Echo call to VLC bash using subprocess.Popen on Linux

[LuukS001]

I am using this both on my macosx and linux and it works well.
On linux the shell commands are slightly different:

vlc -I oldrc --rc-unix=/home/user/Documents/Sockets/socket1.sock
vlc -I oldrc --rc-unix=/home/user/Documents/Sockets/socket2.sock

and

echo play | nc -U /home/user/Documents/Sockets/socket1.sock
echo enqueue /home/user/Documents/DualscreenVLC/videos/MVI_2534.MP4 | nc -U /home/user/Documents/Sockets/socket1.sock

I am attempting to use subprocess.Popen in Python for further control but here I run into difficulties on Linux (Ubuntu). It either hangs on the stdout.read() call or when I take this away, all the shell commands are only executed after the script finishes and I get a broken pipe error. The issue seems to be specifically with the 'echo' commands. Did I migrate wrong?
This is the python script:

import subprocess
import time

Socket1Location = "/Users/user/socket1.sock"
Socket2Location = "/Users/user/socket2.sock"
video1 = "/Users/user/Documents/Scripts/DualscreenVLC/videos/video01.mp4"
video2 = "/Users/user/Documents/Scripts/DualscreenVLC/videos/video02.mp4"

def RunVLCCommand1(cmd):
    p = subprocess.Popen("echo " + cmd + " | nc -U " + Socket1Location, shell = True, stdout = subprocess.PIPE)
    errcode = p.wait()
    retval = p.stdout.read()
    print "returning: " + retval
    return retval
    
def RunVLCCommand2(cmd):
    p = subprocess.Popen("echo " + cmd + " | nc -U " + Socket2Location, shell = True, stdout = subprocess.PIPE)
    errcode = p.wait()
    retval = p.stdout.read()
    print "returning: " + retval
    return retval

subprocess.Popen(["/Applications/VLC.app/Contents/MacOS/VLC","--rc-unix=/Users/user/socket1.sock"])
subprocess.Popen(["/Applications/VLC.app/Contents/MacOS/VLC","--rc-unix=/Users/user/socket2.sock"])

#RunVLCCommand1 and 2 can now be used to send commands to VLC, for example RunVLCCommand1('play')