SELECT "Horizontal order" FROM table_73539 WHERE "Channels" = 'WXYZRSTUVPQ'
If the channels is wxyzrstuvpq, what is the horizontal order?
CREATE TABLE table_73539 (
    "Horizontal order" real,
    "Height order" real,
    "Soundfield type" text,
    "Number of channels" real,
    "Channels" text
)