Fletcher Munson Curve verses a flat frequency response.

[Chris A]

No these Revels speakers have a very flat frequency response.

You're talking about amplitude response (only). What is the difference between the loudspeakers you mention in terms of their phase response? One loudspeaker having only good looking amplitude response plots doesn't mean that it compared to other loudspeaker types will subjectively sound the same or have as much bass response.

As I mentioned above, adding "loudness curve" EQ is a separate task to compensate for listening at lower or higher mean SPL than the mastering guy used for each music track. That is not something assignable to a loudspeaker itself.

Chris

 

[90sNintendoKid]

I've seen a few threads about Audessey Dynamic EQ and Loudness in Camilla DSP.

I tried something out today on my Android phone using Poweramp Equaliser. I loaded the EQ for my Meze Albas and I increased the bass and treble by 10 percent. I noticed I was listening at 75 percent of my usual volume or less.

I'm going to investigate what the Camilla DSP Loudness implementation is like.

 

[Sal1950]

Why did that feature disappear on modern amplifiers? Don't people listen at lower volumes anymore?
I find it convenient to press a loudness/contour button when I'm listening at low volumes anyway.

I fully agree.
The "audiophile" belief in what's a proper approach for something like a preamp section whether separate component or integrated in receiver, etc has changed over the years. Going back to the beginings of Hi Fi gear the idea of included tone controls was considered desirable, some going further with available multi-band equalization, things like loudness buttons, switchable high and low cut filters, more were the norm.
Then IIRC somewhere around the mid - late 80s -90s all EQ slowly fell out of favor, the thinking (sometimes correctly) that the FR control circuits introduced unacceptable levels of distortion, etc. We slowly went from very full featured preamps to slowly excluding much or all of the control circuits, Often going so far as fully passive preamp stages. Since the 2000's we've now returned to a more reasonable, sensible approach, specially since much of the EQ can be accomplished in the digital domain with little to no worry of unwanted distortion and other audible issues creeping into the designs. DRC has been a revolution for Hi Fi, specially for multich rigs where getting bass control and arival timing of the many speakers at very unequal distance to the listening chair better controlled.
The future so bright, I gotta wear shades.

 

[DVDdoug]

What is the difference between the loudspeakers you mention in terms of their phase response?

Phase-shamze. Does Phase Distortion/Shift Matter in Audio? (no*) (YouTube video by Amir).

A phase difference between the left & right speakers, or between the main speakers and the subwoofer can make a difference.

Speakers tend to foul-up the phase by a lot.

The crossover tends to create a phase-lag in the lower frequency driver at the crossover frequency and a a phase-lead in the higher frequency driver. It's often a 90 degree shift, which would put the drivers 180 degrees out-ot-phase at the crossover frequency. And that would create a dip where the soundwaves combine and cancel. To correct that, the connections to the tweeter (or midrange) are often reversed, reversing the polarity for a 180 degree phase shift. That puts them back in-phase at the crossover frequency, and the tweeter (or midrange) is inverted 180 degrees.

 

[Barrelhouse Solly]

Yamaha used to have (maybe still has) these interesting variable loudness controls that shifted the Fletcher-Munson curve depending on the volume level—decrease the volume and the bass increases proportionally. I recall using one of the Yamaha receivers with this control, much better than a typical "loudness" button. I like bass and I probably like it too much, so I like more of it as the level goes down.

My first set of hifi gear included a '50s Fisher mono tuner-preamp that included a variable loudness contour control. Other cool features were a magic eye tube and a whole bunch of EQ curves for '78s. I really miss the magic eye.

 

[Sal1950]

I really miss the magic eye.

Magic eyes were just So Kool !
Wish we had stuff like that today.
Or the Marantz gear with an oscilloscope, tube gear without the usual tube sound, that would be awesome.

 

[90sNintendoKid]

I setup CamillaDSP with a Wiim Ultra as the source and Fosi Audio K7, applied EQ for my headphones, also setup a Loudness filter and I absolutely enjoyed the results. My only problem now is how I set the reference level for the loudness filter and sync the CDSP volume and headphone amp volume. I think I may have to get a Minidsp Ears.........

I may make a thread to document my experiment with this. I followed @mdsimon2's excellent CamillaDSP on a Raspberry Pi github repo and also setup CamillaDSP set rate and updated the C code to use the latest view on chunk sizes.