The sound quality of my default sound files such as Agent Login and Voicemail Prompt are very bad quality. Sound quality on phone calls is great.
Am I missing some package?
How can I change the default agent login prompt to a customized .wav?
Please help this is the last step until depoyment!
I guess you mean that the quality of those files is bad when you play it on computer right? If this is correct, that is right - phone quality is 8khz and therefore asterisk voice prompts are 8kHz, which would sound very poor on PC speakers compared to MP3 music, which is 128kHz.
In another words, those prompts are intended to be played on the phone, so you can’t enjoy playing them on PC speakers 
To change any of the prompts, record an audio file at 16bit, 8kHz, mono, name it according to the filename of desired prompt, save in .wav format, make bakup of original file located at /var/lib/asterisk/sounds/ and put the recorded file in that directory.
thanks for the response on how to change sound files. I actually have it going to a cisco 7940 but the sound is still bad. My server is virtual and without a soundcard. I think it may be because I didnt correctly setup ztdummy? I am going to recompile tommorow with zaptel and ztdummy correctly configured and see if that fixes it.
Okay I see, so the sound is bad on the phone.
Are the original sounds in wav format?
What codec do you use? is there a conversion done?
How is Cicso connected to asterisk?
Is conversation quality better than prompts?
drop some more details
What a shock! Poor quality sound on a virtual server.
I am a huge VM fan - almost 90% of my servers are virtual but my phone server is one of the 10% the is not and will not be virtualized.
Asterisk is a realtime app and needs resources in realtime. Anything that gets in its way will cause voice quality issues and that includes other programs ruuning on the same box or middlemen between the OS and the actual hardware (i.e. Virtual Machine software). That one or two milisecond delay between the actual instruction and result that VMware ESX will give you will cause issues. If your running any other version of VM software (VMware Server (free version), MS Virtual Server, etc.) you see that 1 or 2 millisecond delay become 5 to 10 times that!
The great thing about Asterisk is you can use a single processor machine with 2GB RAM to support hundreds of users. An old desktop with 512 MB RAM will support probably 20-50 users so there is really no cost benefit to virtualization.