10.11 beta 3 took sound away from me

You might need to do an SMC Reset. How you do it depends on the kind of Mac you have:

On Mac notebooks with non-removable battery

Mac notebook computers that have a battery you should not remove include: MacBook Pro (Early 2009) and later, all models of MacBook Air, MacBook (Late 2009), and MacBook (Retina, 12-inch, Early 2015).

To reset the SMC:

1. Shut down the computer.
2. Plug in the MagSafe or USB-C power adapter to a power source and to your computer.
3. On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
4. Release all the keys and the power button at the same time.
5. Press the power button to turn on the computer.

On MagSafe power adapters, the LED might change states or temporarily turn off when you reset the SMC.

On Mac notebooks with removable battery

Older MacBook and MacBook Pro computers have removable batteries. Learn about removing the battery on MacBook and MacBook Pro.To reset the SMC:

1. Shut down the computer.
2. Disconnect the MagSafe power adapter from the computer if it's connected.
3. Remove the battery.
4. Press and hold the power button for five seconds.
5. Release the power button.
6. Reconnect the battery and MagSafe power adapter.
7. Press the power button to turn on the computer.

On Mac Pro, iMac, Mac mini, and Xserve

To reset the SMC on Intel-based Mac Pro, iMac, and Mac mini computers, as well as Xserve:

1. Shut down the computer.
2. Unplug the power cord.
3. Wait fifteen seconds.
4. Attach the power cord.
5. Wait five seconds, then press the power button to turn on the computer.

im on iMac, did SMC but nothing had changed unfortunetly... As i said im ran out of an ideas ...

As im entering the preferences of an audio nothing shows up in the section output

NVRAM settings can also affect sound, though not normally like your seeing. It's easy to see if it's the issue though - just restart holding Holding down Command, Option, P and R keys as you switch on and hold them until you hear the restart sound a second time.

Did it earlier, cause i thought about it too, but the strange thing is that after clearing NVRAM i heard restart sound, but when the whole system boots up i still dont have any sound, maybe system havent installed drivers properly?

You could try resetting the audio driver. In Terminal copy-past the following:

sudo killall coreaudiod

Ok i did the thing but nothing changed i think...

Oooh... Interesting. Try:

sudo launchctl start com.apple.audio.coreaudiod

also the same result

EDIT

But if ill connect bluetooth headphones it is working, but if headphones with jack its still not working.

I cant think of anything that can cause this.

I cant even reinstall the system -.-

Well, since it appears your missing core system drivers, you're going to have to start from scratch and install Beta 1 to a freshly formatted partition. As you're probably aware, you then need to update to Beta 2 and then to Beta 3 (not skipping Beta 2) because only the first Beta is a full OS, the other 2 just change and add bits to it. If you have any trouble with this process, you can refer to my post here:

https://forums.developer.apple.com/message/22474#22474

Unfortunelty the instalation of this .pkg cant be completed

Which .pkg?

Firemware and recoveryHD which should be installed before main beta 2

Did you download the Developer Beta fresh from Purchases or are you using the one from before Beta 2 came out - Not that they're necessarily different - but I just want to check something...

ive updated it OTA, im on beta since beta 1.

The strangest thing is that sound is working perfectly in recovery mode when i was choosing language (the're speaking in each language) but no in normal mode nor in safe mode...

That's odd, I think your the first to report that error message on trying to install those packages - the firmware one I can understand as not all Macs will always need all firmware updates (they're meant to be able to know what machine they're running on and act accordingly), but the RecoveryHD one surprises me.

I can only suggest that you push on regardless. Does Beta 3 appear for you in the App Store now?