Members Jess Posted February 25, 2007 Members Share Posted February 25, 2007 Well folks after completing 3 gigs this weekend all done with aux fed subs I'm hooked. The rig sounded just like it was meant to, tight, punchy, and unmuddy(is that a word?) Anyways my kik has never sounded so fat and defined and the vocals were crystal clear. Thanx to all those that helped me out on this one....very cool. Jess. Link to comment Share on other sites More sharing options...
Members death metal jim Posted February 25, 2007 Members Share Posted February 25, 2007 Cool , I was going to try this out this weekend, but I ran out of time . I did run some side fills for the vocals and guitars . It help my mix alot . Vocals were always to loud at the back of the room and almost couldn't be heard at the front of the stage.Next weekend I should have time to try the aux feed subs. Did you use a separate eq for the subs? Link to comment Share on other sites More sharing options...
Members Jess Posted February 25, 2007 Author Members Share Posted February 25, 2007 Cool , I was going to try this out this weekend, but I ran out of time . I did run some side fills for the vocals and guitars . It help my mix alot . Vocals were always to loud at the back of the room and almost couldn't be heard at the front of the stage. Next weekend I should have time to try the aux feed subs. Did you use a separate eq for the subs? Heya Jim......No man...No GEQ on subs at all, or top boxes for that matter. I hardly used my FOH graphic anyways and having the subs with there own mix really seems to define the entire frequency spectrum. If you have good quality matched FOH boxes i think you will find that your GEQ's will gather dust rather rapidly.... Jess.... Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 26, 2007 Members Share Posted February 26, 2007 It's not the end-all. A properly set up system with subs crossed from the main mix can easily sound very good as well. Out of the last 100 acts that came though our venue (a 100 seat A citcuit type place) not a single one opted for aux fed subs, even though the system easily supports it. One listen to the PA and they decide there's no significant benefit for their needs. Not saying it COULDN'T help in some instamces, but it should NOT be a night and day difference in a PROPERLY set up system. Link to comment Share on other sites More sharing options...
Members Jess Posted February 26, 2007 Author Members Share Posted February 26, 2007 It's not the end-all. A properly set up system with subs crossed from the main mix can easily sound very good as well. Out of the last 100 acts that came though our venue (a 100 seat A citcuit type place) not a single one opted for aux fed subs, even though the system easily supports it. One listen to the PA and they decide there's no significant benefit for their needs. Not saying it COULD help in some instamces, but it should NOT be a night and day difference in a PROPERLY set up system. Agreed Andy, but for my applications it has certainly improved the over all sound of the P.A. jESS..... Link to comment Share on other sites More sharing options...
Members preacherman672 Posted February 26, 2007 Members Share Posted February 26, 2007 In a properly set up 50-100k installed sound system that has been extensively tuned to the room by qualified professionals where there is not an extremely bass heavy mix there is little benefit. That however is NOT what 95% of the people posting on this forum have at their disposal. IME aux-fed subs works spectacular on MI grade gear with average soundmen. It also is almost a necessity on really bass heavy mixes. Les Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 26, 2007 Members Share Posted February 26, 2007 I must be terribly out of touch with what you guys are doing and seeeing. The last several service calls involving systems where they had "techs" that supposed to have known their stuff were rather embarrasing for me to do. One involved an insert cable left in the console causing the channel to be "dead" Another involved runaway feedback (of course with a couple of blown HF drivers) on a lav microphone and the cause... the compressor that was inserted on the channel at about 6:1, "somebody" had turned the threshold all the way down assuming they were turning the compressor off. Of course they increased the gain to get enough volume and as soon as the paster stopped talking, the comp would release and the gain would go up. Classic case of not understanding the process. And you would think the G.R. indicators would have given it away. Got to love the church sound fantasy magazines and their tech tips! The third involved distortion, mysterously came without any cause... or so I was told. Turns out the distortion was on the subs (some horn loaded 18's) and it was hard to pinpoint due to the location of the boxes within the structure (large church MPR/gym). I start troubleshooting and the tech was telling me about how the made all these great improvements with tips from the interned and how they dramatically improved their system headroom with their new DriveRack. Ahhhh, now I've got some information to go on. Turns out they had bought an additional amp and bridged one into each pair of subs (2450's) 1200 watts per box. I reviewed the programming on the DR and find about 12dB of boost at 35Hz and the sub band was already like 9dB greater then the tops. Holy crap, equiv. of almost 20dB of boost below the cutoff of the enclosure. Pull the drivers and they are pretty floppy and you could see where the surrounds hit the mounting surface. Totally shot. All the while the guy is telling me how great the system is and all the wonderful advice he got from the church sound forum (of some sort). When I told him what was wrong, he had the nerve to argue with me... I'm sitting there with 4 of his totally trashed (and expensive) drivers and he's telling me I don't understand. Yeah, maybe I'm out of touch, maybe not, but I have never blown drivers like this ever, in many thousands of shows. I submit the estimate to his superiors and they come unglued (it wasn't cheap) when I explain to them why they failed. End result? The tech was demoted and the system restored to reasonable parameters. How did it happen? Turns out the guys had a runaway feedback accident at low freq (with that much gain at Then there was the mysterious music that bled through the sound system (comes and goes) whenever it was on, radio interference from a country station they called it. Good grief, if they had even thought about it for a minute they would have realized how stupid that was. Turns out one of the guys had hooked up an extra CD to an aux return and it was a CD player that had an auto start feature (Sony) and whenever they powered the system up (master power switch) the CD player would autostart and the aux return in the master section was being used for that input had been left up. Again, pretty basic troubleshooting would have solved this "service stopper". They had to do the morning service without PA because the music was distracting. So this is what I see out in the field on a pretty regular basis (in adddition to some more common failures) and it seems as though it's caused by folks going beyond their capabilities and missing the basics in their quest for nirvana. Get the basics down 100% first, most of the audience would appreciate that over the cute little frills. Oh, and the same goes for mixing... get the damn basic structure of the mix together first before worrying about comps, gates, and effects. Nothing rubs me the wrong way more than somebody screwing with the effects in their quest for the perfect reverb and misses the fact that there's an acoustic guitar on stage that's carrying (or supposed to be) the rest of the band for example. [rant off] Link to comment Share on other sites More sharing options...
Members preacherman672 Posted February 26, 2007 Members Share Posted February 26, 2007 Interesting stories as I see much of the same thing in most of the churches that I install systems or run sound in. I don't really see how that applies to the topic at hand other than your rant about getting the basics right first, with which I totally agree. If you don't understand the basics of mixing and setting up, you should NEVER try to do something like aux-fed subs. I personally don't think effects (including comps and gates) should be used by about 90% of the people I see mixing. You can get a very nice mix without the effects, albeit you can get a better mix with them properly applied. The problem I see is the same one you stated, many people are trying to get the "perfect" reverb/comp/gate/delay and mess up the entire mix because of it. Still not sure how this directly applies to the situation at hand, but oh well, it's late and I'm bored Maybe I'm missing something. Les Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 26, 2007 Members Share Posted February 26, 2007 Just trying to put priorities in perspective, highlighting how "good ideas" often get scrambled into something worse than the original issue. Link to comment Share on other sites More sharing options...
Members preacherman672 Posted February 26, 2007 Members Share Posted February 26, 2007 Just trying to put priorities in perspective, highlighting how "good ideas" often get scrambled into something worse than the original issue. :thu: Link to comment Share on other sites More sharing options...
Members session_of_jam Posted February 26, 2007 Members Share Posted February 26, 2007 could someone bump the original thread about aux fed subs? Id like to read it. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 26, 2007 Members Share Posted February 26, 2007 Another service call this morning, distortion in the high end and they were sur it was blown drivers. We installed the system and powered it suitable and with limiting and our usual protection as the cabinets are flown about 25 feet in the air. BEFORE going up in a lift, I troubleshoot and discover the problem in aboout a minute... somebody had gone in on the house EQ and boosted 100Hz to +15dB, causing the eq to overload and clip the filter loop amp. Sounded nasty but wasn't the driver's fault. Seems they had an event where the "wanna-be pro" sound guy felt the need to "tune up" the system and then complained that it sucked and was all distorted. Hmmm... wonder where he got his education??? Link to comment Share on other sites More sharing options...
Members alcohol Posted February 26, 2007 Members Share Posted February 26, 2007 I'm thinking about doing this on a March 24 gig. If I missed it, please excuse me. I'm only interested in having the kick drum go to the subs. So for the kick, I would send the kick to the mains and also via th aux send to the subs, but through a crossover first? Have no crossover on the mains? This is for a small room that swallows the bass drum. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 26, 2007 Members Share Posted February 26, 2007 Yes, but you will also be taxing the mains more in the low end compared to no high pass. Another alternative is to split into 2 channels, send the signal to the mains with the channel HPF engaged and to the aux on the channel w/ the HPF out. Link to comment Share on other sites More sharing options...
Members death metal jim Posted February 27, 2007 Members Share Posted February 27, 2007 the mixer i just ordered has a 100 hpf,my xover is set at 100.is there any point for me to have aux send subs Link to comment Share on other sites More sharing options...
Members boomerweps Posted February 27, 2007 Members Share Posted February 27, 2007 the mixer i just ordered has a 100 hpf,my xover is set at 100.is there any point for me to have aux send subs Yes. It's worthwhile trying it. Filters are not fences. They attenuate the signal down (or up) at a certain rate. So high passed signals at 100Hz with a 12dB per octave filter drops the signal 12dB at 50Hz. How much signal energy is still there at 70 or 80Hz? Completely removing undesired signals from the subs clears up their sound and, IMHO allows them to more effectively use the power provided. You really don't need to use a graphic EQ over the narrow band going into the sub. A decent HPF & LPF in a seperate crossover is all. Another advantage to Aux fed subs is the ability to seperately boost (or lower) the subs output. Yes, you can do this on a graphic EQ feeding a normally crossover system but graphic filters affect the frequencies quite a distance from the fader's center frequency. Boomerweps Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 27, 2007 Members Share Posted February 27, 2007 Another advantage to Aux fed subs is the ability to seperately boost (or lower) the subs output. Yes, you can do this on a graphic EQ feeding a normally crossover system but graphic filters affect the frequencies quite a distance from the fader's center frequency.Boomerweps You can do this more effectively with the sub out level control on the crossover. Link to comment Share on other sites More sharing options...
Members bazza54 Posted February 27, 2007 Members Share Posted February 27, 2007 90% of small systems that use aux subs suck! The operators however think that they are wonderful because they have read that this is the way to go and how much better it is than just wiring the subs in parallel to the main speakers. Well I guess if you are not using crossovers then anything is an improvement. Lack of crossovers is the main problem I see on these small systems. The subs (18 Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 27, 2007 Members Share Posted February 27, 2007 Once you are 12dB down (dBv), you are effectively sending 1/16th the power to the device. There's an exponent in the power equation that works to your advantage here. Link to comment Share on other sites More sharing options...
Members boomerweps Posted February 27, 2007 Members Share Posted February 27, 2007 You can do this more effectively with the sub out level control on the crossover. Yes, IF you have the crossover at FOH or are using a remote (laptop control to DSP) to the one in the amp rack. Boomerweps Link to comment Share on other sites More sharing options...
Members boomerweps Posted February 27, 2007 Members Share Posted February 27, 2007 No doubt one of the engineers here will correct me if I am wrong, but being pedantic the filter frequency is usually quoted at the -3dB point so your 100Hz filter will be down 15dB at 50Hz. With a decent system that signal will then hit the main crossover which could be rolling off at upto 48dB per octave, 24dB per octave is certainly common. This attenuation needs to be considered as well. Steeper filters require more components, more money in production. Smaller systems generally have cheaper mixers with lesser filters. The example I gave of a 12dB per octave HPF set at 100Hz means (forgetting any -3dB downpoint, that varies when Marketing & labeling gets involved) means a -5dB signal is still produced at 80Hz. That means it's still being heard. Boomerweps Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 27, 2007 Members Share Posted February 27, 2007 Yes, IF you have the crossover at FOH or are using a remote (laptop control to DSP) to the one in the amp rack.Boomerweps Or when you are setting up and tuning the system, turning it down at the amp rack or the powered sub is not all that difficult either. Link to comment Share on other sites More sharing options...
Members Danny (NS::U) Posted February 27, 2007 Members Share Posted February 27, 2007 Let me just chime in and say that I feel that any variation on aux fed subs is more of a style of working than a "fix." I use a variation on aux fed subs for my own rigs, and I really love having a "boom!" knob. However, I personally have had no real problems mixing "straight." I really like being able to have another avenue with which to exert detailed control over sub information (is that an oxymoron - detailed control over sub information?), but it's not something that I see as an absolute must. Just an opinion, mind you. Link to comment Share on other sites More sharing options...
Members preacherman672 Posted February 27, 2007 Members Share Posted February 27, 2007 90% of small systems that use aux subs suck! The operators however think that they are wonderful because they have read that this is the way to go and how much better it is than just wiring the subs in parallel to the main speakers. Well I guess if you are not using crossovers then anything is an improvement. Lack of crossovers is the main problem I see on these small systems. The subs (18 Link to comment Share on other sites More sharing options...
Members preacherman672 Posted February 27, 2007 Members Share Posted February 27, 2007 You can do this more effectively with the sub out level control on the crossover. Not unless you want to adjust for the entire mix. In a bass heavy mix this really shows as even with crossovers engaged at 24db per octave you will still get substantial plosives in the subs from the vocal mics. Especially shows up if someone is speaking between sets/songs. Les Link to comment Share on other sites More sharing options...
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