derrickdj1 Posted February 13, 2015 Share Posted February 13, 2015 Nothing like 4 subs for a good room FR. I got the Omnimic to measure but, there was not a lot to do with the FR. Quote Link to comment Share on other sites More sharing options...
wvu80 Posted February 13, 2015 Share Posted February 13, 2015 I say screw the WAF and have 4 big subs! Problem solved. Pick one. Quote Link to comment Share on other sites More sharing options...
Scrappydue Posted February 13, 2015 Share Posted February 13, 2015 I say screw the WAF and have 4 big subs! Problem solved. Pick one. both 1 Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted February 13, 2015 Share Posted February 13, 2015 Every time Dave whips out the science I have to read his post about 5 times. 2 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted February 13, 2015 Share Posted February 13, 2015 Every time Dave whips out the science I have to read his post about 5 times. You too? 2 Quote Link to comment Share on other sites More sharing options...
Jay L Posted February 14, 2015 Share Posted February 14, 2015 Every time Dave whips out the science I have to read his post about 5 times. You too? So do others at work. 2 Quote Link to comment Share on other sites More sharing options...
The Dude Posted February 14, 2015 Share Posted February 14, 2015 Every time Dave whips out the science I have to read his post about 5 times. Don't feel bad, I can't even read it once . 1 Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted February 14, 2015 Share Posted February 14, 2015 With the efficiency of LaScalas those little cubes could never keep up. That's my current situation. In our old place, my half-width THT managed a couple dB SPL over 115 from 16Hz on up, which was a great match for two La Scala in a phantom center arrangement and just the right EQ. With four more cabs (the pair of HIP and a close-coupled pair of La Scala for the center), and in the absence of EQ, it's simply no contest against the sub. It's back to needing more to keep up when the volume gets stupid. Especially with that center pair....man, they really pack a wallop! 1 Quote Link to comment Share on other sites More sharing options...
artto Posted February 14, 2015 Share Posted February 14, 2015 (edited) I'd like to contribute some of my experience as a bass player to shed some light. BTW, I like Dave's explanation. Fs is indeed a major part of the equation and a major reason why many of us don't perceive the smaller driver "woofers" or subwoofers to sound as deep or as powerful. Since the mid 90's I've used a sort of modular bass rig. I have several different sizes of cabinets with different size drivers & number of drivers. The "standard" big rig is generally a 1x15, 4x10, & and a 4x5. I've tried two 4x10 and two 2x10 stacked vertically like a line source. The smaller 10" drivers never project (throw) the sound as far as the larger drivers. The smaller 10" driver cabinets may measure the same low-end frequency response but they don't sound as "heavy" or produce as much "weight" (although they're physically much heavier). A number of times in a smaller club I tried two 2x10 stacked vertically to see if the line source did a better job of throwing the sound farther back but it didn't, especially at lower frequencies. I've also used an SWR 8x8 (Henry the Eighth as the manufacturer called it) bass cabinet. It sounded great. However it too could not throw the low frequencies to the back of the room even though it has more surface area than a 2x15 and had a very weighty sound up close. My conclusion is that the smaller bass drivers are fine as monitors, used up close you can hear the detail better without overwhelming the audience or neighbors as the case may be, but if you want and need the power & feel on the low-end the the larger diameter drivers tend to do a better job. In my dedicated home dedicated listening room I'm using four Epik Empire (2x15 each), two in the back corners and one each under the SH50 as pedestals about 6 feet from the front wall, 2 feet from the sides. On the loudest program material (Telarc 1812 cannon shots, The Gates of Dafos, Insane Clown Posse) played louder than I would normally listen to it, you can barely see the diaphragms move. The resulting low frequency output produces an extremely low WAF. Edited February 14, 2015 by artto 1 Quote Link to comment Share on other sites More sharing options...
eth2 Posted February 14, 2015 Share Posted February 14, 2015 To what degree does the dipole nature of a TH enclosure increase the "surface area?" I also understand that the benefits of multiple smaller subs can offset...Is there a simple formula? I suppose sophisticated programs like Horn Response or Akabak take all of the foregoing into consideration. Also note that using a multiplicity subs, either scattered around the room or with mouths manifolded together all in one location in the room, generally obeys the 3 dB nearfield increase per doubling of driver total driven projected area (in the direction of the axial driver motion). In general, one doesn't count the surround areas of the drivers in these calculations. If you manifold multiple subs' mouths together, you will see a smoothing and deepening of the FR in-room at the locations where bass is not cancelled by room modes. If you scatter the subs out in the room along the walls, corners, or floor, you will see less in-room cancellation response at your listening position but you won't get the beneficial effects of FR extension and smoothing from manifolding together. If you have access to Hornresp or AkaBak, I'd think that you can generally answer your own questions without my diatribe above (...sorry that I used a scatter-gun approach to answer your questions, since I really don't know what you are doing...) simply by choosing several examples and modeling them, which will give more accurate predictions. Hornresp does room corner, wall located, or half space (out on the floor) single loudspeaker (or subwoofer) calculations, but I haven't seen a direct capability to manifold multiple subwoofer mouths together. There are other programs available to estimate room response, the easiest of which I've found to use is Room EQ Wizard (REW), with its enhanced ability to place more than one sub in room at various locations and "walk around" the microphone positions to see the normalized FR/room null plot change immediately to the right of the interactive room geometry plot. I assume that you want to cover an area of the room, usually at your listening positions, with low bass, i.e., well below the so-called transition frequency (Schroeder frequency) of the room. Using REW's room simulator is the best and easiest way that I've seen to visualize that. Chris Every time I think I know what is going on, Chris demonstrates to me that I don't have a clue. Quote Link to comment Share on other sites More sharing options...
DizRotus Posted February 14, 2015 Author Share Posted February 14, 2015 (edited) artto, on 14 Feb 2015 - 1:54 PM, said: My conclusion is that the smaller bass drivers are fine as monitors, used up close you can hear the detail better without overwhelming the audience or neighbors as the case may be, but if you want and need the power & feel on the low-end the the larger diameter drivers tend to do a better job. Chris A, on 26 Jan 2015 - 05:40 AM, said: There are other programs available to estimate room response, the easiest of which I've found to use is Room EQ Wizard (REW), with its enhanced ability to place more than one sub in room at various locations and "walk around" the microphone positions to see the normalized FR/room null plot change immediately to the right of the interactive room geometry plot. I assume that you want to cover an area of the room, usually at your listening positions, with low bass, i.e., well below the so-called transition frequency (Schroeder frequency) of the room. Using REW's room simulator is the best and easiest way that I've seen to visualize that. As you can see, my small space is clearly "near-field." Compared to artto's magnificent space, it's like being inside a giant pair of headphones. The four Exodus Anarchy tapped horn subs sound great with all four driven by a single Dayton 240. This weekend I hope to put my iNuke 1000dsp into service. Eventually, with the help of Brett, aka bhenry, and Glenn, aka Picky, I hope to dial in the small space with REW and other tools. One thing I don't uderstand about tapped horns (there's many things I also don't understand) pertains to distortion. The ideal drivers have a large xmas, i.e., they can move relatively large amounts of air for their diameter. I've heard it said that tapped horns have low distortion, due to small excursions. That seems to contradict the need for a large xmas. The bottom line is these four 25 Hz TH subs produce deep natural bass with plenty of SPL for the small space. You don't hear the subs. You don't perceive the subs as a source of sound. Edited February 14, 2015 by DizRotus Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted February 14, 2015 Share Posted February 14, 2015 (edited) Neil, you should get great cabinet gain in a smaller room. You should be in bass heaven, lol. A horn magifies the sound which is why klipsch are more efficient than most speakers. Anytime this magification happens, less power for the same spl. and less cone movement and less distortion. C/2*L: subwoofer Room Gain formula Speed of sound 1130 ft per sec L: length of room Example: 1130/2* 20 ft. =28.5 Hz so you will start gain 12 db/octave starting at 28.5.. This mean at 14Hz you will be up 12 db. Room gain is not boundary gain which is usually 2-5 db. Edited February 14, 2015 by derrickdj1 Quote Link to comment Share on other sites More sharing options...
DizRotus Posted February 14, 2015 Author Share Posted February 14, 2015 Derrick, I'm still planning to tap your expertise regarding the setup of the iNuke. It's unlikely to be to that pont this weekend. I'll shoot an email and/or call. Thanks, Neil Quote Link to comment Share on other sites More sharing options...
bhenry Posted February 15, 2015 Share Posted February 15, 2015 I'm intrigued by this thread.....I have two water-logged RSW-15's that I'd like to use for parts and make a DIY sub (or two). Just out of curiosity: I also have two RF-7's that could be used as donors, could the drivers from those be used in a small sub? Quote Link to comment Share on other sites More sharing options...
DaveWJr Posted February 15, 2015 Share Posted February 15, 2015 I'm intrigued by this thread.....I have two water-logged RSW-15's that I'd like to use for parts and make a DIY sub (or two). Just out of curiosity: I also have two RF-7's that could be used as donors, could the drivers from those be used in a small sub? The RF7 drivers don't have the throw needed to be great as subwoofer drivers. They're optimized for their intended application. Quote Link to comment Share on other sites More sharing options...
DaveWJr Posted February 15, 2015 Share Posted February 15, 2015 Every time Dave whips out the science I have to read his post about 5 times. You too? Heh my wordiness is often made fun of at the office. Concise is not my middle name Quote Link to comment Share on other sites More sharing options...
bhenry Posted February 16, 2015 Share Posted February 16, 2015 That's what I figured. I'd love to figure out something cool to do with that stuff since it's basically trash now but I refuse to put it in the garbage. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted February 16, 2015 Share Posted February 16, 2015 I'm intrigued by this thread.....I have two water-logged RSW-15's that I'd like to use for parts and make a DIY sub (or two). Just out of curiosity: I also have two RF-7's that could be used as donors, could the drivers from those be used in a small sub? Figure out the internal volume of the RF-7 enclosure, and the port length and diameters and build a pair of beasty bass bins. They would be good from 32 - 2200Hz. Quote Link to comment Share on other sites More sharing options...
Bryant0086 Posted February 17, 2015 Share Posted February 17, 2015 Awesome thread !! Some of it might as well be in Mandarin though. There is a great deal of laws and calculations involved in audio that I am not even remotely familiar with. I love to learn though. Bryant Quote Link to comment Share on other sites More sharing options...
mustang guy Posted February 17, 2015 Share Posted February 17, 2015 Awesome thread !! Some of it might as well be in Mandarin though. There is a great deal of laws and calculations involved in audio that I am not even remotely familiar with. I love to learn though. Bryant There is indeed a lot to learn. I am just scratching the surface of it, but every minute is enjoyable. What are you most interested in with audio? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.