twk123 Posted March 13, 2015 Share Posted March 13, 2015 Hey guys I watched an episode of TWIT- Home Theater Geeks today and that show always puts me into cracked out tweaker mode. Anyway, the episode was 178- Room Acoustics 102 and they spoke about how subwoofers should be placed in the corners of a theoretical room 75% the size of the actual room. I did my subwoofer crawl with my new Klipsch SW-12 and I ended up actually putting it 25% in from the front wall and the side which was a cool way of verifying theory with real life experience. However, rooms are 3D and I have only addressed the 2d modes of axial response which is clearly unacceptable for us perfectionist HT and music lovers. The sub is now on the floor and needs to be raised up to the proper 25%. That leaves me with the only realistic option of building a sub riser. We are renting as well and our floors are wood so I will want to isolate the sub too. I was thinking of keeping things simple and building a MDF box and filling it with sand for stability and dampening. Then maybe put closed cell foam between the sub and the stand and paint the whole thing with grey "Paint it stone". Has anyone here attempted anything similar with good results? I have heard good things on some of the other HT forums I lurk in. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted March 13, 2015 Share Posted March 13, 2015 For a subwoofer to affect vertical modes, a riser only needs to be roughly 2 ft. off the ground. The question before you do this is there a problem with vertical modes? Have you ran any test? Remember, the number of modes is constant for a given room volume. Also, stuffing the 2 ft. riser with acoustic material, not egg crat matress stuff, will act as a bass trap. Have you measured the bass decay in the room? I have all four subs on risers mainly for easy moving. The are around 4-6 in. off the ground. I kept it simple and brought 1/2 to 3/4 ply wood, cover them with outdoor capet and wheel on a couple of them. Quote Link to comment Share on other sites More sharing options...
twk123 Posted March 13, 2015 Author Share Posted March 13, 2015 For a subwoofer to affect vertical modes, a riser only needs to be roughly 2 ft. off the ground. The question before you do this is there a problem with vertical modes? Have you ran any test? Remember, the number of modes is constant for a given room volume. Also, stuffing the 2 ft. riser with acoustic material, not egg crat matress stuff, will act as a bass trap. Have you measured the bass decay in the room? I have all four subs on risers mainly for easy moving. The are around 4-6 in. off the ground. I kept it simple and brought 1/2 to 3/4 ply wood, cover them with outdoor capet and wheel on a couple of them. I have not ran any tests, this is based on anecdotal evidence of others. Do you know a good (Preferably free) software I can use to test the response? I do not have an Audessey enabled receiver but it would be good to actually quantify the results of room changes etc. I am pretty new to HT calibration and have generally winged it based on what I think sounds good so far. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted March 13, 2015 Share Posted March 13, 2015 (edited) REW(free) and a mic or Omnimic system will allow you to measure your system. REW is hard to learn than the Omnimic system. You will need a Mini DSP or sub amp with DSP and PEQ to tailor the room response. There is a learning curve to all of this stuff, lol. This will clean up the sound more than a riser and should be part of setting up a HT. Auddysee does a pretty good job for many people. Edited March 13, 2015 by derrickdj1 Quote Link to comment Share on other sites More sharing options...
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