I have a HTR-5640 and my sub will switch on but I don't get any base out of it no sound! Even when I do the speaker test. Is this a setting or is there a problem?

If you remove the signal cable from the amplifier while the Sub is switched on (turned down about half way) you should hear a thump sound. If you do that proves that your sub is working and you need to look at your Yamaha. Perhaps the sub channel has been disabled in the logic settings. Check the speaker configuration pages. If all looks well reset your amp to factory settings and try again. I have had a logic glitch which was fixed in this way.

configure ur PC (both OS audio and third party sound driver) for surround sounds. control panel- sounds and audio devices - speaker settings - advanced - speker settings. so this done. make sure u select the 6 input channel - the button is on the right edge near the volume knob. near the vol button there are two buttons for selecting input type with up down arrow. from that u can select the input type this will be indicated on the top front indicator. but with the 6 input channel selected all selections are preceeded. if u select stereo mode u will have left/ right audio only.
make sure u connect the input right. connect from computer to 6 channel input. main, surround, center and sub-woofer.  connect the spekers to main (L/R), rear(surround) (L/R), center and sub woofer to terminal marked sub woofer ouput. this done select like i said before the 6 channel button. that should do it.

is the tv set to mono or stereo?

First, look at the sub, their should be a switch for "auto" "off" "on" switch it to "on" Then use the Left input on the sub not the right. Left is for mono. Now, if you still dont have any sub, disconnect the RCA at the receiver and touch the end of the RCA, if the sub is on, you will hear a loud humm. Now, go back into the receivers Menu and go into manual setup, find "Audio" and select "Auto". That should do it. If not, put the receiver on "Tuner" and set the sound to 7 channel stereo (I'm not sure if the HTR series has this) or "Adventure" I'm a Yamaha RXV series Dealer so the names may differ. (check in manual for audio surround settings) Anyway, this should let you know if you've got all your spkrs working. Then make sure your TV's external audio is set to "Fixed" (it may be called audio out) depends on TV type. Scroll thru TV's audio menu. If you still have problems post a comment and I will help some more. Hope this helps

is there a switch in the back for surround on/off

there are many settings 1.distance (This is the distance between you and the speakers) if your sitting say 6 ft away then you set it to 6 and so on (all front speakers should be lined up the same distance from you) The rear speakers are set up the same way (distance from where you are sitting) then 2. small and large (always pick large for best sounf)3.Tone (this is more a matter of choice) play around a bit with it! the sub should be at least one foot from the wall for best sound! I keep my center chanek a little lower then the other channels for best sound !

MAKE SHURE YOU HAVE TOLD THE AMP YOU HAVE A SUB IN THE SET UP MENU UNDER SPEAKER SETTINGS.
IFF YOU ARE USEING SMALL SPEAKERS THEN SET THIS IN THE MENU AND OUT PUT BASS 2 SUB ONLY ,SET XOVER ON AMP IFF U CAN 2 120HTZ, ALSO CHECK THAT YOU HAVE THE SUB CABLE PLUGED INTO SUB OUT ON BACK OF YOUR AMP ,AND NOT THE 6 CHANNEL INPUT.
HOPE THIS HELPS.

CABLE GUY.

Select different modes on the remote or front panel and make sure all speaker that you have hooked up are showing on display. Are the Lt & Rt channels at least playing audio? If you want, i can step you thur some steps to try in live chat if you want today. Let me know as i have experience in this area! Sincerely Guru Jay

adjust your sound outputs with the remote and adjust the +/- settings on them and ten try another sound output adjust the stero effectsand try playing around with that and try cutting the speaker cable back about 2 inches and using a new peice of the cable to see if it's the cable causing the issue.

try splicing your cables to the speakers back about 2-3 inches check all you componet cables to make sure they are all "all" the way in and re-wire the speakers into the jacks, cause anything mildy out of place can casue the other speakers to cut out