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TAS2557EVM: TAS2557EVM + PP-SALB2-EVM usage problem with the speaker in vented box.

JIm Lai
Prodigy 20 points
Part Number: TAS2557EVM
Other Parts Discussed in Thread: TAS2557

Hi Sir 

Could you please explain that how do you deal with the speaker with vented box?

The PPC3 only shows the model with speaker in closed box as the first picture below.

Then our case need to use speaker in vented box, and the result showed that we have two F0 in the frequence response(following the second picutre).

Please help to check the way what we can use.

  • 0
    TI__Mastermind 19380 points

    Hi,

    Our TI experts are out of office today for US holiday, please be patient as responses are delayed.

  • 0
    TI__Guru** 102395 points

    Hi Jim,

    A second F0 is expected for a vented box speaker. Our speaker protection algorithm fully supports only single resonance speakers (closed box). For a vented box you can characterize the speaker as if it was a single F0, in this case ~600Hz, and fine tune the EQ to compensate for the second F0 using a notch or narrow-band filter. Unfortunately that second F0 won't be tracked with IV-sense but EQ can be used as a fixed limiter.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Hi Sir

    How do I know the exact second F0 value if I want to apply a fixed limiter by EQ?

    When I connect a speaker with vented box, I just can't reach the tuning stage since the excursion fitting error is too high. How could I use the EQ to protect speaker?

    Is it only the TAS2557 algorithm that does not support vented box speakers, do other new amps support?
    Or all TI Amps do not support either?
    Could you recommend which TI product can support algorithm with the vented box speaker?

    Thank you very much.

  • 0 in reply to JIm Lai
    TI__Guru** 102395 points

    Hi Jim,

    Let me discuss this project internally with our algorithm team. I may reach out over private message early next week to follow up with further details.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Hi Sir 

    Do you have any information updated? 

    Thank you

  • 0 in reply to JIm Lai
    TI__Guru** 102395 points

    Hi Jim,

    Sorry I lost track of this thread. Let me get the feedback to you within today/tomorrow.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Hi Sir

    Is there any good news?

  • 0 in reply to JIm Lai
    TI__Guru** 102395 points

    Hi Jim,

    Specifically for the characterization process issues you're having with the vented box, can you try by closing the opening temporarily only during characterization? After that we can check how the algorithm behaves on tracking the F0 but we may have to disable that feature (originally this feature is intended to detect leaks in the speaker box).
    Unfortunately a dedicated algorithm for ported or other types of speaker box is not supported at this time in any other of our amplifiers.

    Best regards,
    -Ivan Salazar
    Applications Engineer

  • 0 in reply to JIm Lai
    TI__Mastermind 19475 points

    Hi Jim, 

    I have tuned speakers with similar Impedance profiles. (2 resonance frequencies). for fitting the model during characterization you can work around this by excluding the second resonance from the model fit. For example from 200Hz-1100Hz.

    Since you are excluding a resonance frequency from the impedance and excursion model this means that the excursion protection cannot account for this. it will be best to measure the excursion with a laser to verify that it is still functioning as expected

    Regards,

    Arthur