That 1mf capacitor will be part of the reason for the ~0 ohm woofer impedance.
And I have no complains to developer of this program or this forum, or anyone else - oposite. Just as stated, not everyone is "technicaly minded".
Why it doesnt show up in impedance graph that its close to zero? Or am I reading it incorectly? Please corect me.
I'd expect a capacitance value in the low hundreds for an inductor like this. 1mF is just too big.
I'd check the resonance impedance peak isn't behind your troubles.
1. Set the impedance to the default flat setting (create a new driver and don't set the impedance, leave it resistive.. just set the response.
2. Use just an LC low pass, remove the other components for now. If you can get that to cross then...
3. Load the impedance file, remove all components and set an impedance compensation filter (RLC) before anything else.
I'd check the resonance impedance peak isn't behind your troubles.
1. Set the impedance to the default flat setting (create a new driver and don't set the impedance, leave it resistive.. just set the response.
2. Use just an LC low pass, remove the other components for now. If you can get that to cross then...
3. Load the impedance file, remove all components and set an impedance compensation filter (RLC) before anything else.
In difraction tool, when you specify baffle dim and if I have 2x woofer drivers, should I put them there, or just one? Question rise as it will be populated as for one driver data, is it?
Adding a series resistance increases the impedance seen by the amplifier. The 15OB350 has an Re=7.2ohms. The 3.3ohm resistor in your circuit attenuates the output of the 15OB350 by quite a few dB, and it dissipates quite a large fraction of the input power to do so. Is that really what you want? There is a possibility that the resistor may overheat, unless it has a very high power rating.
That would likely have been in parallel with an 8-ohm driver, and might have been used to equalize the inductive impedance rise a little, and to perform some response shaping. The quite simple first-order filter network on that woofer might have benefitted from that approach.
Based on the very large values of the two series inductors and the large capacitor of the 15OB350's filter network, you are trying to achieve a 3rd-order low-pass filter with a very low cutoff frequency. What is your target −3dB frequency? I am getting around 45Hz or so when using a constant resistance of 8ohms.
Your filter circuit may have difficulties working the way that you want it to. The reason for this is the presence of the impedance peaks associated with the woofer enclosure tuning, which I assume is a vented box. A driver impedance peak produces reactive impedance behavior that is anything but resistive, being capacitive and inductive either side of the peak.
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I'm not so sure that is the case. With an 8-ohm resistive load, we get the following filtered response (driver is set to 95dB sensitivity). The response is a quite reasonable looking 3rd-order low-pass response. The large component values are needed because we have a "driver" that is somewhere in the vicinity of 11ohms series resistance, and the inductors and capacitors therefore need to be commensurately larger. Although there is a dip in the impedance, it's still a long way from zero ohms.
Reducing the value of the capacitor from 1mF to 220µF produces the following response. The cut-off frequency has been increased by an octave or so, and the response shape now has some ripple.
The impedance minimum is also a bit higher:
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@witwald I dont know what I am doing, as I have never done anything technical, or electronic. I am trying to use @perrymarshall BassBoost for 2x SB 15OB350 drivers crossover passivly to FaitalPRO 12fe330 driver.
I am failing to get enywhere till this point. I have opened thread here about new speaker build, and was directed towards VituixCAD, and for now, as much it may be usefull tool, its not. https://www.diyaudio.com/community/threads/first-speaker-build.421311/page-3#post-7886314
I am failing to get enywhere till this point. I have opened thread here about new speaker build, and was directed towards VituixCAD, and for now, as much it may be usefull tool, its not. https://www.diyaudio.com/community/threads/first-speaker-build.421311/page-3#post-7886314
Hi, It's very useful tool, best there is available for what you try to do, or what anyone tries to do with loudspeakers, par none. Just take your time to understand what you are doing, and it'll work out just fine. Everyone has to learn new stuff before being able to utilize no matter what you do. No shortcuts, unless you pay for someone else do it for you, and sometimes barrier to entry is quite high so can be bit frustrating. This is not to let you down but hopefully to encourage you to get through your hurdle. Happy new year!
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5.2ohm is in the data you've loaded there. Did you generate the data somehow? or measure a real driver? Use what you have, and adjust when you have the real driver measurements.
At the very end of any project you'd always work with real data, measurements from the system you've built with the drivers you have acquired, to get as accurate data as possible into the program. Before that, if you are just zoning in for a concept, before you've built anything or purchased drivers, you inevitably work with "bad data", data that is not what you eventually get from your system as this data is measured by someone else in some other circumstances, or is result of some simulation, or from factory datasheets.
You can generate data with any simulation tool, many of which are included with VituixCAD like the enclosure tool or diffraction tool, but you can use any simulator that spits out data. And of course do measurements to get real data into the program. The program itself is as accurate as can be, but the results are only as good as the data you load in. You can work with "bad data" as well, very successfully so, as long as you have understanding what the data represents, how accurate it is to what is it you are using it for.
At the very end of any project you'd always work with real data, measurements from the system you've built with the drivers you have acquired, to get as accurate data as possible into the program. Before that, if you are just zoning in for a concept, before you've built anything or purchased drivers, you inevitably work with "bad data", data that is not what you eventually get from your system as this data is measured by someone else in some other circumstances, or is result of some simulation, or from factory datasheets.
You can generate data with any simulation tool, many of which are included with VituixCAD like the enclosure tool or diffraction tool, but you can use any simulator that spits out data. And of course do measurements to get real data into the program. The program itself is as accurate as can be, but the results are only as good as the data you load in. You can work with "bad data" as well, very successfully so, as long as you have understanding what the data represents, how accurate it is to what is it you are using it for.
I know that Vcad can be intimidating and the learning process difficult and slow.
Anyway,
Diffraction tool
Define your baffle and the position of the drivers (input the Sd value as well) in Diffraction tool: it's useful to load an frd file (full space field) and see how the response is modified by its position. Save the diffraction project and export the diffraction response: the response for the low frequency part should be at 10m distance while for the high freq. should be at 1m distance. Repeat the same procedure for mid and Tw (only full space part).
LF
HF
HF full space
Enclosure tool
Select the driver from the DB or, if not available, add your driver (+ button), select the type of cabinet (sealed, BR, etc.), check the desired alignment and load the diffraction resp. at 10m previously exported. Export the FR/ZR curves by pressing the SPL/Z buttons.
Merger tool
Load the LF file created by means of enclosure tool and the responses generated with the Diffraction tool, select the merging freq. (400-500Hz) and press merge.
And now the easy part, input the frd/zma file in the driver tab in the main program end create your xo: the LIB button can be useful to have xo models to use.
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First off, This is such a cool tool. Thank you for making it available to the community!
I've been following the guide for merging baffle step and enclosure models together, but after I perform the merge it's only showing frequencies up to the "high frequency part" (see the SPL chart I've attached). I feel like I'm probably missing something obvious?
Thanks!
I've been following the guide for merging baffle step and enclosure models together, but after I perform the merge it's only showing frequencies up to the "high frequency part" (see the SPL chart I've attached). I feel like I'm probably missing something obvious?
Thanks!
Attachments
Did you merge the measurements correctly, eventually also adjusting the level in the merger tool? Could you show a screenshot of merger window with your midwoofer?
I have a bug/problem in several of my simulations. I have the practice of starting a new VXP by saving an existing one to a new name and then modifying it, sometimes just the crossover. I often end up with the G(f) blocks not being able to find their MIR files.
Here is an example of the path to a file that fails
C:\Audio\Projects\Cardamons_2W\Cardamons_2W\Mir 8HX200_HF.txt
Here is the path that succeeds
C:\Audio\Projects\Cardamons_2W\Mir 8HX200_HF.txt
Notice that the failing path includes "Cardamons_2W" twice. At some point during my updates, that duplicate is inserted by the software, not by me. This might happen, for example, when I load a new set of driver polars. When I go back to the simulation, I get "can't be found" error messages. Invariably, the failing paths include that duplication of the working directory name.
Here is an example of the path to a file that fails
C:\Audio\Projects\Cardamons_2W\Cardamons_2W\Mir 8HX200_HF.txt
Here is the path that succeeds
C:\Audio\Projects\Cardamons_2W\Mir 8HX200_HF.txt
Notice that the failing path includes "Cardamons_2W" twice. At some point during my updates, that duplicate is inserted by the software, not by me. This might happen, for example, when I load a new set of driver polars. When I go back to the simulation, I get "can't be found" error messages. Invariably, the failing paths include that duplication of the working directory name.
I am trying to do the Frequency Response trace and then export the trace and import it to the enclosure tool. (Yes, skipping the diffraction tool for now) but I am running into issue. After importing the FRD, the FRD from the trace has the correct magnitude (the yellow curve is the FRD from the tracer tool, just below 90dB), but the FR calculated (Brown curve) goes all the way up to 170dB. Did I do something wrong? (I changed the input voltage to 0.1V so it shows both traces in the same Y-axis zoom)
