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In Reply to: RE: Boring in closing reply!! posted by tomservo on March 04, 2025 at 16:37:55
Right Tom we recognize these short but high peaks. Can they do damage and at what duration? Can we and should we try to reproduce them? We don't have the data to know and it would be difficult to obtain it. Maybe we should volunteer dogs and bats to study?
Follow Ups:
I'd refer you to two sources: The Acoustical Society of America, and the American Journal of Otology. Both are likely to have multiple papers on the topic, both legacy and recent. They're neither free nor cheap, but they are excellent sources if you're looking for the science.
Have at it!
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We are inclusive and diverse, but dissent will not be tolerated.
"Maybe we should volunteer dogs and bats to study?"
I guess you could, others might look at what has already been discovered about this. An eye opener to start might be an early work called "Infrasound and low frequency vibration edited by Tempest.
I would point out that while a gunshot can be 165dB or more, no one is proposing reproducing that at actual level.
A minor problem is difficulty if that was desired, lets say you had an 85dB 1w/1m loudspeaker and you were willing to sit a meter away. Assuming the speaker was linear and all the parts stayed attached and intact, you need 80dB over 1w to get 165dB That's 100,000,000 Watts.
Remember this is a log scale going up 10dB from any level takes 10 times the power, 20dB is 100X..
Do you think the reason loudspeaker / amplifier combo's generally don't address all of the existing dynamics is because they are not audible when added back -or- the danger in reproducing every day levels faithfully, or is it because it's difficult because of the numbers involved and it's inaudible as a "flaw" until compared to with?
To your point:
Does it means that listening to RECORDED music, even with full, modern dynamics, from 2 microphones at live unamplified EVENTS, as direct to a 130 db range digital medium as possible in the shortest recording/playback chain to efficient speakers, still have a built in LIMITER then?
The physics of membrane surface area sensitivity/response amplitude/bandwidth vs. the mass and thermal compressions of the speakers act as such "acoustic filters and limiters," do they not?
Assuming unmodified, linear signal integrity in the chain of electronics and amplifier, of course, yes?
"Does it means that listening to RECORDED music, even with full, modern dynamics, from 2 microphones at live unamplified EVENTS, as direct to a 130 db range digital medium as possible in the shortest recording/playback chain to efficient speakers, still have a built in LIMITER then?"Yes. There are at least two "built-in" limiters. As mechanical transducers, both microphones and loudspeakers have an inherent limitation: rise time.
Even the best measurement microphones (e.g., B&K) have this limitation, although it is very slight - that's one reason why they're so expensive. I couldn't afford that kind of extreme setup, so I bought the "best" recording microphones available at the time - Schoeps dual-pattern condensers - and even they choke on a couple of instantaneous peaks such as a gunshot or fireworks "aerial salute".
At the other end of the chain, there's the loudspeakers. Again, as mechanical components, they take time to start moving. This effectively makes them a limiter, and is one reason why light diaphragms in a strong magnetic field, well-coupled to the outside world, are generally better at reproducing high crest factor signals. Compression drivers and other horn-loaded drivers and electrostatics come to mind.
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We are inclusive and diverse, but dissent will not be tolerated.
Edits: 03/08/25
Hi Claude
This is a hard question to answer as it is like Ivan often said "it depends"
I think you met him when you were at the shop, Ivan was on the AES committee trying to set a standard for measuring with a signal more like music.
That test is AES-75 (i think) or M-noise that tests the maximum level the loudspeaker can accurately produce a music like signal.
It does this by having a music spectrum noise signal with a 10dB peak to avg which reveals max level at minimum compression AND a +17dB peak every so often that has to be preserved to pass as well.
We test some of our smaller cabinets this way but this means having amplifiers that can put out the +17dB over average RMS level which isn't practical once getting to the large cabinets and it meant getting a VERY expensive microphone that went past 155..
In your case, you could assume the 50's are not the limit in a living room, they were usually in a large rooms or Church's etc so you could figure backwards to a theoretical ceiling. I have a fondness for that one, it was the first box i designed when we started the company 20 odd years ago and we still sell them, i still have the first two in my living room.
Say you were 2 meters away from one operating so -6dB from 1m. sensitivity around 100dB 1w and say you had 200W amp, that's 23dB over 1W so a peak level of 117dB is possible with a peak of 200W. If you were playing a recording with a 20dB peak to average, then the max average level is 97dB at onset of V clipping. At 4 meters away, it'-6 again so 91dB.
So if you had 200W per, that ought to be plenty loud and you have subwoofers that can keep up. Ought to be possible to play movies effectively considering you have half of the subwoofers used in an omni max / I max theater haha.
Now, compressed FM radio is more like 10dB peak to avg so it can go a lot louder before reaching the peak limit.
A fir reply in the works
Tom
Hi Tom,
Incidentally, +17 db was the "headroom" number Paul Klipsch told me to use when you and I were still "kids" with no gray hair!
I talked to Ivan years ago before I met him in person (twice total at shop).
In my past life I was a world class Printed Circuit board designer and I complimented him on the one he did for the SH-50, since I had a chance to get a naked pair to add to 2 SH-50's that were used without passives prior, and sold to a Canadian friend. That crossover is a true work of ART!
Also, when I first talked to Ivan on phone (not yet in person circa 2014?) I was ordering my pair sound unheard in White and he talked me out of SH-60's in favor of the SH-50's, so you have him to thank for that, or not. LOL. He thought the 50 was the better performer, but close.
The noise signal to which Tomservo is referring was developed by Meyer Sound Labs in Berkeley, CA. (meyersound.com). "M-noise" (music-noise) is an attempt to improve upon various other continous noise types as a means of measuring loudspeaker performance, by more closely approximating music waveform characteristics. And, yes, it is now AES standard AES75-2023. I've provided some links below. (Because there are more than one, and I'm lazy, you'll have to actually highlight and then right-click to open them.)Aside: Way back in the mid-1970s, I was fortunate to have John Meyer as one of my mentors, when he was doing R&D at l'Institut des Hautes Etudes Musicales (Institute for Advanced Musical Studies) in Montreux. This was when he had already been doing loudspeaker design for McCune Sound, and later for A&M Records studios. (He started Meyer Sound Labs in 1979.)
Anyway... One of the fundamental things he taught me was the importance of high crest factor peaks - that very high quality sound reinforcement/playback can be more detrimental to our hearing than "compressed" or lower quality/high distortion sound, because our ears and brains are primarily reacting to the "average" sound level and perceived distortion, rather than the peaks. With less distortion, we tolerate higher average levels, and that creates a hearing issue with high level peaks.
https://meyersound.com
https://meyersound.com/news/m-noise-test-signal/
https://m-noise.org/
https://www.aes.org/standards/AES75/
*********
We are inclusive and diverse, but dissent will not be tolerated.
Edits: 03/08/25
Got blue PAINT for my black Klipsch K-402 horns on top of my Tigerwood Jublee Clones? The twin 12" drivers had the Sd of an 18, and with only +5 db of EQ at 30 Hz, they made the flesh in my calves move.I heard Meyer sound speakers at the Ka'/MGM Cirque Du Solei in Vegas, 2009.
Great show with really good sound from lots and lots of speakers with directional cues in the system that, likely, cost a fortune, which MGM could easily afford.While I applaud their efforts at better test signals, I'm not impressed with their latest "blue sound" speakers. I'm sure they sound OK and all that. Man, I guess they want to amortize their R&D and tooling with a single sale!
At a jaw dropping unfrikkinbelievable price of $65,500 plus shipping (for God's sake!) it's edging on the direct proportion of a name and ripoff category.
This last Millenium box and horn technology is really nothing special, other that refinement of the integration of Electronics. Especially since they don't horn load the conventional drivers using what look like jbl, EV, or even Klipsch Pro black boxes. Even Klipsch's Roy Delgado now makes a Horn Loaded Theater Sub with an 18" and ports if you are going to add a separate bottom.
I can do much better with a mold and my friend's CNC unit for the cabs and horn with blue plastic or paint (oooooh now that's "impressive"..........not). And if a sub box is allowed, then my Super TH sub (Tom Danley inspired).
Aside from that Using Hypex or Purifi's incredible class D offerings coupled with DEQX FIR speaker controls would still let me kick that sound to the Meyer blues to the curb while having enough cash leftover to take my family to a 2 week Vacation in Hawaii!!
Edits: 03/08/25 03/08/25
Any of Danley Sound Labs Jericho or even the "miniature" Synergy horns with a separate bottom end to get down to 20, with DSP would be a much better choice if you line up the Price to Performance ratio in the process.
Heck for only 8 cubic feet of floor space and way better, single box integration this would be my choice, and I'd still have Hawaii Vacation money leftover for a Home or Sound Studio application!
https://www.sweetwater.com/store/detail/HRE--tom-danley-signature-series-hre1-4400-watt-4-way-powered-loudspeaker
Tom in regards to your last paragraph it's all the above!! Also recording an Instantenous Event accurately is challenging to the recording chain. Mics, preamps, AD-DA etc. Add the high SPL and it's even more difficult.
Can improvement occur?? What would be the new frontier for me? Gallium nitrade chips, New driver designs: multiple magnetic gap speakers, intelligent voice coils, new design suspensions for longer linear Xmax. Convertible hi Efficiency horn speakers that can be folded to small size for live sound.
Tom already makes Miniature Loudspeakers, for their a given power output of any size.
Most people have no clue about this. FACT
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