• Doco
  • ADAT user
  • Offline
  • Registered: 2018-04-03
  • Posts: 24

Topic: Is the ADI-2 EQ linear or minimal phase?

The manual does not seem to specify whether the EQ is minumum or linear phase.

2 Reply by MC

  • MC
  • MC
  • Administrator
  • Offline
  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,586

Re: Is the ADI-2 EQ linear or minimal phase?

Because that is not even a question. A linear phase EQ would need a lot of memory and cause a big latency of more than 10 ms. So if nothing is mentioned it is always minimum phase, all around the world.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2018-08-30
  • Posts: 7

Re: Is the ADI-2 EQ linear or minimal phase?

It says in SOS review of Genelec 8331 and 8341

https://www.soundonsound.com/reviews/genelec-ones

that

"Interestingly, all of the equalisation is configured using linear-phase filters so that the electrical input waveform translates as closely as possible to the generated acoustic wavefronts, and the processing latency is both very short (less than 4ms) and constant at all frequencies above 100Hz (it increases below that, in common with most loudspeaker designs)."

I am not expert. Therefore, I wonder, is this the same thing that you discuss above and what does it mean?

Br,
Tommi

4 Reply by Basken (edited by Basken 2018-09-04 15:02:04)

  • From: Copenhagen, DK
  • Registered: 2008-06-27
  • Posts: 91

Re: Is the ADI-2 EQ linear or minimal phase?

Tommi14 wrote:

It says in SOS review of Genelec 8331 and 8341

https://www.soundonsound.com/reviews/genelec-ones

that

"Interestingly, all of the equalisation is configured using linear-phase filters so that the electrical input waveform translates as closely as possible to the generated acoustic wavefronts [..]"

This is a somewhat misleading statement. Linear-phase filters are often used when you need to maintain a phase-relationship between two signals; a crossover would be an obvious application. However - linear-phase brings another problem to the table, which is pre-ringing, which can blur transients substantially at higher gain values / steeper slopes. In the case of the ADI eq is applied to a stereo-signal, and thus does not need to maintain a phase-relationship with anything - so there is (in my opinion as an audio-engineer) nothing to gain by using linear phase for general eq'ing; only potential problems to be had.

This video might be interesting:
https://www.youtube.com/watch?v=efKabAQQsPQ

Best,
Rune

EDIT:
.. and just to unpack that quote from SOS, they are referring to the speaker's built-in DSP being used for eq'ing the output of the speaker to be as flat as possible; think of it as "room-correction" for speakers. And - the price for this, audiowise, is all of the artifacts associated with (linear phase) eq'ing in general, which is not particularly desirable ..

Rune Borup @ FishCorp
Producer / Engineer / Composer
RayDAT > 2 x ADI-8 QS | AES+SPDIF > ADI-2 Pro