Members caseyjf Posted February 23, 2009 Members Share Posted February 23, 2009 Is the search messed up? Everytime I search something, I'm only getting about 5 results when I know I should get more... Anyways, we played a show on Saturday night in a big open room, and the subs sounded great. A friend of our bass player is the "sound engineer" (that may be a self-proclaimed title) for his church. We usually put dual 15"s on top of single 18"s on each side of the stage. The suggestion made was that we should stack 2 18's on top of each other on one side, and elevate the other speaker with a 'dummy sub'. He claimed that not coupling the subs has a negative effect. I remember reading a post that had a link to some kind of dB rating for 4 front-loaded 18" subs arranged in various positions to visually show how placement affects sound. Anyone recall this link? I didn't want to argue, but I wasn't sure how not coupling a sub could have a negative effect? Link to comment Share on other sites More sharing options...
Members samkokajko Posted February 23, 2009 Members Share Posted February 23, 2009 It's negative relative to coupling. It depends on which one is your zero point. Coupling subs has a benefit, not coupling is just a sub. Link to comment Share on other sites More sharing options...
Members Coaster Posted February 23, 2009 Members Share Posted February 23, 2009 the benifits of coupling subs in a single point source has to be weighted against desired coverage pattern. none of this is a simple issue. dave rat has a lot of reading on his blog and even he states it is somewhat trial and error as well as knowledge and experience to get what he tries to achieve. Link to comment Share on other sites More sharing options...
Members jwlussow Posted February 23, 2009 Members Share Posted February 23, 2009 We generally get the best sound when we can put both of our MRX 518s together at the front & center of the stage. Only a few of the places we play have an elevated stage where this set up is feasible, though. Most people never even notice a difference between having them on the sides or together in front. Link to comment Share on other sites More sharing options...
Members mshifflett Posted February 23, 2009 Members Share Posted February 23, 2009 I wouldn't think that not coupling two single 18" front-loaded boxes would have a negative effect. Usually this happens more with horn-loaded subs. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 23, 2009 Members Share Posted February 23, 2009 Coupling affects all sound sources. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted February 23, 2009 Members Share Posted February 23, 2009 Is the search messed up?Totally! Wish they'd fix it ... Link to comment Share on other sites More sharing options...
Members mshifflett Posted February 23, 2009 Members Share Posted February 23, 2009 Coupling affects all sound sources. Oh definitely. I was just speaking of negative effects from not coupling sub boxes. Hey and I am probably totally wrong on this one too but I would think the negative effects would be greater on horn-loaded boxes than front-loaded. We used some double 18" JBL boxes for a while and didn't notice that much difference when split to each side, but noticed quite a bit of difference when the same was done with the horn-loaded boxes. Like I said I am probably way off the mark here and can only speak from what I have experienced personally. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted February 23, 2009 Members Share Posted February 23, 2009 We generally get the best sound when we can put both of our MRX 518s together at the front & center of the stage.Putting them both on the same side is often better than splitting them up. Make sure they aren't about 3.5' from a wall as they will tend to disappear sonically. Usually one side or the other is better for boundary re-enforcement - against a wall works best. I usually angle them in towards the dance floor. Link to comment Share on other sites More sharing options...
Members Zeromus-X Posted February 23, 2009 Members Share Posted February 23, 2009 I played the same venue twice recently, same equipment, same songs between the breaks for the most part, but put the subs together at the center of the stage this past time. Previously we split them to the sides. The difference was huge on the dance floor -- with them split, yeah, we could shake the building, but it wasn't as crazy on the dance floor in front of the stage. With them in the center, the dance floor had massive amounts of bass, and the rest of the room had a "just right" amount. The only negative was that in between each set of songs they'd walk forward about an inch and have to be slid back! Link to comment Share on other sites More sharing options...
Members lifeloverwg Posted February 23, 2009 Members Share Posted February 23, 2009 The benefit of putting your two subs next to each other, is that you gain a free 3dB of level from the coupling of the two woofers. That's the same increase as doubling the power to your subs. The negative side is that you may need the wider coverage you get by spacing them apart more than you need the increase in SPL. And, you may prefer to have the power alley effect on the center dance floor or seating area that is a common result of seperated subs. Then factor in the proximity of other boundarys or lack there of, as they will affect any real world gain or loss you actually attain. Do a google search on power alley and boundary cancelation for plenty of good reading. I tend to group mine together close to the center, but ours are only 15" high when on their sides so I can get away with center placement more commonly and we are in smaller venues. If you have time, moving them around is really the best way to tell what will work best. Good luck, Winston. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted February 23, 2009 Members Share Posted February 23, 2009 The only negative was that in between each set of songs they'd walk forward about an inch and have to be slid back!Rubber mats prevent that and scuffing up the floor and cabs . Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 23, 2009 Members Share Posted February 23, 2009 Note the +3dB is only a theoretical amount and that it's not uniform for all frequencies. In fact, you may get an average of 1.5dB "gain" over part of the bandwidth. Also, this benefit starts to disappear after you reach 8 or so drivers because maintaining the critical spacing distance becomes a problem and destructive interference robs any gain. Link to comment Share on other sites More sharing options...
Members frankiefeedback Posted February 24, 2009 Members Share Posted February 24, 2009 I did a show recently where the band and PA were moved halfway through the night. My single 18" sub ended up about 3' in front of my mains (mains on stage and sub on the floor) and about 4' from the wall. The bass disappeared from the mix... I was pushing faders until I saw the clip lights on the sub amp. I was pretty amazed on how well the sub was canceled out, I mean there was almost NOTHING there! I do run the tops full range, with a single 18 a little help with low end goes a long way with my system. Now, I line the sub up directly in line with the tops. It goes right next to the main that is in the largest part of the room and goes on the center stage side of the main. I've been gettin good results from this setup. Link to comment Share on other sites More sharing options...
Members lifeloverwg Posted February 25, 2009 Members Share Posted February 25, 2009 I did a show recently where the band and PA were moved halfway through the night. My single 18" sub ended up about 3' in front of my mains (mains on stage and sub on the floor) and about 4' from the wall. The bass disappeared from the mix... I was pushing faders until I saw the clip lights on the sub amp. I was pretty amazed on how well the sub was canceled out, I mean there was almost NOTHING there! I do run the tops full range, with a single 18 a little help with low end goes a long way with my system.Now, I line the sub up directly in line with the tops. It goes right next to the main that is in the largest part of the room and goes on the center stage side of the main. I've been gettin good results from this setup. The 4' from the wall was probably the culprit. That would pretty much cancel all the 70hz from that sub. The rule of thumb for subs is closer than three feet or further than eight feet from a boundary. Winston Winston Link to comment Share on other sites More sharing options...
Members honestjohnny Posted March 3, 2009 Members Share Posted March 3, 2009 What about behind the band, facing a corner? Floor coupling, wall coupling, and sortof a horn-loading effect. Put the bass player on the same side and he'll need less bass in his monitor/from his amp. Link to comment Share on other sites More sharing options...
Members mshifflett Posted March 3, 2009 Members Share Posted March 3, 2009 What about behind the band, facing a corner? Floor coupling, wall coupling, and sortof a horn-loading effect. Put the bass player on the same side and he'll need less bass in his monitor/from his amp. We put a single LAB sub pointing in to a corner to the side of the stage one night in a smaller 250 capacity bar and it shook the place. In fact, it was too much on stage and triggered the kick trigger several times! Link to comment Share on other sites More sharing options...
Members honestjohnny Posted March 3, 2009 Members Share Posted March 3, 2009 It's not the size, but how you use it! I'm glad to see people discussing subs and sub placement. There are so many great ways to achieve good live sound with all frequencies represented, it just requires people to be open-minded and willing to spend a little more up front. For example, active high power/sensitivity SMALL mains and monitors (8's, 10's) and active subs with good power/sensitivity and placement can give you a much better sound for the $$$ than the packaged deal powered mixers with 15" mains. But in the former, you HAVE to have the subs! Without them your sound is going to be terrible! You just have to get past the band moaning about spending a little extra, until the first gig when they can FEEL the kick and bass, as well as hearing the mids and highs! This also means that bands can get away with hauling less to achieve their sound. Guitar goes from a 4X12 100watt to a nice all tube cranked boutique 15 watt 1X12, 2X10, or 3X8 (8's are better, but not as good as 6's), bass can drop down to a 300 watt small stack, single cab or :gasp: goes direct. And the vocalists can hear themselves better, which is always good for them:facepalm: Then you might have room on stage for horns and percussion! Unfortunately, you can't make the keys player happy, so just give up:poke: Link to comment Share on other sites More sharing options...
Members MrBassman Posted March 29, 2009 Members Share Posted March 29, 2009 Tagging on to this post for some related questions; putting some pieces together for the latest band project. Room and stage considerations do limit placement wondering about pros and cons of different placement. Got a pair of Community 2x15 subs 18"x18"x34". Nice rectangular boxes making center placement more of an option. Taking a typical 3' high stage with a average 30' wide room... would horizontal alignment or vertical alignment be a better choice. Taking a typical small stage setup with half the band on stage (drums, keys,bass) and half on floor in front of stage (guitars and singer) would placing subs in front of stage center behind the singer and guitars be disaster in waiting? Would the vocalist and guitarists poop their pants and start crying halfway through the first set? Link to comment Share on other sites More sharing options...
Members jwlussow Posted March 29, 2009 Members Share Posted March 29, 2009 Tagging on to this post for some related questions; putting some pieces together for the latest band project. Room and stage considerations do limit placement wondering about pros and cons of different placement.Got a pair of Community 2x15 subs 18"x18"x34". Nice rectangular boxes making center placement more of an option.Taking a typical 3' high stage with a average 30' wide room... would horizontal alignment or vertical alignment be a better choice.Taking a typical small stage setup with half the band on stage (drums, keys,bass) and half on floor in front of stage (guitars and singer) would placing subs in front of stage center behind the singer and guitars be disaster in waiting? Would the vocalist and guitarists poop their pants and start crying halfway through the first set? A sub behind the singer elevated on a stage would cause all types of problems. The stage will vibrate and all mics will pick that up. I'd place the sub horizontally in front center stage on the ground. I suggest that you never elevate the subs, especially onto a wooden platform. Link to comment Share on other sites More sharing options...
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