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-   -   Sunfire Mark IV Sub rattles (https://www.avsforum.com/forum/113-subwoofers-bass-transducers/799317-sunfire-mark-iv-sub-rattles.html)

SJHT 02-02-2007 02:40 PM

I've noticed that my Sunfire True Sub Mark IV started to rattle. Listening closely (my head next to the sub), it was coming from the side which has the passive woofer (left side from the front). So, I went ahead and removed all the screws and took it out. Rattle stopped. I could put it back in while the sub was running and hear the rattling inside the passive woofer startup. Therefore, it seems to be coming from this part. I went ahead and ordered a new part which wasn't cheap. Is this common? I'm using the sub without the passive woofer at this point until I get the new one which sunfire shipped out to me. The unit is out of warranty. I'm hoping that replacing this part fixes it, but seems strange to me. Thanks. SJ

robbroy 02-02-2007 05:05 PM


I'll be curious if the replacement part works. If it still rattles, obviously you'll want to send it back. If that is the case, you haven't got much to lose, so you might want to try sealing the passive radiator (the old one) to see if it goes away. If you have the radiator out right now you are running the sub almost like it's free air with such a small enclosure and such a short and wide "port".

If you don't mind me asking, how much did they charge for a passive radiator? Strikes me as something that shouldn't cost too much, but your post makes it sound like it was a pretty penny.


SJHT 02-03-2007 07:05 AM

It was $130! This has been a great sub and worth fixing (for me). The passive radiator has baffles in it. Not sure exactly what is rattling. It is really looks to be a solid component. If the new one rattles, then it goes back and I'll have to figure out my next steps. What do you mean by "sealing the passive radiator"? Thanks. SJ

robbroy 02-03-2007 08:46 AM


I'm just wondering if air escaping around the edges of the radiator might be causing the rattling (grabbing at straws).


SJHT 02-03-2007 12:53 PM

I looked at the part and it looks completely sealed. Actually fairly high quality all around on it. Not sure what the issue is with the passive radiator. Hopefully the new one will work... Thanks for the feedback. SJ

TheEAR 02-03-2007 03:22 PM

To answer the question I IT COMMON. No

I had almost all Sunfire subs since the Mark II came out and none had a problem with a PR or the woofer.And I blasted them,tortured them...anything lesser would fail.The woofers and PRs used by Sunfire are very sturdy and built to last.

I would check for air leaks.As a tiny hole may give you the impression you have a loose part.Inspect the PR.

You are running the sub with the active woofer only! Did you seal the hole left by the PR? As open,you have cancellation galore.Check for any cables that may touch a membrane and cause a rattle or buzz.

Darin 02-03-2007 07:58 PM

Interestingly, my Sunfire (original True Sub), developed a sort of rattle sound, but I thought it was coming from the active driver. Wasn't really a rattle, more of a "sticky" sound. There's a bit of a bump in the middle of the active driver (don't know what's behind it), but the rubber-like material on the face of the driver doesn't seem firmly attached to the surface of the driver near this bulge. To ME, it sounds as if the rubber is flapping against the driver at certain frequencies. Now if yours is making a sound that resembles more of a higher pitched ticking sound than a rattle, maybe we have the same problem, and maybe mine IS the PR and not the driver.

SJHT 02-04-2007 07:40 AM

You may be right. It actually is more of a flapping sound, but coming from the passive driver. It is easy to hear. Since I have it removed, if I put it back in as it gets sealed, it starts the flapping noise. I am running without the passive component at the moment. Not ideal, but it does work. I turned the sub down a bit. Part should arrive this week.

SJHT 02-06-2007 05:18 PM

New passive radiator arrived today from Sunfire. Installed it and it works PERFECT. Good as new. SJ

robbroy 02-06-2007 05:48 PM

That's great news! $130 well spent.


Bakermd 12-17-2019 04:54 PM

I’m experiencing a tinny sound, as if a piece of tin came loose inside the active driver of my MK II. When taking it apart I noticed that two of the screw anchors had come loose at some point in the past and were stuck to the active driver magnet... this fixed a different issue I was hearing at louder volumes, but there is still something dancing inside the active driver.

Any thoughts? Seems like this could be an expensive repair.

Never owned a Sunfire before this one, and bought it second hand. It has been sitting for a year at this point, and wasn’t heavily used when I first got it (another sub did a better job for the room) but I experienced this one as a younger man and know how awesome it is, and want to put it to use in a properly sized room! :-)

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