Tilt = T-parameter then right? positive value is facing upwards
I understand I'm a pain in the a.... . Doing things for the first time isn't all that easy. It takes some experience to find a proper work method.
My speaker (40cmx100 and 15cm deep) stands on a workbench. Clamped so it doesn't fall off being so narrow and tall. (it's the only thing I have on hand of sufficient height)
I need to turn the workbench for the different angles. Turning it and keeping the rotating centre even isn't that easy.
This question the outcome of my measurements and hence the double and triple checking.
So now it's time to make a proper turntable.
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Load in your measured data, or the demo data available in the help page, enter some numbers in R and T, and observe the horizontal and vertical polar map, I'm sure you can figure it out! 😉
A few cases of stacked empties is all you need for that speaker 😉. Or some scrap wood or construction lumber can make a simple stand. With the work bench, attach a stick to it that runs down to the floor so you can point it at the polar map that you taped there and keep the point of rotation in check for each measurement.
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Is there a way to import transfer functions from LTSpice into VituixCAD?
It is an active six way system with monobloc 6 channel amplifiers feeding each transducer directly. The crossovers are line level passive at the input to the amplifier the frequency response of each is modelled in LTSpice. What I am hoping to do is export the transfer function (frequency response) for each amplifier from LTSpice into VituixCAD, measure the drivers, and then fine-tune the crossovers. Is this something that VituixCAD can accommodate? It looks like fantastic software.
It is an active six way system with monobloc 6 channel amplifiers feeding each transducer directly. The crossovers are line level passive at the input to the amplifier the frequency response of each is modelled in LTSpice. What I am hoping to do is export the transfer function (frequency response) for each amplifier from LTSpice into VituixCAD, measure the drivers, and then fine-tune the crossovers. Is this something that VituixCAD can accommodate? It looks like fantastic software.
Try the latest revision. It reads frequency response exports from LTspice IV, but newer versions are not tested.
2.0.88.6 (2022-08-19)
- Added support for frequency response export from LTspice.
Hello @kimmosto,
I would like to ask for a feature request.
Would it be possible to extend the frequency range of analysis to cover the frequency range from 0.1Hz to 1MHz?
The 0.1Hz lower limit is handy for some design studies looking at amplifier phase responses at very low frequencies.
I know that 1MHz might seem a trifle extreme, but for some amplifier systems that I've wanted to analyze, it would have been handy to check the roll-offs and phase responses at such high frequencies.
Thank you for considering my request.
I would like to ask for a feature request.
Would it be possible to extend the frequency range of analysis to cover the frequency range from 0.1Hz to 1MHz?
The 0.1Hz lower limit is handy for some design studies looking at amplifier phase responses at very low frequencies.
I know that 1MHz might seem a trifle extreme, but for some amplifier systems that I've wanted to analyze, it would have been handy to check the roll-offs and phase responses at such high frequencies.
Thank you for considering my request.
^No. Simulation is done in frequency domain and result is primarily in acoustical domain so extending frequency range by multiple decades with the same internal frequency step would drop performance radically providing some advantage for 1/3000 users.
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I understand the frequency domain/acoustical domain applications quite well. It's all a bit of a shame not to extend the frequency ranges. Computers are quite fast these days, aren't they? It would appear that the program is being unnecessarily hobbled by that design choice, but who am I to complain; I'm just a mere user. The ranges would be optional anyway, with the default range staying at 5Hz to 40kHz.
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I tried searching for this info but I'm afraid I still not sure about something. I probably don't understand it. Anyway, I'm measuring a tweeter and woofer in REW with an audio interface. I'm using https://kimmosaunisto.net/Software/VituixCAD/VituixCAD_Measurement_REW.pdf as my guide.
REW:
Now do I need to enter Z/delay in Vituixcad? Or leave it zero? (is it already baked into the FRD?) And if I need to enter it, what exactly do I use? Those measurements from REW?
REW:
- Woofer: delay 0,0883ms
- Tweeter: delay 0,0386ms
Now do I need to enter Z/delay in Vituixcad? Or leave it zero? (is it already baked into the FRD?) And if I need to enter it, what exactly do I use? Those measurements from REW?
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Joined 2003
The answer is in the guide, and even the last few posts in this thread.
Follow the instructions on page 9 for processing the data, for flat baffle speakers z=0, delay is captured in the phase response data. Enter physical x,y locations of the drivers in the crossover relative to the tweeter.
Ok thanks, that's what I thought. I need to go over all my other settings because my separate drivers all look identical to what VituixCAD predicts when I test my crossover, but the combined drivers are different. I'm gonna go read some more 🙂
Quick Beginner Question:
I am using VituixCAD's enclosure tool.
When I choose a driver from the database (in my case, SB Acoustics's SB17CAC35-8 see link), I get a set of parameters that match the published specifications on SB Acoustic's website. So far, all is good. https://sbacoustics.com/product/6in-sb17cac35-8/#tab-specs
When I use Step 2 of the attached instructions in post #3844 (see link) "Simulation Without Measurements" and try and Calculate the T/S using the traced Impedance Curve, I get slightly different driver specifications than those published by SB Acoustics or in the original database. https://www.diyaudio.com/community/threads/vituixcad.307910/page-193
For example, Published Fs is 28Hz, and Traced Fs is 30Hz. Qms 4.46 vs 4.01, Cms 2.13 vs 1.82, Vas 42L vs 36L, etc. Hence there is some difference in the enclosure response. Which set of parameters should I use? Thanks.
I used the merger tool to compare the SPL response. The blue curve uses the traced data, and the green curve uses the published data. I know the differences are minor, but I just wanted to know if this was normal.
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Member
Joined 2003
You should use the real measured parameters for your drivers once you have them in hand. You will read a clear disclaimer on page 1 of my document that its intent is to aid in learning of the tools available in VituixCAD, it’s not proposed to design any real speaker using traced data. The intent of the extra steps in extracting T/S from the traced impedance is to obtain a more accurate inductance model than the single Le value provided in most manufacturer specs. It also allows you to familiarize yourself with the software for calculating T/S before you build a jig and make a real measurement.
Using the extended Z model, it may provide a slightly different cabinet model, but hopefully one that is more true to reality. FWIW many people design their cabinets without consideration for Le at all.
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Can you direct me to "my document"?
I want to read everything I can on using VituixCAD.
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Joined 2003
Got it! Didn't realise the document you were referring to. I've already read it.
Thanks.👍
Circuit simulator with very simple ideal linear components such as OPA block is not valid for very high frequencies. Real spice would be better for that. The latest revision 2.0.88.7 is able to run optimizer fast no matter how wide internal frequency range is, but there are few other problems. Performance during normal manual adjustments would drop down to half if number of frequency points is doubled. Both electrical and acoustical transfer functions are calculated within whole internal range (except while Optimizer is running). Frequency response exports include full range. Frequency response files are read so that missing range at LF and HF is extrapolated to fill whole internal range. Response handling would be more complex and slow, and there would be more composed fake data if internal range is much wider than actual measured acoustical data. Timing calculations don't work at very HF with 48 ppo.
Of course range of electrical domain could be wider than acoustical, or range could be adjustable - just like in early VituixCAD versions before 2.0. That was bad and fragile system generating files with different scales. It was possible to lose actual measured data, and fill it with composed fake.
So condescending complaints will not help.
If my comment was taken as being condescending, I'd like to note that it wasn't intended to be.