Menu
Forum
What's new
New posts
Live Activity
Search forums
Members
Registered members
Classifieds Member Feedback
Car Audio Discussion
General Car Audio
Car Audio Build Logs
Car Audio Equipment
Subwoofers
Speakers
Amplifiers
Head Units
Car Audio Help
Wiring, Electrical and Installation
Enclosure Design & Construction
Car Audio Classifieds
Car Audio Classifieds
Car Audio Wanted
Classifieds Member Feedback
Gallery
New media
New comments
Search media
SHOP
Shop Head Units
Shop Amplifiers
Shop Speakers
Shop Subwoofers
Shop eBay Car Audio
Log in / Join
Test
Forum
Search
Search titles only
Search titles only
Log in / Join
Search
Search titles only
Search titles only
What's new
New posts
Live Activity
Search forums
Members
Registered members
Classifieds Member Feedback
Menu
Reply to thread
Forum
Car Audio Help
Enclosure Design & Construction
**Would I LOSE SOUND OUTPUT on a DOWNFIRED Box?**
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
<blockquote data-quote="JimAckley" data-source="post: 7483054" data-attributes="member: 633676"><p>Your losses, if anything, should be minimal. For the most part, bass is about pressurizing the cabin of your vehicle, and isn't <em>completely</em> directional. As long as you have a couple inches minimum between the drivers and the floor, you'll be fine. On the downside (pun very intended //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif), a down-firing setup will send acoustic energy outward in every direction, so you're not going to get the brute force of the energy you're creating. In some vehicles, that's good. I did a conversion van a couple years ago where we made a down-firing enclosure and that was the only thing that sounded good throughout the vehicle regardless of the seat. Also, the guy had kids and didn't want them accidentally damaging the sub, so it was a win-win all around.</p><p></p><p>I've had the most success with an all-rear-firing setup in a SUV. In that particular style of vehicle, it functions similar to one of those nasal-sounding bullhorns/PA horns, where a small diaphragm fires into a horn that reflects and amplifies the sound using a small amount of power, but it won't function as well until you put Dynamat or a similar material on your rear hatch/doors, roof, etc.</p><p></p><p>Your biggest source of parasitic loss is vibrating body panels, and the introduction of road noise while in motion. SUVs and vans suffer from this more than any other vehicle because of the large, long roof and larger body panels. Try to reinforce and/or dampen your roof, as well as dampening the rest of your vehicle. The less your car's body is moving, the less SPL you're missing out on, plus it has a much cleaner appearance when you're filling the air with sick bass and it doesn't sound like your SUV's about to rattle itself apart.</p><p></p><p>When it comes down to it, what you honestly need to do is go to the store and buy a sheet of MDF, and make a couple boxes. Start off with an enclosure that has your subs upfiring and ports rear firing. Then flip it over to see how it sounds with them downfiring (be sure to leave a few inches of clearance for your drivers to move/breathe). This is best when you have a friend around to help you out, so you can stay up front and listen while they flip your box. Then try an enclosure with everything facing the rear. If you wanna get really fancy, get an SPL meter (available at RadioShack) and run test tones through your amp from a laptop, and record the SPL levels from 20-80 in 5Hz increments. Then chart them out and see which box plays with the curve you desire.</p><p></p><p>What SUV are you putting this in?</p><p></p><p>edit: be sure that when you're testing enclosures, you have your doors shut and windows up/down or however you would keep them when you're driving. And for Pete's sake, test it in a big parking lot, not your driveway.. My next door neighbor walked all around my block trying to figure out where the bass was coming from that was rattling every single window in her house so badly because I was testing a pair of Treos on a 6kW amp in my driveway. Since then I've always done it somewhere public and away from homes.</p></blockquote><p></p>
[QUOTE="JimAckley, post: 7483054, member: 633676"] Your losses, if anything, should be minimal. For the most part, bass is about pressurizing the cabin of your vehicle, and isn't [I]completely[/I] directional. As long as you have a couple inches minimum between the drivers and the floor, you'll be fine. On the downside (pun very intended [IMG]//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif[/IMG]), a down-firing setup will send acoustic energy outward in every direction, so you're not going to get the brute force of the energy you're creating. In some vehicles, that's good. I did a conversion van a couple years ago where we made a down-firing enclosure and that was the only thing that sounded good throughout the vehicle regardless of the seat. Also, the guy had kids and didn't want them accidentally damaging the sub, so it was a win-win all around. I've had the most success with an all-rear-firing setup in a SUV. In that particular style of vehicle, it functions similar to one of those nasal-sounding bullhorns/PA horns, where a small diaphragm fires into a horn that reflects and amplifies the sound using a small amount of power, but it won't function as well until you put Dynamat or a similar material on your rear hatch/doors, roof, etc. Your biggest source of parasitic loss is vibrating body panels, and the introduction of road noise while in motion. SUVs and vans suffer from this more than any other vehicle because of the large, long roof and larger body panels. Try to reinforce and/or dampen your roof, as well as dampening the rest of your vehicle. The less your car's body is moving, the less SPL you're missing out on, plus it has a much cleaner appearance when you're filling the air with sick bass and it doesn't sound like your SUV's about to rattle itself apart. When it comes down to it, what you honestly need to do is go to the store and buy a sheet of MDF, and make a couple boxes. Start off with an enclosure that has your subs upfiring and ports rear firing. Then flip it over to see how it sounds with them downfiring (be sure to leave a few inches of clearance for your drivers to move/breathe). This is best when you have a friend around to help you out, so you can stay up front and listen while they flip your box. Then try an enclosure with everything facing the rear. If you wanna get really fancy, get an SPL meter (available at RadioShack) and run test tones through your amp from a laptop, and record the SPL levels from 20-80 in 5Hz increments. Then chart them out and see which box plays with the curve you desire. What SUV are you putting this in? edit: be sure that when you're testing enclosures, you have your doors shut and windows up/down or however you would keep them when you're driving. And for Pete's sake, test it in a big parking lot, not your driveway.. My next door neighbor walked all around my block trying to figure out where the bass was coming from that was rattling every single window in her house so badly because I was testing a pair of Treos on a 6kW amp in my driveway. Since then I've always done it somewhere public and away from homes. [/QUOTE]
Insert quotes…
Verification
Post reply
Forum
Car Audio Help
Enclosure Design & Construction
**Would I LOSE SOUND OUTPUT on a DOWNFIRED Box?**
Top
Menu
Home
Refresh