Hey everyone! Back at it again, still wrapping my head around how to set up this whole system. Thinking it'll be two front speakers with a couple of bass units crossed over around 90Hz, using 24dB slopes.
Main/Front Speakers. So, for the main/front speakers, I really want to keep them as pure as possible. My plan is to go straight into the high-pass bit without even messing with an input pot.
Bass. Now, the bass is where I want some wiggle room. I'm dreaming of having a stepped stereo attenuator right on the front panel so I can easily tweak the bass level depending on the situation. I'm using a DBX 223 right now, and you know how it is – during those late-night listening sessions when the volume's super low, the system just sounds way better with a bass boost, usually like 3-6dB depending on the recording. It's crazy how immersive it is listening at 4am at low levels and still feeling the scale. Turns out, this is just variable loudness control, duh!
The circuit I'm using doesn't have any gain, but I've got a sweet solid-state line stage lying around that can run on the same DC voltage. It's got a really low input impedance. I'm thinking the best way to hook it up would be like this:
Input signal ---> low-pass part of the "6-24 crossover" ---> stepped pot + line stage --> bass amp
What do you guys reckon? Any thoughts?
Main/Front Speakers. So, for the main/front speakers, I really want to keep them as pure as possible. My plan is to go straight into the high-pass bit without even messing with an input pot.
Bass. Now, the bass is where I want some wiggle room. I'm dreaming of having a stepped stereo attenuator right on the front panel so I can easily tweak the bass level depending on the situation. I'm using a DBX 223 right now, and you know how it is – during those late-night listening sessions when the volume's super low, the system just sounds way better with a bass boost, usually like 3-6dB depending on the recording. It's crazy how immersive it is listening at 4am at low levels and still feeling the scale. Turns out, this is just variable loudness control, duh!
The circuit I'm using doesn't have any gain, but I've got a sweet solid-state line stage lying around that can run on the same DC voltage. It's got a really low input impedance. I'm thinking the best way to hook it up would be like this:
Input signal ---> low-pass part of the "6-24 crossover" ---> stepped pot + line stage --> bass amp
What do you guys reckon? Any thoughts?
Hi Piecor,
Your idea of a volume pot at the output of the crossover is not going to work properly. This is because the pot requires a high load impedance of at least 10 x the value of the pot.
The power amp of solid state will not have a high impedance input.
You can only do this with a buffer stage after the pot,
Therefore wire the chassis front panel pot to the trim pot tabs at the input to the filter. Use a log pot. It will work fine.
Bear in mind this kit was not meant to be customised on the fly or re designed. If you start modifying it and you make a mistake it will be more difficult to find the error.
I’ve used this kit with NP and Silmic 11 coupling caps and it works perfectly with a high quality system. I recommend to keep to the specified parts at the outset and look at your preferred parts once you know you have it working correctly.
Ideally to make your life easier use a dsp power amp with built in EQ functionality for the woofers. In addition if the power amp has a level control use that and turn the trim pot up full in the crossover.
The main thing about this circuit is it very transparent where you need it in the mid and high frequencies. The simpler elegant circuit it often the best.
Enjoy
Your idea of a volume pot at the output of the crossover is not going to work properly. This is because the pot requires a high load impedance of at least 10 x the value of the pot.
The power amp of solid state will not have a high impedance input.
You can only do this with a buffer stage after the pot,
Therefore wire the chassis front panel pot to the trim pot tabs at the input to the filter. Use a log pot. It will work fine.
Bear in mind this kit was not meant to be customised on the fly or re designed. If you start modifying it and you make a mistake it will be more difficult to find the error.
I’ve used this kit with NP and Silmic 11 coupling caps and it works perfectly with a high quality system. I recommend to keep to the specified parts at the outset and look at your preferred parts once you know you have it working correctly.
Ideally to make your life easier use a dsp power amp with built in EQ functionality for the woofers. In addition if the power amp has a level control use that and turn the trim pot up full in the crossover.
The main thing about this circuit is it very transparent where you need it in the mid and high frequencies. The simpler elegant circuit it often the best.
Enjoy
Hello, sorry I wrote it wrong, I wanted to correct the message, but the forum doesn't allow me to do it after more than 30min.
The line stage circuit I have is pretty good quality, it has high input and low output impedance. sorry
Hello piecor,
I run my active system like:
source - preamp - active crossover - amps.
The 6-24 AXO has inputbuffers and buffercells with very low outputimpedance.
Volume adjustment for lowpass and highpass is on the pcb of the 6-24 AXO (50 kOhm - trimpot at input of each filter).
You can exchange the trimpot with a stepped attenuator or logarythmic pot ( I used linear 10-turn-pots).
My two 6-24AXOs drive every amp I have.
Only my thoughts.
Cheers
Dirk
I run my active system like:
source - preamp - active crossover - amps.
The 6-24 AXO has inputbuffers and buffercells with very low outputimpedance.
Volume adjustment for lowpass and highpass is on the pcb of the 6-24 AXO (50 kOhm - trimpot at input of each filter).
You can exchange the trimpot with a stepped attenuator or logarythmic pot ( I used linear 10-turn-pots).
My two 6-24AXOs drive every amp I have.
Only my thoughts.
Cheers
Dirk
Wouldn't changing the level for the bass circuit on the fly (after crossover design is finalised) be changing your crossover point? Thus undoing all your good work? Ok if phase is not something you are concerned about, I guess.
What you propose, technically will work, but consider that the change in bass would be more like a shelf filter than a loudness EQ. And as @maFrodite mentioned will likely upset your crossover transfer function. I've considered using Nelson's Full Range EQ board after my low pass filters to give a little bass boost to sealed woofers. Seems like it could work as a loudness EQ as well since it gives a sloped LF boost, increasing as frequency decreases.
I'm in the build process of a 6-24 being used on top of an LX-mini I have already built. I'm tri-amping some open baffles I built that use the Qualio IQ as inspiration, but using a pair of 16 ohm (wired in parallel so = 8 ohms), 12" drivers in open baffle for the woofers instead of a box), and a similar to the Qualio's Mid/tweet open baffle on top.
The LX-mini low passes the woofs and and high passes the mids at 550HZ.. I'll be using the 6-24 with a 6db low pass @ 8000hz (eight thousand) for the mid/ full range driver (Satori 6 1/2) and a 12db high pass for the super tweeter (Mundorf 17D2.2).
I am mirroring the passive crossover points that Qualio made, but making this a completely active setup with an amplifier for each range.
So the 6-24 will see the 550hz high pass from the LX-mini as the input. The 6-24 will be set initially with an 8000 hz crossover point. Using the given math for C, I come up with .75 nf. This is 750 picofarads. and the closest /2 I could find is 390 Picofarads (.39 nf). Very few cap selections at those values, but have found a Vishay that will work, a little on the large side, but workable. https://www.mouser.com/ProductDetail/594-2222-375-46751 , also a Vishay /2 cap, https://www.mouser.com/ProductDetail/594-2222-375-47391
I don't see any issues going forward with this (as a good baseline starting point).
I am using a sub using a highly modded Dahlquist LP-1 active low / passive high.
.... Jeff Davison
The LX-mini low passes the woofs and and high passes the mids at 550HZ.. I'll be using the 6-24 with a 6db low pass @ 8000hz (eight thousand) for the mid/ full range driver (Satori 6 1/2) and a 12db high pass for the super tweeter (Mundorf 17D2.2).
I am mirroring the passive crossover points that Qualio made, but making this a completely active setup with an amplifier for each range.
So the 6-24 will see the 550hz high pass from the LX-mini as the input. The 6-24 will be set initially with an 8000 hz crossover point. Using the given math for C, I come up with .75 nf. This is 750 picofarads. and the closest /2 I could find is 390 Picofarads (.39 nf). Very few cap selections at those values, but have found a Vishay that will work, a little on the large side, but workable. https://www.mouser.com/ProductDetail/594-2222-375-46751 , also a Vishay /2 cap, https://www.mouser.com/ProductDetail/594-2222-375-47391
I don't see any issues going forward with this (as a good baseline starting point).
I am using a sub using a highly modded Dahlquist LP-1 active low / passive high.
.... Jeff Davison
3 Way Active XO
Seeking opinions on a 3-way active crossover schematic (Low Pass, Band Pass, High Pass) on one board.
After searching through numerous posts, I haven't been able to find a complete diagram for a 3-way active crossover. My apologies if one exists and I've overlooked it.
Would anyone be willing to share their thoughts on whether this schematic represents a good approach?
Thank you.
Dan
Seeking opinions on a 3-way active crossover schematic (Low Pass, Band Pass, High Pass) on one board.
After searching through numerous posts, I haven't been able to find a complete diagram for a 3-way active crossover. My apologies if one exists and I've overlooked it.
Would anyone be willing to share their thoughts on whether this schematic represents a good approach?
Thank you.
Dan
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Hello dansa69,
you can do it simpler for a 3-way - active setup using two of the DIY-biamp 6-24 crossovers:
build one as a subwoofer crossover (crossover frequency anywhere around 80 - 100 Hz) and a second one for your desired crossover -
frequency (mid / high) and daisy-chain them.
I did this in my system: 6-24 AXO at 80 Hz between subwoofer (low output) and (high output) to second 6-24 AXO.
The second 6-24 AXO is set up for crossover frequency between 2000 Hz to 3000 Hz.
Then you can still use the two different 6-24 AXOs independently. Works and sounds like a charm for me.
I run two 12 inch subwoofers (stereo setup) from the 6-24 AXO (No.1) below 80 Hz (driven from an PA-amp or BA-3);
the bandpass (80 - 2500Hz at the moment) drives a 6.5 inch midbass from Scanspeak (driven from different Pass amps like M2X);
Highs are AMTs driven from the high output 6-24 AXO (No.2) with an ACAmini or F5.
Greets
Dirk
you can do it simpler for a 3-way - active setup using two of the DIY-biamp 6-24 crossovers:
build one as a subwoofer crossover (crossover frequency anywhere around 80 - 100 Hz) and a second one for your desired crossover -
frequency (mid / high) and daisy-chain them.
I did this in my system: 6-24 AXO at 80 Hz between subwoofer (low output) and (high output) to second 6-24 AXO.
The second 6-24 AXO is set up for crossover frequency between 2000 Hz to 3000 Hz.
Then you can still use the two different 6-24 AXOs independently. Works and sounds like a charm for me.
I run two 12 inch subwoofers (stereo setup) from the 6-24 AXO (No.1) below 80 Hz (driven from an PA-amp or BA-3);
the bandpass (80 - 2500Hz at the moment) drives a 6.5 inch midbass from Scanspeak (driven from different Pass amps like M2X);
Highs are AMTs driven from the high output 6-24 AXO (No.2) with an ACAmini or F5.
Greets
Dirk
Hi Dirk,
Indeed that would be an easier option but I am also trying to remove the unnecessary components including capacitors. Also I want to have a complete 3 way xo on each board.
Thanks for the suggestion.
Indeed that would be an easier option but I am also trying to remove the unnecessary components including capacitors. Also I want to have a complete 3 way xo on each board.
Thanks for the suggestion.
I'm certainly not an expert, but yes, that looks like the right way to do it. Logically, you should not need the output circuitry if you're feeding directly to another stage, and you should not need the input circuitry if fed directly from the previous stage, as long as there is at least one buffer between them. And of course you've got to jumper the L and R input so each board runs in mono. I don't know if that affects the input impedance. There was a previous post that showed the same configuration, but no one ever replied about the results or whether it even worked.
Here’s my implementation of the DIY 6-24 active crossover.
This was built to replace two ART CX311 analog active crossovers in my system.
The 6-24 consists of filters for sub, low, and high x2 for each left / right channel.
The sub low pass is at 150 Hz with 24 dB/octave slope and the low-high xo is 2.5 kHz also at 24 dB.
The power supply is my simple linear design with a 25VA toroid and an LT350 adjustable regulator.
The case from a scrapped piece of telecom equipment with addition of my front panel.
I used “Front Panel Designer” software from the Front Panel Express company but just made the panel myself using a piece of anodized aluminum from an old Apple power mac case.
The text and scales were applied with the toner transfer method.
Setup was fairly simple and done mostly on the bench since I already knew the xo frequencies that worked well with my speakers. Levels were adjusted by ear, as I did with the CX311s, and then I do a final check with REW afterwards.
I’ve been listening for about a week now and I like it a lot.
It just sounds far more clear and detailed than the CX311, which uses 14 of the NJM 2068DD dual op-amp.
Many thanks to Nelson for another great, elegant design.
This was built to replace two ART CX311 analog active crossovers in my system.
The 6-24 consists of filters for sub, low, and high x2 for each left / right channel.
The sub low pass is at 150 Hz with 24 dB/octave slope and the low-high xo is 2.5 kHz also at 24 dB.
The power supply is my simple linear design with a 25VA toroid and an LT350 adjustable regulator.
The case from a scrapped piece of telecom equipment with addition of my front panel.
I used “Front Panel Designer” software from the Front Panel Express company but just made the panel myself using a piece of anodized aluminum from an old Apple power mac case.
The text and scales were applied with the toner transfer method.
Setup was fairly simple and done mostly on the bench since I already knew the xo frequencies that worked well with my speakers. Levels were adjusted by ear, as I did with the CX311s, and then I do a final check with REW afterwards.
I’ve been listening for about a week now and I like it a lot.
It just sounds far more clear and detailed than the CX311, which uses 14 of the NJM 2068DD dual op-amp.
Many thanks to Nelson for another great, elegant design.