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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB: The Classic Live Audio Board => Topic started by: Adam York on September 02, 2012, 01:08:42 AM

Title: Adding an internal X-over to Yamaha CW118V
Post by: Adam York on September 02, 2012, 01:08:42 AM
Can anyone tell me what I can do to be able to run one cable from my amplifier to a Yamaha Club Series 18" subwoofer and jump from the sub to a full range cabinet? Is there some kind of crossover capacitor that I can wire to the subwoofer inputs that will separate the lows and highs? I previously had a pair of Behringer B1800X Pro subs that had the crossover built in to the sub and was able to jump from the sub to the top. I am currently using an external crossover and running one speaker cable to the sub and one to the top, this work great, but it would be nice to use less cables and would make setup and tear down a little quicker. Any help would be greatly appreciated. Thanks.
Title: Re: Adding an internal X-over to Yamaha CW118V
Post by: Jared Bartimus on September 02, 2012, 04:44:51 AM
Can anyone tell me what I can do to be able to run one cable from my amplifier to a Yamaha Club Series 18" subwoofer and jump from the sub to a full range cabinet? Is there some kind of crossover capacitor that I can wire to the subwoofer inputs that will separate the lows and highs? I previously had a pair of Behringer B1800X Pro subs that had the crossover built in to the sub and was able to jump from the sub to the top. I am currently using an external crossover and running one speaker cable to the sub and one to the top, this work great, but it would be nice to use less cables and would make setup and tear down a little quicker. Any help would be greatly appreciated. Thanks.

One option if you just want quicker setup/teardown and fewer cable runs would be to get a 4 conductor speaker cable and rewire either your tops or subs to be connected to +2/-2.  Then you could still just run a jumper between the two.  Most amps with speakon outputs connect one of the speakon connectors to both +1/-1 and +2/-2, or you could build a small patch panel for around $20-$30 assuming you only used it for speakons and not all your connectors.
Title: Re: Adding an internal X-over to Yamaha CW118V
Post by: Mark McFarlane on September 02, 2012, 10:05:46 AM
Can anyone tell me what I can do to be able to run one cable from my amplifier to a Yamaha Club Series 18" subwoofer and jump from the sub to a full range cabinet? Is there some kind of crossover capacitor that I can wire to the subwoofer inputs that will separate the lows and highs? I previously had a pair of Behringer B1800X Pro subs that had the crossover built in to the sub and was able to jump from the sub to the top. I am currently using an external crossover and running one speaker cable to the sub and one to the top, this work great, but it would be nice to use less cables and would make setup and tear down a little quicker. Any help would be greatly appreciated. Thanks.

It's not quite as simple as adding a capacitor to the speaker line.  You should, ideally, low pass the sub and high pass the tops.  Thats 2 separate circuits that involve multiple components (multiple caps, inductors, and resistors) in each circuit.  The ratings and topology of the components need to match your desired frequency response and power handling capacity.  You can find many references on the Internet for designing such circuits, but note that a typical home hi-fi crossover won't handle the power levels of a live sound setup, the components will melt.

You can also buy pre-made crossovers ready for cabinet mounting.

The easiest solution was already specified, make some custom cables using either Speakon jacks/plugs, or just make a speaker snake with 2 appropriate jacks on each end but that have a single wire bundle to run from your amps to speakers.  Depending on how your amp(s) are connected to the speakers, you may be able to use 3-wire cable, or perhaps a safer alternative that will handle multiple amp-speaker connection setups is to use 4-wire cable.

Another option is to take apart your current crossover and put 1/2 of the circuitry in each sub cabinet and add jacks for 'full range' out and 'high passed out',....

If you don't already have Speakon jacks on all of your speakers and amps, I'd just go to Home Depot and buy some 4-wire cable.
Title: Re: Adding an internal X-over to Yamaha CW118V
Post by: Tom Young on September 02, 2012, 11:25:47 AM
It's not quite as simple as adding a capacitor to the speaker line.  You should, ideally, low pass the sub and high pass the tops.  Thats 2 separate circuits that involve multiple components (multiple caps, inductors, and resistors) in each circuit.

A few clarifications:

a 6dB-per-octave low pass filter for a subwoofer would consist of a coil (and a large one at that). A 12dB-per-octave low-pass filter would consist of a coil and a capacitor. If you used a real crossover (with low-pass and high-pass outputs) you now need (2) coils and (2) capacitors.

If done correctly, these parts would be specific values based on the crossover frequency itself plus the impedance of the subwoofer and the fullrange box above. You also have to address the relative levels of the subs versus the fullrange. No easy task.

Finally; if you eally want to "treat your speakers right" you will add a high-pass filter to the subwoofer to protect it from over-excursion below the port-tuning frequency.

(maybe you're better off with what you have)
Title: Re: Adding an internal X-over to Yamaha CW118V
Post by: Mac Kerr on September 02, 2012, 11:36:55 AM
Can anyone tell me what I can do

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Mac