How to protect myself from Spam

[Irresistable]

I'm looking for a single method, that will protect a contact form from spam.

Which is also user friendly.

 

I've looked up on captcha's, the best I can do is one without Audio, which means it's not friendly towards Visually compaired users.

Looking at ReCaptcha, it does what I want it to do, however.. when I create a custom theme, It's hard to validate it, either that or the validation doesn't work. I've not found any answers for it either.

 

I'm most guessing a Captcha is out the question. Though maybe something similar?

For non registered users, I have thought about having the user confirming their email address upon a contact post, before it is sent. Though this could be a problem to bots that have email access.

 

There is possibly Adding and Subtracting options. I have had one, but it wasn't to perfect use. I couldn't create it to an image, and sometimes it had empty digits.

 

I've googled a huge load to find ways. Most suggest captcha's but I can't get one that does do proper audio, and isn't that tricky to change the design of etc.

 

Cany anyone point me in the right way?

Preferably methods that use PHP, if possible.

[corbin]

I believe reCAPTCHA has a listen to option.  It would be an external solution, but it would work.

[gizmola]

I've implemented recaptcha with a variety of frameworks and forums.  Depending on the forum or opensource application it might take some detailed theme or code mods to make it work, but there's no fundamental reason it can't be used by you, despite any prior issue you have encountered. 

[Daniel0]

A lot of spam is done manually by humans. In that case it's better trying to detect and filter spam rather than trying to prevent it.