Open Baffle vs Box

An open baffle would cause the back wave to distort the front wave. Thats the whole point of a box to stop that. If you enjoy distortion then thats your choice. 

Totally wrong.   The back wave can cancel some response of the front wave (less output) if the baffle is narrow and the frequencies are low.  To get low bass you need a big baffle, large woofs or servo woofs, 

Distort?  No way.  Open baffle speakers generally have a more spacious sound and less box sound.  Done right, they are incredible.  Check out GR Research and Spatial speakers....they are killer.

I've had both Vandy 2CE SigIIs and Spatial M4 Triode Masters in the same room and system. Other than low bass extension, it's really no contest, the Spatials are all-around superior, and by a wide margin. In fact, I owned the M4 TMs prior to the 2CEs and going to the latter was like my ears had suddenly accumulated a bunch of wax, everything sounded dull and veiled. 

Yeah, don't get the distortion thing at all. Great speakers, those Spatials... I sent you a rather lengthy PM; any other questions, feel free. I'm on Long Island if you want a listen.

Kenjit: " An open baffle would cause the back wave to distort the front wave."

The backwave would cancel the front wave at frequencies where the wavelengths are long relative to the baffle dimensions. This cancellation results in a rolloff of 6 dB per octave above the driver’s free-air resonant frequency, accelerating to about 18 dB per octave below the driver’s free-air resonant frequency. This rolloff can be corrected by EQ up to the displacement limits of the drivers, and then distortion would set in. But the backwave in and of itself does not distort the frontwave, any more than the sound radiated backwards from an upright bass distorts the sound radiated frontwards.

"That’s the whole point of a box to stop that."

The point of a box is to stop cancellation at long wavelengths, so I think we agree on what the box does to some extent.

"If you enjoy distortion then that’s your choice."

This statement is based on a false premise, which can be paraphrased as "the backwave of an open baffle speaker distorts the front wave." Therefore the implied conclusion, namely that someone who enjoys open baffle speakers is enjoying distortion, is also false.

And in my opinion the insult aimed at those who like open baffle speakers is an unnecessary display of aggression.

Duke

@helomech could you add some more of your experience in how bass behavior is different with the Spatials? I’m on the fence but since I listen to a lot of bass heavy music I’m trying to create a mental picture of how OB bass differs.

Thanks :-)

You didn't ask me specifically, but to me, OB bass surrounds you rather than punches you. This is not a quality judgement, they can both be great. In my case, where my room is less than ideal, the Spatial OB sound works better than box; though it feels like less bass, it sounds like better bass.

@james_edward 


thank you. I appreciate your input. It was
Described to me before that you ”get the punch but not the rumble”. do you agree with that description?

Above 100 Hz open baffle speakers can be great given the right drivers. It is much easier to build a plate that does not add colorations than a box.
All of my favorite speakers, the ones that I would own are boxless. Under 100 Hz is a different story. The problem is that building a SOTA subwoofer is an expensive and difficult task and the end result will be a device that is very heavy and expensive to ship. Most manufacturers cut corners resulting in flaws that for those of us who have experienced the best bass find intolerable. I believe those of us with DIY capability can actually do a better job than most manufacturers but in forms that could not be competitively priced. 

I own several dipole speakers one pair being the Spatial Audio M3 Turbo S.. I think “punch without the rumble” is a decent way to describe some of what good open baffles do. They remind me of my Maggie’s in some ways but with significantly more punch. 
NO RUMBLE... 

@birdfan
Thanks.  that what my dilemma is with the Spatials. I live in an apartment so subs are not advisable but it seems to be the only way when dealing with music that has lots going on below say 50hz.

If your room is smalliish... you won’t need subs unless you are listening to a lot of EDM( which at times I do and I add stereo subs)... additionally the bass you do have is very fast .. no overhang, no bloated farts, no boom.. just clean fast right low end. Admittedly open baffles need a lot of surface area to get really low, but I love my Spatials even without subs... imaging is open full of air and well defined. You have to make sure you have the space to pull them away from the walls at least 2 feet.. I was disappointed I didn’t get to hear Claytons new sapphires model this year at Rocky Mountain audio fest.. they look nice... AND when your neighbors are gone they can literally shake the house off the foundation .. it’s one of the speakers I own I feel do every genre of music justice. Jazz, big and small classical, rock, edm, acoustic guitar, everything... fantastic imaging...

@birdfan
Thanks. I don’t do hardly any EDM but rather lots of punk, reggae, 80’s/90’s alternative, hip hop with a sprinkling of metal and some deep sub bass exploration.

@helomech could you add some more of your experience in how bass behavior is different with the Spatials? I’m on the fence but since I listen to a lot of bass heavy music I’m trying to create a mental picture of how OB bass differs.

The bass of the M4s is articulate. It's not the fastest I've experienced but neither is it slow. The Vandys have lower extension by at least half an octave but that's to be expected. I did experience a small amount of bass-boom with the M4s after the woofers began to loosen up. However, I attribute that to my unusual room that has thick concrete walls on 3 sides and a concrete floor. It's the most challenging room I've ever dealt with in terms of bass, so I wouldn't fault the speakers.

I probably could have resolved the issue with different placement but I wasn't willing to compromise on that at the time. 

Spatial grants a 60-day in-home trial, so there's really nothing to risk aside from return shipping cost, which in my case was quite reasonable being that I'm only three states away. Even though I didn't keep them, I still believe they're one of the best (if not THE best) speaker values out there. Most speakers that sound their equal in absolute terms cost at least twice the price. 

@helomech Thanks!

audiosaurusrex


I think there is one more aspect of the new Spatial M3 that you will only know for sure by trying them at home....that is the saphire (ceramic) mid/tweet driver.

(from the Spatial Audio page on Audio Circle..." new wideband, large dome unit which operates from 500Hz to 40kHz"....and...." the 2 woofers operate in parallel below 100Hz, so the impedance drops to 4 Ohms.... Minimum is about 3 Ohms over a very narrow range)."    So, the way I read this....both 15" woofers operate together below 100hz...one 15" woofer covers 100-500hz and then the ceramic driver covers the rest.

I heard the original M3 non turbo units at Spatial in a somewhat small rectangular corner or their speaker assembly area in Salt Lake...and they sounded darn good...not a hint of brightness...so I'm guessing these sound even better....and with the 60 day home trial, the only thing you risk is a couple hundred bucks of return shipping....

gochurchgo, what you get is a confused mess lacking in both punch and rumble. As the wavelength of the reproduced sound gets longer than the driver is wide the sound gets increasingly more omni directional. The wavelength of 100 Hz is around 10 feet, far longer than a 12 or 15" driver 
is wide. The rear wave of a woofer is 180 degrees out of phase with the front wave and both are omni directional. They cancel each other. Stand directly to the side of an open baffle woofer and there will be no bass. Now depending on the distance to the front wall the rear wave will bounce off the wall and come back at you at a different phase angle and things get more confused. Contrary to popular belief increasing the size of the baffle board does not help at all. Low frequency sound is very powerful and can travel long distances in air. Ask anyone who has been within 10 miles of a plane breaking the sound barrier. 
For all the difficulty in building a proper bass enclosure the results are well worth it, even more so given modern high power amplifiers and digital bass management. So why wouldn't this work with dipole sub woofers? Well, when two sound waves 180 degrees out of phase sum you get zero. More of zero is still zero.

Very interesting posts from everyone. Makes me think that the people who love open baffle designs are much like the Vandys fans of which I’ve been for many years. Either lovem or not so much. Speaking with Clayton he believes that open baffle designs will ultimately dominate the market at some point. My room is 14x16x8 old style cape with hardwood floors pretty open area rug and no window treatments. Using a Krell Digital Vanguard to drive them. I liked that the Vandys have a wide open soundstage and sound pretty good even from the next room. So do the Spatial’s have a narrower sweet spot? And is placement as critical as with the Vandersteens?

An open baffle would cause the back wave to distort the front wave. Thats the whole point of a box to stop that. If you enjoy distortion then thats your choice.

 Another belch, from the Dunning-Kruger Poster-Boy!
.

@elizabeth 


agreed and unfortunately I only know what I read. I, too am an apartment dweller and might be forever which is where Spatials we’re first recommended to me. I’ve put it out there on the Spatial forum that I’d like to hear them from a local and in 30 minutes I’d know what I want to know about them. Seems there are no locals who have them who also post there.

i keep scrubbing them off my list but they keep being re-added. On paper they check all the boxes (with bass being the unknown quantity). If I could just add subs then I’d go that route.

I went from Maggies, to Emerald Physics(the original designer, Clayton Shaw, owns Spatial), for tube-driven main speakers, in my actively bi-amped system. Needed the added efficiency. Same openness/spatial realism and instrument size/excellent imaging, as my various pairs of planars(Acoustat and Magnepan fan, since 1981).   I could easily get along, without my SS-powered woofers, running my Emerald Physics/tube monoblocks full-range.

btw: Emerald Physics also offers an electronic EQ, they call their, ’Bass Optimization Module’(BOM), which allows you to dial in the Bass, to suit your room/speakers/tastes. (https://www.emeraldphysics.com/products/bom)

I am a Spatial X3 owner and I must say, these are the real deal. No apologies offered for ANY genre of music. They do it all equally well.

Oz

agreed and unfortunately I only know what I read. I, too am an apartment dweller and might be forever which is where Spatials we’re first recommended to me. I’ve put it out there on the Spatial forum that I’d like to hear them from a local and in 30 minutes I’d know what I want to know about them. Seems there are no locals who have them who also post there.

i keep scrubbing them off my list but they keep being re-added. On paper they check all the boxes (with bass being the unknown quantity). If I could just add subs then I’d go that route.

I recently acquired a pair of Maggie .7s and believe they might better fit your needs in an apartment, especially if max SPL is a concern. Unlike the other Maggies I've heard (1.7 & 3.7), the .7s produce real midbass punch, and seem a lot less current hungry. I drive mine with a 160 watt/ch/4 ohms amp. The VU meters rarely peg above 50 watts - that's in a room of about 1365' cubed. 

The Spatial M4s liked to be played loud and I often found myself nudging the volume knob until I was pushing 95db peaks. It's not like they sound anemic at low volume like many speakers; it's just that they urge you to keep cranking, probably because they have super-high power handling and are capable of loading a small auditorium. Not once did they reach a distorted playback level before my ears gave up first. The Sapphires have different drivers of course, so could have completely different behavior for all I know. 

With the .7s, I find the 70-75db range sufficient for most listening. That wasn't the case with 1.7s which wanted to play at 80db+.

I would take the M4s over 1.7s and 3.7s any day, but the .7s are a different animal and I consider them competitive with the entry-level Spatials. 

If you have the space (ie they can be very large) and you don't mind the looks (look ma, no box!) then open baffles are certainly worth a try for the sheer life-like freedom in sound that they offer. Much like open backed v closed back headphones.

What boxes do to the signal isn't pretty whichever way you look at it, you can always hear it, especially in the mids. No such thing as a silent loudspeaker cabinet, though some, like the Harbeth range do try awfully hard.

There are quite a few interesting designs where the midrange unit is backless combined with the bass driver in a box. For me it's telling that Siegfried Linkwitz eventually settled for an open baffle / box combination for his ultimate design. 

Sadly the complexities of getting an open baffle/dipole design to integrate well are no less than those for box speakers.

OB Bass is much more pitch accurate and defined than box bass. The only other bass design that comes close is a true horn loaded design.

Oz

First, my room is volumetrically large with no discernible backwall reinforcement. My box speaker experience includes; Genesis Vs, Usher 6371s, Nearfield Pipedream Accoustics (sans sub woofers), Swan Diva 6s. For OBs; Accoustat 2+2s (2 close friends had custom frame Accoustat 10s, but in very large rooms, both reinforced with dual subs), Magnepan 3.5Rs with and without subs, and currently Emerald Physics KC IIs (with and without subs), and a pair of EP 2.8s on their way (dual 15" + 12" coax drivers).


I have a EP BOM, but the SVS Ultra and Plus subs just don’t marry well without an expensive 3 way active XO; I blew through 4 cheap active XOs, but when they worked, well, there was some magic there.


Unless you are buying huge planar speakers, bass is not likely to have the impact of cone drivers in OB speakers

What I recently discovered was of the many amps I had in the last 4+ years, RIc Shultz’s EVS 1200 has the mid-bass and bass authority none of the others had. I have owned the KCIIs for 3+ years but never heard them as cohesive top to bottom as they sound with 100+ hours on the EVS 1200. This amp could be magic on Maggies as well. A few maggie owners have chimed in that the new IcePower class D is giving them the best sound they've had

I have just recently moved from a full Vandersteen setup consisting of 3a signatures and a stereo pair of 2Wq subs with the $1000. M5 HPB high pass filters to Emerald Physics EP 2.7’s. (As mentioned Emerald Physics was Clayton Shaw’s company before leaving to start Spatial) And I can tell you there is no going back for me. These EP’s are the best speakers I have ever heard. They have the open spacious presentation of Maggi’s with the dynamic power and efficiency of pro audio loudspeakers. They load the room much like Maggi’s. And the bass is to die for. It is so coherent with the rest of the sound because the same drivers reproduce the upper and lower bass. It really is "better than subwoofer bass" as one pro reviewer stated. I know what conventional wisdom says about OB bass but that is not the case with these modern open baffle designs. In fact when I first got them I tried them with the 2Wq subs then removed the subs and the bass output actually increased! The EP 2.7’s are rated at 97 db efficient (without DSP and 100 db with) and the subs just could not quite keep up. I was amazed! Now in ultimate terms the subs go lower, down to 19 hz maybe lower and the EP2.7’s are rated to 38 hz without DSP which is how I am running them now. (But they will go to 20 hz with the EP Bass Optimization Module B.O.M or DSP) Most music does not have much content going that deep so I have not missed it at all. The bass that is there is to die for! No box sound at all. I found that to be one of the biggest surprises. You don’t how much sound boxes make until it’s gone.

I agree that the Vandy’s sound a bit flat and dull by comparison. The EP’s are so dynamic, engaging and just plain fun to listen to, much closer to live music. They do invite you to turn it up, even at low level nighttime listening, they just grab your attention, it’s hard not pay attention to the music.


They do require being pulled out from the wall behind them however. Mine are almost 5 feet to the front of the baffle. Fantastic imaging due to the coax 12 inch midbass and compression midtweeter. Crossover point is at 900hz well below the critical midrange region. So smooth and the tone just is addicting, RPaT it’s all there! I really can’t say enough good things about them.

As they relate to the Spatial’s? They are the same basic design so should have similar sound. The EP 2.7’s have two 15" woofers and the 12" midbass coax tweeter. (Mine have been upgraded to the new tweeter from the current top of the line EP2.8’s and the crossover was tweeked to match)

The concept as I understand it regarding bass cancellation is to just overwhelm it with sheer displacement. That’s why the multiple 12 and 15 inch woofers. All I know is that it works!

There are several Spatial and EP speakers for sale here on AudioGon and elsewhere. Take advantage of the discount, give em a try.
Good luck.

@sonicjoy Thanks for the very informative post. I really was looking for a former Vandy owner to chime in. While there have been no formal reviews of the M3 Sapphire with a 60 day in home trial I have nothing to lose. I was debating stepping up to the X3s but I should really control myself. With Clayton’s knowledge and continued passion to improve I’m sure they will be killer speakers.
It was actually Clayton that suggested I post this question and the answers ranged the gamut and I appreciate everyone jumping in. As I have said I always find this forum extremely helpful!!

Glad to help! I have a feeling you will be pleasantly surprised.
Cheers.

It’s cool you are talking to Clayton and getting advice from the designer. I am working with Mark Shifter he is one of the other designers of Emerald Physics speakers amps and DSP units. (currently working on their next gen amps) I actually bought my EP2.7’s from him and he is the one who upgraded them to the new tweeters. He worked with GR Research in Texas using their test facility’s to dial them in. Not only did they modify the crossovers for the new tweeters but they upgraded some of the parts to increase the performance even further. He feels the 2.7's with the new tweeter from the current EP 2.8's is the best version of EP speakers ever. He says the paper cone drivers of the older 2.7's have better tone than the carbon fiber of the EP 2.8's. He is helping me get the most out of them. So cool to be working with people who know your products inside and out. He is a super nice guy. Thanks Mark!

I have heard Clayton is very helpful as well. So nice to have folks in this industry willing to be so helpful. Don’t be afraid to call and ask their advice.

OBs are surreal. You’ll never go back to boxes. That said, dust can be a problem for those living in or near the desert or even in coastal Southern Cal with OCD. 

One of the most exciting sounds (OB or box) I ever heard was the Linkwitz LX Studio and Orion. The naturalness, the dynamics and the soundstage are uncanny—surreal, as above! But you need space and the right amplification

A few years ago, I heard the Spatial in Chicago audio show, and they are very impressive speaker, I would want to hear the new M5 Sapphire.

You can put together a fine open baffle set up for 25% of what you'll pay for the Spatial's. 

Lii Audio offers their flagship full-range driver for $1000.  It is 100 db efficient, and you can have a mid size baffle built, and power it with a low power tube amp and have absolutely wonderful sound. I have $1300 in my open baffles, and could not be happier. Here is a YouTube clip of what I have. Don't try to judge the sound from my iphone microphone. This is for the look only:

https://www.youtube.com/watch?v=b_yrG3ZzE1g&t=80s

I started using open baffles about 2 years ago, and I could never go back to a box speaker now.

I can certainly appreciate the DIY open baffles. Not sure that's me. I would like to rely on the very knowledgable designers and engineers to do the integration, testing and presentation for me and that is really what you are paying for. That said, since my initial goal was to replace my older Vandersteen 2ces I see that there are quite a few companies with the OB design. Pure Audio also looks interesting in the modular open architecture approach. Anyone out there own anything from PAP or comparisons to Spatial? Liking the Trio15's vs the M3 Sapphires 

I am new to OBs, but am now a convert. I was a big Vandy fan, but having now experienced Spatial, I find them much more enjoyable. See https://www.audiocircle.com/index.php?topic=165532.0

Quad speakers are open baffle in design, you have a front wave and the back wave is just as strong to the point you could flip the speaker around and you would have the same output. No woofers, no midrange, no tweeters, yet the speakers reproduce a recording with speed, clarity, and a bottom end into the '30s in a real room and a fast pair of subs to roll at 40Hz down and you really have something special. No distortion for sure, in fact, lowest of any speakers, so Spatial and their design as a lot going for it, and the knock of possible issues is due to others not understanding the work and the drivers they use are for the open baffle design are for open baffle designed speakers. I take what the Quads do right against any speaker at any sane price, and live with the few things they may do as well as a box speaker, but from experience, the Quads work so well in a normal living room is because they are not a boxed speaker, where you hear the bass, the mids and highs with separate drivers and you hope the design can blend them as good as possible and then you hope you can get them to work in your room. The room is an issue is gone with the Quads and Spatial speakers and that is why they both sound as open and natural, the Quad speakers still do it better because there are no drivers so the coherency is unmatched. Spatial solved the bass problem that is for sure.  

genovanelli

https://www.youtube.com/watch?v=b_yrG3ZzE1g&t=80s

Impressive stuff, not to mention setup!

Good to see Open Baffles doing so well in 2020.

As gregm mentioned above, if they were good enough for Siegfried Linkwitz, then they're certainly worth investigating for most of us. 

All those hugely complicated Gordian Knot box issues - dismissed at a stroke.

Why Open Baffle RULES... 
 
https://www.youtube.com/watch?v=lYaYCgwmHi8