Introduction and Advice :)

[UK_SPAWN]

Hi all, I have come looking for a community of nice people who may be able to help and i hope i can return the favour too. I have been interested in audio for as long as i can remember and have always wanted to build a "seperates" system with custom parts.

im planning my system and i have some questions on how cartain things work.

1 component im looking at is the Behringer SUPER-X PRO CX3400 Crossover - I was just curious as to how it works and if its what i think it is?

the decive has 2 inputs (XLR) that i will run Phono/RCA unballanced XLR cables from my DAC (1 for Left 1 for Right) and the HIGH / MED / LOW outputs will go to seperate power-amplifiers and in turn to each driver in a speaker system (3-Way Bass-mid-high)

im assuming the device creates a Linkwitz-Riley crossover at the points you select on the dials? the reson its confusing me is that I also read that a "mid crossover" is like a "band pass" filter, but i dont understand how iset the start and end points for the mid band pass? - Thats why i assume the device works liike:

Low output handles everything BELOW what is set on the LOW DIAL. for bass?
the high handles everything ABOVE what is set on the HIGH DIAL. for tweeter?
so how does the mid work ..... lol im so confused?

if the mid works the same then that makes 4 distinct divisions ? so isnt that a 4way? i hope i make sense....

lets say i set LOW to 100Hz
and i set high to 4500hz

the bits between make up the "mid" .. so what does the mid do?...

im sure im over-complicating it a LOT..

Can anyone help me understand this
Thanks,

 

[UK_SPAWN]

i feel i didnt explain well still lol, in this picture you can see there are 2 cross over points, that creates 3 "areas" of "desired sound" shall we call it... so do i only need a 2-way crossover for a 3 speaker system?

http://sound.westhost.com/p09_fig2.gif

 

[TLS Guy]

i feel i didnt explain well still lol, in this picture you can see there are 2 cross over points, that creates 3 "areas" of "desired sound" shall we call it... so do i only need a 2-way crossover for a 3 speaker system?

http://sound.westhost.com/p09_fig2.gif

For a bass/mid/HF system you need a three way crossover. The instruction manual is here.

However if you use a device like this as a speaker crossover you are unlikely to get a flat response. A unit like this might be acceptable for PA systems, which is its intended use. However speaker drive units have roll off of varying and changing orders. The orders of the speaker roll off and electrical crossover roll off sum. So say you have a one speaker with a first order roll off around crossover and the other a second order roll off around crossover. Then you need a third order and a second order electrical crossover either side of the desired crossover point to get a fourth order crossover. This unit does not allow for that.

If you are think of building and active speaker you need to either design and build custom crossovers from scratch, know how to modify an existing crossover or use mini DSP. Mini DSP combined with REW is likely your best bet. I would start by building a two way first. Three way speakers are a much bigger nut to crack.

 

[UK_SPAWN]

What about running these for a crossoverless system, thats what i intended anyway. from amp straight to driver with the behringer doing the "splitting" - Or does a tweeter driver for example have its own crossover allready built in, say something from Monacor?

you lost me when you started talking about 1st 2nd order roll-off etc

I have figured it out now i think. i was over-complicating it a lot! - The mid output is whats left after you cut the Low and HIGH using the dials... you dont need a 3rd dial, thats for mono-4way!

And, thanks for the reply!

 

[UK_SPAWN]

EG - http://s33.postimg.org/z9ujqmedr/3way_system.jpg

 

[TLS Guy]

What about running these for a crossoverless system, thats what i intended anyway. from amp straight to driver with the behringer doing the "splitting"

you lost me when you started talking about 1st 2nd order roll-off etc
I have figured it out now i think. i was over-complicating it a lot! - The mid output is whats left after you cut the Low and HIGH using the dials... you dont need a 3rd dial, thats for mono-4way!

And, thanks for the reply!

What you intend is an active speaker. So the active crossover takes over the function of the passive crossover in a passive speaker. The crossover must still do the same job whether active or passive. It must blend the crossover regions as seamlessly as possible. This is not an off the shelf prospect.

If you don't understand orders, which is one of the most basic concepts to design a speaker, then you are a long way from ready to build yet.

Teaching someone how to design a speaker is not something that can be done on a forum like this.

Here is Linkwitz on crossovers.

Here is a basic article about crossovers.

It is vital to get the crossover right. The crossover more than anything else is the very heart of the speaker and determines more than pretty much anything else the quality of the speaker.

 

[UK_SPAWN]

So it would work without cusom making physical crossovers, connecting directly to the drivers. Im assuming i could also damage the tweeter for example setting it too low frequency x-over?

Thanks for the help so far, ill do some reading

 

[TLS Guy]

So it would work without cusom making physical crossovers, connecting directly to the drivers. Im assuming i could also damage the tweeter for example setting it too low frequency x-over?

Thanks for the help so far, ill do some reading

Yes, and you always run the tweeter though a cap so thumps do not damage the tweeter.

Well, yes it would work, but unless you are lucky it won't sound very good. All crossovers for high quality audio have to be custom.

Take a look at the Mini DSP I linked. If you are serious about this, that is what you need and not the Behringer. With REW, which you can download free, you can customize the crossover with the use of the software and omni mic.

Let me ask you this do you know how to design the loading of the bass drivers? Are you familiar with the different types of bass loading?

Another crucial issue is driver selection. You can't just order any old driver. You have to have enough skill and experience to look at the acoustic responses of the drivers and see which are contenders that will work well together. If you just order any driver you feel like without attending to this issue, far more likely than not you have have a design that is a non starter before you start.

 

[UK_SPAWN]

those are all things I will be asking about when i come to making the speakers (or modifying some). Ill ask for help selecting drivers and building the minimal neccesary protection for drivers while trying to leave as much of the X-over down to the behringer or just from my PC.

I already use roomEQ with a Pioneer Calibration MIC that came with an old reciever.. its not calibrated with a file and isn't perfectly flat, i calibrated it by ear using many refrence things (bic lighter at 1cm, coughing at 1m etc etc..) but it wasn't an issue for reading the freqency responses etc comparing them to online ones (i was within 1db to the online chart) - so i can use that program quite well now! its a good program.

As for the DSP i dont really need that as i have all those things on my computer anyway. I can set crossovers, delays, preamp, filters and EQs etc to any device output by the PC so all i need is a DAC and some amps. The reason i want the behringer is for analog control and just to play with really, it will be added later to the system. All i was really looking for is "yes that will work" or no it wont, as for the how it sounds bit... i think a system like that would be very tunable for exactly what sound you want in what driver.

Thanks for the input and im sure ill be back at some point to ask more random stupid things

 

[TLS Guy]

those are all things I will be asking about when i come to making the speakers (or modifying some). Ill ask for help selecting drivers and building the minimal neccesary protection for drivers while trying to leave as much of the X-over down to the behringer or just from my PC.

I already use roomEQ with a Pioneer Calibration MIC that came with an old reciever.. its not calibrated with a file and isn't perfectly flat, i calibrated it by ear using many refrence things (bic lighter at 1cm, coughing at 1m etc etc..) but it wasn't an issue for reading the freqency responses etc comparing them to online ones (i was within 1db to the online chart) - so i can use that program quite well now! its a good program.

As for the DSP i dont really need that as i have all those things on my computer anyway. I can set crossovers, delays, preamp, filters and EQs etc to any device output by the PC so all i need is a DAC and some amps. The reason i want the behringer is for analog control and just to play with really, it will be added later to the system. All i was really looking for is "yes that will work" or no it wont, as for the how it sounds bit... i think a system like that would be very tunable for exactly what sound you want in what driver.

Thanks for the input and im sure ill be back at some point to ask more random stupid things

I'm done with you. You don't have a clue and have learned nothing. You can not Eq a bad speaker. You HAVE to start with a good speaker. You need a proper crossover, active or passive. You do not cobble something together and then think you can Eq it from a PC. That is just Red Neck engineering.

 

[UK_SPAWN]

What bad speaker? i dont have a speaker yet? i seem to be annoying you through lack of knowledge and so i wont ask any more.

 

[UK_SPAWN]

Is anyone (else) using active crossovers here that knows what drivers may be good for this redneck system. I like the look of Kevlar and woven drivers or metallic looking ones.

I want to look at about <£100 for a 6" or 8" Woofer that will cover my "bass"
the same price or cheaper for a mid and a tweeter thats on par and not too expensive.

Looking for response between ~50hz and ~21khz.

I suppose not all the drivers have to be the same material unless thats important when building active system, and is seperate boxes "better" than all-in-one enclosure for an active x-over?

Thank you and sorry if im asking the wrong questions im new to this (as you can tell)

 

[TLS Guy]

What bad speaker? i dont have a speaker yet? i seem to be annoying you through lack of knowledge and so i wont ask any more.

No, your problem is you do not take advice. You admit you know nothing, but insist you know how to build an active three way speaker, which is a monumental technical challenge.

The fact is you are a lousy student and time waster.

I know you don't have a bad speaker now, but unless you have an attitude adjustment you will for certain.

 

[UK_SPAWN]

I do not want advice on how to not do it, or whats better in your opinion i just wanted advice how to set it up, but if thats beyond you, then dont worry about it, ill wait for someone else to come and help or try elswhere online its really no biggie... i have not purchased a single component yet or settled on any speakers or drivers. so how you know its going to "sound bad" i dont know... and im the one with the attitude? i already know who im dealing with, you an elitist "if its not this way its not right and it must be "perfect""

So instead of goin' off on a rant with your ego, why dont you reccomend me some drivers if you know so much what you are talking about! Geez.......

And i am listeniong and reading about what you say, but you cant expect me to know nothing to knowing everything after reading some stuff for 2 days... i dont know about you but it takes me longer than that to learn a whole new subject with terminology that you dont normally use... bear with me....

 

[UK_SPAWN]

Speakers from Zu have no corossover? hmm...

so i could use those not build...

 

[UK_SPAWN]

The link you posted to LW says to me that i SHOULD go for an active system...

"I have a strong preference for line level active dividing networks ahead of the power amplifiers (Ref. 2, 12, 17). In this approach the power amplifier output is connected directly - except for a very low resistance speaker cable - to the voice coil of the driver. The amplifier takes maximum control over the motion of the speaker cone which gives a greater sense of clarity and dynamism compared to a passive dividing network between amplifier and driver. Active crossovers make much more effective use of amplifier power. A clipping woofer amplifier is not seen by the tweeter, which has its own amplifier. The clipping of the woofer amplifier may not even be noticed in this case. It would surely be heard with a passive crossover, where it might even overheat and damage the tweeter, because of the large amount of high frequency energy in the clipped signal."

 

[UK_SPAWN]

SO, with the crossover "orders" is that a choice you make, or something you discover along the way or plan before you buy drivers? i understand the -3dB, -6 etc but dont understand why/how you would use different orders... if 2 speakers playing the same sound = +3dB then why would you use anything else but -3 crossover?, why use a -6 the you would have a -3 at the crossover... but i dont understand "summed"...maybe thats why

Anyone simplify that for me,

Thanks all,
And thanks TLS, i dont mean to be a pain, sorry... i just like to do things the way i planned... i looked into the mini dsp... i want analog control, can you think of anything "better" than the behringer for analog control of X-over. (i iknow you disagree with me but does that mean you cant help me learn to make my own mistakes and learn from them?)

Apreciate it
Mark