@BondSPB - This is what we normally do:
1 Either record the IVR greeting using a phone that has G722 turned on so that the original recording is in HD, rather than upscaled to HD from G729… which won’t sound good.
OR
2 Record the IVR greeting using a high quality Mic (like the Blue Yeti), saved to the computer and uploaded in high quality MP3 format to let it transcode to ulaw, g722, etc.
In general the rule of thumb is record in as high of a quality as possible before transcoding. I also suggest hiring a company who can do professional IVR greetings as that really makes any company sound like a million bucks for the price of it.