What is Loudspeaker Directivity?

[@jarodreddig63]

I use the JTR NOESIS 212 for LCR in my dedicated theater. Was really cool seeing them used as an example! Best speaker I’ve owned.

[@optimusvader7823]

AWESOME video. 🔊🙋🏻‍♂️. Thank you Gene and Matt for always teaching us the way of learning the technical part of this amazing Hobby !

[@great100m]

Learn something every time - thanks ! Old ears and damaged hearing and, for me, dialogue clarity is everything for HT. Looking for best L/C/R speakers to replace my existing Elac Debut 2.0 (5.2 BS) speakers in 5.1.2 system for good dialogue. Have heard that speakers with "good directivity" make for better clarity and look forward to your comments in upcoming videos.

[@m.r.3128]

Be excellent to see this imaging modelling for an Open Baffle vs. a box speaker 🔊

[@PoesAcoustics]

M. R. I agree. I don’t have an easy way to model that however. In practice they have a dipole radiation pattern and if done right can mimic a cardioid pattern which narrows dispersion to the sides. Depending on the back treatment they can have a strong or weak rear radiation. Some argue that these are superior speakers but I don’t personally buy it. I don’t see a good reason for it to improve sound. Lots of ways to modify directivity without incurring the problems you often see in an open baffle arrangement. It’s important to keep in mind that none of these concepts are poorly understood or magical. We know how they work and why. Open baffle speakers incur a huge sensitivity penalty with a substantial loss of efficiency at low frequencies. In addition the lack of loading leads to a rise in distortion. As such you have to offset this by making the speakers much larger and using a lot more bass drivers. You end up with a huge speaker that performs like a little one.

[@timalanthwaite4759]

Consistently excellent information from this channel. Well researched and presented. Thank you.

[@bas7es]

Audioholics is a excellent resource of real know-how. Great video with the essence and importance of controlled directivity. Unfortunate that there was no mention of the Genelec ONE series or the Kii three’s which are designed for excellent directivity control. A home theatre build with those speakers combined with room correction have many merits.

[@brkly99]

Very good discussion! Looking forward to the follow-up parts.

[@Odyofil]

Thank you for this great talk. What about KEF speakers with UNI-Q?

[@SwirlingDragonMist]

Well Shiver me Whiskers! Ha ha ha. isn’t this just the coolest topic ever! I’m glad dispersion is getting it’s due. I’ve got 6 mirage omni-150’s and several “The wave” curved step aerobics platforms which I’ve been thinking of putting in between them as polyhelindrical diffusors, I also have absorbers which I think would be probably be good behind the speakers, with the polyhelindrical pieces basically seeming together the speakers in 7.0 surround setup. I look forward to hearing how acoustic treatments can be used with speakers of different directivity characteristics to create different sonic fields.

[@deanedgx]

Another great video guys. Defo will be subscribing

[@ChannelBri]

Great subject, terrific presentation, thanks!

[@fernandozegarraaudio8144]

Matt, I would like you to answer the following question. I tell you I am a big fan of listening to live music of the symphonic type for more than 20 years I know we all have different tastes, in my case I like to sit in row F - H (the seats start from A to the row closest to the orchestra) or row 8-10 in concert, this because the bodies of the musicians do not interfere with their musical instrument and I am already high enough so that the treble is not interrupted (closer to the orchestra I am below the midline of the musicians). So the violins, violas, oboe , flutes, trumpets, clarinets, etc., sound better and I have a viewing angle of around 45 ° -60 ° and if it is very easy to locate where the violins, cello, trumpets, bassoons, etc. are, with eyes closed. Even in the case of singers such as sopranos, mezzo sopranos, tenors and baritones, their location is very precise. Unfortunately in the recordings, there are very few of good quality that will be able to faithfully present the orchestra's disruption, but when it is achieved it is MAJESTIC. Only if you sit further back is where the location is lost and a more mono and non-stereo like sound is obtained, in addition to the fact that the direct sound is taken away and many of the reverberation of the room settle. So the question is: It is better to acoustically correct the room in order to listen to the recorded orchestra (really any recording) with a flat response (narrow) and to be able to hear the reverberation of the room as the audio engineer wanted to show instead of trying to have a speaker with higher dispersion? In my experience, while the listening room is better controlled, listening (if the recording is good) is better enjoyed and the passages of the orchestra are better appreciated. Thank you.

[@TheDanEdwards]

" I like to sit in [selected seats in a concert hall]. So the violins, violas, oboe , flutes, trumpets, clarinets, etc., sound better [...] and [ ] it is very easy to locate where the violins, cello, trumpets, bassoons, etc. are, with eyes closed. Even in the case of singers such as sopranos, mezzo sopranos, tenors and baritones, their location is very precise." "[Is it] better to acoustically correct the room in order to listen to the recorded orchestra (really any recording) with a flat response (narrow) and to be able to hear the reverberation of the [original] room as the audio engineer wanted to show instead of trying to have a speaker with higher dispersion?" - good question but Audioholics appears to not answer comments after a few days of posting. The problem I have found, as have so many others, is that if you want to listen to recordings of large groups (whether a symphony orchestra or a large dance band or even a marching band) that a 2-channel system is limited by scale and listening room. J. Gordon Holt famously used to listen with very large Sound Lab (electrostatics) speakers, panels which are huge by what most people buy. I myself played with Magnepans (which are probably not as forgiving as the Sound Lab speakers) and by sitting in the near-field of the speakers (so that the direct radiation hits the ears with enough time before the in-room reflections) one can get a sense of both soundstage, fair imaging (the placement of individual musicians), and the grandeur of the size of the original ensemble. But playing with large dipole speakers is not for everyone's tastes.

[@LifeAsISeeIt]

Great video. Lots of good information.

[@Nightjar726]

God I wish there was more info and research on this topic. Any new breakthroughs in tech for this?

[@DigitalDonAV]

Great video!

[@sudd3660]

i think there is a way to get that intimate detail sound and the spatial cues, with wide dispersion speakers placed far from walls and close to listener.

[@SwirlingDragonMist]

sudd That’s really cool! I’m going to try that next pandemic when I get the time ha ha ha Sometimes I like to point my speakers into corners to energize the sound in that region for a spatial feel. Or toe them really wide and listen to the sidewall reflections.

[@PoesAcoustics]

sudd hey so I might agree and disagree. If you are suggesting it’s possible to get the best of both worlds, I probably would not agree with that. I would argue that setting wide dispersion speakers up in this way increases the ratio of direct to reflected sound. This would create a soundstage most similar to that of a controlled directivity speaker. However, it is necessarily fin going to reduce the level of lateral reflections and that would reduce spaciousness and apparent source width. Sadly you can’t have both maximized at the same time. But you can certainly play with reflections to balance out a preferred sound.

[@JosephCrowesDIYSpeakerBuilding]

Wonderful content guys. 👌

[@isak6626]

A question about toe in: in the manual to my speakers, I'm told specifically not to toe in the speakers because the manufacturer (Dali) follows "a wide dispersion principle". Everyone else keeps saying that you should toe in your speakers. How come Dali, which is a well renowed speaker manufacturer, specifically recommends against this? What could be the reason? Whose recommendation should I follow?

[@overgme]

You should try both, and see which you prefer. Dali would probably know best about what position is likely to sound best, but your particular room setup is going to play some role that Dali just can't predict. I own a pair of BMR's like those referenced in this video . . . super wide and excellent dispersion. Their creator, Dennis Murphy, also recommends pointing these speakers straight ahead, just like Dali. I have no doubt whatsoever that Dennis knows what he's talking about (he didn't luck into designing some of the best measuring wide dispersion speakers Audioholics has ever measured). Still, in my particular room, a touch of toe in give me the best balance of a wide soundstage with good imaging. So I'd probably start with Dali's recommendations, but if you can, play around with a little toe in and see if it suits your room and preferences better.

[@isak6626]

@@overgme Thank you for this elaborate answer. I'll definitely have a go at that. I was curious to know the reason for their recommendation. In other words, is there a downside to toe in if the speaker has certain characteristics?

[@overgme]

The "best" speaker positioning is going to be a factor of three things, 1) the speaker, 2) the room, and 3) user preference. So there is no one sized fits all answer to your question. But as a very, very, very generalized principle, certain speakers are designed so that the best balance of soundstage and imaging occurs when the speakers are pointed straight ahead. Once again, as a very general guideline, wider imaging speakers often work best pointed straight ahead. So Dali's recommendations would be consistent with this idea. So for certain speakers, toeing them in too much (or even at all), might shrink your soundstage, making it sound like every instrument (or sound) is coming from the middle of your speakers, rather than across the width of your room (and depending upon the room and speakers, sometimes they can even make it sound like they're *wider* than your room).

[@isak6626]

@@overgme thank you. I guess I'll have to try to find out!

[@geickmei]

@@isak6626 Sit in front of the right speaker. Play a center soloist recording. She will be off center toward your side. Now gradually toe both speakers in until the soloist recenters. No more "hot seat."

[@mb-electricalservices]

Gene/Matt - I have a difficult room where placement is concerned which means my right speaker will be within a foot of a sidewall and I have to live with that but, having said that, it shouldn't stop me from enjoying good sound! My question is, I am considering buying either a waveguided REVEL or the Philharmonic BMR (which has superwide dispersion). Would either of these be a poor choice for my situation? What would you recommend would work best in my particular case. I have no room treatments and cannot install any as it's a living room (lounge). I use an Anthem STR preamp for room correction BTW. I know you don't want to be seen to recommend a particular product but it's more the dispersion I'm interested in and how that would work with my room. Thanks, Mike.

[@asadhafeez7713]

I think (and hope) that JBL rules the speaker manufacturer industry regarding speaker directivity, imaging and clarity thanks in part to their experience in HF compression drivers as well as mid/low driver technology. But I also think that a speakers directivity negatively affects even dispersion (the well sought-after sweet spot) in a home cinema environment. Achieving both is the goal of course. True listening pleasure involves dynamics and in-your-face sound regardless of the seating position.

[@kirkcunningham6146]

I have the JBL Studio 590 and they have very good off axis response.

[@PoesAcoustics]

Asad Hafeez im not sure what you mean? Directivity is just a name for how a speaker dispersed sound over all angles about the speaker. JBL doesn’t have a special market on this by any means. If you are referring to the consistency of speaker directivity over all angles, JBL tends to focus on narrow dispersion where as Revel is more medium/wide. Vivid audio is a good example of a company that prioritizes wide and does an excellent job of it. Speakers can use any of these methods and get a very good or very bad response at various angles. My experience is actually that speakers with good controlled dispersion have the most consistent response and largest sweet spot. Wide dispersion narrows the sweet spot which I will discuss in the future.

[@asadhafeez7713]

@@PoesAcoustics Exactly. That's just what I was thinking... "Controlled" directivity vs just "narrow" directivity". Much depends on the design of the horned system which would ultimately decide the coverage area now wouldn't it? Thanks.

[@asadhafeez7713]

@@kirkcunningham6146 Yes I have a JBL Audio 580/520. I am yet to experiment with it's coverage area (mainly horizontal).

[@gerritgovaerts8443]

The absolutely impossibly wide is a very possible omnipole . You can buy those from MBL

[@SpiderMan-aa]

You mentioned the jtr 212 having good dispersion down to 1khz but there website says the crossover point is 500hz. I'm assuming they improved on the crossover after your feedback from your review. P.s. I'm excited to buy these at some point due to your review.

[@PoesAcoustics]

Well a crossover point doesn’t automatically dictate directivity alone. A waveguide has a lower limit that is largely a function of its mouth diameter. So with a waveguide based speaker you can achieve a flat DI over an extended range in one of two ways. First is that you can place the crossover below the point the woofer dispersion narrows. For that to work the waveguide must maintain control to at least that point. 500hz would require a waveguide that is 24” or more in diameter. All depending on the waveguides directivity angle. A 12” waveguide can generally only control things down to about 800-1000hz or so. One reason why the DI of the JTR falls off below 1khz is because of this. I argued with Jeff about this but came to realize he had a second problem to contend with. An MTM creates a vertical lobe error causing a big dip and it happens right at 1khz. So 500hz is ideal to avoid that dip. How could you fix this and make the JTR even better (all these criticisms are relatively minor as all speakers have compromises and this one is minor compared to many other possible issues.) The answer to how to make it better is tricky and something I’ve been thinking about. I believe there are two good options. The first would be an elliptical oblate spheroid waveguide. Not like the SEOS, but one with much larger dimensions and a more oval shaped mouth. Something that is 18”-20” wide but only 12”-14” tall. From there you keep the woofers as close as possible. Might even cut into the waveguide so the woofers can be closer. Raise the crossover point to about 700hz or so. In this design you get a tiger vertical response that still matches well with a good horizontal response whose DI should be flat to 700hz. To get to 500hz you switch to 15” woofers. Want it flatter than that to even lower? Cardioid loading of the bass drivers. But that is no free lunch. Besides being tricky to get right and expensive to design and produce, it requires twice the parts and ideally would need to be an active design.

[@rb032682]

"Beam steering" of the audio is also possible with individually controlled drivers.

[@BoredSilly666]

Could you increase the size of the mouse cursor so its easier to follow around please? Thanks

[@APSuk2]

A guide on how to measure the on & off axis response of your own speakers at home (if possible) would be very useful. Not everyone can find measurements online for their speakers so they have no idea what dispersion characteristics they have. You really are working blind if you don't have this information.

[@sudd3660]

biggest problem for doing this at home is space, like gated response work if you use mic and go indoors and place speaker in the middle of a large room. A quick and dirty way i know of without equipment is using a tone generator like www.szynalski.com and put your head close to one speaker and mute the other speaker, with some sweeps and angles you can hear the dips and problems the speakers have.

[@PoesAcoustics]

Master Mech we could consider this. It’s tricky to do inside without knowing what to look for. Most people do it wrong when they first get started and it is hard to know you made a mistake without someone to guide you. I will think about this for a summer project.

[@APSuk2]

@@PoesAcoustics Hi Matthew, I fully appreciate that it is not a straight forward process that everyone will be able to do but it would be great to know how these measurements are taken & the efforts involved. Many thanks for your time & reply.

[@PoesAcoustics]

Master Mech do you want to see how to measure in your room in a way that is easiest for a lay person, or how we measure? They aren’t the same thing.

[@APSuk2]

@@PoesAcoustics Well my initial thought was for a guide on how to measure at home if possible as I would like to find out if my speakers are pretty good or total junk but it seems that this is not viable? I mean if the results you will glean from measuring at home are not accurate enough to ascertain this then its not worth the time & effort. I would be willing to take my speakers outside to measure if it was necessary, I see people placing speakers on top of ladders to avoid reflections? I have very limit knowledge in this area so I have no clue what is or is not possible at home.

[@kirkcunningham6146]

I have the JBL 500 Series, the Studio 590's and the 520C Center. They have excellent off axis response. No honkiness with these...

[@bobrouleau7410]

What is the directivity of a piano or violin I wonder ...certainly not highly directive are they?

[@PoesAcoustics]

Porsche Maven the directivity of instruments is irrelevant to the proper directivity of speakers. The way that two speakers reproduce a recording of a violin requires different characteristics than that of the original violin itself. Basically that isn’t how the reproduced soundscape happens and would be the wrong way to think about it. Speaker companies have tried to argue for designing speakers using tone woods and enclosure designs or directivity that matches real instruments. It’s marketing nonsense. It makes nearly no scientific sense to try to compare an ideal speaker to that of the original instruments. There is no denying that If your goal Is the most faithful reproduction of sat a piano in your room, The only way to truest achieve that is to buy a player piano (or the modern equivalent) and put that in your room. On the other hand, if your goal is to reproduce a wide range of recorded music, then using speakers optimized to mimic a piano will not give you the most ideal results in most scenarios.

[@travisb4397]

All he asked was 'whats the dispersion pattern of an instrument' I think that's a fair question. After all, don't most speaker companies claim their speakers sound like the real thing!

[@PoesAcoustics]

travis bastian and my point was that this is a common myth. That a speaker should behave like the instruments it reproduces in order to be a convincing surrogate in reproducing that instrument. You can sound like the real thing without behaving like the real thing. If the goal to accurately reproduce a violin requires that the speaker behave just like it, then we are going about it all wrong. Violins have a somewhat cardioid radiation pattern. More sound comes from the back and top than the sides. The dispersion varies with frequency with an upward facing lobe at higher frequencies. How they radiate into the room depends heavily on how it’s played and in what room. You all are giving me an idea though. We should cover this in a video. It’s really a very in depth topic.

[@SwirlingDragonMist]

So the strings themselves are like line arrays, so they radiate strongest perpendicular to that axis of the string. They vibrate in like a circular spiral, like a jump rope, but it’s like a hundred jump ropes all lined up and shrank down. The instrument has it’s own resonant cavity with openings that propel the sound back out of the opening in a 180 degree radiation pattern. The shape and width of the surface around the opening can influence the the radiation pattern, as the wavelengths shorter than the surface will rebound off of it perpendicularly, but those frequencies longer than the width of the surface will wrap around it. Refresh rates on video can help visualize strings. kzbin.info/www/bejne/boqqgqCMaLOrg6s

[@gerritgovaerts8443]

@@PoesAcoustics Violin directivity is certainly freq dependent but not cardioid I think . See this pdf for its measured dispersion : architexte.ircam.fr/textes/Vos03a/index.pdf To me it seems to go from nonopole to dipole to quadrupole like and finally to octopole like . Why is it a myth that a speaker should replicate the dispersion of the replicated instrument ? It sounds logic to me that the ultimate replication is the exact recreation of the sound field .

[@johnsweda2999]

Measurements are not everything like in the b&w at the end of the day it's how it sounds hopefully sounds good. and it's meant for 2-channel listening not cinema. Let's not get hung up on measurements that makes for poor sounding system can do. Well I think linkwitz addressed this in his LX Mini omni-directional, where he mounts the Twitter midrange at Centre Point pointing towards the listener by having that balance of omni-directional in the mid-range to low Range and directional at the same time in the mid-range is the synergy between the two drivers to give you space but directional as well at the same time

[@Audioholics]

Agreed, I've been to Bowers & WIlkins factory and heard the 800 D3 and 700 series and found the demos to sound very good.

[@johnsweda2999]

@@Audioholics hi can you remember what amps they used at the B&W factory would that have been chord any chance

[@PoesAcoustics]

Audioholics but would they sound better than something like the Revel Ultima Salon2?

[@Odyofil]

Thank you for this great talk. What about KEF speakers with UNI-Q?