chuffing noise from cone normal?

[Bevan]

i got my first sub ever yesterday, a dynaudio 250, on loan from the shop.

its a small sub, 1 cubic foot. and -3db at 29hz according to the specs.

when i play a heavy bass line though the sub(without main speakers engaged), i can hear noise from the sub starting at about 80db(measured at my lisning possition 6' away), and and at 90db the noise is audible from where i sit.

its not knocking or popping or anything so alarming, more like the 'chuffing' sound that one hears sometimes from a bass reflex port. but this is a sealed sub and the noise seems to be comming from the cone. its a vibrating sound, but more like the air is vibrating than anything machanical.

is this common? am i driving the sub too hard.(it may be a bit small for my 5.5mx4,4m room)

the sub does seem very 'muscal' and intergrates flawlessly with the dynaudio 52 fronts. i'm considering buying it, but am thinking maybe i need two, or the bigger model if i really want to crank it?

thanks for any input

b

 

[j_garcia]

It sounds like the driver is damaged - could be a burnt voice coil, but let's hope that isn't the problem. If you lightly push the cone in, does it make the same type of noise? Could also be a torn surround.

A local guy had a similar problem with his SVS, and it turned out to be loose screws and the driver was simply vibrating in the cabinet. SVS replaced the driver for him anyway, no questions asked. How big is your room? Is this for music only? If not, I'd seriously look for something that has better extension than 29Hz.

 

[Nick250]

I know when I listened to my HSU VTF 2 all by it's self right after I purchased it it sounded horrible. Strange sounds coming from it that sounded nothing like music. I called my local B&M to say I was going to return it. The guy at the store was truely perplexed and said "nobody had ever returned a HSU". Anyway once I got it set up properly it has sounded wonderful for both music and movies for the past 4 years. I have the volume on the sub set at 8 oclock and that is all I need for LFEs and music. Speakers are Paradigm Studio 20s set to small crossed over at 60 HZ. I guess the point of my post is that listening to a sub by itself does not tell you very much.

 

[Sheep]

Try adjusting the phase if the subwoofer has it, that might help it sound like bass. Other then that, it must be internal, try, if you want, taking the driver out of the box, and see if you can find the source.



The Sheep

 

[Bevan]

thanks for replies.

no sound when i push in cone. room is 4.5 x 5.5m. its for music mainly.

i have the volume at 12 o'clock, plus the denon 2200's +10db engaged. this does seem higher than most peoples settings.

i hope that there is something wrong with it, and if i buy one(not this one) it wont have the same problem. when i bought my audience 52 fronts the ones i borrowed from the shop to demo had port chuffing that the pair i bought did not. obviously demo equipment gets abused somewhat.

cheers

b

p.s in-room extention is 26hz

 

[mulester7]

I guess the point of my post is that listening to a sub by itself does not tell you very much.

.....very good, Nick....when I am doing serious listening to my subs to find not only levels, but all important sound quality, I have the mains and rears barely up, to give full-range overall tonality reference to the subs, with the subs popping at normal volumes....when I get the subs where I want them, I bring up the fronts and rears to matching levels......