Do high-efficiency speakers really have better 'dynamics'?

[Tom Danley]

Does this +3 dB (relative to the summed separate radiations) from two close-coupled radiators extend to the power response? My understanding is that close-coupling generally results in pattern-narrowing in the plane the drivers share such that the power response remains the same, BUT I'm now sure how that would apply at frequencies where the two drivers are less than 1/4 wavelength apart.

Hi Duke
A single woofer, when it's producing a sound who's wavelength is much larger than it is will have a spherical radiation pattern and at distance X, will produce X SPL with X power.
If you have two identical woofers, less than 1/4 wl apart, they also produce a spherical radiation pattern but the SPL is now +6dB higher, over the entire sphere at the same distance. This coherent addition can be demonstrated by inverting one of the two woofers and then they cancel each other out (like the effect of not having a cabinet).

If you separate the woofers to some distance greater than about 1/3 wl, they become individually sources and they radiate in a pattern of lobes and nulls (an interference pattern) governed by the separation and wavelength being produced. If you are equidistant from the two woofers, at that point in space on axis you still get the +6 while the total energy is +3dB more than one source..
This is a stack of polar plots for two sources less than 1/4 apart at the bottom and getting progressively farther apart in wavelength as the frequency is increased

 

[Schollaudio]

Hi Duke
A single woofer, when it's producing a sound who's wavelength is much larger than it is will have a spherical radiation pattern and at distance X, will produce X SPL with X power.
If you have two identical woofers, less than 1/4 wl apart, they also produce a spherical radiation pattern but the SPL is now +6dB higher, over the entire sphere at the same distance. This coherent addition can be demonstrated by inverting one of the two woofers and then they cancel each other out (like the effect of not having a cabinet).

If you separate the woofers to some distance greater than about 1/3 wl, they become individually sources and they radiate in a pattern of lobes and nulls (an interference pattern) governed by the separation and wavelength being produced. If you are equidistant from the two woofers, at that point in space on axis you still get the +6 while the total energy is +3dB more than one source..
This is a stack of polar plots for two sources less than 1/4 apart at the bottom and getting progressively farther apart in wavelength as the frequency is increased

Tom, at what point in space is adjacent speaker distance important? Say we have two speakers one WL apart at the enclosure but overlapping at the listening position. How would they combine?

 

[Duke]

Hi Duke
A single woofer, when it's producing a sound who's wavelength is much larger than it is will have a spherical radiation pattern and at distance X, will produce X SPL with X power.
If you have two identical woofers, less than 1/4 wl apart, they also produce a spherical radiation pattern but the SPL is now +6dB higher, over the entire sphere at the same distance. This coherent addition can be demonstrated by inverting one of the two woofers and then they cancel each other out (like the effect of not having a cabinet).

If you separate the woofers to some distance greater than about 1/3 wl, they become individually sources and they radiate in a pattern of lobes and nulls (an interference pattern) governed by the separation and wavelength being produced. If you are equidistant from the two woofers, at that point in space on axis you still get the +6 while the total energy is +3dB more than one source..
This is a stack of polar plots for two sources less than 1/4 apart at the bottom and getting progressively farther apart in wavelength as the frequency is increased

Of course, where they add in-phase the summation will be +6 dB, and elsewhere something less. I knew that... just didn't apply it. Thank you for taking the time to explain something I should have realized on my own!

Interesting 3-D plot, I've only seen "slices" of it, saved it for future reference.

THANKS!!

 

[Chromatischism]

I suspect it can be traced to better acoustic mass loading/impedance matching in both cases-in the one case a super light element interfacing with air, and in a horn, the driver being loaded with a larger, more massive volume of air. Maybe, it's like being in the proper gear.

I'm always about coming up with objective ways to measure and test hypotheses, so air pressure measurements would show this, right?

 

[audio2design]

I think objective dynamic range and the perceived “dynamics” as described by some/many listeners are not the same thing.
Whether this is the result of artefacts/distortion or some other thing I cannot say. I tried to elaborate on this in an earlier post but was misunderstood.

I think they are. If not, then you are not measuring the right things.

 

[audio2design]

I suspect it can be traced to better acoustic mass loading/impedance matching in both cases-in the one case a super light element interfacing with air, and in a horn, the driver being loaded with a larger, more massive volume of air. Maybe, it's like being in the proper gear.

You just defined efficiency ... unless you can prove compression, but that would show up as distortion which is easily confirmed.

 

[tuga]

I think they are. If not, then you are not measuring the right things.

You are being tricked by the word "dynamic". But I agree that measuring HD and IMD distortion at high SPL might be measuring the wrong thing.

 

[fineMen]

I'm always about coming up with objective ways to measure and test hypotheses, so air pressure measurements would show this, right?

You could get away with just the lowest of measurement level, namely nominal, see wiki =>https://en.wikipedia.org/wiki/Level_of_measurement

This is regarding its requirements far below a measurement of relative SPL degradation over input. It seems only so, that some people ask for counter-proof, but don't hand over any criteria, how to test their (!) claims.

 

[fineMen]

You are being tricked by the word "dynamic". But I agree that measuring HD and IMD distortion at high SPL might be measuring the wrong thing.

C'mon, it is always something else, right?

 

[audio2design]

You are being tricked by the word "dynamic". But I agree that measuring HD and IMD distortion at high SPL might be measuring the wrong thing.

Magic will get you no where. Your ears don't respond to magic, they respond to pressure waves travelling in a certain direction.

 

[JRS]

I'm always about coming up with objective ways to measure and test hypotheses, so air pressure measurements would show this, right?

I like to believe yes and with the arrays of miniature mics being produced, someone should try it if it hasn't been. I totally believe in the effect, and therefore assume that there is a measurable, physical difference in the Φ function. Smoke or some aerosol cleverly dispersed and captured on ultra fast video should also reveal a difference. For the record, align arrays seem to have that characteristic as well. I wish I know more about the physics of sound, and have no doubt that those who do can explain to me why "instantaneous" volume-velocity must be the same for all transducers producing the same dB.

It's most peculiar that so many of us have experienced it, yet no one can adequately explain it.

 

[tuga]

Magic will get you no where. Your ears don't respond to magic, they respond to pressure waves travelling in a certain direction.

You're the one talking about magic. All I am saying is that the listening assessment needs to be correlated with measurements but what people are describing doesn't seem correlate directly with any of the measurements; perhaps they are not verbalising it in a way that is comprehensible. Perhaps we could be a little less blinkered and try to understand what they mean by sounding 'dynamic', 'lively', or whatever. If that's not straying too far from the dogma...

 

[audio2design]

You're the one talking about magic. All I am saying is that the listening assessment needs to be correlated with measurements but what people are describing doesn't seem correlate directly with any of the measurements; perhaps they are not verbalising it in a way that is comprehensible. Perhaps we could be a little less blinkered and try to understand what they mean by sounding 'dynamic', 'lively', or whatever. If that's not straying too far from the dogma...

What measurements would be my question? The very limited set of measurements typically taken of speakers that rarely reveals what they are doing when pushed nearer to their limits? How many IM plots for speaker have you seen at high volume? Any volume?

The only way to "understand", is blind testing to validate impressions, and measurements at the same time so that you can correlate impressions with what is actually happening. But one must accept that the parameters are somewhat limited even in a complex sound field. You also must use the same music to compare systems. Some music does have peaks well above average and not every system can handle that. That will show up in measurements (the right measurements).

Match small monitors designed to play with a sub, i.e. not hobbled by unnecessary low frequency extension killing their efficiency where used, and place them behind a screen with said subs and ask people what they are listening too. The assumption will be large full range speakers. I know, I have done it. The efficiency didn't make them more dynamic, it just made them louder, or capable of more loudness without distortion.

 

[fineMen]

... that the listening assessment needs to be correlated with measurements but ... try to understand what they mean by sounding 'dynamic'... the dogma...

... physical difference in the Φ function. Smoke or some aerosol cleverly dispersed and captured on ultra fast video ...
It's most peculiar that so many of us have experienced it, yet no one can adequately explain it.

In science there is room for counter-proof only. You might refer to the very 'dogma', that there never is positive truth. Science keeps testing hypothesis longing for counter-proof, in order to find new fields for progression. If counter-proof is not found, try again.

I give You counter-proof.
(A) cute little speaker, 9 liters of internal volume, 3-way (yes!), cheap bass, cheap midrange and boringly regular tweet. Eta: 80dB/Watt, passive x-over
(B) man-eating 90liters reflexed, 3-way with highly qualified 12" (twelve) midrange and wide dispersion compression driver / waveguide on top. Eta: 95..110dB/Watt referred to the individual drivers *in their enclosures*, active x-over

(A) and (B) show, within their specific operating limits the same dynamic. Despite the crass differences no difference.

... just made them louder, or capable of more loudness without distortion.

Yes, both were played at reasonable average level with 'material' showing above average input level dynamics, e/g Joanna Newsom. With bass-heavy stuff like Infected Mushroom, the small 3-way whilst being just as dynamic as the other at lower levels, soon gave up with higher levels. But that was then beyond the design limits. I know where they were, because I designed them to behave like that, and they exactly followed the designed-in rules. Same dynamics, but the bigger could do just 30dB louder, right?

As You eagerly reqeust (!others!) to find out *scientifically* what is going on, You might develop another theory. Counter proof given, hypothesis debunked, success in the end, happy new funding ...

Mind You, science doesn't accept exceptions. Every exception tells, that the theory is plain wrong, incomplete at the very best.

Again, it is time for You to rework the theory before You ask for "scientific proof", which again by basic principles doesn't exsist anyway. Or is this conversation meant to only entertain ourselves with stereo small-talk? I've recorded bats in my backyard this summer. Didn't know that my measurement mike goes up that high! Proven, that these fancy voices have a very high directivity. I should train my hearing accordingly for the next summer to come. 40kHz is something to achieve, though. Beryllium tweet needed, what do You think?

 

[Slayer]

I was happy to see this topic brought up, as to which is correct or not, i have no scientific data either way. Rather only subjective or opinionated thoughts. I won't or cant say most high sensitive speakers have better dynamics, however i do feel ( again no scientific proof ) that high sensitive horn loaded and or compression driver systems, seem to have better high dynamic range.
This would apply to quality versions and properly calibrated systems of course. Those of you with or have heard some good horn systems may know what i speak of, yet it is one of those things in audio listening, subjectively yet trying to be objectively, is hard to put into terms.

What i will say is do some experimenting if you have multiple speakers to compare. A good piece of music to do this audition on is one of Wagners pieces which may not be so commonly known to all the listeners here. The dynamics are amazing, and at some points should startle you if you have dynamic speakers. I have found over the years, there are some things you here on horn systems that are not noticed with conventional speakers. Have a listen and hopefully you will see what I mean. Apply one watt to your speakers and this should not only blow you out of the room, it should sound beautiful while doing so. Anyhow, happily listening and great topic.

Amazon HD Music: Wagner: Gotterdammerung, WWV 86d-Concert Version/Dritter Aufzug, Siegfrieds Funeral March Metropilitan Opera Orchestra & James Levine

 

[Chromatischism]

What i will say is do some experimenting if you have multiple speakers to compare. A good piece of music to do this audition on is one of Wagners pieces which may not be so commonly known to all the listeners here. The dynamics are amazing, and at some points should startle you if you have dynamic speakers. I have found over the years, there are some things you here on horn systems that are not noticed with conventional speakers. Have a listen and hopefully you will see what I mean.

What if the horn is simply doing pattern control so you are getting less reflected sound and can hear more detail?

 

[Slayer]

What if the horn is simply doing pattern control so you are getting less reflected sound and can hear more detail?

That is entirely plausible. Which I can not give a definitive answer to. I do think there is something more to it. I would be nice to determine exactly what it is causing or making this difference in dynamic range appear to happen. Would be nice if some speaker designers will chime and give their technical thoughts on the matter.

 

[audio2design]

What if the horn is simply doing pattern control so you are getting less reflected sound and can hear more detail?

Some of that happens with line arrays and similar "floor to ceiling speakers". Less reflections in poorly controlled room and more detail can result.

 

[audio2design]

That is entirely plausible. Which I can not give a definitive answer to. I do think there is something more to it. I would be nice to determine exactly what it is causing or making this difference in dynamic range appear to happen. Would be nice if some speaker designers will chime and give their technical thoughts on the matter.

I have done "speaker" and acoustic/signal processing work for speakers so I think I would qualify. Working on a side project (not work) on complex directional control. Lots of listening experience in controlled and non controlled systems. All that influences my opinion.

 

[Chromatischism]

Some of that happens with line arrays and similar "floor to ceiling speakers". Less reflections in poorly controlled room and more detail can result.

Like this?

https://www.avsforum.com/threads/radical-speaker-design.3053246/#post-57664532