Overview

The miniDSP Flex HTx is an eight-in/eight-out high-resolution audio processor for home theater and multichannel audio. It integrates a 32-bit floating-point 400 MHz SHARC (ADSP-21489) and provides multichannel processing via HDMI eARC (LPCM), USB, and analog I/O. Key features include bass management, parametric EQ, crossovers, delay/gain, and optional Dirac Live (8-ch), all within a 1U form factor with an OLED display and 12 V trigger[1][2].

Scientific Validity

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Official APX555 data show 127 dB(A) SNR and 0.0001 % THD+N on the DAC path, with 120 dB/117 dB SINAD (balanced/unbalanced). The analog loop measures 114 dB/112 dB SINAD (TRS/RCA). eARC accepts 8-ch LPCM at 32–96 kHz, 16–24 bit. These figures exceed transparency thresholds by a wide margin[1][2]. Community reports indicate a four-chip ESS ES9017S sum/difference DAC topology[3].

Technology Level

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It combines true 8×8 analog I/O (RCA/TRS), multichannel USB (up to 7.1), and HDMI eARC (LPCM) with comprehensive PEQ/crossover/delay/gain. Firmware is upgradeable via Device Console[1][2][7].

Cost-Performance

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We surveyed cross-class alternatives that must not be inferior in both functionality (HDMI eARC multichannel LPCM → internal 8-ch DSP → analog outs) and measured linearity. StormAudio ISP Core 16 offers richer features (HDMI 2.1/eARC, 16 balanced outs, Dirac BC/ART) but independent pre-out measurements around ≈99 dB SINAD trail the HTx’s published 114 dB analog-loop / 120 dB DAC-path performance[4]. Lyngdorf MP-40 2.1 includes eARC and 16 balanced outs yet sits at 11,299 USD class pricing and does not show superior published linearity[5][6].
Since no cheaper device meets both criteria, HTx at 949 USD is the least-cost path to the target outcome and measurement bar; cost-performance is therefore maximal[1].

Reliability & Support

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Warranty is one year, with ongoing updates delivered via Device Console[1][7]. Software maturity should be monitored.

Rationality of Design Philosophy

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The design consolidates eARC LPCM ingress and multichannel DSP with objectively verified transparency in a compact chassis, reflecting a measurement-driven approach[1][2].

Advice

The HTx is ideal when you need verified-transparent multichannel processing, balanced integration, and analog input aggregation. While many AV processors add features, they often don’t surpass the HTx’s measured linearity; in this niche, the HTx offers exceptional performance per dollar[1][4][6].

References

[1] miniDSP, “miniDSP Flex HTx – Product Page” https://www.minidsp.com/products/ht-series/flex-htx
[2] miniDSP, “Flex HTx – User Manual” https://docs.minidsp.com/product-manuals/flex-htx/index.html
[3] miniDSP Community Forum, “Flex HTx type dac?” https://www.minidsp.com/community/threads/flex-htx-type-dac.22747/
[4] Audio Science Review, “StormAudio ISP 16 MK2 Review (AV Processor)” https://www.audiosciencereview.com/forum/index.php?threads/stormaudio-isp-16-mk2-review-av-processor.22251/
[5] Lyngdorf, “MP-40 2.1 – Product Page” https://lyngdorf.steinwaylyngdorf.com/lyngdorf-mp-40/
[6] Audio Science Review, “Lyngdorf MP-40 2.1 AV Processor Review” https://www.audiosciencereview.com/forum/index.php?threads/lyngdorf-mp-40-2-1-av-processor-review.54646/
[7] miniDSP, “Product Brief — Flex HTx (PDF)” https://www.minidsp.com/images/documents/Product%20Brief%20-%20miniDSP%20Flex%20HTx.pdf

(2025.9.7)