[EA Support]

EA Support

19 October 2022 at 6:36 pm #574

Hi Thomas,

The region around 150 Hz has fairly high phase slope at import and it looks like the tabs, prior to the Phase Adjust tab, have added additional phase slope; which looks to be from HP filtering. The result is a phase slope high enough that it’s marginal*, in the plotting, between showing a step between plot points (as in your screenshot) and wrap. Given that this freq region way out of band – it looks to be at approximately -60 dB relative to the passband – it’s safe to ignore.

* The plotting groups/averages the >16000 raw FFT data points into a smaller log frequency spaced set at approx. 1/96th oct spacing. Sometimes in this averaging, very high phase slope regions can go either way.

Best regards,
EA Support

[EA Support]

EA Support

16 October 2022 at 10:07 am #571

The Target response import loads almost all of our supported formats, including CSV. See Text and CSV on:

Loudspeaker Measurement Import File Formats

If your CSV is a magnitude curve, ensure your CSV file has 3 columns; frequency (Hz), mag (dB) and phase (degrees). The phase can be set to 0.0.

Best,
EA Support

[EA Support]

EA Support

27 September 2022 at 10:39 am #568

Noted. Thanks.

EA Support

[EA Support]

EA Support

13 September 2022 at 6:25 pm #565

Hi Lukas,

We’ll take a look but can’t promise any changes to address this. Odd handling of “.” in filenames is a problem shared by many apps; not just ours. All I can suggest for now is to not use “.” and instead use something else like the underscore. For example “filter_xyz_V0_2”. I do this myself in other apps.

Best regards,
EA Support

[EA Support]

EA Support

8 September 2022 at 11:18 am #563

>> Do you have a proper workflow how to achieve a 2- or 3-way System with a linear phase from about 100 Hz to 15 kHz?

The 2-way tutorial on the website shows how to use the FIR filtering, in particular the Auto Mag and Auto Phase, to force each loudspeaker driver toward a target response; which in your case would be linear-phase high-pass and low-pass responses.

>> Is there a possibility to show the step response of the hole speaker system?

Not in FIR Designer M at the moment. However the Wavelet display (in Second View) shows the response of the whole system and you can use this to confirm that the system is tending towards a symmetric, vertical line (which flares both sides at lower frequencies), indicating a pure impulse which, by definition, gives the step response you are looking for.

Best,
EA Support

[EA Support]

EA Support

7 September 2022 at 6:46 am #557

What you’re expecting is what happens when the LF rolloff is minimum phase. What is shown is what happens when the LF rolloff is linear-phase.

To investigate the effect more, run FIR Designer without any loudspeaker measurement on the Import tab, then put a HPF filter either on the IIR filters tab or the Mag Adjust tab. If using the Mag Adjust tab, try minimum and linear phase and watch the effect on the step response. Examples below.

BTW In your screenshots, check “Show FIR Filtered loudspeaker” to see all filtering applied to the measurement. This is what is used to create the step response.

Best regards,
EA Support

• This reply was modified 4 years, 1 month ago by EA Support.

[EA Support]

EA Support

6 September 2022 at 6:51 am #553

>> Unfortunately we experience Audio architect to not read the FIR (csv) file.
>> Audio Architect gives the error message “An Incorrect Number of coefficients were entered.”
>> Find attached csv file exported according to your instruction (897 samples) + the message from Audi architect.
>> Can you test my attached file?

It’s possible Crown have changed something and require a different number of coefficients. Either export the file again with fewer taps or edit the CSV file in a text editor to remove some lines. Repeat until the error message goes away. Note the last coefficients in the file are 0.0 anyway.

From your screenshot, Audio Architect is reading the coefficients and displaying them. It’s just the Apply button that triggers the error message.

(Your file loads correctly for us into “I-Tech HD series” and doesn’t give the error.)

>> Some questions.
>> In FIRd I have the sample rate set to 48kHz. Will this influence the exported coefficients?
>> Maybe the DSP in Crown HD amp need to have the same?

Changing the sample rate in FIR Designer will affect the values of the coefficients, but not the number of coefficients or taps.

As so what sample rate to use, that’s a question for Crown. It’s most likely 48 kHz.

Best,
EA Support

[EA Support]

EA Support

6 September 2022 at 6:43 am #552

Thanks for the screenshots. That’s exactly as expected and it’s caused by the linear phase LF rolloff in the filtered loudspeaker response. The only way to have a step response that steps up and stays up is to have a loudspeaker that has a flat response to DC.

To investigate the effect more, load FIR Designer without any loudspeaker measurement on the Import tab, then put a HPF filter either on the IIR filters tab or the Mag Adjust tab. If using the Mag Adjust tab, try minimum and linear phase and watch the effect on the step response.

Best regards,
EA Support

[EA Support]

EA Support

5 September 2022 at 7:29 am #546

Put your images on a file sharing tool like Dropbox or an image hosting website, then put the link in a post here using the “IMG” option. (A web search should show a few sites.) If you use Dropbox, copy the share link then change the URL ending to have raw=1. For example

https://www.dropbox.com/s/tg0cfa565aue4ak/zoo.jpg?raw=1

Best,
EA Support

[EA Support]

EA Support

4 September 2022 at 7:20 am #544

>> there does not seem to be a way to copy and paste the filter prototypes used to design a
>> target curve from the Mag sub-tab of the Target tab in workflow mode, to the Magnitude
>> Design tab of the Direct Design mode

That’s correct. The more common use case is the other way around; that is, design a target in direct design mode, save as a FDT file and import this on the main workflow Target tab.

>> It would be nice if we can have the FIR Designer target file export in addition to the
>> Export SMAART target file feature or an ability to copy filter prototypes between the two modes/tabs.

Note.

Best regards,
EA Support

[EA Support]

EA Support

1 September 2022 at 7:46 pm #541

Hi Thomas,

Long ramps in the filtered loudspeaker’s step response are usually from the LF rolloff. (Linearising the phase at very low frequencies requires a very long FIR filter.) Maybe post some screenshots of the step response and the filtered speaker’s mag/phase response.

Best regards,
EA Support

[EA Support]

EA Support

22 August 2022 at 5:41 pm #539

>> Biamp Tesira FIR Block doesn’t allow values +/- 1,
>> Is there a way to remove them during export?

On the FIR Designer export tab, there’s an “Output Gain (dB)” parameter. Use this to reduce the bulk level of the FIR filter by entering a negative dB value until the +/-1 warning goes away, then export.

Then elsewhere in the Biamp Tesira system, add a gain block to boost to recover the lost level (if you need to).

Best regards,
EA Support

[EA Support]

EA Support

10 August 2022 at 4:21 pm #533

Thanks very much for posting this.

We do plan to save the captured SMAART traces but we don’t have any ETA on when this will be ready.

Best,
EA Support

• This reply was modified 4 years, 2 months ago by EA Support.

[EA Support]

EA Support

7 August 2022 at 9:39 pm #531

Thanks. Just restart FIR Designer and it should trigger the link to 3.4.0 now.

Best,
EA Support

[EA Support]

EA Support

5 August 2022 at 7:47 am #528

Hi Bob,

We don’t have a reference. Here’s something (we posted on ProSoundWeb back in January) which may help.

Re the actual averaging modes

• Complex: This is full transfer function averaging. The phase of the cabinet is retained.
• Power (flat, zero phase): This power averages the magnitude only and discards the phase.
• Power (minimum phase): This power averages the magnitude only and discards the phase, then calculates the minimum phase response from the magnitude response. For a single driver in an anechoic chamber, the resulting phase should be very similar to the full Complex average. For a multi-way system with crossovers, this mode gives the cabinet phase response minus the additional or “excess” phase from crossovers.
• Power (complex phase): This power averages the magnitude only then combines this mag with the phase from the Complex averaging mode.
• Power (min. phase + Ref. excess phase): This is the same as the “Power (minimum phase)” mode but the excess phase from the Reference measurement is added in. (The Reference excess phase is the original phase minus the phase from a minimum-phase calculation from the Reference magnitude.) In a nutshell it’s calculating the excess or crossover related phase from the Reference measurement, then adding this crossover phase to a minimum-phase average of all the measurements.
• Power (with complex avg. excess phase): The magnitude is a power average and the phase is the excess phase only. This could be useful for isolating excess or crossover related phase and only correcting this phase. We’re not aware of anyone using this but it was easy to calculate so we thought it worth including.

Best regards,
EA Support