Skip to main content
UsabilityNews.com - for all the latest in usability and human-computer interaction
BCS Interaction
 
 
The All the Latest section presents all general usability news articles


 
  advanced search
 
all the latest

Caroline's Corner: Getting the Video to talk to the Audio


Source: UN, 31 January 2003
Submitted by Caroline Jarrett

The call from the client was "Can we borrow your camera? We've only got one, and we need two for the next test". We agreed a modest fee and the deal was done. Or was it?

Close questioning revealed that they were planning 'Wizard of Oz' testing on a voice application. The participant would be in room A, with a scenario and the option of filling in a paper form or going direct to telephoning the answers. An evaluator would be in room B, with the script for the eventual voice response system. The observers would be in room C, and wanted to view the participant and hear both sides of the telephone conversation.

OK, so we can have two televisions in room C. By running a cable, or using a video sender (mine's a cheap-and-cheerful Thomson VS530CU) and the observers can see what is going on in rooms A and B. But hang on, that means they'll have two separate recordings from the two cameras so how are they going to co-ordinate them when they're viewing the tapes later?

Hmm. My first thought was 'video mixer', but the video mixer takes a picture from the second camera and mixes it with the picture from the first camera. The evaluator confirmed that she only wanted the sound from room B, not the picture.

Second thought: there must be an audio mixer that works like a video mixer, but for sound. OK, ten minutes on Google and a few quid and I'm done.

But no, my searching finds plenty of software for mixing sound on the computer - no dinky little box that will do the job without a computer. Looks like a trip to Tottenham Court Road is going to be needed.

As I'm packing up to go, a thought struck me. Surely this is what stereo was made for? Instead of plugging a single, stereo microphone into the camera, why not pick up the left channel from the participant and the right channel from the evaluator? I find the two mono microphones, a cable that converts two phono connectors (that look like this) to a stereo mini-jack, and a selection of extension cables. Off they go to the client. Wish I could be there to put it all together but it seems easy enough so I'll wait for the phone call that confirms it.

You've guessed: it didn't work. Panic phone call to the sound engineer who helps me out on these things. It seems that the stereo microphone I have been using has its own internal power source, whereas the mono mics need to pick up power from whatever they are plugged into. The video camera mic input doesn't give a power output.

So now I need two powered mics. I have a one, and the client has an identical one - both stereo. Each outputs a left channel and a right channel. We'll put the left channel from one mic into the left channel of my two-phono-to-stereo-mini-jack adaptor, and the right channel from the other mic into the right channel of said adaptor. All we need is two adaptors that go from stereo-mini-jack to two phono, and I've got one of them. Off to Tottenham Court Road. While I'm there, find out that I can get an audio mixer suitable for a DJ - lots of outputs, only one mic input, so that's no good. Or I can get an audio mixer suitable for a musician: zillions of inputs, much too complicated for what I need. Instead, I hand over £4.99 for the missing adaptor, zoom back to the client's office, plug the microphone for the evaluator plugged into a long extension cable that I happened to have already, and it's working.

Apart from the buzz. But the buzz seems to go away if we check that everything is plugged in really, really tightly. We pack up and arrange to meet at the hotel where the client is testing.

A couple of days later… it's the morning of testing. It's working - or is it? The buzz has returned. Fortunately one of the observers has an idea: maybe the 'spare', dangling phono plugs from the unwanted channels are causing the problem. When we ground them by touching the point of each spare plug to the metal sleeve of one of the plugs in use, the buzz diminishes or even disappears. Liberal use of masking tape to hold them in place and the client's testing can go forward.

So that was easy, wasn't it?

Anyone with a sensible solution to this problem: please email caroline.jarrett@effortmark.co.uk

P.S. The voice application tested pretty well.

Caroline Jarrett
Independent usability consultant specialising in forms, questionnaires and data capture.

Effortmark Ltd
w. www.effortmark.co.uk
e. caroline.jarrett@effortmark.co.uk
p. +44 (0)1525 370379

 


External link to another web site Associated Link:
Effortmark

other news

All change at the top for System Concepts
Source: System Concepts Ltd, 3 July 2009
 
Leslie Fountain has been promoted to joint Managing Director of leading usability consultancy System Concepts.

Life in UCD immortalised in fiction: you couldn't make it up
Source: UN, 2 July 2009
 
Sarah Herman's fictitious book on life in a user-centred design company has hit the shelves and The Guardian's book pages...

Interfaces Magazine - Issue 79: The Education Issue
Source: Interaction Group, 1 July 2009
 
The latest issue of Interfaces is now available as a free download from the Interaction Website.

Two new Behavioural research Tools from Noldus
Source: UN, 30 June 2009
 
Tool updates make on-site behavioural data collection easier.

Cell Phones that Listen and Learn
Source: MIT Technology Review, 29 June 2009
 
New software tracks a user's behavior by monitoring everyday sounds.

Top Six Don’ts for Usability Testing
Source: FutureNow Inc., 27 June 2009
 
Six tips for creating quality usability tests to ensure useful feedback from testers.

Usability: ‘Lovely software. But I can’t work it’
Source: FT.com, 26 June 2009
 
In a recent survey by Global Graphics, 77 per cent of office workers estimate they lose up to one hour a week because business software is difficult to use.

And what do you do?
Source: Dexo Design, 25 June 2009
 
How do you describe your job role? Here are the results of a recent 'Preferred UX/UI Title' Poll.

Most Doctors cite Usability as critical to Electronic Health Record Adoption
Source: TMCNet, 24 June 2009
 
It's all about 'meaningful use'.

Glossy monitors look good but can hurt
Source: QUT, 23 June 2009
 
A new advisory cites research which suggests high gloss monitors make users sit awkwardly.

 
 

 

home | contribute | subscribe | news feed/RSS | search | contact us | disclaimer

UsabilityNews.com (version 1.41), along with its associated web site and content,
are all strictly © Copyright of the BCS Interaction 2001-2009. All rights reserved.

Joanna Bawa (editor), Dave Clarke (founder, designer and developer). Ian Parry (graphics).