CS2 Bi Amping

The 71 Super

Hello,

This is my first post on Polk Audio but I have been reading threads for almost a year (that is how long I have had Polk products). I have searched the archives but can't seem to find information about bi amping the CS2 - it does not have a bi amp style post.

So here is the situation, I have a BB1265 amplifier that is a class A/B amplifier with 12 channels by 65 watts or 6 channels by 130 watts. I am using this amplifier to power my home theater system. By this I mean my two Monitor 70s and my CS2 center channel. I have removed the binding post jumper plates on my monitor 70's and I am sending a bridged channel to each post. So I have 130 watts to the lower post (sub/mids) of the monitor 70's and 130 watts to the upper post (tweet) of the monitor 70's (I am using an RCA splitter to send two signals to the left tower and two signals to the right tower).

My problem is that the CS2 only has a single set of post, and right now, my Monitor 70's are totally over powering the center channel and things sound odd. Here is the deal, with the monitor 70's bi amped I have heard things I have never heard before. I listen to music and watch movies and I am like "wow, I never heard that before".....I love this and the amount of new sound I have.

So, how can I make the CS2 compete with bi amped monitor 70's? Can I just take the monitor 40 rear post and replace the CS2 with it? Is the wiring and the crossovers the same on a monitor 40 and the CS2?
Here is a rear pic of the monitor 40 (notice the two post):

I have an extra monitor 40 that I can take appart.

All thoughts, suggestions, advice is greatly appreciated.
Thanks,
Harry

P.S. I have monitor 70's series one towers, monitor 40 surrounds, CS2 for a center, and a PSW12 for a subwoofer.

VR3

Bi-amping will not help your issue.

I would recommend a bigger center channel.

The 71 Super

Hi VR3,

Is there a specific center channel you would recommend with my current set up?
Are there any mods like the ones on your website that I can do to help?

VR3

Have you run any type of calibration to your system? It sounds like there may be a configuration issue.

There are mods you can do but I am not sure it would benefit you until we cover more basis in your system such as calibration of levels and so forth.

You have the largest center in the line up you own, using Monitor 40s may be a good idea too..

The 71 Super

Hi VR3,

I have used the microphone that came with my Onkyo TX-SR702 to do an automatic calibration of the system. Based upon that and what I have read from the monitor 70 manual here is how I have things configured:

Speaker Configuration
Subwoofer = Yes
Front = Large (per Polk Audio’s manual page 3)
Center = Small (per Polk Audio’s manual page 3)
Crossover = 80Hz
Double Base = Off

Speaker Distance
Left = 16ft
Right = 16ft
Center = 13ft
Sub = 14ft

Equalizer = Auto

Level Calibration
Left = +1
Right = +1
Center = -1
Sub = +2

If there are any other settings you need to know just ask.
Based upon the above information, what are your comments?
Thanks

txcoastal1

First turn your fronts to small, this will send the bass to your subs LFE below 80hz and probably balance out your front 3 speakers.

Feel free to manually adjust each channel according to your preference.

The 71 Super

Hi txcoastal1,

I will try chaning the setting of the front speakers from large to small.
FYI, according to the Onkyo manual (page 46) it says to set any speakers to large if they are 6 1/2" or larger (the monitor 70's are 6 1/2") and the Polk's owner manual (page 3) says set the monitor 70's to large.

I am realizing that these may be more of guidlines than actual rules to follow.

F1nut

If you have your L/R set to large and your center set to small of course the L/R are going to drown out the center. Not to mention your L/R are set to +1 and the center is set to -1. If anything the center should be set higher than the L/R.

BTW, you are not really bi-amping. True bi-amping is a completely different animal requiring separate amps, each with its own power supply not a shared one and the use of active crossovers.

Edit: They are not very forthcoming with info on your amp requiring one to login for more detailed info. What are they hiding one wonders?

The 71 Super

Hi F1nut,

I was going with the idea that the automatic calibration would be 'smarter'....that is it would know with the increase in wattage to the towers that it should turn up the center channel so it would not be drowned out. I guess it is not as smart as I thought (I did the calibration after hooking up the amp).

I struggled with bi amping versus bi wiring. From what I have read bi amping is having power from different power sources sent to each of the post on the speaker. Since my amp has several power sources I thought that meant I was bi-amping. I didn't realize that to bi-amp there needed to be two or more physical amplifiers.

Here is the text about the amp:

The BB1265 & BB865 multi-channel models have
the discreet power supplies paired monaural so that demands put on one channel
do not affect performance of the others. A massive toroidal transformer assures
adequate power reserves. Discreet output devices allow the amplifier to drive low
impedance loads with very low distortion. Huge filter capacitors improve dynamics
and lower IM distortion, while providing a sustained energy storage for low bass.

Here is a pic of the inside:

The 71 Super

Ok, so I changed the front speakers to small and OMG my sub is amazing. In fact, it is the thing that is overpowering now!
Once I changed the settings, my sub seems to be playing a lot more bass and it plays more often. I was under the impression that with the front speakers set to large it would help with mixing the sub and the fronts, but now I realize the sub was just playing a small role in the overall system.

What is a bit weird to me is that the sub is playing when the receiver is on the stereo setting (I am listening to the radio or a cd). Is this suppose to happen....I thought stereo only meant two speakers?

Is there an order to adjust the sub? Which one of the following should I do first, second, third.....?
- adjust the volume on the back of the sub (currently at 3/4)
- adjust the crossover (currently at 80 Hz)
- adjust the level calibration (currently +1)
- ?

FYI, I am using the LFE method to connect my sub and want to keep it in the same location that it is currently at.

Thanks for the continued support.

amgala

Here is a good article for the small vs. large speaker setting: http://www.audyssey.com/blog/2009/05/small-vs-large

F1nut

The BB1265 & BB865 multi-channel models have
the discreet power supplies paired monaural so that demands put on one channel
do not affect performance of the others.

Hmmm....looks like one power supply to me.

What is a bit weird to me is that the sub is playing when the receiver is on the stereo setting (I am listening to the radio or a cd). Is this suppose to happen....I thought stereo only meant two speakers?

To take the sub out while playing 2 channel music, set the AVR to direct or some such.

teekay0007

71 Super - To listen to 2-channel sound from your fronts only on the Onkyo, you want to set your listening mode to Pure Audio.

What "amazing" sub are you using? Typically, you should set the volume knob on the back of the sub to half volume prior to running the calibration program. Where you have the crossover knob set on the sub doesn't matter if you're using the LFE channel connection from your receiver since the sub's crossover setting will be overridden by the individual crossover settings that are set by the receiver's calibration system. These crossovers can also be adjusted (after you run the calibration) in your setup menus to your liking, if you so desire.

The 71 Super

Hi Amgala,

Thanks for the link. It helped and was an easy to follow article.

The 71 Super

teekay0007 wrote: »

71 Super - To listen to 2-channel sound from your fronts only on the Onkyo, you want to set your listening mode to Pure Audio.

Thanks for the tip....after looking through the Onkyo manual again, I realized the colored squares represent the speakers.

teekay0007 wrote: »

What "amazing" sub are you using?

I have the PSW12. It sounds amazing because it is now actually playing correctly......

monepolk

The 71 Super wrote: »

Hello,
I have an extra monitor 40 that I can take appart.
.

VR3 wrote: »

Have you run any type of calibration to your system? It sounds like there may be a configuration issue.

There are mods you can do but I am not sure it would benefit you until we cover more basis in your system such as calibration of levels and so forth.

You have the largest center in the line up you own, using Monitor 40s may be a good idea too..

Maybe you over looked this?