Alpine Type R 12" acts weird in a ported enclosure

Elmadus

CarAudio.com Newbie
Hiya there! 

I'm fairly new to car audio and i have a problem with my sub, which i didn't seem to find an answer by "googling" 

So i have this Alpine 12" Type R 2 Ohm DVC sub which i got used. I play some tunes and it moves unnaturally when it's on a ported box or by itself without an enclosure. The sub looks like its only pushing inward and bouncing back up slowly

But put it in a sealed box and it plays just fine, sound great, alot better than in a ported box. 

Could this be that the sub has been used in a sealed box during it's break in period so the suspension only works properly in a simular enviorement, a sealed box. 

Or is there something else that could cause the problem? I'll post some videos from the sub if requested :) Thanks in advance! 

 
I suspect that its your ported box. It has nothing to do with being in a sealed box during break-in. Is it prefab that came with your sub when you bought it used? The sub will act different in different boxes especially from sealed to ported. You’ll notice the sub will move less when it’s playing near tuning frequency. 

 
check the wiring in the ported box.  sounds like the wires are reversed 

 
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I suspect that its your ported box. It has nothing to do with being in a sealed box during break-in. Is it prefab that came with your sub when you bought it used? The sub will act different in different boxes especially from sealed to ported. You’ll notice the sub will move less when it’s playing near tuning frequency. 
The box is a custom one. It might be that the box is just wrong for the sub. But it also does this odd movement without the box. 

check the wiring in the ported box.  sounds like the wires are reversed 
Oh, forgot to mention, changing the polarity on the sub reverses the movement. So it looks like it's only pushing outward. 

 
What amplifier are you using?Model # and brand?Have you checked each coil on the sub to see if its within limitations with a DMM(Digital Multimeter or a decent multimeter)? What are the readings for each coil? Have you pushed down on the sub back and forth easily to see if any scratching or rubbing noise/issues? Could be a wiring issue, or a bad sub as well.What are the measurements on the ported enclosure?Type R subs bang in just about anything you put them in from my experience. They should be in a ported enclosure to get the most out of them.Wiring diagram for a DVC2 ohm sub woofer

https://www.the12volt.com/caraudio/subwoofer-wiring-diagrams.asp?Q=1&I=22

 
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The box is a custom one. It might be that the box is just wrong for the sub. But it also does this odd movement without the box. 

Oh, forgot to mention, changing the polarity on the sub reverses the movement. So it looks like it's only pushing outward. 
Do you know what the specs of the ported box are? I think you're gonna have to show us a video of this.. You say it still does this free air but looks perfectly fine when sealed.. How does it sound in the ported box then? 

Check this video out.. this is an example in real time how it sealed differs from ported in excursion. Skip to 6:00 to see 



Does it look like this when it moves? or completely off? 

 
The box is a custom one. It might be that the box is just wrong for the sub. But it also does this odd movement without the box. 

Oh, forgot to mention, changing the polarity on the sub reverses the movement. So it looks like it's only pushing outward. 
Sounds like with this kind of answer, its possible that a Re cone may be needed for the sub??Investigate at the coil and cone area for seperation

 
Had a L710 that separated at the joint between coil/cone... the way it's built it had a terrible death rattle and moved one way under power but not the other. Looked closely at it out of the enclosure and was able to epoxy the thing back together, now sounds just fine.

It was a bear to do and messy but worth the trouble... looks like doo-doo but who cares?

El6CfHY.jpg


Might be worth investigating... only cost $6 and a trip to Walmart to fix, and has lasted 2 years so far.

 
What amplifier are you using?Model # and brand?Have you checked each coil on the sub to see if its within limitations with a DMM(Digital Multimeter or a decent multimeter)? What are the readings for each coil? Have you pushed down on the sub back and forth easily to see if any scratching or rubbing noise/issues? Could be a wiring issue, or a bad sub as well.What are the measurements on the ported enclosure?Type R subs bang in just about anything you put them in from my experience. They should be in a ported enclosure to get the most out of them.Wiring diagram for a DVC2 ohm sub woofer

https://www.the12volt.com/caraudio/subwoofer-wiring-diagrams.asp?Q=1&I=22
The amplifier i'm using is a Alpine PDX 1.1000. It's bit overpowered, but i adjusted the gain so it won't pop it too easily. Haven't checked the coils yet, but i will . The sub doesn't make any scratching or other weird sounds when i push it down. I also wired it so that the amp is under a 4 Ohm load. 

On 8/19/2018 at 7:39 PM, blazian87 said:

Do you know what the specs of the ported box are? I think you're gonna have to show us a video of this.. You say it still does this free air but looks perfectly fine when sealed.. How does it sound in the ported box then? 

Check this video out.. this is an example in real time how it sealed differs from ported in excursion. Skip to 6:00 to see 


The subs completely off when in a ported enclosure. The quality is bad and doesn't thump as much. In a closed one it plays well as in the video. 

 
Had a L710 that separated at the joint between coil/cone... the way it's built it had a terrible death rattle and moved one way under power but not the other. Looked closely at it out of the enclosure and was able to epoxy the thing back together, now sounds just fine.

It was a bear to do and messy but worth the trouble... looks like doo-doo but who cares?



Might be worth investigating... only cost $6 and a trip to Walmart to fix, and has lasted 2 years so far.
Hmm, maybe there might be something off with the cone structure. I'll check it out and post about the results afterwards

 
This is called cavitation. It is the result of too much power at frequencies above tuning, for the amount of airspace the driver is in. You will need to either scale back the power at those frequencies by adjusting down the low pass crossover point or by lowering the overall gain. Otherwise, you will need to shrink the volume of the enclosure to offer better damping (cone control) if you wish to continue with the current power levels. This will change tuning but you may not mind.   

 
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Hey, i think i found the problem. (sort of) 

So after trying out the system with different components, it seems that the amplifier is the cause of this odd subwoofer behavior. 

I tried a different sub on the system and it also had this one way moving issue with the PDX 1.1000 amp. After i tried a different amp altogether, both subs played normally in the ported enclosure. 

Can't think of any reasons why the amplifier does this, seems that i'll have to get a new one for the Type R. Here's a video showing the movement as it plays (sorry for the lacking quality?) Thanks anyways for trying to help! 



View attachment VID_20180822_210804.mp4
 
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