Better yet, do the smart thing...
Take whatever income tax writeoff amount you have available and give it to those charities. Then use the speakers as a business expense for your conference room (HT *wink* *wink* *nudge* *nudge*) where you show clients and prospective clients powerslides/presentations of things you are working on. This way you can write that off as well.
Then use the money you didn't waste by just foolishly giving it away without thinking about how to use it properly, and reinvest it in order to make compound interest on the investment and in order to make future investment income. This way you can do the same thing all over again next year when your invested money makes more money for you!
If you just give your money away without being creative, you won't have anything left to give to charity very soon. If you use an intelligent investment strategy, you can keep giving to charity for the rest of your life. Thus you can give a lot more money to charity over the long term, rather than making yourself a charity case in the process by foolishly giving it away without any foresight.
See, you can own the some of the best speakers in the world, such as my Wilsons, and still help save the third world, all at the same time! Go figure!