# Could my BFD settings have destroyed my sub's amplifier?



## lovingdvd (Jan 23, 2007)

Recently I turned my system only to find that the amplifier on my HSU subwoofer wasn't working. Upon inspection I found that the power LED would not come on even though I was sending it good power and fuse was just fine. I tried switching it to the manual ON position as well - nothing...

I removed the amp from the sub and sent it into HSU for service. They said that the controller card on the amp had gone bad and replaced it under warranty. However this repair certainly wasn't free - I paid for express shipping back and forth and worse had to go without my sub :explode: (should be back middle of next week).

However my main concern is whether something in my setup caused this card to fail. Because if so, then this issue is likely to resurface which I certainly want to avoid (being without my sub for a couple of weeks is NO FUN!  )

I'm certainly not an expert with REW/BFD but I'm also not a noob, as I've been using it for a year now and have done multiple calibrations with it.

I have the BFD set to use the -10db level. I have my output level coming from my AVR so that at the absolute loudest level I would ever listen to it, the deepest bass only causes a split second flicker into the red LEDs and rarely even lights up orange. I have a few big filters that remove a big peak at 30hz, as well as a couple of filters that add no more than +2 or +3 gain at a few frequencies to cover a few dips.

My subs output level (volume knob) is only turned up less than one quarter of the way, and the sub is set to run about +3db hotter than the mains (however I do use a house curve of +8 20 0 80 if that matters). I never, ever, hear any distortion or rumbling/muffling from the sub that would suggest I am over driving it. Nothing but good clean deep and tight bass.

So now I am left wondering - is it possible that my usage/configuration somehow have caused the controller card on the amp to blow? Or is it more likely that a part like that blows from something faulty with the hardware that just goes bad? My feeling from talking with HSU is that it is pretty rare for this card to fail, but apparently this wasn't the first time they've seen this.

I've had this sub and used it in combination with my BFD for about 6 months with no problems. However just a week or so before this problem occurred I upgraded my Yamaha receiver (HTR-6090) to a newer one (RX-V1800) and redid my REW/BFD work accordingly. So the timing of this does seem a little bit suspect, but certainly may just be a coincidence.

Also we recently lost power in the neighborhood with a few flickers on/off. I have the BFD and sub plugged into an APCC battery back up with surge protection. The BFD was fine. I wonder if somehow a surge in the power could have caused the controller board to fail? Probably not though - considering that it was protected by a surge protector and the BFD (which I would think would be more prone) was fine. Also the electric is somewhat prone to going out here - we've probably had 5 power failures in the neighborhood since owning this sub and no issues in the past.

However the timing here is also a bit suspect - this power failure in the neighborhood was Tuesday night. That night after power was restored I watched The Shining which does not have deep bass, so its entirely possible the sub was out then and I didn't notice. It was the following night when firing up Nine Inch Nails HD DVD that I noticed no sub - the LFE from that concert is fantastic so of course I noticed it was out. So its possible the sub amp failed at the time of the power failure in the neighborhood.

At any rate, as you can see there certainly are a lot of "moving parts" in the circumstances surrounding the amp going bad. So I'm really trying to understand what could cause this controller board to go bad. Hopefully it was hardware that just went bad and was a fluke - a one time event that I really don't need to worry about reoccurring.

However I can't help but be paranoid that something in my set up - or even in the electricity - caused the failure in which case I need to proactively address it now to prevent this from happening again.

What do you guys think? Thanks!!


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## OvalNut (Jul 18, 2006)

I think that it was probably a potentially susceptible part in the sub that got pushed over the edge by the recent electrical hiccups you've had. 

From what you've described, your setup and use of the BFD has been judiciously proper and well within reason. No worries there in my mind.

I wouldn't give it a second thought once you get your sub repaired.


Tim
:drive:


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## lovingdvd (Jan 23, 2007)

OvalNut said:


> I think that it was probably a potentially susceptible part in the sub that got pushed over the edge by the recent electrical hiccups you've had.


Thanks for the feedback. Is the surge protection provided by a typical APCC backup battery then not sufficient to protect equipment then such as this case? I had it plugged into the surge protection only socket instead of the surge+battery socket (I saw no reason to keep the sub running during a power outage). Could this have made a difference?

What other reasonable steps could be taken to help prevent this in the future? I know there are super-high end power conditioners and so forth, but it has to make financial sense (not going to buy a $1000+ power protector to cover a $500 sub, etc).


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## lovingdvd (Jan 23, 2007)

I should also have mentioned in my configuration in the original post that I also use a custom made XLR that lifts the ground to remove a hum. If you want the details on that see the last few pages in this thread: http://www.hometheatershack.com/for...at-solution-do-folks-use-dreaded-bfd-hum.html 

Not sure if this makes a difference and could have opened up a possible vulnerability leading to the amp's failure or not - but in another thread I read something that made me think it may be important to have mentioned this...


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## fibreKid (Apr 20, 2006)

I use a zero surge, it's a i bit bigger than a brick. It won't break the pocket book but it will protect against spikes. Plug your APC UPS into the zero surge.

-john


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## lovingdvd (Jan 23, 2007)

fibreKid said:


> I use a zero surge, it's a i bit bigger than a brick. It won't break the pocket book but it will protect against spikes. Plug your APC UPS into the zero surge.
> 
> -john


Thanks for the suggestion. I'm definitely going to look into this.

Am I correct to assume that somehow using a Zero Surge provides better protection than than the surge protection built into a typical APCC backup battery? If so, in what ways and is it enough to justify adding the zero surge if you already have the APCC?

Also my electrician is saying they make whole house surge protection devices he can install I guess at the main feed. This sounds like a good idea. Anyone have experience with these? How well do they work?


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## fibreKid (Apr 20, 2006)

http://www.zerosurge.com/HTML/versusres.html

Like any marketing info ... 

I had read in other forums about using the battery backup for just that and protecting the backup with surge protection. I myself have no UPS on my system. My PCs have battery back up but not my TV and such. I run my HT equip through a zerosurge.


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## lovingdvd (Jan 23, 2007)

fibreKid said:


> http://www.zerosurge.com/HTML/versusres.html
> 
> Like any marketing info ...
> 
> I had read in other forums about using the battery backup for just that and protecting the backup with surge protection. I myself have no UPS on my system. My PCs have battery back up but not my TV and such. I run my HT equip through a zerosurge.


Thanks. I just purchased a couple of these - one just for the sub and BFD, and the other for that main feed that all my other HT equipment comes from.

What is upsetting is that the back up battery people have led me to believe that I was adequately protected from surge issues. When in fact that's not at all the case, at least according to Zero Surge's marketing material. Its one thing to consciously decide not to use surge protection, but to use a product thinking you are well covered when indeed you are not is another thing altogether!

Of course you can never tell with marketing info, but at this point I'm trusting Zero Hour's story/reasons to use their products over APCC surge protection in my Back-Ups...


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