Do we know if adding directivity to the bass frequencies adds to the sound quality?

[sigbergaudio]

Allow me to elaborate/clarify … I am referring to the listener/customer that does not have a dedicated listening room, rather it is a normal listening space, and does not have the need to get that last small percentage of improvement that treatment would provide with a properly designed speaker system (“properly“ also implies built in room EQ by the way). Not all home users want to make their room look like an insane asylum padded cell, nor would they be allowed to even if they wanted by their significant other. A benefit and selling point of the new generation of active systems with cardioid and REQ.

But yes, to achieve perfection, I agree, even with a speaker like D&D, some minor amount of RT may be necessary (emphasis on minor)

To clarify my point as well: Both cardioid and treatment is effective, regardless if you have cardioid or treatment. They complement each other / both give effect regardless if you have one, the other or both.

But cardioid is not magic. So a well treated room and traditional speakers, may surpass the sound of cardioid speakers in a very reflective room. If you however can't or won't do anything special to treat the room, cardioid definitely helps.

 

[NTK]

Someone did a doctoral thesis on this.

https://openresearch.surrey.ac.uk/esploro/outputs/doctoral/The-Influence-of-Loudspeaker-Directivity-upon/99511687202346

Abstract:

 

[MKR]

To clarify my point as well: Both cardioid and treatment is effective, regardless if you have cardioid or treatment. They complement each other / both give effect regardless if you have one, the other or both.

But cardioid is not magic. So a well treated room and traditional speakers, may surpass the sound of cardioid speakers in a very reflective room. If you however can't or won't do anything special to treat the room, cardioid definitely helps.

Cardioid is “magic” vs traditional designs in many aspects. But yes, in a highly reflective room no speaker design can 100% compensate.

And I am gonna beat a dead horse here, one I know that you seem to disagree with, but cardioid down to around 40Hz is especially “magic”

 

[Trdat]

This is pretty much what Directiva r2 is meant to test.

The main question is whether the slots cause a different tradeoff than getting directivity down to hundreds of hertz. The room element weighs in too. A better question may be whether room treatment is more productive than seeking controlled directivity in a speaker's upper bass. Room treatment is certainly more flexible but perhaps not as aesthetically acceptable.

As speakers integrate DSP more and can adapt to the room, suspect this will become the norm. There are a few hifi speakers that allow a glimpse into this future but are pricey for now.

Don't get the slots thing to be honest?

 

[Trdat]

Cardioid is “magic” vs traditional designs in many aspects. But yes, in a highly reflective room no speaker design can 100% compensate.

When you say cardoid "is magic" do you mean specifically cardoid design or any design that has controled directivity down to a certain hz?

 

[MKR]

When you say cardoid "is magic" do you mean specifically cardoid design or any design that has controled directivity down to a certain hz?

Good clarifying question … yes, to state differently, indeed any design with well controlled directivity. Even better, user controllable variable directivity depending upon room characteristics and listening preferences

 

[Trdat]

Good clarifying question … yes, to state differently, indeed any design with well controlled directivity. Even better, user controllable variable directivity depending upon room characteristics and listening preferences

I am totally okay that the thread diverged, ultimately it is for educational pruposes but the orignal intent was to get an idea or at least thereabouts if adding a bass bin to control directivity for mid bass would provide audible improvement. At least it seems you would agree to this statement is that correct?

 

[MKR]

I am totally okay that the thread diverged, ultimately it is for educational pruposes but the orignal intent was to get an idea or at least thereabouts if adding a bass bin to control directivity for mid bass would provide audible improvement. At least it seems you would agree to this statement is that correct?

Yup, fully agree, and sorry for the divergence

 

[DVDdoug]

I'm not an acoustical expert but 100Hz has a wavelength of about 10-feet so I don't think "directivity" (in the bass range) has any meaning in a normal living room. Standing waves are usually the issue in the bass range.

 

[sigbergaudio]

And I am gonna beat a dead horse here, one I know that you seem to disagree with, but cardioid down to around 40Hz is especially “magic”

I don't necessarily disagree with that. Where / how / with what have you tested that in a domestic setting?

 

[sigbergaudio]

Cardioid is “magic” vs traditional designs in many aspects. But yes, in a highly reflective room no speaker design can 100% compensate.

No commercially available cardioid designs get anywhere near 100% attentuation to the side or rear as far as I know. I'm not trying to downplay the effect (that would be very counterproductive since I build cardioid speakers), but let's be realistic.

The effect in a normal domestic listening situation is significant, but the reflections aren't removed 100%.

With the Sigberg Audio Manta the claim is more than 40% reduction in energy to the side, and more than 60% reduction in energy to the rear compared to a traditional speaker. This is certainly significant, but the reflections don't go away alltogether - so room treatment will still have additional (and positive) effect.

 

[Rick Sykora]

Don't get the slots thing to be honest?

see this thread: https://www.audiosciencereview.com/...adiation-via-lateral-slots-like-d-d-8c.37863/

Erin’s review of Dutch and Dutch 8c illustrates the commercial potential.

p.s. as does the Sigberg Manta!

 

[Flaesh]

15inch midwoofers and curious if my next DIY design employs directivity for the midwoofer would

Blumenhofer Acoustics' 40ies Anniversary

www.blumenhofer-acoustics.com

 

[phoenixdogfan]

I know this is going to be a stupid question but I'm going to ask it anyway. Is it possible to retroactively create a cardoid midbass using DSP? Theoretically, I mean. Well, maybe not. Does Dirac's ART with it's use of other speakers to "help out" and cancel some in room noise at least start to create an in room, midbass cardoid effect?

 

[617]

So no measurement comparing monopoles (sealed) dipoles (panels and bass reflex) and cardioid below schroeder?
This is an interesting question. Intuitively it seems like radiation pattern wouldn't make much difference in the modal frequencies; the waves are still vastly larger than the space.

The advantages of cardioid alignment in outdoor and large space PA systems don't apply to domestic spaces.

This is a marketing point used by Genelec (and Sigberg? And perhaps some dipole providers too) and I haven't seen any data.

To be precise, 'better' in this frequency range would mean less peaks and valleys compared to monopoles and dipoles.

Geddes is dismissive:

I think the advantages for directivity approaching schroeder are fairly obvious, and if you surpass that region by a bit, no problem, but let's not forget that cardiods and dipoles are an expensive way to create bass, especially if they don't work better than distributed monopoles.

 

[Rick Sykora]

As have been having some deja vu over this thread, NTK's post jostled my memory. See here...

Controlled directivity speakers

I was reading @TimVG @Floyd Toole comment about the importance of directivity control as low as possible (see #1,030 ). I had thought that only Dutch & Dutch and Kii were providing that kind of product. But in looking through @pierre's website, I stumbled across the Revel F226Be...

www.audiosciencereview.com

I had comparable questions about directivity while working on the Directiva requirements. @TimVG cited this paper:

https://aaltodoc.aalto.fi/server/api/core/bitstreams/53118e62-e0d0-4a6d-949b-b74049a069e4/content

 

[MKR]

View attachment 337447

Blumenhofer Acoustics' 40ies Anniversary

www.blumenhofer-acoustics.com

View attachment 337454

Never heard of Blumenhofer before. Took a look at their website, nice looking speakers!

 

[sigbergaudio]

As have been having some deja vu over this thread, NTK's post jostled my memory. See here...

Controlled directivity speakers

I was reading @TimVG @Floyd Toole comment about the importance of directivity control as low as possible (see #1,030 ). I had thought that only Dutch & Dutch and Kii were providing that kind of product. But in looking through @pierre's website, I stumbled across the Revel F226Be...

www.audiosciencereview.com

I had comparable questions about directivity while working on the Directiva requirements. @TimVG cited this paper:

https://aaltodoc.aalto.fi/server/api/core/bitstreams/53118e62-e0d0-4a6d-949b-b74049a069e4/content

Interesting study! Conclusion for those who can't be bothered to read it:

"This Thesis has studied the audible effects of increasing the loudspeaker directivity at low-mid frequencies (LMF). A functional prototype of a compact two–way loudspeaker having an increased LMF directivity has been designed and implemented. An AB listening test has been conducted with two loudspeakers A and B, where the LMF directivity was the only varying characteristic between the loudspeakers A and B. The listening test results were statistically analysed, showing significant improvements in clarity, absence of sound colourations, transient reproduction and accuracy of the virtual sound images improved with increasing LMF directivity. Sound quality impairments were not detected when the LMF directivity increased. The LMF directivity was the main factor contributing to the subjective assessment of the sound quality"

 

[617]

That study is interesting. If you look at the frequency response, the room is doing the same thing to both speakers:

So directivity does not seem to impact over all frequency response. However, room reverberation is different:

So, the improvement is not due to less modal excitation but rather different decay characteristics
. The more directive speaker set up has around 5db less reverb in effect, very impressive.

For those curious, the directivity was accomplished by using two identical speakers with offset and delay and some other filters to create a cardioid effect, much like a PA sub array.

 

[gnarly]

Aaargh....the instant I see a study with a listening distance of 1m,.....i quit reading.
Anybody else feel this way?

1m can't even get into the acoustic far field, unless the speaker is a pretty small bookshelf.