I can't find a box to ship my speakers,,,,,,,,,,,,

Klipsch can get you a boxes--they're not cheap. You will wonder if they are made of carbon fiber to reduce vibrations in travel for what they will charge you. And they really are not ripping you off--boxes are surprisingly expensive. Conversely--and quite oddly enough, I had crates made for my Martin Logan Monoliths out of wood and styrofoam cheaper than boxes cost! Look up some crating companies in NYC--there's got to be dozens of them, and get them to make you a crate. Yes it will increase the weight--but will also protect the speakers far far better than any cardboard box (you can ship them ground freight too--and that will be cheaper).

Think "outside the box" and hire a carpenter...

Most Mail Boxes etc and other packing stores have people who crate for them, I wouldn't recomend using them to ship as they are expensive, but with a little tack you might find out who makes their crates.....

I have had really good experience with www.associatedbag.com
They have a lot of shipping supplies. Not sure about your particular size. But they have been great to work with on the phone, and very quick too. I needed a sample to verify my need, called on Friday, it was on my porch Monday. I have compared prices, and they were the cheapest too. Another option is your local U-haul should have these boxes they call "mini-wardrobe", which are quite large and could easily hold a large speaker if packed appropriately. They are around $7 each.

Use a carrier and send them as a "pallet" shipment. Most major carriers, even moving companies will do this. It isn't cheap but neither is UPS. That way, all you have to do is cover them with a packing blanket and strap them to a pallet. A fork lift does the rest?