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TAS5825M: Question regarding configuring a bandpass filter in the EQ section of the DSP with Speaker Characterization data imported

Part Number: TAS5825M

Hello,

We are using two TAS5825M devices in a 2.2 configuration. One of the amps is configured for stereo operation driving low/mid range speakers and the other amp is configured in mono, L&R channel summed to the Left channel driving a tweeter. I want to implement a Bandpass filter for the amp driving the low/mid frequency speakers. The corner frequencies will be approximately Low 70 Hz and High 3.5 kHz. I have used the PP-SALB-EVM and Speaker Learning App to characterize the low/mid frequency drivers and have imported this into the TAS5825M 2.2 configuration .ppc3 file.

The SPL data from the Smart Board Learning app is from 20 Hz to 20 kHz. I am having no problem implementing a high pass filter with a corner frequency of 70 Hz using the Smart Bass feature. The issue I am having is I am unable to create a low pass filter at 3.5 kHz due to the SPL data above 3.5 kHz up to 20 kHz. I have tried importing SPL data I measured using the CLIO audio measurement system. This normally works fine with a full 20 Hz to 20 kHz SPL data file. I have tried manually deleting SPL data above 3.5 kHz and it looks correct in the plot when I select the View SPL button. But it does not look correct in the EQ graph.

Here is an image of the EQ graph when importing the Speaker Characterization Data SPL

The large peak at 4,8 kHz in the Smart SPL data is preventing me from creating a low pass filter at 3.5 kHz

Here is an image of the SPL data I tried importing with the frequency data above 3.5 kHz manually deleted before importing:

When I select the Import button and then look at the EQ plot, it looks like this:

For some reason, the Smart SPL data extends out to 15-16 kHz and does not look correct.

Can you suggest a method to implement a 70 Hz to 3.5 kHz bandpass filter in the EQ DSP settings?

Thank you,

John

  • Hello,

    It looks like I did not correctly insert the screen images. Please see attached file for images.

    Thank you,

    John

    E2E - TAS5825M Bandpass EQ images.pdf

  • Hello John,

    Can you upload your PPC3 file. Also have you tried using the parametric algorithm for Smart EQ to modify the high frequency EQ generated by Smartamp.

    Best Regards,

    Luis

  • Hi Luis,

    Did you receive the PPC3 file I attached on Jun 24? Can you provide an update on this issue? I will be working on this soon and assistance with this issue would be really helpful.

    Thank you,

    John 

  • Hi Luis,

    TI FAE Garret Holt just told me it loos like the PPC3 file I tried to send to you was not properly attached. I have attached it as a .ZIP file this time. I will check with Garret to see if he can now see it is attached.

    Thank you,

    JohnJ5TW_DI3.zip

  • Hello John,

    What issues are you having with the 3.5khz low-pass filter where you say it's "preventing you" from creating a filter. Can you show me what filter you are trying to use and what issues you are having. You should be able to use one of the biquads to configure a low-pass, you might need to adjust the gain it defaults as, but you shouldn't be encountering any issue.

    Best Regards,

    Luis

  • Hello Luis,

    The issue I am having is when I import the SPL data from the PP-SALB-EVM or from a separate CLIO SPL data file, I am unable to create the 3.5 kHz low-pass filter. See Amp B, EQ section in the file I posted yesterday. Today, I deleted the SPL data from Amp in a copy of the PPC3 file I posted yesterday. I was then able to easily create a 3.5 kHz (actually, I set it to ~ 3.3 kHz) low-pass filter.I have attached a copy of the PPC3 where I have created the 3.3 kHz low-pass

    My issue is that I would like to use the SPL data to help with the EQ adjustments. But no matter what EQ biquad I use to implement this with the SPL data loaded, the EQ is unable to create a reasonable 3.3 kHz low-pass filter. I recommend you take a copy of the PPC3 file I posted yesterday and try to implement a 3.3 kHz low pass filter in Amp B in the EQ section.

    Also, you can see that in Amp A (which is for a tweeter), I have not loaded the SPL data, and it was also easy to create the bandpass filter we want for this speaker.

    I hope this clarifies the issue I am trying to resolve. Thank your for your help with this.

    John

  • Hello John,

    I uploaded the PPC3 with a lowpass filter on the 10th biquad and added a picture of how i configured it. Does this align with the lowpass you were trying to do?

    J5TW_DI3_lowpass.zip

    Best regards,

    Luis

  • Hi Luis,

    I have attached a PowerPoint presentation that provides details on the 3.4 kHz low-pass filter I am trying to implement. As I went through process of documenting and explain the issue for you, I believe I have explained to myself what I was questioning and how to address it! If you could read through this presentation and provide your thoughts on it, I would really appreciate it. Also, if think there is a better or alternative way to implement the high pass filter with the SPL data loaded, I would value any recommendations.

    Thanks for your help and let me know what you think.

    Regards,

    JohnTI_E2E_Lowpass_Filter_Case.zip

  • Hello John,

    I don't have any additional comments to your presentation. It's always difficult to get a perfect match of the equalizer and the compensated speaker response, but looking at your presentation your current solution addressed your requirements.

    Let me know if you have any more questions.

    Best regards,

    Luis