The REAL Reason Why Open Baffle Sounds Better Than Box Speakers

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My opinion, after thinking on it long and hard and listening to my own open baffle speakers for 2 years is that the main difference is the midrange presentation.
The open mid projects the sound back out of phase with the front output and reflects off the wall behind the speaker. It then combines (largely in phase) with the front output and changes what you'd get from the front firing driver.
So, in a boxed speaker you only get that front firing sound, while the dipole gives you that PLUS the reflected back firing output as well. That changes the character of the sound and gives open baffle its distinctive sound quality.
Is is perfectly accurate? No, obviously not, but that really doesn't matter. You either like it or you don't, and that's what's important.
Now I will say that unless you've actually tried listening to a well designed pair of open baffle speakers, you can't have an opinion either way. I think most who do start listening to OB don't go back to boxed speakers. At least not willingly - maybe their situation changed and they need to listen in closer quarters where the speakers must be too close to the front wall to realize the benefits of OB.
I used the term ethereal to describe the sound difference because it's the word that came to mind, but maybe a better way to describe the OB is to say more expansive. As in it projects a bigger sonic presentation, but retains pinpoint imaging and immersive soundstage.

I focused on the midrange driver with these conclusions in mind. The bass is omnidirectional for all speaker types, and the tweeter doesn't carry enough of the music spectrum (there's very little content above 10KHz in most music) to warrant making it rear firing as well. Whereas the mid carries the bulk of what serious listeners are looking for in a refined and engaging listening experience. My design lets the high efficiency mid play a wide range of the audio spectrum and is run through a 1st order bandpass filter to extend that coverage down into the low midrange and up into the treble.

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[IBuildIt]

READ ME!
My opinion, after thinking on it long and hard and listening to my own open baffle speakers for 2 years is that the main difference is the midrange presentation.
The open mid projects the sound back out of phase with the front output and reflects off the wall behind the speaker. It then combines (largely in phase) with the front output and changes what you'd get from the front firing driver.
So, in a boxed speaker you only get that front firing sound, while the dipole gives you that PLUS the reflected back firing output as well. That changes the character of the sound and gives open baffle its distinctive sound quality.
Is is perfectly accurate? No, obviously not, but that really doesn't matter. You either like it or you don't, and that's what's important.
Now I will say that unless you've actually tried listening to a well designed pair of open baffle speakers, you can't have an opinion either way. I think most who do start listening to OB don't go back to boxed speakers. At least not willingly - maybe their situation changed and they need to listen in closer quarters where the speakers must be too close to the front wall to realize the benefits of OB.
I used the term ethereal to describe the sound difference because it's the word that came to mind, but maybe a better way to describe the OB is to say more expansive. As in it projects a bigger sonic presentation, but retains pinpoint imaging and immersive soundstage.

I focused on the midrange driver with these conclusions in mind. The bass is omnidirectional for all speaker types, and the tweeter doesn't carry enough of the music spectrum (there's very little content above 10KHz in most music) to warrant making it rear firing as well. Whereas the mid carries the bulk of what serious listeners are looking for in a refined and engaging listening experience. My design lets the high efficiency mid play a wide range of the audio spectrum and is run through a 1st order bandpass filter to extend that coverage down into the low midrange and up into the treble.

[IBuildItHome]

“Great minds discuss ideas. Average minds discuss events. Small minds discuss people.”
― Henry Thomas Buckle

[richardtheweaver]

I used to have Bose 901s. Trapezoidal, point to back, four drivers on each back plane and one in front. Lots of similar theories are used in OB, such as external tuning:

901s were designed so their rear point is 18” in front of the wall. If you build OB you should fiddle with angles and distances, along with wall shapes: a corner or shallow convex “v” might be fun.

Bose said that multiple speakers can’t resonate at the same frequency. I don’t know how much of that is physics and how much is engineering.

I like the ring-of-midranges look. Perhaps add a short tube to the back of each driver and put two speakers back to back. Six double-coned speakers will ease and broaden. Twin baffles allow for great off axis listening.
All together, you’ll have all sorts of levers to adjust to get the sound right.

I would keep the subwoofer separate. The above setup will lower the optimal crossover frequency.

The baffle can be circular, but scalloping can direct and adjust response while giving the speaker a more flower-like look.

Thumbs up

[paulhirst]

I really enjoy a large soundstage and good imaging. For me, my OB speakers excel even in a small room.

[Newrecordday]

This is a great breakdown. Thanks John!

[hitnorcal]

I made open baffle 15's because of your videos. They are amazing, especially with a low watt amp and sub woofer. Now I am not taking your advice and making a pair of 8 in transmission lines speakers with 3 speakers to swap out a test. Building the box off the longest necessary line and will add fill for the shorter lines as needed. I want to a 3 way open baffle but I don't have the tech know how to make the cross over so I will have to wait for yours.

[mikebeacom]

Thanks for the di-pole discussion. It reminded me of the properties of a bi-directional mic, and gave me a better way of thinking about open baffle speakers

[johnorourke]

I’m really enjoying your videos. I experimented with open baffles about 30 years ago after reading about them in a British magazine. I got some great results even using some pretty modest parts. You have fired up my enthusiasm and I might just build some again.

[StarvisionGraphics]

Interesting John! I will play more open baffle examples now. You have my audiophile ears piqued!!

[firecloud]

When a musical instrument is being played in a room, you hear the sound from the instrument as well as the sound of the instrument bouncing off the back wall. An open baffle midrange does basically the same thing.

[Aviator]

My bedroom has a large walk-in closet, and on the other side of the closet is my listening room. So I just mounted the drivers on the wall of the closet. Is this setup a box speaker or an open baffle speaker? They do sound very good though.

Getting the reflection from the back wall and mixing it up with the sound wave from the front is tricky. On certain frequencies, the waves cancel and that depends on the distance how far the speakers are from the back wall. The further away, the less the cancelation since the energy of waves reduces with the square of the distance. So the closer the listener is to the speakers, the less the cancelation.

[daltonknox]

I have been using Magnepans for over 40 years. I love their combination of huge sound stage and detail which as you suggest is best heard in dipoles.

[acreguy]

Great video, John! Thanks. I had a conversation thru email with Jerry McNutt at Eminence a few years back. I was wanting to redesign my center channel and he suggested moving to open baffle speakers. He implied that some Eminence drivers were excellent for that idea but didn't go into specifics.

Also, you mentioned that your mids sounded fuller or more real. You had trouble describing the sound, for which I don't blame you. My dad often worked sound in large theaters in the 60s and commented that the Altec speakers did not provide a *loud* sound but a *large* sound. Perhaps that helps you in your thinking about the mids.

About 20 years ago, the late Bill Woods once told me to add 2 feet of baffle to either side of my Altec Valencia boxes. I never did but he was "sort of" toying with an open baffle concept. He was so far ahead of his time in many ways. Sad that he's gone. Anyway, thanks again!!

[jfritzy]

Tried Open Baffle Subwoofer on a whim. Had a couple subwoofer drivers from an Infinity system. Put them in a couple small open back boxes. Not expecting much was shocked by the difference from my large sealed box subwoofer. Actual bass notes could be heard instead of a mostly chest thumping monotone boom-boom-boom. Next built a Ripole subwoofer. Surprised again by how much more bass tone and texture is revealed. Never go back to a sealed sub.

Considered trying to build my own open baffle speakers, but your design is definitely of interest. Suspect hearing open baffle full range speakers would ruin me.

[johngutmanis]

Hi John, I would buy your plans for your open baffle speakers. I have owned Magnepan.7i, 1.7i, and now have LRS, which I am selling because I never listen to them because of the Klipsch La Scala’s in the room. I am a wood builder as opposed to being a wood worker. To me a wood worker is someone who loves to work with wood, a wood builder, like myself, builds cabinets, boxes, doors, ect. because of the economics and enjoyment of DIY but not obsessed in perfection. Any way, I enjoy your channel and I would buy the plans. I think a cone driver is more effective than a panel in moving air!

[DaleCrommie]

I took a chance on the Lii Audio 15 inch full range. Now that I have it in a 1.5 inch Baltic Birch baffle, oh my. Open baffle is open, I get a completely open soundstage, where the music is placed so well. This is what I have been looking for for a few years. Open baffle is really nice.😄

[stackoverflow]

John, more than halfway into the video, you're reminding me of Bose 901s, not accurate but ethereal provided you use the EQ and an amp that can withstand sustained 15db to 25db EQ boost in treble and presence.

[timboz]

In my experience OB flavours everything you listen to, with the sound of your room, to a greater extent than closed speakers do. So they shift a colouration of a box to the colouration of your room. Are they cheaper and easier to make, ship and sell?

[andrewau]

I've got a set of mirage om12's, listening to you explain how the sound is more full I can relate, the sound is beautiful compared to a normal boxed speaker

[trevorbartram]

Hi John, I have new bookshelf speakers located in a new position in my listening room. The room is carpeted but untreated however, wall & ceiling cavities are filled with fiberglass insulation. It took much experimentation, using acoustic bass recordings, to position the speakers to eliminate several bass room modes. I then added a subwoofer between the speakers & dialed it in, it sounds good. My problem is the sitting position doesn't offer the best sound available in the room & I don't really have an easy way of changing it. The best sound occurs further away from the speakers & standing up! My point is ideally both speaker & listening positions need to be optimized for best sound.