This will require some thinking, but I'm going to make it work.

What are the specs on that box? i may have missed it in the thread. I still have that Sundown SD-2 from you, and built a box but cant seem to get any decent sound from it. I was wondering if I made mine too small/too big, maybe not air tight enough.....

 

Has to be 100% seal,
If your box is to small, you won't get any good lower freq extension and will drop off fast below a certain frequency but may make the higher freq more punchy and louder

 

Alright. So, it's spring time, when a young man's fancy turns to thoughts of stereo equipment. As most of you know, or have read in this thread, I have shoved two 12" subs behind the rear seat of my truck. I have been considering going ported, but that would mean losing one of the subs, and only having one 12" back there, and constructing an entirely new box.

What are the thoughts? I'd have 1200w feeding the one Shok Trition 12", and with a ported enclosure, I could theoretically really get lower on the bass notes, and, as one of my favorite bands say, "Shake the Foundations".

 

Well bud, I'll be making a box for the 2 8a ported which will end up a little bigger than needed but I'd rather it bigger than smaller. I can Lways do 2 boxes or you can come over N we can do both. We can easily do 2.25-2.5 cf net

 

Actually, it's an easy proposition for me to switch to ported. New baffle, and take the driver's side angle piece out, and cut it for the port. My big question, I guess I should have been clearer, would I see a gain from going to a single 12" ported, over 2 12" sealed?

 

Rather tough to say,
You may gain some and loose some depending on freq.
I have found our trucks to have a natural resonance of around 55hz so tuning low should technically provide you w that output down under and should continue flat across the freq spectrum. Truth be told, I haven't messed w this specific build to have an exact answer. If just experiment and see what you like more.

I tuned 28hz with all my setups and have a relatively flat rta

 

No. Theoretically, it should be the same general 'volume'. But your response will change. If you're happy with the way it sounds now, leave it.

 

Okay, thanks for the opinions and info guys. Time to give it a serious listen, not just bumpin' tunes, and seeing if I'm happy with it. I'll try it with a lot of different music, and see what I think. I'll let you know when I decide.

 

Okay, so with some serious listening, I've figured that the biggest output of the subs is in the 40-50Hz range. Say I wanted some deeper bass? Like some really loud, chest shaking bass in the 20-30Hz range? Would going to a single 12" ported be the way to go, or would I lose the output in the higher ranges like 50Hz and up? Don't get me wrong, it shakes the truck so much that I'm constantly adjusting my mirror, but if I wanted to dig deeper, and get louder in the lower ranges, like 20-30Hz, is ported my best option?

 

I don't think you're going to get really loud, chest shaking bass in the 20-30hz range no matter what you do. Unless you walled your truck and tripled the amount of drivers that you're currently using, of course. 20-30hz is very low, and you'd be hard pressed to even find a lot of music that has heavy bass lines at those frequencies.

That being said, in two applications using correctly built boxes with the same type of woofers, the ported enclosure will have a sharper drop-off at a lower frequency than a sealed box. See the graph below.


Notice the red line dropping off at about 10db/octave from 50hz. That is the ported enclosure.

Notice the purple line dropping off at a much steadier rate from about 80hz. That is the sealed enclosure.

The sealed box is actually LOUDER at 20-30hz than the ported box! The example shown in the graph is generally what you can expect from applications, but every woofer is different and in terms of response and sound quality, some woofers are better in a ported box.

I've never heard your set up, so I can only speak from experience with similar setups that I have heard. I would leave it how it is now.

 

what you say is true, but he'd most likely be tuning low 30s
your example is based on a 50hz tuning which no one really does unless ur pure Spl and listening to skooter.

With that said, the drop off below 33hz per say is almost negligible and with The 05+ tacoma resonant freq being around 48-55hz it blends rather well. Tuning 33hz will take him up to that region and generally wouldn't require to much eq work to have a nice flat response curve from 33hz up to mid range

Either way,
No one can really say what will be louder unless actually tested and verified via Termlab meter or equivalent to determine the EXACT difference across the freq spectrum with all things being equal

 

Hmmmmm. Thanks Shane, for the graph. It shows me a side of the sealed vs. ported argument that I haven't considered. I do agree, that most of my music is rock, and the bass guitar is generally played in the range that I find pleasing. But there is some synth music that I listen to, that reaches really low.

I'm going to have to put more thought into this. What concerns me is taking the side angle piece out and cutting a hole in it. It took me hours to form it around the back brace, halfway up the back wall, so that I could get a tight seal. I'd hate to pull it out, cut a hole in it, only to find out that I preferred sealed. I don't want to put that much work into another one. And creating another one is just as labor intensive, and because the box spans the back of the truck, I don't have an area that I can test the new piece on. Ah, decisions.

 

Richard, you can also look at http://www.bcae1.com/spboxad1.htm to get a better understanding of how tuning effects output, drop off etc..

But at the end of the day, its going to come down to :
Single 12 with 1200 wrms ported
vs 2 12 sealed on 1200wrms.

So ported vs double cone area....
If you want to swing by one of these days, ill let you know when we are building the next truck, come and listen and compare...

The next one will be competition sq system and should have almost flat response curve all through out the listening freq spectrum

 

That would be great. I'd get a better understanding comparing the two. Text me and I'll be there.

 

You also have to consider the cabin's environment. There could a bump in the mid 50s range, but is there also a null (dip) in the region you're wanting to get more output from? If there is a dip then going ported may not necessarily give you what you want. These physical properties of the automobile environment are hard to overcome. You will need an RTA and run frequency sweeps to see what kind of environment the Tacoma is giving you.

 

Very valid point.

 

So that's probably what I'm experiencing, and perceiving it as a boost in the 40-50Hz range, cabin gain. I'm probably getting the low end that I want, I just need to EQ a little, to see if I can bring it forward.

Manethon, please text me when you do your next build. I'm interested to see if I can get some of the 30-40Hz gain with a ported enclosure, and your next build may sway my decision.

 

Well, I got my mid bass to where I want it. Did a little investigation with the Alpine Tune It app, and my front mids were crossed over at 125Hz, with a 24db frequency cut off. Dropped it to 80Hz, with a 6dB drop, and the mid bass came to life! Sometimes I'm in too much of a hurry.

 

wow 125hz lol! no wonder bud! glad to hear its come to life
Those mids should be able to tolerate a 60hz cross over, see how it sounds at least

You may find that a single triton 12 ported tuned 30-33hz will do what you want it to do. The cabin gain is about 3-4 db around 49-55hz so with the ported box tuned 30hz ish as a theoretical should give you the bottom end gain you want and a relatively flat response across the whole freq spectrum. Then it will depend how well your mids will play down to the 60/80hz cut off

 

Okay, next question. Right now, the subs are wired for 4 ohm, getting 1200w between the 2. I have them wired with 16ga. wire. I read on another car audio forum, that I'm increasing the dampening factor, by choking the power that they see with the smaller ga. wire. What ga. would I need to get proper performance out of these. I think I'm keeping them sealed, just too much work to get it ported, unless I go with a slot port off the front of the box. So, do I need to step it up to 12ga., or would I go bigger?