“Is acoustic lab testing really objective? If a company is paying for the test, don’t they just get the test results they want?”
Very reasonable questions. While some very competent, material testing can be informally conducted by a manufacturer’s own lab, no one outside of that company will give any credibility to such data. It’s not considered objective, obviously.
In general, objective data generally comes from a NVLAP certified acoustics laboratory. Someone has to pay the lab, and that’s generally the manufacturer of the product or perhaps an attorney involved with a lawsuit involving a product.
An independent lab lives or dies based on objectivity. Underwriters Laboratories is one example of these certified labs. Any given lab handles hundreds of tests annually. These tests get called into lawsuits all the time. Lack of objectivity means they lose all credibility, their certification is pulled and the lab is out of business. Someone may face jail time.
The labs themselves are closely governed by an oversight group, the NVLAP. The National Voluntary Laboratory Accreditation Program. A NVLAP certified lab must comply with a strict set of standards. Daily log of environmental conditions, maintenance logs of all equipment maintenance, calibrations, etc are all required to be on hand at all times. NVLAP will routinely inspect labs for compliance.
It is illegal to tamper with any test or test report. So falsifying data or rigging a test result will not NVLAP pull their certification, essentially shutting down the business, and someone could see jail time. It’s just not worth the risk and labs are very concerned and on alert.
Lastly, the test procedures themselves are highly scripted and defined by yet another governing body, the ASTM. The American Society for Testing and Materials ASTM Website .The ASTM describes exactly how every test will be conducted so that the results can be reproduced in another lab. There is an ASTM test standard for virtually everything, well beyond acoustics. If you wanted to have the shear strength of a bolt tested, there is an ASTM standard test for that. If you wanted to test an air conditioner, there is a standardized test for that as well.
In summary, an independent NVLAP certified test is completely objective.