Hey Doc...

Grimster74

See if you can help me make this guy understand the whole SS filter thing on the SVS's. He's thread is over at the HTF. Here is what he wrote.

Hello guys,

I recently purchased a 20-39pc+ for my HT. I have it hooked up to a Harman Kardon avr55 which is 55watt per channel.

It is in a fairly large area, which I have tried to close in as much as possible.

My problem with it is the volume. If I turn the sub up past 40% volume, with the receiver on 0 boost, once in a while a movie will make it bottom out. Or over exert, whatever you want to call it. It sounds bad.

I try to find a happy medium with the volume, but some movies hit hard and will bottom it out. I hate adjusting it per movie.

The sub just sounds so weak unless I can turn it up past 40% volume.

I do have it in a corner, and I did calibrate it. But who really uses calibrated level on thier sub!


How high do you guys have your SVS turned up?

I see people hitting 115 db on a 20-39pc, I get nervous at 95-100db's of it bottoming out. Why are the drivers so weak?

I had an old JBL 12inch sub before this that I could run at 100% power and never heard a "bottoming" out noise.

I also can crank my mains/center to the receiver max and never hear anything bad. Klipsch quartet mains, academy center.

I am very confused, I feel like I am constantly babying this SVS, it feels fragile.

Thanks

Dr. Spec

"sigh"............he sounds like a plant, or an idiot, or both.

95-100 dB - GAFB.

Let's see how this develops over there.

It is still possible to bottom a sub, even the the SS filter at the proper setting. Sounds like he's overdriving the unit. Claims he calibrates, but then throws that out the window and probably runs much hotter.

The old JBL was better? GAFB again.

Stay tuned.

Grimster74

This dude sounds like a !@#$ing clown. This is what Tom Vodhanel stated:

Hi Brian,

In approximately 7000 cu-ft, a single PC+ isn't going to handle anything close to reference levels on today's action oriented DVDs. We might be able to optimize your subwoofer a little better though.

1) Please read the instruction manual. You should NOT set the amp to 16hz unless you use one port plug to change the tuning point of the enclosure to 16hz.

The purpose of the subsonic filter is to ATTENUATE the signal strength below the tuning point of the enclosure. So when you have all 3 ports open (20hz tuning) you should only use the 20hz setting on the amplifier. When you have all three ports open, and use the 16hz setting on the amp...not only aren't you attenuating the signal...you are actually BOOSTING it. This is very abusive to the subwoofer driver and will often lead to premature failures.

So for now, don't use any port plugs and set the amp to 20hz mode.

2)If you haven't already, try placing the subwoofer in the corner closest to the key seating positions. This should maximize the system *sensitivity* of the subwoofer...giving you more output for a given amount of input power to the driver.

3)be sure to calibrate the whole system with a SPL meter. Set all speakers to the same levels, and once finished, don't adjust anything separately (like the subwoofer volume knob).

Let me know if this helps at all Brian,

Tom V.
SVS

Here is Brians responce:

Ok Tom, I set it to 20hz, and no ports plugged. The sub is in a corner close to the listening position. I have calibrated every speaker.

I understand I won't get reference levels with 1 svs. Not too worried about that at all.

What bothers me is, what is the use of a 525 watt amp, if the sub can't be turned up more then 40% without bottoming out? Seems like the standard 20-39pc with the 325 watt amp would be plenty. Why the extra power, if it bottoms out?

I am afraid of blowing the sub. In some movies like 2 fast 2 furious, you want the extra bass to feel like your there with the thumping cars, etc.. yet I am afraid to turn it up.

Thanks for your advice,

Brian

Grimster74

For those of you following this thread, seems Brian is finally starting to get the idea.