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October 2017
Enjoy the Music.com Review Magazine
Superior Audio Equipment Review
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Bastanis Sagarmatha Solo Loudspeaker
Dare to be different with this highly evolved open baffle loudspeaker.
Review By Clive Meakins


Bastanis Sagarmatha Solo Loudspeaker Review


  Anyone who's read my reviews over the years will have picked up that my go-to high-end speakers are by Robert Bastani, his Bastanis open baffle speakers in particular. Robert's latest open baffles are developments related to his earlier Mandala range which was available to DIY'ers as well as finished product.

In early 2017 Robert changed the Bastanis business model and now offers assembled speakers only. The Sagarmatha range is therefore exclusively available as fully finished product. According to Robert this switch enables him to produce a line of completely new component parts which are designed without price constraints. This lifts the already high sound quality of the Bastanis speaker line-up and ensures the build quality and the finish of the cabinets.

If you want a DIY project along Bastanis lines take a look at the Bastanis sister site Club-27.com. The kits use different drivers to the fully finished Bastanis.

Bastanis' Sagarmatha Solo use a very similar configuration to the previous generations designed by Robert but all new drivers are employed. The range will comprise the Solo and Duo; the Duo with doubled up main and bass drivers is due to be launched late in 2017 and a huge Sagarmatha Reference is planned for 2018.

The Sagarmatha loudspeakers are sensitive beasts; they pump out around 102dB at one meter with just one Watt so very little power is required. The bass from around 100Hz downwards is an active setup using the Bastanis non-symmetrical W-Frame concept with amplification from Abacus. Why Sagarmatha? It seems that Sagarmatha is the original Nepali name for Mount Everest. These speakers therefore have a considerable task to match such lofty heights!

When folks come across open baffle speakers for the first-time comments such as "when will they be finished?" are not uncommon – it is of course the lack of an all-encompassing box which surprises people. It only needs few words about the lack of boxiness to the sound, simplicity and the Bastanis wideband high-sensitivity approach to dispel most apprehensions. Auditioning does the rest.

I should describe something about the Bastanis recipe or at least my take on it.


The Wideband
As already described, open baffle is a big part of the recipe so for the main loudspeaker drivers there is no box, just a baffle to the front. The main driver is a 12" unit, this handles the vast majority of the frequency range, around 100Hz to over 8kHz, this driver is called a "wideband" for hopefully obvious reasons. Getting a driver to cover such a wide spectrum is not easy, Robert has developed the driver specifically for this purpose. Some the techniques include mineral and lacquer coatings for the paper cone. The paper cone itself is light, considerably more so than is typical for 12" drivers. At the centre of the cone you'll spot a nice solid wooden phase plug surrounded by felt pads which eradicate the last vestiges of cone breakup at high frequencies. Behind the phase plug and totally out of view is the voicecoil, this is wound onto a stiff paper former; this limits the power handling of the driver to 20 Watts.


Bastanis Sagarmatha Solo Loudspeaker Review


It may sound like these speakers won't go loud and for sure the wideband driver is not a pro-audio 150 Watt bruiser. At a sensitivity of 102dB/W/m, it only needs a couple of watts to go plenty loud. The wideband combined with the tweeter is a very kind 12 Ohm minimum load. The magnets used for the wideband will have audiophiles drooling; they are the highly desirable AlNiCo magnets. The theory is that for typical ceramic magnets the voicecoil moving over the magnet changes the magnetic field causing compression; the cone moves one way then returns but stops faster than it should – hence compression. AlNiCo magnets apparently don't do this. BTW, that's Aluminium, Nickel, Cobalt making up the name AlNiCo. The wideband driver runs without a crossover, there just an exotic padding resistor across the driver; the driver is therefore directly connected to whatever amplifier you choose to use – there's nothing to get in the way. As you can tell, this is no run-of-the-mill mass-produced driver, it takes weeks to finish the entire process to complete a driver.


The Tweeter
The upper frequencies are taken care of by a new development of the Bastanis Gemini tweeter. The Gemini is a very substantial piece of metal, the magnet is massively powerful. A cone diaphragm is used, this of course receives the Bastanis cone treatments. The tweeter is attached to a horn which is sculpted into the baffle. The tweeter is a 1.4" unit which is up on the 1" of the previous generation. At 1.4" there will be less turbulence within the throat of the horn which ought to make for an even purer sound. The tweeter is a dipole, it runs backless so treble is produced front and back, as with the wideband.


Bastanis Sagarmatha Solo Loudspeaker Review


The Bass
The bass driver is a very meaty 18" monster. You'll look at the bass section and think "hey, this isn't open baffle". You'd be mistaken though you'll be granted forgiveness. The bass enclosure is technically a non-symmetrical W-frame; it's in effect a folded baffle, not a box. The reason it's not a box is because it has a large slot to the front and a considerably larger aperture to the rear – hence my "folded" description. It's also ok to call the bass a dipole as it radiates sound front and back.

The bass is active which means it has its own amplifier. As is the case with all things Bastanis the amplifier is unusual. The amplifier is by the German brand Abacus to Bastanis specifications. The Abacus plate- amp has six controls: 

•  Auto on/off so you don't need to remember switch the amplifier on or off

•  Bass Volume: Set this for correct level to match the widebands

•  Low Pass Frequency: This is the crossover frequency with the widebands, it'll need to be set around 100Hz

•  Low Cut Frequency: If you have a large room you can probably set this to 16Hz

•  Distance Correction: Set any delay you need to match the widebands

•  Slope: Start with 18dB/Octave, 12dB and 24dB are also available


The Low Cut control is there to help with the rooms which have a problematic bass frequency. There are resonances which are generated due to the dimensions of any room. These are often somewhere between 30Hz and 70Hz. If you find a bass frequency dominates you can dial it down using the Low Cut control.

As to the bass amplifier itself, I've borrowed some text from the Abacus website to describe some of its uniqueness"

Similar to tube amplifiers, the ABACUS amplifier uses the collector (in tube amplifiers: anode) of the output transistors to drive the loudspeaker, instead of using the emitter (in tube amplifiers: cathode) as done in common audio amplifiers. The advantage of using the collector is that it is always able to provide the maximum current, independent of the instantaneous value of the voltage. Hence, ABACUS amplifiers operate independent of the load.

The difference to tube amplifiers is that ABACUS amplifiers do not use an output transformer. Furthermore, ABACUS amplifiers provide 100% negative feedback and the output impedance is exactly zero. From this follows that with ABACUS amplifiers, the loudspeaker is not simply excited, but guided in a controlled manner.

The built-in plate amplifiers are around 220 Watts – you get one per channel if you select this option. The stereo amplifier option is around 110 Watts; having tried the stereo version in my room I expected it to be way too puny but I'll state now that this was not the case at all. The setup I used most of the time had one bass amplifier per channel. The basses are fine with a single (stereo) amplifier; if the listening room is huge or the listener is after live hard rock listening levels a second stereo amplifier in bridge mode will extend the power output or just pick the plate amplifier version in the first place.


The Finish
Bastanis' Sagarmatha Solo loudspeakers are handmade speakers from the drivers to the baffles. As such you can specify a number of finishes, covers and colors. The main structure of the veneered versions is made from very high-quality ply - the sort that has no voids to color the sound. High-quality ply is an ideal material is as the grain runs in multiple directions diffusing resonances. The ply will be finished to your preference; the slate finish in the photos looks great in the flesh and works well with the modern d้cor shown in the photos. These speakers are not typical, far from it and I really like their statement looks.


The Room
It is important with any speakers to ensure the room is suitable; rooms can need well placed damping materials or furniture moving around to allow correct speaker positioning or as a technique to absorb or diffuse sound wave reflections. Open baffle speakers such as Sagarmatha Solo have their own specifics to take care of. Robert advises rooms of not less that 25 square meters; this approximates 18 feet x 15 feet which as it happens is the size of my room. Bigger rooms than 25 square meters are of course absolutely fine. I find two factors are particularly important; positioning the speakers at least 80cm / 30" from the side walls and placing the speakers such that they are a few feet in front of the rear wall. Take care of how reflective or absorbent the rear wall is, you should experiment a little. Don't forget there's as much sound coming out of the rear of the speaker as the front in the case of open baffle / dipole speakers. The active powered woofers always ensure the correct dose of bass combined with seamless integration to the baffles can be dialed in for any room, this is a big plus compared to fully passive speakers.


Eating The Pudding
As the saying goes, the proof of the pudding is in the eating. Will flying in the face of mass market speakers prove to be worthwhile? I was very fortunate to be able to listen to Sagarmatha for several months at home and I also auditioned another pair at the distributor premises in the Netherlands. It's very useful for a reviewer to hear speakers in totally different environments and systems.

At this stage I ought to declare my preferences for the sound I want from a system. I love music reproduced in almost any situation and settings but I do have a preference for my main system. The contrasting styles I have in mind are small stand-mount speakers with precise pin-point imaging versus a big soundscape which provides the illusion of a band playing in from of me. It is the latter style which I prefer. The pin-point imaging system for me is more cerebral and the big soundscape an affair of the heart. This is just my preference, you may be quite different. I wanted to state my preference so you'll know where I'm coming from when I describe the sound of the Sagarmatha Solo.

As the wideband drive units in particular have a lot of cone treatments there's quite an extended initial burn-in period of around 200 hours. That said, these drivers don't sound unpleasant during the burn-in period so it's not too much of chore going through the burn-in phase.

I'm very familiar with the original Bastanis Mandala open baffles, the Sagarmatha Solo deliver a similar – actually slightly larger – scale and soundscape; this means they paint a meaty, room-filling and believable musical picture. I was really pleased with the overall soundscape of the Solo so what were my initial stand-out impressions? Imaging and soundstage are fantastic, just as you'd hope would be the case with open baffle dipole speakers. I find the spread of the soundstage to be very consistent between and even outside the speakers; the area between the speakers is very well populated, it is not at all just left, centre and right. It's hard to describe in words but I'll try. The sound is painted with large dramatic brush strokes; no part of the canvas in front of the listener is left unpainted. Some speakers draw attention to detail but here because the Sagarmathas paint a large picture, details are not relentlessly pushed at you, they occupy a large space and are all the more natural for it.

The extremely transparent sound of the Solo is unforced and natural. I hear harmonics that frankly I've rarely heard outside of live music, it was listening to piano when I first noticed this. I then noted the textures and complexity on strings, again this is superb. The way the speakers cope with recorded sibilance is absolutely perfect for myself; it's a bugbear of mine so they are good – believe me. The Solo does not dial out nasties by dipping upper-mid frequencies, they instead deal with soaring and potentially piercing sounds by not losing control.

Bass from those big 18" drivers is well judged and to my taste. In my listening room bass extends down to the upper end of the 20Hz to 30Hz region before gracefully tailing off. In the deepest bass regions boxed woofers produce bass which is not so textured, it can even be a bit one-note sometimes. The Sagarmatha 18" dipole woofers stay clean plus they make recorded sonic signatures and textures audible. The speakers work well with all genres but especially well with acoustic instruments, real instruments sound real, maybe this correlates with the natural omnidirectional radiation of the open baffles, mimicking an instrument playing inside the listening room.


Bastanis Sagarmatha Solo Loudspeaker Review


I'm thinking double bass in particular; that said the likes of "Man Machine" by Kraftwerk pressurizes the room with sound waves and is deeply impressive so electronic music works well too. Both macro and micro dynamics are impressive; I noticed is that a change of pace from musicians is very easily detected. Clean, natural and believable are words that come to mind when trying to characterize the Sagarmatha Solo. By "believable" what I mean is the sound is a good illusion of live music, the scale and presence make you feel there's band in the room – providing the source, source material and amplification are up to it.

One of my loves is for late 1950s / early 1960s jazz in mono. Yes you can buy albums processed into stereo but I invariably find the music works best in mono with stereo speakers. This was especially case with Sagarmatha. The mono image is very strong between the speakers and is portrayed as a live band would sound. The beauty of mono is there are no tricks and gimmicks as can be used with stereo. The Sagarmatha sound is so lifelike in the first place and when listening to period recordings in mono the effect is enhanced. I've may have blown my credibility by talking about mono but seriously... try it.


Musical Examples
I auditioned the Sagarmatha Solo for several months so I'm not going to list all the music I listened to but I will run through a few albums and what I found.

Kraftwerk "Man Machine" from the live double Minimum Maximum has such clarity, dynamics that terrify with sheer visceral power.

U2's Joshua Tree may not the greatest recording but fabulous music, the Sagarmatha's brought order and clarity to what can on some equipment be a marginally confused sound.

Le Quattro Stagione / Vivaldi – Salvatore Accardo on the Fon่ label. I thought I knew the Four Seasons inside out, I simply love this rendition and the work done by Fon่ all the way through to control of the record cutting process. Exquisite.

Nanci Griffith's Lone Star State of Mind – the title track in particular is such fresh and infectiously happy sound.

London Grammar's If You Wait is a great sounding modern recording, emotional and powerful.

Jennifer Warnes' "Bird on a Wire" from Famous Blue Raincoat is a classic test track for me, as is most of album. I've over-listened to it but still the Sagarmathas highlighted some musical interplay I'd previously missed.

Passengers' Miss Sarajevo (Brian Eno, U2, Pavarotti) produced goosebumps; what more can I say?

Wynton Marsalis & Eric Claption "Corrine, Corrina" from the live album Play the Blues has incredible dynamics, presence, a live vibe that if reproduced well it leaves you elated. I've never heard it better than through the Sagamatha Solo.

Tom Waits' Nighthawks at the Diner had the Sagarmathas transporting me to the club... I was there, I'm sure I was!

Agnes Obel Aventine has ethereal vocals so wonderfully reproduced.

Of course I played lots of jazz by the likes of Art Blakey, Sonny Rollins, Dexter Gordon, Charles Mingus, John Coltrane, Dave Brubeck, Stan Getz.... I've loved it all. With the Sagarmathas I could forget about the equipment and listen. This is what hi-fi is for.



System Synergy
The system I heard at the distributor Live Fidelity in the Netherlands was built around Silvercore SE 833C transmitter tube monoblocks and a matching tube preamp. The source was an STST direct- drive turntable with Lyra Etna cartridge. Coupled with Sagarmatha Solo the sound was smooth, powerful and yes it did the believability trick. The essence of the sound was very similar to what I hear in my own room and system. Of course there were differences that you'd expect between systems and rooms but there were no surprises and the system sounded great. The 833C tubes are quite something... visually totally stunning and powerful too.

In my own room I had plenty of time to try various amplification options. My sources were my usual Trans-Fi Salvation rim drive record deck with London Reference cartridge, Garrard 301 setup as my mono deck. Digital was catered for by a fanless computer running the Japanese Nontallion player feeding in a Metrum Musette DAC fitted with the latest DAC TWO Broadcast modules. Trying out the amplifiers I had available I found the Solo to be so very transparent that the difference between amplifiers was more apparent than usual. The speakers are very clean yet free of harshness so there's no need to choose a euphonic amplifier. My 300B SE amplifier equipped with Western Electric 300Bs is luscious beast but it was not an ideal match for my taste with Sagarmatha. For the first time I found the sound the WE 300Bs to be just that little to colored or cloying. I found clean and neutral sounding amplifiers worked out best, which is as it should be. I love the latest Temple Audio Class D monoblocks, these run balanced and from linear power supplies. The Bastanis Panettone EL84 SE 3W amplifier was quite magical with just a hint of the SE sound without taking it to WE 300B coloration levels. For fun I recently bought a Quad 306 and serviced (replaced) some of its elderly components, the Quad sounded great too even if was not quite up to the standard of the Temple or Panattone. I'm convinced an OTL tube amp would be a fabulous match; I plan to build a Bruce Rozenblit 4W Mini Beast OTL amplifier kit.

My recommendation is to partner Sagarmatha Solo with the best sounding clean, neutral amplifier money can buy rather than an amplifier with a strong characterful sound of its own.



When I read through my review even I'm surprised that I've not sounded even more effusive. Bastanis' Sagarmatha Solo are amazingly good speakers. They don't leave non-audiophile listeners saying "wow, that's the most amazing sound I've ever heard!" That sort of comment often occurs when a sound is spiced up in some way, maybe even to the point of being surreal. Such experiences are usually a short-term euphoria which then turns to disappointment due to a stressful or tiring sound. With Bastanis' Sagarmatha Solo speaker we have a deeply – I stress deeply – satisfying sound which is wholly natural and believable. It's not quick euphoria that I feel with the Solo, it's a tranquility or complete satisfaction; sort of "yeah that just sounds so right". Definitely it's an affair of the heart. The choice of the world's best speakers is individual and dependent on different preferences. My personal feeling is: Yes, Sagarmatha Solo reach the summit of Mount Everest!

The Sagarmatha Solo floorstanders are not "Hi-Fi" sounding – that's a good thing – you forget about the equipment and are immersed in the music. Music can be played at any level quiet or loud, there's no particular sweet spot in terms of level. Micro-dynamics are excellent so low levels are exemplary. There's no harshness so high-levels are comfortable too.

I want to have music painted with broad brushstrokes and have it wash over me; there should also be great macro and micro dynamics, speakers should transparent, possess a full-range frequency response and be easy to drive. Bastanis' Sagarmatha Solo are ideal speakers such as I've just described. The speakers give the impression they are a massive pair of headphones positioned in front of me. With a good source and amplification, you really could not want for better speakers, unless perhaps you have a large room in which case the Sagarmatha Duo should also be on your shopping list.

Next up are the scores. I need to explain about the "Value for The Money" score. I struggle to give any piece of hi-fi a 5 at the price level of €16,000 (~$19,000 USD) – it's personal thing, it's a guilty Puritan streak I'm fighting with. It is true that I can't think of any better speakers for the money so that makes them great value by definition. If anyone reading this review wants to think of my Value for The Money score of 4.5 being a 5 that's fine, it probably should be.



Sub-bass (10Hz - 60Hz)

Mid-bass (80Hz - 200Hz)

Midrange (200Hz - 3,000Hz)

High Frequencies (3,000Hz On Up)



Inner Resolution

Soundscape Width Front

Soundscape Width Rear
Soundscape Depth Behind Speakers

Soundscape Extension Into Room


Fit And Finish

Self Noise

Value For The Money


Type: Three driver open baffle floorstanding louspeaker
Drivers: 1.4" dipole horn tweeter
            12" AlNiCo wideband
            18" active dipole woofer
Sensitivity: 102dB/W/m
Impedance: 12 Ohms
Power Handling Wideband: 20 Watts
Bass: 800 Watts
Dimensions 125cm x 42cm x 60cm (HxWxD)
Weight 60 kgs each
Price €16,000 (~$19,000 USD) for reviewed version, prices vary by options


Company Information
Weidenweg 8
55299 Nackenheim

Voice: +49(0)178-7117925
Website: www.bastanis.de


Netherlands Distributor
Assisted with equipment for the review.
Live Fidelity
Mitch Leighhof 2
3543 CP

Voice: +31 6 288 38 572
Website: www.LiveFidelity.nl














































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