Sub placement

[Ceezer 10+ year member]

I currently have a box with a pair of 10s in the cargo area of my Subaru OBS wagon and have grown tired of not having room to put much of anything else back there so I've been tossing some alternatives around in my head.

My initial thought was to get a cargo basket for my Yakima rack and relocate the spare up there and fill the well with an enclosure, but:

a) with twin steelhead rails there's only enough room for a small basket and that's not large enough for a full spare (and I don't want to drive around with a donut on display...)

b) it seems like having the floor in place over the sub would distort the sound and possibly even rattle around. I suppose you could cut a hole out around/over the sub but I wouldn't want to leave it unprotected for when I toss gear back there

c) gah... I had a 'c' but it slipped my mind

So I'm thinking I might be ahead to try and build an enclosure for the corners, though I have absolutely no experience with fiberglass. I'm wondering what the better options would be for sound.

I listen to lots of loud rock and other genres, but my daily preference is y'allternative/cowpunk/hellbilly/streetgrass/etc. So I like clarity for the guitars/mandolins/banjos/etc but I need to have a little bottom end for when I'm pounding out some Soulfly or bumping some (hed). The two 10s have taken care of that for the most part (though... is it *ever* loud enough?), so I wouldn't want to go any smaller than that.

Would it be more beneficial to put a 10 in each corner, or just a single 12 in the bigger, passenger pocket/corner (and depending on how that turns out, I may use the other corner to create a mounting surface for the amp. otherwise I would probably just move it under one of the front seats)? And to maintain a balance of SQ & SPL, how should I position it/them? Angled towards the front of the car? Up and towards the hatch? Straight out?

Another thought I had (let's call it option 2a) was, if I went with the single 12, and it turned out well, maybe removing the center armrest/console and somehow incorporating an 8 into the back of it for the back seat. Hmm, I guess those sound waves would interfere with the ones coming forward from the 12. Disregard...

Regarding the act of laying fiberglass and such, for how long of a period is it a hazard to my health? As I said, I don't know what I'm doing so it could take a few days/tries to get it right but this is my daily driver and I have an hour commute. Is it only a concern while you're actually laying the mat & resin, or would I still be at risk the next day or two as it cured?

Click to read more...

 

[bones22 5,000+ posts]

wow thats a long read i cant do it

short version?

 

[Ceezer 10+ year member]

I guess this would be the 'meat' of the post:

I listen to lots of loud rock and other genres, but my daily preference is y'allternative/cowpunk/hellbilly/streetgrass/etc. So I like clarity for the guitars/mandolins/banjos/etc but I need to have a little bottom end for when I'm pounding out some Soulfly or bumping some (hed). The two 10s have taken care of that for the most part (though... is it *ever* loud enough?), so I wouldn't want to go any smaller than that.

Would it be more beneficial to put a 10 in each corner, or just a single 12 in the bigger, passenger pocket/corner (and depending on how that turns out, I may use the other corner to create a mounting surface for the amp. otherwise I would probably just move it under one of the front seats)? And to maintain a balance of SQ & SPL, how should I position it/them? Angled towards the front of the car? Up and towards the hatch? Straight out?

 

[IDSkoT 5,000+ posts]

Well, this is argued about daily on this forum.

Bass travels in a very linear path. You could put a sub in the back facing the corner of the car, and it will sound the same as if the woofer was placed in any other direction. However, when it comes to loudness and pressure, that's a difference. You'll only be able to tell it's coming from behind you. Since your car is a wagon, it has a shared cab/trunk, so in most implements, the loudest setup is subs up, and if you have a port, port back. Since you want to use the corners of your car, I'm assuming you're going to be losing space... regardless, this will make the driver work harder, so it won't be as loud in the confined spaces.

You haven't really given us any numbers or anything... so I'm not really sure what you're working with.

Now, as for the subs... SIZE OF THE CONE HAS LITTLE BEARING ON THE LOUDNESS. It's true a motor with a 12" Cone has the CAPABILITY of producing more pressure than a 10" cone with the same motor, but it's not always true. So, that schism of LOUDER CONE = LOUDER BAZZ is ludicrous.

BASICALLY, post up some numbers (of your amp), the maximum dimensions of your box, and if you're gunna buy new subs, price range... and we could help. (also the specs of your current sub)

EDIT:: I just read your original post never mix cone sizes. Ever.

And as for fiber glassing, I believe it's only hazardous when you first lay it. However, when doing a fiberglass project, most people put aluminum foil / masking tape behind what they're fiberglassing so it's easy to take out. You can take it out before your daily commute, if you want, by doing this.

 

[Ceezer 10+ year member]

What's the reasoning behind not mixing cone sizes? Even if they're in different locations? I've been "out of the game" for nearly 15 years, but in the early 90s it seemed common to see a 15" for bottom-bottom end and then a pair of 10s or 3 8s to fill in the tight hits.

The way I have it pictured in my head, the corner enclosures shouldn't take up too much space because these pockets are too small (and oddly shaped) to really hold anything, and if it works the way I'm envisioning then it will sit up off the floor so I'll still have that space. I'll go snap some pictures here to show y'all, if that will help. And the biggest obstruction with my current box is that it prevents me from laying the seats down and expanding my cargo space.

I asked about the fiberglass because I had heard somewhere that it shouldn't be moved/removed until it was fully cured. I don't know how true that is, just something I kept in mind.

My current setup is pretty much amateur. 4 years ago, when I replaced my head unit (Pioneer DEH-P7600MP), I also replaced the door speakers (TS-A1680R 6.5 4-ways in the front, 4.0s in the back) and needed something out back to hold me over so I went back to the local shop and picked up a basic package deal. It was a pair of Alphasonik Q-Reference QW10s in a ported box with a Q-Reference Q2150 amp. It's an appetizer... enough to stave off the cravings, but not really satisfy the hunger. I returned to the shop later to pick up an amp for the front speakers, but instead picked up a 4-channel amp (Distinct Audio By Crossfire, td.704; I'd never heard of the brand since I haven't followed CA stuff for more than a decade but they said it was a good amp) and just hooked the front speakers up on 2 channels and the subs on the other 2. I still have the Q-Ref amp so I don't know if adding it back in to the system to supplement the DA amp would make much difference, or not.

I can't find the DA amp on Google to get the numbers from it, and the paperwork is burried out in my garage. I was able to find that combo package I bought:

http://www.sonicelectronix.com/item_3010_Alphasonik+Combo+Q-Reference+Series.html

 

[IDSkoT 5,000+ posts]

The reason of not mixing cone sizes, IIRC, is about wave speed and acoustics. But, I could be wrong. I just know it's a no-no.

As for your gear, running a sub off 75 watts won't get very loud...

Generally front-stage 2-way comp sets are run off 75 watts, and most subs are run off 250+ watts.

Your subs are 200-RMS (I think it's RMS, I can't find a good site with info on them)

But, post up some pictures with some dimensions, you might be able to get away with it.

 

[Ceezer 10+ year member]

Pardon my ignorance, but how do you figure they're running off 60W? They're currently using 2 of the 4 channels on a 700W amp. I realize that doesn't mean they're pulling 350W, but I'm interested in hearing how you came to that number.

 

[IDSkoT 5,000+ posts]

Pardon my ignorance, but how do you figure they're running off 60W? They're currently using 2 of the 4 channels on a 700W amp. I realize that doesn't mean they're pulling 350W, but I'm interested in hearing how you came to that number.

I edited once I actually looked up the numbers on your amp.

The amp is 75x4 RMS power. That's at 4-ohm, and most comps are 4-ohm, but I didn't look up the coil set up on your subs. So I guess they might be running at 100 RMS or so?

 

[Ceezer 10+ year member]

I have them bridged (that's what we used to call it, anyway, where it would use the pos terminal from one channel and the neg from another) across two channels at the amp (and I think they're wired in parallel in the box). Would this make a difference on the power they're drawing?

I guess I really need to brush up...

 

[Ceezer 10+ year member]

I'm looking into replacing most of the components for higher quality pieces, but in the meanwhile is there another way I could hook this stuff up to get more power from it? Should I add the Alphasonik amp back in?

The front doors are running off 2 channels of the DA amp (in stereo? Right speaker to 1 channel, left to the other). Subs are running off 2 channels of the DA amp (in mono? Neg terminal from one channel and pos terminal from the other). Rear doors are running as fill off the head unit.

Should I incorporate the Q-Ref amp in there somewhere?

Also, I may have the subs hooked up to the rear pre-amp outputs on the HU instead of the sub pre-amp output. Would this make a difference, and how much?

 

[Ceezer 10+ year member]

Ok, I thought I'd bump this since it had pertinent information regarding the subs/amps.

This weekend I'm gonna try my hand at fabricating a fiberglass enclosure for the back corner of my cargo area and for my first attempt I'm going to make it just for a single 10 out of my existing box (I still plan on upgrading everything, but after the holidays; for now I want to play around). If I stick with just the single DA amp for now and keep the front coaxials on 2 channels then bridge the single 10 across the other 2 channels, would it then be pulling 150W RMS? A little more? A little less?

If so, how would a single sub being fed 150W sound, in loudness, compared to 2 subs getting 75W each?

 

[Ceezer 10+ year member]

Bump, I'm wanting to get this started Friday