Bertagni SM-275: Should They Stay or Should They Go?

Discussion in 'Speakers' started by MCM_Fan, Apr 16, 2018.

  1. MCM_Fan

    MCM_Fan AK Subscriber

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    Swung by the local Goodwill on my lunch hour to look through their used vinyl section. Didn't find anything that appealed to me. Lots of like new 1980s Country and Western. Not my cup of tea.

    So, I swung back through the furniture/electronics section where I found the most usual pair of vintage speakers - a pair of Bertagni BES (Bertagni Electroacoustic Systems) SM-275 speakers:

    [​IMG]

    I hooked them up to a crappy BPC A/V receiver and a Sony DVD player and verified that they were functional and decided to take them home and give them a real listen.

    Many here are familiar with the Bertagni speakers. Some seem to love them. Some definitely hate them. They are certainly unique. I didn't pay a lot for them, but on the high side for a thrift store find. I have 14 days to decide if I want to keep them or return them for a store credit.

    Initial VERY brief (like 15 minutes) Impressions: Well, they certainly look cool and are VERY well built. They are very heavy given how thin they are. Those pedestals are solid oak, not veneer over particle board. I haven't check if the side pieces are also solid oak, but I wouldn't be surprised if they are.

    They don't like bass. I've read others say they are very weak in the bass, need to be paired with a good subwoofer, etc. So, I was prepared for them to be bass shy, but I also learned that not only do they not put out a lot of bass, they don't like being force fed. That's a little 14WPC Sherwood S-7100A receiver that I usually run with a pair of JBL 4301B Control Monitors, or their fraternal twins the L19As. With small bookshelf speakers, at low to moderate listening levels, the loudness control on the Sherwood helps fill out the bottom end. On the Bertagni's, even at low volumes, flipping the loudness control on just resulted in some really awful, boomy sounding bass.

    So, turn off the loudness control and just accept the lack of bass (or add a sub). I will say that in spite of what I assume is less than ideal placement, these things do image very well, and I suppose that's the whole point/appeal. The image has very substantial depth and breadth. Fans of the Bertagni's say they work well with jazz and some classical music. Not really my thing, more of a classic/alternative rock guy myself, but I could see that working. I can confirm that these aren't "rockers". My little JBLs (and bigger JBLs and Rectilinear III Highboys) eat them alive when it comes to bass impact.

    I also don't think I have the space to do them justice. Maybe in the master bedroom, but I'm already running a pair of KEF 104/2 Reference Series there that I love in that space/application.

    However, I know someone who has a teenage daughter that's into jazz and 1960s - 70s R&B. I have offered to help her assemble a decent system on a limited budget and am wondering if these might fit the bill - if they have the space for them. Since they are a Goodwill find, the cost is less than even a pair of bargain basement new bookshelf speakers (which will also lack deep bass and won't look NEARLY as cool).

    In any case, I have a small amount of Miles Davis, Dave Brubeck, Stevie Wonder and Aretha Franklin in my collection. I'll give them some extended listening time and see what I think. If I don't want them and can't find a home for them, I always have the option of returning them.

    Here's a few links I uncovered:

    NY Times article from 1982

    Blog post titled: The '70s Plastic Planar Phenomenon - BERTAGNI SM-275 RESTORATION

    And, from right here on AK: The misunderstood Bertagni Speakers
     

     

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  2. swechsler

    swechsler Frog Whisperer

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    I only heard a set of Bertagnis once, and that was when I was a kid a long time ago. I didn't get a long listen, and it was in a showroom, but they impressed me with their clarity and relative realism on an acoustic guitar cut (they obviously impressed me enough to remember them over 40 years later). That's about all I remember, though. I do know that the panels are made of thick polystyrene foam and aren't very flexible, ergo, they aren't capable of much excursion and that's why they don't like to be pushed - the voice coil was pushing on the panel but the panel refused to budge. I don't know what sort of distortion you'd get from that, but I can't imagine it would be pleasant.
     
  3. MCM_Fan

    MCM_Fan AK Subscriber

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    I moved into a townhouse about five and a half months ago. So, too much bass doesn't make the neighbors happy. I sold the Electro Voice Interface Ds and have been running some smaller JBLs downstairs and the KEF 104/2s in the master bedroom upstairs. I'm on an end unit, with only one shared wall, which happens to be the one shown in the photo above. So, the lack of bass isn't necessarily a deal breaker for my situation. I'll give them some serious listening time before I make my decision.
     
  4. frommerstop

    frommerstop Super Member

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    Rule number 1 of planar speaker placement, whether it's a di-pole, or bi-pole like a BES, is they must NOT be placed close to & parallel with a wall. This causes cancellation in some frequencies, and reinforcement of others.
    Actually BESs work pretty well perpendicular to the back wall - yes, I'm talking about faceng them towards the side walls! I know it sounds strange, but I've done it before with good results. Bi-pole actually create a " figure 8" shaped wavefront so depending on listening distance, you will get as much sound from the side, as the front or rear.
    Pull them out at least 2-3ft, and toe the in. If they're fully functional, that alone should do wonders. If they buzz, the motor needs to be reglued to the sound board, a common issue.
     
    Last edited: Apr 16, 2018
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  5. MCM_Fan

    MCM_Fan AK Subscriber

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    Thanks!!! This is most helpful. They are currently between 18" - 24" (estimated, I' haven't measured the distance) from the rear wall, with no toe in (as shown in the photo). I'll make sure they are at least 24" from the rear wall and try a little toe in.

    I haven't noticed any buzzing (fingers crossed).
     
  6. frommerstop

    frommerstop Super Member

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    Not a little toe in, but quite a bit, if you need to keep the within a couple feet or the wall... Picture the sound shooting out the back & bouncing off the wall, the closer they are to that wall the greater the angle needs to be to keep the sound from bouncing back at the speaker, cancelling the next wave.
     
  7. Donkey Karma

    Donkey Karma AK Subscriber Subscriber

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    Their not planars. They are Styrofoam cut outs in aluminum frames mated to a pair of exciters.

    I had a pair for a bit. Just got around to selling them about a Month ago. Respectfully, I wasn't a fan at all chopped off and the top and bottom. Bland mids and decent soundstage.

    Gimicy to me. I really wanted to like them
    I just didn't..

    Do not give them to much power you will damage the Styrofoam and the will raddle constantly.

    Just my .02, hope you enjoy the back out of them!!
     
  8. frommerstop

    frommerstop Super Member

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    Yes, by definition, despite your preference, they ARE in fact a planar speaker. They don’t work as planar magnetics, like Magnepan, or Eminent Technologys, rather like Yamaha, or Melior as pulsating panels, but a “planar” none the less.
    I would agree they are not particularly accurate speakers, but I have found them to be an easy to drive, and pleasant sounding design.
     
  9. Donkey Karma

    Donkey Karma AK Subscriber Subscriber

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    I would like to disagree with you here. But unfortunately, technically I believe you have me cornered. :)
     

     

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  10. Pio1980

    Pio1980 AK Member Subscriber

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    Open baffle would make them dipoles.
     
  11. swechsler

    swechsler Frog Whisperer

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    Dipole and planar are not mutually exclusive; in fact, the latter usually implies the former.
     
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  12. MCM_Fan

    MCM_Fan AK Subscriber

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    Thanks to all who responded. I have decided to return the Bertagnis. I spent considerable time listening to them and playing with placement last night. The best placement was 3 - 4 feet from the back wall toed in about 30 degrees. That's just not practical in my rather small listening space. And to be honest my little JBL 4301B Control Monitors simply wipe the floor with them in every way (better highs, much better lows and play a lot louder without sounding boomy). Plus the JBLs aren't nearly as picky about placement.

    To be fair, I have a lot more time and money invested in the JBLs (I spent more on capacitors for the JBLs than I did on the Bertagnis). With the optimal placement the Bertagnis did sound pretty nice with acoustic guitar and piano, but I listen to a wide variety of music and need something that plays lower, and given my living situaton, something that requires a lot less space to sound their best.
     
  13. frommerstop

    frommerstop Super Member

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    To be accurate, they are bi-poles, not di-poles. They radiate from front & rear equally, but IN phase, as a pulsing panel rather than 180 degrees out of phase like a di-pole such as a Magnepan, or Electrostatic speaker.
     
  14. frommerstop

    frommerstop Super Member

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    Understandable, they are not for everyone. But I confess I’ve had an itch to mess around with one of the larger BESs like 275s or 300s for a while, I think with the right tweeter & room placement, they might really sing. Unfortunately the bigger ones never seem to turn up far from the West coast.
     
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  15. Pio1980

    Pio1980 AK Member Subscriber

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    I don't understand how that could function as a pulsating figure 8 monopolarity dipole, unless the magnet was mounted on a similar diaphramatic panel and reaction allowed an equal opposing pulse in phase and polarity rearward.
     
  16. quiet

    quiet AK Subscriber Subscriber

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    Of course this is totally contrary to what those speakers are all about but I would mount them up out of the way on the bedroom walls/corners with a sub under the bed and see what happens. So it's a good thing they're gone.
     
  17. frommerstop

    frommerstop Super Member

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    They don't work as a piston like a cone, esl, ribbon, or planar magnetic driver. The BES's panel is litterally designed to vibrate in the way that would be called cone break-up on a conventional speaker. It's panel is really a sound board, like in a piano, the sound is created by exciting that board, sending ripples across it. Not unlike a Walsh driver in principle, just instead of a cone the "Geostatic"(Bertagni's term for thier driver) panel. Is laid out flat. The reason for the odd ear shape is to keep reflecting resonances from cancelling each other.

    Actually, Bertagni's own advertising probably explained it best as like tossing a stone into a pond, causing ripples across it's surface.
     
    Last edited: Apr 18, 2018 at 10:36 AM

     

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  18. Pio1980

    Pio1980 AK Member Subscriber

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    OK, I can "see" that. I don't know for sure if that is also how the smaller similar Yamaha ear panel speakers were supposed to work. Also the Fisher sound panel picture speakers.
     
  19. frommerstop

    frommerstop Super Member

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    Yes, as I understand it,Yamaha paid licensing fees to Bertagni for some of the features of those, though they were a design unique to Yamaha. I’m not sure what relationship Fisher had with them, though I’ve heard the were made by Bertagni.

    Latter designs by Meitner (Sumo & Melior) were different enough in execution that I don’t think they needed to pay Bertagni.
     

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