XSim free crossover designer

[pawelp]

Yeah, usually more info is better than less However, initially I'll go as most people do for on-axis optimization and then listening trial & error.
Anyway, the key principle for this xover is more impulse timing optimization than FR. I find timing the most underappreciated and undervalued feature in speaker design.
That's why coax is here For me coax actually should simplify the design rather than make it more challenging. Why do you think it's more tricky than separate drivers ?

[AllenB]

In that case, could you have Xsim show the individual responses as well as the circuit.

[kimmosto]

Originally Posted by pawelp

I find timing the most underappreciated and undervalued feature in speaker design.

Also coaxial can have excess group delay due to crossover such as any other multi-way. Also time alignment (including excess GD) could be off. So there's not much difference - certainly not so much that you should ignore something else.

[kimmosto]

Originally Posted by pawelp

Why do you think it's more tricky than separate drivers ?

Just look the datasheet. Is on-axis, 30 deg or 60 deg the right one and representative for crossover design or not? Or is it electrical response based on assumption that tweeter of coax converts balanced electrical power to balanced acoustical power?
Single off-axis response could be representative, but the problem is to know which one.

[pawelp]

>Also coaxial can have excess group delay due to crossover such as any other >multi-way.
Obviously, but this has little to do with coax.
>Also time alignment (including excess GD) could be off.
Do not get it - for me this sentence is basically the same as the previous one - no time alignment but solely due to the xover. So you "just" should be careful with the xover to preserve it. As far as it is doable with a pasiive xover of course... I shall also do a DSP xover version as a next step shortly after passive.
>So there's not much difference - certainly not so much that you should ignore >something else.
For me there's a whole lot of difference - without a coax you have a serious built-in compromise in time alignment and the xover is rather on top of that.
It is not about ignoring just setting the priorities for the case they cannot be optimized simultaneously

[pawelp]

The mid and twt part - I am focused on them for now.

Maybe someone could give me a hand where to find a tool that would calculate a notch (RLC) for the 4k peak - 5dB, Q=5 ?

[kimmosto]

Originally Posted by pawelp

without a coax you have a serious built-in compromise in time alignment

For example TAD Compact Reference CR1:


Some real life 4-way with separate conventional drivers:


Built-in compromise in time alignment is quite well handled isn't it? Of course you are free to focus any individual feature and use as narrow view to reality as you like. Not my bad.

[pawelp]

The 4-way seems to look nice. The question is at what mic location was the measurement taken and how it changes with a few cm mic repositioning.

I am always interested in alternative points of view. So in my practical Seas coax drivers case what would be your approach to xover design ?

[pawelp]

Originally Posted by kimmosto

For example TAD Compact Reference CR1:

Interesting discussion and example
My first impression of this IR was it is not my high fidelity.
But if understand this correctly on a fast glance actually the key timing problem here is the woofer being delayed and that's less of a problem.
The mid and twt are not fully in sync but how problematic it is would need some closer analysis and comparing how it compares to other commercial products.
What is your view on that ?
If you attached a well-behaved 4-way doesn't it mean you also pay quite a bit attention to it ?

[bwaslo]

Originally Posted by pawelp

The mid and twt part - I am focused on them for now.

Maybe someone could give me a hand where to find a tool that would calculate a notch (RLC) for the 4k peak - 5dB, Q=5 ?

Have you tried using the Xsim circuit blocks, for a series resonant circuit? Put it across the driver (or earlier in the network -- but NOT across the power amp) and a resistor or other series impedance ahead of it.

But XSim was designed to be mostly used iteratively, to avoid things like needing formulae and related tools. Put in the component arrangement for what you are after, then scroll through values of eac components to see what happens -- it doesn't take long to get a feel for what is going on or for the size of inductors, resistors or capacitors that affect the frequencies you desire. I think that way is more instructive than using some online calculator (which seldom gives the expected results when attached to real world impedances like those of drivers).

BTW, it might be better if you attached the '.dxo' file for your crossover to your post. Then other people can start with what you have, including the driver responses and impedances you are using (those are part of the .dxo), Not many members here will want to spend the time to enter the circuit by hand and guess what your drivers behave like. With a dxo, they can just click, open, and play with components.

edit: for example, download (click in most browsers) to get this example, play with C6 to see how it behaves, then with other components like L4 and R5.