What does crossfeed do, which setting should I use, and why didn't the original Mojo have it?
Short answer
Crossfeed feeds some of each channel into the other, delayed and filtered, so headphones sound more like loudspeakers Head-Fi, Feb 2022Head-Fi, Apr 2021. Watts agreed there is no right or wrong setting Head-Fi, Nov 2017, but in posts from 2017 to 2023 his own headphone setting is the maximum, blue on Hugo 2 and Mojo 2 Head-Fi, Nov 2017Head-Fi, Apr 2021Head-Fi, Jan 2023. With Dave driving small loudspeakers he used setting 1 Head-Fi, Apr 2021. He said the original Mojo lacked it because of button count, battery life and his lesser enthusiasm then Head-Fi, Dec 2020.
Practical answer. For headphones, Watts's own practice in posts from 2017 to 2023 is crossfeed on at the maximum: blue on Hugo 2 (2017, 2019, 2020) and blue on Hugo 2 or Mojo 2 (2023) Head-Fi, Nov 2017Head-Fi, Jun 2019Head-Fi, Dec 2020Head-Fi, Jan 2023. In 2021 and 2023 he wrote that for headphones he always sets it to the maximum, without naming one product Head-Fi, Apr 2021Head-Fi, Jan 2023. He presents that as taste: "cross-feed has no right or wrong setting, that's why it's switchable" (Hugo 2 thread, November 2017) Head-Fi, Nov 2017.
What it does. In a February 2022 Mojo 2 thread post he described feeding part of one channel into the other, delayed and filtered for the skull absorbing high frequencies, so an extreme right signal appears at 30 degrees, not 90 degrees Head-Fi, Feb 2022. In June 2024 he said its whole purpose is to narrow the soundstage, so a recording panned hard left, center or right ends up at plus or minus 45 degrees, and that he finds it essential with headphones for width and depth Head-Fi, Jun 2024. In 2023 he said the math is identical to 1980s analog crossfeed Head-Fi, May 2023.
Which setting, by product
- Hugo (original). In 2014 he preferred maximum on a 1967 hard-panned album, saying it emulates a loudspeaker stage of about plus or minus 30 degrees Head-Fi, Aug 2014. In 2017 he said "crossfeed on Hugo 1 was only appropriate for older recordings" and that with normal recordings he heard no change in depth on Hugo 1 Head-Fi, Sep 2017Head-Fi, Sep 2017. In 2020 he said he had used it on Hugo 1 only for hard-panned 1960s recordings Head-Fi, Dec 2020.
- Hugo 2. In 2017 he said depth improves on all recordings with crossfeed set, and that he got sounds outside his head with regular recordings Head-Fi, Sep 2017Head-Fi, Sep 2017. In 2020 he said he uses it all the time, set to max Head-Fi, Dec 2020. In April 2017 he gave the settings as blue (max, 700 Hz, 4.5 dB), green (700 Hz, 6 dB) and red (min, 650 Hz, 9.5 dB) Head-Fi, Apr 2017, and in October 2017 a bass lift of 1.8 dB on full and 1 dB for red Head-Fi, Oct 2017.
- Dave. In 2015 he said crossfeed defaults to 0, which is off Head-Fi, Dec 2015. In February 2016 he said 0 is off, 1 is minimum and 3 is maximum, and that he prefers 3 as closer to a loudspeaker perspective Head-Fi, Feb 2016Head-Fi, Feb 2016. In April 2017 Dave-thread posts he first wrote that low frequencies are boosted by 1.5 dB without naming a setting Head-Fi, Apr 2017, then the next day gave bass lifts of about 1, 1.5 and 1.9 dB for settings 1 to 3 Head-Fi, Apr 2017; he has said the Hugo 2 code is identical to Dave's Head-Fi, Apr 2017. In 2018 he said the control stays live outside headphone mode, so you must unset it when going back to speakers Head-Fi, Feb 2018. In 2021, with Dave driving small office loudspeakers, he used setting 1 because they are a little too wide apart Head-Fi, Apr 2021Head-Fi, Apr 2021.
- Hugo TT 2. In 2018 he said headphone mode and DAC/amp modes each keep their own crossfeed setting Head-Fi, May 2018Head-Fi, Sep 2018. In 2022 he said its code is identical to Dave's, though the benefit may be more apparent on Dave Head-Fi, Jun 2022.
- Mojo 2. In January 2022 he said it has the same formula, coefficients and four settings as his other crossfeeds, implemented through biquads in the DSP core Darko.Audio 48:10. He gave blue as its maximum Head-Fi, Jan 2023. With EQ and crossfeed off, he said in 2022, the volume control receives bit-perfect data Head-Fi, Feb 2022. Quoting the handbook in 2023, he said a factory reset leaves crossfeed off Head-Fi, Mar 2023.
When to use less or none. In January 2023 he wrote that matching the image width heard directly under the microphone needs maximum, but that other recordings depend on the mix and personal preference, and modern recordings that avoid hard panning may need less Head-Fi, Jan 2023. In 2015 he agreed crossfeed does not make sense for binaural recordings Head-Fi, Dec 2015. Of his own 2022 Blumlein recordings he wrote: "If you listen on headphones use cross-feed set to max. Loudspeakers will be fine with no cross-feed." Head-Fi, Mar 2022. A month later he speculated that such recordings "perhaps" do not need crossfeed for the out-of-head feeling Head-Fi, Apr 2022.
Why the original Mojo did not have it. In December 2020 he gave the number of buttons, power dissipation limiting battery life, and that he was less keen on crossfeed when Mojo was designed; for him it went "from something nice (Hugo 1) to something essential (Hugo 2)" Head-Fi, Dec 2020. For Mojo 2 he said in 2022 that once a DSP core was in, crossfeed cost nothing in gate count Darko.Audio 47:26, and that he had been pushing for it on Mojo, with John Franks also wanting it Audio Force 5:22.
What he has not said. He does not recommend a setting for any particular headphone here, or give button sequences; see the handbook Head-Fi, Mar 2023.
Quotes
“cross-feed has no right or wrong setting, that's why it's switchable. I like blue simply because it sounds closer to speakers, but it's a personal preference.”2017-11-01 Head-Fi, Nov 2017
“for headphones I always set it to the maximum; but my office system (HMS and Dave) with Dave driving small loudspeakers I set it to 1, or the minimum”2021-04-16 Head-Fi, Apr 2021
“I only used cross-feed on annoying 60s recordings that panned hard left and right - ping-pong stereo. But with Hugo 2, I use it all the time”2020-12-04 Head-Fi, Dec 2020
“cross-feed wasn't included on Mojo for a number of reasons - number of buttons being one, and power dissipation being another, so limiting battery life.”2020-12-30 Head-Fi, Dec 2020
Dated positions
| When | Products | Position |
|---|---|---|
| 2014-08 to 2014-11 | Hugo (original) | He preferred crossfeed at max on a 1960s hard-panned album and said it is most noticeable on older recordings. Head-Fi, Aug 2014Head-Fi, Nov 2014 |
| 2015-12 to 2016-02 | DAVE | Dave's crossfeed defaults to 0 (off), settings run 1 (min) to 3 (max), and he preferred setting 3. Head-Fi, Dec 2015Head-Fi, Feb 2016Head-Fi, Feb 2016 |
| 2017-04 to 2017-11 | Hugo 2 | On Hugo 2 he said crossfeed improves depth on all recordings, unlike Hugo 1, and he sets blue (max) while calling the choice a personal preference. Head-Fi, Apr 2017Head-Fi, Sep 2017Head-Fi, Sep 2017Head-Fi, Nov 2017 |
| 2018 | DAVE, Hugo TT2 | Crossfeed stays available on Dave outside headphone mode, and Hugo TT 2 stores separate settings for headphone and DAC/amp modes. Head-Fi, Feb 2018Head-Fi, Sep 2018 |
| 2020-12 to 2021-04 | Hugo 2, DAVE, Mojo (original) | He uses crossfeed all the time on Hugo 2, uses setting 1 with Dave on small loudspeakers, and said the original Mojo lacked it because of buttons, power and his then lesser enthusiasm. Head-Fi, Dec 2020Head-Fi, Apr 2021Head-Fi, Dec 2020 |
| 2022-01 to 2022-04 | Mojo 2 | Mojo 2 has the same crossfeed formula and settings as his other designs, implemented through the DSP core, which he said added no gate-count cost. Darko.Audio 47:26Darko.Audio 48:10 |
| 2023-01 to 2024-06 | Mojo 2, Hugo 2, DAVE | He sets maximum with headphones, notes modern recordings may need less, and calls crossfeed essential with headphones. Head-Fi, Jan 2023Head-Fi, Jan 2023Head-Fi, Jun 2024 |
Caveats and open points
- Bass-lift figures come from two 2017 posts in different threads: about 1.9 dB at setting 3 (Dave thread, April, a day after a post giving 1.5 dB with no setting named) and 1.8 dB on full (Hugo 2 thread, October); both are reported.
- The 30 degree (2014, Hugo; 2022, Mojo 2 thread) and 45 degree (2024) width figures come from different posts and are not reconciled by him in this evidence.
- His personal headphone setting is stated per product for Hugo 2 and Mojo 2 (blue) and Dave (3, in 2016); he gives no personal setting specific to Hugo TT 2.
Topics: Crossfeed and spatial processing, Depth and soundstage