how do professionals do sub-placement?

Hello everyone,

I have been out and about travelling and I haven't read the latest postings in about 3 weeks!!! I shall get to that as soon as I make this post. As I was sitting in the airport terminal dreaming of my soon-to-be Axiom system I was struck by a thought....it has been suggested that one of the best ways to find out where to place your sub is perform the crawl test, correct? My question is how do professional HT technicians figure out where to place the sub in the specific room, do they also perform the crawl test, years of experience, I don't know. thanks for all your responses!!

Jason

I have been told that most of them ask where you want the sub, hook it up and say "dang, doesn't that bass sound great ?" and then leave quickly

Seriously, the very best ones (eg. Rives) design the room around speaker placement and seating location so usually not much tweaking is required, but I think the first explanation is closer for most of the "pros".

My brother in law talked to a number of supposed HT experts about systems and sub placement -- I don't think he got good advice from even one.

http://www.velodyne.com/velodyne/products/product.aspx?ID=15&sid=842j977i

i would think somthing like this.. i think tharkun (sp?) has one, a few others do as well i think...

That would definitely help (as would a BFD) but you pretty much have to leave the SMS-1 or BFD at the customer site, ie customer buys it, pro hooks it up and pushed a couple of buttons, customer thinks "geez, I could do that"

Oddly enough, not a single installer we talked to even hinted at using any kind of measuring equipment, either for simple frequency response plots or most sophisticated decay & echo analysis.

With the real acoustical engineering firms it's a different story, of course.

FWIW:

Leaving the SMS-1 at the site would provide room EQ for the sub, but it can help with placement during setup, without being left as part of the install.

Since the SMS puts a graph on the TV of your response at the microphone, you can try different placements and phase settings to find the smoothest response. This is all done (and recommended) before any EQ is applied to maximize the system.

The other approach is to put the sub at the primary listening position and move the mic around the room to find the best spot. This is similar to the crawl test, but you don't have to crawl, just hold the mic near ear level.