Originally Posted by cannga
Hi I am trying to learn RC processes and becoming ever more confused.
My posts have a way of doing that sometimes
I think Dan mentioned he had to remove the theater chairs the other day for some process to work (??), and you need a pro tuning the system, not an automated process (??), and now this. If true, I think a lot of people like me ("audiophiles" with open mind) are just going to get scared from buying anything.
Well, all the products being talked about are professionally installed ones. But this is not an all or nothing case. For example, we through JBL provide full turnkey optimization of subwoofer placement. Here is a bit on it from the presentation:
As the slide says, all we need is the room dimensions, possible locations of the subs and the number you will tolerate. We then come back with the subs and the nice simulations I showed earlier that tells you how smooth the response will be.
I can't speak about the systems Dan has tested but the JBL Synthesis is very automated and most of the time the single path through it does the job. No knowledge of acoustics is needed to do that although the process does require a dealer measurement kit. The same technology however will become available next year in the Lexicon MP-20 and that will be something users can do on their own.
1. Are you saying that if my speakers don't have the "correct" power response, then none of these processes - whether Trinnov, or Dirac, or JBL, will work?
The process works. But it cannot fix certain problems such as those caused by the power response of the speakers. Those defects remain. And you have to make sure to listen to the system to make sure it did not attempt to "fix" those issues. This is why sometimes people think they get worse sound with room eq than without.
My speakers are Thiel CS5i, and Thiel MCS center, how do I know if they have the appropriate power responses, that are correctable? What is an appropriate power response?
You are asking something that requires a full chapter in a book to explain
. But it is an excellent question. Dr. Toole's books cover this in great detail.
Short answer is that you probably don't know if your speakers have poor power response and no way of getting such data. Harman measures this using a special jig that measures 70 points in 3-D space, determining the sum total response of the speaker. Most other speaker companies don't perform these measurements and optimizing their speaker sound using other means.
2. Reading your post, it seems the JBL process is excellent, but is tuned with JBL speakers and hence work with JBL speakers only?
No, it works with any speakers from Harman group including Revel and of course JBL. As I noted though, it can be told that you have a third-party speaker and then it will do its best. There is then some variability there as it won't be as good as it knowing the speaker response precisely.
3. What's the point of room correction if you require 8 (or however many) subs for it to work? You are selecting out 0.05% of customers if this is true, no? This doesn't sound like room correction, but more like using electronics to determine how many more speakers to add to your room?
I didn't mention needing 8 subs. But the more you can have, the more degrees of freedom for the optimization analysis to find optimal placement so that your room has the best response without any EQ. You are often better off buying 4 cheaper subs this way, than one big expensive one.
You are right that very few people use multiple subs. My point is that we need to fix that, before we fix anything else such as applying EQ. Invest the money up front in more subs. And don't think subs need to be on the floor always. For example, in our reference theater
we have subs in the ceiling and on the side walls. All hidden from view. Simulations can be done on variable number and you can choose the best set. For example, if you can do three subs comfortably but four painfully, the simulation can tell you that before you even purchase a sub! You can then make the call as to whether the improvement is worth it or not. In the case of the one simulation I showed, we deployed three. We are looking at 6 subs for our next system.
As an interesting aside, the optimization for the 3-sub configuration tried nearly 40,000 potential locations for the subs and recommended the best one which we used. No way can you do that manually.
4. Did I understand correctly that some of these processes require a pro to listen? That sounds quite subjective and wouldn't that mean the sound you have depends on who is tuning your system? Whatever it is, that doesn't sound like room correction, which I thought was an objecive process - perhaps I misunderstood this whole thing?
I can't speak for the others but in case of JBL Synthesis, no, you don't need to be a pro. The only thing we typical adjust are the level of bass as sometimes it is too high causing the sub to clip, sometimes a bit low. It is usually a few minute adjustment. This is with an all JBL system. With other speakers, it may take more work.
The question in the context of these devices are moot in that they are only sold through the pro channel anyway. The Lexicon will be the exception when it comes out with this class performance.
Did I make you more concerned or less?