General Stereo question

[Rexmobbin]

so i bought a DVC 4 ohm sub (4ohms per VC). are my only options for wiring this thing 8ohm and 2 ohm? i can't just use one VC and do a 4 ohm load can i?

[Th3Franz]

You can use just one voice coil but it won't perform very well at all. Your best bet is to run it at 2 ohm (parallel).

[PGT]

You must use both voice coils. What brand of sub is it? What kind of amplifier?

[c_hunter]

If possible, just drive it with L going to one coil and R going to the other. That's the easiest route and it's really what the sub is made for. Craig

[PGT]

[quote name='c_hunter']If possible, just drive it with L going to one coil and R going to the other. That's the easiest route and it's really what the sub is made for. Craig[/QUOTE] Actually, that's not entirely true. DVC subs are for flexibility, not just stereo. It depends what brand they are and the quality of the amp. For example, JL Audio W6 woofers have dual 6 ohm coils, so you would want to bridge the amp to mono and run the coils in parallel for a 3ohm mono load. Some amplifiers are designed to run low impedance loads, like mono D class amplifiers. The conclusion is that no one can determine the optimum set up until we know what amplifier is driving the load.

[Rexmobbin]

well, no worries. i bought a Diamond Audio 12" (forgot the model name) for a pretty decent price. the amp wasn't stable into 2 ohms, so it was either run it at 8ohms (which would cut my amp's power in half) or 2 ohms, and risk burning the amp out. i ended up using my 15" from my Acura, and got a nice 4 ohm load (RMS output on the amp is 800 watts into 4 ohms) and some bangin' bass. c_hunter, isn't your setup gonna double the impedance? patagonian, the amp is a Soundstream Van Gogh, the Sub i'm using now is a RF Power HX2 15

[Th3Franz]

Ack, a nice amp and an HX2? I'm sorry. :( (Unless SPL is more your thing but from the sound of it, it's not.) Try running it at 2 ohms but just keep the gain low and see how it does. That amp should have protection so if it cuts out, then you'll have to go from there.

[c_hunter]

[QUOTE=Rexmobbin'] c_hunter, isn't your setup gonna double the impedance? [/QUOTE] If each coil is powered by a single channel, then each channel will see a 4 ohm load, which is sort of the standard load for car audio. That's the idea of a DVC sub. I know you can hook up a DVC sub all kinds of different ways, but they are really set up so that you can run L and R leads to one single driver (since the stereo effect doesn't matter with low frequencies, it's easier to have one sub -- more compact). If your amp or stereo has a single channel output for the sub, you are better off using a single VC sub for that application. A single VC sub will always be more efficient than a DVC sub when operating on one channel. Craig

[PGT]

[quote name='c_hunter']If each coil is powered by a single channel, then each channel will see a 4 ohm load, which is sort of the standard load for car audio. That's the idea of a DVC sub. I know you can hook up a DVC sub all kinds of different ways, but they are really set up so that you can run L and R leads to one single driver (since the stereo effect doesn't matter with low frequencies, it's easier to have one sub -- more compact). If your amp or stereo has a single channel output for the sub, you are better off using a single VC sub for that application. A single VC sub will always be more efficient than a DVC sub when operating on one channel. Craig[/QUOTE] I spent four years designing and selling car audio systems at a hi-end shop (mostly $3-20K systems) and never once set up a system the way you described, even if it was a $500 budget system. Amplifiers are most efficient at driving low frequency loads in four ohm mono mode - this gives you double the effective power (75 x4 = 300watts) than driving a four ohm stereo load (75L +75R = 150 watts total). The standard mode for driving full frequency, stereo speakers is 4 ohm stereo. If you only have a single 4 ohm dvc to work with, there aren't many choices unless your amp can drive a 2 ohm mono load (same as 1 ohm stereo). 4 ohm DVC's are always sold in pairs, so there would never be a reason to use a single DVC sub unless you picked it up second-hand. There is actually some science behind DVC's - with twice the copper windings on the voice former or throat, DVC's have better thermal characteristics (read power handling) than SVC designs. Look at any hi-power home subwoofer and you will almost exclusively see DVCs. Some even go to the point of having two DVCs and two motor structures (spider and basket) attached to one piston driver (woofer). This gives extreme control and the capability for long throw (volume). A woofer acts just like a piston....more air moved equals louder volume. The frequency is controlled by piston speed - so loud, low frequency performance needs extreme control: [url]http://www.hamysound.com/marques/HPHGS.jpeg[/url] I know.....more than anybody needs to know about audio.

[Rexmobbin]

well, i got rid of the HX2, TOO big and heavy, didn't need an extra 60 pounds in the trunk. ended up with the DVC 4ohm 12" in a ported box, wired so the amp is seeing 8 ohms. even though it's cutting my RMS amp's output in half, the bass is plenty. sounds pretty decent too, everything from Mac Dre's "In Motion" (DEEP DEEP bassline) to rock (more midbass) is well represented. now i just gotta get a way to keep the box from sliding around. anyone know how thick the trunk floor is before i'm screwing into the gas tank?

[D-2.5-GT]

A good rule of thumb, is drill first, ask questions later....

[PGT]

I have one possible solution that is secure but allows you to remove it later with no apparent changes. Try going by a local stereo shop and getting some mounting brackets for a CD changer. Most of them have metal plates with two small bolts.......place these under the carpet to the side of where the sub enclosure should be (use a razor to cut an 'X' for the bolt to come through the carpet). The other half of the CD changer brackets are usually molded plastic (or metal) - Screw these to your sub enclosure. Basically, you can place the box (with brackets) in position and insert the bolts into them use wingnuts to secure. The box won't move at all and is easy to remove. Best of all, you can go back to stock and no one will notice. I will raid my parts bin in the garage and see if I have the pieces to take pics of, if that helps.

[Rexmobbin]

[quote name='patagonianwrx']I have one possible solution that is secure but allows you to remove it later with no apparent changes. Try going by a local stereo shop and getting some mounting brackets for a CD changer. Most of them have metal plates with two small bolts.......place these under the carpet to the side of where the sub enclosure should be (use a razor to cut an 'X' for the bolt to come through the carpet). The other half of the CD changer brackets are usually molded plastic (or metal) - Screw these to your sub enclosure. Basically, you can place the box (with brackets) in position and insert the bolts into them use wingnuts to secure. The box won't move at all and is easy to remove. Best of all, you can go back to stock and no one will notice. I will raid my parts bin in the garage and see if I have the pieces to take pics of, if that helps.[/QUOTE] so, you're saying that just putting the brackets under the carpet, and not screwing them down is the way to go? would that be strong enough to not rip out from under the carpet during a hard turn you think?

[PGT]

What shape and size is the enclosure? Is it carpeted? From what I remember, ported 12 enclosure was rather large, meaning it was a tight fit in many cars. If your box is built to spec for a ported enclosure, you just need to keep it from sliding. The brackets should work fine, as the weight of the box on the carpet will also keep things from moving much. I had a small sealed enclosure (1.5 cu ft) in my CRX for two 10W3s, and used only that non-slip mat material (like the kind to line the drawers in a tool box or goes under carpet on a hardwood floor) between the carpet and the cover for the spare. I had a rear strut bar very close over the sub enclosure, so I used a small block of wood (carpeted to match) to 'pin' the bar up and hold the subs in place. I never had any issues and that car could turn harder than anything we would do in an LGT. Maybe take a pic of what you are looking at and I could come up with something creative.....that's what I used to get paid to do.

[PGT]

[quote name='D-2.5-GT']A good rule of thumb, is drill first, ask questions later....[/QUOTE] Yeah, it's quicker for sure. But as one of my installers learned before I fired him, it's not always a good idea. :lol: He drilled holes into the third firewall of a '99 NSX to run power cable from a front mounted battery to an expensive amplifier and also drove drywall screws into the gas tank. Let's just say nobody noticed right away....but after the fan-cooled ADCOM amp began to rust, the owner took the car to the dealer to check for leaks. We ended up swapping out $5K in equipment and had to pay for a new gas tank and the dealer's labor bills. The installer had a choice of paying half of the cost (the deductible for insurance), or walking.

[Rexmobbin]

well, the box is kinda odd shaped. it's an Audiobahn box, and i know it's not built to spec for this particular sub, but the size is nice and it sounds very good. here's the box. i have it mounted so that it's facing side to side. i have griptape on the bottom of it to keep it from sliding, but the other day, i took a HARD left, ane the thing flipped over on me. it's set up right against the back seat...

[PGT]

gotcha. Your best bet may be to use some basic tie down straps.......since the shape is round. You can buy a pair at most places like Wal-Mart.....although I would probably use something like this (I have some extras for my kayaks): [url]http://www.nrsweb.com/shop/product.asp?pfid=1440&deptid=1188[/url] You would only need two, about 3 or 4 feet each (however long to wrap around the enclosure and meet the cam). Put a screw through the middle of the strap into something solid like the seat supports, wherever you want to mount the sub. It might be helpful to pull the carpet down off the seat to make sure you know where the supports are - and use short 3/4" 'stinger' screws (pan head and self tapping) - you don't want rear seat passengers feeling a 3" screw in their backs. Place the sub on the strap, and wrap the strap around and through the cam. That thing won't move, depending on where you secure the screws. By the way, Bazooka uses something similar to secure their enclosures. Basic 3/4" web straps and plastic buckles you could buy at any fabric store. Let me know if this works out....hard to tell without a pic of what you are tryin to do in the trunk.

[Rexmobbin]

i'll take a pic soon. it would be a little hard to get the straps up against the back on the metal supports, since that's where my amp is screwed into. i'm gonna look into it further, either with Patagonian's suggestion, or with some kind of large L bracket that i might not have to screw into the floor.