First DIY sub not working. Need help.

 

New member
Username: Tknob

Post Number: 1
Registered: Aug-07
I really wanted to try a DIY sub. I started with an enclosure design I found online and followed it to the letter. It called for an SVS sub driver. Got the whole thing hooked up and it isn't even audible at high volume. Lightly touched the driver and found that it is moving, but not much. Thought my amp might be underpowered so I purchased a samson S1000 which is recommended by SVS. barely any change. Thought I might have bought a bum driver so I bought a second one off ebay. Hooked it up tonight and same thing. The preamp is driving all the other speakers fine. If I hook up one of my mains to the subwoofer channel (turned the volume way down of course) I'm getting signifigantly more volume from my mains. Even if I totally messed up my enclosure shouldn't just the driver be able to make a significant amount of noise (audible at least) and be vibrating a lot? I've been using the scene from Nemo where the depth charges go off to test. I would think that at -30 db that sub should be moving a lot more. I have the sampson in stereo mode hooked to channel 1 at -20db. I was expecting that my first DIY attempt might leave someting to be desired, but am very frustrated I can't even get it so I can hear it. Any suggestions would be appreciated.
 

Gold Member
Username: Nuck

Post Number: 8239
Registered: Dec-04
Troy, what kind of preamp are you using to send a signal to the sub?
Is the connection 'sub out' or 'LFE out'?
What source are you using to the preamp, and have you tried cd and dvd?
 

New member
Username: Tknob

Post Number: 2
Registered: Aug-07
Sony E9000ES. I reset it to factory defaults confirmed that the sub channel is activated and that the gain for that channel wasn't turned down. It's labeled as woofer. It sounds like the sub channel when I run it to my main.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11053
Registered: May-04
.

Have you contacted SVS?


Disconnect the "sub" driver. Run a speaker cable that would normally feed one of your front speakers directly to the driver. What do you get?


With the driver disconnected, run the subwoofer amplifier to one of your front speakers. Plug your CD player directly into the inputs of the amplifier and use the gain controls of the subwoofer amplifier to set volume. What do you hear?



.
 

New member
Username: Tknob

Post Number: 3
Registered: Aug-07
SVS made a few suggestions and then suggested replacing the driver which I've done. They are only willing to help so much when your doing a DIY job with their driver. I haven't tried sending a front channel to the sub because I was worried about damaging the driver. I'll try that on low volume tonight. I've got a DVD player not CD, but it does have pre-outs. I haven't tried that yet. I'll let you know.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11055
Registered: May-04
.

I'm unfamiliar with the specific driver you own. If it is a dual voice coil system make certain all your connections are correct.


If you hear no music through the sub driver when connected as I instructed, remove the speaker cable and test the unit with a battery. Connect leads from the "+" and "-" terminals of a flashlight battery to the appropriate terminals of the driver. You should see and hear the driver move forward and back as you connect and disconnect the battery leads.

.
 

New member
Username: Tknob

Post Number: 4
Registered: Aug-07
It's not dual voice coil. I've tried the battery test in the past after speaking with a support technician at SVS. The battery does a good job of pushing the driver and I get much more excursion than when I'm testing the sub in my system.
 

New member
Username: Tknob

Post Number: 5
Registered: Aug-07
Here is an article that shows the driver I have and the one that replaced it (The reason I was able to get the driver cheap).
http://www.hometheaterspot.com/fusionbb/showtopic.php?tid/51164/
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11056
Registered: May-04
.

"The battery does a good job of pushing the driver and I get much more excursion than when I'm testing the sub in my system."


It should. If your amp pushed the driver in the same way as the battery, the driver wouldn't last long.
 

New member
Username: Tknob

Post Number: 6
Registered: Aug-07
I don't know what else to say about the battery test then. When I use a battery I hear a Bump sound and I see it move. When I use it on test material I feel slight vibrations and hear nothing. My mains at the same time are shaking the room. (Klipsch forte II's)
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11057
Registered: May-04
.

The Klipsch Forte's are very sensitive speakers which play loud with little input power. It sounds like you don't have the levels set correctly on your processor. Try turning down the front channels at the set up menu of the processor.
 

Gold Member
Username: Nuck

Post Number: 8263
Registered: Dec-04
Troy, it really seems like a signal path issue.
Or maybe a voltage input issue to the sub amp.

Does the sub offer speaker level inputs?

Could you try those?
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