Griesinger's teachings show up in Klippel, Linkwitz, Toole, and Geddes

[DaveC]

IMO, this is the underlying explanation for our acclimatisation (we can accept most systems as long as there are no major issues) & it also explains how we can become fatigued over time listening to our playback system - it doesn't engage our attention, involve us emotionally (see above) - just replays all the note sin the correct order (I think

With fatigue, I think it's even worse... the system is producing sounds that trigger an alert response. Some sounds stimulate the nervous system's alert response simply due to genetics, like the fact we're very sensitive to smells of decay to keep us from eating things that make us sick. In the same way we key into certain sounds to keep us from being eaten by predators.

I also think there's levels of overall nervous system stimulation and the preference for warmth is mostly driven by the preference for a system that is less stimulating. OTOH, others may prefer a more stimulating system, and there are electronics and cables that enhance leading edges and attack, add sounds that stimulate alert response, and some find this exciting.

 

[microstrip]

(...) Here is my in-a-nutshell philosophy of what a speaker should do; it contains elements of what you are saying but is not as well articulated:

There are two things a speaker should do. First, a speaker should do SOMETHING so well that the listener can, when focusing on that something, suspend disbelief and get lost in the music. That something can be timbre, clarity, imaging, impact, inner detail, immersion, PRAT, whatever. If a speaker can do more than one of these things, so much the better. But this is the easy part.

The HARD part is, a speaker should ALSO be free of colorations and inadequacies which collapse that hard-won illusion.

Very interesting. Why do you consider that doing things well is an easy part and dealing with the inadequacies is the hard part? Which technical aspects do you relate intrinsically with each of them?

 

[Duke LeJeune]

Very interesting. Why do you consider that doing things well is an easy part and dealing with the inadequacies is the hard part?

Just my opinion, but it seems to me there are lots of speakers which do something well, but relatively few that don't also do something poorly.

 

[Duke LeJeune]

Which technical aspects do you relate intrinsically with each of them?

Hmm, that's a pretty big question. Let me start with the first thing I mentioned and see how far I get.

So, which technical aspects do I relate intrinsically with timbre?

In pursuit of natural-sounding timbre, I shoot for a smooth and gently downward-sloping frequency response curve for the first arrival sound, and I try to get the reverberant sound as similar in spectral balance as I reasonably can. I like the timbral richness that comes from a well-energized reverberant field, but try to avoid having a lot of early reflections because ime they degrade clarity which makes it harder to hear the "textural" aspect of timbre. To convey texture properly imo resonances must be kept to a minimum, in the drivers as well as in the cabinet. And we need to avoid acoustic problems like diffraction, which can impart a harshness particularly at higher SPLs, which can instantly ruin the timbre. I pay particular attention to certain frequency regions where either the ear is most sensitive, or where mechanical resonances seem most likely to occur.

I'm not sure that paragraph conveys anything useful. In reading it over just now, it sounds like a first draft of poorly-written ad copy... like trying to mention too many sound-bite topics and doing none of them justice.

I may come back to your question another time, after I've mulled it over a bit, but a complete answer is probably beyond the scope of what I can do.

If it's obvious to you that I've misunderstood your question, could you re-phrase it, and I'll try again?

 

[KlausR.]

Hello Duke,

have been abroad for a while with no internet connection.

Happy New Year to all.

The argument is that you don’t perceive the last/late part of reverberation anyway because it is masked by the music being played continuously. You only would hear reverberation fading into inaudibility when the sound/music is stopped suddenly. From Blesser 2001: “In continuous music, only the first 10 dB of decay can be perceived because the remaining reverberation is masked by the next part of the music. This is called “running reverberance.” The reverberation tail, “stopped reverberance”, is perceived only when the music stops.”

What I'm doing is adding reverberant energy which starts out about 10 dB down relative to the direct sound. If Blesser's findings apply, any effects would be imperceptible until the music stops. And if such is indeed the case, then clearly I have been deluding myself all along.

Your effect is based on a first ceiling reflection, with the other first reflections being weakened by narrow dispersion speakers, Blesser is talking about reverberation. Two different issues.

Would you have any interest in the other kind of listening? It may be possible to configure a crude but adequate test system. If this might interest you, let me know whether you have access to a pair of small speakers which can be played at the same time as your big Klein & Hummels, and we can take a look at the feasibility.

If that test is what I think it is, feasibility would be an issue: in our living room we have an acoustic ceiling in the form of a stretched fabric with the air space above filled with rock wool, so basically there are no ceiling reflections. To make that test I would have to clear the dining area of our kitchen-diner from all furniture and move the system, which would include pulling the preamp with all cables, which are in cable compartments of the custom-made piece of our audio/TV furniture (see pic). At this point WAF would come into play.

... I can’t but repeat myself: white paper.

How would that change the legitimacy (or lack thereof) of my opinions?

There is, of course, absolutely no need to justify or legitimize your, or anybody else’s, opinion, this goes without saying. I only thought that a white paper would make things clearer for people visiting your website.


Klaus

 

[Duke LeJeune]

I'm not a researcher in the field so don't have a wide range or depth of readings in the field. My interest stems from my experiences in audio & attempts to understand & explain what I'm perceiving. I consider I'm on a journey in trying to understand a very complex, unfinished & active field of auditory perception research...

Apologies in advance for the tangent/slash/potential thread de-rail:

Jkeny, in your explorations of the published research have you come across anything related to the tactile perception of sound... what we might call "impact"?

If so, by any chance, anything that might pertain to the time window within the nervous system (limbic system, sympathetic nervous system?) intergrates tactile sensations into "impact"? It might be related to the firing rate of sensory neurons in the skin, which I think maxes out at about 400 Hz. But then there is also the time required for nerve impulses to reach the central nervous system possibly from different areas of the body, though "chest-thump" - presumably from sensory receptors in the torso - may be the most relevant.

Anyway my reason for asking is, I'm trying to figure out if there is a critical-to-tactile-perception first-arrival-time window for multiple subwoofers. Or to put it another way, what I hope to eventually get a handle on is whether there is a perceptual tradeoff in tactile sensation for the superior in-room response smoothness of a distributed multi-sub system, and if so, what is the arrival-time "window" outside of which the sensation of impact is degraded?

Not that I expect you to know this off the top of your head, and I certainly do not expect you to look anything up, but if you recall anything that might point me in the right direction, I'd appreciate it very much.

 

[jkeny]

Hi Duke
It's not an area I have paid much attention to - I struggle enough trying to research/understand one mode of perception never mind multi-modal perception.
But I did a quick search & this might be a good starting point for your research "Auditory-Tactile Experience of Music"
This is a recent article & I often find them a good source of references to other relevant & probably seminal material
Hope you find it of use?

PS This also seems useful https://www.dhi.ac.uk/openbook/chapter/ICMEM2015-Merchel

But all the research I've seen seem to use electromechanical body exciters rather than woofers

 

[DaveC]

Part of the reason I prefer a large front-firing woofer w front-firing BR port is that I believe it recreates drums better, especially kick drums in a set. I think having air accelerated at the LP by the woofer and ports is noticeable, especially with designs like Pass' SLOB woofer arrangement or front horn.

I believe a sub setup can provide impact, the issue is the main woofer is often smaller in systems with sub setups. I think it's still better to have as much woofer surface area as possible, even if the woofers don't have to reach under ~40-50 Hz. Similarly, I think more midrange driver area is better, or a horn. Impact is a phenomenon that covers the entire frequency range, for example kick drums are really a full-range instrument and you'll hear that HF information just before the lower frequencies, so really, the bigger the speaker the better, at least imo... And horns are effectively big speakers due to impedance matching with the air improving efficiency, and the reason they can have excellent dynamics and impact.

 

[Duke LeJeune]

I did a quick search & this might be a good starting point for your research "Auditory-Tactile Experience of Music"
This is a recent article & I often find them a good source of references to other relevant & probably seminal material
Hope you find it of use?

PS This also seems useful https://www.dhi.ac.uk/openbook/chapter/ICMEM2015-Merchel

But all the research I've seen seem to use electromechanical body exciters rather than woofers

Thank you very much!

I read the papers/articles at those links as well as one of the papers cited which seemed likely to be relevant, and didn't find anything that addressed precisely what I'm curious about... BUT it looks like "perceived simultaneity" of auditory and tactile stimulus occurred when the tactile stimulus was in effect "first", by a time interval (7 milliseconds in the case of tactile stimulus at the hands) which synchronized the arrival of the audio and tactile signals at the brain. I think this implies a fairly tight time window for first-arrival bass pressure from multiple sources. I'll keep looking.

Part of the reason I prefer a large front-firing woofer w front-firing BR port is that I believe it recreates drums better, especially kick drums in a set. I think having air accelerated at the LP by the woofer and ports is noticeable, especially with designs like Pass' SLOB woofer arrangement or front horn.

My understanding is that the output from the port lags the output from the front of the cone by 180 degrees, and I've heard ported systems with imo excellent "slam", so perhaps the time window for integration of multiple arrival times in the bass region is at least 1/2 wavelength wide?

You mentioned the Slot-Loaded Open Baffle... I assume you've found it to do good job with impact? In my experience that's been a weakness of dipole systems. I would expect the slot loading's benefits to be confined to the nearfield, but I haven't really looked into it.

I believe a sub setup can provide impact, the issue is the main woofer is often smaller in systems with sub setups. I think it's still better to have as much woofer surface area as possible, even if the woofers don't have to reach under ~40-50 Hz. Similarly, I think more midrange driver area is better, or a horn. Impact is a phenomenon that covers the entire frequency range, for example kick drums are really a full-range instrument and you'll hear that HF information just before the lower frequencies, so really, the bigger the speaker the better, at least imo... And horns are effectively big speakers due to impedance matching with the air improving efficiency, and the reason they can have excellent dynamics and impact.

Agreed!

Most of my work is with bass guitar speaker cabinets, and my observation is that not only does effective cone area matter, so does motor strength. But so does the in-room frequency response: In my experience if the response curve doesn't support "thump" as opposed to "boom" or "meh", neither cone area nor motor strength can make up the difference... therefore, I build an unusual amount of tuning flexibility into my bass cabs via multiple pluggable ports. Imo in the bass region there are a lot of things to get right... or to put it another way, there are a lot of opportunities to get it wrong!

 

[sbo6]

Part of the reason I prefer a large front-firing woofer w front-firing BR port is that I believe it recreates drums better, especially kick drums in a set. I think having air accelerated at the LP by the woofer and ports is noticeable, especially with designs like Pass' SLOB woofer arrangement or front horn.

I believe a sub setup can provide impact, the issue is the main woofer is often smaller in systems with sub setups. I think it's still better to have as much woofer surface area as possible, even if the woofers don't have to reach under ~40-50 Hz. Similarly, I think more midrange driver area is better, or a horn. Impact is a phenomenon that covers the entire frequency range, for example kick drums are really a full-range instrument and you'll hear that HF information just before the lower frequencies, so really, the bigger the speaker the better, at least imo... And horns are effectively big speakers due to impedance matching with the air improving efficiency, and the reason they can have excellent dynamics and impact.

Part of the reason I prefer a large front-firing woofer w front-firing BR port is that I believe it recreates drums better, especially kick drums in a set. I think having air accelerated at the LP by the woofer and ports is noticeable, especially with designs like Pass' SLOB woofer arrangement or front horn.

I believe a sub setup can provide impact, the issue is the main woofer is often smaller in systems with sub setups. I think it's still better to have as much woofer surface area as possible, even if the woofers don't have to reach under ~40-50 Hz. Similarly, I think more midrange driver area is better, or a horn. Impact is a phenomenon that covers the entire frequency range, for example kick drums are really a full-range instrument and you'll hear that HF information just before the lower frequencies, so really, the bigger the speaker the better, at least imo... And horns are effectively big speakers due to impedance matching with the air improving efficiency, and the reason they can have excellent dynamics and impact.

IME it's not that simple. Sub and mid driver size is only part of the equation with driver excursion and distortion of higher importance. Also, more drivers which commonly = lower distortion (and aligns to your more surface area is better stance) is often times more beneficial. I also believe that the best scenario includes more drivers each covering less frequency range = effortless, dynamics and heft (like your kick drum example). For example, with my Vivid Audio Giya G2 S2s the advantage of a 4 way = each driver is responsible for only 2 octaves except the woofers which in my case I plan to roll off @ 2 octaves and have my JLA quad manage <=60Hz = less effort, better dynamics and a more realistic kick drum, as you say.

 

[DaveC]

IME it's not that simple. Sub and mid driver size is only part of the equation with driver excursion and distortion of higher importance. Also, more drivers which commonly = lower distortion (and aligns to your more surface area is better stance) is often times more beneficial. I also believe that the best scenario includes more drivers each covering less frequency range = effortless, dynamics and heft (like your kick drum example). For example, with my Vivid Audio Giya G2 S2s the advantage of a 4 way = each driver is responsible for only 2 octaves except the woofers which in my case I plan to roll off @ 2 octaves and have my JLA quad manage <=60Hz = less effort, better dynamics and a more realistic kick drum, as you say.

Sure... surface area, excursion and distortion all go hand-in-hand. More surface area generally means less excursion and distortion.

More ways and steeper slopes reduces IMD, intermodulation distortion, and is better for complex music as well.

 

[Duke LeJeune]

Sub and mid driver size is only part of the equation with driver excursion and distortion of higher importance. Also, more drivers which commonly = lower distortion (and aligns to your more surface area is better stance) is often times more beneficial.

My personal gravitation towards large surface area midwoofers is to take advantage of their beaming to get the radiation pattern narrow enough to match that of the horn in the crossover region. So it's not the surface area per se that is my primary motivation, rather it is the resulting narrowed radiation pattern. Any reduction in distortion is a welcome side effect, but then big cones go into breakup earlier, which has to be well controlled. So it's a juggling of tradeoffs.

I also believe that the best scenario includes more drivers each covering less frequency range = effortless, dynamics and heft (like your kick drum example). For example, with my Vivid Audio Giya G2 S2s the advantage of a 4 way = each driver is responsible for only 2 octaves except the woofers...

That makes sense to me. Of course there are tradeoffs associated with crossovers as well, with the devils being in the details.

The Vivids are about as close to a "no compromise" embodiment of their designer's philosophy as I think we're ever likely to see. Laurence Dickie did everything I can think of to take his philosophy as far as it can possibly go, and did some things that I never would have thought of... like his catenoid dome profile which pushes breakup far higher in frequency than a normal aluminum dome could ever go. My overall philosophy is obviously very different, but I cannot (yet) claim to have been as thorough in its pursuit as Laurence has been in the pursuit of his.

 

[sbo6]

My personal gravitation towards large surface area midwoofers is to take advantage of their beaming to get the radiation pattern narrow enough to match that of the horn in the crossover region. So it's not the surface area per se that is my primary motivation, rather it is the resulting narrowed radiation pattern. Any reduction in distortion is a welcome side effect, but then big cones go into breakup earlier, which has to be well controlled. So it's a juggling of tradeoffs.

Can you please elaborate? I would think that the larger the driver's surface area would = less beaming assuming the same frequency across comparative drivers.

 

[Duke LeJeune]

Can you please elaborate? I would think that the larger the driver's surface area would = less beaming assuming the same frequency across comparative drivers.

The idea that a larger driver has a smaller (narrower), rather than larger (wider) radiation pattern is certainly counter-intuitive. But let me try to explain:

Imagine you are 45 degrees off-axis of a woofer which has a nominal diameter of 6 inches and an actual cone diameter of 5 inches. The nearest edge of the cone is about 1.75 inches closer to your ears than the middle of the cone. That 1.75-inch difference is insignificant at say 100 Hz, where it is equal to about 1/77th of a wavelength.

But up at 3.8 kHz, that 1.75-inch path length difference is equal to one-half wavelength. So at 3.8 kHz, the output from the middle of the cone arrives 1/2 wavelength behind the output from the nearest edge of the cone, which corresponds with being 180 degrees out-of-phase, and therefore the two cancel each other out.

Now in practice there are many points on the cone and therefore many different off-axis path lengths, so the net result is only partial cancellation. The general trend is, as the off-axis angle increases, the net amount of cancellation also increases. This is where beaming comes from.

And the larger the cone diameter, the lower the frequency at which these off-axis path-length-difference cancellations start to occur.

Imagine now a woofer with a nominal diameter of 15 inches and an actual cone diameter of 13 inches. At 45 degrees off-axis, the path length difference between the nearest edge of the cone and the middle of the cone is about 4.5 inches, which in turn corresponds with one-half wavelength at 1.5 kHz. So we see that a 13 inch cone's pattern-narrowing at 1.5 kHz is comparable with a 5-inch cone's pattern-narrowing up at 3.8 kHz. (Once again, there are many points on the cone so the net cancellation is only partial, and the general trend is for the pattern to become narrower as we go up in frequency).

As a ballpark rule of thumb, when the cone diameter is equal to one wavelength, the radiation pattern has narrowed to 90 degrees - that is, the off-axis energy is -6 dB at 45 degrees to either side of the centerline. So... if "beaming" is considered to occur when the radiation pattern has narrowed to 90 degrees, we might say that beaming sets in at 2.7 kHz for the 5-inch cone ("6-inch" woofer), and at 1.0 kHz for the 13-inch cone ("15-inch" woofer).

If we're talking about 1" dome tweeters the path length differences are of course much less, but still beaming does start to set in north of about 13.5 kHz. That's where the dome diameter is equal to one wavelength, and so it is where the radiation pattern has usually narrowed to about 90 degrees (-6 dB at 45 degrees off-axis to either side).

I hope this helps. Let me know if I need to try again.

 

[sbo6]

The idea that a larger driver has a smaller (narrower), rather than larger (wider) radiation pattern is certainly counter-intuitive. But let me try to explain:

Imagine you are 45 degrees off-axis of a woofer which has a nominal diameter of 6 inches and an actual cone diameter of 5 inches. The nearest edge of the cone is about 1.75 inches closer to your ears than the middle of the cone. That 1.75-inch difference is insignificant at say 100 Hz, where it is equal to about 1/77th of a wavelength.

But up at 3.8 kHz, that 1.75-inch path length difference is equal to one-half wavelength. So at 3.8 kHz, the output from the middle of the cone arrives 1/2 wavelength behind the output from the nearest edge of the cone, which corresponds with being 180 degrees out-of-phase, and therefore the two cancel each other out.

Now in practice there are many points on the cone and therefore many different off-axis path lengths, so the net result is only partial cancellation. The general trend is, as the off-axis angle increases, the net amount of cancellation also increases. This is where beaming comes from.

And the larger the cone diameter, the lower the frequency at which these off-axis path-length-difference cancellations start to occur.

Imagine now a woofer with a nominal diameter of 15 inches and an actual cone diameter of 13 inches. At 45 degrees off-axis, the path length difference between the nearest edge of the cone and the middle of the cone is about 4.5 inches, which in turn corresponds with one-half wavelength at 1.5 kHz. So we see that a 13 inch cone's pattern-narrowing at 1.5 kHz is comparable with a 5-inch cone's pattern-narrowing up at 3.8 kHz. (Once again, there are many points on the cone so the net cancellation is only partial, and the general trend is for the pattern to become narrower as we go up in frequency).

As a ballpark rule of thumb, when the cone diameter is equal to one wavelength, the radiation pattern has narrowed to 90 degrees - that is, the off-axis energy is -6 dB at 45 degrees to either side of the centerline. So... if "beaming" is considered to occur when the radiation pattern has narrowed to 90 degrees, we might say that beaming sets in at 2.7 kHz for the 5-inch cone ("6-inch" woofer), and at 1.0 kHz for the 13-inch cone ("15-inch" woofer).

If we're talking about 1" dome tweeters the path length differences are of course much less, but still beaming does start to set in north of about 13.5 kHz. That's where the dome diameter is equal to one wavelength, and so it is where the radiation pattern has usually narrowed to about 90 degrees (-6 dB at 45 degrees off-axis to either side).

I hope this helps. Let me know if I need to try again.

Thanks for the detailed explanation, it makes perfect sense. The only additional question I have is - in both of your examples both drivers would in most applications be crossed over at lower frequencies versus the cone edge to middle cone delta 1/2 wavelength (15" woofer at 1.5KHz and 6" mid/woofer at 3.8KHz). As such I would assume that for most practical applications beaming is less of an issue?

 

[Duke LeJeune]

Thanks for the detailed explanation, it makes perfect sense. The only additional question I have is - in both of your examples both drivers would in most applications be crossed over at lower frequencies versus the cone edge to middle cone delta 1/2 wavelength (15" woofer at 1.5KHz and 6" mid/woofer at 3.8KHz). As such I would assume that for most practical applications beaming is less of an issue?

I just picked the distance delta between middle of cone and edge of cone as an arbitrary example; the resulting frequency of cancellation has no particular significance. I probably could have done a better job of coming up with a representative example.

The frequency that is of more general interest is where the cone diameter equals one wavelength, which is where the pattern has narrowed to about 90 degrees. So, 1.1 kHz for the 15" woofer and 2.7 kHz for the 6" midwoofer.

In my opinion where beaming (or lack thereof) is most likely to cause a problem is just north of the crossover between that 6" midwoofer and the 1" dome tweeter that it is probably paired with. We transition from the midwoofer's roughly 90 degree pattern to the 1-inch dome's 180 degree pattern... the latter would probably be even wider, except that the front baffle acts as a 180 degree "horn" and keeps the tweeter's pattern approximately hemispherical at the bottom end of its range.

So what we end up with is, a LOT of off-axis energy at the bottom end of the tweeter's range, say between 2.5 and 5 kHz. Well it just so happens that the 3-4 kHz region is where the ear is most sensitive. And even if the on-axis response is flat, by the time we factor in the off-axis energy's contribution, we have a net excess of energy in that sensitive 3-4 kHz region. The net result can be an overly bright or sometimes even harsh or edgy sound, and/or listening fatigue over time.

The approach I generally use involves a fairly big midwoofer (ten to twelve inches nominal diameter) crossed over to a 90-degree pattern constant-directivity horn, with the crossover frequency being where the midwoofer's radiation pattern has narrowed to 90 degrees. So there is no discontinuity in the off-axis energy. Assuming I use a horn that has no characteristic "horn signature", imo this approach is conducive to long-term fatigue-free listening.

Other designers have other techniques for dealing with this issue; mine is not the only valid approach. But if you've ever spent time with a speaker which initially sounded impressive and then over time became fatiguing, think about it in terms of what the off-axis energy was like in the crossover region between midwoofer (or midrange) and tweeter. In many cases, I think you'll conclude that there was probably an excess of off-axis energy at the bottom end of the tweeter's range.