Which PA sub?

Discussion in 'Location Recording' started by vibrations1951, Aug 11, 2014.

  1. vibrations1951

    vibrations1951 Active Member

    Hello folks, quick question I hope:
    I'm putting together a modest PA for our 4 piece group.We have bass+guits-own amps miked at times or DI, light keys-Roland thru PA only, 4vox, sml/med venues. I want it compact and light in weight for lugging.
    I already have: Mixwiz wz3 16.2 mixer, DBX eq, QSC PLX 2402, 2 old Community 15”passive mons with tweeter horns for fills or sell?. 2 hotspots.
    My plan is to add:1or2 cheapo Beh F1320D pwrd mons, Mains on Passive EV TX1122,
    My dilemma is: 1 pwrd sub-EV ZXA1 12" (561b)or EV ELX118p, 18" (70lbs).

    I think the 12" in the 2way mains will help the clarity an definition and a good sub will fill it all out. So I'm torn between the 2 subs I mentioned and wondered if I could get by with the ZXA1 or end up having to get another later?
    Thoughts? Thanks!
     
  2. vibrations1951

    vibrations1951 Active Member

    OOPS! I forgot to mention that the music is mostly medium rock mix, with complex strong focus on vox. Heart, Moodie Blues, CNS, Elton John, The Band, Orpheus, Clapton, Pink Floyd etc. etc. Yes, I'm old!
     
  3. Boswell

    Boswell Moderator Distinguished Member

    From my long experience of managing live sound, there are very few venues where I have found a single centrally-sited sub works well, not to mention the stage clutter it can create. In your position, I would go for the conventional sub at the base of each of the L + R loudspeaker stacks. I would also plan on feeding a separate mono (x.1) line to both subs from the mix position rather than use the built-in crossovers in the subs.

    Preservation of acoustic output phase through the crossover range can be a problem when using different manufacturers of mains and subs, so I would consider hiring in a pro to do a frequency and phase sweep check once you have decided on the subs you need. It may mean either positioning the main speakers forward or backwards a few inches relative to the sub, or else using an electronic phase shifter in the x.1 sub filter at the mix station.
     
  4. vibrations1951

    vibrations1951 Active Member

    Thanks Bos. I like the idea of the 2 subs with sticks above for mains. So I could use the 1/4 outs on the mixwiz for the separate sub feeds or split out the mono mix from the board and assign my sub aux mix to that? I'm in a very remote area with none around for 125 miles or more that could do the phase testing. I'll have to trust my ear I guess.
    What are your thoughts about using 12s verses 18s for subs? I have no way to test any equipment and that would be a 250 trip one way to the closest store for the EV's I'm leaning towards.
     
  5. Boswell

    Boswell Moderator Distinguished Member

    I would not have thought that 12" subs would be worth adding - if you are going to the trouble of including subs in your stack, then 15" or even 18" would be the way to go. Don't forget that 18" boxes can be beasts to schlep.

    You can do a reasonable job of phase checking the main/sub crossover yourself using an omni microphone and simple audio interface with one of the several PC programs available for this type of task. Do it outdoors to avoid room reflections, but choose a still day. Position the combo speaker set as far off the ground as you can manage, again to avoid reflections. You don't need the pole between the mains and the subs for this job as long as you position the mains in the same place horizontally relative to the sub as they would be if you were using a pole. Fractions of an inch make a difference, even at these frequencies.
     
  6. vibrations1951

    vibrations1951 Active Member

    Great advice Bos. I have never tried any of those PC programs for testing phase but I could probably manage this OK. The 70lb EV's may be the way for me to go. They are 18's and only 70lbs.. Maybe I can have the young guy in the group do the heavy lifting!
    Again Bos, Thanks so much for the feedback...

    Does anyone here have experience with the subs I have listed above?
     
  7. vibrations1951

    vibrations1951 Active Member

    Does anyone here have experience with the subs I have listed above?
     
  8. Boswell

    Boswell Moderator Distinguished Member

    Here are a couple of papers about subwoofer phase alignment:
    First
    Second

    The second one is more detailed, and may be over the top for what you need.
     
  9. vibrations1951

    vibrations1951 Active Member

    Wow! Great stuff....no time right now but I'll dig into it this eve. Thanks Bos!

    So I'm still wondering is the EV ZXA1 12" sub is familiar to anyone.
    I had the weight wrong and it is under 50lbs. Would it be wise to put a pole on this and have the 2 way that weighs a little less on top? Safe??? Sounds iffy to me but I have no experience with "sticks".
    Thanks
     
  10. dvdhawk

    dvdhawk Well-Known Member

    It's good to know musical styles you're trying to cover, but size of typical venue is a factor, and overall loudness. Some guys our age play outrageously loud, due to the hearing loss from years of playing just ridiculously loud. Other guys our age play at a very subdued volume and have earplugs in to boot. So where would you say your band falls on the Front of House volume scale?

    I definitely like your idea of a 12" 2-way main cabinet. A 15" 2-way never seems to be as smooth through the vocal range as a 12". You obviously get more bottom from the 15" cabinet, but at the expense of the clumsy crossover that does not usually flatter vocals.

    As far as your subs, I'm more of a passive speaker guy, so my experience would be with the passive version of the ZX1 sub. I'm doing an installation now that uses two of them to complement a pair of VLA vertical line arrays. The 12" sub isn't going to move as much air as a 15" or 18" sub, consequently they'll never go as deep, or be as loud - but they do add a very tight and well controlled bottom that drops off pretty quickly below 50Hz or so. If you're looking for earthmoving cardiac-massage-bass-impact, a 12" sub is not going to do it (unless you go to a whole different level of spending). But if you're mostly about the vocals, and your bass player has a good strong rig, and you just want to punch up the bass and kick - you might be surprised how well a 12" can do the job. If you're playing at high volumes and there is a lot of the Pink Floyd type material, you'll probably wish you had bigger subs. [man I wish we lived closer together, I'd let you borrow some things to try out]

    Possibly the best sounding bass rig I've ever heard used 5" drivers. (lots and lots of 5" drivers) The perfect balance of definition and building rattling low-end.


    Purely as a point of reference - I have numerous scaleable systems for my own use, and the occasional rentals. I probably have enough gear to send out 4-5 different systems on any given day, if there were that much demand in this neck of the woods. Ranging from a couple small systems that use Yamaha EMX powered 8-channel mixers and a pair of Yamaha BR15 for smallish endeavors, up to the big club / small outdoor system that uses 4 of these .pdf']JBL SRX728s dual 18" subs, to go with 4 of these .pdf']JBL SRX722 full range cabinets, and a half dozen of these JBL MRX512m, Crest / Crown / QSC power amps - teamed up with whatever Soundcraft or PreSonus mixer best fills the bill. Small potatoes compared to a Madmax system, but still a pretty robust club system (and beyond) - when provided with enough electricity. It's funny, but when I work with guy roughly my own age, they say, "I can't believe how light your stuff is." When I've got a band of 20 year olds helping lug the system in… you guessed it, "What's in this? Lead? Cement? Why are these things so heavy?"

    Somewhere in the middle of the range, is a system I take out from time to time that uses a pair of the VLA vertical line arrays, with a pair of even smaller E-V SB122 12" subs (usually Crown XTi powered with a Soundcraft FX-16 board). It's a remarkably small and lightweight system that can easily fit in the back of my small pickup truck and set up in a matter of minutes. The VLAs are very lightweight at about 20lbs each, but uncommonly tall at over 6ft. The SB122s weigh in at 33lbs each. The SKB mini Gig Rig rack with the mixer and amp(s) is all pre-wired and the only thing of any weight. Anyway, I can't tell you how many compliments I get when I take that system out - indoors, outdoors, it doesn't matter. Countless people (musician-types, and folks with no audio background) will flock to the 'stage' during the breaks, or at the end of the show, to ask about the sound system and say how amazing the sound was. I'm not trying to kill anybody with volume, but with anything from an acoustic solo artist to a 3-pc rock band, this system has been the ticket if I don't want to pull a trailer full of JBL. The coverage of the VLAs is extremely impressive, but without EQ-ing the crap out of them, they start dropping off pretty sharply below 100Hz, so if you're just micing vocals that's probably low enough. The VLA uses 20 x 3" drivers, but oddly, still produces a very dramatic bump in the 200Hz range which I usually have to EQ to some extent. Then they drop back closer to baseline by the time they get down to 100Hz. Add the E-V 12" sub and it does a solid job giving you the next octave down to 50Hz. Sometimes I bi-amp that system using a dbx Driverack, or sometimes just using the crossover built-into the XTi amps set at 100Hz. The SB122 are a good fit for the VLAs. And yes, I have tried the JBL subs with the VLAs and the JBLs overshadow the VLAs pretty significantly. To get the thunderous low-end that configuration offers, the JBL subs have to be dialed back to the appropriate volume.

    So I guess the bottom line of all this is, I have circumstances where a 12" sub is ideal. You trade-off the super-low frequencies and extra sound pressure levels, and that's not necessarily a bad thing. For example, the church install I'm starting now, tight/punchy bass is more appropriate than big booming bass. Coffee-house size places and smaller bars it may be a good fit for you too, but at the end of the day a 15" might be a good safe bet 'tweener'.
     
  11. vibrations1951

    vibrations1951 Active Member

    Hey Dave
    Really comprehensive answer...I'll try to absorb later. I did try to send you a private conversation here at ROG so maybe that will help. Give it a look.

    I'll try to get back at you later tonight.

    I sure wish we were closer by as well. Where I live I'm used to not being near anyone! LOL!
    Later
     
  12. dvdhawk

    dvdhawk Well-Known Member

    The ZX series recommends you stick with a very small top cabinet if you're using the pole mount, due to the small footprint and tip-factor. They make an 8" 2-way that is what it was ideally designed to be mated with.
     
  13. vibrations1951

    vibrations1951 Active Member

    D the music we are doing so far is like some Heart, Elton John, CSN, Moodie Blues, Clapton, Orpheus, The Band, Beatles etc. No chest thumping needs!
    I had the same worries about the zx series and may be better to just bite the bullet and go for the ELX118P's. More wt. and foot print as well as capability for deeper stuff if we go there or I rent out my services to other groups.

    I did sent you some private messages and mostly wanted to talk to you about advice and possible things you may have to sell.
    Anyway, what do you think of building up to the ELX118P's with poles and the Passive EV TX1122 on top driven by my QSC PLX 2402? I couldn't likely purchase all at once but I'm in no great hurry right now.
     
  14. dvdhawk

    dvdhawk Well-Known Member

    I didn't receive any messages JP.

    The ELX isn't that much larger of a footprint really (About 2 ½" wider and 4 ⅝" deeper, less than a square foot difference) and it's a solid dollar value. The only other powered sub I'd look at in that price range might be an 800w Yamaha 15".

    The system you're proposing should do nicely in a reasonable sized room. I like the TX series. The only other thing I was running some numbers on, was whether your money would be better spent getting a comparable powered cabinet for mains, and use the PLX to power passive monitors (maybe the ones you already own). Kicking it around on a spreadsheet, we'll see what happens.
     

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