Equalization

Most buy their speakers for the sound they prefer and don't need/want to add filters(tone controls), which can detract from sound quality, as well as interfere with internal crossovers in the speakers.
B

Hmm that is interesting.
So people use no filtering and just let the speakers speak on their own?

Yup.
I bought my Vandersteen Treo's for their sound and capabilities and incorporated amps/preamps/DAc's that work well with them.
For the most part, I have no desire to alter their sound reproduction. They reproduce music as it was recorded. Any deficiencies are mostly due to the recording.

There are some digital EQ systems out there to correct room response, but are rather expensive.
B

With limited exceptions, having tone controls/eq in the circuit is thought to cause a degree of corruption to the signal that takes the system a step away from the realism that is the end goal of a high end audio system.

I bought a used McIntosh Integrated amp that has bass and treble controls and I use them as needed.   I feel no shame in saying this.

@stereo5 
You are a liberated audiophile!

Indeed. It is one of these unfortunate audiophile myths that tone controls (or balance controls) degrade the sound and hence should be omitted. Makers of high margin audiophile electronics were only too happy to oblige as it saved them money.
The truth is that speakers are far from perfect, and their in-room response is even worse. Traditionally we had two types of tone controls to do something about this: the classic design by audio legend Peter Baxandall and the Tilt control by his friend and other audio legend Peter Walker. And even the Chromecast Audio streamer has recently been given a digital implementation of the Baxandal controls.
The limitation of these tone controls is that they cannot target quite narrow peaks and dips such as you encounter with in room response at lower frequencies. For that you need so-called parametric equalization. These days, with digital signal processing, that is easily achieved. One way is if you are using a computer as a source. Measure in-room response with the free REW software, generate a correction curve and apply that to the free Equalizer Apo software that you can install on the PC.  The same software can also be used to generate so called shelve filters to lift or depress response over larger parts of the spectrum. If you do not use a computer as your only source, you will need a miniDSP unit in your chain to apply that REW correction curve.
Alternatively, there are automatic systems, from the basic and very cheap Antimode 8033 for subwoofer equalization (room mode problems are biggest at the lowest frequencies), to the very advanced and expensive new Antimode X4 that will equalize not just the subs but also the main speakers, and act as a DAC and pre amplifier as well.

Most balance and frequency problems are actually produced by room anomalies. Comb filter effects, echos, first and second reflections, too much absorption, etc. A balanced program of tube traps, diffusers, resonators, Mpingo discs and other room treatments will get rid of the problem rather than covering it up. 🙈 First you need to map out the room including the 3D space to locate all sound pressure peaks that are at least 6 dB higher than the average SPL in the room when playing a test tone at moderate level. Of course there is the additional worry of the room walls flexing and vibrating like drum heads. More about that later.

This is great info.
Being a Musician (50yers+) and have done some live sound.
I have also recorded in many studios over the years is the reason I asked the question.
Studios go to extremes to "Tune' their monitors to the room and the room itself.
I took an RIAA recording course at Intermedia Sound in Boston.
Famous for Recording Aerosmith's first Album and other well known artists like Donna summer and the cars.
The Room was actually built on Truck Shock absorbers.
Although I have plenty of Music and Audio experience the Hi End Hi Fi Purist world is intriguing.I am learning a whole new concept of listening to music.

Unfortunately there is also quite a bit of snake oil being peddled. As for room acoustics and equalization, including some useful links: https://forum.audiogon.com/discussions/room-acoustics-10

bstbomber,  I still remember that I had to constantly adjust my old inexpensive receiver's controls.  It was either too bassy, too veiled, too bright etc.  Almost every CD needed some adjustment.  Today, with better source, amp and speakers I don't need to adjust anything.  I also noticed that the cheapest boom boxes have all sorts of controls including graphic equalizers. There is a reason for that.  Tone controls don't improve transparency and don't come for free.  Same goes for balance control, (that I don't need).  I like to listen to music the way it was intended.

In the most expensive manner possible.

Snake oil is good for the hobby. 🐍 It greases the wheels of progress and makes everything run smoother. Obviously not everyone is on board the progress train and that’s OK. 🚂

The best use of tone controls (which went out-of-fashion in high-end in the 70's) is to correct for the differing balances found in recordings. The Quad pre-amps had (have?) great ones.

@geoffkait , You kill me!

The best use of tone controls (which went out-of-fashion in high-end in the 70’s)

Yes they did, but from those that have it, this now has turned the tide on those old tone controls, and from reports here on A-gon, it sound very good. And it tunes in low bass, upper bass, midrange, and treble.
http://www.schiit.com/products/loki

Cheers George

What a great product, George! It was the nature of the filters in the Quads that made them so useful---shelving vs. roll-off, etc. I'm going to look further into the

I was in the Mapleshade exhibit with Pierre and Ron Bowman with Ron’s novel amp that had no tone controls OR volume control. The volume was preset electrically and less obtrusively. The resulting sound through the Nakamichi Dragon CD System and Gallo Ref. Speakers was VERY open and dynamic and smooth. I immediately jumped off the tone control train. 🚂 🏃🏻‍♂️ I doubt tone controls are a shortcut to Xanadu.

All this can now be done far more accurately in the digital domain. If one uses a computer as a source, the Equalizer Apo is perfect. As standalone units the various DSpeaker Antimode units are great.