Mincone, I could (and should at some point) compare them directly but it would not be a fair comparison and would not answer the question you are really asking. The RTi8 is rated (+/- 3 dB) down to 40 Hz (just like the Monitor 70) as it is a floorstander while the M22 is a bookshelf rated only to 60 Hz so the RTi8 will have a better low end than the M22 just like the M60 (37 Hz) will have a better low end than the M22. Many people here find their M60s very enjoyable for music without a sub and I suspect you would, too. Although I haven't personally heard it, based on my experience with the M22 I feel confident saying that the M60 is an excellent speaker. I wish I could compare it to the RTi8 to answer your question, but alas...
If the low end sound coming from the main speaker means that much to you, look at the M80 (34 Hz).
