help on center speaker

Ok, let me make sure I understand this correctly: if you setup the speakers to full range (large speaker in the NAD's setup), the low frequency will not be cut for those speakers - for example my Linn Index's low range I believe is from 60 Hz. The rest of my speakers have a low freq range of 80 Hz.
In this case do I want to set the sub crossover to 60 Hz and front speakers to LARGE or I still have to set the sub to 80 Hz with front speakers to LARGE?
My intuition tells me that the second setting is the correct one.
Thanks a lot for the help!

OK I am new here and I have few problems:
just got my NAD T753 (Linn Index in the front, Linn Afekt sub, Linn Unik center, Denon surround sound) - I know not a perfect setup, but I am in the process of upgrading.
1. Why do we need to buy expensive "full range speakers" when we are going to set the subwoofer to take care of all of the frequency below 60/80 Hz? This is not making sense to me... any help please? I believe a good sub with cheap speakers will do the job as well. What am I doing wrong?
2. The NAD T753 does have the hush noise and it is noticeable... I have also an old (10+ years) NAD 302 integrated amplifier and the sound is much better compared to the T753. Is this the end of the NAD era?

Thanks for you response! So I guess the solution is to use my old NAD 302 integrated amp with my Linn Index speakers for listening to music (NAD 502 cd player), and setup the NAD T753 receiver for home theater using the Linn Afekt sub and 6 low priced/not full range speakers - for example 6 Linn Unik ($225 a piece). It does not make sense to buy good/full range speakers for home theater and then to send all the low frequency to the sub. I think this should be my target - I just need to find 5 more Linn Unik (have one already) and I should be good to go.
Thanks!

I will keep it at 80 hz and small speaker setting, until I upgrade my front speakers.

So I guess in this case I have 2 options:
- Upgrade front speakers: I am thinking of the Linn Ninka (50Hz-20KHz), then set them as full range front l+r and crossover the rest of the speakers (Linn Trikan in the center and 3 Linn Unik in the back). Also the Ninka are matched to the Trikan center speaker. A bit expensive, but I will try to get them used. If I get the Ninkas I am thinking of also buying a better power amp (NAD THX 216).
- Buy a second sub (Linn Affect) - this is a cheaper option - used can be found for like $700. The only problems is that my receiver does not have l+r outs for the sub (it has only sub1 and sub2).

I am thinking that option 1 is better. Any ideas?

and regarding the center speaker - I got the Linn Trikan.

Markphd:
What amp/receiver are you using? I am just currios. Regarding the 6.1 - I am not crazy about it, but I will be ready for the future, and I don't have to upgrade any time soon.
As for me I will stay for now with the Index/Trikan/Unik/Afekt speakers + NAD T753. I think next upgrade will be the front speakers - I thinking on the Ninkas as well.