Karaoke Forums

All,
I am starting to look at subwoofers, and am curious about the crossover. If I bought an amp, and a sub what do I use to crossover the low frequencies? On car audio, there is a choke you can buy that will crossover for you, but do subs have crossovers built in or? Thank you very much!

Blackrose,
  You have some options...  Most subs have the crossover built in but with no way to adjust them... Some have maybe two crossover settings like my carvin 1801s.  I use carvin mains and then sound fine using the internal crossovers. I do it that way just to simplify my gear although I have been eyeing a DriveRack this holiday season.

  The technical best way is to have a good controller to really tweak the crossover points.  I think most people end up going with the same brand speacker as the Markitecture(Marketing Technical Archtecture) says they are matched.  Hopefully Lonman can expand on what it really means to be matched, especially since the mains are engineered to handle bass without a sub...  Could a mixed Yamaha and JBL or Carin and Yorkville system really sound bad given a good signal, mix, and amp...  Probably not..

I have seen some folks with mismatched sets that sound good to me as well.

What kind of mains, mixer, amp do you have now?

Best Regards
Big Bob

What is your system comprised of right now?

Generally you want to match your sub to your mains - same series, but you can yield good results if they aren't.  Many - not all, depends on the make & model - subs have a built in 'high pass filter' which means the sub gets all the sub frequencies it's supposed to & nothing else then sends the rest of the frequencies out to your mains using the high pass output - this would only require 1 amp, however connecting a sub & satellite to the same amp drops the impedence & you need to make sure the amp has enough power to push both the subs & satellites - subs are power hungry.  Sometimes the filters are adjustable, most of the time they are set at fixed frequencies - if they have one at all.  
Using an external 'active' crossover such as the dbx 223XL, you would need 2 amps, 1 for the subs & 1 for the tops - not only yields the best sound quality, it's more efficient & allows each amp to push their own speaker.  This would bypass the need for any internal crossove built into the sub as it would be done externally & give you more flexability in tailoring your sound in different rooms.  The low sub outputs on the crossover would go to the sub amp - then to the sub & the high pass outputs on the crossover will go to the high output to the tops.  Most subs should be crossed over anywhere from 75-120hz for the best results, but the manufacturer will have recommended frequenc points that will be a good starting point.

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I have a Yamaha EMX512 powered mixer pushing 2 yamaha br12's. I am thinking of going one of two ways, but I need more bass either way. I was looking at a used set of peavey 18's in a box the model is something like 2118 bx?? Also, I was looking at the single peavey in the box. So I would need to know what kind of amp to buy for these. I also looked at the jbl jrx118. They have a powered version as well. So i am either going for a powered sub to connect to my mixer outs or getting another amp and connecting a sub to it. Hrm... decisions, decisions...

Blackrose,
   I would try a good pair of Subs with a built in crossover 1st with your current amp.  Is it the EMX512SC with 2-500 watt outputs?  You will be surprised how much of a fuller sound you get amd the bass difference will be huge.  That may be enough depending on how picky your ear is...  If you are not happy with it then you can always add another amp and crossover.  I usally take the add in increments approach...
Best Regards,
Bob

That is the correct amp. I did not know it was 500 per channel, I thought it was 500 total. I will have to look. I have 2 br12's that run out of left and right. If I run them in parrallel and then run a sub out of the other channel this will be ok? Could you recommend a sub that would work? Thank you.

Blackrose,
   Acutally you would run them the same way you do now.  Most subs have a 1/4 inch in and out. You would run your left channel into the left sub and then connect from the sub to the left main(Daisy chain).  Same thing for the ride side, into the sub then into the main.

Depending on the sub, like Lonman said you will have a full range output or  crossover at a certain frequency.  On mine it is a small recessed button.

As far as recommendations on a sub the 1st challenge is 15inch or 18s.  There was good thread here a while back on sub size.   I went with 18's and have been very happy. Some folks prefer the tighter response of a 15 inch.  The 18s can also require more juice to drive.  

Asfar as specific subs I would ask the group to pitch in.  I love my Carvin 1801s, they have great response and tremendous output.  The disadvantage is that are heavy.   I have worked with JBLs, PV 118s and Gemini's.  The JBLs and peaveys where comparable to the Carvins, the Gemini's were not as crisp.   There are also some smaller subs out on the market but I have not used them in one of my setups.

I would get some to these folks to shed some light on there hands on experience with Yamaha Subs like the A15W 15" since you are already using the br12's and some of the subs from Yorkville, Carvin, Peavey, Behringers, and JBL .  Just make sure they have the built in crossover.  I would narrow down from there.   Especially if you already have a brand preference that sounds good to your ear...

I have to admit I am very interested to hear any feedback from folks who have tried a molded plastic sub like the 42 lbs. Peavey PR-15.  I could not reccomended it, as I have never heard it in action or used it in  my rig, but it is 30 lbs lighter than my Carvins...

Best Regards.
Bob

Wow! Thank you for the great advice. I do not need it to be rocking to hard, but 2 15 inch subs would probably do really well. I imagine the lower wattage subs would work? I really appreciate your inputs guys!

What if I were to connect the 2 sattelites to one channel and feed the 500w into a sub on the other channel or am I looking at this wrong. Thank you again.

As answered in your other post, you would be underpowering your mains if you daisy chained them onto one side of the amp. It can be done, but you are going to lose power and quality by doing it and may endanger your speakers and amp.

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C Mc
KJ, FL

You are right, I forgot that was in another post ! Thank you.