AVS Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
7,043 Posts
Discussion Starter #1
I've noticed no Pro installer has posted objective charts of their clients home theater rooms final sound acoustic result.
Freq plots, ETC charts for above 250hz, waterfall charts for below 250hz, etc. Multiple seat positions, overlays, etc.
Why?
 

·
Registered
Joined
·
1,183 Posts
Because deep down our biological machine is trying to save a few calories for future famine, so we invent rationalizations for why we shouldn't bother. We do it with lots of things. It is called laziness. It strangely remains even after we realize that calories lost only mean we can eat more cake.
 

·
RETIRED theater builder
Joined
·
34,750 Posts
I can imagine that the guys charging large fees to do this work aren't anxious to a have a bunch of forum wankers criticize their work publically and posting data derived from whatever process and using less than pro measurement gear suggesting their rooms are better. I do recall some time back someone posted their own measurements of the pros work before and after.
 

·
Banned
Joined
·
29,681 Posts
Because deep down our biological machine is trying to save a few calories for future famine, so we invent rationalizations for why we shouldn't bother. We do it with lots of things. It is called laziness. It strangely remains even after we realize that calories lost only mean we can eat more cake.
Best post of the week ^
 

·
Banned
Joined
·
29,681 Posts
I can imagine that the guys charging large fees to do this work aren't anxious to a have a bunch of forum wankers criticize their work publically and posting data derived from whatever process and using less than pro measurement gear suggesting their rooms are better. I do recall some time back someone posted their own measurements of the pros work before and after.
I was thinking that except for the few top pro designers, most of the typical AV installers are chasing the $$$ more than the result. Your typical trunk slammer doesn't understand acoustic theory half as well as the OP does. They don't care half as much either.

I saw Mike ask this on FB and I thought to myself then the same as now. Most are either too lazy or too ignorant. The few that are neither of those things simply are smart enough no to do it.

When I think of a pro designer I think of Nyal or Dennis or Shawn. I think his question was more geared at the lower tier majority though. The more plentiful community of installers that rarely rise up to the enthusiast level.

The guys that are professionally certified and skilled don't want to waste thier time explaining or justify what they do to every Tom Dick and Harry with a forum boner. I don't blame them. The other 90% can't even figure out when they should use diffusion or abfusion instead of absorption. They get paid more to pull wires and program remotes.
 

·
Registered
Joined
·
3,768 Posts
Imagine you're the guy who has spent the last five years and a few thousand hours in training. You've got thousands of dollars tied up in gear and more in education. You appreciate that there are subtleties in an acoustic presentation that won't be quantified in an ETC plot and you know that most casual enthusiasts will not know what most of it is. The most that the average enthusiast (even avid AVS forum member) is going to *think* he understands is a frequency response plot - but even then, most of us would expect it to be flat. Even if the results are accompanied by careful objective descriptions and listening reports, the group of people interested is pretty small. And what does the calibrator/designer get from sharing? Well - he might get a couple referrals. He also might give a couple people the impression that all they have to do is make their graphs look like his, and they have recreated what he did. Of course that's not true in any meaningful realistic sense.

The customer for those guys' services doesn't have the time or interest in engineering his space, and showing us how it turned out doesn't do anything for almost anybody, really. There are a couple dozen individuals who are regulars here who might learn a lot from the sharing of those results - I like to think I'm one of them, and I'm sure Mike is as well, but the largest single effect of sharing that data is confusion, unfortunately.

What I think would be the most informative way to get that sort of information for serious enthusiasts is to take a couple weeks vacation and volunteer as an unpaid intern for a good calibrator. You could learn heaps in a week or two if you got to help with a few calibrations. That's not to say that I expect too many calibrators to line up to take on green help.
 

·
Registered
Joined
·
1,733 Posts
This thread is awesome, especially BIGs comments!!


I have put a few before / afters up, though mostly on my high end audio consulting work, not HT design. http://www.acousticfrontiers.com/category/blog/case-studies/


I have a few more case studies to add, including results from DLBecks Savoy and another forum member on here whose avatar I can't remember. I'm making it a point to get post measurements of all my projects.


But I will not be posting REW files, for the exact reason that others have indicated. There is stuff that people might think they understand and then look at my measurements and say it looks bad whereas to me it looks great.


Two major areas of disagreement would be importance of the T60 by frequency chart and the ETC chart. Some people, including well respected professional calibrators, think the T60 is all important. I very much think it is a secondary thing.\


There is also the case where the reader knows nothing about the constraints of the project, how much money was available to fix things, how much wall space there was, did the person want an all out assault or did they want something that looked nice, and all the other gazillion things that influence the final design.


Further in the range below 100Hz frequency response and spectral decay are more to do with how you have optimized your low frequencies (sub / listener / signal processing) rather than how you have acoustically treated your room. If the client only had budget or only wanted to use two subs then you are not going to have consistent response in all seats in a two row theater. Not possible. Would the educated know that yes. Would most forum dwellers know that...I don't think so.

Even a frequency response chart above the room mode region is open to interpretation. If you are in a small room with a lot of strong reflections you are going to see all kinds of bumps and dips due to phase cancellation (comb filtering). Realistically you do not hear those phase cancellations, you hear a superposition of all reflections. Phase and timing information gives your brain information about localization but your brain does not hear what the frequency response chart shows.


Hopefully Dragonflyr and cohorts are not reading this as they will be on this in an instant but ETCs are not really that valuable in my book. Sure they give you some arbitrary dB level but they do not tell you anything about spectral content of reflections or direct of reflections, two things which are extremely important to consider when you are evaluating the psychoacoustic effect of a reflection.
 
1 - 7 of 7 Posts
Top