how to set shipping costs for speakers?

Hi folks, I'm trying to sell a pair of speakers for the first time.  I have the original shipping boxes, how should I enter in the dimensions to factor in two boxes worth of shipping costs here on Audiogon listing?  How do you folks handle double pkg. costs, any seller actually does double pkg. on top of original boxes?  Thanks for helping a newbie seller out.

P.S. and yes email sent to Audiogon customer service too

I think it pays to make the sale easy. I would build in PayPal and shipping in the asking price, so that the customer is attracted to the mention of free shipping and no PayPal fees.  You never see a heavy shipping cost or credit card fee on a site like Best Buy, so better to buck the bad trend on audiogon and include it.  What I do, living in miami, is to calculate shipping to Denver and use that as my base cost that I need to recover in my total proce. If someone from Atlanta buys, I save a bit, if someone from Seattle buys, I lose a little.

if you have large or giant  speakers, that makes it a bit more challenging as the normal services have maximum sizes.  However there are crowdsourcing shipping companies such as youship that can help you run some price options. You can also offer a discount for local pickup.

good luck!
Hi  hifineubee

In my recent experience with selling speakers and using Audiogon's shipping calculator I found the shipping fees they were coming up with were dollars short vs. what the outside estimator or FedEx estimator came up with as the shipping cost. The Audiogon estimator also doesn't factor in insurance as well as special situations like having a signature required. All these options cost more money that you may be on the hook for.

If I was in your shoes I would put in the shipping dimensions and weight in your listing and have the prospective buyers try to figure out their shipping. Also you should put in your listing that shipping will be specified after the listing ends. Be ready to make estimates on shipping. I had the FedEx shipping calculator website on my screen when I was selling speakers.

If the prospective buyer is legitimate and not just a lowballing tire kicker they will do the research on shipping pricing.

Best of luck with your sale.
+1 jedinite. IME,  speaker buyers know they will have to pay for shipping.
Just paid to have a sub shipped to me.  I ended up buying a brand new box from the mfg and sending that to the seller so he could use it to pack and ship the sub to me.  FedEx Ground will transport items up to 150 pounds and this sub was at the limit.  The only reasons I didn't ask that it be strapped to a pallet are that the seller didn't have a pallet, the cost was very high, and the new mtg's box contained protective wood panels.  If the speakers are medium to large, buyers should anticipate the shipping/insurance costs will be in the hundreds of dollars.

To price shipping, you first need to decide how you plan to ship the speakers, i.e., by a common carrier like FedEx Ground or UPS and in their own boxes, or strapped to a pallet and shipped by a freight company.   The pallet approach with freight shipping is by far the safest for large heavy items, but it is expensive.   I would then look up a couple of estimates based on the item size/weight and both near/far ship-to destinations, so you can provide buyers rough estimates of what they will be paying.  I would then clearly state in the ad that the actual shipping and insurance costs will be the full responsibility of the buyer.

I would not sell to somebody who does not want to fully insure the shipment.  Speakers are heavy, large, difficult to carry and the most commonly damaged audio equipment when shipped. 
Therefore, if you can hand-deliver them that would be best, and that is the only way I have sold large speakers so far.  I am getting ready to post another pair of 100 lb+/each speakers for sale and I will be offering free delivery to three states that I travel to for work, if the buyer is willing to coordinate with my travel schedule.  Otherwise I will have to decide whether I will be comfortable with FedEx Ground in the original boxes or whether I will insist on strapping them to a pallet and freight shipping.  I would rather lose a couple of hundred dollars because of a high shipping cost than to have one speaker damaged in shipping and a buyer who insists I take the pair back.
before you choose to include shipping costs, the cost can vary tremendously with distance, even for smaller speakers...I think Audiogon offers the option of arranging actual shipping cost after the sale...
Thanks for everyone's feedback so far!