Sound meter + equalizer = problem solved?

I think it’s true. Digital room correction is even better. Are we just spinning our wheels and wasting time trying to solve the room acoustics/Fletcher Munson problem otherwise? Could audiophile dogma ie “don’t mess with the signal, dummy” just be completely wrong in practice? What were we thinking?


I love equalization, and fixes so many old recordings that sound terrible. The new recordings from 2010 and forwards seem to be OK flat, but the old stuff needs fixed.

It definitely has its place.

I’m using the equalizer capability of Plexamp app on my iPhone when streaming via airplay to my upstairs family room system, which has far from optimal acoustics,  and it brings that system much closer in sound to my 2 main systems downstairs.

Sometimes eq done right with an assist from a sound meter can be the easy path to glory for sure.

I used a white noise stream to measure the room response using decibel sound meter app on my iPhone then did the adjustments indicated needed in Plexamp and ta da, a big time step forward!

While both equalization and acoustic treatment address room problems, they are not interchangeable for the most part. Try fixing an echo with EQ or a dip at 1.5 kHz with acoustic panels. Company like Altitude insists that you address your room acoustic before using their class leading room equalization system. To get good bass, you will need to use both unless you’re blessed with an outstanding room. Purists look at both as shortcuts but they are wrong, those are necessary tools that should be in every audiophile arsenal. 

Notice to ALL... be careful with White Noise. Turned up too loud you can blow a tweeter because of equal db's at all frequencies. Better to use Pink Noise that has a roll-off of the highs.

1. Fletcher Munson, infrequent and temporary need.

Separate from basic match to your room. (Stupidly named ’Loudness’, it was for ’Lowness’ the opposite of loudness).

Fletcher Munson is a separate eq curve needed ONLY for very low listening, best if implemented automatically with volume reduction. If not automatic, then when listening at very low volume, manually raise the bass tone control, or engage the ’loudness’ circuit in your unit.

2. EQ to Match the Speakers to the Room. YES! Implemented HOW?

"In the Old Days":

1st a mono Radio, mono speaker with a mono amp; next, Stereo, add a second speaker with it’s own mono amp (thus dual mono). next add a preamp for moving magnet cartridges, Phono needs ’automatically engaged’ RIAA EQ and ’automatically engaged’ tape EQ if just a tape deck.

FM was Mono, then Armstrong solved Stereo FM. MPX EQ had to be added for FM Stereo, beginning with external mpx units, later MPX circuits added to preamp’s FM inputs.

Almost ALL that era’s speakers came with LEVEL controls,

i.e. 3 way had two level controls: ’Presence’ and ’Brilliance’.

You adjusted your SPEAKERS to both your space AND your ’taste’. Move them, re-adjust the LEVEL controls.

3. Next, Speakers no longer came with Level Controls,

thus Pre-amps were used to ’adjust the SIGNALS’ sent to the amps thus sent to the Speakers to adjust the sound for the space and/or your taste.

Basic signal adjustments included: balance; bass; treble controls.

Fully equipped preamps or receivers added:

Filters: Rumble; Phase (normal or reversed); automatic FM Muting between stations; Low Frequency Filter (acoustic feedback or noisy records); High Frequency (scratch or tape hiss); Some units included a ’Loudness’ (Fletcher Munson EQ) circuit, (mostly manual, automatically engaged Loudness came later).

Some units let you pre-match the separate component’s signals levels so the main volume would be the same when changing input devices.

Some units included MODE switches for: Stereo; Stereo Reverse; MONO; L+R to L; L+R to R; L to L+R; R to L+R

Later, more tone controls were added to some units, i.e. Treble. Mids, Bass. Or, more bands, like mini-equalizers in the preamp.

Next, separate Equalizers, with more bands to adjust individually, units had various # of bands, of various ranges of their assigned frequency.

Equalizers: Popular, then unpopular, then ’straight wire with gain’, which leaves you with zero adjustments in the space or your taste: (no controls in the speakers themselves, or to the signals sent to the amp/speakers).

Note: some modern hi-end speakers included EQ modules, located near but outside the speakers, to adjust the speakers to the space.


Well, let’s add room treatments!



Sound Meter: Yes.

Speaker/Signal Level Controls: YES

basic, more specific frequencies, a lot of frequencies. Depends on your space, and taste, and need for 'good enough' or perfection

EARS: yes, last,

find a preferred adjustment to the 'best flat' you achieve with meter/controls. Old dog, hear less highs, perhaps boost highs beyond what the meter 'hears'. Wife with ears that hear highs more than you do: cut the highs a bit.

Bass: seems weak, or muddy, no matter what the meter 'hears', boost or cut bass a bit.


There are two frequency responses:

- Direct to the listener

- Room response


Which one are you going to fix with EQ?  ... and therein is your quandary.

room acoustics/Fletcher Munson problem

I’m not even sure what this means. My advice is consistent here. A good sounding room and modest to no EQ is ideal, especially with subwoofers and trying to plumb the depths (16-40Hz) of output.

EQ is a lot better than nothing in rooms with tremendous bass peaks.

Room acoustics and EQ are not 100% equivalent, they do generally, both affect tonal balance. A very bright, reflective room can be made to sound tolerable by a basic tone control.

Treating the room to reduce mid-hi level reflections will make the bass appear, like a capsized ship coming out of the ocean at low tide.

There's also things you can't do with EQ.  Diffusion in between and the sides of speakers is very important for filling in and improving imaging.  A controlled resonance time makes your brain work less and ears to see more.  Bad room modes can only be fixed with a combination of EQ and bass traps.  EQ alone can't fix it.

(Lets the swarm crowd jump in here and take over the thread).  Swarmers, I'm talking in context of the OP's post.




Sorry should be clearer. Fletch/Munson and room acoustics are two different  cases, not just one, where equalization is a big part of the solution.

Digital room correction is like a spare tire, hopefully you never have to use it.

Yes it’s always better to not do a lot of things if not needed, like take prescription medicines, but if it’s needed then it’s needed because the results are better than the alternative.

I like a simple audio path as much as the next guy if that’s all that’s needed but that alone won’t cut it if the room acoustics are sub optimal. You might be able to fix the acoustics relatively easily in some cases but not in others. The point is there is that one extra option available that can help and is very easy and practical to apply….equalization and maybe even digital room correction. I am considering that perhaps as a good way to make my lesser room sound more like my good ones.

Equalization changes the speakers input into the listening space; room treatments change the output of the room to the listeners ears. They are both useful but totally different tools. Every time you move a speaker, schangecthe toe-in, raise them up  or down, you are changing their input into the room. It is every bit as much equalization as turning a knob, with the added complexity of changing the speakers acoustical interaction interactions with the space. Equalization cannot fix a bad room, ever. That requires acoustical treatment. 

I have EQ for my system (a Schiit Loki is there but not hooked up unless something really needs it) and rarely use it as all I generally need to (rarely) do is adjust my large, untreated room sounds great as it has furniture lots of crap in it. I guess I know from decades of experience how to set things up to suit my tastes, so there's no problem to solve.

I would change 'Sound Meter' to 'Personal Preference'. It does not matter how it measures, it matters how it sounds. A flat frequency response not necessarily is the perfect response for everyone, or for every music genre.

Isn’t equalization only as good as the instrument used to measure its impact? Something to think about.

@falconquest thats true but I find all that is needed is for the meter to be close to accurate to make my ears happy.  Decibel app on my iPhone works fine. 

@rudyb, when in doubt,  I consider flat to be the proper initial reference to work from. It need not be perfect and I may well tweak from there if needed. But at minimum it gives you the most useful starting point. Then you go from there, if needed. But in my case any changes I make from pseudo flat will be very minor. My two best systems downstairs are close enough. No EQ or room correction needed

@mapman True, you could of course perform a measurement and then use the Equalizer to reverse the speaker + room acoustics curve to first get it as flat as possible, and then fine tune to your preference from there.

You could also skip the first measurement and, with your eyes closed to rule out any bias you could give yourself from seeing what you are doing, tweak your Equalizer until you like it best. Would be fun to see if and how much the final settings differ.

Old news, but just showing my age....*creak* ;)

Was doing all this analog back in the ’80s’ with an Audio Control C-101 (series one, since that’s what appears to be what I ran...). Yes, ’room treatments’ would and could affect what one dealt with, but the whole sounded so much better after an afternoons’ worth of tweaking....

The modern digital versions and units ’spoil’ you....makes it just too easy.... *L*
Now I can take multiple readings from various locations and ’average’ them with a poke or three...tweak from there. And have some afternoon left over...

Most annoying thing about the 101 was the calibrated mic included. About the size of the average thumb, hard to make ’stay put’ in a mike stand....but had a long cord attached....

The ’pink noise’ had a ’burbuling’ quality that reminded me of a pot of roiling boiling water on the stove, but didn’t change the overall readings. The all LED display may not have given one the most finite take on the space, but would get you as close to ’flat’ without a major (for the era) expense for a ’pro’ unit.