Crossovers

[chris_gilly 0]

im thinking of buying a crossover for my system...

am i right in thinking it seperates the bass and top??

so you get a pure bass signal to one amp and the rest to another of does it just split the signal into two??

[Kingy 0]

It splits the signal into Bass & Top if it is a two way crossover.

 

What is your full set up??

[chris_gilly 0]

yes its a two way,

my setup is two 300watt each tops and two 600watt bins each

i have been running two amps one for each.

i have been using my balanced output for the tops and unbalanced for the bins

do i need a crossover??

[supersound dj 0]

just be careful how you set-split it as you might lose frequencies at the point of cross.

 

Paul

[chris_gilly 0]

just be careful how you set-split it as you might lose frequencies at the point of cross.

 

Paul

 

am i ok doing it the way i am or am i best getting a crossover as the one on ebay ive seen ends in an hour!!

[Bouncy Dancefloor 0]

also alot of "disco" bass speakers have a crossover built in already, so pretty pointless

 

need more details about your tops, but in a 4 box system, its common to just run them full range

[chris_gilly 0]

also alot of "disco" bass speakers have a crossover built in already, so pretty pointless

 

need more details about your tops, but in a 4 box system, its common to just run them full range

 

 

my bins do but my tops tend to sound echo'y under bass like there trying to do bass its sounds real dodgy!

 

im running a pretty much budget system

my tops are two soundlab p115bp 300watt

my bassbins are 600 skytec

and im running a sp500 amp and an sp250 amp (soundlab)

with a gemini platinum series mixer.

 

im hoping to make tweeter boxes to soon.

[TonyB 0]

As you have two amps already, I would get the active crossover if it goes cheap enough.

[chris_gilly 0]

As you have two amps already, I would get the active crossover if it goes cheap enough.

 

ok thanks

[Danno13 0]

It would be an advantage to have an active crossover, as the amps will perform better when working with a narrower band of frequencies, as will the speakers.

 

If you change the wiring in the bass bins, so that the input bypasses the passive crossover then you'll also get more from the bins as the internal crossover won't be using up amp power.

[Andy Goodtimes 0]

An active cross-over will help but I suspect that the system is badly matched so it won't be perfect.

 

I'm guessing your tops are 150w per cab so if the amp is 250 then I assume its 125 going to each cab so that's already underpowered before you think about the impedence...assuming the cabs are 8 ohms then the amp might only be producing about 80w for each cab. If the bins are 300w each and the amp is 500w giving you 250w per channel you are already underpowered but if the bins are 8ohms then it could be that each bin is only getting about 160 so once again badly underpowered, you could in effect have 900w of speaker power and only about 480w of amp power...idealy to run 900w of speakers I would be looking for about 1,100w of amp power.

 

I am just generalising as I am not familiar with your specific speakers and amps, but anyway a cross-over will help as its ensuring that each cab will only be trying to reproduce what its best at thus not waisting power. And, as Danno says make sure you also aren't employing a passive cross-over inside the bin housing as that's a drain on power too.

 

Just generalising again as I don't know your system but setting the cross-over point somewhere between 150-200hz should be about right.

[Bouncy Dancefloor 0]

as ive had many of the skytec speakers put in front of me (and people expecting me to repair them lol).I wouldnt dare put the actual wattages into the speakers, at this sort of level its often better to stay under the wattages, then you know to turn it down when the red lights flash! If you get a decent power amp onto these speakers, they WILL blow and youll end up putting them in a skip

[supersound dj 0]

another way to avoid the muddy bass is to run them full range but run the tops out of phase.

[norty303 0]

another way to avoid the muddy bass is to run them full range but run the tops out of phase.

 

Well yes, it'll avoid the muddy bass because its a really effective way of killing the bass frequencies dead! Given all of the phase checking tools on the market, generally most sound companies do their best to avoid reversed polarity drivers.

[Kingy 0]

Well yes, it'll avoid the muddy bass because its a really effective way of killing the bass frequencies dead! Given all of the phase checking tools on the market, generally most sound companies do their best to avoid reversed polarity drivers.

 

Totally agree, this is not the best way to do it.

[RichardP 0]

Just to add another question to this discussion, does anyone know of reasonable quality passive crossovers that can be added to a bass bin, for units that don't have their own passive crossover?

 

Or maybe, can anyone point me to a reference where I could consider building my own quality passive unit (and still be able to experiment with optimum crossover point)?

 

I would expect PA purists to say that active for is generally/always the way to go - but there are situations where I would quite like to slightly augment a pair of 12"+1" tops with an 18" sub, but without the additional bulky overheads of a 2nd amp & active x-over.

 

 

Thanks in advance...

 

Edited October 22, 2008 by RichardP

[norty303 0]

I think it depends on how powerful you want your sub to be.

 

Once you get over around 500w power handling the cost of a passive network becomes prohibitive compared to an active solution. If you want a passive solution at all costs then the sky is the limit, but at some point you might want to look at some of the dedicated 3 channel amps (or 4 channel with a pair bridged giving 2+1 channels) designed to do exactly this sort of thing, normally with built in DSP to do the filtering.

 

 

Eminence do a PX250 low pass filter for around £35 which might do the job, however 250hz is a bit high for a sub if you ask me, I'd be looking for something nearer the 150hz range.

 

BTW if you Google 'passive low pass filter' you'll get a variety of sites giving DIY solutions. If you come over and ask the question at www.speakerplans.com/forum I'm sure one of our members will be more than willing to guide you on your way.

Edited October 22, 2008 by norty303

[TonyB 0]

Passive crossovers can do awful things to the sound quality too! They can consume up to 20% of the power and affect the way the amplifier handles damping.

 

None of my bass bins have crossover, they have all been removed.

 

The other problem having one bass bin is with a stereo set up, you can only have it on one channel. One side will just have the full range speaker and the other a top and bin. Might sound ok :shrug:

[Andy Dunn 0]

I think it depends on how powerful you want your sub to be.

 

Once you get over around 500w power handling the cost of a passive network becomes prohibitive compared to an active solution. If you want a passive solution at all costs then the sky is the limit, but at some point you might want to look at some of the dedicated 3 channel amps (or 4 channel with a pair bridged giving 2+1 channels) designed to do exactly this sort of thing, normally with built in DSP to do the filtering.

Eminence do a PX250 low pass filter for around £35 which might do the job, however 250hz is a bit high for a sub if you ask me, I'd be looking for something nearer the 150hz range.

 

BTW if you Google 'passive low pass filter' you'll get a variety of sites giving DIY solutions. If you come over and ask the question at www.speakerplans.com/forum I'm sure one of our members will be more than willing to guide you on your way.

 

I'm sure Tony Andrews will be glad to hear you say that 250hz is too high to crossover from bins to mid-hi packs,as thats exactly where the Turbosound TSE series of concert cabs did x-over.

 

And they sounded pretty good I think you'll find

 

:bouncy:

 

I really must learn how to do this getting the right piece of quote thing!!! tongue out icon

[RichardP 0]

Thanks for the info & tips there, chaps.

[Kingy 0]

Surely the crossover points depend on the physical charecteristics of the driver and type of cab involved.

 

When I had 18" subs prior to going exclusively active, they were crossed at 150hz. I used a C-audio RA 3001 to drive them. Happy days!!

[Andy Dunn 0]

Horses for courses as you say !

Just another thing to add to the mix,obviously you need to match the bins to the mid-hi packs otherwise you will lose a lot of frequencies somewhere in the mix!

[norty303 0]

I'm sure Tony Andrews will be glad to hear you say that 250hz is too high to crossover from bins to mid-hi packs,as thats exactly where the Turbosound TSE series of concert cabs did x-over

 

Oh ok, we'll compare every generic reflex speaker against a well designed horn setup with well researched characteristics running actively then. :)

 

Most cheap 18" reflex bass bins are not designed to produce low mids well as it requires a lighter cone structure. The manufacturers tend to go for boom by using a heavier one, and something gets sacrificed. Using a 15" mid (or a decent 12") you are better having the kick region in the faster cone. Due to the high excursions in bass bins/subs, the narrower the bandwidth the better i find for sound quality.

 

The Turbo gets this by being a horn which tend to have better dynamics in this respect. That said you'll need a few of the TSE's to get as low as the reflex will do in singles or pairs. The horn path and mouth aren't big enough in singles to do the job.

Edited October 23, 2008 by norty303

[Kingy 0]

 

The Turbo gets this by being a horn which tend to have better dynamics in this respect. That said you'll need a few of the TSE's to get as low as the reflex will do in singles or pairs. The horn path and mouth aren't big enough in singles to do the job.

 

Which I bet everyone already knew and understood.... tongue out icon

[supersound dj 0]

Oh ok, we'll compare every generic reflex speaker against a well designed horn setup with well researched characteristics running actively then. :)

 

Most cheap 18" reflex bass bins are not designed to produce low mids well as it requires a lighter cone structure. The manufacturers tend to go for boom by using a heavier one, and something gets sacrificed. Using a 15" mid (or a decent 12") you are better having the kick region in the faster cone. Due to the high excursions in bass bins/subs, the narrower the bandwidth the better i find for sound quality.

 

The Turbo gets this by being a horn which tend to have better dynamics in this respect. That said you'll need a few of the TSE's to get as low as the reflex will do in singles or pairs. The horn path and mouth aren't big enough in singles to do the job.

 

 

The Rev will know n understand that.