The Truth on the Biggest Lie about Open Baffle Speakers 

More! Not less! The open baffle has MORE room interaction than a boxed speaker simply because it's firing out of the back of the speaker as well. Those emissions reflect from the walls in the room almost exactly like the ones from the front. The "figure 8" dispersion pattern is mostly an "on paper" concept that goes out the window in a real room. By real room, I mean YOUR room - any small room. As demonstrated with measurements in this video, the room modes are still activated by a dipole speaker. That's because all that takes is for the mode frequency to be present in the room. If it's there, the room will resonate at that frequency regardless of where it's coming from or what's producing it. My listening room has a very strong room mode at 37Hz, and you can clearly see in the waterfall and spectrograph plots that the mode is being energized. That's because the dipole sub is playing that frequency - it's in the room and the room is resonating at the frequency. If you can measure output at 37Hz, then that room mode WILL BE activated. The ONLY WAY to not activate it is to have NO CONTENT at 37Hz at all - zero - a HUGE null. Also as shown in the video, an open baffle speaker is putting a lot of energy out off axis, even out to 90 degrees to the face of the baffle in the so called dead zone where maximum cancellation is supposed to happen. As I said in the video, the output from the rear CAN NOT be exactly the same as the output from the front, and that weakens that cancellation effect at the sides. So the truth is that open baffle speakers are not the physics-defying panacea that a lot think they are. They have more room interaction (and that's WHY they sound different and WHY some of us love them) and CAN NOT solve room mode problems or make room treatment unnecessary.

I enjoy people that are not stupid. 😂. Thanks John this channel is helping me to enjoy my hi-fi even more!!

1. Dipole/Open Baffle systems do not excite room modes as much as typical bass (omnidirectional at low frequencies). This is orientation dependent and due to the null to the sides and top down of the dipole (if you don't have these nulls we are not talking about a dipole). Side to side and vertical axial modes will be highly attenuated for a forward facing dipole loudspeaker because sound energy is not being fed into these axes. (but it is in the front back axis and axial modes in this axis will be excited, dipole orientation matters. Normal bass will excite all the modes but varying in degree with room location). 2. The directivity of the dipole bass means that for the same level at the listener as normal bass the reverberant field (reflected sound energy following the direct sound) is 4.8 dB lower, i.e. 4.8dB better signal (direct) to noise (reflections). 3. 1& 2 result in the dipole bass being cleaner and much less affected by the room and position in the room than normal omnidirectional bass. Normal bass will never provide a sonic improvement on dipole bass unless your preference is for the mud, resonance and, in the case of bass reflex, time smear of the familiar 😀 4. If we also have the midrange and high frequency with dipole or dipolish directivity, this means that, unlike typical audio systems with omni bass and much more directional sound above, the directivity stays relatively constant throughout the full audio spectrum (and, yes, we do want a rear facing tweeter). 5. This results in a number of psychoacoustic benefits (you can't measure these with a microphone) including precedence. The fact that the off axis sound spectrum matches that of the direct sound, because of the constant directivity and unlike typical systems, means that the reflected sound off the room walls mimics that of the direct sound sufficiently that the brain recognizes it as a reflection of the source, not a separate sound, and ignores it (like it is ignoring the presence of the room). So even though you are firing sound energy to the rear of the dipole as well to the front, unlike at the higher frequencies for a normal system, your auditory system essentially ignores this following sound and it is why we can say that the dipole causes less apparent room interaction (how we hear the results) and less real/physical interaction in the bass. Once you are used to the benefits of a well executed dipole system it is hard to go back...

I agree. My lack of room boom when moving from ported box subs to OB subs is probably due to less bass below 30hz. Makes sense. Ironically I don't miss that extension into those low frequencies at all. Even with bass heavy modern music I can still feel the bass punch in my body without all that low extension

Room interactions can be broken down into 2 x categories, pressure and reflections.

John, I could listen to you and your theories all day. You explain things so well. I too am a hobbyist designer and have had a few victories and some losses. Question: Are you familiar with a man named Bill Woods? He was from Warkworth, ON, Canada. He was an expert designer who started on his own but was hired by Yorkville sound to help bring their PA gear to a much higher level. Sadly, he passed away a few years ago. A terrible loss to the industry. Thanks for another great video!

Looks like even Bass has been affected by CANCEL culture.🤣

I've never understood waterfall plots. You made it clear to me in like three sentences. 👍

Hey John, What about first reflections? Since a room's sidewall is often within the null of the figure-eight, there should be at least some impact on the first reflection's arrival time and amplitude at the listening position? If so, might this fall into the "less Interaction" camp? :)

Siegfried Linkwitz went thru thru all these details long ago

You add much clarity and detail to dispute and dispel audio myths. Many people make simple suppositions about listening experiences without any actual measurements to justify or refute their conclusions based upon impressions and not facts. Good stuff John. BTW “Stupid” seems to be the biggest “pandemic” in the world today, it’s expanding and spreading globally so your “watering hole” of reason draws us here to get sips of clear understanding of practical & truthful information. Looking forward to whatever is next.

One of the GR Research OB servo subwoofer options is rare in that the twin driver has one 12" driver facing forward and one back and the enclosure is designed so that they are in the identical position. Servo subs are a topic all to themselves and this is the exception rather than the rule as far as speaker/sub design goes. Perhaps the reflections from the sides of a well designed OB speaker add to their ability to create a good soundstage. This is sheer speculation on my part. I really enjoy these insights/opinion John. Thank you for your willingness to challenge dogma.

I love open baffle speakers but my two 10" powered subs put out more bass than my OB 15" subs. However, the !5's sound cleaner.

I'm not contesting your assertions here, but I don't think most people with OB speakers got into that because they were told that there's less (potentially negative) room interaction with OB's. I have owned, and have been listening to OB speakers exclusively since 2015, because with OB speakers I don't hear any trace of the box/enclosure surrounding the back and sides of the drivers. Plus, most OB design speakers are easier to re-position in the room than box speakers, be they floor standing, or stand-mount. --I currently have Clayton Shaw's "Caladan" OB's, which sound amazing, and are super easy to re-position in my room if desired. I see no logical reason to return to box speakers again.

Hey John, cool to see that you keep doing stuff on the whole topic of speaker room interaction. One thing i have to add. A dipole only has cancelations if the front and rear wave hit each other. In the midrange you need a 10 or 15cm wide baffle for that to happen. The LX521 or ME Geithain speakers have a narrow midrange baffle for that reason. In the case of the wide baffle you have a dipole at lower frequencys and two halfspace radiators front and back at higher frequencys. Thats why you have a wide radiation pattern. With a narrower baffle the radiation gets tighter and the nulls get deeper. Edit: The best way to see how much room interaction a speaker has, is to calculate the directivity at a certain frequency. There are tools for that.

Yeah, I proved for myself that the "less interaction" thing was nonsense about nineteen years ago with my "open baffle" INF10 experiment.

What you get is better interaction with the room with the dipoles. Thing to note is that not every open baffle loudspeaker is a true dipole. It is true that correctly designed dipole radiates as much to the back as it radiates to the front. from lowest of bass to the point where tweeter starts beaming due to size. This puts dipoles into controlled directivity group of speakers. The timbre of reflected sound is the same as direct sound, which is desirable. Also the figure eight radiation pattern puts more energy towards the listener and the wall behind the speaker and nine to the sides, so it actually excites the room less as the classic box speaker. Box speaker is also directional at the top end and omnidirectional at the lower frequencies thereby producing unnatural timbre in room. One downside of dipoles is the need for space. To prevent early reflection (

Jes more interaction with room is good thing with wented box speakers, woofers and better frequency response with less piks and dip especially 60-90 Herz with open baffle 6:06

You are waving your hands a lot. In school the professor called that a "hand waving argument"

I love my duo 2 in vertical open baffle on top of towers 800hz to 5khz cut the dipole peak@ 1,2k with youtube equalizer

Would it be wrong to say that no matter what speaker you use, whether box, OB or any other type, the moment that you change the space they are placed in, the entire experience changes. Same speakers in 10 different rooms means 10 different results. I'm I wrong ? And would it also be wrong to say a cheap speaker can sound almost great depending of where it is as opposed to an expensive speaker in a bad pace ? Just thinking out loud.

literally NOBODY says that OB speakers have less room interaction.

the open baffle speakers don,t excite th hight and width room modes ussualy around 60hz but they still excite the length which is around 30hz.about the midrange i agree they interact more than convential speakers.

I had no idea that anyone actually thought that. Isn’t it obvious that theres more room interaction? 🤷🏻‍♂️ Can’t anyone hear that?

Is there any advantage to 2 tweeters. 1 facing forward and 1 facing back? I have seen this on a few "higher end" speakers.

Can we call this the "Olive Branch" video?

It doesn't NOT interact with the room. It interacts with the room differently.

I'll take the advice of an experienced thinker who's not exactly stupid over a self proclaimed or appointed expert any day.

yess indeed, open baffles fire at the wall from the behind. then all that output gets reflected from the wall, so it seems you got most of the wall reflecting it, radiating it. thats why them audiofools think its a good setup and the speakers "vanish". however, indeed open baffle does not radiate sideways. so they get less interaction from the side walls of the room, but a heck of it from the rear wall.

Isnt the back wave 180 deg out of phase, or anti phase. Anti phase is anti room node, is it not?

I appreciate this technical content. I like to surf room modes; walking helped me to feel these standing waves and have a better understanding of my room. Thank you John.

Anyone that argues no room interaction doesn't know how to place them. If placement makes all the difference then i guess room interaction is real

Open baffle speaker emit opposite polarity wave to the back. That cancels the room mode to a certain degree.

#johnheisz - how do you treat a room for open baffle speakers? Do you have video on that? Thanks!

My speakers are open 5" (modified) FR drivers on top of the boxes and a woofer (firing down onto the floor) and a bass vent on top near the 5" driver (with an acoustic surrounding bass vent, with a coaxial effect). They are holographic off the scale and the cleanest med I ever heard (sounds like aluminium ribbon drivers). But are totally just cardboard! It's that seamless silver med to treble sound that is so super even in tonality (like a ribbon med to treble driver made of aluminium and sprung tight)! That's the only speakers I can imagine it to be (other than what they really are). 😅 And the woofer makes the voice sound warm enough (with a bit of critical tweaking). I get to make it sound how I want, from lean to round and anywhere in between. It's somewhere between a lean, and a round voice sound that gives the strongest imaging! (My opinion). And along with even sounding med, dipole and point source, you get the most holographic sound possible cos it's got several factors combined to do it. Driver mods (for me) is another factor.😅

John, I subscribed about one month ago or so. Do you have a video about room treatments in the 110 Hz range and lower. There's a fellow named Dennis Foley who runs Acoustic Fields. He sells wall treatments for this range but the prices are through the roof. I have no doubt his systems work but at $30,000 for my room, which is 22' x 34' x 7.5' it had better prepare our meals and do the dishes!

Open baffle speaker systems clearly work but for 100 years audio designers have been enclosing speakers in cabinets. Now the extra materials and work involved all add to the cost, so this wasn’t done for no reason. Correctly designed speaker cabinets improve the overall efficiency of a speaker system in terms of converting electrical power into audio power. For the majority of listeners a ported cabinet system is more convenient and easier to drive for any given volume level. Cabinet systems can use smaller drivers which also is a consideration in crowded domestic situations.

I seriously always wondered why I had heard this too!!!! Im my head before I really studied audio, I had thought people liked/used open baffle speakers BECAUSE they would incorporate the "room" more-thinking that they had a room more conducive to perfect audio reproduction both in acoustics and in staging, where boxed speakers were better at 'directing' and projecting the sound.

Thanks for another great presentation. Like you, I am a fan of dipoles. I think the great advantage of open baffle speakers is the reduction of early reflections at mid-range-ish frequencies. Hence, one is hearing less of the room at these critical frequencies. Put another way, open baffle speakers alter the time interaction with the room at certain frequencies allowing one to hear more of the first arrival sound unaffected by early reflections while still allowing a degree of ambience from late reflections. Thanks!

Hi John.. Being a carpenter for over 40 years, I’ve long been admirer of your channel . Anyhow, regarding your exploits in reaching acoustic Nirvana with your speaker builds.. May I suggest that you have indeed reached a level of sound resonance, that would be completely acceptable to the majority. I believe what you should focus on now, is simply making them look sexy .. Do this and is my belief you will sell units like hotcakes.. Best wishes with your endeavours Respect KCB..👍😁🇬🇧

I am not a fan of open baffle designs, because they cannot produce sufficient deep bass due to cancellation.

If you have an open coffin speaker, do you get more room effects with or without a body?

I'm pleasantly surprised to find most of the commentary here is positive. I have been *almost* single handedly fighting against all the false claims spewed forth by the open baffle cult. Most of the wild claims center around the aspect of "superior/deep bass" from these devices. Just sticking to the topic at hand, I have made suggestions to the cult, to simply take your open baffle and move it outdoors. What happens to the bass? Pretty much gone. This suggests that open baffles are indeed MUCH MORE room dependent than their mono-pole counterparts. Simple as that. I've got plenty more to rant, but will leave it at this, for today.

Omnis/bipole/dipole speakers have a sound that “typical box speakers” don’t and many of us love it. I presently have wide dispersion box speakers which also gives me some of that sound. Live music (indoors) has more sidewall interaction that you get from most box speakers.

Most open baffle speakers I've seen use two enormous woofers & a tweeter, I'm not sure why? So your design using a midrange driver is possibly unique. Of course, a midrange driver on a wide baffle will not be a dipole. The driver front to back distance around the edges of the baffle will induce weak comb filtering instead. Keep up the good work!

All the open baffle speakers I have ever heard were fatiguing. What type of experience is the listener looking for? For me, it's 15 rows back, dead center at Carnegie Hall.

I actually tried it out by measurement. The rumors that the neighbours hear less sound when you use a dipole simple is wrong, it is identical. I had two speakers, one a dipole, one a ported box. I placed both of them at the exact same position (one at a time) and adjusted the volume of some sine test tones until it had the same "volume" at my listening position (in direct line of the speaker), measured with a microfone and the app "Spectroid" (shows volume per frequency and time). I measured the volume in the room below and noticed, that both speakers produced exactly the same "volume" in the room below. By the way, both speakers were placed on a pillow to remove mechanical coupling to the ground. Frequency was measured at a room mode and at no room mode, no difference. Thus, when adjusting power to gain the same volume, both open baffle and normal speakers were idential in their radiated power. That's why I decided not to build an open baffle speaker.

Imho the advantage of open baffle is prevent box coloration you can hear through the cone of the speaker , that's why I old German speakers they isolated the chassis with tissue ...and filled lots of damping

My 1959 house is a speaker box.

Your room is the box speaker simple as that

Drop a pebble in a rectangular container of water and see what happens. Where the pebble is dropped determines which walls of the box gets the largest amounts of water sloshed against it and how it dissipates in that fluid container. The waves will start propagating in uniform bands until the nearest wall is encountered and then the wave energy takes on the aberrations due to the container shape. The back wave of speaker in a box enclosure reaches that "wall" limitation and is reflected back into the driver cone surface causing wave cancellations/standing waves to occur much sooner and with more intensity than if they are allowed to spread into a much larger space (e.g. - portion of the listening room) into which the back wave of a dipole speaker gets its first reflections. This may partially explain why open baffle speakers sound more "natural" or akin to the original performance sounds.

I wonder if there's a more pronounced dipole cancellation in time-windowed measurements. Maybe there's a perceptibly different ratio of direct sound+early reflections vs late reflections with open baffles as compared to boxed speakers.

I knew of a girl in Nashville who was talked into getting a digital piano that she could carry around to venues. To afford it, she had to sell her old upright grand. After setting up the digital piano in her apartment studio and playing it, she realized she'd made the worst decision of her life, and lost her creativity for many months. Is there a good speaker design that would not have affected her so negatively? Electronics have gotten very good at pushing a sound into one end of a wire. Getting it out of the other end is still very tricky.

Good video, thank you for an intelligent and fair comment on the Open Baffle speakers theoretical expectation and real room interaction. You are so right, it seems there is still a grave misunderstanding regarding the existence in the room of two very different sound behaviors, almost like having two rooms, as someone said: at low frequencies the room modes are alike static pools of intense bass alternating with nulls that change configuration with frequency and are related directly to room dimensions; not much to ameliorate here, except to move out and get an even larger space to lower thus the frequency where the room mode issue manifests. Above the room modes the name of the game is : propagating sound waves, reflection, absorption, deflection, interference, cancelation, resonance and reverberation. One would measure sound, above the room modes, all around a dipole only outside an anechoic chamber and is obviously due to reflections, and not because the transducer-baffle system acoustic propagation model is lacking, God forbid ! In my experience the Open Baffle room interaction is more benign, in most cases, than boxed speakers. I use no room treatment myself and I agree with the late Siegfried Linkwitz opinion that a normally furnished, moderate lively room, is quite conducive to music listening. Regarding the alternative, one note that a dipole doesn't push as hard the driver for the same loudness level, nor hinder (pressurization) the driver membrane motion the way a box speaker does. More so, eliminating the passive crossover is another step up in resolution and linearity and offer Room correction with most DSP solutions, or one could use parametric equalizers to improve sound reproduction if analog crossovers are preferred. Thus, the sound of the Open Baffle speakers, when properly executed, remains relaxed, resolved and organic.

It might be that the firing out of the back, and then from the wall to your ears, almost in phase with the front firing is not as bad as the firing at 30, 60 and 90 degrees. With open baffles and cardiod speakers people try cancel that effect.

There are a lot of "truths" in hifi that needs to be challenged. People can't see the difference on objectivity and subjectivity. We all have a preference on what we like. Some are very sensitive to distortion in the treble others want a little more body in the lower midrange. Then is our listening rooms different from each other so different spekers perform in them. There are a few people that can't get over that you don't like the same sound as them. These people are annoying and vocal and is one of the reasons I don't hang out in hifi forums any more.

I remember when i first got Magnepans, years ago. After everything id read on forums i fully expected to hear next to nothing when i stood at their sides.

You are an engineer mind person, John. You were probably born that way. So was I. Well done.

Please look up "no baffle" dipoles. They sound much better because these are closer to an ideal dipole 8 dispersion. Essentially a no baffle speaker is one where drivers are bare and used for frequencies below the dipole peak.

An interesting experiment would be to build a box with drivers facing forwards and backwards and take measurements at various angles with them wired as both a dipole and a bipole.

The biggest thing I often hear about open baffle is they won't handle as much power.

the signals are also out of time when yoy stand in front of the speaker having diffrent affect on diffrent frequencys😊

Your experience you're sharing is of high value , nothing is better then concrete real life testing ....thanks a lot😊

I’m even less of an expert on sound than you are, John, but (or so?) what you’re saying makes perfect sense.

This means planar or electrostatic speakers are the only ones able to radiate front and back without any variation?

I don't think open baffle is good for the average person that doesn't have a treated room and cabinets reinforce the output

"You're getting output from the back of the speaker." That strikes me as a common sense reason for more room interaction.

I’m so glad I discovered this channel. I need this knowledge so bad.

9:11 Hi. I’m an inventor who hasn’t delved into speaker building, but I have pondered it. I am drawn to back-to-back speakers of reversed polarity (so they wiggle in phase with each other backwardsly). One can put tubes of varying lengths between, and it provides valuable space between the planes of the forward and backward drivers, allowing for curved interfaces and, well….

I wonder if one could design a driver that has a cone at both ends with the voice coil and magnet in the middle, instead of a cone at one end and a magnet + basket at the other end

Very well put! Every speaker regardless has room modes and best placement. Just different more or less based on the design.

Yes. one of the points is...The typical room in a house is "too small" to use a "boxed" bass enclosure. The benefit of the open baffle design for drivers producing omni-directional frequencies is they are canceled out in the fields on either side of the speaker baffle. You are correct that it then takes more bass driver to produce the same output. I welcome your challenge/discussion and will be watching the comments.

John, is your 37hz room mode front to back, or side to side? If it’s front to back, then of course it would also be excited. From personal experience I disagree about exciting room modes, the side to side ones are much diminished in my experience.

Dipol speakers can only Sound good If they stand far away from the Back wall the reason is: early reflections cause Bad Sound. Dipol speakers got much more early reflections in rooms than normal speakers. Best OB would be a OB Line Array 1.8m away from the Back wall with good damping and Diffusion and the early reflections Points (Line Array because the floor and ceiling reflections would Not be a Problem anymore) (And Most ppl prefer a closed/Vented/PR sub under 250 Hz cause they Like the Feeling of the kick of the Drums) Yes Ob subs can sound good but you will notice Something is Missing, even If it goes down to 16Hz. Sorry for my bad english.. Love your content greetings from Germany.

Modes or nodes? That is the question.

The long touted claim is, ... due to the manner in which they interact with the room, dipoles generate a higher level of direct sound and diminished amount of room sound to the listener. It's not the magnitude of the rearward energy that's important, it's the polarity is the mechanism here. Thus in dipole the energy doesn't pulse the space with a coherent pressure wave (as does a monopole). Listeners in rooms appreciate the velocity component of the propagation in addition to the pressure. We experience sound so radically different then mics capture that energy. It seems our discernment is high, yet our aural memory flawed.

Great to see some straight talkin in the audio world. Well done vid.

True. Also I find open baffle speakers a bit philosophically suspect. Imagine that your goal is to reproduce the experience of listening to an orchestra 5 to 10 meters away from you (by using loudspeakers 3 meters away from your listening chair for example). Would it make sense for the sound waves to partially change direction 180 degrees, hit the back wall, and then move towards you again out of sync with the first wave (and from a different angle) after having travelled 2 to 7 meters from the instruments they originated from? ;)

For mid and highs yes not for the bass on the other hand those mid and highs are easy to controle in a room. But If you have more in one region than before and less in the other Fc-200 it balenced out to my opinion. basstraps are way more intrusive in some one's space. Is there some one in fluid dynamics with a better anser. In the and guess its like tubes its obout flavor. I now peeps who like OB Fc-5000 others Fc-20K To me I would say less room interaction in general. And the bass feels more directional. And have you ever, in your life seen a tweeter shake the room.

Sorry, new subscriber h😂re - Have you created or tested a model where you box in the bass speaker only? I always wanted a pair of Dahlquist DQ-10s and I believe that’s what they did.

The room is fully a partner with the open baffle speaker. IMHO it should be tuned every bit as much as the speaker is...

If you can hear it then it's interacting with the room.