Originally Posted by DanDan
So IMHO they are as or more significant than Lab results, in terms of practical small room acoustics at a prosumer level.
While I would agree that valid test results of DIY projects would benefit people greatly who were considering a DIY approach to their rooms, I would have to add the following.
Not looking to knock head here, but I am going to have to disagree. I know we've touched base on this before....... however I would be remiss if I didn't comment.
Product "A" is not guaranteed to produce the same results in each and every room it is installed in. Therefor the results of field testing (by anyone other than a certified person performing a tests within the requirements of a standard for such tests) is only meaningful to a small extent to that specific space.
It is meaningless in any other context.
This is due to a whole lot of factors - not the least of which is the level of isolation the space has from adjoining spaces/the outside world, but also room geometry, room finishes, room construction, etc.
So how does one compare 50 different company's products that were tested in 50 different spaces around the world to one another and arrive at any sort of meaningful determination of which one produces the best "bang for the buck"?
The most meaningful report is from products compared in spaces which should (at the very least) have the potential for producing meaning repeatable data.
So we have standards to design spaces (to perform tests in) that are meant to create conditions that (as nearly as is possible) are diffuse.
In this manner at least we have a chance at comparing products made all over the world to one another in a manner that allows us to make informed decisions in that regard.
BTW - just for the record - laboratory test rooms also have before tests performed on them - I would assume that data could be requested by the companies having tests performed at those spaces. I cannot see why this would be a problem.
This from ASTM C423:
6.2 It is advisable to make measurements in the room when it is empty and in the room when it contains the test specimen under conditions of temperature and relative humidity so nearly the same that the adjustments due to air absorption do not differ significantly.
That sould satisfy your need to see before/after instead of just the test results themselves.
Now, with all of that being said, as I have acknowledged in the past - I am not necessarily opposed to the though of in-situ testing - but if it is to be used in lieu of lab testing by a manufacturer
- it really does need to be performed by people certified to perform the tests - and in accordance with the applicable standards for that testing.
Note that the standards for field testing are pretty stringent and should produce meaningful results.
And then the product receives a test report certified by the company who performed the tests the same as if they had the tests done in a lab.
Personally I am not interested in, nor would I consider backing a product and recommending it's use if the only test data I could get on the product was in-situ testing that was done by the manufacturer themselves, or even by their clients........
There are a whole slew of things that can taint test results besides using incorrect methods of obtaining the data.