Lsi-C and Rti-8 Combination

MusikSource

Hello all, I recently purchaced the Lsi-C center speaker and a 2 pairs of Rti-8's. While I have yet to recieve them, the sale is final. After a seccond review of the speakers specs I realised the Rti-8 are rated at 8 Ohms and the Lsi-C is 4. I will be powering these speakers with a Onkyo TXSR705, 700 watts RMS total, 100 Watts/Channel. First off I wanted to know if I have made a terrible error combining the Lsi and Rti's together. Seccond, can anyone offer any feedback as to whether or not the Onkyo reciever will provide sufficient power to these speakers.

john22614

You can calibrate the Onkyo so it will compensate for the difference in ohms....make sure you set the center to small and you should be ok. I actually had the opposite situation for a while with LSi9's and a CS400i center, and it was fine. I got the LSiC later because it was smaller and I needed more space in my cabinet.....plus it was a perfect sonic match. But, I found that the 400 was fairly close to the LSi's, and suspect you will find the RTi's and LSiC do pretty well together also. The difference to me was not that great, I think mostly because they are both good quality speakers made by the same company and already share many sonic characteristics, Your Onkyo should drive them ok,....however, at some point you may want to get a separate amp to get the best performance. You also may find you want to listen to music in stereo....that will certainly take some of the strain off of the AVR....most people prefer listening to music that way anyway. Also, you get the benefit of really good sounding dialogue for movies with your LSIc.

mantis

I wouldn't do this combo. You should have a Rti center channel.

Dan

MusikSource

Thank you john22614 for your feedback I much appreaciate your input. You will have to forgive me as I am not that savy in my old age when it comes to most of this. Would you or someone kindly explain to me what you mean specifically when you say "separate amp to get the best performance" Do you mean a whole new amp or ad to the one that is already in place? You state I can calibrate the amp to compensate by setting the Lsi to small. s this all that will be required or will I have to calibrate further. Can you also explain for me what setting the Lsi to small will acomplish? I am sorry if I am asking to much!

McLoki

Start with the basics - a Reciever or AVR is 3 componets in one.

1. A preamp/Processor (lets you control volume, switch sources and decodes things like Dolby Digtal and DTS)
2. A Tuner (lets you listen to the radio)
3. A amplifier (takes the low level signal from the Tuner, Processor or anything else connected to the RCA jacks in the back of your reciever and amplifies them with enough power to make the speaker vibrate and create noise.)

Your Onkyo Reciever has output RCA jacks on the back of it that will allow you to take the low level signal before it is sent to the amplifier in your reciver and send it to an external amplifier for any channel you have connected to it. (you would then hook the speaker for that channel and to the external amplifier)

The onkyo will be fine for your RTi8's. It may be ok for your LSiC but that will be the more difficult to drive. If it has problems with your LSiC, you can connect an external amplifier and use that to power your center channel. (while still using the amplifier built into your reciver to power your RTi8's and any other speaker you have connected.)
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By setting a speaker to small, it will send the bass signals (the signals that require moving the most air) to the subwoofer if you have one connected or your front speakers if they are set to large (and do not have a subwoofer connected). Setting a speaker to large or small in the reciever has nothing to do with the physical size of the speaker, rather do you want it to try and reproduce the full frequency range (when set to large), or do you want it to allow another dedicated (subwoofer) or larger (front speakers) to produce the bass for it so it can concentrate on the higher frequencies that it is more designed for (when the speaker is set to small).

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If you are new to the entire home theater thing, Polk has a number of very good articles that serve as an introduction to home theater. They are free downloads and you can get them here.

They have alot of good information in them and are a pretty easy read.

If you have any other questions, feel free to ask and welcome to Club Polk.

Michael

john22614

Musiksource,

Michael has given a very good explanation.....I will add just a couple comments. Calibration applies to volume, distance and frequency settings. Frequency settings are the crossover at which bass rolls over from your center to either you sub or your mains....80hz or 90 hz is typically the "small" setting used, and in your case should be fine. Setting the center speaker to small reduces the amount of current needed to drive it, redirects the bass to the larger speakers and puts less strain on the AVR. If you are using a powered sub, set all the speakers to small and let the sub do the heavy duty work. This will lighten the burden even more on your AVR and give it greater capacity for the mains and center. Since 4 ohm speakers require more power to achieve the same volume as 8 ohm speakers, you will need to adjust the volume up on your center accordingly when you run the test tones. You can do this by ear or using a meter. You will probably find that it will need to be set about 6db higher than the mains to compensate for the difference. And, welcome to club Polk....if your experience is anything like mine, you will have a lot of fun learning about this stuff.

MusikSource

Thank you both very much. I have read your feedback in detail several times and feel I may have a hang of the situation now. Guess it would have been simpler if I had just done my research properly in the first place and bought a center speaker to match the Rti's or spent a few more dollars and upgraded to the 805 in the matching series of Onkyo AVR's. I wil do my best to work with what I have and hope for no serious meltdowns. Thank you for the welcome I am pleased to be here. If anything I got right it was the choice to purchace the polk speakers.

MusikSource

I turned in my tx-sr705 for a tx-sr805 this is 130 watts/channel rather than 100 watts/channel. I am hopping to power all speakers with the one amp rather than running my lsi-c seperatly. Will this make a significant enough differeance or would you still suggest amping the center seperately?

I am also looking at purchacing a new sub. I was looking at the Polk line however a local audio shop is advising me to consider a Velodyne with a price point of 699. Would you be able to offer advice or any suggestions.

McLoki

The additional watts will not make alot of difference, but I believe the 805 has quite a bit more current capability than the 705. Based on that, you should be able to drive everything from the 805 with no problem. Keep the switch on the back of the 805 set to 8 ohms and give it some room to breath...

john22614

Good move on the trade.....I think that will give a fuller and crisper sound to the center as well as your mains. I suggest you go listen to subs at your price point....one of the new Polks or Velodynes will excellent. Many of the guys here love the Velodynes. Martin Logan makes a cool little 8" Mighty Mo that you might want to check out. Very musical and strong, but not too big. I don't think you will need a separate amp for the center. Keep us posted on how you like it when you get it all set up. Enjoy!

MusikSource

So after going through all of this I just came to the point where I just had to stop fretting about the mismatch between the lsi-c and rti8's and just went out and bought a Csi A6. I thank all of you for all your effort and assistance in this matter. However I ordered the Lsi-C online it is new in the box and I am not sure what to do with it as returning it will cost me allot for shipping and restcking charges so, I plan to put it on ebay but whish to offer it here first if any one would like it I will sell it for what I paid for it at $385 plus the shipping of your choice. Please message me if you are intrested and we may be able to make a deal.