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DIY Subwoofer /w SVS 12" driver problem


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7 replies to this topic

#1 of 8 OFFLINE   Michael Cawcutt

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Posted January 09 2011 - 02:17 PM

Hey All //

 

Been a long time, hope everybody is doing well. This weekend I had the opportunity to buy a 12" SVS driver at an estate sale. It's just the driver itself, no enclosure, amp etc ...

 

He had purchased it at an a/v shop here in Mpls. to replace a blown driver of his own. He never got around to doing so, so in mad dash to sell everything before he moved, I got it for only ... $30. :)

 

Anyway, today I take out my existing 12" driver, plug in my - & + connectors and ... nothing.

 

I obviously consider the following that this could be a dead or blown driver. He said "it works", however I don't know for sure. There are no signs of wear, tearing, etc ... The cone, foam, wiring, everything seems and looks to be in flawless condition.

 

I'm also wondering (here's where everybody's advice comes in) if I'm an under-powering or improperly powering this driver. I know that some subwoofer enclosures have 2 separate amplifiers. One, the plate amp on the back, and a second internal. Is this the case for powering this svs driver and/or svs subwoofer's in general? Looking up as much information about SVS subwoofers, I think this driver is from the SVS DB 12 series, and has a Bash 525w amp.

 

Thirdly, it has 4 connectors. Two positive, and two negative. Might be missing something here ...

 

Finally, my current subwoofer enclosure is an older Optimus I had while back in school. (hold for laughter here). It's worked great, but wanted to see if this new SVS driver would give me more punch. It's got a 100w plate amp pushing the current driver.

 

So, yes this could be dead, but IF IT'S NOT than .. do I have adequate power? Still running with my Onkyo 601 & Polk RM7's.

 

Thanks all!

 

M

 

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#2 of 8 OFFLINE   Michael Cawcutt

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Posted January 09 2011 - 03:34 PM

Hey all so I now know that it's a dual voice coil driver. I spliced a bridge wire, but no dice. If don't hear back from you guys this week, I'll bring the driver into an a/v shop to see if it's any good.

#3 of 8 OFFLINE   Robert_J

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Posted January 10 2011 - 01:13 AM

First, it's not a dual voice coil sub.  It has dual tabs on the terminals because SVS at one time used pairs of these in a sub and it made it easier to connect them.  Look behind the terminal and you will see a single set of tinsel wire leading to the voice coil.  How do I know?  I have a pair of these right now.  They are based on a TC Sounds TC2+ motor structure.  Single voice coil.  4 ohms nominal.  If you need the full T/S parameters for a build, then  let me know.



if I'm an under-powering

No such thing.  If that were true, you would have issues every time you turned the volume down.



improperly powering this driver

Could be.  What was the optimal impedance of your old driver?


Also, have you tested this driver with a multi-meter.  Testing the resistance should read little above 3 ohms.



#4 of 8 OFFLINE   Michael Cawcutt

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Posted January 10 2011 - 02:47 AM

Robert,


Thanks for your reply. Here's what I'm currently working with. My current 12" enclosure was a passive Optimus enclosure. I harvested an amp from a powered 10" Optimus subwoofer. The 12" driver has a nominal 8ohm input, 100 watts rms, 200 watts max out.


The amp that I took from the powered 10" was a smaller 100 watt plate amp.


Any other further advice into the matter would be greatly appreciated!


Still going to bring this in and have the svs driver tested, secondly wondering if I should look at buying a new amp and enclosure from parts express.


Thanks all!


M



#5 of 8 OFFLINE   Michael Cawcutt

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Posted January 10 2011 - 02:53 AM

So, if the SVS driver is 4 ohms and my small amp is 8ohm 100 watts max out, am I inadequately powering the driver? Therefore, it won't move?

edit: upon further review and investigation I think this svs driver may be blown ... :( I'm going to try the 9v battery trick, but also read is you slightly push the center/cone in and hear a "scratchy" noise, that's bad. What exactly am I hearing?


I have two other drivers here at home, current 12" and another 12". Neither of them make that "scratchy" noise when I gently push the center/cone in.



#6 of 8 OFFLINE   Robert_J

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Posted January 10 2011 - 04:33 AM

That amp may not be able to power a 4 ohm load and goes into protection mode.


The scratchy noise is the voice coil either scraping on the pole piece or the windings have come loose and there is wire running all inside the magnetic gap.  The battery test should tell you if it is blown or not.  It should move cleanly with no sound.


If it is blown, it is difficult to find recone parts.  I have the same magnet and I've been trying for a year to get it built back into a sub.  I think the guys at AE Speakers can do it.  Their old Stryke AV series is also a TC2+ based motor.



#7 of 8 OFFLINE   Michael Cawcutt

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Posted January 10 2011 - 06:09 AM

... well, the driver is dead. 9v battery doesn't lie. :(


Worth trying to have this rebuilt?



#8 of 8 OFFLINE   Robert_J

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Posted January 10 2011 - 12:15 PM

SVS sold this driver for close to $300.  If I can get a coil for my motor, I'll pass that information along to you.  Re-building a sub is easy.