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Yes, the threshold for hearing audible phase shift on an analog equalizer can change significantly depending on the audio system and listening environment

. The audibility of the EQ's phase shift is influenced by factors beyond the EQ itself, including room acoustics, speaker design, playback volume, and the complexity of the audio material. 

How the audio system affects audibility

Room acoustics

  • Acoustic masking: In a typical listening room, sound reflections from walls, ceilings, and other surfaces create a complex web of constructive and destructive interference (a "phase soup"). This ambient phase distortion is far greater than what an analog EQ introduces, effectively masking the more subtle EQ-induced shifts.
  • Threshold shift: Because our ears are evolutionarily adapted to filter out the natural phase shifts caused by environmental reflections, the audible threshold for an EQ's phase shift is much higher in a normal room compared to a controlled, anechoic (echo-free) environment. 

Loudspeakers

  • Crossover effects: The crossovers in multi-driver speakers are a major source of phase shifts, as different frequencies are routed to different drivers (woofers, tweeters). The phase shifts caused by a speaker's own crossovers can easily dominate and obscure any shifts introduced by an external EQ. This is less of an issue with headphones or single-driver speakers.
  • Driver alignment: In multi-driver speakers, if the drivers are not perfectly time-aligned, it can create additional, audible phase distortion. Some high-end speakers, for instance, are designed to have all frequencies leave at the same time to ensure better phase coherence. 

Playback volume

  • Audibility increases with volume: Studies show that phase effects, particularly in the lower frequencies, become more noticeable at higher sound pressure levels (SPLs). If you are listening at low volumes, phase shifts are less likely to be audible, but they may become detectable when listening at higher, more intense levels. 

Headphones vs. speakers

  • Headphones offer higher sensitivity: Controlled studies have shown that phase distortion is more detectable on headphones than on loudspeakers in a normal room. Without the masking effect of a reflective room, the subtle changes introduced by an EQ's phase shift become more apparent. 

Complexity of the audio material

  • Musical content vs. test signals: Phase shift is generally inaudible on complex musical and speech signals. It is most easily detected with specific, simple test signals, such as square waves or tone bursts, and only under very controlled conditions. A phase shift that is obvious with a simple test tone may be completely lost in a dense mix. 

EQ-related factors that remain constant

While the audible threshold changes, the physical phase shift caused by a given analog EQ remains constant regardless of the audio system. The EQ's circuit design dictates the filter's minimum phase characteristics, which means the amplitude and phase response are inherently linked. What changes is the listener's ability to perceive that shift based on the overall context of the playback chain. 

tlcocks

Eric squires and other geniuses here (there are many, you guys are SMART), eat your hearts out

I use AI regularly now. I've used it for many things. It even correctly helped trouble shoot my recent streaming problem, electrical projects, dishwasher repair, etc...

Had a boat bilge pump problem. It not only diagnosed the problem correctly but supplied pictures and part numbers and where to order the parts. Amazing really.

BTW... I use it to search new music and similar artists. Far better than the search from Qobuz.

How smart an AI appears also depends on how the question is asked. If the right question is asked, the AI will provide more comprehensive responses, such as explaining the types of EQ and the issues they introduce or result in.

Broadly speaking, there are two main types of EQ in audio:

  1. Minimum-phase EQ (most analog and digital EQs)

    • Changes both amplitude and phase, but it does not create pre-ringing.

    • Boosts and cuts at certain frequencies introduce phase shift around those frequencies.

    • This is the “normal” EQ behavior you see in most hardware and software.

    • Any ringing or resonance happens only after the transient (post-ringing), which is how natural acoustic systems behave.

    • That’s why minimum-phase often sounds more “natural,” even though it alters phase.

  2. Linear-phase EQ

    • Changes amplitude but keeps phase response flat (no phase shift).

    • Achieved through digital signal processing (uses FIR filters).

    • Keeps phase flat, but to do that, it uses long FIR filters that are symmetric in time.

    • This symmetry causes pre-ringing (an artificial echo before the transient) and post-ringing.

    • Pre-ringing can make sharp attacks (like drums, piano, or plucked strings) sound smeared or unnatural, though in gentle EQ moves it’s often inaudible.

    • Useful in mixing/mastering when you want to avoid phase smearing (e.g., for parallel processing), but it introduces latency and sometimes pre-ringing artifacts.

👉 In short:

  • Minimum-phase = phase shift, no pre-ringing.

  • Linear-phase = no phase shift, but can have pre/post-ringing.

 

I asked AI a question about my desktop amp; got different answers if I used my phone vs computer - it was the ask on computer answer that was correct. Just asked some basic/factual questions about new integrated while it was being shipped - both answers totally wrong...so I simply don’t trust it - hard to know when it is very wrong...

AI is just as smart as the material it is referencing. I have found to follow up on the data links in order to see how the conclusion was reached. As we all know, there is a bunch 'junk' on the internet, and AI does not filter it unless you purposefully remove the data from the response. I have received significantly different AI recommendations once poor (or good) sources are removed from consideration.

It is kind of like history text books. Those from the 50's are much different from the 70's, 90's, and even today.