Harshness in tweeters: the price of transparency?
Kurt, it sounds to me like you are running into more than one issue. I could be wrong, but at home I can run the system up to 110 db without any added harshness. In fact the system comes off sounding the same at that volume as it does at 85db- there are no loudness cues. My speakers are 97 db, very easy to drive, and have hard metal diaphragms. I've put a lot of effort into creating 'stillness' in the front end so that it is unperturbed by high volume levels: the preamp and turntable both reside on anti-vibration platforms, which in turn are decoupled from a custom-built Sound Anchors stand, which rests upon Aurios Pro bearings. The amps sit on Silent Running Audio stands. In addition, the equipment I'm running is designed with intention to not create loudness cues and artifacts. The amps you are using are built with other goals. IMO if you want a relaxed sound at high volumes, you will have to work with equipment that is designed for that purpose... |
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 |
From Stereophile: The Focal-JMlab Diva Utopia Be's ported enclosure was tuned to approximately 27Hz, with minimum impedance of 3.38 ohms at 100Hz. I would judge this speaker to be of average difficulty to drive for any amplifier comfortable with a 4 ohm load, and I would rate its nominal impedance at 4 ohms. The speaker's sensitivity measured approximately 87dB/2.83V/m.Maybe this isn't your speaker? The Redwine may be able to drive 4 ohms, many amps are, but that does not mean it doubles power into 4 ohms compared to its power into 8 ohms, and since Redwine does not publish the 4 ohm spec for the 30.2 there's no way to verify it. I recall Vinnie stating on another website that it did not. The Street dot com says this in their review: The amp is capable of delivering 30 watts per channel into any speaker load from 4 to 16 ohms.That's essentially what tube amps do...deliver the same power into various impedance loads, and it's why many tube amps don't sound right on speakers with wide impedance swings. 30 watts into 4 ohms produces fewer decibels than 30 watts into 8 ohms, thus perceived pronounced upper frequencies. You have Voltage Paradigm speakers, and two Power Paradigm amplifiers. A mismatch. Ralph Karsten has a white paper on this topic here. This is a moot point since you state you will not change amps. So, perhaps a change to Power Paradigm speakers (like Devore, Coincident, Merlin, Audiokinesis...) will help get you closer to where you want to be. Anyway, good luck. |
Ktstrain- If you want to play horns and cymbals loud and clear, you need to follow Dcstep's example. First, learn how to play trumpet. Second, wait 40+ years to get a system that sounds good. Next, get some small rear ported floor standing speakers with a laid-back tonal balance and woofers that are connected with inverted polarity, see: http://stereophile.com/floorloudspeakers/506vienna/index4.html Position these speakers very close to the wall behind them, place a gigantic armoire in the center of the speakers, and put a small reflective table directly in front of the left speaker. See: http://forum.audiogon.com/cgi-bin/fr.pl?vdone&1198908516 Finally, claim you've reduced Intermodulation Distorion using the "Sumiko's Master Set," without ever taking any measurements to confirm your claims. Did I miss anything Dave? |
