How do I hook up a Yamaha RX-V377 receiver to a Samsung HW-H450 soundbar?

OK, If its the Samsung Sound Bar, this item should have 2 HDMI input, 1 3.5mm audio jack input and a digital audio input (fiber optic). Since there are various input, the remote control should have a source button, or it will probably read O/A Input, this is to change thru the inputs from the sound bar. If you connected your TV HDMI output to HDMI 1 from the Sound Bar, then press the source button to reach HDMI 1, maybe it will be display with a different name, like sound 1, or DIGI.1 Give it a shot and let me know in the comment section. Good luck.

yes, hdmi cabels carries audio signals as well as video.

Really depends on what you're switching. If you plan on using a DVD, Cable/Satellite receiver, or more than you'll want to plug all those sources into the HDMI inputs of the TV. From the TV you'll want to run an SPdiF cable to the back of the sound bar. These cables can be had for less than $6 on Amazon unless you have one already. This is the simplest and cleanest way to use the soundbar as the TV's speakers. Go to MENU on the TV and select AUDIO and then turn off the TV's speakers. This will enable the SPdiF output to the soundbar.

have you tried a different hdmi input ?

If your SAT Box has multiple outputs, hook the HDMI output to your receiver so you can get full surround on movies etc. Connect the HDMI out on your receiver to an HDMI input on the TV. Run a composite or S-video connection from the sat box to the TV for regular TV viewing/listening without the receiver & speakers. I don't think you can get full HD over either of these cables, but you may be able to use the composite connections if they are available on your sat box and TV.

Because your TV is not Bluetooth-enabled and you are trying to connect it to a Bluetooth-enabled soundbar via Bluetooth. There are other ways to connect your TV to the soundbar:

1. analog AUDIO OUT (L/R) of your TV to the AUX IN on the soundbar (use a 3.5 mm.-to-RCA audio cable).
2. Optical OUT on your TV to Optical IN on the soundbar.
3. HDMI port to HDMI port (this may not work if your TV is not ARC compliant you have to try).

You get better sound quality with option 2.or 3. (if this one works for your TV)

Here is the link to download the soundbar's User Manual for help with the connections:

http://downloadcenter.samsung.com/content/UM/201411/20141114104022428/HW-H450-ZA-1114_Bookmark.pdf

Here is a link to your product description. When you get to the web page, click on the "Manual" tab to read the user's manual to find out how you can connect your soundbar to your TV.
HW H450 Wireless Audio Soundbar Samsung Home Audio

HW H450 Wireless Audio Soundbar Samsung Home Audio

Click on the "Manual" tab to read hook up instructions, etc.

can I hook my yamaha rx-V465 to my vizio soundbar? When I soldered the rca plugs on to the speaker wire and connected my center channel on the receiver now ther receiver randomly shuts itself off.

It has two HDMI inputs and one HDMI monitor output for the TV, so assuming all your devices are HDMI-capable, YES.

http://www.crutchfield.com/p_022RXV463/Yamaha-RX-V463.html?tp=179&tab=features_and_specs