A PC connected to a Griffin imic worked very well with my previous CCM 4.2 cluster , the PC played back mp3 songs to a high quality. Now I have upgraded the cluster to CUCM 7.1 and forced to use moh-usb-audio, the quality has diminished. There is a definite background hiss, even when the iPOD / PC is not plugged in and the song itself has a poor quality sound.
I have tried with different mp3 / wav formats and I have played around with the settings within the services > Cisco IP Voice Media Streaming App, such as:
1. MOH Fixed Audio Quality level
3. volume levels
The reason for not using the internal CCM MOH service was because of the poor quality the songs had after they were converted to g711.
Do I have to use the "Cisco" MOH-USB-AUDIO device or are there alternatives, has anyone got the Griffin working on CUCM 7?
We have also seen this issue - we were running CM 4.x and were forced to upgrade to the MOH-USB-AUDIO card with our upgrade to CM 6.x. Using precisely the same audio feed that had zeroquality problems on CM 4.x (with which we used an internal sound card), the new USB audio 'card' (more of a dongle) has very, very poor audio quality. To date, we have not, er... received satisfaction from TAC on the issue. They had us substitute an iPod for our feed, and they noted the quality was better (by some technical measurement they observed), but the observable qualty for the end users was still not acceptable, we explained to them. They seemed unmoved by our pleas. I intend to take up the issue again, once I assemble enough patience to discuss it with them.
I'm not aware of anyone getting the iMic or alternative cards to work - likely due to the draconian controls placed on the configs with CM 5.x and greater (notably, I am in favor of such tight controls and they supportability they enable, but mostly the thing needs to work and this most certainly does not!).
If you find a solution that address the major audio quality problems with the MOH-USB-AUDIO , please do share it here. I'll do the same.
You won't get the Griffin iMic working with any linux-based CUCM simply because the OS and IP Voice Media Streaming App won't recognize the device.
To the original post in my experience hissing is typically caused be a high input gain from the audio source. I'd also look at potential grounding issues on the server itself (or the rack it's mounted in). Since the CUCM has no way to adjust the volume of MOH audio files it can only be adjusted at the source or from an intermediate device.
Sounds similar to CSCtg19173. This documents an issue whereby the MOH-USB dongle has an impedance mismatch with the audio device since the audio device is Line-Out, but the MOH-USB is expecting Microphone, boosting the incoming signal.
The enhancement request is closed, and the recommended solution, as other have pointed out, is to use an attenuation cable.