Need help with center channel speaker

[Austin Powers]

I have a Marantz SR7400 and a pair of older Paradigm that still sound good to me. My next step was going to be a center channel. I bought a Polk CSI5 (on sale for $300 at Circuit City). Adding this speaker seriously downgraded the sound quality of a movie. Dialog which once sounded full coming from my Paradigms now sounded like it was coming from a single small speaker. Some music was also coming from the weak center channel that once sounded full from the Paradigms. I thought I was getting a large enough speaker for the center. Did I perhaps have something configured incorrectly? In the setup, I tried big & small speaker options, and tried all the available theater modes. Funny thing, but when I set the receiver to "auto", it just played in stereo mode w/o the center channel. Makes me wonder if something is wrong with the receiver because of this and also because the Polk CSI5 sounded good in the store.

This was my first experience with the center channel added. Now most of the dialog and about half the other sounds come from the one smaller center speaker. To me it seems logical that this speaker(s) should be as big as your left & right speakers? Otherwise it seems like adding the center would be a downgrade? Has anyone else experienced this? I'm thinking about getting another pair of Paradigms full size speakers to use as a center.

Thanks for any help.

[NickWH]

The reason why it is recommended to use matching speakers across all channels in a surround system is called "timbre matching." This is more important across the front than it is front to rear. You can't just slap a bunch of speakers together and expect the sound to be coherent across the soundstage. The speakers voicing, the electrical sensivity, the cabinet system used, all contribute to how a speaker sounds. If you were to use a matched center, the similar tweeter/mids, with the same impedence and (hopefully) the same sensivity, you will find that the soundstage will be much more seamless. Variations in volume you can easily compensate for on the receiver, but not the other aspects.

IMO, using a pair of speakers for a single channel is overkill, unless you have an 80-inch projector screen in a 30 x 40 foot room, etc.

[Woochifer]

It doesn't matter how good a center speaker sounds by itself. The center speaker's role is to anchor the center image in a multichannel setup and it has to blend in with the other speakers. As already pointed out, the center speaker cannot adequately do that role if its voice characteristics deviate significantly from the main speakers. With a center speaker, it's all about the voice matching. If the tonal characteristics are different enough, then the center speaker will standout as a point source, and that creates the phenomenon that you describe where the imaging now sounds like everything's funneled into the middle with no spacing.

Sounds like those Polks are voiced very differently from the Paradigms. You should try out a Paradigm center speaker and see if it is a better match. If you have an older model, your best odds are to find a used center speaker from the same series as your mains. Paradigm's most recent speaker series updates have audible differences from their older models. Ideally, you would use a third main speaker in the middle. But, if your TV sits where the middle speaker is supposed to go, then the center speaker is a necessary compromise.

The other issue that you have to account for is the setup and positioning. The horizontal alignment of the center speaker means that the match won't be perfect, but correctly setting it up can make the match a lot closer. One factor that's very often overlooked is the delay timing. Ideally, you want the front three speakers equidistant from the listening position, but if you have all three aligned in an even row along the front, the center speaker is actually closer to you than the mains. You should either move the center speaker back, or increase the center speaker delay timing, otherwise the center channel can sound overly abrupt. You should also double check the levels with a SPL meter, and make sure that they match the mains. This type of matching is not something that you should do by ear alone. Also, if the center speaker is positioned significantly higher or lower than the mains, then you should either change the height such that it's closer to the mains, or try angling it towards the listening position.

[stevos2005]

I've had problems with Polk center speakers. Back when I had an all-Polk speaker system, the Polks didn't blend well across the front. I had the fx500i's as the mains and the CS350LS as center. The center sounded tinny and muffled compared to the mains.

I'd recommened for you getting the largest, fullest range Paradigm center speaker that matches your fronts well. Find a place where you can audition it for several weeks. I think that might be your best option.