I pretty much always have the HP engaged on the SM7. I can't think of an instance when it was off right now. I always use an external pop filter (the high end seems way better to me that way). The presence peak is totally based on the singer. I find that singers who have a thicker voice with a lot of over tones need the presence peak. Singers that have a cleaner voice can start to sound to small and mid rangy with the presence peak on. Here are some examples of singers that were definitely one way or the other for me:
Adam Lazzara - peak on
John Nolan - peak off
Steve Harwell - peak on
Myles Kennedy - Peak off
Chris Cornell - Peak on
Sara Watkins - Peak off
EV
SOURCE
