He's not known as a yeller, but can get steamed when an employee falls short.
From the stltoday.com
He wasn't a yeller or a screamer, he was a good teacher, very disciplined.
From the sfgate.com
He's not a yeller or a screamer, which I think is good when you have a young crop of guys.
From the washingtontimes.com
Coach Eddie Jordan can be stern, but he's also not a yeller or screamer.
From the sportingnews.com
If you are not working hard, he'll make you work hard, he's a yeller.
From the democratandchronicle.com
He is not a yeller and screamer, a la Bob Knight or Pat Summitt.
From the sacbee.com
My argument with the non-yeller felt balanced, and productive.
From the timesunion.com
He is an intense guy, but he is not a screamer or yeller.
From the tennessean.com
He's not a yeller and can sometimes seem mellow to the point where people think he's not paying attention.
From the time.com
More examples
Roarer: someone who communicates vocally in a very loud voice
(Yellers) A scream, shout, holler, vociferation, yell, outcry, or steven is a loud vocalization in which air is passed through the vocal cords with greater force than is used in regular or close-distance vocalization. ...