You need to provide a lot more information for an answer. Are you trying to contain the noise? or keep it out? Does the tester generate significant vibration which is transmitted to the floor? What is the sound level of the tester? What do you want it reduced to? What are the sound levels in each octave band frequency?<br><br>Most enclosure ads are for companies trying to sell you an enclosure, they won't be too helpful in giving you the plans. If you want to build one, I may be able to help if you provide the above information, but please note that a successful enclosure is in the details. Anyone can build a box which may or may not be satisfactory, but it takes skill and experience to build a high performance sound enclosure.<br><br>If you don't have the above information, then ball park it. Is the noise high or low frequency? Is it impulsive (sharp, short duration) noise, or is it continuous?<br><br>Sorry for all the questions, but its the only way.