Can you correct nulls with acoustic treatments.
You have to understand the nature of nulls, meaning that a null is a depression in frequency response due to cancellation effects based on room interaction. A null can not be tuned out by passive attenuation which is what room treatments can accomplish. You must redirect the energy by repositioning or by adding more bass energy to compensate for the null. |
Thats the whole idea. Well part of it anyway. To reduce standing waves (peaks and nulls), along with modal ringing, which is just as important. To absorb or diffuse sound in the room to avoid ringing and flutter echoes, and improve stereo imaging. This is some of the things that acoustic treatment helps with and which EQ cannot. Now about those acoustic resonators.... Bob |
Hi Jim, Welcome to the wonderful world of measurements. Its seems to me that you have two basic choices. 1. Move your speakers and listening position about until you get the best subjective results and then stop. Trust me, few do better. 2. Get serious about measuring and the post your results so others can coach you through the process of taking measurements and interpreting them. Expect a serious learning curve. You may eventually opt for room correction, but you should be properly informed before spending. New speakers may be far cheaper - or may do nothing to correct the problem. I went for a Tact unit and a sub with my dipoles. I am happy with the results, but it took a while. regards, Sam |
Speaker and/or listener placement along with capacitive style low frequency traps can help. The first thing is to figure out why you have the nulls. Are they uniform around the room (a suckout), are they caused by a piece of furniture (I've gotten my share of surprises here), or are they a basic function of room dimensions. I won't go into great detail for any of these, but rule out furniture first--remove anything that might be causing the problem and remeasure. Second is to map the room with your problem freuqencies--do they vary relative to the wavelength of that frequency? If so, it's a basic room mode issue. Placement can be a big help here as can the traps. Now one thing you need to be aware of is there will always be one frequency at the centerline of the room that will be peaked, and another nulled. There is very little you can do about this with parallel walls. Calculate F1 and F2 for the width and that will tell you what those frequencies will be (this assumes you sit at the centerline of the room as most people do--while it has modal issues it typically has the best imaging). Now if there are other freuqencies you can see if you have an 1/4 wavelength cancellations. Are the speakers 1/4 of a wavelength off a boundary of that frequency? If so, they are cancelling that frequency out to some degree and should be moved to a distance that helps balance other peaked modes. Sounds easy--but it's a little more daunting because you'll find you will fix problem A reduce problem B and create a new set of problems. Here is a link which may be of more help on this issue. Rives Audio Listening room tutorial. There are also some good software programs such as Cara and RPG room optimizer that can help you as well. |
