Marratech – Audio issue with Plantronics 645

This is a rather geeky post!

I was involved in a Marratech meeting to test that a Glow Meeting room was properly configured and working. Marratech is an application that I used very regularly in my last job so it was interesting to come back to it after quite a long break in use – I now use WebEX daily which fufills the same purpose. They both feature the ability to conference using voice and video.

The purpose of this post is to document an issue that I experienced with using the Marratech Client and my recently purchased Plantronics Headset – 645 USB model. This headset cost about £23 including postage and is configured as an analogue device with an additional USB Analogue/Digital audio converter. The headset can be used as an analogue device plugging into a PC or Macs headphone (output) and Mic (input) ports.

I discovered that my MacBook Pro does not have a Mic input – it has a Line-in port which means that it is not compatible with the analogue signal provided by most Mics – this is why I wanted to source a USB based headset. I thought that the 645 model would be flexible in that it can be used both on the USB and analogue ports.

However, on connecting the headset to my Macbook Pro via the USB device the sound was completely wrong – my voice sounded as if the frequency has been increased making it very difficult to understand (bit like Pinky and Perky if you can recall that duo form UK childrens TV some years ago!). I did a lot of experimentation with the configuration thinking that this was a software problem. In the end I found a really simple solution as follows.

It seems that the USB device – combined with the Marratech client program may have been the source of the problem. I connected the Mic from the headset to the USB device and the headphones to the headphone output ( on the computer ) and everything worked fine. The resulting audio quality was very good in my opinion.

So it appears that the Plantronics USB A/D convertor had an issue when it was being asked to do the A/D conversion for both the Mic and Headphones concurrently. I did not try this with Marratech on a Windows machine – I will perhaps try that another day! I was able to repeat this on two Mac Laptops the Intel based Macbook Pro and my older Powerbook G4. There were no notes accompanying the headset to state any limitation in the use of the USB adapter but ther does seem to be an issue – at least when used with the Marratech Client!

Finally – I should add that I was able to use the headset in full USB mode with the Webex Connect Client(VMWare/Windows XP over MacOSX) and also with Audacity OSX native and the problem definitely does not exist there! So I am forced to conclude that the issue is specific to where the USB adapter is being used with the Marratech client ( at least on a MacOSX platform).