Vitruix

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vinylnvalves
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#1 Vitruix

Post by vinylnvalves »

Anyone used this free piece of software, Vitruix, Seems to have a lot more functionality than LTspice which looks to be embedded in it.

https://kimmosaunisto.net/Software/Software.html
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#2 Re: Vitruix

Post by jack »

vinylnvalves wrote: Tue Sep 13, 2022 6:48 pm Anyone used this free piece of software, Vitruix, Seems to have a lot more functionality than LTspice which looks to be embedded in it.

https://kimmosaunisto.net/Software/Software.html
I don't see any general SPICE capabilities or any mention of LTSpice in the license agreement.

It's a totally different beast - very specifically geared towards speaker design.
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#3 Re: Vitruix

Post by Scottmoose »

Absolutely. Different beasts; LTSpice is a circuit simulator, but for speaker design it's almost worthless. While you can model the electrical aspect of a filter, the actual on / off axis acoustic responses of the drive units on the baffle, their frequency-dependent varying impedances and their phase relationships (i.e. where they are relative to each other) are not included, and it's those you ulimately work with.

VituixCAD is by far the most comprehensive crossover design & modelling software freely available, and arguably superior to some rather pricy packages like LspCAD and (to a lesser extent) SoundEasy, although they do include built-in measurement facilities that VituixCAD does not have. Whether that's necessary or not given the availability of others is a matter of opinion (I should say, both of the others remain excellent -if I had the money to buy SoundEasy I would have done years ago) The learning curve is fairly steep if you go beyond the basics, and Kimmo's refreshingly blunt attitude is RTFM if you have a question that really shouldn't need to be asked, ;) although in fairness the pace of software updates does slightly exceed that of the manual. It's a formidable bit of work though; I use it, along with some other software depending on what I'm doing all the time.
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vinylnvalves
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#4 Re: Vitruix

Post by vinylnvalves »

Maybe i got my wires crossed :D , i meant from a crossover simulator perspective.

Having failed to get Jeff's cabinet designer to work on a new version of excel - backwards compatible, my ar*e. I am playing with Kimmo's tools. I am wanting to be able to simulate a aperoidic cabinet as i want to utilise a rear vent to generate a cardioid midrange, so it can go close to the walls without a big baffle. Kimmo's been a champion of cardioid cabinets for some years on DIYaudio - however i have not found how to model it in his software. Maybe he left the good bit out... :( or i need to play a little more.
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#5 Re: Vitruix

Post by Scottmoose »

You can simulate an 'aperiodic' (not really in most cases, but we'll never get shot of the the term now) cabinet in any decent box modelling software. Ultimately, most of the boxes so-described are just leaky seaked / resistively vented enclosures. If you use a sealed as the basis, simply increase the box losses. If vented, ditto and that of the vent friction losses.

TTBOMK however, wherever you put the vent, this isn't really going to create a cardioid polar response. Assuming the usual type of box described as an aperiodic, all it is is a leaky sealed box i.e. a monopole radiating into whatever angle is created by its position in the room & the latter's construction, damping etc.
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#6 Re: Vitruix

Post by chris661 »

Scott,

The Dutch & Dutch 8C has an 8" midrange unit which is a passive cardioid. They use vents towards the rear of the cabinet, which are combined with internal absorption to get a reasonable impression of a cardioid polar pattern in a range where rear-wall reflections are problematic.


IMO, it feels a bit "voodoo", and I'd rather play with combining omni + dipoles to get a cardioid over a couple of octaves.

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#7 Re: Vitruix

Post by Ant »

What would my big fanes class as in this instance? The big resistive vent is on the top of the cab, the box itself was sealed, 130l or so
Id be interested to see if they approximate a cardioid response
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#8 Re: Vitruix

Post by vinylnvalves »

Last time I did an aperiodic bass enclosure, designed it on the hoof by test, dull thud on spike input and the impedance curve humps. As Chris says it’s the opportunity to place the cabinet close to the wall, without the typical muddy midrange when using a narrow baffle. I have heard the DD8c - wasn’t a revelation, but better than most closer to a rear boundary.
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#9 Re: Vitruix

Post by Scottmoose »

Notwithstanding what merits or otherwise 'aperiodic' (a.k.a. leaky sealed boxes, i.e. a means of lowering the Q of an acoustically undersized sealed box) enclosures certainly can have -it's not a synonym for a cardioid polar response. The D&D 8C Chris refers to for e.g. may have a cardioid polar response (I've not seen any independent testing on this particular aspect to confirm in detail), but that will result from a combination of vent positioning, sizing & aspect ratio; the midrange will be partially unbaffled with Av of that size, so rear output will be present to a higher frequency than usual from a box speaker, then directed through said vents; the division & form factor plus internal damping will be playing a role however in providing some degree of acoustic low pass. As noted though, this is not in itself the same thing as aperiodic.
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#10 Re: Vitruix

Post by vinylnvalves »

So what your saying the DD8c isn’t aperiodically loaded, so is probably more akin to an H frame OB, which has a weak cardioid response? They probably did what they did to be able to fit the subwoofers at the back. Chris has invested more time than I have on Diyaudio in the discussion of the driver positioning especially close the rear wall.
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#11 Re: Vitruix

Post by Scottmoose »

I can't comment on DIYaudio unfortunately as I walked away from it some months ago. Be that as it may though, I've not seen anything to suggest the DD8C is aperiodically loaded as such. It might be, although my possibly simple mind would suggest that's bordering on an oxymoron if you're trying to create something other than a monopolar response: the object of an 'aperiodic' box, or what is usually so described, is to provide a better damped alignment than you'd get in a sealed box of the same volume -there's no audible output from the vent[s]. My point is just that 'aperiodic' describes a type of box load, not a polar response, which is a completely different thing.

Right, although I'd probably describe it as more akin to a (presumably somewhat damped) U-frame than an H-frame as only the rear of the midrange driver is doing any loading of the box / baffle / whatever you want to call it. ;) In that sense, similar to the LF leg of John Kreskovsky's NaO II, or other modestly damped open-back boxes etc. (which is in effect what they are).
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