CSi20 vs CSi30 (crossovers, timbre,...)

[GreenTop]

Ê ÊIn an audioholics.com FAQ, Gene DellaSala says,

2 1/2 way systems have recently entered the hi-fi market of loudspeaker design. This design employs 2 bass/mid-bass drivers usually identical in design and size and a tweeter. Usually the bottom woofer is crossed over to produce bass frequencies below 200Hz and the top woofer is crossed over to produce midrange frequencies between 200Hz - 4KHz. The interesting thing about this design is that although the two woofers are crossed over at different frequencies, they acoustically couple to synergistically enhance overall system bass response.
Ê ÊI'm debating between two Polk center channels: CSi20 and CSi30. According to specs from Circuit City, the CSi20 has one driver (5.25" Dynamic Balance) and a .75" Dome Tweeter, while the CSi30 has two 5" drivers (5.25" Dynamic Balance) and a 1.00" tweeter (Dynamic Balance Dome).
Ê ÊI had assumed that both drivers of the CSi30 would be doing the same thing, except twice as much (a silly newbie mistake, I guess), but Gene's "2.5" explanation makes more sense. Is the 2.5, with each midrange handling a different part of the spectrum, the way Polk uses the i30's dual drivers?

Ê ÊMy practical question is: What are the differences in sound (due to the second midrange, the 1 inch tweeter,...) between the i20 and i30? What would be the advantages of the i30?
Ê Êmy audio context: I just bought an Onkyo TX-SR501 receiver with 6.1, will use four 3-way 8-inch speakers (my pair of old Sony SS-MB215, and two new ones, Sony SS-MB350H, which I think are extremely similar) for the front and rear L-and-R, and am not sure what I'll use for the rear-center. Currently I'm in a small room, but eventually they'll probably be in a larger room. I listen to music much more often than movies.
Ê Ê If there is a timbre difference between i20 and i30, which would match the Sony surround-speakers better? { This is something I can't check in a sound test at the store. }
Ê ÊAccording to CircuitCity, the sensitivities are 90 dB for the Sonys, 89 for CSi20, 90 for CSi30. But the receiver has adjustments so I assume this difference could be adjusted for the i20, yes?

Thanks, in advance, for any help you're able to provide.

gt

[GreenTop]

Originally this was a "oops" message, but I discovered that I could fix the original. But I still can't delete this message, so I'll add some information:

Usually I don't listen to loud music (soft to medium-loud) so the ability to play really loud isn't a priority. But, of course, it might be nice to have this option, just in case. Ê :<)

gt

P.S. Thanks for the reply, dorokusai.

[dorokusai]

Welcome to the forum :)

There isn't a timbre problem/issue between the CSi30/40...they use the same drivers, just in different formats. The CSi20 uses different drivers, than the 30/40, albeit the tonal qualities are not extremely far apart.

As to whether they will match your existing speakers is not something probably anyone here can say for sure. I have no experience with the Sony speakers line.

I have heard the entire center channel lineup for Polk Audio. I chose the CSi30, because of the demands that are put on the center in a surround format. I am actually going to upgrade to the CSi40, and move the CSi30 into rear surround duty. The CSi30 handles all my movies just fine, but I want more "hair" on my center, thus the upgrade. In a surround format(5-7.1) your center is going to be handling most if the duty, 50%+, so I would suggest a healthy center channel. Sensitivity isn't that great of an issue for this problem, beings the difference is audibly negligible.

The CSi20 is not the best choice, IMO. Since this is the case, my guess is that you won't have too much of a problem matching the, CSi30/40 with your current speakers.

More folks will post here with their thoughts, let us know what you do. Good luck.

[GreenTop]

Thanks for the information and opinions.

More folks will post here with their thoughts, let us know what you do. [/B] Yes, I was hoping that people could provide feedback on the relative audio qualities of the i20 and i30. I'd like to hear about what you've heard.
The difference in design principles is also interesting. Is each of the i30's two drivers specialized for either lower frequencies or midrange, as described in the FAQ? And I'm suspicious of the i20's single-driver design because, on the Circuit City and Best Buy websites, every other center channel speaker uses two drivers, in addition to the tweeter. Is there something special about using two drivers that gives it superior performance, that puts an inherent limit on the quality of a single-driver system? Is this a design flaw of the i20, and has Polk overcome the limitations so it has good performance anyway?

Any practical help you can provide will be appreciated. (I'll be making a purchase in a couple of days, on Friday.) And the relative merits of the two design strategies (one vs two) is also interesting, just in terms of audio theory.

gt

[VR3]

CSi30, HANDS DOWN! Lots of action goes on in that center channel, the reassurance of just 2 woofers is one reason to buy it! the CSi20 is a bookshelf with an exstended cabinet. The CS245i (CSi30) isnt all its cracked up to be either. Not very musical, the CSi40 is by far the best Polk Center I have heard....

The CSi20 is for the R series. If I'm not mistaken that is, however it will probally match your Sony's alot better. The CSi30 may be a class above your sony's. No offense or anything, may be in the same class, no clue really. But I would go with the CSi30. the CSi20 just isnt a man power center. Its baby power, 2 woofers, clearer vocals, better bass, better everything really. It will be way more open in the vocal area, cleaner sound effects, just CLEANER sound.

[dorokusai]

GT - Well I cannot expound on the exact theories, but to the best of my knowledge the CSi30 does not split frequencies between the two(2) bass drivers. They radiate the same freq's. Since Polk at least from the website specifications does not list a dual crossover point, I would presume that this is true.

I think the CSi20 was developed mainly as an entry level, R series supporter. The line certainly needed a center channel option. I wouldn'y say it was a design flaw, Polk probably just wanted to show a range, and give the buyer options.

As mentioned I have auditioned both, and the CSi30 just fills the niche so much better. It has more cabinet volume, better drivers and can handle more information easily than the CSi20. You figure that so much of the surround format is handled by the center channel, 50+%, you need one that easily handles this expectation. I am upgrading my CSi30 to the CSi40 based on this fact. I am very happy with the 30, I just want the most robust center channel I can get. I am mainly HT oriented, so this is important for my application.

I personally would go for the CSi40 now, don't bother with the CSi30 for your center channel. It is really a great sounding center, bass is very pronounced and tight. I have listened to CD recordings in DD and it sounds great, no problems handling the bass. The price has also come down, $299 last I checked from Crutchfield, and thats a good price for a great center channel.

Let me know what you decide, and if you have any other questions that I can try and answer for you.

[GreenTop]

Let us know what you do.
OK. Friday, I listened to the speakers and agreed with both of you, that the i30 is a better speaker. But I decided to buy the i20 anyway, for several reasons:

First, here is the context: A few weeks earlier, I had bought the i20 as part of a special deal from Circuit City, and (due to this "package deal" and the lowered sale price of the i20) returning the i20 would have gotten me only $95 credit toward the i30, so "trading up" would cost $105 + tax. At $150 versus $200, I might have chosen the i30, but it wasn't worth an extra $110.
Also, the i20 is consistent with the "low budget, semi-audiophile" nature of my current system, which is fairly good (I like a stereo system that sounds good, but I love music for the melody, harmony and rhythm, more than for the audio quality) but it's certainly not the same quality as what most of the people in this forum have. And I'll be using the system in a small room, listening at medium levels (not loud) to mostly music (where the center isn't very important, and can even be eliminated) rather than HT.
By the way, I got a great deal from Circuit City -- the Onkyo 501 and Polk i20 together were only $339 + tax -- and I'm extremely happy with the way they treated me. Therefore, I hadn't opened the i20, so that if I did return it for a trade-up, it wouldn't be "opened goods" that CC would have to sell for a discount.

my subjective audio test: I thought the i20 and i30 both sounded good, but the i30 was better. They were definitely different. The i20 seemed a little more warm and mellow, the i30 was more crisp and clean, and it could handle loud volume better. Overall, the i30 was clearly better, but they were both good, and (as explained above) for me in my current situation the i20 was preferable.
Eventually, I may use the same strategy that others, on this list and elsewhere, have described -- using the i20 as a rear-center and getting an i30 (or 140) for the front-center. But not for awhile. For now, I'm very happy with the i20 and my Sonys at the four corners, and a very old AR-18 in the rear-center.

Thanks for your helpful responses.

gt

[dorokusai]

Congrats on your new purchase. If it sounded right for you, then it was right for you.

You can always upgrade your center later, with a CSi30, and move the CSi20 into rear surround duty.

Glad that you took the time to listen to them both, thats what it is all about. Let us know if you need any help on anything, have fun! :)

[fgr41]

I'm glad to hear you found the info helpful and am impressed with your self controle. Myself I always tend to go bigger, ie CSi30. :)

Hope you enjoy, you can always upgrade if you want. Wait till the CSi30 goes on sale and you might even be able to do a clean trade.