Harshness in tweeters: the price of transparency?

Thanks for the list of suggestions. It's no wonder I left the noise of Audioasylum for this sane place.

Now to offer some of my responses, be it dead wrong or on the money or somewhere in between.

First, more background. Let's just say I'm constrained to minimonitors at this point. Room is 12' x 20' x 8' with hobby room and entertainment room combined, splitting this 20' length into two areas.

I have 3 amplifiers I can use right now. An inexpensive 100W/ch Denon receiver, a homebrew 10W/ch 300B SET amp, and a new Red Wine Audio Signature 30.2 30W/ch class T amp. Quite a spread there.

The digital source is rarely used, but is quite void of digital artifacts and is a recent model: Ayre CX-7e.

The "linestage preamp" is an Autotransformer Volume Control. That one sounds as smooth as silk domes.

The main source is phono, which includes a Teres 255 TT with a Verus rim drive motor system. The arm is a very smooth and not state-of-the-art VPI JMW-10. The cartridge is a silky smooth Koetsu Urushi. It feeds a step-up transformer into a very good homebrew tube phono stage. That feeds the AVC linestage.

The speakers are now Focal Micro Utopia Be's and a subwoofer.

It doesn't matter what amp I use, there is always that threshold where the distortion bites my ear, except in the case of the low power SET operating out of overload where it can't be too loud to make it happen. If I do overload, it happens again in the tweeter quite easily.

I only want to reach about 103 dB at 1m from the speakers, or the full range of the 30W/ch amp. I do know the difference in the sound between clipping and tweeter ringing, or break-up.

I also found that the amp with the highest current delivery capability makes the biting ringing sound at its worst. That means the SLA battery operated Red Wine amp is the worst at being capable of ringing these tweeters. They have also been found to be usually unacceptable to most horn speaker users where the looser coupling of the SET amp makes it actually sound its best, and for both situations it seems to me.

It seems if an amp can stop the cone on a dime, the cone will want to overshoot and ring more often with these amps than the wimpy SET amps. And metal cones ring more harshly than soft cones.

I have found that an engineered network can loosen the coupling between amp and speaker and make this effect less of a problem. But it does not eliminate it.

I found it interesting to read here that stress plus SPLs equal tinnitus. I also found you can make yourself stressed internally by listening to harsh distortion and learning to ignore it, or just lose feeling of it. I know the tweeters were causing me hyperacusis back then when I could hear the tweeters produce all the irritation of the hyperacusis effect and then later the tinnitus as well. For about eight years I lived with both of these symptoms and was cured by listening 16 hours/day to white noise at the proper level for a couple of years. The ENT doctor covered by my insurance was wrong when he said there was nothing that could be done, and the audiologist specializing in "TRT" that insurance wouldn't cover could and did cure me over time.

I feel as if I'm a specialist in hearing harshness in sound, mainly highs, where it still can re-ignite my hyperacusis if too loud and distorted. Just loud isn't sufficient for me to become pained with hyperacusis again. But loud and distorted in a "harsh way" as opposed to a "soft way" will bring back those hyperacusis symptoms that lowers my threshold of pain. It can only take 90 dB of harsh sound to make it hurt, and it can take more than 110 dB if it's not harsh. This is the case for me that is.

I don't know anything about Gallo Ref 3's, but I doubt that they're minimonitors. Maybe a smaller Gallo. But what do they feature that's good? I'm curious to know more.

Kurt

More information you may need to formulate an opinion:

All Focal Utopia Be speakers operate the same tweeter at a crossover frequency of 2500 Hz and 24 dB/octave, from Micro to Grande. All Focal Utopia speakers have a minimum impedance around 3-4 ohms, with the exception of the Micro which is published at 5 ohms (maybe it really is lower). 6 ohms is nominal min impedance for a nominal 8 ohm speaker, so 5 ohms is actually close if it is actually the case. I did not see Stereophile's complete review and measurements.

The Red Wine amp is quite capable of driving 4 ohm speakers and has more current on hand for more punch with higher damping factor than about any other amp out there. It may not hold up continuously, but surely it will do so for a long note. Listening is convincing enough.

I was able to clip my amps very audibly in the midbass where most clipping happens in full range speakers and not hear it in the tweeters.

I changed the frequency of operation from "full range" to the Focal "satellites" to a 6 dB/octave rolloff starting at 70 Hz and sent 70 Hz on down to the sub. This increased dynamic range for the satellites.

Does it get to 103 dB at 1m? No, but in an ideal world it could. 30 linear watts should get me 14.77 dB above 1 watt. And 89 dB/1W/1m should get to 103.77 dB/30W/1m if uncompressed. Add a nominal 5 dB compression and there's the peak before clipping: 98.77 dB output 1m back from each speaker. What's that at the listening chair? Too much to calculate, it would need a special quasi-anechoic measurement. With that type, it should be circa 95 dB at 2m back peak output, both speakers driven. It should then be playing at a max approx 85 dB median volume level.

All that is still loud enough for me. At 10W/ch it drops to a median 80 dB max plus the lesser compression and at 100W/ch it raises to a median 90 dB max minus more compression. I know it's not the 100W/ch amp that was clipping, although not paying attention might make me believe I was doing it all the time at 30W/ch. If it clips at 30W/ch why is all the clipping happening at 6-8 KHz in some resonance fashion and nothing in the bass? It's a harsh ringing tone of dome break-up sound, not hard clipping hash or soft clipping hash.

Dropping the low frequency -3 dB cutoff to "full range", 50 Hz, compresses the woofer more, but is less at 70 Hz.

In the Diva Utopia, the midrange is exactly the same driver as the bass driver in the Micro Utopia. And when applied there, that midrange is operated 100 Hz - 2500 Hz where I operate it at 70 Hz - 2500 Hz. It would appear to me that I should have very close dynamic performance as the Diva. Is that bigger sounding? I don't know.

There's one thing I believe in most from all the info put forth and from my experiments. There are brightness difficulties associated with this tweeter at higher than average volumes that is occurring through resonance problems just like beryllium horn drivers also have. And it's not at ridiculous levels, just the higher volume end of listening. Listen to horns do that horrible harsh ringing at a live event PA address system some day and it's not killing the tweeters there either. It's driver modal breakup and resonance. And it hurts my ears every time. So I avoid those situations.

I would not try another amp change. I already did that once. I would either learn to listen always at moderate levels even if the dynamics of the recording want to go high, or look for another pair of speakers once again. And that is going to be challenging.

Perhaps DeVore, since those are favored by the owner of Red Wine Audio for his amps.

Thanks for everything. I hope this discussion is useful. I think it was for me. I don't feel my theory was destroyed, so I can act more confidently in my next decision, whenever I can afford that.

Kurt

Dcstep

What you say is true that my hearing is already damaged. The kind of damage that makes me look for that optimum clean loudness level. I have some tinnitus still in me although much better than before and is ignorable in high ambient noise. But I can't hear all that well in low ambient noise and low speaker volume conditions due to that incessant noise in my head. So I need to crank it up appropriately.

Then soon comes the other half of the problem. It distorts by playing too loud and then it starts to irritate me via hyperacusis symptoms, a lowering of my discomfort level to not as loud sound. When I had AER front loaded horns I was in a good place. Not irritating to me at loud volumes and could play well over my tinnitus level clearly. Then I went to compression horn drivers for clarity. They were clearer although not capable of high SPL's without that 6 KHz ringing hardness. The paper cone was a soft distortion and the compression horns were a hard distortion.

I probably ought to think about reverting back to those AER Oris horns again, but I hate to go backward. It will lose a lot but gain in comfort and listenable dynamic range.

Kurt

In response to the latest round of theories.

I have tinnitus in both ears equally (from a well balanced stereo, of course) at a perceived frequency centered around about 7 KHz. This is a common frequency to get tinnitus. Why? It's actually very explainable. The hairs inside the cochlea of the ear hear sound starting at the highest frequecies nearest the point of entry where the stapes bone is connected. The cochlea winds like a Nautilus and as it goes inward the frequencies we perceive on the hair cells go down in frequency. This reaches a limit where the really low frequencies are perceived by the semicircular canals that also help in balance. Now you know why very high SPLs at infrasonic frequencies can make you feel a little ill.

So again, why 6-8 KHz is typical tinnitus frequency of perception? Same reason it is also the most common area of hearing loss: the position of the hair cells where we hear that range of frequencies sits right on the first bend in the cochlea. The sound waves hit this area the hardest by mechanical means. Somewhere in this range also lies our most sensitive hearing range as well, because it receives the most signal, and is well known as in the presence region.

Also, this tinnitus region is also my worst hyperacusis region. My hearing damage has shown no hearing loss as everyone would expect, but has tinnitus and hyperacusis exactly where we would also expect that loss. Why? Because theoretically the damage was not long enough and loud enough to flatten dead the hairs in the cochlea there but was short enough and sharp enough to damage perhaps the function of those hair cells and down the nervous system from there. Hyperacusis is an excessive perception of volume that we think is caused by nerve damage where the nerves aren't good enough to feedback quickly enough the automatic gain control in our hearing system. Tinnitus is also a nervous system disorder in the hearing system where likely the nerve firings don't want to stop. It's very common to have both symptoms.

When I got rid of my first metal dome tweeter speaker, I found I could listen to soft domes. The next speaker choice was a ProAc Response 3. The next was implementing what I learned about frequency range of damage and designed and built my own speaker. It was a little cross between the ProAc Response 3 and the Avalon Ascent, as much as I could imagine the implementation to be correct and use off-the-shelf drivers and crossovers.

The drivers were a Scanspeak D2907 fabric dome tweeter from 6 KHz on up, 24 dB/octave acoustically Linkwitz-Reilly, similar to ProAc's tweeter with less frequency coverage for smoother performance from this otherwise slightly rough tweeter. The other crossovers were all the same type of filter. The midranges were two MB Quart 2" titanium domes, the driver that was modified and used in the Ascent. They operated from 700 Hz - 6 KHz. The woofer was an Eton 8" Nomex-Kevlar design that is still around and popular to this day.

The result with a pair of titanium domes in there? No problem with hardness whatsoever. The peaking that occurred in-band in the tweeter region was filtered way down. The hardness was not perceived because A) it was not stressed by overcoverage of low frequencies and B) it was not overstressed by the fact I used two of them for more output from less excursion from each. The 8" Eton had no problem reaching 700 Hz.

That speaker sounded pretty good I thought. My friend heard them too and wanted to buy them. When I decided to go flea power SET and horns I did sell them to him and bought the smoothest horn I have heard - the Avantgarde DUOs. Those do not shout and play plenty loud without any harshness. I thought this was perfect, until the day I heard the Oris 150 horn. It will shout at very high SPLs but it wasn't terribly harsh either. It was simply more articulate and detailed and got rid of that plastic-like sound that was always there in the DUOs.

Then I heard about everyone abandoning Oris horns for Orphean horns because of a leap in articulation and detail and dynamics, and at 112 dB/1W/1m from 250 Hz on up it took only a 1/4 watt amp to play loud. But it had a fatal flaw for me. There was a resonant peak at 6.5 KHz and it was harsh when excited in that region. Nothing I could do could change that, it was inherent to the coaxial compression driver in the mid driver, but not the tweeter driver. Funny thing was, the 2" throat it used has a major acoustic modal point at exactly 6.5 KHz. And the crossover between midrange and tweeter compression drivers inside was also at 6 KHz. I tried changing the crossover but some acoustic crosstalk between the drivers kept that 6.5 KHz peak going. Yikes! Finally I gave up, sold them, gave up on horns altogether and since I heard many metal domes that controlled harshness, I figured the well reviewed Focal Utopia speakers couldn't mess it up.

Maybe I still have the wrong amp, but I can't imagine that a super low output impedance amp is really going to fix everything. Quite the opposite seems true to me - the high impedance amp reduces harshness, or even adding series resistance to the speaker reduces harshness.

As to my source, my Sennheiser HD-595 headphones don't perceive anything wrong even at the very loudest settings where I have to move them off my ears.

The only thing I need to check out further is if the 30W/ch amp is actually clipping every time I hear a resonant assault on my ears. It might be, and then I need to surely back off on the volume controls like I'm doing already out of necessity.

I did go to see Indiana Jones this weekend and it was a very clean horn system without harsh digital artifacts either. It was louder than I ever play my system these days and I walked out with no pain. I want those speakers I think. But those are way too big.

Kurt