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Bi-Amping the Carvin LS 1503

Discussion in 'Amps and Cabs [BG]' started by jnewmark, Dec 26, 2011.


  1. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Has anyone ever done this with their Carvin LS1503 cab ? Now that I use the BX1500, which is bi-amp capable, I'm kinda curious as to how it would sound as compared to full range? Also, not real sure how to wire the speakons. The manual gives a wiring description for bi amping, but it sounds like they are describing how to wire it up for one speakon only. I clearly need to use two speakons with the BX1500, so I'm kinda puzzled about this. Any help or comments ?
     
  2. jeff7bass

    jeff7bass

    Apr 9, 2009
    The Carvin BX1500, when paired with a single cab, is like any other full-range amp. If you run it in bridge mode as compared to bi-amp mode, you'll just be pushing the single cab with more power. I wouldn't recommend running the two amps bridged into that one cab because you might destroy it.

    The benefit of Carvin's style of bi-amping is that you can drive two cabs with different volume, different resistance and different speaker configurations while avoiding some of the pratfalls of using a single amp. Say like an 18" sub paired with a 410. In bi-amp mode, one can be 4 ohms and one can be 8 ohms and since you have a separate amp (and VOLUME knob) for each cab, you can adjust each cab's volume yourself.

    Great feature for different rooms, stages, etc...
    The Crossover knob, active only in bi-amp mode, lets you assign which frequencies are directed to which cab, making more effcient use of the speakers.

    So it's not a bi-amp type of amp which has an amp for the mid-range/tweeter and another for the woofer, it's more like an active crossover unit built into a PA system for directing lows to a sub and mids/highs to a 112/horn cabinet.
     
  3. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Hmm, not getting this at all. The BX1500 can be used to bi amp, and with the variable crossover, can be used to do exactly what you describe, you don't need two different cabs, just a 3 way capable cab, like, the LS1503, which is bi amp capable - it has a switch on the back to allow this function. One amp on the BX1500 would go to the lows, ( the 15 ), the other would go to the mids and highs, ( the 6" and tweet ), with a crossover set on the amp to whatever frequency.
     
  4. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    You can either build a breakout box or a cable with two Speakons on the amp end and one approriately wired 4-pole one on the cab side.
     
  5. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Yikes, not the dreaded " Y " cable !
     
  6. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Yep, 'fraid so. This is quite common in pro sound applications, and typically done on a back-mounted rack panel.
     
  7. will33

    will33

    May 22, 2006
    austin,tx
    Assuming the cab end has a 4 pole speakon and a switch for biamp mode rather than separate inputs for lows and highs, yes you'd need to make up a Y cable. 2 wire + and - (x2) on the amp end (1 lows and 1 highs) and a 4 wire on the cab end. Double check your cable wiring and test at very low volume the first time.
     
  8. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    So, the two speakons on the amp end are both wired the same / It does'nt make any difference as to which one goes to highs or lows ?
     
  9. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    It makes all the difference in the world; read the manual three times and then test at extremely low levels. Be sure to label everything really well -- I like to use color coding to keep things [DEL]Charlie[/DEL] idiot-proof.
     
  10. bluewine

    bluewine Banned

    Sep 4, 2008
    WI
    Does you're theory aply to GK bi- amping as well?

    I have a 2 10 & 1 15
    GK RBX cabs powered by an rb1001
     
  11. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Well, let's see. The manual for the LS1503 says: " Speakon pin configuration for biamping is : 1+ LF Positive / 1-LF Negative 2+ MF/HF Positive / 2-MF/HF Negative. That, I take it, is for the 4 pole, cab end speakon. How would the two amp side speakons be wired ?
     
  12. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Okay, I use a tri-amped system which includeds bi-amping two LS 1503's. Ther's two ways of doing this and I chose the harder of the two to incorporate a medium size amp (450 watts / side) for the 15" driver and lower power amp (275 watts / side) for the mid driver and horn. To avoid having two Speakon connectors hanging on the amp-end of the cables, I built a speaker patch bay from a universal rack plate I found on partsexpress.com.

    PatchBayFront-1.

    I use 13 g four-conductor cable with all four leads wired to Speakon cable ends. +1, -1 carries the mid signal while +2, -2 carries the high freq. signal. Be sure and reconfigure the LS1503'S switch for bi-amp mode. The new speaker output (there are two) on the universal patch bay takes a feed from both the mid amp and HF amp. Here's a pic of the reverse where you can see two separate speaker cables connected with crimped quick connect terminal ends (far right):

    PatchBayRear-1.

    The amp-end of the cables are essentially a permanent install so I used "U" terminal ends and slipped them sideways under the red & black binding posts (not pictured). If you look starting right > left, you'll see: left main bi-amp, right main biamp, subwoofer bridged mono, channel one monitor, channel two monitor. Neat, huh?

    Here's another method which is simpler: Many power amps carry both channel A's and channel B's ouput signal on channel A's ouput when using a properly wired 4 conductor cable. Here's what you do:

    *Feed your Xover's mid signal to channel A of the amp.
    *Feed your Xover's HF signal to channel B.
    *Attach the 4 conductor Speakon cable to channel A's output and LS1503
    *Adust your power amp attenuators and Xover levels judiciously so you don't blow out the HF drivers.

    From the looks of things, you have no choice but to use a single 4 pole Speakon on the LS1503 side and two hanging off the amp end...one wired +1, -1 for the mids, the other +2, -2 for the HF's. Use plenty of extra strain relief as a good ~6" will be missing the outer insulating jacket.

    Riis
     
  13. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Wow! All I can say is thanks for taking the time to post that, but, way more complicated than I want to get. Anyways, the BX1500 does not sum both channels into one, AFAIK, like my QSC power amp does, so it looks like the dreaded Y cable will have to do. So, how does the LS1503 sound bi amped as compared to full range ?
     
  14. Johnny.....You'll need a four conductor cable, one four conductor Speakon (for the cab end), and two plugs (either Speakon or 1'4") for the amp sends. Just make sure you are consistant with your wires. ie; red & white for the lo freq, and green & black for the hi freq.
    Set your active xover around 500Hz, lower the volumes, and experiment from there. :cool:

    edit; I built one one with two 1/4" plugs to use with my 800RB (which I sold). I'd send it to you if I could find it in my warehouse, but that would be a month long feat! :help:
     
  15. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Sorry for the overkill but my holiday-induced sugar buzz put my brain into OD. All you need is a 4 conductor cable and (3) Speakons to pull it off. I have the remnants on a spool and can procure the Speakons if you'd like me to fabricate one for you....glad to do it for the cost of the components and shipping but a 5' cable would run ~$25 when all is said and done.

    I have heard no discernible difference or improvement but my bandmates have made positive comments. Either way, projects like this are tons 'o fun.

    Riis
     
  16. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.
    Hey Eric, I was hoping you might chime in. I thought you might have mentioned doing this at one time with your LS1503. Looks like a Y cable would do the job. Probably not gonna sound much different, but, I thought maybe fooling around with crossover freqs might change things a bit to my ears. Hope things are looking up for you 'bro.
     
  17. derrico1

    derrico1 Supporting Member

    Apr 12, 2005
    Charlottesville, VA
    I've run my 1503 bi-amped this way, but there was no appreciable difference in a band setting.
     
  18. jnewmark

    jnewmark Just wanna play the groove. Supporting Member

    Aug 31, 2006
    Stax 1966
    Third St. Cigar Records staff musician.

    Did you play around with the crossover point ?
     
  19. babebambi

    babebambi

    Jan 7, 2008
    YTZ
    I had pretty good result bi-amping my WT800 into the LS1503, and liked the way it sounded better than when bridging. Bi-amping sounded cleaner. Also being able to adjust cross-over point and High/Low balance is appealing to me.

    In the end, it comes down to which cross-over (the passive in your cab, or the active in your amp) sound better to your ear.
     
  20. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    The crossover point is 500 hz but I've seen one reference suggesting that 630 hz is more suitable. I can neither confirm nor deny.

    Riis
     

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