Calling on the Doc...

Grimster74

During a demo today of Finding Nemo, a strange noise was heard from the subwoofer. I own the SVS PB2+, and until today it has performed flawlessly.

The noise occurs at <100db, and at two notches above "Min" volume level on the SVS, which is typically the reference point for me and the volume on the AVR was set at -5.0. It sounds like a metallic ringing, like a basket vibrating very loudly. I know it may not be the best description, but it was not present earlier, and as loud as it is, it would have been noticeable.

What should I do? This has really upset me, and do not know a course of action. Is this what would be considered "bottoming" the sub. I wouldn't now to this being the first time I've heard this.

gacole2000

Obvious question: Are you sure it was not something other than the sub vibrating? I isolated a noise from a window near my sub that had a strange noise. Just a thought.

Good luck- Greg

gatemplin

From my experiences bottoming out sounds like "clack clack clack". It is the voice coil former hitting the back plate. It is loud and metallic sounding. This could be what you are hearing. A little below the tuning frequency of the sub the drivers can unload and easily bottom out if driven hard at those frequencies. It is usually ok but sometimes the former is damaged.
I believe your sub has a adjustable subsonic filter so maybe it is something else if the filter was set properly.

HBombToo

Originally posted by gatemplin
From my experiences bottoming out sounds like "clack clack clack".

me too have experienced this. I think in my case its not an SVS issue but more a problem with my h/k. I got the set points but some stuff is just real unruly.

1/4Twin

gatemplin

Originally posted by HBombToo
I got the set points but some stuff is just real unruly.

1/4Twin [/B]

Huh? I have no idea what that means.

You've been hittin the sauce haven't you Hbomb;)
Seriously though, you're right, it isn't an SVS issue. Every sub will bottom out if given enough power.

VR3

I know what you're are talking about.

My Dad's PC Ultra has made the *metallic scraping* noise. It happens with movies when he the bone head plays it to loud and the frequency is hit to low!

HBombToo

Originally posted by gatemplin

You've been hittin the sauce haven't you Hbomb;)

Well I had a Beer but thats it. I don't dare because the wife is due with Tino any minute:eek:

HBomb (not the twin)

gatemplin

Congrats Henry, you didn't name him after Russ did you?

Dr. Spec

Rob:

I just spotted your thread over at HTF. It looks like Tom V is helping you via email. That is the best way to go. The PB2+ is damn near bulletproof if the user does not mismatch the port setting and the tune point. If you kept it at 3/25, I seriously doubt you hurt it.

I agree, it could be something near by making a noise. Have you changed anything in the room or brought in anything around the same time the noise started?

If anything has gotten loose or damaged, SVS will be all over it 100%, I'm sure. Good luck with Tom and send me a PM or an email if you want to follow-up.

Regards,

Ed

Dr. Spec

My Dad's PC Ultra has made the *metallic scraping* noise. It happens with movies when he the bone head plays it to loud and the frequency is hit to low!

I warned you about this before you took delivery. Even the TV12 driver has limits and if you exceed them you will ruin a $600 driver. The TV-12 in particular will give no clear indication it is reaching its limits; it is a very clean sounding driver.

I advise him to either buy another PC-U, or "upgrade" (SPL wise) to a PB2+ for the same price, or simply turn the volume down.

HBombToo

Originally posted by Dr. Spec


If anything has gotten loose or damaged, SVS will be all over it 100%, I'm sure.

Ed

I guess my big problem is a broken foundation:D

HBomb

dorokusai

There is a better word for us Rob...."Clank".

It was very pronounced, and it was a few clanks, but it certainly seemed to have two common things:

Volume on the Subwoofer
Media

The media was the aformementioned, Aquarium scene in FN. The volume varied between half, and two notches above "Min".

My first question is, is that scene THAT low in hz?

What volume levels do you SVS owners set for reference, typically that is?

Would no ports being plugged HAVE an effect or have NO effect on performance at that tune?

Would it just be the fact that that particular scene is just hardcore?

When the sub was backed down, that is, one notch above "Min" then two...everything went back to normal. Later musical tests, and another movie, same previous volume, had no problems.

Thoughts? Oh ok, cool, Tom V is on the job also...good to hear.

Either way, that being just a fluke IMO, that SVS is rock solid. I have not heard impact like that before. Room pressure definetly got higher, it was really cool. With my head stuck near the port, during the Aquarium scene, I thought I lost consciousness for a second. My ear drums were vibrating so much, that it caused vertigo. I liked it.

faster100

Sorry to hear about your Pb2 problems,, i have the Pb2-isd and just played that very scene from FN yesterday for my friend, he was so impressed it wasn't funny.. I know it was well over 100 db with no problems.. It may be a faulty driver?? I dunno... unless you have a large room and the volume was very loud, (100 db isnt very very loud IMO ) Good luck though

dorokusai

No faulty driver, he found the problem. I will let Rob inform the masses if he wishes.

Dr. Spec

The relative gain setting on the sub is really meaningless.

The overall calibration setting, which is a combination of the Master Volume, the sub level in the AVR, and the gain setting, is the real key.

You can only really determine this through Avia or S&V, etc. Have you calibrated the sub, Rob? If so, what were you getting?

If you heard a clank, you probably bottomed the woofs. Darla is a sub buster for sure (see the SVS website under News - but about 27-30 Hz IIRC), but regardless it's hard to bottom the sub in the 3/25 tune.

Rob - what were the port and tune switch settings when it bottomed out? If you were running a mismatch like 3/20 or 3/16, all bets are off on bottoming the woofs; it can happen pretty easily in a large room.

Grimster74

Okay, after doing some serious inspection, I found the problem. On the SVS where the flared port ends, (going into the box that is) SVS appoxied(sp) the port to the flared portion, there was a very thin layer of what seemed to be appoxy which worked its way loose, removed it and ran the test again, as the Doc would say, BULLETPROOF, perfromed flawlessly. Thats for everyons help.

Grimster74

Talk about stellar customer service. Tom at SVS e-mailed me this morning to thank me for taking the time to look into the ports with a flashlight after Doro left. Said that I saved him the time and money of sending me a new driver(s), what ever the case may have been. But let alone from thanking me, he is also sending me a SVS t-shirt and a SVS coffee mug. Know there is no reason for Tom to do this, it wasn't his fault or anyone else at SVS for that matter, but what a kick **** customer service. If all other manufactures had near the CS that SVS has, the world of electronics would be a better place. Thanks SVS, #1 in my book.:cool:

faster100

Originally posted by Grimster74
Talk about stellar customer service. .:cool:

I have found that POLK and SVS have thee Best CS around hands down, Ken at Polk has helped me several times with questions and Ive spoke with Eric at SVS and others, they answer the phone like they are just waiting for your call... Unbelievable!!

Dr. Spec

Glad you found the problem. I can't imagine epoxy causing a "clanking" sound, but I wasn't there to hear it.

In the event the epoxy was coincidental and unrelated, and you really did bottom the drivers, I still suggest you double check your calibration level and also verify you are not running a mismatched tune. In that size room 3/25 is the WTG.

Grimster74

Yeah, after listening to it again last night, thats when I decided it wasn't really a rattling noise. It sounding as if you were driving down the road at 65 m.p.h. and then hang a plastic bag out the window. Thats when I disconnected everything and pulled it out into the middle of the floor to see what was going on, and low and behold, there it was. Hooked it back up and fired up that same scene again, the damn SVS laughed at me.:D Believe me, it is properly calibrated with the DVE disk along with the room eq feature of the 3805 and set to the normal responce which is what Denon recommends for HT purposes. This damn sub is just like you said in the 3/25 mode, BULLETPROOF.

Dr. Spec

Now the "whipping plastic bag" sound I can agree with. An epoxy delamination will probably sound exactly like that.

DVE IMO has a major problem with the sub calibration tone. I strongly recommend you compare it to Avia or S&V or even the AVR test tones.

Using DVE for the sub tone results in your sub being undercalibrated by about 10-13 dB (at least with my copy of the DVD). Most people who use DVE for sub calibration are completely underwhelmed by the resultant non-existent bass response.

I have a large thread on that topic over at HTF - check it out.

Doc