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Subwoofer damping

I didn't no whether to post this in the speaker or tech forum, but I'll ask my query.

I have a very large subwoofer which has 2 16 inch drivers. I fired this baby up today after having it in storage for many years. I played a reference recording of Frederick Fennell's Pomp & Pipes. Well I set the crossover pots at 10:00, 6 being the lowest and 5 highest. Everthing was ok till there was some low and I mean low frequency with plenty of dynamics. I could hear the drivers make a girgle sound that came out the 4 vents in the cabinet.

I can't recall if I've heard this before and I'm thinking that I need to add additional damping material. Doe's anybody supply speaker wool anymore? I can't imagine overdriving this thing....I think my house would collapse...so adding more material seems might help. Any speaker tech's with answers would be appreciated.

Roger
wavetrader
david99
1,467 posts
 
"I think my house would collapse"
Do pictures on your walls and other items in your room vibrate when you use the sub?
I have a treated room,but when I added a sub it shook the room.
Problem fixed when I got my sub up off my carpeted floor with large cones.
shadorne's avatar
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shadorne
7,477 posts
 
It sure sounds like you were overdriving it from the way you describe the sound.
wavetrader OP
260 posts
 
I have a Velodyne also and that rattles all the dishes in the house. My big sub....sounds different...as instictavley you look around and say what the hell was that.

I am going to add some wool as the cabinet is about 40+ cubic feet and I don't think there is enough material in it. It could have been overdriven but I think not..but my mono amps will output about 1800W each. Kinda overkill.
audiokinesis
2,737 posts
 
Forty cubic feet? Wow.

Without knowing the parameters of your woofers, I'll just toss out the possibility that your box is too big. Can you tell us what the woofers are, and perhaps even what the port tuning is (or what the port dimensions are)?

If those are high-efficiency woofers that don't have a lot of excursion, at low frequencies you can exceed linear x-max with less than ten watts input. If your woofers are going into over-excursion, additional damping material won't help.

By the way, you used the correct term - "damping" instead of "dampening". The latter is what happens when you spill your drink on the sub.

Duke
dealer/manufacturer
wavetrader OP
260 posts
 
Audiokinesis

They are Scanspeak 16's. I don't know the model but the sub was built in about 1992. They have 2 scanpeak vario vents on either side. The box is about 20"Wx48Lx56H. I talked to the designer years ago and he mentioned that they needed more damping material. There were 2 of these made and were used in a resturant/disco-bar. They would litterly shake the whole building like a earthquake. When I had the cabinet sent to my cabinet maker the sub was dissasembled so I don't think enough material was put back in.
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