Right now my mains are Polk Audio RTA 11t's. I really would like to have a center to match it (Right now I have a AR PSC25 that does not even closely match) The problem is that the matching polk speaker costs why more then I can afford. I would like to know if anyone has had any luck with building a center to match ready made speakers my mains---esp since I don't have the specs for the polks.....any hope?
I did some poking around on Polk's site and although I didn't find any info on your speakers I think Polk's recommendation that the CS400i matches your speakers is a stretch, being more commercial than technical.
The idea behind matching the center to the sides is primarily to get a frequency response match and I doubt that the CS400 is going to be a response duplicate of your RT11's.
Without a response curve of your speakers you will pretty much in the dark. If you assume that your speakers are flat within a couple of db from, say, 300Hz to 15Khz then any center channel speaker that also exhibits the same flatness will do the job.
BUT, the design of many center channel speakers, including the CS400, is somewhat ill conceived in the first place because of the horizonal layout. The response is going to be different for different listening positions so even if you were to optimize for a single on axis listening position, the situation for the remainder of the audience would be less than ideal.
I don't know exactly what is directed to the center channel in a HT setup but I suspect that one of the full range drivers from Fostex or ? might do the job if they are shielded. Perhaps a single 3" Tangband? The question here is power handling at low frequencies.
May one of the HT experts might jump in here and offer some further insight.
Anyway, I wouldn't be overly concerned about an EXACT response match. The center channel for my regualar 2 channel stereo video watching experience is the speaker built into the TV and it's shortcomings has not caused me any concerns.
Personally, I think HT is a rip off - but that's another thread.
The idea behind matching the center to the sides is primarily to get a frequency response match and I doubt that the CS400 is going to be a response duplicate of your RT11's.
Without a response curve of your speakers you will pretty much in the dark. If you assume that your speakers are flat within a couple of db from, say, 300Hz to 15Khz then any center channel speaker that also exhibits the same flatness will do the job.
BUT, the design of many center channel speakers, including the CS400, is somewhat ill conceived in the first place because of the horizonal layout. The response is going to be different for different listening positions so even if you were to optimize for a single on axis listening position, the situation for the remainder of the audience would be less than ideal.
I don't know exactly what is directed to the center channel in a HT setup but I suspect that one of the full range drivers from Fostex or ? might do the job if they are shielded. Perhaps a single 3" Tangband? The question here is power handling at low frequencies.
May one of the HT experts might jump in here and offer some further insight.
Anyway, I wouldn't be overly concerned about an EXACT response match. The center channel for my regualar 2 channel stereo video watching experience is the speaker built into the TV and it's shortcomings has not caused me any concerns.
Personally, I think HT is a rip off - but that's another thread.
How much closer a match would I get if I were to mount the same model tweater that is in polks into my AR center?
There is no way to tell without measurement of the response. It is possible, but very unlikely, that your proposed solution will work.
If you were to build a center channel box with the same drivers as used in your RTs and duplicate the crossover you might get a decent match. New problems arising would be the box size/low frequency tuning and the fact that the drivers might not be shielded.
Even though you have discovered that the AR doesn't sound like the Polks and that you have heard on the grapevine that a match is preferable, are you having real issues with the performance of the system?
What I mean is, forgetting about what you have come to believe ought to be, what is it about your HT audio presentation that motivates you to change the center channel speaker?
The fact is that the effects an unmatched center channel speaker are going to be somewhere between subtle and inaudible.
If you were to build a center channel box with the same drivers as used in your RTs and duplicate the crossover you might get a decent match. New problems arising would be the box size/low frequency tuning and the fact that the drivers might not be shielded.
Even though you have discovered that the AR doesn't sound like the Polks and that you have heard on the grapevine that a match is preferable, are you having real issues with the performance of the system?
What I mean is, forgetting about what you have come to believe ought to be, what is it about your HT audio presentation that motivates you to change the center channel speaker?
The fact is that the effects an unmatched center channel speaker are going to be somewhere between subtle and inaudible.
I would not say that there is anything about my systems that is making me want to change the center, it is just that I am in the middle of tweaking my HT and I am somewhat of a perfectionist. If anyone has a paid audiogon account, i believe there is a review of the RTA-11t on there, if you could maybe send me a copy--it should have the specs on it.
I don't have an account with Audiogon and in fact I never heard of them. I went there anyway but couldn't find a review of your speakers although they were mentioned as associated equipment to review other speakers.
If you continue wanting a exact match I can see no alternative but to either duplicate an RT11 or find a used one somewhere.
This will force you to place the TV above the center channel speaker which, I'm guessing, is about 40" high. You will need to keep the center channel tweeter at the same height and the L and R tweeters.
If you continue wanting a exact match I can see no alternative but to either duplicate an RT11 or find a used one somewhere.
This will force you to place the TV above the center channel speaker which, I'm guessing, is about 40" high. You will need to keep the center channel tweeter at the same height and the L and R tweeters.
The output of the centre channel depends on the source
Let me qualify...
In most cases, the centre channel gets 20Hz~7KHz. This is to satisfy the vocal needs of dialogue while removing the high frequencies which are used to "fool" the brain directionally.
1) If you use an Prologic receiver that gets 2.0 channels from your VCR or DVD, then it sums the 2 channels, and low-passes at 7KHz before amplification.
2) If you have a digital receiver that gets digital from your DVD, it will decode DTS and/or AC3 and go straight to the centre channel amp. Some units will add 7KHz low-pass to ensure than no stray directional frequencies get past.
3) If you have a digital processor that gets digital from your DVD, it is the same as above.
4) SACD multi-channel is decoded at the player and is sent as 6 channel analog to a 6-channel pre-amp and 6 amplifiers.
DVD-Audio is the same as the #2 and #3. SACD is funny in that it requires 20-20KHz from all 5 speakers, so if you have that, you need the facility to turn off the low-pass on your processor/pre-amp. I've heard (anecdotally) that some new DVD-As are also 5.1 full-range, but have no confirmation. I wouldn't be surprised if this is true in the near future.
Mike: If you are at all thinking about upgrading your source, you would do well to have as good at the centre as at the mains.
Bill: You are right about the HT rip-off. The advantages are there, just not available to the pro-sumer. Only audiophile pocketbooks need apply! Get a tour of a 5.1 mastering facility (many audio engineering schools have decent setups) and you'll see how surround is supposed to be implemented. If it doesn't sound as good or better than a THX theatre, you haven't done it quite right.
Let me qualify...
In most cases, the centre channel gets 20Hz~7KHz. This is to satisfy the vocal needs of dialogue while removing the high frequencies which are used to "fool" the brain directionally.
1) If you use an Prologic receiver that gets 2.0 channels from your VCR or DVD, then it sums the 2 channels, and low-passes at 7KHz before amplification.
2) If you have a digital receiver that gets digital from your DVD, it will decode DTS and/or AC3 and go straight to the centre channel amp. Some units will add 7KHz low-pass to ensure than no stray directional frequencies get past.
3) If you have a digital processor that gets digital from your DVD, it is the same as above.
4) SACD multi-channel is decoded at the player and is sent as 6 channel analog to a 6-channel pre-amp and 6 amplifiers.
DVD-Audio is the same as the #2 and #3. SACD is funny in that it requires 20-20KHz from all 5 speakers, so if you have that, you need the facility to turn off the low-pass on your processor/pre-amp. I've heard (anecdotally) that some new DVD-As are also 5.1 full-range, but have no confirmation. I wouldn't be surprised if this is true in the near future.
Mike: If you are at all thinking about upgrading your source, you would do well to have as good at the centre as at the mains.
Bill: You are right about the HT rip-off. The advantages are there, just not available to the pro-sumer. Only audiophile pocketbooks need apply! Get a tour of a 5.1 mastering facility (many audio engineering schools have decent setups) and you'll see how surround is supposed to be implemented. If it doesn't sound as good or better than a THX theatre, you haven't done it quite right.
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