Sub Placement/Direction (wagon)

[Sarthos]

I'll post this here so maybe I can get more feedback.

Anyway, I have a cb9 wagon now that my cb7 is kinda...yah. So, the wagon's gonna get the killer system I was building.

So, gonna put some subs in my trunk. A pair of 10s, with about 400 watts each. For the most part, I don't play music with a lot of bass. I like stuff like Johnny Cash, Eagles, Elvis, or Pink Floyd, not just a bunch of ghetto hip hop crap. So, two tens in a sealed box or boxes. My choices are either

1. Subs in very back corners of wagon, pointing forward
I think this method will sound cleaner. Less rattling of the tailgate, and a more direct sound without echos and distortion from the tailgate.

2. Subs in front of cargo area, pointing backward
This method results in making the car "seem" 2 or 3 feet longer. The result is that the strongest frequency to reach the my ears will be lower. The bad thing is that it means the sound bounces off the tailgate, gets delayed more, makes time alignment a little harder, rattles the tailgate more, and I think the sound might also propagate in ways that would cause the sub to echo and just not sound very good.

3. Run the pair of tens and other subs.
This would mean run the tens, sealed, in the very back, pointing forward, get the high bass good, and run some 12s or a 15 ported in the front, firing towards the tailgate. This would be more expensive and require more tuning work (EQ, time alignment, etc) and I'd put the other subs on a switch so I can use them ONLY when I want louder bass.

So, any opinions on any of these three methods? I'm liking either 1 or 3. Or at least starting with 1 and changing to 3 in the future if I want more power.

[sonikaccord]

Number 2
http://www.installer.com/tech/aiming.html

It has a horn-loading type effect and reinforces the bass.

[Sarthos]

Err...that website you posted doesn't seem to recommend number 2...it seems to recommend them in the far back of the trunk, not the front of the trunk. But it recommended pointing them backwards at the back.

And I really wish they labeled the graphs better. It took a little thinking to figure out which was which.

One problem I do have with the graphs though, are the waves that the sub pushes backwards really as strong as the ones it pushes forward? I always sorta thought the front of the sub was the strongest. which would mean sub forward would mean less trunk rattle. But assuming the front and back waves are equally strong it makes perfect sense to point it backwards. I'll just have to deal with more trunk rattle because the speaker is closer to the trunk. Damplifier Pro should help. Hopefully it doesn't weaken the reflected wave enough to make my system weaker though.

Really good read though. Nice to see some actual science being applied. I'll have them way in the back and pointing back.

[sonikaccord]

Err...that website you posted doesn't seem to recommend number 2...it seems to recommend them in the far back of the trunk, not the front of the trunk. But it recommended pointing them backwards at the back.

And I really wish they labeled the graphs better. It took a little thinking to figure out which was which.

One problem I do have with the graphs though, are the waves that the sub pushes backwards really as strong as the ones it pushes forward? I always sorta thought the front of the sub was the strongest. which would mean sub forward would mean less trunk rattle. But assuming the front and back waves are equally strong it makes perfect sense to point it backwards. I'll just have to deal with more trunk rattle because the speaker is closer to the trunk. Damplifier Pro should help. Hopefully it doesn't weaken the reflected wave enough to make my system weaker though.

Really good read though. Nice to see some actual science being applied. I'll have them way in the back and pointing back.

oops. Yeah I meant that way.

The sub is pressurizing the cabin. Imagine blowing into a paper bag. This is what the sub does when it moves out. When you suck the air out of the bag, this is the same as the sub moving in. You can imagine the panels of your car as the paper bag and you are the subwoofer. Now when you do both of them really fast, the thinner and more flexible panels are going to vibrate more than the thicker and stiffer panels. That's how you get "trunk rattle."

What dynamat or any other cld on the market does is make the thinner panels heavier and damps them so that they vibrate less and you get less rattle.

[sick6sect]

Point both of them to the rear, you will not be able to hear rattling inside vehicle if you have decent tweets and mids. You will however, hear it very well outside. Can be solved with Dyna-mat and rubber washers.

[Sarthos]

That does make sense with the paper bag analogy. But that must be more true for subwoofers and tweeters, otherwise I would assume people would mount their speakers with the magnets practically touching the doors to prevent cancellation (much shorter distance at high frequencies). But I suppose that dynamat helps kill a lot of the reflected wave on speakers.

So what, you expect the mids and tweets to cancel out the rattling? That's not exactly true...even 500 watts on mids and tweets won't cover up trunk rattle. Unless you have like 25 watts on the subs...and they happen to be 8" subs in a sealed box.

I know Dynamat and other stuff helps because the heavier panels vibrate less. I assume that it also weakens the reflected wave somewhat, not 100% sure on that though.

[sonikaccord]

It's more true for subs because they move so much air compared to smaller speakers and higher frequencies. As for reflected waves, the only way those can be canceled or diffused is if you get rid of all of the hard surfaces in the car which is almost impossible.

Stopping rattle doesn't just stop panels from making noise. When a panel vibrates it creates it's own frequency and can interfere with the sub's sound. That's why some boxes are braced, to stop the panels from flexing.

[Sarthos]

Ha. That's how I built my first box. Super ugly with 2 12s, but it was 3/4" oak with 2x4s bracing it down the center and one behind each sub. Coated in fiberglass resin too.

Actually making noise automatically interferes with the sub's sound. Hence my want to eliminate rattle.

[masterbarber]

Subs facing back, go with a good set of 6.5 mids & tweeters. If you can get the flush mount even better. With 2 10" & 400wts each sub you not gonna have a big ass rattle. Just get a good set of mids & highs and a 4 channel amp at least 250.4 and you be good. On my wagon i have try eeeeeeeeverything...lol

[mr_naler]

Well this has mad me reconsider what I'm going to do as far as building a box, and placement of said box. I guess if I want better sound quality I'll go with rear firing sub at the very rear of my trunk.

I am going to be gutting my trunk though. Does anyone think this will effect anything?

Also, in what direction should my port be firing? Front/Rear/Side

[Sarthos]

Of course I'll make sure to have good mids. I listen to country, my first system didn't even have subs it was 4 alpine 6.5 Type R Coax with a 95x4 Rockford amp. Lately I've been running 150x2 to a pair of MB Quart QSD 216 component speakers in the front in door pods and I really like that. I'll add rear fill when I get into the wagon some more.

Flush mount...you mean flush mount tweeters in the pillars or something?

250.4, does that mean 250 watts RMS x 4 channels? I don't know of many speakers that can handle that. Or does that mean 250x4 peak?

I was concerned with rattles mainly because my cb7 sedan rattled like crazy with 2 12s sealed even with dynamat all over.. But they did have more wattage, and I think a lot of the rattle was from the spoiler which I wanted to get rid of so badly. Might not have that problem with the wagon.

mr naler, gut your trunk and soundproof it. The one problem with gutting it is that the interior of the trunk acts as a little bit of insulation. If you use dynamat or damplifier or whatever it should add a bit more ability to block out noise and insulate heat than when you had the interior in.

[charles.scarlet]

in the back facing the back.

[onelivinlarge]

sub up. port back. end of story because wagons r like suvs and have similar acoustic traits. this is the best set up for a wagon. if u want loud in a sedan/ coupe subs back port back. if u want spl subs forward port forward... if u want how to do subs forward in a cb7 and be loud that i can show u

[Sarthos]

what port?...

[sick6sect]

He is talking about a ported box, I like sealed myself. More punch than rumble.