Distorted recording when using overdub

I am using audacity 2.0.2 on a PC running Windows 7 professional (64 bit)
Whenever I go to record something, everything that I record using overdubbing comes out heavily distorted. Recording single tracks is fine but I don’t want to do everything like that because it makes what I record sound unnatural. This problem also occurred in the previous version of audacity that I used (1.3). The equipment that I am using is a Alesis multimix 4 connected to the computer via USB cable. the mixer has a microphone, keyboard, electric drum-kit and acoustic guitar connected to it although I don’t think that they are causing the problem because I have used them in several different orders and configurations and all of them have the problem. it isn’t simply that the gain is set to high because the settings are the same as they were for recording the previous tracks.
Thanks for your time,

See this topic: https://forum.audacityteam.org/t/mic-to-headphone-latency/26412/1

Thanks for replying but the issue you linked to is dealing with latency. I appreciate that we are using a similar bit of hardware. but our problems are totally different.

Sorry, I should have said, see this post: https://forum.audacityteam.org/t/mic-to-headphone-latency/26412/9
I know that the topic is different, but that specific post is probably relevant.

If it still does not make sense or you don’t see the relevance, please describe in detail what you have plugged into where, what settings you have in the Device Toolbar and precisely how your mixer is set up.

Basically the Alesis multimix does not seem to be very good for overdub recording with Audacity, but if I know exactly how you have it set up I may be able to help you to get it better than now.

If you like to record YouTube audio or other internet services, you might forget to change your Audacity input back to a physical device and not the internet service. The upshot of that will be multiple recordings of the same thing. Recording track one will give you track one, but recording track two will give you track one and track two. And so on up. If you like to record hot, that will cause high volume overload in rapid order.

Inspect the Windows Control Panels and Audacity Preferences and make sure you’re recording a specific physical device and not Stereo-Mix or WAV-Out.

Also check sample rates are the same everywhere: http://manual.audacityteam.org/o/man/faq_recording_troubleshooting.html#sync .