room treatment effectiveness

2chnlben:

However, my audio dealer friend (whom I have great respect for) has informed me that, unless the traps are EXTREMELY large, they will have no effect on the lowest frequencies, which are, in my case, the frequencies that are causing the problem.

Exactly what frequency range are you having trouble with?

ASC tube traps(.pdf) offer full wave bandwidth absorption down to:
9” 110Hz
11” 90Hz
13” 70Hz
16” 55Hz
20” 30Hz

Their fractional tube traps(1/4 & 1/2) take up even less room and can provide full bandwidth absorption down to 55Hz. The quarter rounds are perfect for corners.

Darkmoebius:
Until my friend measures the room this weekend, I won't know the exact range(s). We both believe that the problem is near the 30-36Hz range. I did not have the same problem with my previous speakers that only went to 38Hz. My current speakers go below that down to 28Hz. I believe what my friend has tried to explain to me is that although a given product/material may be rated at absorbing a specific lower range of frequencies (i.e.: the 20" ASC Tube Trap), in order to effectively treat a given room, one would need specific quantities of that given material/product, and according to my friend, I would need more of that particular material/product than would fit reasonably into my room.

2chnben: You understand the problem well. Not only does the size increase as the frequency decreases and I do not agree with the diameters that the ASC describe--they need to be significantly larger. But the size increase AND the efficiency decreases. As the frequency gets lower, the problem gets tougher. Now 200 Hz is not that tough--that can be dealt with passively in most (not all) situations, unless there are some other serious restrictions (like no corners or space to work in). Usually the really problematic issues are 100 hz and lower.

I am fairly late in responding to this thread but here goes.

Before I spend money on room treatment, I would like to hear of positve/negative experiences and whether the results are objectively measurable or merely subjective.

We often hear that the room constitutes to about 50% to the sound apart from the equipment and speakers, and I totally agree with this statement. I've recently made a huge discovery in moving 4 pieces of RPG omnifussors to the front wall(behind the speakers). They were previously at the rear wall. Since I have a projector screen at the front wall, I can only squeeze in the diffusor panels at the side of the screen just behind the speakers. To my surprise, the sound suddenly takes on a realism so startling it's amazing. The struck of cymbals and percussion sound so real it's spooky. The sound is like coming from the side walls rather than from the speakers. Also, the highs are suddenly less piercing and it's wonderful to be able to crank up the volume higher without feeling any discomfort or strain on the ears. The differences are noticeable and you don't need "golden" ears to hear them. I don't need to strain my ears to perceive the differences unlike with cables and tweaks. My gut feeling tells me I will obtain greater improvements if I were to place another 2 pieces of omnifussors at the middle of the front wall. Unfortunately I can't do that since they will block the projector screen.

I have experimented quite a lot in my dedicated room and I now have absorption panels at both side and rear walls with some diffusion at the front wall. I have taken a look at your room and you do have a great system based around the N802. I guess placing treatments at the front portion(behind the speakers) is out since it's the doorway. In that sense I suppose you may be compromised at what you can achieve to improve your room acoustics. But one thing is for sure, room treatments have made a positive impact in my system as it would to any system. The question that remains is what treatment to get. From the way I see it, there are only two ways you can go about it which is either to buy and experiment yourself, or hire Rives services. :)

Now I need to figure out what to do next with the ceiling .........

For the listening room there is one rule: It should have good acoustic properties from the very beginning so you could optimize it with acoustic devices. If the room is bad, then you are in big trouble. There is no acoustic device that can turn your room into a good sounding one. Of course you can improve it somewhat but you'll need physically LARGE devices to overcome the problems, especially bass related problems.

Chris