Sub suddenly bottoming out?

[Hi Ho]

I built my Rythmik DS1500 sub years ago and it has been an amazing sub. I popped in a Blu-Ray last night and during the very first preview I hear this:

https://www.youtube.com/watch?v=xR1fL-_hFyo

That noise is coming from the sub, not anything else rattling. I tried some other movies that I have watched before at the same levels and the same thing happens. Is my sub done for? Why would it suddenly start doing this?

 

[TLS Guy]

I built my Rythmik DS1500 sub years ago and it has been an amazing sub. I popped in a Blu-Ray last night and during the very first preview I hear this:

https://www.youtube.com/watch?v=xR1fL-_hFyo

That noise is coming from the sub, not anything else rattling. I tried some other movies that I have watched before at the same levels and the same thing happens. Is my sub done for? Why would it suddenly start doing this?

The driver has suffered some sort of mechanical catastrophe. I would suspect either the accelerometer has come loose or there has been a cone voice coil separation.

Take out the driver and inspect it.

 

[Hi Ho]

I completely forgot about this thread. I posted this right before I went on vacation. I think I will take the driver out today and look at it.

 

[AcuDefTechGuy]

The cat jumping at the sound of the sub "clipping" is priceless.

 

[Hi Ho]

Haha yes the cat ran into the frame just as I turned on the camera.

I attempted to remove the driver today but it appears that I siliconed it in when I built the sub. I cannot get it to budge. I can recreate the rattle sound though:

https://www.youtube.com/watch?v=kEnkfZ8CGgw

 

[TLS Guy]

Haha yes the cat ran into the frame just as I turned on the camera.

I attempted to remove the driver today but it appears that I siliconed it in when I built the sub. I cannot get it to budge. I can recreate the rattle sound though:

https://www.youtube.com/watch?v=kEnkfZ8CGgw

The driver needs reconing. Lay the sub, speaker face up. Poor some alcohol around the outside of the chassis. Keep it wet with alcohol for 12 hours or so and it should denature the silicone. Then with a bit of brute force and ignorance it should come out. In any event silicone almost always yields to superior force. Some small tire levers will help.

Use something like this.

The other thing you can try first is a paint can opener. They will give you one for free at the hardware store.

 

[Hi Ho]

Part of the problem is that I constructed the bottom of the box with two layers of 3/4" MDF and the driver is 3/4" inset with very little gap leaving little to no room to pry. I may try the alcohol trick.

 

[TLS Guy]

Part of the problem is that I constructed the bottom of the box with two layers of 3/4" MDF and the driver is 3/4" inset with very little gap leaving little to no room to pry. I may try the alcohol trick.

At the moment you have a useless sub. So if you deface your carpentry so be it!

 

[Hi Ho]

It's definitely not useless. The noise only occurs during loud passages when I really crank it up for movies at nearly reference level. The sound is great at normal listening volumes and I cannot reproduce it with music.

 

[TLS Guy]

Well when you tap that cone, something is not right and I suspect cone voiced coil separation starting. I suspect you are not too many explosions away from destruction.

 

[fuzz092888]

It's definitely not useless. The noise only occurs during loud passages when I really crank it up for movies at nearly reference level. The sound is great at normal listening volumes and I cannot reproduce it with music.

I agree with TLS, that sub is useless. I had a sub driver make a noise like that before. Sent it back for warranty repair and the company I bought it from told me that the VC was burned and that if I had kept playing it, it would eventually fail and possibly totally separate. The more you use it, the worse it will get and the greater chance something bad will happen.

 

[Hi Ho]

Has anyone dealt with Rythmik support? I'm pretty sure it's out of warranty but it would be nice if I could purchase a driver by itself. They only sell driver amp combos on their site.

 

[TLS Guy]

Has anyone dealt with Rythmik support? I'm pretty sure it's out of warranty but it would be nice if I could purchase a driver by itself. They only sell driver amp combos on their site.

I assume that driver is less then 7 years old. By Federal law manufacturers have to make every effort to keep parts available for seven years. So they have to make every effort to provide you with parts to recone that driver or repair it themselves. If they don't, then you need to notify the Federal Trade Commission.

Let us know what happens. My BS sensors are somewhat activated already by this outfit.

How were you driving that sub anyway? I think they only sell driver amp combinations, as they driver needs a limiter. If a limiter is not used it seems that driver is prone to trouble.

 

[AcuDefTechGuy]

Just curious, what amp did you use for the sub?

 

[Hi Ho]

I believe it is the Rythmik A350 that was paired with the 15" driver at the time. Looking back through my emails, it looks like I bought it in 2007. Definitely out of warranty.

 

[AcuDefTechGuy]

I believe it is the Rythmik A350 that was paired with the 15" driver at the time. Looking back through my emails, it looks like I bought it in 2007. Definitely out of warranty.

So what's next?

Passive subwoofer?

Do you know what the max power rating is for the subwoofer driver is?

I assume the plate amp had a limiter. Did you use the limiter?

 

[Hi Ho]

I did exceed the limit at least a couple times in the past when the sub shut down completely and had to be power-cycled to bring it back to life. The amp still works fine. It's just the driver that's broken.

What's next? Possibly a PB-13 Ultra.

 

[fuzz092888]

Or a rhythmik fv15hp

 

[3db]

Let us know what happens. My BS sensors are somewhat activated already by this outfit.

How were you driving that sub anyway? I think they only sell driver amp combinations, as they driver needs a limiter. If a limiter is not used it seems that driver is prone to trouble.

I'm thinking your BS sensor is totally out of whack. You may need to recalibrate it. Unless you dealt with them and heard their products, I'm afraid that all you are going on is BS speculation on your part. Time for you to reboot.

 

[AcuDefTechGuy]

I did exceed the limit at least a couple times in the past when the sub shut down completely and had to be power-cycled to bring it back to life. The amp still works fine. It's just the driver that's broken.

What's next? Possibly a PB-13 Ultra.

That makes me wonder what that driver's power rating is. A 350 watts RMS into 4 ohms amp (which is probably equivalent to 200 watts into 8 ohms amp) isn't really extraordinary power.

They need to use woofers with power rating of 3 times the amp power.