Acoustilog sells no products. That makes us independent consultants. We make no extra profit from an expensive job or by selling any particular brand of materials.
Our interest the same as yours: the most efficient and effective design.
There is however another type of "consultant", one that either represents certain brands of products or perhaps even manufactures their own line. We think this sort of business is more accurately called "sales", rather than "consultation".
Proper soundproofing involves techniques more often than special materials. But you can't expect a salesman to recommend products he doesn't sell, and these salespeople do not sell the common, inexpensive building materials that are often the best choice. You especially can't expect them to recommend measures that involve no "materials" at all, like machine repairs or sound-system modifications.
Some of these "Salesperson/Consultants" don't even make any acoustic tests or detailed inspections. Some offer their "advice" over the phone! Be advised: No one can design an effective and efficient solution without diagnosing the problem first.
Expertise and proper measurements can save time, trouble and money.
Read "A Case Study in Two Letters": A cautionary tale of a job done twice and a lawsuit as told in two letters of thanks from a client (finally) enjoying some quiet.
In another twist on "sales-consultation", we have recently heard of companies offering “Remote Sound Testing”; they send you a sound measuring device to allow them to “consult” without coming to you. They then offer solutions, featuring - not surprisingly - products they sell themselves. One company offers a credit for their multi-thousand dollar report, but read the fine print: it only applies to a purchase of at least $10,000 of their materials.
Anyone who claims that such a device can replace the need for an independent acoustic consultant is doing you a serious disservice. They have neither the infomation nor the independent perspective needed to make the proper recommendations.
By carefully investigating in person, I frequently find simple ways to solve problems. But I have to inspect under, over, around, in-between and inside of hidden cavities. They ask you to send a few pictures, none of which will show the compressor unit in the floor above with the faulty mounting.
I use a stethoscope, an accelerometer, a spectrum analyzer and my ears to track down the noise as I move around the room and adjoining spaces. They ask you to put their gadget in a handful of predetermined locations.
I calibrate my equipment at every job; Their gadget certainly will not be.
They sell a particular line of products; I can recommend the most efficient solution, whoever might sell it. That might new bearings for the fan motor rather than an "acoustic" material. Or it might be Sheetrock. Sound isolation is more about techniques than specific "special" materials.
One of these services claims to be “guaranteed”, but their literature says that they “can not control whether or not the end result will be well received”.
These types of errors make it clear that anyone who offers such a remote consulting service does not have the experience to properly "consult" for you.