dewthedru Posted January 26, 2015 Author Share Posted January 26, 2015 Never mind. I thought 4 cubic feet would be 4x4x4. According to the DIY Sound Group page, the dimensions are 20"w x 23.5"h x 20.25" deep. Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 26, 2015 Share Posted January 26, 2015 (edited) Lol...a 4x4 enclosure for 20hz??? Wow! I don't know if I can swing selling that to my wife. Nevermind, you figured it out. Edited January 26, 2015 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
mattSER Posted January 26, 2015 Share Posted January 26, 2015 Never mind. I thought 4 cubic feet would be 4x4x4. According to the DIY Sound Group page, the dimensions are 20"w x 23.5"h x 20.25" deep. now that would be a monster sub Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 26, 2015 Share Posted January 26, 2015 (edited) Never mind. I thought 4 cubic feet would be 4x4x4. Multiply the internal dimensions to get the volume, not counting driver displacement and braces. 4x4x4 would be 64 cubic feet. 1x1x1 is 1 cubic foot, not 3. If using inches then divide the total by 1728. Edited January 26, 2015 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
Scrappydue Posted January 26, 2015 Share Posted January 26, 2015 Another excellent deal from Partsexpress, Dayton HO 18 plus a 4 cu ft Flat pack for $325 shipped: http://www.ebay.com/itm/Dayton-Audio-18-Reference-Series-HO-Subwoofer-and-Cabinet-P-300-7094-/221532177466?pt=LH_DefaultDomain_0&hash=item339458c43a I've thought about ordering a pair of these myself to replace the Ultra 2 subs I have. main problems with those are they are single voice coil. limits amp options a lot Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted January 26, 2015 Share Posted January 26, 2015 (edited) Here is a sim of the Ultimx 18 sealed Yellow and the SI Orange and my vented sub Red. The SI has more output above 40 Hz by around 2-3 db and the Ultimax seal has a hair more output below 40 Hz. The vented box has roughly a 12 db advantage at 16 - 20 Hz which is massive. Room size needs to always be considered in deciding betwee sealed or ported subs. For small room extension is good due to cabin gain and sealed subs are great. For large rooms, vented works best and go for the 15 Hz and up output due to low cabin gain. Edited January 26, 2015 by derrickdj1 Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 26, 2015 Share Posted January 26, 2015 (edited) Here is a sim of the Ultimx 18 sealed Yellow and the SI Orange and my vented sub Red. The SI has more output above 40 Hz by around 2-3 db and the Ultimax seal has a hair more output below 40 Hz. The vented box has roughly a 12 db advantage at 16 - 20 Hz which is massive. Room size needs to always be considered in deciding betwee sealed or ported subs. For small room extension is good due to cabin gain and sealed subs are great. For large rooms, vented works best and go for the 15 Hz and up output due to low cabin gain. Do you think tuning to 20 hz is good enough for home theater or does it really need to be tuned to 15? What did you model this at? Edited January 26, 2015 by MetropolisLakeOutfitters Quote Link to comment Share on other sites More sharing options...
Rowan611 Posted January 26, 2015 Share Posted January 26, 2015 Here is a sim of the Ultimx 18 sealed Yellow and the SI Orange and my vented sub Red. The SI has more output above 40 Hz by around 2-3 db and the Ultimax seal has a hair more output below 40 Hz. The vented box has roughly a 12 db advantage at 16 - 20 Hz which is massive. Room size needs to always be considered in deciding betwee sealed or ported subs. For small room extension is good due to cabin gain and sealed subs are great. For large rooms, vented works best and go for the 15 Hz and up output due to low cabin gain. Do you think tuning to 20 hz is good enough for home theater or does it really need to be tuned to 15? What did you model this at? Yes, at least 15. I love my THT, but wish it went to at least 15. But, it would have to be a lot bigger, and I would have to use a 18, just like a Ghorn. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 26, 2015 Share Posted January 26, 2015 Do you think tuning to 20 hz is good enough for home theater or does it really need to be tuned to 15? Room gain will get you lower. The cinema F-20 is a 20 Hz tapped horn and it does great for HT. The THT is tuned to 22Hz (I think) and people love it for HT. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 26, 2015 Share Posted January 26, 2015 There you go, I stand corrected. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 26, 2015 Share Posted January 26, 2015 (edited) Yes, at least 15. I love my THT, but wish it went to at least 15. But, it would have to be a lot bigger, and I would have to use a 18, just like a Ghorn. I'm in the middle of building a 17Hz tapped horn that only has a 28 1/2" x 25 3/8" footprint and uses a 15' 15Hz in room should not be a problem. It IS kind of tall though Edited January 26, 2015 by CECAA850 Quote Link to comment Share on other sites More sharing options...
Rowan611 Posted January 26, 2015 Share Posted January 26, 2015 Do you think tuning to 20 hz is good enough for home theater or does it really need to be tuned to 15? Room gain will get you lower. The cinema F-20 is a 20 Hz tapped horn and it does great for HT. The THT is tuned to 22Hz (I think) and people love it for HT. THT is a 20hz tune. I've never been able to measure mine, as I have no equipment to do so. But I do know MaxMercy got usable output on his down to 12hz in his room. He's a site admin on the data-bass forums (in case no one knows that name here). Quote Link to comment Share on other sites More sharing options...
Rowan611 Posted January 26, 2015 Share Posted January 26, 2015 Yes, at least 15. I love my THT, but wish it went to at least 15. But, it would have to be a lot bigger, and I would have to use a 18, just like a Ghorn. I'm in the middle of building a 17Hz tapped horn that only has a 28 1/2" x 25 3/8" footprint and uses a 15' 15Hz in room should not be a problem. It IS kind of tall though Did you design this yourself? I'd be curious to hear your impressions. I love horn subs. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 26, 2015 Share Posted January 26, 2015 The F-20 is a great bang for the buck sub and really not that hard to build, especially when you compare it to a THT. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 26, 2015 Share Posted January 26, 2015 Yes, at least 15. I love my THT, but wish it went to at least 15. But, it would have to be a lot bigger, and I would have to use a 18, just like a Ghorn. I'm in the middle of building a 17Hz tapped horn that only has a 28 1/2" x 25 3/8" footprint and uses a 15' 15Hz in room should not be a problem. It IS kind of tall though Did you design this yourself? I'd be curious to hear your impressions. I love horn subs. No, it's another one of Lil Mikes designs. I'm building it for a forum member out of Houston. Quote Link to comment Share on other sites More sharing options...
tromprof Posted January 26, 2015 Share Posted January 26, 2015 Do you think tuning to 20 hz is good enough for home theater or does it really need to be tuned to 15? Room gain will get you lower. The cinema F-20 is a 20 Hz tapped horn and it does great for HT. The THT is tuned to 22Hz (I think) and people love it for HT. My F-20s run out of steam at 17 HZ. Very strong at 20 HZ. Quote Link to comment Share on other sites More sharing options...
dewthedru Posted January 26, 2015 Author Share Posted January 26, 2015 Here is a sim of the Ultimx 18 sealed Yellow and the SI Orange and my vented sub Red. The SI has more output above 40 Hz by around 2-3 db and the Ultimax seal has a hair more output below 40 Hz. The vented box has roughly a 12 db advantage at 16 - 20 Hz which is massive. Room size needs to always be considered in deciding betwee sealed or ported subs. For small room extension is good due to cabin gain and sealed subs are great. For large rooms, vented works best and go for the 15 Hz and up output due to low cabin gain. Great. Another rabbit hole to go down! Read through this thread and am all excited about making a couple of these: http://www.avsforum.com/forum/155-diy-speakers-subs/1592098-diysoundgroup-s-stonehenge-build.html He used UXL-18s which are $550 each. Would the Ultimax 18s work about as well? would save me a few hundred $$. There is the possibility of an upcoming group buy on the UXL-18s which might help some with the price. If you answered my question in your graph above, I apologize. I don't really know how to interpret them. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted January 26, 2015 Share Posted January 26, 2015 (edited) The issue is not necessarily where the sub is tuned. Room size is a big factor. A subs tuned to 20 Hz can have a flat down to 10-15 Hz with no problem in smaller rooms with good room gain which is 12 db per octave for sealed subs. My subs are tune to around 20 Hz. Currently I can get flat to around 15 Hz in 5300 cu ft. using a HPF @ 20 Hz on the two vented subs. The system will do around 12 Hz flat if I close off part of the port on the vented sub. The 15 Hz and up makeup for any lack of extension. The vented subs 12 db advantage in the 15-20 Hz region is equal to adding 6 or 8 more sealed subs. Many people buy subs wanting the lowest extension which is not entirely correct. Most don't even know if their equipment chain will even support single digit extension. The bass system in the HT is the most difficult part compared to setting up and picking out speakers. Extension is good but on average you need 105-110 db at 10 or 12 for it to be meaningful. So, extension without force will not get you far. Also, in a movie even more demand is made since you are not just going for 110 db at 10 or 12 Hz and adding a lot of other frequencies in the mix and redirected bass. 95 + % of subs on the market can't hit the 122 db mark with redirecte bass if a movies call for it at the MLP. The ULX is a nice driver and depending on your room size, how many and what is the best alignment only you can decide. I personally don't want 8 or 16 subs in my HT room like some of the folks on AVS forum. Edited January 26, 2015 by derrickdj1 Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 26, 2015 Share Posted January 26, 2015 I personally don't want 8 or 16 subs in my HT room like some of the folks on AVS forum. I don't see the point when you can add a port and be better off with half the subs or less. I've often wondered how those big systems sound when turned down low. Can they even do low volume? I'm not sure. Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 26, 2015 Share Posted January 26, 2015 A subs tuned to 20 Hz can have a flat down to 10-15 Hz with no problem in smaller rooms with good room gain which is 12 db per octave for sealed subs. I never imagined that. I figured at 10 hz, a ported sub tuned to 20 would have the port's output 180 degrees out of phase with the driver. Quote Link to comment Share on other sites More sharing options...
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