How to do EQ right?

[MaxwellsEq]

Interesting reply, so according to this view the 4) tone controls is kind of giving a specific "twist" of the music based on how you feel on that day. I liked that. Although I understand that are people that they like the to get the original signal as pure as possible.

It all depends on implementation. The best I ever came across was the tilt control on Quad preamplifiers.

There's no free lunch. When you change something in the frequency domain, you change something in the time domain. This means phase change. Some people consider that phase changes in the electronics should be kept to a minimum. Tone controls can be quite gentle in their application with only a few dBs of boost or cut, and only at the frequency extremes. Others can be too coarse, with corner frequencies too close to key mid frequencies.

But, with PEQ, you pick the frequency, you pick the boost or cut and how wide or narrow the impact. This is considerably better than tone controls.

 

[alaios]

I do not know about the old fashion. I am just 40 and I like the stuff to me EQ is an extremely important tool. I also find tune controls important as it can make sound to bit different based on my mood. It is like the days that you find yourself adding a bit more milk to your coffee mug. It is just a tool and is our choice when to choose to use it

 

[MaxwellsEq]

It is just a tool and is our choice when to choose to use i

This is, of course correct. But all tools require knowledge and training / skill. People here are helping with your knowledge. Tone controls are OK, but a much less refined tool than PEQ. But PEQ needs more skill and knowledge to operate. The difference is that gentle digital PEQ normally has less negative side effects than tone controls.

 

[Keith_W]

Hope this was interesting and (even better) useful!

You write well. You should write more

 

[gnarly]

From my tests, Dirac Live "Phase alignment" comes mainly from use of minimum-phase filters (which also solve room resonances) and constant delays (to time align loudspeakers at different distances); and speaker driver alignment comes from use of all-pass filters (a type of non-causal EQ normally implemented as FIR) to counteract crossover filter phase wrap. These are all types of EQ filters.

I've only had Dirac Live (room correction suite for a few months, and only ran it two times on a stereo setup.
So I'm only about 80-90% confident in the following conclusions I made, on how Dirac Live appears work.

After generating the room correction files, I ran transfer functions where the PC input stream to Dirac was the reference channel,
and the Dirac PC output was the measurement channel. Line level transfer functions to see exactly what Dirac was doing.

The first speaker, Left appeared to have only minimum phase corrections.
The Right speaker had both minimum phase and mixed phase corrections (maximum phase was obvious).

So it appears to me, Dirac chooses one for pure minimum phase work, and then matches the other with whatever it takes.
It was also obvious a fair amount of FIR was in play, just due to delay between reference and measurement.
I forget now what the delay was, but remember it was close to the same of both Left and Right.
Which makes me think the Left channel's apparent minimum phase only corrections, were IIR embedded in FIR.