Using 2 JBL PRX835's (or other 3 ways) without a sub ?

Discussion in 'Live Sound [BG]' started by pfschim, Jul 28, 2019.


  1. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    Curious about more experienced opinions a mains box like the JBL PRX835.
    I guess the same questions would apply to the bit more expensive QSC KW153 or EV ETX35P.

    The JBL is a 3 way bass reflex box 15" woofer, 6.5" mid and 1.5" compression driver for highs.
    138db peak SPL, +/-3db response is listed as 42hz-20khz (there is something in the material that mentions 39hz using "boost" which I presume is a DSP driven EQ bump down low).

    I'm wondering if a pair of these would work ok without a sub ? Seems like they go down pretty low on their own. I'm sure adding a sub would make such a system more robust but I am considering ways to not have to deal with more than 2 mains if I could.

    Any thoughts.
     
    Last edited: Jul 28, 2019
  2. CBBass123

    CBBass123

    Oct 18, 2005
    Texas
    Depends on venue size. I've filled in bass for my buddy's band with a small combo amp and he only ran 2 srx835p speakers setup in full range mode. For smaller indoor gigs, it was fine. Those speakers have nice lows as long as they are coupled to the ground.
     
  3. DonaldR

    DonaldR

    Mar 26, 2012
    My drummer has two PA: one set with a pair of Mackie 1530 (similar to the PRX835) and another set with a pair of Yorkville NX55 (12" top) and a Yorkville LS710 sub. I way prefer the second kit. I don't like PA with 15" speakers, much prefer 12" tops and a sub, more balanced.
     
  4. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    Ft.Worth/Dallas
    1964 Audio artist, Fractal Audio Beta Tester
    Can you do it? Yes!
    Should you is the real question.
    For me, it would depend on the style of music. For rock stuff in smallish venues you should be fine. But if you are doing dub, hip-hop, anything with a lot of "thump", or mid-size+ venues, then I'd recommend subs.
    Heck, try them out at a gig and see how they do.
     
    pfschim likes this.
  5. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    yeah, I'm thinking I could do just that ... try them without a sub and if they don't handle it, just add a sub.

    OTOH, I'm kind of torn on this because I could just bite the bullet and get the mains and a sub (probably will go with 12" mid-range mains from one of the makers ... EV, JBL, QSC) and be done with it. The advantage of the 3 ways would be if they could cover the gigs without requiring a sub. They are quite a bit bigger, heavier and more expensive than the mains and sub approach.

    this line of questions is all part of my "do I want to, or do I not want to ?" challenge regarding owning a PA. Problem is, part of me really does NOT want to buy a PA and become the "guy with the PA"
     
    s0c9 likes this.
  6. CBBass123

    CBBass123

    Oct 18, 2005
    Texas
    I run sound professionally when I have the time. 12's are nice because they are lighter and a tad tighter. I have 2 PA systems. A full QSC and full JBL. My qsc is 2 k12.2 and 2 kw181 with a touchmix 16 mixer. This is my preferred system. I also have 2 jbl srx815p with 2 srx818sp subs. I prefer this setuo for DJ music.

    For small indoor gigs, the prx835 will be fine. They have to be laying on floor for greater bass response. Medium indoor or outdoor gigs its best to have main/sub. I've ran sound with the srx835p speakers and no subs for smaller gigs. They are my buddys speakers when he plays and i run the sound for him. Bigger gigs he adds srx728 subs.
     
  7. Wasnex

    Wasnex

    Dec 25, 2011
    A couple of things to consider. Using the Boost mode applies EQ to extend the frequency response a bit lower, but it does not change the amount of output that is available. I would not use Boost with live music as it basically creates an artificially smiley-faced EQ curve with hyped highs and lows.

    As @CBBass123 mentioned, speakers need to be ground stacked for max bass (half space loading). But main PA speaker need to be elevated above the crowd and ideally tilted forward to shoot the sound down into the crowd. If they are high enough you essentially consider them in full space instead of half space. At the very minimum, you will get low frequency boundary cancellation between the floor and the PRX835 where 1/4 wavelength is equal to the distance between the effective sound source and the floor.
     
  8. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    so it sounds like the more experienced answer is that the PRX835's will eventually require a sub to make them work in larger or outdoor situations. Sounds like I should keep focused on 2 way Mains and a Sub from a reputable manufacturer. I've heard very good things about the QSC's but I have also used and liked the EV EKX series boxes too .. and I have a decent discount for EV gear.

    Thanks for the replies on the larger 3 way boxes.

    Many of you who are running sound seem to be using multiple subs. Other than outdoor festival backlines (which can get quite elaborate) I have mostly seen bands use 2 way 12" or 15" mains and one (usually larger ... 18") sub (and of course multiple monitors). Seems to work well for smaller/medium gigs with moderate volume needs. Why so many subs ? are more of you playing at higher volumes or gigging heavier music styles that require a ton of low end support ?
     
  9. CBBass123

    CBBass123

    Oct 18, 2005
    Texas
    Not every gig needs 2 subs... but if its questionable, i usually run two because they are fairly lightweight... roll pretty easy and i always stack them. One main reason i like to run 2 is, if it is a questionable sized gig... i don't have to push 2 subs hard vs 1 sub.
     
  10. Wasnex

    Wasnex

    Dec 25, 2011
    You can always turn the subs down if two is too much. If one is not enough, your just plain out of luck.
     
  11. Samatza

    Samatza

    Apr 15, 2019
    Australia
    We use PRX 735's in a 300 seater room with no subs. I suppose it depends on the music you play and the levels you need but I actually prefer these without the sub. being a 3 way box they have a very smooth sound, near the back of the room the level is low but you would need a pair of speakers half way down on a delay to compensate.
     
    pfschim likes this.
  12. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    cool, thanks for that info. What kind of music are you doing ? I have 3 different bands that would be using this potential PA. Only one of them get particularly loud. Do you ever use the PRX735's outdoors with any success ?
     
  13. Samatza

    Samatza

    Apr 15, 2019
    Australia
    Our music ranges from jazz to Latin to funk but we’re not a loud band. Have not used these outdoors but I think they would struggle in a full band setting outside unless it’s a sort of confined audience area.
     
    pfschim likes this.
  14. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    M 6B393F4C-16A9-4D96-B931-4FC146078208.jpeg 835’s are kinda large for pole mounting. For safety and sonically I prefer having my 3 ways up on a sub, to 2 and short stick. Kw-153’s in my case. The 153’s will run away from k12’s volume and coverage wise. I've done Many shows on K12’s over 181’s and they are great up to a point. The 153’s will go way further. I would think the 835’s would do the same to 812’s.

    Pic above is in a high wind environment. The strap is actually keeping the 153 from rotating ... band is High Pulp from Seattle, WA. Very nice set of instrumental, synth heavy groove music.
     
    Wasnex and pfschim like this.
  15. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    I presume there was another 153 on the other side of the band ? another sub as well ?
     
  16. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    May 21, 2022

Share This Page