Professional Acoustic Treatment

[djeickme]

I thought I would share my experience with getting a professional acoustician to design my home theatre room.

I am renovating a 115 year old church into a house. On the lower level I have put in a purpose built home theatre room. Nothing huge (about 12X14'6" with sloped 10'6 to 10' ceilings) but still a pretty big endeavour in my book, so I decided to get professional help. I have been dealing with the people at Acoustic Sciences. I looked into a variety of services before choosing Acoustic Sciences. I liked them because they were an all in one outfit. They could do the acoustic design and provide all the products required. While I realize that this limits you to there product, they are well respected products and I did not want to have to run around looking for acoustic treatments on my own after getting the plan.

Unfortunately, the room dimensions were already set by the time they became involved but they were able to help guide me on construction techniques. There was no space for staggered studs so we went with resiliant channels. These made my contractor crazy. It is not that they are particularly challenging but they are very time consuming. Combine that with the necessity of two layers of sheet rock with dampening between them resulted in a half day job growing into a day and a half job. I thought about DIY but it probably would have taken me a month given the amount of time it took him. I must say that there has been a change in the acoustic since the sheet rock is finished. I expected a "deader" sound but in fact the sound is more lively, if you have ever been to a purpose built opera house you will know what I mean. There is no way to be quiet as every sound is clearly projected. It is not really reverberant, just every sound is clearly there.

The biggest challenge was communicating with the acoustician. We had already had a parting of the ways with out architect on the project (as well as an interior designer and a general contractor) , so we didn't have professionally done measured drawings. While I did up some quick CAD drawings it was still very hard to communicate the construction details to the acoustician (now that is at least in part due to some of the unusual construction methods due to the historic nature of the property). I would advise trying to get the acoustician to do a site visit. What took months of email and phone conversations, could have been done in two hours if we had done it in person. The other is start early. We ended up with a significant construction delay because of the time it took to finalize the acoustics which just led to frustration for all concerned.

The next odyssey is the in room acoustic treatments. I will keep the forum posted and perhaps post some pictures of the room once I find my digital camera again. After that I get to think about how to treat the "listening room" which is also the kitchen, living room, dinning room, den and office as it is part of a 35 000 cubic foot room that used to be the church sanctuary. That should be an interesting challenge.

Dan

[atledreier]

Good luck! Sounds like quite a challenge. Will be awesome when you pull it off, though!

[mas]

A couple of questions and a few thoughts - pardon me if I have missed a few points...

...Trouble communicating with the acoustician...Hmmm.

Am I to assume that he is not coming on site and making measurements with a TEF or EASERA, etc.???? A BIG red flag!


May I suggest that if he is not, he is simply doing basic ray tracing and napkin analysis.

Neither will he have ETCs, etc. by which to provide guidelines for treatment and nor a standard by which to ascertain the effectiveness of the proposed treatments and to provide a verifiable proof of performance of the resultant system.

In other words, you will simply have a 'different' sounding room! ...Not necessarily an optimally sounding room! I would be hesitant to pay for such a service.

There are far too many qualified folks who would be glad to provide measurements utilizing the TEF or EASRA and to offer a verifiable before and after response guideline along with follow up tweaking and proof of performance.

[djeickme]

Ideally an in room consultation would be best but for the vast majority of people on this forum and in general that is not really an option. If you are located outside a major city, it is all but impossible to find an acoustic engineer that will perform an on-site analysis for anything approaching a reasonable amount of money. Heck I am located in Canada and I couldn't even find a single acoustician listed as operating in Canada. I am sure that there are some companies that are providing this service in Toronto, Montreal and Vancouver but there is no simple reliable way to find them. If I wanted to pay for two days travel time, plus travel expenses and accomodation, on top of the consulting fee, I could get an in room measurement but I wouldn't have any money left over to actually treat the room (and this is based on a budget for acoustics of about $10 000). I agree that the finest results would come from an in room consultation to tweak things both by ear and by measurement, but I think (and there are many published reviews to back this up as well as it being the standard operating practice for many well respected acoustic treatment companies like Acoustic Sciences and Rives) that a mathematical model of the room based on sound basic acoustic principles can get you 80-90% of the results of the in room consultation with a lot less hassle.

[mas]

djeickme wrote:

Ideally an in room consultation would be best but for the vast majority of people on this forum and in general that is not really an option. If you are located outside a major city, it is all but impossible to find an acoustic engineer that will perform an on-site analysis for anything approaching a reasonable amount of money. Heck I am located in Canada and I couldn't even find a single acoustician listed as operating in Canada. I am sure that there are some companies that are providing this service in Toronto, Montreal and Vancouver but there is no simple reliable way to find them. If I wanted to pay for two days travel time, plus travel expenses and accomodation, on top of the consulting fee, I could get an in room measurement but I wouldn't have any money left over to actually treat the room (and this is based on a budget for acoustics of about $10 000). I agree that the finest results would come from an in room consultation to tweak things both by ear and by measurement, but I think (and there are many published reviews to back this up as well as it being the standard operating practice for many well respected acoustic treatment companies like Acoustic Sciences and Rives) that a mathematical model of the room based on sound basic acoustic principles can get you 80-90% of the results of the in room consultation with a lot less hassle.

I would suggest contacting Synergetic Audio Concepts (SynAudCon www.synaudcon.com/ ) and requesting a listing of participants located in your area. Not all will necessarily have a TEF or EASRA, but the odds of finding someone with access to one is great - as well as finding someone willing to do the job for a very reasonable fee - be it for the analysis, recommendation for treatment, or a full turnkey project.

As far as what others are offering via the web, i would check a bit further into the actual tools.

When we encounter limitations regarding the use of such modeling tools as EASE and CATT-A for small rooms, I suggest that what you are indeed receiving by mail based upon your room drawing is little more than an exercise in cursory ray tracing and at best a modal analysis that is ONLY accurate for a mathematically ideal rectangular enclosure - both of which any person here can easily do.

While they can give you a general direction - I defy them to provide a performance guarantee for anything other than an overdamped room.

Now of course theirs comes with a list of suggested products that they will conveniently sell you.

Now don't get me wrong, I am not denigrating anyone simply because they sell product, but the analysis can be done more cheaply than you suspect once you locate a practitioner with the right tools. But I do become a bit frustrated at listening to so many who have not done so telling us how it is not reasonable. I will admit that it is a bit difficult to source those with the necessary skills and tools - especially when so many sources that folks use here lack such experience and equipment - but they are around and often very happy to take a few hours one afternoon and help someone out in a very equitable arrangement.

And you just might discover that those who have gone to the trouble to seek out additional training and to make the investment in state of the art tools are also personally eager to help others as well - as why else would someone go to such trouble and expense - especially when the scuttlebutt is that they either do not exist, or that you don't need them at all when there are websites that promise to analyze your room based upon a freehand drawing on a napkin!