Rear port of Sub Rattling - AVS Forum
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post #1 of 29 Old 01-01-2013, 09:55 PM - Thread Starter
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I have a Velodyne VRP 12 inch sub that i've owned since 07. Lately i have noticed rattling coming from the rear port of the sub during sections of movies that have deep and powerful LFE. The woofer doesn't seem to be distorting, just the rattling that is coming from the back of the sub inside the port. What is the cause of this? and can i do something to fix this such as stuffing the port with something? Or, should i invest in a new sub altogether? Any help would be greatly appreciated.
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post #2 of 29 Old 01-01-2013, 10:02 PM
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If it's a rattling of the port tube then you need to secure it somehow, sounds like it has become loose. Maybe a little electrical tape, maybe just a wedge of sorts; open it up and see what you need to do or take it to someone who can do that for you. Probably a simple repair. Good excuse for upgrading the sub, tho. smile.gif

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post #3 of 29 Old 01-02-2013, 10:19 AM - Thread Starter
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Thanks for the reply. I stuffed a t-shirt in the port to see what would happen lol The rattling went away, but the bass lost almost all of it's definition. Any thoughts? How would i go about opening it up to see whats loose in the port? And, could it be that the sub is being pushed past it's capabilities, and that's what is causing the rattle? I'm not running the sub that hot though, but i'm really not sure at this point. Any further help would be appreciated.
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post #4 of 29 Old 01-02-2013, 10:38 AM
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Originally Posted by cknookie View Post

How would i go about opening it up to see whats loose in the port?
You probably have to pull the driver.

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post #5 of 29 Old 01-02-2013, 10:57 AM
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Originally Posted by Bill Fitzmaurice View Post

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Originally Posted by cknookie View Post

How would i go about opening it up to see whats loose in the port?
You probably have to pull the driver.

Using the correct tools help ( wink.gif ), look at the fasteners around the rim of the driver, might be a phillips or hex (and might be metric if hex, might be English measure).

Stuffing the port changes the way the sub works, thus the change in sound. Some subs even come with port plugs (usually of foam). The port is a tube inside the enclosure, so it probably came unglued or something.

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post #6 of 29 Old 01-02-2013, 11:02 AM - Thread Starter
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Ok, thanks for the advice. Just curious though, if i were to invest in a new subwoofer, what would you guys recommend for a medium sized room? I was looking at the SVS PB-1000.
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post #7 of 29 Old 01-02-2013, 12:59 PM - Thread Starter
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Update: just removed driver and looked inside sub. Nothing appears to be loose, and everything is glued in place. Is their something in particular that i should be looking for? lol Sorry about being a pain, but i'm new to this.
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post #8 of 29 Old 01-02-2013, 01:02 PM
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Originally Posted by cknookie View Post

Update: just removed driver and looked inside sub. Nothing appears to be loose, and everything is glued in place. Is their something in particular that i should be looking for? lol Sorry about being a pain, but i'm new to this.
If there's nothing loose inside then the only other possible noise source is the driver.

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post #9 of 29 Old 01-02-2013, 01:05 PM - Thread Starter
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I've heard about people taking the stuffing from a pillow and putting it inside their subs. What are your thoughts on this? and is it a fire hazard in any way?
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post #10 of 29 Old 01-02-2013, 02:00 PM
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Originally Posted by cknookie View Post

I've heard about people taking the stuffing from a pillow and putting it inside their subs. What are your thoughts on this? and is it a fire hazard in any way?

People will often apply polyfill for sealed subwoofers, but I would not do this with a ported sub, and I don't think this is really addressing your issue. Like Bill said, it could be the driver.
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post #11 of 29 Old 01-02-2013, 02:03 PM - Thread Starter
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I double checked everything inside a second time, and everything seemed tight. If the driver is at fault here, then the sub is screwed? lol would i be correct in that assessment?
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post #12 of 29 Old 01-02-2013, 02:10 PM
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Originally Posted by ack_bk View Post

People will often apply polyfill for sealed subwoofers, but I would not do this with a ported sub, and I don't think this is really addressing your issue. Like Bill said, it could be the driver.
All subs should be lined with damping, which reduces above bandwidth harmonic distortion. Only sealed subs should be stuffed.
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If the driver is at fault here, then the sub is screwed? lol would i be correct in that assessment?
It could be you're just playing it too loud and/or too low, but a damaged driver (caused by playing too loud and/or too low) is a possibility, and it will only get worse if it is.

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post #13 of 29 Old 01-02-2013, 05:30 PM - Thread Starter
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Pretty disappointed by this. I have had the sub for 5 years, but i paid 350$ for it back in 07, so this is a big letdown for me. What are your recommendations for subwoofers that are in the 4-500$ price range for medium sized rooms?
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post #14 of 29 Old 01-02-2013, 07:14 PM
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You looked inside or put your hands in there and tried to see if anything was loose to your fingers? I'm still thinking of your description as a rattling sound, but maybe that's not conveying it either. Any possibility you have something in the port tube still? Imagine if you've turned the sub in various directions you probably would know, but kids can get creative as can prankster friends....

There are many many threads discussing subs at the pricepoint you're thinking about. Usual culprits are SVS, Hsu, Epik (out of stock), Outlaw, etc. Then there are various subs on closeout sales (like the Klipsch RW12d when it goes for $299 shipped). Appears you can get the same Velodyne sub now for $249 (plus shipping?) as a refurb now http://velodyne.com/vrp-12-subwoofer-refurbished.html

ps A lot of things aren't made for the long run any more, and many consumer electronics fall in this category, too.

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post #15 of 29 Old 01-02-2013, 08:04 PM - Thread Starter
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Thanks for the reply again. Yes, i ran my fingers all around the inside of the sub, including the port, and i didn't see or feel anything that was loose. The "rattle" comes from the bottom rear portion of the sub, and i made sure to check everything in that area. I'm starting to think now that i am trying to make the sub do something it can't duplicate very well, and my standards for it may be to high. Strange thing is, is that i don't think i run the sub that hot, as my system is properly calibrated. The Gain on the back of the sub is set to the middle position with the receivers gain set to -10. To me that doesn't seem like it's being pushed that hard, but maybe i could be wrong.
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post #16 of 29 Old 01-02-2013, 09:13 PM
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Quote:
Originally Posted by cknookie View Post

Thanks for the reply again. Yes, i ran my fingers all around the inside of the sub, including the port, and i didn't see or feel anything that was loose. The "rattle" comes from the bottom rear portion of the sub, and i made sure to check everything in that area. I'm starting to think now that i am trying to make the sub do something it can't duplicate very well, and my standards for it may be to high. Strange thing is, is that i don't think i run the sub that hot, as my system is properly calibrated. The Gain on the back of the sub is set to the middle position with the receivers gain set to -10. To me that doesn't seem like it's being pushed that hard, but maybe i could be wrong.

I would turn down the gain on your sub, try to get that -10 closer to between -5 and 0 and see if you still have the issue. Are you using Audyssey? If so -10 is on the higher side...
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post #17 of 29 Old 01-02-2013, 10:12 PM - Thread Starter
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So, your telling me to lower the gain on the sub, but raise the sub level from my receiver? And -10 is what audyssey set my sub level to. Isn't -10 fairly low considering the gain goes from -15 to +12?
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post #18 of 29 Old 01-02-2013, 10:25 PM
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Originally Posted by cknookie View Post

Pretty disappointed by this. I have had the sub for 5 years, but i paid 350$ for it back in 07, so this is a big letdown for me. What are your recommendations for subwoofers that are in the 4-500$ price range for medium sized rooms?

The Epic Legend had a recent price drop to 400 dollars? Just tossing around some ideas though. That and the PB-1000. Personally though, I am going to save up and just get something under 1000. We all know it's only a matter of time if we keep coming back to this forum that we'll wanna see what the hype is about. The VTF-15H is my dream currently. Hopefully within the next 2-3 years, with the goal being 2 of them within the next 5.

I wouldn't do the Klipsch though. I'm having a similar rattling sound and apparently other people are too. I'd go with something a little better made. Might as well upgrade if you're going to get something new and you can't get this fixed. 5 years isn't bad.
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post #19 of 29 Old 01-03-2013, 12:40 AM
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The Epic Legend had a recent price drop to 400 dollars? Just tossing around some ideas though.

Good luck buying anything from Epik other then t-shirts.
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post #20 of 29 Old 01-03-2013, 01:30 AM
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Good luck buying anything from Epik other then t-shirts.

Ha, I was really really sad to see that I missed the deal and it's out of stock. I wish I could place a preorder right now! It's for the best though. I'd probably be buying something I don't need but the price seemed so nice at 400 dollars who can resist.
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post #21 of 29 Old 01-03-2013, 07:40 AM
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Originally Posted by cknookie View Post

So, your telling me to lower the gain on the sub, but raise the sub level from my receiver? And -10 is what audyssey set my sub level to. Isn't -10 fairly low considering the gain goes from -15 to +12?
No, just lower the gain on the sub a little bit, then the number Audyssey assigns will get lower and closer 0, which is what you want. If the bass is too low for your liking, then you can start raising the sub level through your receiver.
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post #22 of 29 Old 01-03-2013, 11:03 AM
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Originally Posted by cknookie View Post

So, your telling me to lower the gain on the sub, but raise the sub level from my receiver? And -10 is what audyssey set my sub level to. Isn't -10 fairly low considering the gain goes from -15 to +12?

The setting that came from the autosetup routine is just trying to reach a level that is "correct" with respect to the other speakers (and vs reference in many receivers) based on how your sub responds in room. -10 is just under four times more "power" (really voltage) in to the sub than -15 would be, but in the end it's just a matter of getting the two deifferent volume controls to add up tho the right level. Lots of folks around here like to fiddle with their sub volume controls until the receiver's sub out level is close to zero (say -3 to +3 as a generality) but it should not make a difference except in rare cases. (Some folks need a hotter input signal to wake up their subs that have auto-on, so they turn the sub down so the receiver outputs a higher level to the sub). Absent identifiable problems, any calibration should be just fine as long as your receiver is not setting the sub at the max, either plus or minus, because you don't know if max is correct, of the system just ran out of adjustment range.
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post #23 of 29 Old 01-03-2013, 11:47 AM - Thread Starter
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Thanks for the advice again guys. I think bottom line is that this sub struggles at high volume levels, and i'm looking to upgrade to the PB1000. I did a lot of research, and i'm going to give SVS a try. This will be a first time SVS purchase for me.
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post #24 of 29 Old 01-03-2013, 06:50 PM - Thread Starter
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One last question: I am currently using the Onkyo RC160 as my receiver, and for the most part have been very happy with it. If i were to get the PB1000, would this receiver give me enough power to run it well?
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post #25 of 29 Old 01-03-2013, 08:32 PM
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Originally Posted by cknookie View Post

One last question: I am currently using the Onkyo RC160 as my receiver, and for the most part have been very happy with it. If i were to get the PB1000, would this receiver give me enough power to run it well?

It's a line out (pre amp level) to the sub, has nothing to do with the amp in the receiver.

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post #26 of 29 Old 01-03-2013, 09:04 PM
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Originally Posted by lovinthehd View Post

It's a line out (pre amp level) to the sub, has nothing to do with the amp in the receiver.
Meaning the sub has its own amplifier so your receiver doesn't power it....
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post #27 of 29 Old 01-03-2013, 09:11 PM - Thread Starter
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Ok, so the sub's amp does all the work. Makes sense. Do you think different receivers affect sound quality/ sub performance in any way, or is that still 100% dependent on the sub itself.
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post #28 of 29 Old 01-03-2013, 09:14 PM
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Quote:
Originally Posted by walke108 View Post

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Originally Posted by lovinthehd View Post

It's a line out (pre amp level) to the sub, has nothing to do with the amp in the receiver.
Meaning the sub has its own amplifier so your receiver doesn't power it....

Now makes me wonder since he has to ask, just how cknookie has the sub connected?

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post #29 of 29 Old 01-03-2013, 09:50 PM - Thread Starter
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I was really just asking if different receivers affect sound quality of your sub, it just came out dumb. sorry bout that. lol
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