Strange Subwofer Issue

[mhsnolie08 10+ year member]

I just purchased a new Alpine SWR 1243D and a new custom built alpine vented enclosure, at the bottom is the specifications for the enclosure. I had previously owned an Alpine SWR 1243D subwoofer that was in its own vented enclosure and it worked fine with the same amplifier. I took my old alpine and put it with the new one that I have purchased. The issue is that only the new one that I have is making a strange rattling sound when the amp is turned up. I have a Boss Audio Nx1800.1 1800W Mono Block Amplifier. I have been doing some research about this issue with the noise the subwoofer is making and I'm not real sure of the noise that I am experiencing. Two common terms I have seen are bottoming out and clipping. I just don't see how either of these could be the issue as it's only applying to one subwoofer and not both. I have an 08 Honda Civic with the factory head unit, I just used a LOC to connect the amp. I'm hoping it's a simple setup and not a messed up speaker because I don't want to have to return the sub. Below I have attached some additional pictures to show wiring setup and the setup of my system.

Dimensions:35"W x 14.75"H x 15.25"D

Cut out diameter:11 1/16"

Mounting depth:13"

Cubic Air Space:1.65 Per chamber or woofer

Tuned at 40HZ

Holds two 12" woofers

Constructed in premium 3/4" MDF

Click to read more...

 

[mhsnolie08 10+ year member]

I have the subwoofers each wired to 2 ohms. I tried to post picture of my wiring and my setup but cannot get them to post.

 

[jirehn 10+ year member]

What are the difference now after you attached this?

 

[mhsnolie08 10+ year member]

I'm confused as to what you're asking.

 

[Gregulate 10+ year member]

Those subs are rated for 300-600 watts and that amp puts out ~288 watts max, so you are severely under-powering them. That said, it should affect both subs equally and it just wouldn't be super loud. I assume you have them wired for a 4 ohm load?

Check this diagram and make sure it's wired correctly. You may have a loose wire or something.

 

[mhsnolie08 10+ year member]

I have them wired based on the crutchfield diagram. http://a248.e.akamai.net/pix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/1DVC_4-ohm_mono.jpg. They are wired parallel down to 2 ohms. This amp had no problem pushing a single 1243d to the point of distortion so I figured it would do okay to push both of the subs.

 

[Gregulate 10+ year member]

Hmm, I'm confused. Is this the sub? http://www.crutchfield.com/p_500SWR1243/Alpine-SWR-1243D.html?tp=111 You have two of them, right? Or is it just one that you replaced with the exact same thing?

 

[mhsnolie08 10+ year member]

That's correct, I have two of them, but the way the enclosure is made I cannot connect the subs together internally within the enclosure without running the wire through the middle of the vent. So I just wired them individually and connected them outside the enclosure before the amp.

 

[mhsnolie08 10+ year member]

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices. That's the link to the box that I bought.

 

[Gregulate 10+ year member]

Hmm, how are you doing that? The amp only has one set of speaker terminals? Can you take a pic of your wiring setup to the amp and indicate how they are wired to the speakers?

 

[mhsnolie08 10+ year member]

http://i1246.photobucket.com/albums/gg603/mhsnolie08/A036EC53-C6E7-401D-B58F-BAF9A0D7F8D1.jpg. just spliced and wired to the single channel of the amp.

 

[skylineTT 10+ year member]

So the enclosure has a divider in the middle im assuming.

Okay so you believe that each is internally wired down to 2 ohms. Then you are paralleling them to 1? or are you wiring series outside the box to jump them to 4? That amp isn't worth a crap so if you have the gain up enough to push the subs, you're clipping the fuuudge out of them. Check each subwoofer at their terminal at the box with a digital multimeter to see what they are actually wired to (since you don't want to take them out of the box to check).

 

[skylineTT 10+ year member]

http://i1246.photobucket.com/albums/gg603/mhsnolie08/A036EC53-C6E7-401D-B58F-BAF9A0D7F8D1.jpg. just spliced and wired to the single channel of the amp.

K that is parallel (those wires are too thin btw). If both subs are internally paralleled, you're running a 1ohm final load. That amp will put out around 180w at 2 ohms and it isn't 1ohm stable! You need a good 1ohm stable amp.

 

[mhsnolie08 10+ year member]

I don't mind taking the subs out to rewire them, but it seems strange that one sub would work fine with the setup and the other would clip. It seems to me that both would be having the same problem if the amp were the issue.

 

[Gregulate 10+ year member]

So the enclosure has a divider in the middle im assuming.
Okay so you believe that each is internally wired down to 2 ohms. Then you are paralleling them to 1? or are you wiring series outside the box to jump them to 4? That amp isn't worth a crap so if you have the gain up enough to push the subs, you're clipping the fuuudge out of them. Check each subwoofer at their terminal at the box with a digital multimeter to see what they are actually wired to (since you don't want to take them out of the box to check).

That's a good call on the DMM to check the load. You can get a cheap one from Harbor Freight, if you have one near you. Or you can order it online and it works great for tuning your amps, too. This is the one I bought: Digital Multimeter - 7 Function, w/ Backlight