Digital Crossover Necessity

[Traijin]

I had the beginnings of this thread over in the Jack Pages. It is more appropriate here.

I have a pair of Jack 15's w/kappalite 3015's and straight array piezos for DJ PA's. I just like to host large parties, I am not a professional DJ nor do I have interest in being so. That being said, the Jacks are excellent. I have never thought volume levels like this would be achievable. For indoors I can get by with just the Jacks. I would like the option of more bass outdoors. My intent is a pair of Tuba 30's.

I reviewed the Tuba designs and see that they are not meant to have an on board crossover/filter like the Jacks or the SLA's I have built. Understandable, given the single sub and no other speaker ranges.

This topic was hit upon already and I do not wish to beat a dead horse, but I do feel the need to understand why something must take place. I was told in previous threads that a crossover is absolutely necessary for this setup. A DCX2496 to be precise. The cheapest I can find a new unit is 250.00. I would also need RCA to XLR and XLR male/female cables for everything to work.

I currently have a Crown XLR 2000 Amp for the Jacks. I asked why I wouldn't just get another amp and program it with the filtering I want for the subs? I was told is was just not the right way to do it. Okay, I hear you and trust the advice, but I need to know why. From what I have read, a 3rd order butterworth is a basic but very effective circuit from crossing over a signal. But I am in effect talking about filtering out the highs of a signal. Something would have to heat sink the unused signal. Is the cascading multiple butterworth design in the DCX much better at this? Is this cascading crossover needed to develop the signal slope that works best for the subs? Why is it so much better than the amp filter? Isn't this a reason why people spend the money to get a crown amp? I am reading as much as I can, but I would like some help in understanding.

Thanks

[RubiconProSound]

There are plenty of other options for crossovers aside from the Behringer DCX... I still run a basic dBX 223xl crossover in one of my racks.

You could always just go with a basic crossover like the Behringer CX2310 for $80. Based on your comments, It will be plenty adequate for your needs.

I just like to host large parties, I am not a professional DJ nor do I have interest in being so.

If you still want more capability than a basic crossover try the BBE DS24 which can be found brand new online for $189. It has similar features to the the DCX and gets good reviews from the folks over at DJForums.com


Behringer CX2310
http://www.behringer.com/EN/Products/CX2310.aspx

BBE DS24:
http://www.bbesound.com/products/speake ... /ds24.aspx


In regard to the "WHY" of not just running another XLS and using the onboard crossover:

Generally for subs you want to use a high pass (also known as a "low cut") in conjunction with the low pass. An average setup would be a high pass at 40 Hz and a low pass at 100 Hz. This means the subs are only getting the frequencies between 40 and 100 hertz. Using the Low Cut on the crossover will protect the woofers. Pushing subs beyond their low frequency cutoff is a bad thing and can damage them.

I don't own an XLS amp and could be wrong... but If memory serves correct, the XLS series amps don't have a "low-cut" capability, you can only set the crossover for High or Low, but not two at the same time on a given channel. This is why folks are advising against just using the on-board x-over.

[Bill Fitzmaurice]

Something would have to heat sink the unused signal.

There is no unused signal to heatsink. An active crossover routs the split bandwidths to the appropriate amp. A passive crossover routs the split bandwidths to the appropriate drivers.

I currently have a Crown XLR 2000 Amp for the Jacks. I asked why I wouldn't just get another amp and program it with the filtering I want for the subs?

So long as both amps have programmable filters there's no reason not to.

[Traijin]

Wow, this is a great board. I get to learn new things everyday.

Thanks for the input! I feel like Johnny 5.

Seriously folks, I try to ask thought out questions and I get good answers. Thanks!

[Bruce Weldy]

Are you using a Crown XLS or Xti? There is no XLR.

I'm assuming an XLS. That amp should be able to run the Jacks on one side and the Tubas on the other. The onboard crossover doesn't have the ability to hipass and lopass on one channel, but if this is just for outdoor parties and you don't get carried away with the volume on the subs - you'll be fine. It'll give you 325 watts per speaker in this set up, so there should be plenty of power depending on which speakers you use in the subs.

So, bottom line is, if you are careful with volume - you already have what you need...just build some subs.

[Traijin]

Are you using a Crown XLS or Xti? There is no XLR.

So many Letters, It is XLS, getting confused with speaker cables... go figure

[Bruce Weldy]

Are you using a Crown XLS or Xti? There is no XLR.

So many Letters, It is XLS, getting confused with speaker cables... go figure

Now to really ruin your day.....XLRs are used on mic/line cables, not speaker cables

Hang in there - it all gets easier.

[Traijin]

Far from ruining my day, it proves my point precisely... A of confusing jargon to keep straight.

[Bruce Weldy]

Far from ruining my day, it proves my point precisely... A of confusing jargon to keep straight.

Sound is pretty easy .... I sold Car Dealership Computer systems where we had over a hundred 3-letter acronyms to deal with for our software alone....not counting all the manufacturer 3-letter acronyms for their products and programs.

[SeisTres]

If you're not doing this for money and is really not all that critical, you could get a minidsp (google it and i'll come up) and just run subs off one of the channels and tops off the other. However, with that xls, you won't be getting max volume anytime but it'll do, no big deal there. The mini dsp has eq and crossover.

Just be careful with that xls as they tend to thermal (shut off due to overheating) if you drive them hard. My 402 thermalled about 3 times and even my 802 did this one time and I only had four titans on it.

[Bruce Weldy]

Just be careful with that xls as they tend to thermal (shut off due to overheating) if you drive them hard. My 402 thermalled about 3 times and even my 802 did this one time and I only had four titans on it.

His XLS2000 is one of the new drivecore amps. Totally different than the original XLS series that end in x02.

I've got three of them and never had one overheat including outdoor summer gigs.

[Traijin]

Okay, so Lets say I pick up a DCX and maybe even a DEQ. At first I want to run one amp channel to the jacks and one to the tubas. My music setup is on a table with the cabs to the left and right. To wire the two cabs per channel I would run a speakon to a cab and daisy chain to the other cab? It is a lot more cable than what I really should need. Is there a splitter cable or block so the signal can be split at the amp?

[jswingchun]

Okay, so Lets say I pick up a DCX and maybe even a DEQ. At first I want to run one amp channel to the jacks and one to the tubas. My music setup is on a table with the cabs to the left and right. To wire the two cabs per channel I would run a speakon to a cab and daisy chain to the other cab? It is a lot more cable than what I really should need. Is there a splitter cable or block so the signal can be split at the amp?

How about this:

http://billfitzmaurice.info/forum/viewt ... =14&t=7609

[Traijin]

I had read that post, it seemed like that solution was for different speaker cable types. I'm sure I could wire it to act as a splitter, is it a common solution?

[Bruce Weldy]

Okay, so Lets say I pick up a DCX and maybe even a DEQ. At first I want to run one amp channel to the jacks and one to the tubas. My music setup is on a table with the cabs to the left and right. To wire the two cabs per channel I would run a speakon to a cab and daisy chain to the other cab? It is a lot more cable than what I really should need. Is there a splitter cable or block so the signal can be split at the amp?

Position the amp closer to one side, use a shorter cable for that side and a longer one to daisy chain to the other. There are a lot of other ways to skin this cat, but they'll be more expensive or jury-rigged. Just build one shorter cable and one longer cable. Don't make it harder than it is.