When a guest comes to your studio to be interviewed, you have full control of the sound quality: He will be in your acoustically-treated room, speaking into a microphone of comparable quality as your host. He will be listening through headphones fed from your mixing console. Only the callers on the telephone are of lower sound quality.
The show will sound great.
But for those times when the guest can’t come to you, his sound may be compromised. You don’t want to do a whole program with your important guest limited to telephone quality sound (or even worse… hands-free speakerphone). Here are some ideas to keep the guest sounding as good as his information (we hope his information is good… well, we’ll make him sound great anyway).
Many “experts” that have special knowledge in a particular field, may also produce a podcast of their own. If so, ask him to connect to your studio through his podcasting equipment. Depending on the gear he has available, the sound improvement can be modest or dramatic. At the least, you should notice a reduction of the ambient sound of his room, and a consistent sound level with no peaks or drop-outs.
If you can both connect through a high-quality IP codec, or a VOIP service (like Skype), you will also have near-studio-quality sound.
Even if your guest doesn’t have a podcast setup of his own, he can still connect via Skype over most smartphones, tablets or laptops. However, it is important that the guest uses a wired headset/ microphone. This one step will greatly improve the sound quality of your connection. A gamer’s headset with USB or dual audio cables will give pretty good results (but may lack some fullness in the lower registers of the voice).
If the guest has no gear, but you plan to use him frequently, you might want to supply him with a USB microphone. (I’m particularly impressed with the Blue YETI-PRO.) When he connects to your studio over Skype, the improvement in quality will be striking.
Even a simple set of smartphone earbuds with a built-in mic will help. Just be sure the plug has 4 metal parts as shown here. This ensures that the voice will be picked up by the earbuds’ microphone, instead of the computer’s mic. The mic on the earbud cable is much closer to the sound, and will stay at a consistent distance.
Any of these techniques will be a great improvement over a standard telephone-quality call. Do what you can to deliver the best possible quality to your listeners. They will notice the difference.