attained by having the enclosure act as an elbow rest.

Does anyone have experience with something like that?

Andrew

Have you thought about doing an infinite baffle install? I've heard some great systems with IB 'enclosures' (i've even run two IB 15" subs in my home theater at my last house...WOW is all i have to say :D). basically you seal off the passage way from the trunk to the cabin (isolating the air in front of the woofer from the back)... thats it no box

https://www.google.com/search?q=infi...=1920&bih=1065

[mitch_04]

The console subwoofer enclosure has been done before, a buddy of mine has one in his CJ. From my personal experience, subwoofers tend to sound better when they "reflect" off of something. Hatchback Camaros with subs in the back facing the rear window are a great example of this. The sound reflects off the back window and spread throughout the cabin perfectly. If you decide to design a console enclosure, I would take the sub, keep it in the box it came in, and play music while facing the subwoofer different directions. Vertical, horizontal, rearward, forward, etc etc. You may find (my guess) that the subwoofer facing rearward sounds the best. Lower frequencies don't need to be pointed at you like higher frequencies do, this is why a subwoofer for a home stereo can be placed most anywhere in the room facing any direction. Component speakers, however, should be pointed in your general direction.

[scott_fx]

The console subwoofer enclosure has been done before, a buddy of mine has one in his CJ. From my personal experience, subwoofers tend to sound better when they "reflect" off of something. Hatchback Camaros with subs in the back facing the rear window are a great example of this. The sound reflects off the back window and spread throughout the cabin perfectly. If you decide to design a console enclosure, I would take the sub, keep it in the box it came in, and play music while facing the subwoofer different directions. Vertical, horizontal, rearward, forward, etc etc. You may find (my guess) that the subwoofer facing rearward sounds the best. Lower frequencies don't need to be pointed at you like higher frequencies do, this is why a subwoofer for a home stereo can be placed most anywhere in the room facing any direction. Component speakers, however, should be pointed in your general direction.

why it sounds better is more a matter of distance of the soundwave needing to travel to reach your ear, not about spreading through the cabin. Also subs (be it at home or car) are placed anywhere, but its not always optimal. there are things like corner loading to factor in and it also matters how high it's crossed over at. If you have tiny cube speakers that are crossed over at ~125hz... then sub placement is very crucial. It will be far easier to localize the sub if it plays that high.

[andrewb70]

Well...I got the sub today. For being only a 6.5" driver, it isn't terrible. The bass is tight, but pretty far from even shaking the rear view mirror. For anyone that wants a removable sub, this thing can easily live behind the driver's seat, deliver decent bass, and be easily removed for track days. I'll probably end up putting it in my little Mazda truck which has limited space behind the seat. Perfect for that.

While I was playing around with it, I started looking at the install of the 10" that I had under the rear package tray. I started pushing things around and it was pretty clear that the while contraption was held with bailing wire and gum. So much for a "professional" installation. So I decided to rip the whole thing out. The box was poorly made, had a whole drilled in the side for the wire, so it wasn't even sealed. It was just a mess.

On the bright side, I pulled the driver out and was delighted to see that it was a Diamond Audio M6104D. I always thought that I had a M3, but damn...I must have gone all out. This thing is older, but has dual 500W voice coils. It's a beast. I clearly didn't have enough power for this thing and I need a better box and a different mounting scheme...

The tinkering continues...

Andrew