Open Baffle speakers

[Adi777]

Hi. For some time now I have been reading a lot about OB loudspeakers, i.e. Open Baffles. Are they really special, as their owners claim?
I often hear the description of the incredible naturalness of the sound from such loudspeakers. Is it really so? If so, could it be related to "no housing"?
Any of you listened to such constructions? If so, what impression did they make on you?
What potential disadvantages can Open Baffle have?
Regards

 

[zvukofor]

Hi.
Indeed, they are in their own class for their qualities.

Incredible "naturalness" is just a trick with our perception. Due to the fact that open baffle speakers radiate in figure-8 pattern, filling room with a sound, our brain can ignore room acoustics/reflections much easier, just as it does with natural acoustic sources. Plus, again due to figure-8 open baffles has less problems with bass - room modes are less excited - less boomy sound... and no enclosure resonanses really helps too.
So, it is not a mystery, but pure physics/acoustics.

Disadvantages: much less effective system, need baffle step correction to flatten LF range and correction for acoustic short circuit effects — lot of technical problems to solve, but in reality almost as much as for closed/vented boxes. Also, can't put'em close to walls...

For more technical explanations and research please read materials by Siegfried Linkwitz, who dedicated a lot of his life to high fidelity and natural-sounding speaker systems.

Linkwitz Lab - Loudspeaker Design

Design and consultation in electro-acoustics. Fundamental concepts of sound reproduction in rooms. Detailed design information for DIY construction of a subwoofer and an open-baffle speaker with exceptional fidelity. Dipole loudspeaker design for true to the original sound reproduction with...

www.linkwitzlab.com

I was really impressed by all effects of open baffles almost 10 years ago, then built my own speakers, really love'em and still use it daily, even for my job - music production / sound engineering. Open baffles are the first speakers i've heard that reproduced double bass as it should sound.

 

[Adi777]

Disadvantages: much less effective system, need baffle step correction to flatten LF range and correction for acoustic short circuit effects — lot of technical problems to solve, but in reality almost as much as for closed/vented boxes. Also, can't put'em close to walls...

Can such loudspeakers be successfully integrated with subwoofers? If yes, should the subwoofers also be Open Baffle or not necessarily?

 

[zvukofor]

Can such loudspeakers be successfully integrated with subwoofers? If yes, should the subwoofers also be Open Baffle or not necessarily?

Definitely, if main units do not work in full range.
IMO open baffle subwoofers are much better than boxes, because of radiation pattern. Less modes excited, as i've told before, so - much more defined bass.

 

[DVDdoug]

Can such loudspeakers be successfully integrated with subwoofers? If yes, should the subwoofers also be Open Baffle or not necessarily?

Generally you need an enclosure for deep bass.

Speaker design is always a trade-off...

The soundwaves from the back of the speaker are out-of-phase with the front, so they tend to cancel, especially at low-frequencies which have longer wavelengths.

I've seen pictures of multiple large subwoofers in an open baffle configuration but most subs (and most speakers) have a cabinet.

A ported cabinet is normally "tuned" to extend the low frequency cutoff lower than what you'd get with the same sealed box (or an open baffle). But there are trade-offs and a sealed box normally rolls-off more-slowly so they can sometimes go lower.

I've never heard of a studio monitor that wasn't sealed or in a ported cabinet. You probably won't find any open baffles in your local audio-video store either.

 

[fpitas]

To a noob, all these choices may be infinitely baffling.

/I'll let myself out.

 

[thegeton]

Excuse me for being off topic, but this type of thread is why I come to ASR: candor, straight forward responses, fact based information, and respect. Fabulous.

 

[Adi777]

You probably won't find any open baffles in your local audio-video store either.

There aren't many of them, but the fact that they are seems interesting. For example:

ANTEROS-9 OPEN BAFFLE Loudspeaker system - Thivanlabs

thivanlabs.com

 

[Waxx]

Generally you need an enclosure for deep bass.

Speaker design is always a trade-off...

The soundwaves from the back of the speaker are out-of-phase with the front, so they tend to cancel, especially at low-frequencies which have longer wavelengths.

I've seen pictures of multiple large subwoofers in an open baffle configuration but most subs (and most speakers) have a cabinet.

A ported cabinet is normally "tuned" to extend the low frequency cutoff lower than what you'd get with the same sealed box (or an open baffle). But there are trade-offs and a sealed box normally rolls-off more-slowly so they can sometimes go lower.

I've never heard of a studio monitor that wasn't sealed or in a ported cabinet. You probably won't find any open baffles in your local audio-video store either.

Not really true, there are OB like systems like a Ripole or a slot loaded OB subwoofer that give deep bass without a real cabinet. But they are hard to tune right and need higher order crossovers so most use sealed subs and dsp to get it more or less right.

 

[hex168]

Whether a dipole speaker needs a dipole sub is...complicated, and whether one or the other is better depends on the modes in your room. A monopole sub can "pressurize a room" and take advantage of room gain.
See:

roomgain

roomgain2A

Dipole_modesA

 

[Waxx]

Whether a dipole speaker needs a dipole sub is...complicated, and whether one or the other is better depends on the modes in your room. A monopole sub can "pressurize a room" and take advantage of room gain.
See:

roomgain

roomgain2A

Dipole_modesA

That is just a thing many with OB's try to avoid. And i have to say it sounds good for the right kind of music (more acoustic music).

But i'm a dubhead also and I need a lot of pressure on the bass. And so do many who listen to electric or electronic music. So it's not everybody's cup of tea for sure. I could use an OB sub, but not as the only option, only for some kinds of music i listen to (jazz, classical, ...)

 

[suttondesign]

I discussed this yesterday:

The Physics of 3-D Soundstage

A member @restorer-john made the recording linked below in his backyard with a portable recorder. I hear left right, front back, and higher lower. I think the recording which retains actual spatial information is key to the image. Fancy electronics that try to mimic real spatial information...

www.audiosciencereview.com

 

[ctrl]

What potential disadvantages can Open Baffle have?

Just posted a thread on possible pitfalls with certain OB design - "Open baffle speaker pitfalls". Maybe this will help you a bit.

 

[kemmler3D]

I would say subjectively OB speakers are less susceptible to being "wrecked" by a bad room. I still remember hearing some martin logan electrostatic speakers in the suites at an audio show. Compared to all the box speakers (which suffered badly from the not-so-good sounding rooms) they sounded pretty clear and natural. I think because the sound is scattered more evenly and you get a smooth but highly indirect response in the room, you ironically hear more of the speaker and less of the room in many cases. When the speaker is any good, this tends to be a good thing.

I think box speakers can beat OB speakers on many dimensions, but it's harder for them to overcome directivity and room issues, where OB speakers kinda cut the gordian knot and sidestep a lot of the design challenges of box speakers.

The soundstage you get is not the same, but many people prefer it.

 

[Adi777]

I think box speakers can beat OB speakers on many dimensions,

Can you write something more about this?

 

[Adi777]

That is just a thing many with OB's try to avoid. And i have to say it sounds good for the right kind of music (more acoustic music).

But i'm a dubhead also and I need a lot of pressure on the bass. And so do many who listen to electric or electronic music. So it's not everybody's cup of tea for sure. I could use an OB sub, but not as the only option, only for some kinds of music i listen to (jazz, classical, ...)

Why acoustic music, or jazz and classic, but not electronic for example?
What if the OB speakers are very large, with a couple, for example 2-4 18 inch woofers on one side for the lowest bass plus 2-4 12 inch for the upper bass?

 

[roog]

I don't have the facility to test speakers, but I did build a large stereo pair of 3 way open baffle speakers, comprising: 2 x 15" bass + 1 x 8" mid + 1 x 27mm treble in each speaker. I used DSP active crossovers and six way power amp driving each driver separately.

I was aware of the 'comb' filtering effect of the modest baffle, IMO anything short of 'too big' is too small to be useful!

I did not think much of the sound in a normal room environment, lack of bass, as anticipated, but also lack of sound stage (stereo effect), they had a mono like presentation. I had them in store in a small box room and tried them in there for fun and found that in a near field, (1 metre away arrangement), these huge speakers improved the stereo effect! I assume that the contributions from the back of the baffle became less important under these circumstances.

It would be interesting to see a proper test of this type of speaker as mathematically and to my ears they are a flawed concept, unless you are able to accommodate a very large baffle to prevent cancellation lower down the registers.

 

[Adi777]

very large baffle

Yes, this is very interesting to me. How such a huge OB can sound with professional acoustics and perfectly placed in the room.

 

[Gorgonzola]

Hi. For some time now I have been reading a lot about OB loudspeakers, i.e. Open Baffles. Are they really special, as their owners claim?
I often hear the description of the incredible naturalness of the sound from such loudspeakers. Is it really so? If so, could it be related to "no housing"?
Any of you listened to such constructions? If so, what impression did they make on you?
What potential disadvantages can Open Baffle have?
Regards

Pardon me but these are my impressions only, I'm not an acoustic or speaker design expert.

I ran Magneplanar "panel" speakers for about 15 years and enjoyed them very much. I used a vented box subwoofer with my Magneplanars with no problems of integration. Given that lower frequencies, (below, say, 80 Hz), are effectively omni-directional, I personally have never been persuaded of any special merit to OB bass. That is, OB bass requires more complex design in order to chase a problem that doesn't really exist.

As you probably know, the Magneplanars are flat panel, dipole speakers that produce the discussed "figure 8" dispersion pattern. At lower frequencies, (which have longer wave lengths), the out-of-phase front & rear waves tend to cancel out, a tendency that becomes complete at some low frequency.

OB designs with pretentions to deeper bass aim to cancel the cancellation phenomenon by employing very wide front baffles and/or side extensions that are wider than the wave lengths are long. (Pardon me, this explanation is a bit simplistic but, I think, fundamentally valid.) The Magneplanar speakers do not have these extra extensions.

 

[kongwee]

I used to have a Martin Logan, it is easier to make the speaker "disappear". I did audit the maggie too. I believe OB could do that if you have room to play around. You could hear the box resonate on conventional loudspeaker if you own one. Of course, there are box speaker out here that has lower box resonance but at high price. ML nowadays are $15k. Add a few thousand you can get very good box speaker that don't ring that much.