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Discussion Starter · #1 ·
OK, Im dialing my BFD using test tones generated by the Room EQ Wizard. I couldnt get my RS SPL meter to send correct readings to the Rm EQ Wiz due to lack of the proper sound card. So Im taking readings manually one by one from 20hz to 80hz. I then convert the readings with the correction table, then I input the correct readings manually into the Rm EQ Wiz.


Well, long story short, after messing with it for like 3 hours I think im getting it pretty close. I start over to re-check the readings after I tweaked the bandwidth a bit and began at 20hz. Then I smell the worst possible thing........burning circuitry. I immediately shut everything down to investigate. The smell is coming from my PC-Ultra! Smells just like a fried amp! I know what you're thinking, I had it at full excursion or since it was at 20hz it was too much for it. My Denon reciever's volume level was at -35 for all of my tests. The gain on the SVS was at about 5/8 or just over half way. My target db was 90db's so its not like I was at reference level.


Anyway, the amp was very warm to the touch on the outside so I put a fan on it for a while. I then powered it up and played music for a minute and it sounds fine but it seems like it doesnt have the oomph it used to. Also, it still has the nasty smell coming from the ports while playing.


So, it still works but seems like less power than it used to have. It still smells bad while playing. What do I do??? :( HELP!! :(
 

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Email SVS tech support; you will get a much faster answer than here. Sounds like an overheated VC to me. The epoxy holding the VC to the former stinks when it gets hot.


How long did you run each test tone? How long did you let the woofer rest between test tones?


3 hours of more or less continuous sine waves at 90 dB is probably enough to overheat even the TV12 voice coil. 90 dB is far too loud IMO for sine waves - 80 dB is plenty, and will put far less of a thermal load on the woofer.
 

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Discussion Starter · #4 ·
I ran each test tone about 15-25 seconds give or take. Long enough to get a consistant reading. I think I was trying to be too precise and going slow. Also with literally no rest inbetween tones. There were a few moments in the 3 hours where the tones were off but really no substantial rest was given.


So did I melt the sub or amp. Is there permanent damage? Is there going to be an awful smell forever? Why does it seem less powerful now? I mean, when I crank it to about -3 (just to demo the sub for a few seconds) it doesnt have the "kidney punch" like it once did.


I havent e-mailed svs yet. Maybe its fine and I overreacted. I guess Im hoping that its happened to someone else and if I let it cool off it'll go back to normal. Anyone???
 

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Did you happen to calibrate your sub before going through the test tones?


Maybe your Sub was running to many db's hot.
 

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Discussion Starter · #6 ·
Not sure what you mean by "calibrate the sub". On my reciever's speaker level settings, I have the sub at -4dbs. My other 5 speakers are at like +2, +1, +3, +2, and +2. Those are set so I have an even SPL at center of couch. On the back of the sub I have the gain just over half (or 5/8) and the crossover is set to about 80db cutoff. The subsonic filter is at 20hz since im not using any port blockers. The parametric EQ is taming a huge spike I have at 45hz. What else is there? My reciever doesnt have a High, Med or Low subwoofer setting like some others do.
 

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Call SVS - all anyone here can do is either commesarate with you, or freak you out even more. Good luck.
 

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First of all 90db is too much when calibrating your sub. I would shoot for 75db as mentioned before. Also, you shouldnt need 15-25 seconds for each tone. 5-10 seconds should be more than enough to get a correct readout on your speaker meter.


Not sure what to tell you about your sub. I'd call SVS. Take it easy when running low frequencies at high decibels through your sub.
 

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Discussion Starter · #9 ·
I emailed SVS, waiting for response. Ill post when I get a reply.


I had no idea 90db's at 20hz was too much. Thats what I get for trying to do something on my own with no help. I ask and ask and ask questions. Try to learn as much as I can. Read threads all night long. Slowly build confidence in my ability. Buy all the recommended gear. Then BAM! I screw everything up by just not having the expertise or the proper guidence to do the job correctly. :(
 

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Quote:
Then BAM! I screw everything up by just not having the expertise or the proper guidence to do the job correctly.
It's called the learning curve. Trust me...you aren't the first that has posted such a post. ;) Now you know and all will be ok in the end. Learning the hard way is never easy.


75-80 dB is fine for 3-5 seconds then hit pause until you move on to the next after plotting.
 

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With my plus units I ran my tones at ~85dB for 2-3sec. It really doesn't take that long to get a reading, and the meter is going to swing no matter what you do. Just interpolate the midpoint of the swing. After playing each tone (for 2-3sec) I would pause the CD that I burned the various frequency sine waves to, correct the meter reading, and plot it on my table/graph. This would give ~10sec between each 2-3sec tone.


Sounds like you cooked it... :(
 

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SVS has one of, if not THE best CS in the business. Yoou will up and running 100% by mid-end of week!
 

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Quote:
Also with literally no rest inbetween tones. There were a few moments in the 3 hours where the tones were off but really no substantial rest was given.
That's the problem.


Woofers are not designed to be continuous output devices. Bass is transient in nature - even a huge bassy hit on a DVD only lasts a few seconds at most - something the voice coil can easily tolerate - even at much higher sound pressures than 90 dB.


But continuous sine waves at 90 dB for three hours doesn't give the woofer a chance to cool off, and eventually it gets so hot it literally starts to melt the adhesives and winding insulation, causing partial or complete failure.


You would be far better off investing in a software program to measure the FR in your room at the touch of a button. The whole thing (including hardware) will only cost a few hundred dollars and you will thank yourself everytime you hit the start button and it spits out the FR 1 second later.


Manual plotting of FR with RS meter correction factors is laborious and slow, but it does work. If you stay with this method, run the sines at 75-80 dB for maybe 5 seconds (plenty long to get a reading). Give the woofer at least 20-30 seconds to cool between sines. And plotting at 1/12 octave resolution is plenty for your purposes; don't plot single Hz resolution - it's a waste of time.


You aren't the first person to cook a TV-12 woofer (are your reading this Gordon ;)). Hopefully SVS tech support will get you up and running again soon, but technically this event is considered product abuse - so be extra careful in the future with sines. Under normal operating conditions (music/movies), this is a very rugged subwoofer and you won't have any durability problems, even at loud playback levels.
 

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SO @ what fr do you test so you know what volume to set your receiver @ to be calibrating @75db? Or just use Avia sub test tone and adjust until it is 75db?
 

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TAS,


Probably your sub is still OK, but if you haven't already you will hear from Tech Support soon I am sure. That smell was most likely the adhesive on the Ultra woofers voice coil. The 10 layer aluminum coil it uses is very very (very) durable, but three hours of high SPL sine waves is insanely abusive, to say the least.


Keep in mind (as discussed on this page here: http://www.svsubwoofers.com/faq_rscomp.htm ) that "90dB" with a sine wave is quite a bit more than that in actuality. It's pushing 100dB nearly. If it was a 20hz transient that's one thing but as mentioned above sinces are continuous waveforms and can kill a VC in seconds if you aren't careful (I know, I've done it. Well didn't kill it exactly, "mortally wounded" the woofer in question more like it ;^) That the Ultra lasted 3 hours in your inadvertent torture test is pretty stunning actually.


We're not going to leave you twisting in the wind if the woofer needs to be swapped out, but hopefully you have new-found respect for just how sine waves work.


PS, the burning "varnish" on the Ultra's coil can indeed be pretty smelly. The odor will tend to hang around in the room, and perhaps even permeate the internal batting material for a while, but it will fade fairly soon. Spritz a bit of "Febreeze" or something like that around the sub (don't spray it INTO the sub, but a bit of mist on the fabric and port grill won't hurt anything. Don't ask me how I know these things, I just do 8^0)


Ron Stimpson

SVS
 

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Damn! I'm going to read my manual a few times before I even hook up my new PC Ultra!


My HT wont be finished until October, but my SVS PC Ultra arrived last night!


I had no idea this thing was soooooo BIG! Cool! I cant wait to hook it up... I was going to hook it up to my current home system, but think I'll pass until I can properly hook it up to my new 4806.
 

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Discussion Starter · #19 ·
I was really hoping Ron would chime in, thanks. Still no response from SVS but im sure itll be soon. Everything makes sense now. Having a tartget of 90db is just insane. Running test tones for 20-25 seconds is way too much. Wish I knew all this before. Ill re-post after a response from SVS.
 

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Don't feel bad. I was doing the same thing yesterday. I downloaded some test tones from one of the threads on this board. 10 seconds for every freq from 80Hz on down!! Luckily for me I only went about 10 min. What a f*****g moron I am!! No strange smells or sounds and my Ultra is playing loud and clear!! I count myself as very lucky and now more educated!! I was watching "Rush in Rio" when Neil Pearts drum solo hit something pretty low and I heard a pretty unpleasant clunk!! My SPL meter caught a peak of 110db--OUCH! Yes, I know, but Rush sounds best VERY loud. Yes my sub was calibrated about 3db hot,, now its calibrated flat with the rest of the system. I thought I would play with the PEQ, thats what led me down this road to begin with. I felt so bad I even shot an email to Tom V., he said he understood, HE's a Rush fan too. :D :D
 
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