SVS SB2000 bottoming out? Expecting too much?

samtl

Novice Member
Hi All,

Excited to test out my new subwoofer I put on 'Ad Astra' and turned the volume to around -10db reference. A few scenes, which admittedly are heavy on bass with rockets etc, caused the subwoofer to rattle past it's comfort zone and create a worrying rattle as it 'bottomed out' (I hope this is the correct term!)

Am I expecting too much? I have run Audyssey and it is set at around -5db. The room is not large at around 2000sq ft. Is there anything I can do to help the situation?
 

paulst10

Distinguished Member
Are you running the sub hot at all? Was it a flapping sound or a clacking sound? (the latter would be bottoming out) Either way your sub does have protection built in but it could just be it's not run in enough for a heavy hitter like AD Astra from the off?

Was it the Atmos version or the DTSMA? The Atmos AD Astra hits hard around 20-50hz..

 

samtl

Novice Member
That's a great response, thanks. It was the ATMOS version in fact.

Sorry - what do you mean by running the sub hot? It's turned to half gain on the back of the sub amp and I've run audyssey. then added around +4db to the subwoofer output via the main AV amp.

From what you described, I'm pretty sure it was a clacking sound on extremely loud/ powerful scenes, like the driver was over extending and hitting it's physical limits.

It's fully run in (it's second hand/ year old, hence my concern whether it was normal).

Thanks!
 
Last edited:

paulst10

Distinguished Member
That's a great response, thanks. It was the ATMOS version!

Back to basics: what do you mean by running the sub hot? It's turned to half gain on the back of the sub amp and I've run audyssey. then added around +4db to the subwoofer output via the main AV amp.

From what you described, I'm pretty sure it was a clacking sound on extremely loud/ powerful scenes, like the driver was over extending and hitting it's physical limits.

It's fully run in (it's second hand/ year old, hence my concern whether it was normal).

Thanks!
Yeh adding the 4db indicates you're running the sub 'hot'. By all means 4db isn't a lot but for a movie that's already hot, it might be a bit too much.. Do you recall any timestamps where it caused the problems? I'll post the heatmap below so you can see if it corresponds to what you heard, but I can see there's a few bits that could be problematic for smaller subs (around 28m, 34m an 49m, and possibly a few areas after those)

Just concentrate on the right half of the graph. Timestamps are on the left, frequency (0-40hz) along the bottom, the white parts are the hot areas where this probably happened..

 

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