Tax (GST / HST) will always be applied to most products regardless of where you order them from.
The next question comes to duty, and that depends where a product is made, If it's made in Mexico or USA, it is protected under NAFTA and you should not be paying duty. If it's made elsewhere, you're paying duties regardless - they're simply internal to the cost of the product.
Cross-border shipping fees are usually pretty reasonable via ground, but via air usually adds brokerage fees into the price. Ground will also add brokerage fees if you do not self-clear, but in most Canadian cities with an airport, self-clearing is a total cinch.
Realistically, I wouldn't be too bothered by ordering from USA. Yes, you will pay a bit more, but it's just the way it is. Most of the well-known entry-to-mid-level ID companies (EMP, SVS, Ascend, Salk, Philharmonic, Wavecrest) are still extremely high-value, even if they cost more to Canadians than to Americans.
FWIW, I'll toss out this site:
http://www.pashop.com/products/detail/JBL/LSR305/