Center channel

that is what i did with my boston acoustics setup..different series and different tweeters...i dunno..i am not sensitive enough to say the timbres are not matched ....to me they sound great...if you cant tell who gives a rat's ass,huh?
that said i would get the largest and best quality center you can afford..it really is the workhorse for home theater...the rest are just sideshows except for the subwoofer...equally important...

How many people are listening? For just yourself or maybe 2 people, my opinion is to focus on your mains - you only need a center channel for large groups sitting in a wide dispersed pattern. Otherwise, the center image on good speakers should be razor sharp.

he already has his mains....his polk bookshelf...his question was about the center...

My point is that if there aren't a lot of listeners, he shouldn't need to waste money on a center.

well i guess that depends on the setup he wants...true with a good pair of mains he can get a soundstage but if he is looking to get the 6.1 experience then he will need a center...but good point taken....you need to factor in the situation and then decide if it is worth the outlay...
i think though with polk bookshelves(good but not great) and nice center would complement but that imho. or actually i take that back...i think the polk are adequate and a sub would give you most bang for the buck right now..

Which Polk Audio bookshelf do you have?

Get a high quality center and you won't be sorry. Feed it from a clean power amp and you will be amazed. Your room is quite large so a center with 2 6.5 in mids would be needed.
I started on a cheap center that I thought was good due to it's weight, it was a design acoustic model and it sucked. I then bought a NHT vs2a that was much more than what I planned on spending but I'm glad I got it.

other than deep bass which can and should be handled by the LF channel and mains,the center channel should be close to an exact match in timbre to the front left and right speakers if accuracy of the image is important to you .
You can and most do cut corners here but if you know how the surround signal operates then you would realise the front center is the most important speaker and is at approx. +6dB higher than the left and right speakers.
The reason is to "lock" dialog and screen centered effects and only the off camera or left to right (or right to left) motion effects are handled by the main stereo pair.

the only plave you can really cheat is the surround channels (side and rear) if you want the best end sound and directional effects.

what i would do if i wanted to save some loot is attempt to obtain a set of drivers identical to the main speaker drivers (hint-polk service dept) and then make a cabinet to house them.

just an suggestion man but the center is way more important than most realise and any corners cut here are easily heard when compared to a properly set up surround system.

sounds like an ideal solution and you could even use both stacked and wired in series (16 ohm) or parallel (4 ohm,dangerous load for some amps) or maybe even use the extra speaker as a rear center fill for a more seemless back to front progression.just watch the levels of the rear/side channels.
They should never draw attention,be heard at all actually,unless there is a defintitive direction cue from that direction.

I remeber the first time I properly set up a surround system the way it is supposed to sound (then went on for a while installing them for loot ) and i was watching a movie,can't remeber the title,and i am sitting there when all of a sudden this freakin 747 comes OVER MY DAMN HEAD !

Man !

I almost crapped myself ! And then after the initial shock wore off the smile would NOT go away off for the duration of the evening !
i was way too proud of myself to care what an idiot i looked like

couple of things i picked up

1-put your subwoofer in the spot you will be sitting at then walk around the room and listen for the tightest,least boomy and deep bass.Once this position is found by you standing there mark it and put the sub in that position.Don't worry about sub phasind a time delays and all the other jargon in the manual.It is about the sound and not the specs.Boomy bass in the listening position will give you a headache and get the position wrong up front and the fix will be an expensive equalizer and/or room treatment which may not integrate.

2-set the sub low pass for around 50-60hz if used with full range loudspeakers but at or above the main speaker F3 if used with satellites.since small speakers are nornally stand mounted the floor will not augment the bass and it will usually roll off gradually so a high sub crossover will blend but if TOO high will become sloppy and incoherent from blending with too much of the satellite bass frequencies-experiment for best sound according to the system .Set the phase of the sub (+or-) phase switch for the best (read most amount) of bass produced then set the level using the voice of a male announcer on the FM radio dial.Back off the volume until there is no voice change as the sub is switched on and off.Again there will be some leeway for fine tuning but this is a good baseline starting point.

3-check the entire room for anything that buzzes or rattles even if it is just minor.You will not be able to identify WHY but the sound will get on your nerves eventually and tracking it down will be a pain later.Just tell the spouse/parents/insert here you are tired of the decor and it is time for a change.I am telling you-far too many who blame their susyems for being harsh ,that have irritating highs,are really hearing room buzzes from family pictures,displays,flower pots,wall mirrors,candy dishes.....
If you MUST have these things to please the family then damp them down.That is,place something between the two hard surfaces (wall/mirror.table/glass dish.etc).Teflex is great but even cork will do in a pinch.anything as long as it breaks up the "hard surface to hard surface" contact.

4-set the main left and right speakers for best stereo sound at the listening position.leave all the other speakers ,including the sub OFF for this.This is usually with the tweeters at or near ear level when seated and slightly toed in towrds the center but depending on the system dispertion characteristics can be anything from 0 degree toe in to 45 degrees and with the stereo image crossed in front of the listening position.

5-do all in your power to get the center channel on the same height/depth plane as the main L and R channel speakers.This is usually not possible and means the center dialog channel will be above or below the stereo pair but the front to back must be dead on or you will blow the illusion of realism.Very important.

6-rear channel setup : I hate using just two speakers for the surround channel and am in the habit of putting three down each side plus one distant speaker directly behind the listening position but this is not practical for mosyt installations so if two only then :
Do not aim the speaker directly at the listening position if at all possible !
It is better to aim them directly at the wall (ugly) or into a corner (also ugly).At the minimum aim them cross-room and not "into the room.And DO get them up off the floor and speaker stand entirely .Instead use a wall bracket to get them up near the ceiling.Adjust the volume until you can hear the surround channels as a 'distinct' sound then back off the volume until it just dissapears.
Remeber,you are not wanting to even hear these speakers until the locational cue is present but instead want the entire sound field to be seemless and diffused with no apparent holes in the image.
At the same time you don't want any speaker to draw attention until called on to do so and only when set up with care is this possible.

That is how i would do it whgen i almost lost my shirt installing surround systems (not enough work to go around ) and i never looked at the instructions that came with the systems.too damn confusing

Yeah,got a bit carried away again..........typical !

I really feel that with good speakers and one listener, a center channel is absolutely unnecessary. However, since you don't feel that way about your polks, I will assume that the polks don't sound up to the task, so I will now butt out of this thread If your speakers were up to the task, you would have had doubts when you read my opinion