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Old 7th January 2020, 01:46 PM   #1741
kimmosto is offline kimmosto  Finland
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Quote:
Originally Posted by DBMandrake View Post
I don't understand this comment. Why should a 4th order Linkwitz Reily crossover necessarily cause such a severe impedance dip ?
I'm just guessing now: probably traced SPL curves without post processed conversion from half space to full space (missing BSC) has caused sensitivity error of 3...5 dB to woofer which could cause bad impedance issue if (traced) magnitude responses of mid or tweeter needs also lifting close to crossover frequency with high Q of LCR. This would be just illegal data used for simulation, though it's possible to select drivers in practice so that frequency response has dip(s) without small amplifying of driver's voltage with resonance of LCR.
Perhaps Oneminde could confirm has 4th order been an issue also with some actual and valid data.
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Old 7th January 2020, 02:26 PM   #1742
Oneminde is offline Oneminde  Sweden
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I have only played with imported data, no BSC, no consideration for cabinet and driver position etc so essentially doing everything I'm not suppose to do. It was a way to learn what the filter does. I am in the planing process of my first 4-way loudspeaker.
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Old 9th January 2020, 09:05 AM   #1743
kimmosto is offline kimmosto  Finland
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Rev. 2.0.34.0 (2020-01-09)

Auxiliary calculator : Time align
* Added manual scaling for Sum measurement, -1.0...+1.0 dB.
* Added auto scaling for Sum measurement; click dB label on the right side of value field.
* Error value and background color are updated also while manual adjustments.
* Improved LF delay solver to handle also bad initial values.
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Old 9th January 2020, 11:54 PM   #1744
drewrf is offline drewrf
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Direct me where to go if this isn't the correct thread for this, but it seems like it. I am running Vituix in a bootcamp environment on Windows 7 Pro. When I import an frd or zma file nothing happens. Files were created in Vituix with the tracing tool. I am at a loss as to what I am doing wrong. I don't have the "visible" checkboxes (see screenshot).
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Old 10th January 2020, 05:07 AM   #1745
kimmosto is offline kimmosto  Finland
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^I guess you have not added a wire from the generator to the driver? V2 does not make any connections to new projects.
See Tip 2
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Old 10th January 2020, 02:03 PM   #1746
drewrf is offline drewrf
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Quote:
Originally Posted by kimmosto View Post
^I guess you have not added a wire from the generator to the driver?Tip 2
I pulled them into Xsim and they displayed. Its likely the issue is with my bootcamp implementation. I have issues similar to this with other programs in the past. My bootcamp environment is shakey at best.

Thanks for the tip. I just wanted to make sure I wasn't missing anything obvious.
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Old 13th January 2020, 02:54 PM   #1747
Rob Dingen is offline Rob Dingen  Netherlands
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Hi Kimmo,

Is it possible to load an impulse response and truncate it and export it to a file that HFD software from Hypex can read?
Now I have to measure with HFD software and I have a Clio 12 setup which is much nicer to work with.

Rob
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Old 14th January 2020, 08:26 AM   #1748
kimmosto is offline kimmosto  Finland
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^Yes it is. MLSSA .txt is suitable file format, but you need to delete three rows from the beginning for HFD import, for example:
0
0.0208333333333333
262144
which are: just 0, sample interval in milliseconds and number of samples.

MLSSA .txt export is available in 'Convert IR to FR' (small export button on the right side of file list) and Impulse response window. The first one is able to export raw measurements only which is okay for small mids and tweeters. The last one is most suitable for post processed responses such as merged to LF near field sum * baffle effect response + HF far field response.

BUT HFD is not the best tool for designing crossover for multi-way from the beginning because acoustical off-axis, power & DI are not available. It could be valuable for fine tuning with measurement data, but important decisions should be done by full simulation. But this is common problem with filter designers of many...all dsp manufacturers.
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Old 14th January 2020, 05:12 PM   #1749
ralfk807 is offline ralfk807
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what would be the best way to model for floor reflections in the diffraction tool when the baffle is angled backwards (-10 deg from vertical plane)? I am building some floor standing speakers where the woofer is mounted fairly low to the ground however the entire enclosure is wedged by about 10 degrees.

also, are there any other locations that the tilted baffle would need to be accounted for? I have calculated the distances between drivers and will be placing them such that woofer voice coil is about the same distance as the tweeter from the listening position (i.e. tweeter will be further back and woofer forward due to the tilted baffle).
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Old 15th January 2020, 06:18 AM   #1750
kimmosto is offline kimmosto  Finland
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^Tilting is not possible with Diffraction tool so baffle is simulated in vertical position. Usually the lowest XO frequency is low compared to directivity of cone and box so simulation with tilt would not make significant difference.
Excess delay could cause small problem to phase response if elevation difference (Y coordinate) of driver and virtual microphone is high. Delay can be removed from baffle effect response with Minimum phase A function of Calculator tool.

Probably the biggest uncertainty is defining attenuation of floor reflection. I think perfect reflection producing 6 dB gain is not the best option producing too low "average" pressure for woofer. About "double power" could be more correct estimation so one option is to attenuate floor reflection until diffraction simulation produces total baffle step of 3 dB, and then axial response is designed flat with the main program.
Second option is to leave floor reflection unchecked and reduce axial distance until total baffle step is about 3 dB, and then axial response is designed flat with the main program.
Third option is to leave floor reflection unchecked and simulate diffraction to the longest possible listening distance e.g. 5000 mm and design axial and power responses with the main program so that power response stays constant (flat horizontal) below the lowest crossover frequency. This is what I would probably do because method takes into account also directivity of LF radiator. Inroom SPL at listening spot could be a bit too high at LF, but correct level is subjective anyway and depending on listening environment and setup i.e. speaker & listener locations.

Driver measurements 0-180 deg according instructions; mic perpendicular to driver (speaker tilted vertically while off-axis measurement sequencies). Drivers located to simulation according final reality i.e. Z coordinate and T tilt varies for each driver.

And finally, I would not locate single woofer very close to floor
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