room gain loudness

[pxr5]

friday night,
been working on these speakers for years,
response is flat 20-20 ( measured and theoretical)
low volume level all is ok,
turn up volume, bass too loud
room boost, ear loudness contour, these are the problems
need simple easy circuit
do you consider a cap of value? to give 100hz roll over in line with variable resistor ( not pot) to give volume control and loudness compensation will work? what i need is less bass as volume rises.
last step

[BillFitzmaurice]

Look at the Fletcher-Munson curves and you'll understand the problem: human hearing response is not linear with changes in level. Since the relative sensitivity of different frequencies across the audio bandwidth changes constantly with SPL there is no simple, easy circuit to maintain a constant response; it could be done with a digital EQ/RTA that was appropriately programmed to constantly alter the transfer function as a function of SPL.

[pxr5]

the fletchermunsoon i am familiar with
usually i turn it upside down to get an undersyanding of perceived freq response at given spl
at present have not ventured into pure digtal processing, but friend at allen and heath did years ago.
as my system stands, room gain gives flat shelf in bass from apr
ox 80hz to 20hz +4.5db
Thought if 6db/oct start 100hz would equate to -12 bd at 25 hz net reult -7.5db at full poweramp output leading to progression of design goal q=0.5 at flat response (((ie low volume(-6db))+4.5db room gain) -10db fletcher munson) =aprox -11.5db
what do ya say?
seems ok and simple

[pxr5]

thought of something
you propose an amplitude modulation correction
would,nt this sound like a compressor?

[BillFitzmaurice]

What you propose is just a variation of a loudness control. It works, but very simplistically, as accurate correction would take place at minimum at the octave level, and not as a broadband filter.

Digital RTA/EQs make corrections on a 1/3 octave bandwidth. They will do what you want but have to be reset for every level. They are purely EQ devices, not compressors. One that automatically recalibrates at every volume setting to maintain a constant perception of flat response at any volume is possible but to my knowledge not yet available.

[pxr5]

thanks,
seems like i'll have to do some reading and build a digi thing, in the meantime probably replace preamp with tone control (aaaah!). had a good music session last night, and really the sound is fine. just looking for something new to build i guess.

[johninCR]

"Measured flat 20-20K"...Where? In a chamber, outside, in room at your seating position?

I think first you need to get measurements at your listening position at different volume settings. This is imperative to understand what is really happening.

Have you experimented with speaker placement? Out from the wall vs against the wall will make a huge difference in bass response.

Do you have any acoustic treatments in your room?

This is a common pitfall of speaker builders. So much effort goes into getting a speaker perfect only to find out they never put it in the real world where room and placement have a huge effect on frequency response.

You've spent years getting your speakers right, but how much time getting your room right?

[Mos Fetish]

So, why place a great reliance on quasi-anechoic measurements? Are they really necessary other than to produce a set of measurements for comparison purposes?

The speakers are going to be used in room, so for the DIYer, why not always measure in room, right from the get-go?

Mos