damonrpayne Posted August 10, 2004 Share Posted August 10, 2004 I keep finding different golden mean ratios for rooms on the web! 18'x20' is a good room, what would be one step up (just slightly larger) room size but still be accousticly good. I know 19' is a dimension to avoid, so like 20'x23' ? Quote Link to comment Share on other sites More sharing options...
artto Posted August 10, 2004 Share Posted August 10, 2004 We need the height dimension. Quote Link to comment Share on other sites More sharing options...
damonrpayne Posted August 10, 2004 Author Share Posted August 10, 2004 Of course, 8 feet. It may work out to be slightly taller but let's use 8 feet. The "largest" ratio I have found is a width of 1.60xceiling height and length of 2.33ceiling height. This only goes up to 12 feet wide with an eight foot ceiling. Is there a more generic formula I can use or must I search for these tables of ratios? I did order "master handbook of acoustics" as well. Quote Link to comment Share on other sites More sharing options...
Olorin Posted August 10, 2004 Share Posted August 10, 2004 I was looking into this just yesterday, and on this page -- http://www.electroacoustics.co.uk/article/essroom.htm -- I found this statement: "The maths is too complicated to go into here, but if the ratios of height to width to length (in any order) are 1.14:1.39:1 or 1.28:1.54:1 or 1.60:2.33:1 (Sepmeyer's Golden Ratios, often attributed incorrectly to Bolt), then the modes will be perfectly spaced, and LF response is pretty much guaranteed to be smooth." Somebody with more knowledge than I have will have to comment on the truth or fiction of it. Quote Link to comment Share on other sites More sharing options...
damonrpayne Posted August 10, 2004 Author Share Posted August 10, 2004 "The maths is too complicated", I hope their knowledge of acoustics is better than their grammar. I don't know enough yet to properly interpret the room modes calculator I have, but by eyeballing the spreadsheet there seems to be about as many modes at 20x23 as at 18x20. Quote Link to comment Share on other sites More sharing options...
Olorin Posted August 10, 2004 Share Posted August 10, 2004 Euro-English uses maths for mathematics, so that's standard and proper for that side of the pond, but "maths" is still plural, so you'd look for the plural verb as well. Books and covers just the same. Do any of the alternative ratios look good for room and your calculator? Just curious, really -- I'm a long way from even starting on my room. Quote Link to comment Share on other sites More sharing options...
artto Posted August 10, 2004 Share Posted August 10, 2004 First of all. the "Golden Mean" ratios are simply a guideline. There are rooms that fall outside of "the curve" that sound fine. The more you fall outside of the curve, the more likely you are to have low frequency response anomolies. 18x20x8= 50modes with a spacing of 1.8Hz 20x23x8= 62modes with a spacing of 1.4Hz the second one is better. The second one is also better using the 'half-room principal' on the ceiling (whereby the ceiling dimension of 16' is used, 8'=1/2 of 16) there will be other advantages to the 20x23 room as well. go with it if you can. Quote Link to comment Share on other sites More sharing options...
artto Posted August 10, 2004 Share Posted August 10, 2004 ---------------- On 8/10/2004 4:02:23 PM Olorin wrote: I was looking into this just yesterday, and on this page -- http://www.electroacoustics.co.uk/article/essroom.htm -- I found this statement: "The maths is too complicated to go into here, but if the ratios of height to width to length (in any order) are 1.14:1.39:1 or 1.28:1.54:1 or 1.60:2.33:1 (Sepmeyer's Golden Ratios, often attributed incorrectly to Bolt), then the modes will be perfectly spaced, and LF response is pretty much guaranteed to be smooth." Somebody with more knowledge than I have will have to comment on the truth or fiction of it. ---------------- The range specified by Bolt is 1:1.26:1.59, to, 1:1.5:2.5. There are others of course. There is more than one to "skin the cat". There is a european standard as well: Acceptable room if: 1.1*(W/H) < (L/H) < 4.5*(W/H)-4 1.2 1.3 1.1 The main idea is to have as many evenly spaced modes as possible. The more modes the better. The closer the distribution (eveness) the better. In fact, after the room size gets large enough, to the point where any of the room's dimensions are longer than the longest wavelengths of the lowest frequencies to be produced, modes are no longer much of a concern. 16Hz=aprx 70.5 feet Quote Link to comment Share on other sites More sharing options...
Klipschfoot Posted August 11, 2004 Share Posted August 11, 2004 Just how technical do you want to get? (Beware that it is a PDF so it may be slow-go on dialup.) Quote Link to comment Share on other sites More sharing options...
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