Sample rates, hi-res and bit depth

Formats, recordings and ADCs

Answers on this topic

Does hi-res audio sound better than CD, and should I buy the 96k or the 44.1k release?
How can upscaling to 705.6/768 kHz improve sound if the recording has nothing above 22 kHz?

Everything he said on this topic (79)

One-line summaries in our words, oldest first. Each link opens the original.

2014-05-16Watts credits Hugo's 26,368 WTA taps for its timing, says more taps should help further, and suggests hi-res can underperform red-book because ADC out-of-band noise causes noise floor modulation. Head-Fi, May 2014
2014-06-01Watts says 44.1 kHz came from a Philips versus Sony dispute that Sony won, citing Watkinson's The Art of Digital Audio, which he calls his digital audio bible. Head-Fi, Jun 2014
2014-06-01Watts says higher rates improve timing but admit ADC noise-shaper HF noise causing noise floor modulation; Hugo's 26k-tap filter shrinks the timing gain; he considers a PCM HF filter. Head-Fi, Jun 2014
2014-06-01Watts says all files sound better on Hugo, but the relative balance between formats differs on DACs with WTA filters. Head-Fi, Jun 2014
2014-06-01Watts says the original recording rate is best, upsampled hi-res sounds awful, perfectly reconstructed 44.1 may beat hi-res due to ADC noise, and red-book can be stunning. Head-Fi, Jun 2014
2014-06-21Watts distinguishes pitch resolution from the 4uS inter-aural delay, and argues sample rates matter for transient timing, so a good interpolation filter makes CD sufficient. Head-Fi, Jun 2014
2014-06-26Watts advises sending 24/192 natively to Hugo despite its ADC noise-shaper noise, warning that PC sample-rate conversion degrades timing; one PC converting to 48 kHz sounded awful. Head-Fi, Jun 2014
2014-08-03Watts says DSD64 and DSD128 are severely limited formats, while DXD and Red Book are limited by implementation, and properly implemented Red Book will outperform DSD. article, Aug 2014
2014-08-03Watts says 99.99% of real-world audio is 44.1 or 48k and that will not change in the foreseeable future. article, Aug 2014
2015-03-04Watts says FIR filters have no simple dB/octave figure, more taps narrow the gap to hi-res, but poor SRC from 96 kHz masters cannot be undone, so recordings vary. Head-Fi, Mar 2015
2015-04-06Watts says 24/192 still sounds better than 44.1/16 on Hugo, but its 26,000-tap WTA filter makes the gap much smaller than on other DACs, and AAC can sound surprisingly good. Head-Fi, Apr 2015
2015-04-09Watts says comparing 192 with 44.1 also involves SRC, and his 96k Chandos Lark Ascending master sounded only slightly smoother than 44.1/16; the recording matters more than the format. Head-Fi, Apr 2015
2016-03-02Watts says 44.1/16 could in principle be near perfect, going from -330 to -350 dB noise shaping changed little, and 1M taps gives 16-bit sinc accuracy but needs costly FPGAs. Head-Fi, Mar 2016
2016-05-17Watts says hi-res generally beats Red Book but recording quality matters more than format, since many Red Book recordings outshine DXD ones; Davina will show what Red Book loses. Head-Fi, May 2016
2016-10-20Watts says 768/705.6 kHz 24-bit is best and 32 bits unnecessary, reports noise shaping beat Gaussian and triangular dither on the Blu Mk2 prototype, and Davina will study 44.1/16 losses. Head-Fi, Oct 2016
2017-01-09Watts says WTA processing is identical from 44.1 to 384 kHz, explains mounting the FPGA core switching regulator underneath to limit ground-plane noise, and Blu Mk2 needing 12A. Head-Fi, Jan 2017
2017-01-09Watts says 384/24 is distinguishable from 48/24 but recording method matters more, praises 1960s Decca recordings, calls the M scaler 'a great equalizer', and says Davina will measure losses. Head-Fi, Jan 2017
2017-01-23Watts says 16-bit coefficient accuracy has no bearing on recording bit depth: timing errors arise in interpolation, and an ideal sinc filter with 16-bit values needs over 1M taps. Head-Fi, Jan 2017
2017-01-28Watts explains peak error, why 16-bit accuracy needs about 1M taps, why doubling sample rate only halves conventional filters' error, and that taps are not the whole story. Head-Fi, Jan 2017
2017-01-29Watts says HD recordings benefit too but recording quality matters more than format, and a 16M-tap scaler would need cascaded FPGAs drawing 32A at 5V. Head-Fi, Jan 2017
2017-02-15Watts says few headphones need more power than Hugo gives, he added Hugo 2 filters for a softer option, and doubts digital EQ reaches the 350 dB needed for depth. Head-Fi, Feb 2017
2017-02-19Watts doubts ultrasonics matter for realism, crediting higher rates' gains to timing, plans 50 kHz microphones for Davina, and says transparent EQ would need 350 dB at 768 kHz. Head-Fi, Feb 2017
2017-03-25Watts suggests an Audacity FFT to check hi-res files: true 96/192 shows rising ADC noise-shaper noise, which he filters out to reduce noise floor modulation; upsampled files differ. Head-Fi, Mar 2017
2017-04-24Watts says FLAC does not support 705/768 kHz, so such files would need to be WAV, which should zip well. Head-Fi, Apr 2017
2017-04-27Watts says image upscaling like RAISR does not carry over to audio, where only transient timing must be recovered with longer filters, and plans Davina tests of 1M-tap losses. Head-Fi, Apr 2017
2017-06-10Watts says a native 768 kHz test recording from Chord's Japanese distributor sounded like M-scaled playback, unlike DXD so far, though its high ADC noise made DAVE's HF filter matter. Head-Fi, Jun 2017
2017-07-25Watts says the filters treat 16-bit and 24-bit data identically and cannot know whether PCM came from MP3, AAC or uncompressed files, though they know the sample rate. Head-Fi, Jul 2017
2017-08-21Watts says 32 kHz NICAM is obsolete; Hugo 2's SPDIF inputs still accept it, shown red (26 to 45.2 kHz), while USB supports only 44.1 to 768 kHz. Head-Fi, Aug 2017
2017-12-05Watts says the HF filter is for HD recordings, whose ADC out-of-band noise shaper noise adds noise floor modulation; filtering it sounds noticeably warmer. Head-Fi, Dec 2017
2017-12-11Watts says hi-res files need the same tap length, since doubling the sample rate cuts timing error area fourfold (2 bits) while the M scaler gives about a 16-bit improvement. Head-Fi, Dec 2017
2018-02-14Watts says Davina will let a 44.1 source be recorded at 705.6 as WAV, hoping 16-bit 705 kHz sounds as good as 24-bit; output bit size is an option. Head-Fi, Feb 2018
2018-02-24Watts says SRC and half-band decimation damage timing, triangular dither degrades depth, so he buys 96k originals; Davina's filters reach about -240 dB and will test bandlimiting and dither. Head-Fi, Feb 2018
2018-05-03Watts says pulse array was designed so every unit measures identically, attributes perceived break-in to the brain, notes a slight warming after ten minutes, and says 192k remains inaccurate. Head-Fi, May 2018
2018-06-09Watts says lower sample rates bother him less than sample rate conversion, which adds distortion and noise and degrades timing, so buy a 96k original over its 44.1 version. Head-Fi, Jun 2018
2018-06-10Watts says rock/pop originals are hard to get, often only MP3 which he refuses to buy; 99% of his purchases are classical from Chandos and Presto, preferring 96k masters. Head-Fi, Jun 2018
2018-09-14Watts advises the green filter: with 192k recordings the M scaler passes ADC noise up to 96 kHz, and the HF filter smooths sound by lowering noise floor modulation. Head-Fi, Sep 2018
2018-09-27Watts advises buying the original master, especially 96k, since SRC to 44.1 harms sound, but says 44.1 M scaled to 705k beats an unscaled 96k source. Head-Fi, Sep 2018
2018-12-13Watts contrasts CD's 22 microseconds with the brain's 4 microseconds, saying this explains why high definition and the WTA filter work, and says the brain infers bass from transients. Pursuit Perfect System 2:15
2019-01-26Watts says 192k recordings show only ADC noise above 30kHz, harmonics above 20k are inaudible, and hi-res helps by reducing timing uncertainty; Davina's noise starts above 500kHz. Head-Fi, Jan 2019
2019-02-15Watts says the HF filter is unaffected since it runs at 2048FS, and the M scaler passes ADC HF noise from 96k and 192k recordings like Hugo 2's WTA1. Head-Fi, Feb 2019
2019-03-25Watts says 768k works fine on the M scaler, and an M-scaled Red Book file sounds like a native 768k recording, unlike native 384k recordings. Head-Fi, Mar 2019
2019-03-26Watts says the M scaler passes 768k through, 768k sounds special against 384k, and 352.8/384k recordings he has heard sound little better than 44.1. Head-Fi, Mar 2019
2019-03-26Watts disagrees that 24-bit files benefit less from M scaling than 16-bit, saying reconstruction makes bit depth theoretically irrelevant; 24-bit files just start out better. Head-Fi, Mar 2019
2019-04-25Watts says the M scaler's 56-bit output is reduced to 24 bits by -301 dB noise shapers; triangular dither sounds worse, and non-integer SRC degrades sound. Head-Fi, Apr 2019
2019-06-13Watts says 96 kHz releases are better but not enormously; doubling sample rate only quarters the timing error, and M scaled CD beats 192k; Davina will test this. Head-Fi, Jun 2019
2019-06-15Watts says 96k beats 48k mainly because cheap half-band ADC decimation filters alias, that SRC to 44.1k adds distortion, and that only signal-dependent timing errors matter. Head-Fi, Jun 2019
2019-06-16Watts shows by a zero-crossing example why higher rates improve transient timing, says 705/768 kHz is needed, and says hi-res ADC noise causes noise floor modulation the HF filter reduces. Head-Fi, Jun 2019
2020-01-02Watts says he could not hear above 16 kHz in his last test, puts his limit near 15 kHz, and says higher rates are about timing, not sine waves. Passion for Sound 1:03
2020-01-02Watts says the brain resolves 4 microseconds, equivalent to 250 kHz, which bears on transient timing reconstruction, and that its timing accuracy is actually much finer than 4 microseconds. Passion for Sound 1:21
2020-01-10Watts says SPDIF is always 24 bits and USB 32 bits, with shorter words zero-padded, so Hugo 2 handles any bit depth automatically. Head-Fi, Jan 2020
2020-02-22Watts says truncating volume changes degrade depth and detail, dither is not transparent, only 705/768 kHz with 11th-order noise shaping works, DSP isn't transparent, and mastered files are best. Head-Fi, Feb 2020
2020-04-11Watts says the out-of-band noise comes from the data itself, especially in 96k and higher recordings where ADC noise-shaper noise increases. Head-Fi, Apr 2020
2020-05-24Watts says he gets most of his music from Presto, whose HD versions are authentic; an FFT shows whether a file was upsampled, and he has found no problems. Head-Fi, May 2020
2020-06-25Watts says his answer is complicated because Redbook CD is capable of extraordinarily good sound quality. Part-Time Audiophile 39:21
2020-06-25Watts says the benefit of 192 kHz is that it reduces the timing problem. Part-Time Audiophile 39:31
2020-06-25Watts says doubling the sample rate quarters the timing error, only 2 bits, while the M Scaler matches a sinc function to better than 16 bits to reconstruct timing. Part-Time Audiophile 39:38
2020-06-25Watts says an M scaled 44.1 kHz recording beats an unscaled 192 kHz one, PCM timing is fully recoverable with enough processing, and he wishes recordings were 768 kHz. Part-Time Audiophile 40:28
2020-06-25Watts says 192 versus 48 kHz is subtle but 768 kHz is a massive change, and Hugo One's filtering to 104 MHz made piano notes' starts and stops audible. Part-Time Audiophile 41:12
2020-09-11Watts advises buying the original-rate release, such as 96/24 over 44.1/16, since sample-rate conversion adds timing errors, and says 24-bit sounds better than 16-bit; he does not stream. Head-Fi, Sep 2020
2021-05-07Watts says system improvements now make poor recordings musically acceptable, and guesses 44.1/16 would sound better with a WTA filter in the case asked about. needs context Head-Fi, May 2021
2021-09-09Watts says a 768kHz signal has 256 times less transient error area than 48kHz, why higher rates sound better, and his WTA tuning found one sweet spot across recordings. Head-Fi, Sep 2021
2022-02-14Watts says the HF filter mainly removes noise and distortion in 96/192k recordings, helps 44.1k slightly, and Mojo 2's UHD DSP lets it stay on with flat response. Head-Fi, Feb 2022
2022-03-19Watts says each doubling of sample rate cuts the error area fourfold, 256 times less at 705 kHz, the 16FS sweet spot, and WTA2 is less tap-length sensitive than WTA1. MFG Audio Reviews 52:02
2022-03-19Watts says above 64FS timing becomes almost unimportant, 768 kHz recordings would make scalers unnecessary, and the one 768 kHz recording he heard sounds like an M Scaler. MFG Audio Reviews 52:53
2022-07-12Watts says 16/44 gains more from M scaling but 24/192 M scaled is closer to the original; his goal is 24/48 matching 24/192, needing transparent 24-bit re-quantization at 48 kHz. Head-Fi, Jul 2022
2022-09-18Watts says the filters remove noise above 20 kHz; old 96 and 192 kHz recordings have noise above 24 kHz, and filtering sounds warmer with less noise floor modulation. The Source AV 38:10
2023-02-05Watts says optical carries 24 bits at 192 kHz and asks how many recordings exceed that. Soundnews 50:23
2023-02-05Watts says he has no recordings beyond 24 bits and 192 kHz. needs context Soundnews 50:30
2023-03-17Watts advises buying the original-rate release since WTA cannot undo non-integer SRC, and says the 2A charger advice is about holding 5 V at Mojo 2's port. Head-Fi, Mar 2023
2023-08-24Watts says Arrival at 48k 24b on Qobuz sounded far better than his 16b 44.1k copy, blaming non-integer sample rate conversion common on soundtracks. Head-Fi, Aug 2023
2026-03-17Watts says information below the 16-bit level is encoded by dither or noise shaping, so 16-bit has 96 dB SNR yet an Audio Precision analyzer passes a -130 dB signal. ecoustics 7:02
2026-03-17Watts says 768 kHz recordings he has heard sound as if played through an M Scaler: very spacious, with tight, well-defined bass and good timbre variation. ecoustics 26:03
2026-03-17Watts says they are 24-bit 768 kHz. needs context ecoustics 26:31
2026-03-17Watts says pro engineers dislike 768 kHz 32-bit file sizes, but a very big company with archive recordings wants to archive at 768/32 so tape degradation stops mattering. ecoustics 26:46
2026-05-03Watts says the Pro ADC will offer lossless EQ and 768 kHz and 192 kHz recording; he wants studios to adopt 768 kHz, which needs FPGA post-processing. Audio Force 16:46
2026-10-14Watts says CD is good enough to enjoy music, with many 44.1 kHz 16-bit recordings he loves, but can be improved; his 768 kHz recordings get much closer to live. Part-Time Audiophile 48:08
2026-10-14Watts says CD sounds good but cannot close the gap to live unamplified sound, and that 768 kHz at 24 or 32 bit is the future. Part-Time Audiophile 48:52
2026-10-14Watts says 768 kHz, 24-bit or 32-bit, and that their mastering standard is 768 kHz, 32 bits. Part-Time Audiophile 49:31
2026-10-17Watts says Quartet returns lots, but the key question is the loss from decimating 768k to 48k and back, which needs a bank of test recordings through 2027. article, Oct 2026