Buying in Canada

Must declare purpose of visit; business or other. Upon return to US, must report to customs any items purchased (with receipts) and the value. Big ticket items will be inspected and possibly checked for current market value.

worst case scenario...returning from Canada with top of the line speakers and declaring their value too low to avoid paying customs charges. You will be interviewed.
I have first hand knowledge with undervaluing a Harley.

Thanks Lowrider. I wasn't to sure about the customs charges
for a personal purchase or how it was done.

You should google US Customs fees. You are allowed up to a certain amount without charge. But I'll bet HiFi gear is over that limit. cheers.