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I need help to eliminate a rattle sound from the speaker!?  

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kanaaudio
(@kanaaudio)
Active Member Registered
Joined: 2 months ago
Posts: 18
25/08/2020 2:41 pm  

Hello!

I would greatly appreciate your help!

I am getting a rattle sound when hearing songs with deep bass notes. The rattle seems to come from only one of the drivers and it only appears when the volume is turned up quite high and only on songs when quite low bass notes. And mostly on the drum beats. I kind of sounds like something hitting the thin moving speaker part!? I have read that air leaks also can sound very similar.
I find it pretty impossible to record for you guys to hear, but for example this song, Vertical Horizon - Evermore, has quite low bass notes after about half a minute.

As I said, the rattling sound seems to only come from one of the drivers (the drivers are Dayton Audio ND91-8ohm and brand new).

I haven't been able to identify any air leaks. The box is made of concrete and the connections on the back are sealed completely tight, I think, from the inside with glue from a glue-gun. I don't feel any air being pushed out when the music plays. The drivers themselves are screwed to the front panel and also glued all the way around with glue from the glue-gun. I have used damping material within the box and I have used gasketing tape around the edges before screwing in the front panel.

I don't believe the rattle sound comes from any wires being pushed around, as I have stuffed the box with the poly damping material.

I have tried to unscrew the front panel and play the song mentioned above on high volume with "free" air around the drivers. The rattle sound is still there, though not very present compared with the rattle from the closed box. There is a wire from each of the poles of the driver going to the center of the driver (you know this, of course) - I am wondering if these wires are being hit by the moving parts (the drivers move quite a lot with this song)??

Or I am wondering if this is just the limit of the speaker drivers? Or if I haven't fastened them good enough (if glue-gun is a bad choice)? Or if the gasketing tape is not good enough to use, when the front is only being held down by 2 screws?

I have no idea what causes the problem - I have experienced this problem before (I have built this one more than one time).

My setup is this :

IMG 4102 1

Speaker driver units ; Dayton Audio ND91-8ohm
Amp; Dayton Audio KAB-250v3 
Gasketing tape ; Universal foam sealing tape 3 x 10mm from soundimports.eu

Do you guys have any ideas?!? Thanks in advance!

Best regards,

Martin


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123Toid
(@123toid)
Illustrious Member Admin
Joined: 3 years ago
Posts: 980
26/08/2020 12:57 pm  

That is a hard one.  Rattles can be a lot of things.  If it is only one of the drivers, than it is probably one of two things.  Either that driver is bad or you have a wire vibrating in the cabinet.  Don't get me wrong, there can be more than just that, but those are the two msot likely culprits.  Do you have any poly fill or pillow stuffing around?  I would first stuff the enclosure with some of that.  Make sure to "wrap the wires so to speak, so the are not resting against the cabinet or driver.  See if that helps it.  If not, you can also disconnect the left and the the right speaker, make sure it is only occuring on one of the drivers.  Let us know what you find. 


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kanaaudio
(@kanaaudio)
Active Member Registered
Joined: 2 months ago
Posts: 18
27/08/2020 4:03 am  

@123toid thank you for your reply. I will pursue the two options you have given me further - try to change the driver and/or secure the wires.

I did stuff the enclosure with poly fill. But I might have underestimated the movement of the wires at high volume. I did not secure the wires specifically away from the enclosure or drivers, because I figured the poly fill would keep them in place.
I will approach this with more of a OCD perfectionism and see if the rattle is reduced.
Bear in mind that I also experienced very little rattle when I had the front removed from the enclosure, with the drivers still attached to it

Another thing I was wondering is, that in my trial and error I tried covering the whole in the back of the speaker driver with my finger, while playing high volume. The blocking of the air sounds a lot like the rattle, so I wondered if the polyfill somehow could interfere with this?

I will post what I find.

Thanks again!

 


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kanaaudio
(@kanaaudio)
Active Member Registered
Joined: 2 months ago
Posts: 18
18/09/2020 3:56 am  

@123toid I just wanted to give you (and others) an update on my findings. I think the problem was air leakage. I did some additional research and read on more than one occasion that air leakage would sound exactly like rattling wires, if the enclosure is airtight, but not airtight enough to keep the air inside on the big pushes from the drivers.

I used additional gasketing tape around the front panel to make sure that all connections was sealed properly, and that seemed to solve the problem.

Thanks for the help!


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123Toid
(@123toid)
Illustrious Member Admin
Joined: 3 years ago
Posts: 980
18/09/2020 4:03 am  

@kanaaudio

That is great to hear!  Thank you for updating us.


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