JBL PB12 Issues, Can Anyone (esp. owners) Help? (1 Viewer)

[Chuck C]

Welp, my buddy just got his PB12. We set it up and compared it to my Velo 810x... the JBL extends down deeper in movies with very low bass (J.P. Ch. 11), but you can barely hear and feel it on all other levels (i.e rap, rock, classical, movies with deep bass), even when turned up past 3/4! My sub sounds very robust and clean, and the PB12, despite pushing massive air, just seems missing in action.
Is this a placement issue? Does this thing need to be broken in? Should we screw with the switches and knobs? Do I just have a better sub?
thanks everyone
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Chuck
http://www.hometheaterinsider.com

 

[Chuck C]

good hypotheses, boys....
I had the phase knob at 150Hz most of the time and toggled it between 90 and 150 during the T-rex scene...no difference. I had it switched to LFE the whole time.
We have the sub in the corner placed with the left bookshelf speaker on top, two feet from the TV. We put it in the same place my Velo was in. Switching the phase seemed to have an effect. All speakers set to small connected to a 575x, BTW.
I have a feeling it's definitely an issue with placement. Standing on the sub side of the room...wow!! But on the other side, virtually nothing. I mean, you could feel a huge amount of air comin outta the port, so it's definitely not defective. Could it also be that the four corner pegs are too long or ineffective in some way?
Thanks fellas...
Note: my sub--8" frontfiring, 10" downfiring passive woof, 200 watts peak.
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Chuck
http://www.hometheaterinsider.com
[Edited last by Chuck C on October 09, 2001 at 08:35 PM]

 

[Chuck C]

Chuck, If you have the LFE switched to "on" the crossover adjustment is disabled so that is why you heard no difference between 90 and 150.

Ya, I figured that, but I needed to give it a try. I also screwed around with the x-over knob for music as well--no diff.
We're in a dorm sized 11x13, I'll try the center placement tomorrow.
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Chuck
http://www.hometheaterinsider.com

 

[DonnyD]

Also make sure of settings in your setup menu... some receivers auto switch or default to other settings once an input is changed.
I have just hooked up a PB12 for a friend and it just pounded on movies and music. It is one excellent sub for the money and I am sure you'll locate the source of the problem.
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"I am part of all that I have met, yet all experience is an arch wherethru gleams that untraveled world whose margin fades forever and forever...."

 

[Ron Reda]

Chuck C,
Listen to Sean...he knows what he's talking about! I had my PB12 set up incorrectly and now, after Sean's suggestions, it sounds like a champ!
Regards,
Ron

 

[Chuck C]

Let's break it down....
Here's what I figured last night, tell me if I'm wrong...
1. Receiver set to SMALL SUB=YES
PB12 LFE ON
-----------
Gets All signals below 80Hz Regardless of xover setting
2. Receiver set to SMALL SUB=YES
PB12 LFE OFF
-----------
Gets All signals below 80Hz Regardless of xover setting
3. Receiver set to LARGE SUB=YES
PB12 LFE ON
-----------
Gets All Singals 20Hz-20KHz Regardless of the xover setting, bad for the sub
4. Receiver set to LARGE SUB=YES
PB12 LFE OFF
-----------
Gets all Signals 20Hz-20Khz and depending on the xover will cut off the signal (eg, xover=150Hz, sub gets all signals

 

[Chuck C]

whoa baby...turned up the sub level from the receiver (o to +6 dB)...wowsa
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Chuck
http://www.hometheaterinsider.com

 

[Vin]

Here's what I figured last night, tell me if I'm wrong...

1. Receiver set to SMALL SUB=YES
PB12 LFE ON
-----------
"Gets All signals below 80Hz Regardless of xover setting"

Correct.
2. Receiver set to SMALL SUB=YES
PB12 LFE OFF
-----------
"Gets All signals below 80Hz Regardless of xover setting"

The sub's cut-off will be active when the LFE is set to off so where it's set will make a difference, i.e., if you set it anywhere below 120Hz you'll lose that part of the LFE...not recommended to do it this way.
3. Receiver set to LARGE SUB=YES
PB12 LFE ON
-----------
"Gets All Singals 20Hz-20KHz Regardless of the xover setting, bad for the sub"

When using the sub-out from the receiver, the sub will always receive the entire LFE which can include info up to 120Hz. In addition, it will receive deep bass below the receiver's crossover (usually 80Hz) when speakers are set to SMALL. Any speakers set to LARGE will receive the entire frequency range as encoded for those channels. In other words, nothing is crossed over to the sub from those channels that are set to LARGE but the sub still receives the entire LFE.
4. Receiver set to LARGE SUB=YES
PB12 LFE OFF
-----------
"Gets all Signals 20Hz-20Khz and depending on the xover will cut off the signal (eg, xover=150Hz, sub gets all signals

 

[Chuck C]

awesome Vin, thanks!
and God Bless America baby!

 

[Robin Wingo]

I had a PB-12 but I returned the sub back to crutchfield, the sub was really hit and miss for me. It sounded well for movies but everything else I was not happy there was also a funny smell in the port area maybe I had a bad one, so I gave up and purchased a B&W ASW1000 to match my 303s and it sounds 10x better in my opinion but it cost 2x more money.