The LXmini crossover you have bought is a totally diffent crossover from the Biamp 6-24 Crossover. It is rather obvious that not everyone understand what these two crossovers are doing. Many like to replace a passive crossover but do not understand how passive crossovers work with their drivers, it is rarely simple 6-12-18-24 dB/octave electricly that are needed for active crossovers and this is what Biamp 6-24 is comes in and give a more adjustable active crossover. The LXmini crossover is another special with a more specific speaker in mind, the LXmini.
First of all, it is good to have a target for what you want the crossover to do!
First of all, it is good to have a target for what you want the crossover to do!
What is the difference? LXmini states it can be adjusted for other purposes. This is why I bought it. 6-24 was not available/advertised at that time. Should I adjust LXmini or return it and buy 6-24? Thanks!
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If you want to creatively kludge the parts, you can make either board
into the other. The 6-24 is much more adjustable/flexible but doesn't
have the EQ built in. If 6/12 slopes are all you need then the ACN can
take care of it. If you need 6/12/18/24 and EQ, then probably you need
separate EQ. If you have both these boards, then you have everything.
into the other. The 6-24 is much more adjustable/flexible but doesn't
have the EQ built in. If 6/12 slopes are all you need then the ACN can
take care of it. If you need 6/12/18/24 and EQ, then probably you need
separate EQ. If you have both these boards, then you have everything.
Member seeks advice about PSU for 6-24 crossover
A member sent me a PM containing lots of questions about power supplies for the 6-24 crossover. Since I strongly believe the collective wisdom of the entire membership far exceeds my own (especially since I've never studied, seen, touched, or owned one of these crossovers!!), I'm copying the questions here. I hope one or more readers may be able to help this person achieve their goals. Her/his diyAudio screenname, when shortened, becomes "VR".
Thank you in advance, on behalf of member VR.
A member sent me a PM containing lots of questions about power supplies for the 6-24 crossover. Since I strongly believe the collective wisdom of the entire membership far exceeds my own (especially since I've never studied, seen, touched, or owned one of these crossovers!!), I'm copying the questions here. I hope one or more readers may be able to help this person achieve their goals. Her/his diyAudio screenname, when shortened, becomes "VR".
Thank you in advance, on behalf of member VR.
What I would do to start with is use the onboard power supply to support the smoothing and reference voltage for analogue circuits on each board.
That way the boards will power up correctly first time and in the event of a fault elsewhere it will be more straight forward to trouble shoot. It’s unlikely that a completely new regulated PS will offer better smoothing with these kinds of circuits. A regulated DC linear supply can be simply used in place of the 24 volt smps if desired.
The point to understand is that these are single supply circuits and the on board PS and the pcb has been set up to provide the Ref voltage for the Jfets.
The +ve power wiring for each board and ground should go to a common smps with a star ground earth. Some experimentation may be required to obtain the best noise performance with the grounding of the input and output signal ground.
To keep the project as simple as possible from a build and test perspective I suggest building the crossover with two of the boards to start with as an unbalanced design.
The idea of a complete dual balanced system may seem like a cool idea. But the cost, complexity and time involved in assembly and testing many not be justify the perceived benefits.
Getting the real benefits of a balanced design are often difficult to obtain in practise as even small imbalances in the impedances of the input and output circuits have dramatic effects on the CMRR. These SE circuits already have low THD with little 3rd and higher harmonics. You may prefer the slight negative phase character of the 2nd harmonic in these SE circuits which would be cancelled some degree in a balanced design.
Below l have outlined a block diagram using two of the crossover boards.
There are a number of good references to balanced small signal circuits on the www.
Balanced Interfaces
That way the boards will power up correctly first time and in the event of a fault elsewhere it will be more straight forward to trouble shoot. It’s unlikely that a completely new regulated PS will offer better smoothing with these kinds of circuits. A regulated DC linear supply can be simply used in place of the 24 volt smps if desired.
The point to understand is that these are single supply circuits and the on board PS and the pcb has been set up to provide the Ref voltage for the Jfets.
The +ve power wiring for each board and ground should go to a common smps with a star ground earth. Some experimentation may be required to obtain the best noise performance with the grounding of the input and output signal ground.
To keep the project as simple as possible from a build and test perspective I suggest building the crossover with two of the boards to start with as an unbalanced design.
The idea of a complete dual balanced system may seem like a cool idea. But the cost, complexity and time involved in assembly and testing many not be justify the perceived benefits.
Getting the real benefits of a balanced design are often difficult to obtain in practise as even small imbalances in the impedances of the input and output circuits have dramatic effects on the CMRR. These SE circuits already have low THD with little 3rd and higher harmonics. You may prefer the slight negative phase character of the 2nd harmonic in these SE circuits which would be cancelled some degree in a balanced design.
Below l have outlined a block diagram using two of the crossover boards.
There are a number of good references to balanced small signal circuits on the www.
Balanced Interfaces
Attachments
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Hi Roger,
You make a good point.
This type of project is not like a preamp or a power where you build it from a set schematic and a bom and plug it in and it goes.
Imagine you are building a Riaa stage for phono cartridges that requires specific Riaa curves in each case. An active crossover is much the same challenge except it’s for two or more loudspeaker drivers.
So logically the diy guy needs to have an understanding of not just how it works but how to design a curve specifically for his drivers. To many this is all new concepts and how to skills that to the uninitiated are going to create lots of questions.
There needs to be a process and structure behind completion of a successful project to avoid, confusion, frustration and abandonment.
There are a number of avenues to the end result but it’s best to have the right starting point.
So there are two roads.
1. Are you designing an active crossover for an existing passive loudspeaker design?
Or
2. Are you designing a Biamp or Triamp loudspeaker from scratch?
3. Then next step may appear to be attempting to fit one of the kits hardware to your plan for 1 or 2. However, the best place to start is always the start and that means collecting from useful data by way of measurements for 1. The system voltage drives. 2 Acoustic response measurements of your drivers mounted in the proposed enclosure.
This can readily be done at low cost with REW and a Mini dsp USB microphone.
It’s not difficult and you will be well rewarded later.
Once you have the measurements you have a basis for making some informed decisions around what filter slope and crossover frequency are best to use in your project. As Nelson points out it will take some experimentation to come up with a crossover function that measures well and is subjectively acceptable.
The thing to understand is there is a huge amount of knowledge in designing and successfully building your own loudspeaker. Things like baffle step compensation, driver EQ and response optimisation for a specific room locals come into play if your goal is to attempt something better then you can afford to buy.
4. Once 3 has been looked into you can then start the process of calculating the RC values.
5. Build out the kits.
6. Test and learn.
Here is a great primer
https://www.ti.com/lit/ug/tidu035/t...url=https%3A%2F%2Fwww.ti.com%2Ftool%2FTIPD134
To go along with Macka's suggestion to increase fun and decrease frustration. People might consider buying a miniDSP 2x4 to help experiment with crossover settings before committing to resistor/cap values in the 6-24. $85 on parts express and you can sit in your listening chair and try every possible crossover setting available on these boards. One click and it's changed with immediate audio feedback. Once you've got it dialed in, then you can build the better sounding non-digital version Nelson provides. I know it increases project cost, but this device is a great deal for the functionality it provides and the frustration it can eliminate.
That's exactly what I'm doing right now
I then plan to on sell the dsp, so not a big increase in project costs.
Dayton Audio do a nice dsp active crossover too that is worth considering.
Dayton Audio DSP-408 4x8 DSP Digital Signal Processor for Home and Car Audio
Dayton Audio DSP-408 4x8 DSP Digital Signal Processor for Home and Car Audio
Dayton Audio do a nice dsp active crossover too that is worth considering.
Dayton Audio DSP-408 4x8 DSP Digital Signal Processor for Home and Car Audio
Here is the Heil driver I was alluding to earlier
404 Not Found – ESS Speakers USA
Are you guys aware Nelson worked at one time for ESS?
Dayton Audio DSP-408 4x8 DSP Digital Signal Processor for Home and Car Audio
Here is the Heil driver I was alluding to earlier
404 Not Found – ESS Speakers USA
Are you guys aware Nelson worked at one time for ESS?
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I think there was earlier discussion that the 221k resistors are a silk screen error, and those should be 1M instead.
Yes, and that is also where the SLOB concept was first conceived by Nelson
When I eventually get to build the filters - just ordered also the LXmini/basic boards so that I can do "everything"
needed for my OB system. It is also featuring the ESS Great Heils. Next step is running these stacked together with 4x 15PR400's - but at my current speed 
I am afraid that Nelson is going to beat me to it when it comes to presenting value recommendations.I am currently running these on MiniDSP 2x4HD (and 4x10HD if with SLOB subs) As mentioned earlier here - running the MiniDSP almost feels like cheating - it's like moving from the darkroom to digital, learning loops
are faster. For the ultimate result it will still be hard to beat a proper large format setup...... but in the end it's all limited by the guy/girl behind the gear & setup 
...ohh and If you do not have a proper goal before starting out....it will show in the result, some say that a sharp concept in a fuzzy picture always beats a sharp picture with a fuzzy concept.... probably that goes for soundscapes as well
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