Listening fatigue

Comb filter effects (time domain errors) can be blamed for a lot of the distortion as the volume is turned up since the comb filter effects in the room are a function of the sound pressure in the room. Isolating all components from vibration induced distortion, use of tube dampers, damping CD transport, damping capacitors, colorizing CDs, demagnetizing cables and CDs, suspending cables, all of these things will reduce distortion at higher volumes. Ironically, while digital promises huge improvements over analog for dynamic range and signal to noise ratio, off the shelf digital frequently sounds compressed, noisy, distorted, not to mention thin, tinny, threadbare, two dimensional and congealed.

Fantastic summary as usual, Atmasphere!

Here is some additional information on lister fatigue that I have copied from the Teck Talk forum:

"Listener fatigue is nearly always a consequence of distortion.

Two distortion sources are IM distortion and odd-ordered harmonic distortion. Both are known to be irritating to the human ear- and this has been known since the early 1950s.

What is less understood is some of the studies of the human ear that have occurred since then that relates directly to listener fatigue.

One of those things is that the ear/brain system uses odd ordered harmonics to sort out how loud a sound is. To do this it is very sensitive to the presence of odd ordered harmonics. Audiophiles have terms for the presence of trace amounts (less than 0.01%): hard, harsh, bright, etc.

This is why two stereo pieces can measure flat on the test bench but one might sound bright while the other does not.

In addition it is useful to know that the ear is tuned to birdsong frequencies. Knowing that makes its easier to understand how the ear can be that sensitive to the presence of the 5th, 7th or 9th harmonics.

The ear translates distortion as tonality. A 2nd harmonic is interpreted as warmth, a 7th as brightness.

IM (Intermodulation Distortion) is a form of harmonic distortion that the ear usually translates as brightness. This is where two more more tones can interact in the stereo system to produce other frequencies, the sums and differences of the tones involved. It is caused by non-linearities in the system, any place where the tones can interact, such as a feedback node in an amplifier, poor power supply design or a breakup in a speaker cone.

There is a special form of IM distortion called inharmonic distortion that only occurs in digital products (good luck looking for the specs on that- most manufacturers don't publish the numbers). These are intermodulations between a fundamental frequency and the scan frequency of the recording rather than harmonics based on the fundamental tone as is encountered in analog recordings. The ear treats these as brightness as well.

There is a tipping point in the human hearing perceptual system where the ear will favor distortion as tonality over actual frequency response errors. As a result is is often more important to have low distortion rather than flat frequency response. For this reason its usually best to reduce the types of distortion that the ear finds most objectionable and noticeable before going after frequency response errors."

Listening fatigue can be either the result of too much
volume overwhelming the sensitivity of your ears, or there
may be components within the stereo system that just don't
work well with the overall system. For me the biggest culprit has been my choice of speakers. Heavy and very tall tower speakers by their build nature can physically overpower a stereo room because they are meant for a large room setting and their sonic signature is just too much for the ears to handle for any length of time. I have also noticed sharpness, shrill, and bright sounding in a speaker to be factors making listening a short time stint. Given that all components are of equal quality, a good speaker blends well with the entire system allowing for music to be enjoyed to hold a lisener's interest at low soft levels or in varied moments of loudness.

Ditto the early reflections. Added bonus: by minimizing early reflections later reflections are minimized geometrically. Minimizing corner reflections and slap echo is also important. But I would avoid Sonex like the plague.

If you get rid of early reflections, some imaging information will seem to be lost. This is because the ear/brain system uses early reflections to assist in image location.

The sound travel 1000 feet per second. You can hear the sound from speakers for 4th of a second and the sound will travel 250 feet. Your room is 15 x 20. Every sounds from speakers will bounce walls and hit your ears more than 10 times. That's no good! I don’t know if your room is sonically live or dead. If it’s live, you need to tame your room. You need to reduce the sound reflection.

I recommend 1) Madisound Dampers: Felt Defraction Ring for Tweeters. Put these $2/each felt ring on tweeters of Mites. These dampers will reduce some early reflection sound from speaker cabinets. 2) If the room is live, put some Auralex or sound absorbers on walls. If possible put some damper on the ceiling too. If your wife think they are ugly, put some pretty curtains on walls instead. Good luck!

Agree that clipping is a likely significant factor with most any SS amp of that power rating and most better modern smaller speakers.

Harri009 makes a very good point!

Ah, that insidious crescendo! I think you're right.

I would say you are clipping your amp. Your amp is only rated at 50w into 4 ohms. Your speakers are 87db/m. So if seated 15 ft away that calculates to about 96db. This leaves nothing for dynamics which can EAT power. Like I said, if its mainly at higher SPL's I would bet your clipping the amp.

I find to much energy at the frequency extremes can cause fatigue , to much bass , to much treble , is your system balanced and neutral ?

OP-

you may need additional sound-proofing of your listening space.

Happy Listening!

In my experience with Mani 2s I once owned, the Totems are only going to play so loud before they start to compress. That may be what you are hearing at loud volumes even though is seems you have sufficient power to drive them.

Thanks, everyone, for weighing in. I played around more with the position of the sub and I think I'm on the right track – a foot and a half seems to make a lot of difference in that room. Soffit traps, no, but crown molding, yes – she might go for that, Davehrab.

I have no experience with the Mite, but judging by this measurement which I found from a Mite owner, it's easy to see what would be causing the fatigue - the top end is tipped up significantly, probably intentionally to give the sensation of more air and detail.

http://harmonicsreview.files.wordpress.com/2010/02/totem-mite-fr.png

Another thing that is well-known for causing listener fatigue is odd-ordered harmonics in trace amounts, something that is common to most transistor gear.

This will get more pronounced as volume is increased.

The reason is that the ear uses odd ordered harmonics to figure out how loud a sound is! If the equipment makes odd ordered harmonics it will come off as louder and brighter than the measurements would suggest.

Our ears are more sensitive to these harmonics than they are to human vocal frequencies- by quite a wide margin!

To get rid of the odd ordered harmonics, you might try introducing some tube electronics into the signal chain. Tubes are more linear, and make less odd ordered harmonics as a result. This is why they sound smoother in most cases.

Remove the sub for a few days,and see if that works,sometimes subs cause more problems than they are worth.

Is there a low pass filter on the sub? Where is it set? Is it self powered? What volume are you playing it at? Setting a self powered sub's low pass filter too high and especially too loud will definitely cause fatigue with any component set-up. You'll probably cure the problem by setting the system up "flat".

My first instinct is to agree with Elizabeth's guess that the sub is the first culprit.

Funny, I experienced fatigue just a couple of nights ago for the first time in ages. I was listening to vinyl at a very reasonable volume.

"as always, YMMV"

I played in bands off and on for years and I would never (now, at least) want to recreate those levels of sound pressure in my private listening. Those guys at the soundboard have made themselves deaf and are gradually doing the same to you.

I hate to throw cold water on a fellow file but...I am 54 and have been through vinyl to cd to download to vinyl. I have had (used, so I usually could sell with not much loss) Wadia's best/a dcs stack/audioaero etc. No matter what I did fatigue always set in at higher volumes and I found myself in higher volumes to get the experience I craved. I finally bit the bullet and went back to vinyl. I have never felt fatigue since. Some crackles on 1.00 records but never fatigue. Neil Young once said "digital feels like hail." Look at the ads for digital equipment. They spend a page just explaining the clocking....Hi fidelity requires simplicity I believe. Best of luck.

Its also possible that if the gear is new it will settle into a smoother presentation over time as things break in. You might want to play things a bit louder than otherwise in the meantime to help that process along faster perhaps, if possible.

Always tweak setup of what you have to optimize it fist before changing anything!

Try listening with less direct exposure to the tweeter output.

Try listening off axis from the tweeters and see if the fatigue is reduced or eliminated.

If it is, try setting up speakers so tweeters fire to either side of your listening position and not as directly at you, so you are listening at a similar off-axis angle.

Then play with the distance between speakers and distances to rear and side walls to avoid early reflections until you hear a nice balance of tonality without fatigue, soundstage and imaging, and bass levels.

Definitely experiment with ics first,then speaker cable.It can make a huge improvement.You absolutely do not have to spend mega $ to hear large improvements.Check out Bluejeans cables for a start.They have a thirty day trial period, so no risk.

One of the most closely guarded secrets in all of audio is why the distortion rises so much as the volume is turned up. Now, I'm not saying that some of the distortion we hear at higher volumes is produced by distortion in the speakers, distortion in the electronics and/or distortion produced by room acoustics anomalies such as comb filter effect. The problem is that even when those fairly obvious potential causes of distortion at higher volumes have been addressed there is still a significant amount of distortion at higher volumes. It's a little bit analogous to the background microwave radiation - we can eliminate all the other potential sources of noise in the universe, so the residual noise must be from the Big Bang! So, where does this distortion come from, this distortion that's not related to the audio system electronics, or the room acoustics, or anything in the audio system cabling, or house wiring? Hint: it has to do with why the sound gets better when all telephone books are removed from the house. And why the sound gets better when all CDs are stored Vertically instead of Horizontally. And why taking cell phones out of the house improves the sound.

Defeating first reflections usually improves sound stage and imaging by reduce the amplitude of the reflected wave that arrives at your ear shortly after the primary wave

Fatigue is usually caused by long decay or extended RT60 times causing the note to linger in your listening room much longer than it should

When energy traveling up the walls meets the energy traveling along the ceiling and floor at the Wall/Ceiling/Floor interfaces ... it’s is combined and the high frequency ringing is extended causing the fatigue

To reduce or defeat the ringing you must trap it at the wall ceiling interface with acoustical treatments like a soffit trap (GIK) or Sound Flags (ASC) .. I use Sound Flags around the perimeter of my 16x27 room

If acoustical treatments are a no go in the bed room you can install 6 or 8 inch crown molding all around the room’s perimeter and she’ll never suspect anything

The crown molding breaks the hard 90 degree angle at the wall ceiling interface with it’s gentle curve and works more to diffuse and redirect the energy in a wider band as opposed to trying to absorb it like a fiberglass trap would .. either will work it a matter of what is acceptable in the bedroom

Here’s a simple test ... turn on the system and get it to the point were it is fatiguing you ... then quickly step into the next room or hall way and listen and see if it is still as irritating

When you move into the next room over you remove yourself from the room’s direct extended ringing field and the fatigue should be reduced

If when you step into the other room it is still as irritating as the bed room ... then it is something in your system causing a tilt or frequency imbalance

Easy enough to try .. if the fatigue disappears or is reduced when you go into the next room over ... it’s your bed room ... if nothing improves when listening from the next room ... it’s something in your equipment causing the tilt

If you determine it is your room visit the ASC (Acoustic Science Corp.) site and check out what it takesto perform a inexpensive (less than $100) M.A.T.T test ... this will tell you what frequencies are ringing and how long they are ringing for

.