Part Number: TAS5802
Other Parts Discussed in Thread: TAS2563, TAS2781
Subject: TAS5802: How to implement continuous Dynamic EQ (DEQ) / Dynamic Bass Extension across the entire input range?
Description:
Hello TI Audio Experts,
We are currently designing a smart speaker system utilizing the TAS5802 digital input Class-D amplifier. To maximize acoustic performance while ensuring system reliability, we intend to implement a Continuous Dynamic EQ (DEQ) / Dynamic Bass Extension feature that automatically adjusts the low-frequency response based on the real-time input signal level (ranging from 0 dBFS down to -36 dBFS).
Our target specification includes 4 discrete operational milestones to illustrate the intended behavior:
- 0 dBFS Case (Speaker/Amp Protection): Low-frequency attenuation starting from 150 Hz with a -12 dB/oct slope to protect the speaker driver from over-excursion and prevent amplifier clipping at maximum volume.
- -12 dBFS Case (Bypass): No extra signal processing is applied; the signal passes through with a flat baseline response.
- -24 dBFS Case (Low-Level Bass Boost): Low-frequency boost begins at the speaker's native attenuation onset frequency (100 Hz) down to a target low frequency of 60 Hz, achieving a maximum boost of +12 dB relative to the baseline.
- -36 dBFS Case (Ultra-Low-Level Bass Boost): Low-frequency boost begins at 100 Hz down to a target low frequency of 30 Hz, achieving a maximum boost of +24 dB relative to the baseline.
The conceptual curve of this behavior is illustrated in Figure 1 below:
[Figure 1: Conceptual_DEQ_Target_Response.png]
Crucial Requirement: While these 4 levels define our primary milestones, the EQ adjustment must be completely continuous and dynamic across the entire 0 to -36 dBFS spectrum. The filter characteristics must smoothly interpolate in real-time according to the input level envelope, rather than step-switching discretely between static profiles.
Current Status & Verification:
We have consulted with TI Korea regarding this requirement. The local support team informed us that while the TAS5802 supports static EQ configuration shifts per discrete level, it lacks a native, hardware-driven continuous "Dynamic EQ" processing block in its DSP pipeline.
To prove the feasibility of the target acoustic target curves, we have already successfully tested and verified the individual biquad profiles on a 6-ohm dummy load at discrete levels. As shown in Figure 2, the individual curves for both the woofer and tweeter signal paths perform exactly as intended when programmed statically:
[Figure 2: Measured_Discrete_EQ_Results.png]
Since individual control works perfectly, we would like to get a review from the TI HQ Audio DSP Architecture team to see how we can bridge this gap into a fully continuous dynamic system.
Questions for TI HQ Experts:
- Is there any native, undocumented block or advanced component within the TAS5802 DSP architecture (or inside PurePath Console 3) that can facilitate a truly continuous, signal-dependent Dynamic EQ / Dynamic Bass Extension?
- Can this continuous adaptation be achieved by creatively configuring the built-in Automatic Gain Limiter (AGL) or Dynamic Range Compressor (DRC) blocks (e.g., using specific sub-band sidechain routing)?
- Alternatively, if we implement an external host MCU to perform real-time envelope detection and dynamically recalculate/write the Biquad filter coefficients via I2C at runtime, is the TAS5802 architecture capable of handling rapid, continuous coefficient updates? If so, what is the maximum recommended update frequency over I2C to avoid audio artifacts such as clicks, pops, or zipper noise?
- If the TAS5802 cannot support this continuous requirement, are there any alternative TI Smart Amp parts (e.g., TAS2563, TAS2781, or higher-tier TAS6x series) or application notes you recommend that support continuous Dynamic Bass Extension out-of-the-box?
We would highly appreciate a deep technical review and guidance on how to implement this system successfully.
Thank you.
HR Kim @Hanwha Vision
