High Efficiency DIY Bookshelves

Discussion in 'Speakers' started by Griffon, Oct 1, 2017.

  1. Griffon

    Griffon 2nd biggest asshole on SBAF

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    As many of you have known, I recently got into the 2-channel world in an unexpected way. So now I'm on the quest to do some high efficiency DIY bookshelves (there are a bunch of reasons behind).

    The requirement:
    - Relatively mall space, will not be more than 6'x10', just on the desk. I'll likely to keep my room small even I move.
    - DIY, total budget 500CAD if possible.
    - 300B SET amp, 9.2Wpc

    Discussions with @JK47 and @Jh4db536 have led me into looking at the 7" SEAS:
    https://www.madisoundspeakerstore.com/approx-6-fullrange/seas-h1794-fea18rcz-7-full-range/

    @Marvey any insights captain?
     
  2. Cspirou

    Cspirou They call me Sparky

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    Seas is not known for high efficiency drivers. In fact the spec sheet says this one is 89db. While 9W might be enough setup on a desktop, I think people typically look for 94db when using a 300b.
     
  3. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

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    [​IMG]
     
  4. purr1n

    purr1n Desire for betterer is endless.

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    ^ This.

    The Seas drivers are not high-efficiency. 9W sure, but 9W isn't that much different from 3-4W. 89db is really pushing it, even at close distance.

    Now I have not heard them or used them since they look like a new offering from Seas, but here is what the Force tells me:
    1. I no like rubber surrounds. Rubber surrounds are great and last forever, like 72 years. But foam and paper surrounds are better for this application. The best are foam, but they don't last. Has to do with suspension (spider is another factor, but I can't see much, other than QMS, which seems OKish comparatively for a 7" but not great). Once you have a lower power high resolution SET amp, you want every little microvolt change to translate into cone movement and not get wasted into heat absorbed by the rubber. Seas it totally behind Fostex is terms of surround technology.
    2. Frequency response looks totally fucked up, like the Lowther. Seas is very honest with the plots, for better or worse. Fostex tends to fudge things a bit on their provided frequency responses, but I can tell you that their 6" and 8" Sigma drivers are going to be MUCH better. Note that both Seas and Fostex drivers will have a bit of upper mid shout. I use an RLC filter to get rid of this - so overall efficiency may be slightly lower if you go this route.
    3. Smaller magnet (higher Qts), but better lower extension than Fostex 6" since the Seas is a 7" with lower Fs. Still is going to suck and will require subs whatever way you go.
    4. You get what you pay for. Fostex and Seas are premium brands for sure and not cheap.
     
  5. Priidik

    Priidik MOT: Estelon

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    Do these instead: Quattro
    Very similar SEAS construction behind the driver wrt motor and chassis, only better surround, optimized dustcap and some other smaller tweaks. The dude designed it himself and really dialed in for wideband use.
    The size is pushing it though for bookshelf use, but as guys hinted before me 90+ dB eff and reasonably full range (able to play some bass too) speakers can't be fitted into backpack.
    It's more like 1500 CAD though, on top of that you need tools, place to build and quite a few work hours.
     
    Last edited: Oct 1, 2017
  6. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    Why not, they're called headphones! All jokes aside - efficiency, low end extension (and impulse response), max spl and size are all at play when designing speakers.

    Overall - most high efficiency desktop speakers won't be more than 91dB efficient. Something like this might also do the trick - http://www.troelsgravesen.dk/FE126E.htm
     
  7. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

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    I think this would a decent place to make some commentary on the root of the issue here. I'm seeing a lot of people on here like @Griffon who through reading commentary about the excellence of low powered SET tube amps from guys like @Marvey or seeing others like myself get them, end up putting the cart before the horse and buying similar amps without consideration for whether it is suitable for their circumstances, or if they even like the particular sound you get from such amps.

    I'd probably hazard that most people wouldn't get any additional listening enjoyment from an SET amp over a decent class A solid state amp, and may even get less due to the typically inferior bass control. Even sillier is jumping in with both feet without even figuring out what you want, and what engineering compromises you are willing to accept/accommodate. Transducer choice should be first and foremost, before any other part of your chain. Most people don't even enjoy horn sound, and even more dislike full-range speakers.

    Perhaps most importantly, don't get caught up with Keeping-Up-With-The-Joneses. Some of us not liking conventional tower speakers and solid state amps doesn't make us better, it just makes us picky in a peculiar and expensive way. Go listen to things, and buy what you like, not what others like.
     
  8. Cspirou

    Cspirou They call me Sparky

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    Sort of agree with @HitmanFluffy although I’m not sure a lot of people would consider high efficiency speakers unless they have a low powered amp to begin with.
     
  9. purr1n

    purr1n Desire for betterer is endless.

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    And there is push-pull too. More watts, better bass typically. Though is there a lot of crappy Chinese and Japanese push-pull.
     
  10. Serious

    Serious Inquisitive Frequency Response Plot

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    I have some ancient bookshelves. These are fairly big speakers and quite efficient. About 90db/W. About 15L (20x20x36cm) to put things into perspective. Much bigger than today's bookshelves. 8" woofer and oval 4"/6" widebanders. Closed box. Fairly high Fs, otherwise high efficiency wouldn't be possible.
    These speakers are flat to about 100Hz even with quite a bit of room gain putting them into a corner. -5db around 60Hz and -10db around 40Hz or maybe slightly lower depending on room modes. There's really not a whole lot of bass with that sort of efficiency and with a closed box. In a more normal listening setup there's almost nothing below 80Hz. Just trying to give you an idea of the price you have to pay for real high efficiency in a relatively small form factor. They don't sound like total crap though. You could say more lively than most modern bookshelves. Also I'm sure they weren't meant for 0 Ohm OI amps. With some really good modern drivers, a ported enclosure (or similar), maybe also slightly bigger and less efficient you could make a pretty good bookshelf I'd say.
     
  11. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

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    Do you even read? Speakers first, amps second. If you're beginning with the amp you're doing it wrong.
     
  12. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    I'd say - music first. Content should dictate the reproduction medium.
     
  13. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

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  14. purr1n

    purr1n Desire for betterer is endless.

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    ^ LOL so true. A good deal of my listening involves material from the late 50s and early 60s. The engineers at Capitol records knew what they were doing back then in terms of mic'ing, mixing, mastering, etc. Supposedly they had audio engineer "bibles" on how to do all this stuff properly. Minimal mic'ing and chains were used. To me, the golden age of audio engineering was during this time. I'll take the 0.1% tube distortion from people who knew what they were doing instead of the 0.0001% opamp pefection from the kid with zits playing in ProTools.

    On a good system, it's very difficult to listen to modern stuff, popular, college U, alternative, whatever. Even the classical stuff today isn't recorded, mixed, and mastered as well as the 60s stuff from Decca / London. With today's recordings, most people would be better served with an SDAC, Matrix- M-stage amp, and a HD600 or HD650; or with decent speakers, a pro power amp (replace fans with quieter ones).

    The recordings I use probably explains the large differential that I sometimes have with other people who have listened to the same piece of gear.
     
    Last edited: Oct 2, 2017
  15. ultrabike

    ultrabike Measurbator - Admin

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    The smallest full kit I could find (bookshelf) is immediately below, and while not a sensitivity star it is quite good IMO given size:

    http://www.diysoundgroup.com/waveguide-speaker-kits/fusion-6/fusion6-kit.html

    However if you don't mind an 8" woofer you might consider this one with more sensitivity:

    http://www.diysoundgroup.com/waveguide-speaker-kits/fusion-8/fusion8-kit.html

    If a "narrow" 8" driver tower can fit the bill, this one has even more sensitivity:

    http://www.diysoundgroup.com/waveguide-speaker-kits/fusion-8/alchemy-tower-kit.html

    I am personally more intrigued about the Solstice below (I agree with @HitmanFluffy in thinking about the speaker first and driving considerations next):

    https://www.parts-express.com/solstice-mltl-reference-tower-speaker-kit--300-708

    This because it seems to have decent sensitivity even given the alleged 30 Hz extension with also alleged low distortion and decent staging. I would prefer a small tweeter, but it probably factors into the sensitivity. The overnight sensation (OS) bookshelf is somewhat unique with it's small tweeter (there are other 3/4" tweeter builds but probably not yet as popular) which may contribute to it's staging capabilities. But the OS does not fit the bill in the sensitivity department.
     
    Last edited: Oct 2, 2017
  16. Cspirou

    Cspirou They call me Sparky

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    People should definitely go transducers first. But if you take amps out of the equation, what sort of person really goes for exotic horns (front or back loaded) as a first choice? It’s not something that you can easily audition at any hifi store.

    These days it’s far more likely that someone has an SET for headphones that also has speaker taps and then looks for the sort of speaker that would work in this setup.
     
  17. purr1n

    purr1n Desire for betterer is endless.

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    Horns really are not all that exotic: Klipsch. They've been around forever. I have not heard their most recent stuff and how it is tuned.

    I should hit up @musiqlovr and see if we can get a loaner.
     
  18. spwath

    spwath Hijinks master cum laudle

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    Horns in general are not exotic. But some types of horns are. Altec, JBL, and the like have made some pretty crazy and exotic horns. And then there is also horns like you have, for woofers.
    Pretty exotic altec:
    [​IMG]
    JBL:
    [​IMG]


    If those are not exotic, I don't know what is.
     
  19. k4rstar

    k4rstar Britney fan club president

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    All HMF is trying to say is that by going for the speakers first, super efficient or not, you allow yourself the flexibility to have any amplifier you want and can afford in the back of your mind. Speaker choice (and amplification) becomes one of quality and not one of necessity. By doing the reverse you are pigeon-holing yourself into speaker designs you may not even appreciate or are willing to live with the compromises of.

    This isn't common at all. In fact it's a very small niche of people who exist only in boutique personal audio circles and have little to no stereo experience. Not the correct approach to system building if a full-range 2 channel setup is your end goal IMO.
     
  20. purr1n

    purr1n Desire for betterer is endless.

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    Well then again, I did the opposite. I knew I wanted to stay SET (and eventually go TT).

    So it was matter of trying out / building different SET suitable speakers. They are all different and bring their own qualities to the table. There is a universe of different approaches even under the SET restrictions of flea power.

    But this is easy for me to say and do. I've got a good collection of drivers sitting on my shelf.
     

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