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New car sub, does this work? Answered

My cousin was nice enough to give me this nice little 200 watt 12 inch sub. It just needs some minor repair, theres a little puncture hole in the dust cap, simple fix. I tried hooking it up directly to my stereo and using the eq to filter out all the freq and still wasn't too happy. I took the amp out of my mirage sub and wired it all up to this one, the amp is only 75 watt rated, well I could be wrong, all I know was that the sub was 75 watt. But it works great, tell me if this is a good idea guys, lookin for opinions. Also too, is it normal that the heat sinks on the amp should be "energized"??? I picked it up by the heat sinks while it was plugged in before I had the sub and dropped it rather quickly, althought it seems to have loosened the joints up in my hand. Also too, does anyone know what brand of sub it is? All it says on the front and magnet is VR with a 12 in between (12 inch). I wanna find some specs for it as I'm not sure if the box it's in is tuned for it and I'm thinking about porting it or would that make it overdrive if it was ment to be in a sealed box?

Discussions

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germanboy

11 years ago

If you meant the heatsinks have a voltage on them by "energised", then no they shouldn't, you may have a grounding issue somewhere. Remember when matching speakers and amps that you must pay attention to their impeadance, and also remember that the wattage of a speeaker can be rated either in PMPO or RMS. Should help ya not blow your sub :)

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NachoMahmagermanboy

Reply 11 years ago

. As LV said, it's not uncommon for heat sinks to be "hot." You don't notice it with 5V and 12V systems, but it can be quite a surprise at higher voltages. . But that doesn't mean there is not a grounding problem, just that a "hot" heat sink is not necessarily an indicator of such.

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germanboyNachoMahma

Reply 11 years ago

Ah I see, I call "hot" live, just to aviod the confusion between heat and potential difference, which is the trap I fell into there, lol. I wasnt aware of heat sinks running live though, but I am more than likely wrong :D

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NachoMahmagermanboy

Reply 11 years ago

. Yeah. It is kinda confusing. I was hoping the quotes would help. . . I'd been putting mica insulators between voltage regulators/etc and chassis (chassi?)/heatsinks for years before I REALLY learned why the mica was necessary. Someone hadn't replaced the insulator when changing the component on a previous job so the heatsink was hot/live. :) Luckily, I wasn't grounded very well at the time.

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Punkguytagermanboy

Reply 11 years ago

They're both in rms according to the back of the sub and the specifications for the actual amp/origional sub on the site. And they're both 8 omhs, it won't drive any less.

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LasVegas

11 years ago

Yes. It's very possible that heatsinks can be "hot." Actually it's quite common. There's no way to tell what brand of subwoofer that is. The picture is just too blurry.

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PunkguytaLasVegas

Reply 11 years ago

It wasn't hot, I had just plugged it in, I meant that I had a few hundred volts run through my hand.

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LasVegasPunkguyta

Reply 11 years ago

That's what the term hot means. You're dealing with an isolated circuit with very high voltages. Many components may well have high voltage on the heatsinks. Unless the heatsink is grounded (attached to the chassis), you should treat them as dangerous and don't touch them when the unit is powered.

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PunkguytaLasVegas

Reply 11 years ago

Alright, thanks, I was getting a little worried thinking that I might blow another sub with this damn amp. I'm gonna cut a hole in the back, well make the one that's there a little bigger, and drop the amp in there. Also, I was wondering if it would hurt to port the box? What if I used the port off the old sub?

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LasVegasPunkguyta

Reply 11 years ago

I don't really understand what you're asking... That sub appears to be taking its sub signals off of the left and right speaker channels. If your amp has a sub output port, you would have to put it through a preamp first before feeding it into either channel since a sub channel is line level.

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PunkguytaLasVegas

Reply 11 years ago

Well what I meant by ported was "air holes" to let the bass out. And my reciever does have a line level sub out, but I can't turn it on without the remote, as it's turned off by default, so I have to use the high level inputs into the amp I pulled out of the blown subwoofer, that then goes into the actual subwoofer push leads (it's good quality, has gold push connects right on the basket). -Punk

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LasVegasPunkguyta

Reply 11 years ago

'd suggest leaving the "air holes" as is. They're acoustically tuned for the speaker. The function of a subwoofer isn't to make the low frequencies louder, but to spread them out throughout the room. For best effect, I just set the sub toward a wall. You shouldn't be able to tell where the very low frequencies are coming from.

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PunkguytaLasVegas

Reply 11 years ago

Uhh..there aren't any air holes, it's sealed, I was talking about "putting" one in, I just took a round cut bit for my drill (one with the drill bit in the middle and the hole cutting part is around the drill bit) and It's prolly something around a 4-5inch diameter hole. I used an online calc to find it and it was something around 5 inches.

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LasVegasPunkguyta

Reply 11 years ago

If there were no holes then the designer didn't see a need for baffle. Like I said, the purpose of a subwoofer isn't so much for sound but to distribute the subsonic vibrations throughout the room.

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PunkguytaLasVegas

Reply 11 years ago

Sigh, this is a crap box this guy glued together, and dropped the sub in, this ain't no "designer" box.

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Kiteman

11 years ago

What, speakers?

Rats, when I read the thread title I was hoping for a fun form of amphibious transport. Now that would be an instructable ...

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PunkguytaKiteman

Reply 11 years ago

Ah, but it will be once I move it into a car. Say, got a spare car amp you're not using?