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Upfiring vs. downfiring in extra cab '00

scottlambson

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scottlambson Enthusiast

scottlambson

Posted
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I currently have a downfiring prefabbed box under the rear seat of my 00 silverado with two 10" hifonics subs for the past three years. Sounds good with the cadence mids and two old school Zed audio built amps.

 

Anyways, I am planning on updating the subs with two Cadence 10" Beasts which require more than the .65 cu ft that is currently in the box. The plan is to fiberglass the bottom and contruct the sides and top from MDF to get the airspace. However I'm concerned that the upfiring subs will not sound as good as a downfiring enclosure. I can do downfiring but at a sacrifice of around .2 cu ft per side.

 

Anyone done an upfiring vs downfiring survey?

mmmikkke Senior Enthusiast

mmmikkke

Posted
Posted
I currently have a downfiring prefabbed box under the rear seat of my 00 silverado with two 10" hifonics subs for the past three years.  Sounds good with the cadence mids and two old school Zed audio built amps.

 

Anyways, I am planning on updating the subs with two Cadence 10" Beasts which require more than the .65 cu ft that is currently in the box.  The plan is to fiberglass the bottom and contruct the sides and top from MDF to get the airspace.  However I'm concerned that the upfiring subs will not sound as good as a downfiring enclosure.  I can do downfiring but at a sacrifice of around .2 cu ft per side.

 

Anyone done an upfiring vs downfiring survey?

 

 

 

It will be difficult to get unbiased opinions, and here's mine, and everybody's got one.

 

Upfiring and downfiring doesn't make any difference, as long the sound can exit from the front of the woofer(s) without significant reflection back into the face of the woofer. Bass below 100hz is not directional.

 

I built my own pair of downfiring woofer boxes, and because I didn't know what I was doing, I copied a design featured at subbox.net (click on it).

 

I ended up with each box having 0.6 cubic feet of air space inside. I mounted a pair of Infinity Perfect Kappa 10's, and installed them. Then I tested them with a test-cd and a radio shack SPL meter. They have a resonance around 70 hz, which I equalized out so that response if flat, but I think some of the reason for this resonance is the way that the sound has to travel to exit from the enclosure.

 

My downfiring boxes only allow the sound to exit at the ends. The front and back of the boxes extend out of the box-proper and project 2" downward, where they meet the carpeting of the floor. The boxes sit on these 2" extensions. So there's a tunnel under each of my downfiring woofer boxes, and I think this tunnel is not good.

 

To fix this, I plan on making another enclosure, this time a single enclosure, which will have more space inside, more like .75 cubic feet for each of 2 woofers.

 

I defer to the experts in audio, JL. They make an enclosure set (made of plastic, or fiberglass, or some similar material) that lets you run 2 12" downfiring subs. They put the subs at the extreme ends of the seat, and they let the sound out immediately to the side, and to the front, but not toward the driveshaft hump. There's no "tunnel." They use the floor space between the woofer and the driveshaft tunnel for enclosure volume. And that's what I plan to imitate.

 

JL also provides a mounting hole that securely mounts the enclosures to the floor, right next to the woofer, and this also I think is important to avoid resonances and other ear-fatiguing distortion.

 

To sum it all up, keep the tunnel to a minimum, and securely mount your box(es) to the floor. That's what's important.

masterp2 Enthusiast

masterp2

Posted
Posted
They have a resonance around 70 hz, which I equalized out so that response if flat, but I think some of the reason for this resonance is the way that the sound has to travel to exit from the enclosure. 

 

 

 

 

 

I find your results interesting. I had a similar hump at 50-55 HZ (sealed facing into seat backs). My feeling is that it is a vehicle (system) resonance. Mine being lower might be explained by the sound treatment I did, damping the panels does lower the resonance freq's of them, and collectively a lower system resonance would be expected.

 

FWIW, audiophile wisdom for SQ has all drivers firing into free space. Firing into a surface always has the effect of enhancing low end which may be desireable. The firmer the surface the more dramatic the effect.

 

I remember one time, in my 300zx with rear facing subs, I had put a bunch of large tubes in the hatch area, adjacent to the drivers, for transport. You wouldn't believe what that did for the low end thunder, not necessarily SQ.

 

Just sharing, don't mean to deflect the thread.

Guest 007FL

Guest 007FL

Posted
Posted

I have a downfiring sub in a custom enclosure. It sounds great.

 

FWIW, as long as you have a box already, you may want to put the new subs in it. Dampen the box with some fiberglass insulation and try them out. It costs almost nothing and you may well find that you don't need a larger box. You can always build a larger box if you'r not happy. The test will cost you about $5 and an hour of your time.

 

JMHO

profoundwill New Member

profoundwill

Posted
Posted

I have one ten in a custom made box, built by me, and my sub is firing down and it sounds great!! However my box is ported not sealed. The only bad thing about having it firing up is that it may be hitting the bottom of the seat, I had this problem in the past also, that is way I decided to build one firing down, which turned out to work a lot better. Think about like this, if the sub is facing down it is going to act like you are throwing a rock into water it is going to have the ripple effect and the bass will go out in all diretions evenly. With them facing up, if the seat is down most of your sound is going to get blocked by the seats and if they are up the bass is going to be going out all directions but not evenly, it will be a lot louder in the direction the sub is facing. I hope this helps, I am pretty good with car audio so if you have any questions hit me up!!

scottlambson Enthusiast

scottlambson

Posted
  • Author
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is that .65 for BOTH drivers?

 

 

 

 

Noooooo.... each. Stuffed pretty heavily with fiberfill too. The Hifonics are OW104s that are currently in the enclosure. WinISD suggests a .48cu ft enclosure for each sub with a Q of the box around .7 and the driver takes up .09 cu ft. So the sub matches the enclosure fairly well.

 

The Cadence Beasts require considerably more in all departments. Firing into the bottom of the seat may give some interesting effects. The few things I've read so far indicate the downfiring in the trucks minimizes cancellation.

 

My current enclosure is one big box under the seat with a divider in the middle. It uses the airspace above the hump but sits back from the edge about four inches on all sides. The sub fires backwards only. Sealed against the floor across the front and sides.

masterp2 Enthusiast

masterp2

Posted
Posted

sounds like you know exactly what you are doing. If you live near me I'd like to hear it.

 

Tell me about the rest of your sound if you will.

scottlambson Enthusiast

scottlambson

Posted
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Sorry Az a bit off. SE Idaho if you ever get up this way. Cadence components in the front CW6's and tweeters with the crossovers mounted in the doors in a pocket I build. Just a bit of custom mounting in the door to get them right. Tweeters are angled back.

 

I've used the rears and gone through quite a fews for better fill. Cadence 4X 6 plate that used a 3.5" mid and pivotable tweeter. Then a CW5Kit and now some Neos are going in the shallow space. Head unit is old now but still sounds great as a DXZ8575 coupled to a DPH7500z processor. It has a 6 disc changer in the drivers door pocket but with the new box I'm planning on using a 12 I've got laying around. Amps are old school US Acoustics US series 4050 and 2100. Cadence Z600 and Z1200 will be replacing them behind the rear seat.

 

sounds like you know exactly what you are doing.  If you live near me I'd like to hear it.

 

Tell me about the rest of your sound if you will.

 

 

 

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