Forum Replies Created
21 February 2021 at 8:53 pm #320
Is this an electrical/digital measurement of the filter in a processor? Or an acoustic measurement of the filter applied to a loudspeaker?
The amount of pre-ringing in the filter depends on how filter filter is designed and what your goals are (e.g. phase linearisation).
Reply to this post then email the FIR Creator project and/or filter to our support address and we’ll take a look.
EA Support6 February 2021 at 7:16 am #317
We suspect the LIR is a complementary crossover where one channel is IIR filtered (e.g. HPF) and the other channel (with a LPF response) is created from the difference between the original input (with some small delay) and the filtered signal. When the two channels are added back together, only bulk delay is present and there isn’t any frequency varying phase shift.
We’ve been asked previously about implementing complementary crossovers in FIR Designer M and it’s on the todo list. To match LR’s LIR, we need to check with LR as to exactly what IIR filters they are using. Their paper suggests a 4th order IIR (for the HPF) and in our limited experience with this method, it results in approximately a 2nd order response on the complementary channel.
EA Support11 December 2020 at 7:12 am #307
It’s all there in the table on https://eclipseaudio.com/
Specific to making a FIR filter, the key difference is that FIR Designer doesn’t have any limits on the number of prototype Mag and Phase filters you can use and on the number of frequency bands or regions in the Auto Mag and Auto Phase tabs.
Also, FIR Designer has integrated measurement averaging and a few workflow helpers like Second View, Impedance viewing and no limits on the number of simultaneous project windows visible at any one time.
Maybe take a look at the FIR Designer 3 Overview video on
EA Support7 December 2020 at 11:29 pm #305
If IIR data from REW is exported as “filter settings,” then we (EA) need to either get the exact math from REW or take the time to match REW to known equations for IIR filters.
If IIR data from REW is exported as “filter coefficients,” then we could add the capability to load in the raw coefficients, but those IIR filters would not be editable or adjustable in FIR Designer. And the user would need to ensure the sample rates between REW and FIR Designer matched.7 December 2020 at 5:49 am #303
From the Export tab, FIR filters can be exported as text files and copied into the FIR Filter block or loaded using the Load button.
The IIR tab of FIR Designer can export raw coefficients for all IIR filters to a summary txt file, and the raw coefficients can be entered in this block.
EA Support30 November 2020 at 9:02 pm #290
WAV file import problems are common from REW since the IR peak is often well into the WAV file, rather than near the start. Better to use the IR TXT export. See REW on https://eclipseaudio.com/loudspeaker-measurements/
EA Support13 November 2020 at 7:58 am #280
If SMAART Di V2 has the SMAART API then yes, you can stream measurements from SMAART to FIR Designer and capture them. Maybe check the SMAART Preferences first.
You can test the SMAART streaming using our demo versions.
EA Support31 October 2020 at 9:40 pm #274
The IIR “Text file (Annotated TF)” export from all our products contains parameter settings and raw biquad coefficients (at the FIR Creator sample rate).
Is this the QSYS IIR block you are using?
We can implement a Qsys specific CSV export in a future update. In the meantime, you can make a CSV by taking the FIR Creator TXT file and copying the coefficients into a CSV file. For example
IIR Mode: General Sampling Rate: 48000 Hz HPF_BUTTERWORTH, 100.000 Hz, Order 2 b0:0.9907866979404248 b1:-1.9815733958808497 b2:0.9907866979404248 a0:1.0000000000000000 a1:-1.9814885091445689 a2:0.9816582826171297
0.9907866979404248, -1.9815733958808497, 0.9907866979404248, 1.0000000000000000, -1.9814885091445689, 0.9816582826171297
30 October 2020 at 6:08 am #272
- This reply was modified 4 months ago by EA Support.
FIR Creator can do impulse response correction for a measurement. Set the target phase to flat and use the Auto Phase tabs to push the response towards the target. For more details, see the FIR Designer 3 overview video at https://eclipseaudio.com/fir-filter-design-tutorial/
Note that correcting a response for a measurement from a single position can make the loudspeaker response worse at other positions. For a more consistent correction within the desired coverage, you can use the Averager tool to combine measurements from multiple angles.
From what I’ve read, David Gunness uses a combination of both measurements and horn modelling to generate the TQ FIR filters, so they’re not from measurements alone.
EA Support26 August 2020 at 7:37 am #268
Upgrade information is at https://eclipseaudio.com/upgrades/ I think you purchased about 10 days ago so you’ll get a full credit towards FIR Designer M. Note that FIR Designer M is a annual subscription product. For licensing matters, email us directly our contact us through https://eclipseaudio.com/contact/.
EA Support25 August 2020 at 10:27 pm #266
>> What is the best distribution for the sample rates? Lower sample rate for
>> the low channels and higher sample rate for the HF cannels?
Yes. For a 2-way, 24 kHz for the LF and 48 kHz for the HF. For a 3-way, 12 kHz for the LF, 24 kHz for the MF and 48 kHz for the HF.
>> That obviously means that I’II have to update to the very expensive FIR Designer M
>> to be able to work with the XP1, XP2,… Lake modules.
Like I said, the added complexity in the XP modules means it’s quite difficult to update FIR Creator EX and FIR Designer to work with them. We might update them in the future but we can’t give any time-frame. Also, the different sample rates on output channels don’t just affect the FIR filters; they also affect the IIR filters. FIR Creator EX and FIR Designer can’t display the summed response of all the channels – only FIR Designer M can do this.