What driver specs to prioritize for nearfield listening?

Discussion in 'Computer Audio' started by viivo, Nov 12, 2017.

  1. viivo

    viivo Gawd

    Messages:
    575
    Joined:
    Sep 7, 2005
    I'd like to build a pair of basic powered bookshelf speakers for PC use, but I know many drivers are not made for nearfield listening. What should I look for when shopping for the drivers? Also I'd love to be able to use one of PE's pre-built crossovers - would they work or is a different design needed for this application?
     
  2. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    It's not as simple as just choosing drivers. You have to look at the finished product as whole and design it around your needs. If you're going passive you'll have big challenges adjusting the impedance and crossover tuning to get proper results. Active is way superior as you can use 24db/oct linkwitz-riley and often also DSP features. And have the benefit of not having to handle multiple driver impedances with your crossover.

    You should choose your drivers so that their directivity fields are about equal at your crossover frequency (the side radiation is matched at frequency).
     
    N4CR likes this.
  3. westrock2000

    westrock2000 [H]ardForum Junkie

    Messages:
    9,841
    Joined:
    Jun 3, 2005
    You could do all that stuff, but you would have to buy a calibrated measuring microphone as well as software to use the mic to measure response, the Dayton kit is good (I have that) or you can use REW (have used it, but prefer the Dayton suite for ease of use). And by measuring and using MiniDSP you can get the response just perfect. You also get the advantage of driver each with it's own amplifier channel because the crossover is being done at line level.

    But.....

    You aren't going to notice if you don't go that route. You can use a proven design, and get results that will sound just fine. Usually near field necessitates a bookshelf (don't see people using towers in near field very often). You can look at PE's pre-designed kits. The Overnight Sensation is popular, but the bass is going to be weak. The TriTrix has more bass, but is larger. These kits come with pre-made enclosures. Is that ideal, or were you planning on building the enclosure as well?

    But that is just the passive part. Do you already have something for the amplification, or will that need to be considered in the project as well?

    And I assume you are using "near field" in the more colloquial meaning of a desktop application and not in terms of commercial mastering application?
     
    viivo likes this.
  4. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    A coaxial driver is the easyest to get to work in near field. In near field the distance between the tweeter and the bass becomes a concern (polar patterns become bad in vertical axis) so if you can find a kit speaker based on let's say Seas T18REX/ACG in a closed box https://www.hifitalo.fi/uploads/files/products/aw7[1].pdf it's going to work better than average in near field.
     
  5. Rifter0876

    Rifter0876 n00bie

    Messages:
    18
    Joined:
    Nov 1, 2017
  6. cageymaru

    cageymaru [H]ard|News

    Messages:
    16,484
    Joined:
    Apr 10, 2003
    Oh you like Parts Express already. They have lots of information on speaker building in their forums. Click the Resources link on their page at the top right.

    Tech Talk is the place to go for the Parts Express forums. Really good information in there and guides like this.
    http://techtalk.parts-express.com/forum/tech-talk-forum/38661-the-speaker-building-bible

    Project Gallery is a collection of various projects that users have submitted. I love looking at stuff that other people are doing even if I never try it. Some people are truly talented!
    http://projectgallery.parts-express.com/

    I would like to go active like everyone was suggesting earlier. MiniDSP seems like a worthy investment as others have mentioned. For $100 you get active crossovers and time alignment so you can tweak all year long without having to buy new parts. ;) $100 is close enough to the price of assembled crossover that I'd go with that. Maybe one of the guys here can explain the difference in features of the $200 version and the $100 version as I have only read about them but never used one.
    https://www.parts-express.com/brand/minidsp/646
     
    viivo likes this.
  7. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    MiniDSP requires two amps though so it's going to be more expensive than a passive crossover.

    99% of cases a ready designed kit is the way to go with DIY. A successful self build requires a proper measurement device and a huge study in practical theory.
     
    N4CR likes this.
  8. IdiotInCharge

    IdiotInCharge Not the Idiot YOU are Looking for

    Messages:
    4,474
    Joined:
    Jun 13, 2003
    'Build'

    If you want to experiment, awesome. If you want to just get great nearfield sound, grab a pair of JBL DSR 305's and call it done :D.
     
  9. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    The 305:s are great in near field but aren't so suitable in far field. Their performance degrades a lot outside nearfield.
     
  10. IdiotInCharge

    IdiotInCharge Not the Idiot YOU are Looking for

    Messages:
    4,474
    Joined:
    Jun 13, 2003
    Sure! And good to point out, as they're not necessarily 'universal', which I may have implied with 'call it done'. However, for the nearfield purpose of the OP, I bet they'll surprise :).
     
  11. N4CR

    N4CR 2[H]4U

    Messages:
    2,134
    Joined:
    Oct 17, 2011
    PMPO is critical.


    /s

    Boonie knows his shit. I nearly started a sub manufacturing company and would not DIY loudspeakers for all the reasons he lists and more. Put a year of study in and you might do an acceptable job from scratch..
     
  12. viivo

    viivo Gawd

    Messages:
    575
    Joined:
    Sep 7, 2005
    Thanks for the replies. I think I will go with one of PE's bookshelf kits. I've only ordered sub kits from them in the past, but I can't see speakers being much more difficult to assemble unless extremely precise soldering is required.
     
    cageymaru likes this.
  13. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    I don't know how much those PE kits cost but you probably could skip the building part and match the price by purchasing a pair of Pioneer BS-22-LR:s or the Elac debut B5:s.

    Those two speakers are built by a world renown designer Andrew Jones and probably are far better than the PE set.
     
  14. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008
    I'd probably do the same thing. Who knows where the DIY rabbit hole will end up taking you.

    Getting your hands dirty is always great if you've got the patience and money. At worst(unless you roll a natural 1 and die) it costs you a few bucks and some time. At best you've taken the red pill and you have a fun, interesting, and fulfilling path in front of you.
     
  15. cageymaru

    cageymaru [H]ard|News

    Messages:
    16,484
    Joined:
    Apr 10, 2003
    This looks like an amazing speaker kit for all the stuff you get in the box. I saw it over on ZeosPantera's Youtube channel as an unboxing. Watch the video to see all the little extras that they toss in the kit. I bet these speakers sell for a lot more assembled.

    HiVi - DIY 3.1A - 3.1 Bookshelf Speakers - Near-Field Speakers - DIY Speaker Kit - Pair - Black.
    https://www.amazon.com/HiVi-Bookshelf-Speakers-Near-Field-Speaker/dp/B0721ZQXDG/

    Madisound sells speaker kits that range from affordable to window shopping drool. The really awesome thing about them is that you can buy those high end drivers from those speakers you never could afford but you always wanted.
    https://www.madisoundspeakerstore.com/speaker-kits/

    Troels Gravensen's website is where I go to drool over speaker design. He basically gives everything away on how to build his designs. You aren't allowed to build his stuff commercially and profit from his designs from what I remember. But yea go check it out!
    http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm

    viivo let us know how the kit goes. I'd like to hear about your impressions of it.

    Almost forgot to link the unboxing video for the HiVi kit.


     
  16. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008
    I'm tempted to buy one of those kits just for funsies. I don't have any place for near-field listening AT ALL, but it seems like fun.
     
    cageymaru likes this.
  17. cageymaru

    cageymaru [H]ard|News

    Messages:
    16,484
    Joined:
    Apr 10, 2003
    I'm all about the fun of building something with my own hands. I swear it adds at least +100 listening value to the experience. ;)
     
    dergreg likes this.
  18. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008
    Even a "basic" DIY that's basically a glorified puzzle is fine with me. If I spend my money on any DIY project it really should be on something flat/honest and loud/sensitive for my theater room. My SVS Ultra bookshelves/center are nice and all, but sensitive they ain't.
     
  19. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    Sensitivity comes with sacrifice either in size or bass extension. Small speakers are not efficient enough in bass frequencies.
     
  20. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008
    Small was a necessity before we bought the house we're in now. Here, though, I've got much more space available to me.

    As a stop gap I've built midbass modules and they're connected to LCR via separate amps and minidsp. Calibrated with REW and a umik-1.

    They actually sound really nice, although I've got some ringing around 40hz I need to treat. And I still need to play with the bottom end of my mid bass to get it a little tighter. I run them a bit hot for movies.

    Plenty of work left to be done, but I can enjoy it in the meantime.
     
  21. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    Are the boxes ringing at 40hz or your room? Often the room is the culprit.
     
  22. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008
    It is absolutely the room and t's only intolerable on my left speaker which goes well beyond 400ms, where the other speakers it drops below my noise floor right around 300-320ms. I tested placement of my other speakers in the same position and got the same read. Now I just need to figure out where it's being caused and there are 3 different points in the room that "concern" me without having checked the distance. I'm going to stick a giant foam-filled beanbag thing in the spots I think are to blame and re-measure.

    It's especially annoying because any room treatments are going to have to be extra custom thanks to my pitched ceiling and odd room heights.
     
  23. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    For 40hz only a limp mass resonator or helmholz is effective. You'd need several feet worth of foam. Another option is to get a sub or two and tune them so that they cancel out the ringing at 40hz.

    Dr. Earl Geddes wrote his thesis on treating small room acoustics with multiple subs.
     
  24. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008

    The foam is just to see if I can get it down AT ALL. The bag itself should serve as a sort-of limp mass resonator, though it certainly isn't something I'd be able to tune. I should really just fill the volume of the room except for my listening position with foam and just listen until I die of starvation.
     
  25. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    The resonator needs to be a rigid enclosure with only one side 'limp'. Also it has to be precisely tuned for the correct frequency. A bag will not function as a limp mass resonator :)
     
  26. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008
    I'm super lazy and was hoping to find where I'd get my best value for effort just by dragging the stupid foam bag around, but I'd need like 7' for 40hz at a quarter wave. I guess I'll just have to put in the work for my power corners and see where it takes me. I'll just start with my suspect spaces and see where that takes me before I go too nuts.

    It's a great space, and it didn't need much love to get it where it sounds "good enough", but this last push is just going to be effort effort effort if I want it done right.
     
  27. B00nie

    B00nie [H]ardness Supreme

    Messages:
    6,272
    Joined:
    Nov 1, 2012
    If you're willing to put some money in it, call Dennis Foley of Acoustic Fields.
     
  28. dergreg

    dergreg Cookie

    Messages:
    446
    Joined:
    Oct 31, 2008
    Ah, money, the only WAF I really have to worry about. :/

    I'll read his blogs, watch his videos, and build some boxes; see what I can do without breaking open every piggy bank in the house...
     
  29. pippenainteasy

    pippenainteasy Limp Gawd

    Messages:
    261
    Joined:
    May 20, 2016
    If you can afford it, a 70-20 or 140-10 RAAL ribbon tweeter. It has limited vertical dispersion, which tends to be a good thing as it reduces room reflections. Of course trying to find a woofer to keep up with the ribbons will be pricy too. Otherwise, generally soft domes make a good choice for a nearfield monitor, almost all pro monitors use soft domes as the reduced breakup modes versus metal drivers tend to make it less fatiguing for long term nearfield listening.
     
  30. Finn

    Finn Gawd

    Messages:
    888
    Joined:
    Sep 24, 2005
    Limited vertical dispersion makes it sensitive to positioning, the tweeter has to point straight at the ear. Otherwise the ribbons often sound nice (but some have bad distortion problems).
     
  31. pippenainteasy

    pippenainteasy Limp Gawd

    Messages:
    261
    Joined:
    May 20, 2016

    [​IMG]

    The RAAL's are world class. Most DIYers consider RAAL's 70-20/140-15 to be neck in neck with the Raidho ribbon tweeter. Outside of plasma tweeters, the only other tweeter that can match or exceed the RAAL or Raidho tweeter in transient response or decay is the Seas T29D001, a > $3k diamond tweeter.

    Yes, it is height limited, you have to raise the tweeter to ear level for sure. Generally you have to be no more than 10 degrees off vertically before it starts to drop off in output. I would say since you aren't output limited in the near-field, using room correction isn't a bad idea.


    [​IMG]
     
  32. Finn

    Finn Gawd

    Messages:
    888
    Joined:
    Sep 24, 2005
    Even more worrying than the drop in the graphs is the nonlinearity of the drop. This is going to be a problem in off axis listening in near field and far field with general power response. Otherwise the graphs look great.

    The RAAL tweeter seems to be 600-700 bucks a piece. It's a VERY risky investment for a DIY builder. There's so many ways to get the design wrong, especially with the lack of DSP and measurement devices. The midrange is much more critical than the 3khz up this tweeter provides, anyway.
     
    Last edited: Dec 9, 2017 at 7:12 AM
  33. cageymaru

    cageymaru [H]ard|News

    Messages:
    16,484
    Joined:
    Apr 10, 2003
  34. Finn

    Finn Gawd

    Messages:
    888
    Joined:
    Sep 24, 2005
    I haven't seen measurements of the Dayton audio tweeters but price wise they're a much better starting point for a DIY :)

    In general Dayton audio seems to be good value for money.