Question: what is the difference between ac and n routers?
Answer: In fact 802.11ac uses the 5GHz band while 802.11n uses 5GHz and 2.4GHz. Higher bands are faster but lower bands travel further. That said my experience testing both standards finds very little difference in signal strength between 802.11ac over 5GHz and 802.11n over 5GHz and 2.4GHz.