I refer to a commercial with a supplied voiceover or one you gather and direct yourself. If you are very lucky to be able to have the voice talent with you or have the tie line to direct, you have control of the inflections, the pace and the feel of the commercial.
In commercial radio the amount of on-site announcers capable of completing a commercial voiceover is small. They are not the “classic” announcer anymore, a multi-skilled announcer, with the talent to do a bit of anything.
On air, talent is what you have on station getting you get the best possible results for the program but a commercial read? It might not be the best quality.
When it comes down to it, if you use an agency voice you will get the best result for you on air sound AND the advertiser. You should be delivered 2-3 different takes of the read to get as near as we can do what we want.
Content directors (PD’s to us old guys) do not want their on-air announcers reading ads unless there is a revenue benefit. Make the call, do all your ads with the agency, with the writers writing for a voice you will achieve a better result in the scripting stage too. That translates to the produced commercial coming back crack on what was detailed in the script.
So really for the best for revenue and for the sound.