Hi everyone I was just getting in to pro audio and i currently have system with 2 custom built 12 inch bass bins and 2 mid/high cabinets, I have behringer mixer, eq and behringer km1700 amplifier. But i currently only have one amp and i was wondering if i could build a cheap passive crossover for subwoofers and tops. I was thinking of making it a rack mount box with speakon inputs on the back and speakon outputs for subwoofers with low pass and outputs for the tops with high pass.
I already did some experiments since my speakers are 8 ohms and that behringer amplifier supports down to 4 i connected all the speakers in parallel and it actually didn't sound too bad. Biggest problem with that is that tops don't handle bass well. What do you think about this idea and can you give me some advice.
Thanks.
I already did some experiments since my speakers are 8 ohms and that behringer amplifier supports down to 4 i connected all the speakers in parallel and it actually didn't sound too bad. Biggest problem with that is that tops don't handle bass well. What do you think about this idea and can you give me some advice.
Thanks.
You could certainly (with advantage) use a mid/high pass filter with each of your mid/high cabinets.
This could be as simple as a single capacitor in series with each mid/high cabinet. It all depends on at which frequency you want to bring in the mid/high cabinets.
For example, a 100uF non-polar (NP) capacitor would bring them in above around 100Hz.
This could be as simple as a single capacitor in series with each mid/high cabinet. It all depends on at which frequency you want to bring in the mid/high cabinets.
For example, a 100uF non-polar (NP) capacitor would bring them in above around 100Hz.
Thanks for the fast reply.
Yes i was thinking the same and my subwoofers seem to have pretty natural rolloff at higher frequency but would it be a good idea to add low pass to subwoofer output just to not load amplifier with something that won't be heard.
And also i think that adding low pass would decrease heating of the subwoofer.
Yes i was thinking the same and my subwoofers seem to have pretty natural rolloff at higher frequency but would it be a good idea to add low pass to subwoofer output just to not load amplifier with something that won't be heard.
And also i think that adding low pass would decrease heating of the subwoofer.
There is no real need for a low pass filter due to the natural roll-off that you mention.
And, there is no danger of overloading the amplifier or overheating the subwoofer by not including one.
Nothing to stop you including one however!
And, there is no danger of overloading the amplifier or overheating the subwoofer by not including one.
Nothing to stop you including one however!
Just to add: The natural increase in the impedance of the sub-woofer with increasing frequency will act as its own low pass filter.
Plus, the inductor required for the low pass filter would be large and expensive (in the order of 22mH at 100Hz).
If purchasing the capacitor, make sure it is non-polar (NP) and of the highest voltage rating you can obtain (100V minimum).
Having said all that, the experts are now sure to chip in with their alternative solutions!
Plus, the inductor required for the low pass filter would be large and expensive (in the order of 22mH at 100Hz).
If purchasing the capacitor, make sure it is non-polar (NP) and of the highest voltage rating you can obtain (100V minimum).
Having said all that, the experts are now sure to chip in with their alternative solutions!
I include a link to your Behringer KM 1700 amp for reference. Behringer | Product | KM1700
2 x 500W into 8ohm - you will need high power rated passive crossover components!
2 x 500W into 8ohm - you will need high power rated passive crossover components!
Yes i know that is the main problem. I know that indicators are especially expensive. As far as power goes I probably won't be pushing it to the limits since my subwoofers are only 250w rms each but i have tried to push the limits ��. Basically i can play "normal music" with bass kick drums no problem at max volume but if i play modern music with long, deep bass line subwoofers start getting a little warm after one song.
I'd be more concerned about the potential damage to your tops if you continue to run them in parallel with your subs without a high pass filter in circuit - that is a necessary requirement.
Don't worry i don't run them in parallel during high power testing I actually used a cheap *** Chinese amp board for the tops and turned it up until it got to the clipping ( it is not powerful at all) and than cranked up the subwoofers that were running on built subwoofer output on my eq. The results was crap load of bass but completely drowning out the highs. But that was just a test. I am just looking for a temporary solution until i get one more amplifier. It seems that just capacitors will be the best option. Thanks everyone.
Also i am still not doing anything professionally. For now I am still building a system and having fun in my backyard. Also now is probably not the best time to start throwing parties each night during pandemic... So I have time for experimenting.
Cheap “non-polar” crossover capacitors are really only meant for playing at polite levels in your living room. Cranking to ‘party’ levels often results in them heating up and exploding - especially when used as a mid range crossover at a low frequency. Use something designed to handle a couple amps of AC current - like a pair of 220uF/250V “snap-in” style electrolytics. Two 220 uf back to back makes 110 uf non-polar. That type of cap can be used for raw mains power supply filtering on the primary side of an SMPS, so they will handle the 50 watts or so of average power you’re likely to put into the tops.
Thanks for the suggestion. I know capacitors like to explode if used incorrectly. I work with electronics so i have a lot of experience with that lol.
Some thoughts:
- A proper passive crossover around 100Hz is going to be a PITA for various reasons, one of them being that the impedance curve of the mid-high cabinets will be anything but flat around there, so the crossover will not function as intended, unless you design impedance compensation (hint: big LCR network). Another reason being that the required components will be huge and expensive.
- A simple analogue line-level crossover, like the Behringer CX2310, will do the job properly, be cheaper than the proper passive crossover, and sound decent. Use one amp channel for bass and the other for the main speakers. It won't be stereo, but it will work properly.
Chris
- A proper passive crossover around 100Hz is going to be a PITA for various reasons, one of them being that the impedance curve of the mid-high cabinets will be anything but flat around there, so the crossover will not function as intended, unless you design impedance compensation (hint: big LCR network). Another reason being that the required components will be huge and expensive.
- A simple analogue line-level crossover, like the Behringer CX2310, will do the job properly, be cheaper than the proper passive crossover, and sound decent. Use one amp channel for bass and the other for the main speakers. It won't be stereo, but it will work properly.
Chris
That option will be a hell off a lot louder than a passive XO and sound 100x better. But is the CX2310 even available anymore? Didn’t see it last time I was browsing the PE site to look for something else. The DSP units have taken over most ‘real’ application spaces, but there are times when you want just a cheap analog XO. I did see PV and dbx, although they don’t break the $100 price barrier. You may be able to pick up one used for a song, as most pro users are ditching them. I keep a ‘floater’ CX3410 (more valuable to keep than the $30 I’d get for it).
The back to back caps aren’t a proper crossover by any means, but when something that can be salvaged out of a scrapped PC/AT power supply can protect a pair of tops from excursion damage, and do it today, you use it. Another cheapskate option is to build a pair of fixed high pass/low pass line level filters from a handful of TL072s and power the board with a wall wart. Depending on what’s lying around it could cost next to nothing. It would be similar to what is actually used in amps which have built in “crossovers” like the QSC GX series.
The back to back caps aren’t a proper crossover by any means, but when something that can be salvaged out of a scrapped PC/AT power supply can protect a pair of tops from excursion damage, and do it today, you use it. Another cheapskate option is to build a pair of fixed high pass/low pass line level filters from a handful of TL072s and power the board with a wall wart. Depending on what’s lying around it could cost next to nothing. It would be similar to what is actually used in amps which have built in “crossovers” like the QSC GX series.
I actually have a subwoofer output on my eq with adjustable crossover but only problem is i need to get another amplifier. I will definitely keep an eye out for second hand amplifiers.
You can get motor start caps, rated at 400 VAC. Not exactly cheap, but will survive anything an amp can throw at them.
Passive crossovers are never a good/practical idea between subwoofers and mid/highs.
* IF done properly they are expensive.
* you mention "parties" so DJ duty, which typically demands lots of Bass.
To boot, a lonely 12" per side can´t provide much of it, if at all.
Meaning as the Party turns hotter (so far so good) 😛 you´ll naturally start cranking volume up, and Bass demands will drive system into clipping .... muddying everything else.
Spending on that is same or more $$$ as investing in an extra amplifier, any cheap generic amplifier you can get, and an ultra cheap basic fixed crossover, which you can even DIY, we are talking 2 x TL072 and a few assorted parts.
IF due to Covid restrictions you only play Music at home, I guess you will not crank it up to clipping levels, by far.
Just stay there for a while, and at your own speed do things right.
Meaning getting a proper amp (150/200W per channel since you already have a 500+500 one for woofers) and building/getting a real cheap crossover.
Even the cheapest/simplest one will be "better" than a passive one, more predictable and accurate slopes, etc. and can easily be adjusted to other frequencies if you find it better after some use.
Try that with a passive one!!!
Biggest problem with that is that tops don't handle bass well. What do you think about this idea and can you give me some advice.
For now, adding the 100uF cap and playing at *home* party levels should do, later add active crossover and extra power amp and do it right.
The active crossover WILL keep harmful lows away and do a FAR better job than any passive you can build.