XSim, a free schematic-based crossover designer - AVS Forum
DIY Speakers and Subs > XSim, a free schematic-based crossover designer
bwaslo's Avatar bwaslo 09:01 AM 07-30-2014
I'm announcing the public release of XSim, a "free-form" Windows-based passive crossover design and simulation program intended to be as intuitive and non-restrictive as possible. . The program is ***free*** for personal or commercial use. Any speaker builder with at least a basic understanding of what resistors, capacitors, and inductors do, and with decent response measurements (FRD and ZMA) of their drivers in their boxes, should be able to get useful results right away.

download from:

Experimenting with "ideal" driver data (the default for each driver) can also be fun and helpful in understanding the effects of various circuit types. Some built-in multi-part "Circuit Blocks" also provide for basic pre-configured circuits to be tuned per their overall parameters (Q, corner frequency, attenuation, etc). There are "Example" files inlcuded in the XSim download (currently less than 1.5MB) as well.

XSim allows you to see simultaneous multiple graphs of your choice, including impedances, voltages, power consumptions, group delay, and frequency, impulse, step, and square wave responses. You can watch the performance and/or stress on any part vary as you tune structure or component values in real-time. The circuit network is re-solved automatically with every change you make.

The "free-form" aspect of XSim is that crossover designs are unrestricted, no particular circuit structure need be used. Essentially any R-L-C passive network you can think of can be easily entered using graphical schematic entry, with results calculated as you design. A common "ground" node is provided, but its use isn't required.

Circuit designs (incuding all in included driver data sets) can be shared by email or forum post in XSim's ".dxo" format. Graphic files can also be saved in standard picture file formats.

Stuff yet to come:
The release version of XSim featiures automatic downloading of part and driver information based on vendor and part number, making it easy to find and order what you need to turn your design into working hardware. However, no vendors are as yet signed up to provide XSim access to part or driver information. XSim will be able to download these lists itself, when available. XSim can also update its own program (with owner permission) so people who use it online can always be up-to-date. ...And so I can add or fix features without asking you to deal with downloading and installing each time.

XSim does not yet include geometric features (such as varying mic position, baffle or boundary-bounce effects) as in Jeff Bagby's very successful "PCD" and other programs derived from it. But that is in the works, with some assistance from Jeff. There are also as yet no box-design features, but this is also planned so that full designs can be worked with using the infinite baffle data provided by vendors.

tuxedocivic's Avatar tuxedocivic 09:27 AM 07-30-2014
Yahoo! 'Bout time man

To all who are wondering, this is a very nice XO design tool. Bill has done a fantastic job. If anyone would like to try messing around with XO design, I can give you some files to try. Just PM me. I can field questions about how to use the software also. But it is pretty easy to figure out also.

Congratulations Bill
Bassment's Avatar Bassment 09:59 AM 07-30-2014
andyc56's Avatar andyc56 10:13 AM 07-30-2014
That's amazing, Bill. Congrats!
Mark Seaton's Avatar Mark Seaton 10:52 AM 07-30-2014
Bravo Bill, very impressive work!

I very much like what I see at first glance. It was nice to intuitively grab for "Ctrl+R" and see the part rotate. I was even more surprised to see the graphs immediately display once a complete connection was made. The functions available really make it an impressive, experimental learning tool for those not yet familiar with circuit analysis and how parts work/interact.

This also makes it very easy to experiment with circuit ideas which are less commonplace or not so easy to add to some interfaces. I realize much can be done with PCD already, but the speed and intuitiveness of XSim is very impressive. When you do get to the box modeling, the ability for DIYers and experimenters to start looking at circuits driving modeled impedance curves before a box is built will be huge. While it's possible now, so few take the time to look and see if that nice flat response is still there when you try to put your intended crossover in place and can allow guys to realize some less obvious combinations or solutions to a flat end result.

Another highly useful feature in the "Tune" window are the added options of "open" and "short". This is not directly available in most tools and allows you to retain the last entered value while bypassing or removing the component from the circuit. Was there an intended reason why the mouse jumps back over the component when selecting open/short, or the tune window closes when switching back to "value"?

About the only quirk I found was with the wiring tool and moving components. While I like the automatic wiring tool when hovering over a node, once the wire is drawn, it appears you have to delete and re-create the wire if you need to shorten or if you move components that are already wired. I'm sure this drag/extend/modify function I've seen in some spice editors isn't just a simple addition, but if possible down the road it would be even more impressive. In the mean time I'm happy to redraw some wiring for the quick functionality of Xsim.

I can only imagine the work that went into getting the functionality we see. While I know you aren't trying to make a living off this, down the road I would suggest adding a small block at the bottom of the schematic window to place modest adds from DIY suppliers and charge a modest fee to get rid of the add block to support the time and effort... and to buy yourself new toys here and there.

Don't hesitate to contact me if there is any way I can help.
bwaslo's Avatar bwaslo 11:08 AM 07-30-2014
Thanks, Mark (and everyone else, too!).

The program does have a financial aspect, though. While free to users, I'm planning to "rent" use of the program to feature vendors' parts/drivers at a monthly rate, that's what the download stuff is about. Kind of like magazine advertising space, but much more functional and direct. I think something like this would be a big boost to companies selling drivers and crossover parts. Easy searching for crossover parts of the values you want, and simulating how they would work, should make actually ordering them more likely!.

It would also help speaker parts vendors if more people in general became speaker/crossover designers, which I think is more likely if people can play with them without first starting with sawdust and expensive doubtful parts purchases. Jeff's PCD did a great thing in providing that before . XSim is aimed to go further and also include part number shopping (and maybe someday, ordering too.

As I'm officially retiring from "the day job" next Wednesday (!), I'm hoping XSim can somewhat help my retirement income. Time will tell...
bwaslo's Avatar bwaslo 11:12 AM 07-30-2014
Mark, I'm not seeing that mouse hopping (or tune window closing) you mention. Can you tell me what version of Windows you are using, it might have something to do with that. Development was done/tested in Win7 and Win8 (yeah, I know...).

Ok, I see the mouse hopping issue. I'll look into that. Didn't run into it before because I usually just hold the mouse cursor over the component and type "O", "S" or "N" for open/short/normal rather than using the tune window for it.
Mfusick's Avatar Mfusick 11:14 AM 07-30-2014
Bill that's great ! WELL DONE!
Mark Seaton's Avatar Mark Seaton 11:31 AM 07-30-2014
Good plan on the parts library concept. A logical way to make it work long term, and congrats on the upcoming retirement!

Originally Posted by bwaslo View Post
Mark, I'm not seeing that mouse hopping (or tune window closing) you mention. Can you tell me what version of Windows you are using, it might have something to do with that. Development was done/tested in Win7 and Win8 (yeah, I know...).
The computer I'm on at the moment is still Vista. I'll check on my others later. The hopping to the component is consistent when selecting open or short, but not value. The window closing happened only 1-2 times on a couple parts and then did not repeat. Entirely personal GUI preference... but I would like if the Tune window popped up with a double-click on a part rather than the right-click and first selection. The component power/current/Voltage is very useful. Might you be able to add test probes to analyze specific filter blocks or segments? Obviously there are already some easy workarounds with a high impedance resistor.
Willie's Avatar Willie 11:42 AM 07-30-2014
Originally Posted by bwaslo View Post

As I'm officially retiring from "the day job" next Wednesday (!)
Congrats! Not sure everyone understands how cool it is to be able to retire from the day job. And BTW, my Cheap Thrills bring me great enjoyment on a daily basis.

bwaslo's Avatar bwaslo 11:46 AM 07-30-2014
I think I know what's happening on the Tuning window there. If the mouse isn't in the tune window (or on the part being tuned) and nothing has been tuned in some seconds, the tuning window closes. Maybe that's not needed anymore to clean things up. In some previous versions I had it so you could just put the cursor over a part and spin the mouse wheel and the part value would adjust, but that could get infuriating at times when the wrong thing would get focused. It was fast to tune things, but could made things feel out of control when using it.
lilmike's Avatar lilmike 06:22 PM 07-30-2014

Thanks for your efforts, this looks amazing!
Gorilla83's Avatar Gorilla83 07:19 PM 07-30-2014
Very impressive, Bill! Thanks for sharing this with us. Looking forward to playing with it some more this weekend.
A9X-308's Avatar A9X-308 08:05 PM 07-30-2014
Very nice Bill. Thank you very much.
davewantsmoore's Avatar davewantsmoore 09:18 PM 07-30-2014
Nice! Thanks.

Feature request: Undo / Redo
DS-21's Avatar DS-21 04:23 PM 07-31-2014
Thanks. Looking forward to playing with it!
Jim Himes's Avatar Jim Himes 07:58 AM 08-01-2014
Thanks Bwaslo! Great idea and works very well. I won't be using PCD or WINPCD any more. Bravo!

I look forward to the crossover components/drivers being added to the libraries. I hope the companies jump on the idea. Also it'll be great when you add the box section.

You could do something like REW does for a donation. People could donate if they wish but don't have to. I for one would donate a couple of bucks. When I use free software like Xsim or REW and it's functionality is as good as these are I open my wallet and give a little to the designer.

How long did it take you to put this together (guesstimate)?
bwaslo's Avatar bwaslo 09:02 AM 08-01-2014
About a year in spare moments (including about 4mos in the hospital! Work in that period slowed by heavy pain meds.).
mhutchins's Avatar mhutchins 10:59 AM 08-01-2014
Very nicely done, Bill. The whole DIY community owes you a debt of gratitude for this impressive tool.

And like Willie, I too am enjoying my Cheap Thrills (listening to them right now, in fact).

onebadmonte's Avatar onebadmonte 01:32 PM 08-01-2014
Awesome tool. Thank you.
HopefulFred's Avatar HopefulFred 08:46 PM 09-10-2014
This needs a bump - Thanks Bill for the very successful tool. It really is intuitive and easy to use. I'll need a lot more experience to interpret some of the graphs and such, but it has been very easy for me to slap together something that looks like it might work. I think if I can go from raw measurements to something I want to try in an hour or two with zero experience or instruction, it's a win.

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