SVS Bottoming Out?

kberg

Doc et al.,

I re-calibrated my system to the DTS tones on the S&V disk, using 85db as my base calibration volume. With this as my base volume setting, the master volume on my Onkyo reads "82" when I hit 85db on all my speakers (except the sub which reads about 89db) on my Rat Shack meter set for C-weighted, slow. I wanted to have my sub about 4-6 db hotter, so the sub may actually be 6db hotter because of the Rat Shack meter typically displaying 2db lower for the sub than it actually is.

When I put on the "Depth Charged" scene from U-571, I heard a knocking sound which appeared to be coming from the sub, indicating that it was bottoming out. But my question is...

...should I be expecting the sub to be bottoming out when my Onkyo is displaying only "70", which after calibration, is 12 clicks under reference? (the place where it bottomed out is during this scene where you see the shock waves above the water surface, not underneath it)

I swear I have played this scene louder before without hearing any knocking sounds. What gives?

dorokusai

Do you know where you pet is?

fireshoes

Did you calibrate using the raw Radio Shack SPL meter ratings or factor in the corrections?

Tour2ma

Originally posted by dorokusai
Do you know where you pet is?

LOL... You mean his deaf pet?

Good question Fireshoes...

fireshoes

BTW, on your Onkyo you should be able to change the setup options so your volume number is Relative rather than Absolute (i.e -12db from reference instead of 70).

fireshoes

Radio Shack SPL meter corrections

kberg

Originally posted by fireshoes
BTW, on your Onkyo you should be able to change the setup options so your volume number is Relative rather than Absolute (i.e -12db from reference instead of 70).

If this is a possibility on this model, you got me as to how to do it.

fireshoes

I did some checking and it doesn't appear to be on your model. Sorry about that.

Dr. Spec

You can't use the S&V disc for subwoofer calibration, I've recently learned. Only the Avia disc contains verified sub calibration levels, according to Ovation (the maker of both).

Regardless, the DTS tones on the disc may be off a bit (read hotter), as compared to the DD tones.

Compare you DTS calibration with Avia or the AVR test tones and see how much disparity there is.

The sub baseplate could be rattling on a hard surface (unless it's on carpet).

Something near the sub could be rattling (I've seen this mistaken for bottoming more than a few times).

The infrasonic filter setting could be mismatched; check the switch and the port config - 20 Hz and all three ports open is what you want.

Did you recently alter any furniture in the room or make any other similar changes?

kberg

So, from reading the link regarding the corrections on the SPL meter, it seems likely that I could bottom out the sub at a much lower volume based on the low frequencies in the Depth Charged scene in U-571. I just don't remember this happening before which was the main reason I asked about it.

Maybe I should just calibrate the sub without making it any hotter than the rest of the speakers to allow for "exceptional" scenes like this - I don't know.

kberg

Originally posted by Dr. Spec
Something near the sub could be rattling (I've seen this mistaken for bottoming more than a few times).

Doc, I think you hit it with this one.

A while back when I was playing the "Depth Charged" scene much louder with no ill effects, I believe there was NOT a large (5" diameter) candle sitting on a glass plate (of about the same diameter), which THEN sat less than 4 inches from the sub ON A RAISED TILE HEARTH! Yep - it was likely THAT which was causing the rattling! It is so close to the sub that I bet I mistakenly thought the sub was bottoming out. I can't test that theory now because it is too late, but I will sometime tomorrow by moving that stupid candle (oh, and there is a smaller one on the other side of the hearth that has to go, too)

Thanks for the suggestion - I think this solved the problem - funny how some seemingly complex problem can have such a simple solution.

gatemplin

Originally posted by Dr. Spec
You can't use the S&V disc for subwoofer calibration, I've recently learned. Only the Avia disc contains verified sub calibration levels, according to Ovation (the maker of both).

Those ^(*&%in' mother ^%&$#%^s ^(*% $%%^!!!!!

Alright that felt better. I run my sub like 12 -13 dB hot according to SV so that makes sense but it sucks that the tone isn't accurate.

danger boy

i have a 20-39PCi SVS and i love the depth charge scene in U-571 and i've played that several times over and over for my own entertainment and the amazement of family and friends.. i can honestly say.. i've never bottomed out my SVS.

so i'm thinking you may have something loose there buddy.

I mean.. loose in the room.

PolkThug

kberg, those are some insane volume dial settings you're playing with, I don't think I've watched a movie past "66".

VR3

My SVS has never rock-bottomed, period...

My room has felt like/sounded like it was going to cave in on me multiple times (everytime I listen to music or watch a movie), but never any bottoming.........

I watch movies at 10 O'Clock (maybe even 9 O'Clock) on my analog volume control

kberg

Doc and others,

Something is definitely wrong. I removed the two candles on their glass holders sitting on the tile hearth, and I definitely hear a rattling at the base of the sub, even during the relatively low volume and low frequencies of the Depth Charge scene in U-571 at 1:19:04. It sounds kind of like two plastic cups colliding together but at a rapid/repetitive rate.

What could be wrong? Does something need tightening up somewhere? If so, what's the process? Anyone?

Thanks in advance.

KB

PolkThug

Contact SVS.

Dr. Spec

Pull the lid and shine a light down the vent tubes. Is there anything delaminating on the inside?

If not, make sure the baseplate screws are tight.

If it persists, lay the sub on its side and run the passage again with your eyes and ears on the woofer. If it's definitely the woofer, then contact SVS.

kberg

Originally posted by Dr. Spec
Pull the lid and shine a light down the vent tubes. Is there anything delaminating on the inside?

If not, make sure the baseplate screws are tight.

If it persists, lay the sub on its side and run the passage again with your eyes and ears on the woofer. If it's definitely the woofer, then contact SVS.

Doc, forgive me on this one, but what do you mean by delaminating? Do you mean does it appear if anything is being split into layers, or something like that? If so, then no, I see nothing like that after looking down the vent tubes. I'll check the other things you mentioned. Thanks!

kberg

This sucks, Doc. It appears the base plate is fine (tight enough), if you are talking about the three "posts" that the sub rests on - that is what you're talking about, right? If you mean the 7 Phillips head screws holding the subwoofer in place, how do I remove the base to get to those?

I tipped the sub over on its side and played the passage again - same problem. I emailed Tom and Ron and am awaiting a response.

kberg

Another update - Tom V. from SVS has already emailed me (several times) after doing a bit of troubleshooting and it looks like I'll need a new driver, which he indicated he'll be happy to ship, and immediately too.

I've said it before and I'll say it again. These people at SVS know customer service better than any company I have ever dealt with.
Kudos to Tom V. and his team!

HBombToo

Originally posted by kberg
These people at SVS know customer service better than any company I have ever dealt with.
Kudos to Tom V. and his team!

Agreed. I resolved sub clacking with my dual CS+ by turning my h/k preamp way down. as far as I can tell the preamp clips fast for the lows. i use no other amps on board the h/k so its not power available.

twin

Dr. Spec

Sounds like you are in good hands, Kev.

Remove the rubber feet (they peel off with some difficulty). Ask SVS for some new ones or use the optional rubber bumpers. This will expose the large Philips head screws. Remove them and pull the baseplate.

Remove the grill assembly and place the sub on its head on carpeting.

Then remove the woofer screws. Be very careful not to puncture the woofer surround by slipping with the screwdriver. Note the orientation of the woofer (binding posts) BEFORE you remove it. I find it easiest to scribe the basket and the endcap with a magic marker.

You should be able to pry out the woofer at this point and disconnect the leads.

If you can't pry the woofer (they are heavy), with a helper, SLOWLY tilt the sub down with your hands carefully around the woofer. As the sub nears the horizontal, the woofer will suddenly dislodge and you can get your fingers under the lip. DON'T let the woofer fall out or it will rip the amp leads along with it.

When reinstalling the woofer, don't overtighten the screws - a good snug is all they need. And cross torque evenly all around to prevent warping the basket.

Doc

kberg

Thanks for the detailed instructions, Doc. I'll let ya know if I have any questions when it comes time to install it.

So, is the bottom line that the original driver was perhaps faulty and didn't live up to its expectations? How can you tell the difference between this situation versus a blown driver due to "user error"? I honestly don't believe the latter is the reason in my case, but I also want to make sure this never happens again!

Dr. Spec

Who knows? It sounds like the original woof was fine, and just up & bought the farm. Unless someone cranked it to extremes in your absence.......

Unless you were bottoming the woofer with regularity, I would chalk it up to a failed component and carry on as before with the new woof.

All ports open, switch to 20 Hz, and blast off. TC Sounds has been making steady improvements to that woofer and you might even notice a performance improvement.

Doc

kberg

Originally posted by Dr. Spec
It sounds like the original woof was fine, and just up & bought the farm. Unless someone cranked it to extremes in your absence.......

This has to be the case - when anybody else in the family uses my system (a rare event), I'm either around or my wife makes sure the sound is always at a normal listening level.

Unless you were bottoming the woofer with regularity, I would chalk it up to a failed component and carry on as before with the new woof.

This is also what I believe to be the case.

TC Sounds has been making steady improvements to that woofer and you might even notice a performance improvement.

NowTHIS would be a nice side benefit with the replacement.

kberg

Well, I received the new driver from SVS yesterday and installed it last night, using the directions provided as well as Doc's tips. Needed some assistance from the wife in holding up the lip of the driver while I re-connected the leads. Recalibrated today and all is well. As expected, the bass is awesome and there were no problems when playing the passage of U-571, as originally noted above. Still making some "subjective" test runs to determine if there appears to be an improvement on the original driver.

Any other subwoofer manufacturer could have easily given me grief and hassle over this issue. Thanks to all on this forum and especially SVS for taking the worry out of solving a problem in the fastest manner possible and at no expense to me. Doing business with SVS isn't just a transaction, it's an experience.

Dr. Spec

Good news, Kev. I was hoping you would post some feedback on the driver install and the CS experience. Seems all went very well, and you are back to great bass. (thumbs up)

Sometimes UPS handles the sub rough and the VC gets misaligned in the gap and this leads to eventual failure. This is just speculation on my part. SVS might want the original driver back for analysis; they'll pay to return it - just ask Tom if R/D wants it.

kberg

Originally posted by Dr. Spec
SVS might want the original driver back for analysis; they'll pay to return it - just ask Tom if R/D wants it.

Done. I just emailed Tom V. to let me know if he wanted the original driver back for that purpose.