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Discussion Starter · #1 ·
I am having a problem placing my left & right surrounds speakers.


I have a dedicated home theater with an Infocus 4805 projector. The room is 23' x 15' wide. My closest seats are 14' from the screen.


Using a Denon 2800? amp (7.1 sound)

Polk audio center channel

Kef 104.2 front L&R


I just purchased a pair of Polk Audio surrounds, the LSi series. I don't seem to be getting enough sound out of them when in "Dolby D" or "PL II" mode, which is what I get when watching Comcast HD material.


--I hooked the surrounds to the the "surrounds" output on the amp. I do not have rear speakers installed, and turned them off at amp menu.


--Enough sound means to fill the rear of the room, even with minor sounds. I've had regular B&W stereo speakers hooked up previously, and had very full sound.


Any thoughts?
 

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Is your question related to placement? THose are bipoles, right? Stick them on the walls about 5 feet off the ground and a bit behind your seats.


As to the sound levels, make sure you calibrate the speakers with an SPL meter. They may be less sensitive than your previous speakers. Use an Avia or DVE disk and play the broadband test noise, make sure they are set to uniform levels and are wired correctly.
 

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Discussion Starter · #3 ·
I am having a problem with placement, but I think it's due to, like you say "less sensitive" speakers.


I did calibrate the speakers with Avia. It works great with DTS (using my DVD), but I am getting very little sound with HD and standard cable.


I have the choice of bi/di-pole. I tried both. Di-pole is suppose to give more all-around sound, but I'm not getting much surround at all.


--Is it possible the Polk Audio LSi is not right for my application?


Thanks.
 

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If it's working with DTS but not DD from your cable box, the problem is probably the receiver, the cable box or both. You need a digital connection from the cable box, you need to turn "on" the DD in the cable box, you need to maybe calibrate the speakers in all surround modes (I do, not sure about your receiver)... there is a test channel in HD at 4 am or something, can't remember the specifics, but you may want to get up and check it out.


Alternately, there could be just not much surround info from your cable box, watch a movie in HD and see if you get anything.
 

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Quote:
Originally Posted by hhankk
I am having a problem with placement, but I think it's due to, like you say "less sensitive" speakers.


I did calibrate the speakers with Avia. It works great with DTS (using my DVD), but I am getting very little sound with HD and standard cable.


I have the choice of bi/di-pole. I tried both. Di-pole is suppose to give more all-around sound, but I'm not getting much surround at all.


--Is it possible the Polk Audio LSi is not right for my application?


Thanks.
Hi Hank,


I'm sorry you're having difficulties.


A couple of factors come to mind. First, your speaker are 4 ohm. Your Denon Receiver is likely only rated down to 6 ohms. In browsing through the Denon web site, they list an AVR-2805 receiver that is rated at 100 watts per channel at 8 ohms, and 135 watts per channel at 6 ohms. If the receiver was designed for 4 ohms it would give it's 4 ohm rating.


An other factor might be that you are simply used to the sound of direct radiating speakers that project the sound directly at the listener. Whereas a bipole/dipole design places the listener in a null with the bulk of the sound being directed into the walls. The listener therefore hears mainly a diffuse sound of the reflections.


The fact that your LSi's have a lower efficiency, in of itself, shouldn't have an affect if you've calibrated all your speakers to the same sound pressure level. However, if your receiver already has difficulty with supplying power to a 4 ohm load, it certainly doesn't help to have less efficient speakers which would require more power to drive them to the same levels of other more efficient speakers.


I am at a loss to explain why you are getting a great sound from your DVD versus your Comcast receiver. However, it may be as simple as the broadcasts are not being transmitted in 5.1 sound. I have been disappointed to receive HD broadcast with Dolby Digital 2.0 or Dolby Surround (2.0). Does your receiver have a feature that displays the amount of channels that you are actually receiving?


If you still have access to your old speakers, it may be worth experimenting with them to see if you are are getting surround signals to them when listening to certain Comcast broadcasts.


Good luck.


Larry
 

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May I suggest the FXI5 bipole dipole surrounds. I think Larry nailed it as those are 4 ohm and I think you will get much better response out of the 8 ohm FXI's.
 
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