subwoofer buzz - how to eliminate it

@grislybutter 👍

Mike

@ditusa great article thank you!

@grislybutter Wrote:

@ditusa sorry for my stupidity, how do I overdrive it? 

I am not setting the volume on my amp high, just medium. The gain setting on my sub is at 50%

Ok, loudspeakers can sustain two kinds of damage thermal, and mechanical. The noises you describe in your first post sounds like it's mechanical noise.  The 10'' driver is reaching it's mechanical limits. That's what I meant by overdriving the subwoofer. Example, excessive woofer excursion can cause the noises you were describing and also high distortion. Just a guess, maybe your trying get to much low frequency, bass energy out of a 10'' subwoofer with a small box or maybe get two subwoofers would give better performance then one. Also, a woofer's speed is determined by it's frequency not it's piston diameter. See article below 4 - Cone Area Vs. Displacement: 😎

Mike

https://sound-au.com/subcon.htm

@ grislybutter

I'm the same hardwood floors on concrete slab I have two SVS Ultra subs with upgraded plate amps 1,200 RMS watts, 4,000 peak They weigh 90lbs each I did install the SVS Soundpath isolation feet My subs don't vibrate, but my house sure does  :  )

 all you need is the Auralex

and 

fix the sub to the floor

are they conflicting suggestions?  My floor is pretty rigid, hardwood on concrete. 

You do not want to isolate the sub from the floor. You want to do exactly the opposite which is fix the sub to the floor. This is what spikes are for. Use three, two up front and one in the rear. Trying to isolate a sub from the floor is folly. Bass waves are very powerful. If you have a bad floor that resonates it will do so even if the sub is mounted on the ceiling. If the floor is that bad the system need to go in a room with a sturdy floor. Spiking the sub to the floor keeps it from shaking so much. Any shaking or vibrating is distortion. 

forget the springs. all you need is the Auralex.

@ditusa sorry for my stupidity, how do I overdrive it? 

I am not setting the volume on my amp high, just medium. The gain setting on my sub is at 50%

@grislybutter Wrote:

At low frequencies, it vibrates, like it wants to fall apart. 

Just a guess, sounds like you are overdriving the sub.

Mike

@Grislybutter

Doubt that was it, but always good to tighten lose screws especially on a sub woofer

@jrwaudio exactly.... since I swapped the board in it, 2 out of 8 were loose

This may be a long shot but check the mounting screws for the drives I did this for my two powered subs and was surprised how many were lose Hey I do the same for my tower speakers 

@grislybutter Sure, happy to try to help. The Nobsound are going to be more classy looking than the Auralex platform. They are brushed aluminum with some shine to them, and when the springs are compressed about halfway as they should be (no more than halfway), I think they look really nice. And with the inserted black foam earplug mod, you can expect them to perform in vibration isolation better than the more expensive foam-based platform.

thanks @gladmo I wish there was one platform for all these, there probably is, for big $$$

My only issue with the springs is the height/look but if it works, fine.

@grislybutter I previously suggested both the Nobsound springs and the Auralex Subdude in part because the Nobsound feet have free 30-day returns, so you can decide if any additional isolation benefit is worth it to you. They isolate in a different way than the foam on the Subdude, so it will have additive benefits; neither solution being perfect by itself. They are very effective and inexpensive. The point made above about using three feet vs four only applies to spikes, not spring loaded feet. Lastly, the Nobsounds perform best with a foam earplug stuffed inside of some of the springs for a damping factor. Best of luck

all you need is the Auralex.  the sub, including the feet, will sit on top of the platform.  simple stuff.  it keeps the sub from radiating onto the floor, which brings all kinds of issues, like rattling floor boards, etc.  it works very well for me, i have 2 JL Audio subs that sit on the platforms.

@fred60 I am very inclined to try it, is it just a piece of foam with a piece of mdf on top? Do I need something between the sub and the platform, like springs?

hopefully you can fix the buzzing noise.  but you would definitely benefit from having a Auralex Sub-Dude-II isolation platform for the sub.  It isolates the sub from the floor.  great, inexpensive ($60) product that works.

@mijostyn I replaced the board in it and I probably need your tricks to make it tight. I may not have put it back together properly. 

@grislybutter , I have been building subwoofers for 40 years and I am the master of buzz/rattle elimination. 

First is to make sure the buzz is coming from the woofer. The worst buzz I ever had turned out to be coming from my theater screen but darn if it did not sound like it was coming from the sub. Get rid of any extraneous parts like grill cloth frames. Mount the sub on three spikes not four! Make sure the driver's screws are tight. Most drivers are mounted on a gasket. I mount mine on silicone caulking. I think it works better. You can still get the driver out but it will be a little more difficult. I use a trim tool (automotive) to pry them up. Lastly is check the driver. Dust caps are frequent offenders. It can be hard to determine but if you tap the dust cap lightly you should hear a thud not a click. If it is suspect run some thin cyanoacrylate glue around the edge of the cap. It will run under by capillary action. Just a little! you do not want to glue your voice coil in place. Next is gently push on the cone with your fingers surrounding the dust cap to push it back and forth. If you hear or feel any grinding noise the driver is bad and you will need a new one.

Check out Primacoustic Recoil Platforms. I have them under each of my three subs.They work best flat against the bottom in between the feet.Not expensive and they're returnable No more rattles and tightens the bass significantly.

I see this as a design failure. In my own design from 20 years ago and  which is downward firing, I have NO BUZZ or vibration. I KNOEW that with Bass frequencies that the BOX must be stable and weigh enough to prevent vibration @ frequency.

Of course my BOX (case) is 1/2 in PVC and weights in at about 80 lbs.

You can easily place your favorite family photo on top and never worry about it sliding off the top.

I have the svs ones on my living room sub. Without it pictures on the wall would rattle with it no rattle.

These get great reviews and are very reasonably priced. I'm thinking of getting some.

https://www.svsound.com/products/soundpath-subwoofer-isolation-system

It is placed on a wooden floor on rubber footers.

So why is it 'vibrating like it wants to fall apart' straight out of the box.

It's obviously faulty.  Take it back.

“More rubber”? I definitely had a chuckle there.

Bingo!

You might also consider moving sub to a less excitable location in the space.

thank you all! I moved it to the side, by the wall, and already sounds better.

Moving the sub out of the corner may also improved the sound of bass in your room. In his great series of videos, Art Noxon of ASC talks about the high and low pressure areas in the room: standing waves build up along wall/wall, wall/floor, and wall/ceiling intersections, corners being the most problematic. ASC even makes a bass trap for use under subs, which sounds counter-intuitive but actually isn't.

It's in the corner so I will move it, turn it sideways, try the simple things first.

Well, it could be that the sub is particularly badly placed for that particular frequency.  First just try moving it more into the room as an experiment, see if it not only stops shaking but also just sounds better. :)

@grislybutter Turning sideways may or may not help. You'd have to try it. Raising the height using a platform helps whether it's front or downward firing. Personally, I wouldn't bother with the slab, even though it's probably a good solution. I would just put the Nobsound springs on top of an Auralex Subdude platform for excellent isolation and a little height, and also play with placement if you are so inclined.

Convert to front firing. 

@gladmo Or I could just turn it sideways, it was meant to do that, I am looking for a clean and simple fix

@noromance what's the WAF of the slab? I would have to submit designs and as-builts for approval

Also consider placing a 24" square paving slab on the floor. Use pads or spikes under slab. Then put sub on springs on the slab.

You might also consider moving sub to a less excitable location in the space.

@grislybutter I initially missed your comment that it's downward firing.  If it were me, I would also use a subwoofer platform with the Nobsound feet on top of it to get the sub raised further above floor level. This combo together will give you cleaner sounding bass and should probably help with the rattling or whatever it is.

thanks @gladmo 

I was looking at different ones on amazon, I will try this one

I use Douk Audio Nobsound isolation feet, which uses springs, under my sub. If your sub isn’t falling apart at the seams, that should help. $30 for a set of 4

You can buy on eBay from the manufacturer here