General Speaker Advice and Recommendations

Discussion in 'Speakers' started by shotgunshane, Mar 7, 2017.

  1. ultrabike

    ultrabike Measurbator - Admin

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    I get 70 Hz flat w/o any equalization or "boost". The F3 is at 65 Hz. The F10 is in the mid 50s. The driver is designed to push a lot of air through the port. To avoid port noise, the optimum port diameter is about 1.5". The only attenuation I get in the woofer is to compensate for baffle step and to crossover.

    The specific driver I use (ND91-4), is designed to do this. It is not a dedicated mid-range driver (I would chose something else for something like that). It is also not the best full range there is. But it is optimal to for a woofer in a small vented box.

    You really need to design some things on your own to become more knowledgeable on these things.

    You are very outspoken. But seem to understand little.

    This is different from what many here mean by active XO.

    This is indeed one way to do things. However, digital manipulation only works optimally on a particular listening location. It is up to the drivers and system to perform optimally in as large an area as possible, or not depending on the goals. There might be other consideratons, such as pairing specific equipment with different characteristics.

    I've seen what you are doing. And it's a good solution.

    From what I've gathered, you are not shooting for an omni-directional response with large drivers at the expense of sensitivity (like Linkwitz). It seems you are aiming for high sensitivity and synergy with a carefully selected amplifier. You are not averse to equalization and you take care not to overdo it. Your system seems more alike what one finds in certain theaters.

    You have experimented with a lot of different designs, and have arrived to what you currently have through your own efforts and experience.
     
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    Last edited: Nov 20, 2018
  2. Psalmanazar

    Psalmanazar Most improved member; A+

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    Higher excursion means higher distortion though. It has rarely, if ever, worked in practice as well as a higher surface area part. Stories of such ultra-high excursion drivers vanquishing large monsters are mythical and come only to us from the deep past and the shadowy realms of the internet from which mortal men may not return. Not even Sennheiser's mighty Teutonic engineering or Bruno Putzey's strong DSP magic have made it really work so seemlessly. Only the mythical gods of the shadow realms who are nourished by beating hearts cut forth from the chests of redditors.

    "Purr1n has conquered the diy audio kingdom without seeking out all pieces of legendary gear to forge his chain. He succeeded with Behringer products. Should he import into the second quest to slay the DSP wizards raiding the Mushroom Kingdom, he shall be blessed with a permanent endurance bonus for his fortitude."
     
    Last edited: Nov 20, 2018
  3. purr1n

    purr1n Finding his inner redneck

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    Oh, by digital manipulation, I meant basic EQ, time delay, phase adjustment, crossover slope knee, etc. I'm not a big believer in convoluting impulse responses yet (pun intended), for the reason that you mentioned. The other aspects (dispersion, SPL, non-linear distortion, etc.) must be done with parts selection and design, e.g. crossover points.

    What I'm saying is stuff like time delay is better implemented in the digital domain rather than slapping two all-pass filters in series using opamps a la Linkwitz.
     
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  4. philipmorgan

    philipmorgan Member of the month

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    I'm actively (ha!) working on building a bi-amped system using this approach. Planning on doing volume control digitally until I feel like paying for a good passive line-level volume control that can handle four channels on the same volume knob.
     
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  5. ultrabike

    ultrabike Measurbator - Admin

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    Excursion gets largely reduced by the port.

    There are drivers that are designed to support large linear excursion, and they work well.

    There is no "vanquishing" of large drivers by small drivers jihad, nor does it make sense. One thing that small drivers (relative to their bandwidth) do well is dispersion. There are trade offs. If one wants a lot of SPL, a relatively large driver is needed. But one should be careful about beaming (this may require going 3 or more way). If one puts together something with a lot of drivers then one should be careful about listening distance.

    I'm not sure why you seem to be on a crusaide for exhalting large speakers, or why you are getting off the rails with "Teutonic engineering", "Bruno Putzey", "Mythical gods of the shadow realms" and all that stuff. That's just noise.

    You pick the right tool for the job, and foget about this flowery language and aimless large speaker crusade. You want high sensitivity? Then get large speakers with low xmax and high SPL. The low xmax should limit low frequency extension to maybe 40 or so Hz, but you will geet 90+ dB SPL where other speakers will give you only 80 or so. You may not get a lot of dispersion unless you go 3 or 4 way. You want to avoid too many passives because you don't like them, then use DSP xover. Forget about open baffle since that sacrifices sensitivty. Use tweeters and mids that are horn loaded and sealed. Good compression drivers will do. You will have a large speaker so plan for it. And that's that.

    This is a valid approach. But it's not the only one, nor is it perfect.
     
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  6. 9suns

    9suns [insert unearned title here]

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    I agree that most of the active solutions are sub-optimal (crappy amps, op-amps. etc inside the speaker) compared to a passive speaker with a really good amp, that's why I want to get my next speakers with an outboard pure class A, discrete (JFET) crossover and two amps of my choice (Linn LK85 or LK100, which are fairly nice sounding amps for the price), that would have the benefits of both approaches, and IMO should be how active speakers should be done. I'm still waiting (like many people, I suppose) for First Watt's promised new active crossovers (with BSC and some eq for the drivers if needed).
     
  7. ultrabike

    ultrabike Measurbator - Admin

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    Like @purr1n and many others, you could use passive speakers with no passive Xover, and do all the Xover at the source. This is a different form of active Xover.

    Looking at the miniDSP products and applications could give you a hint. Similar things can be acompished with similar products from Behringer and the likes. You get quite a bit of customization as well. And you can pair the preout of the active Xover with a set of amps of your choosing. Including a First Watt, assuming your speakers are sufficiently efficient.

    Others do the Xover at the soundcard, if the soundcard supports it (multiple outputs) and if using a solution integrating a PC or something similar. I think @OJneg does something like that, but not sure.
     
  8. ultrabike

    ultrabike Measurbator - Admin

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    BTW guys, I had in my mind the Jamo R909 speakers some time ago. They are open baffle larg driver 3 way with 2 15" drivers to handle the bass. It includes a 5.5" magnesium Seas driver, and a Scan Speak 1" tweeter. Sort of the high end COTS open baffle deal (35 Hz to 30 kHz). The sensitivity is 89 dB given this is an open baffle design:

    https://www.jamo.com/products/r909

    Then here comes this little thingy:

    https://www.jamo.com/products/ds7

    https://www.crutchfield.com/S-VU6D9WbYLZ7/p_701DS7WH/Jamo-DS7-White.html

    https://www.amazon.com/Speakers-DS-7-Subwoofer-Wireless-Bluetooth/dp/B077ZP7MGB

    First time I see an open baffle computer speaker like this.

    Anyhow, if I wanted to do an all out open baffle I would probably do an R909 clone w DSP active xovers.
     
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  9. purr1n

    purr1n Finding his inner redneck

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    I would be scared with soundcards, Windows OS, and Asus drivers to implement DSP crossovers on a computer. One hiccup and the tweeters go boom.

    More likely limited by the single metal mid which is horribly inefficient in actual use. It's inherently easier for large drivers, big woofers to have higher sensitivity. They are doubling up here too. The Eminence Beta 15s I'm using are 98db and will stay flat down to 48Hz (-3db point) where it then takes a dump in response (OB rolloff) in a 2' wide baffle. I suspect Qts is higher than specs indicate, or Qts skyrockets when the cone moves a fraction of a millimeter.

    Let me know if you ever want to attempt such a project. I have x4 of those magnesium Seas and x2 betterer Scan-Speaker tweeters to those. They are setting here on the shelf doing nothing.
     
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    Last edited: Nov 20, 2018
  10. rlow

    rlow A happy woofer

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  11. westermac

    westermac Friend

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    They measure well enough, but I'd expect midrange detail to suffer with such a high crossover point on a 10in woofer.

    I had a pair of BM15p for awhile which I believe also had the 10in crossed over at 1.8kHz... bass and treble were great but there was a midrange haze I couldn't get over.

    It's asking a lot of a large woofer to move that fast (perhaps why we don't see many 10in, 2-way configurations).
     
  12. mitochondrium

    mitochondrium Friend

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    Hi,

    I think Psalm is right, when he assumes that most people forged their view of active speakers while listening to crappy ones.
    Along the lines of active with external crossover and horns:

    https://www.abacus-electronics.de/p...-version-fuer-externe-signalverarbeitung.html

    coaxial horn with Beyma compression driver sounds very nice, unfortunately after a horny half an hour listening to these at a show at + 90 dB my tinnitus came back with a vengeance, so I am off the booze for now. Impressive how loud they go with very llow distortion.
    You need to switch to English on the top right of the website, probably not available your side of the pond.
    The version with computer based xover uses acourate software:

    http://archimago.blogspot.com/2015/11/measurements-digital-room-correction.html

    Which IMHO is the best all around tool for DRC/Xover design.
    At the moment I am using filters created with DRCDesigners, Uli created test filters with acourate based on my REW measurements (using the same target curve) and they sounded better, music was even less blurred.
     
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  13. purr1n

    purr1n Finding his inner redneck

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    I so highly approve of this. At $1200+ for the kit with cabinets, people should be getting this as their first real speaker instead of exotic 3" or 15" wider banders. Seas has always been brutally honest with their measurements - so keep this in mind when looking at the frequency response measurements.

    Get something that sounds normal (and with a bit of flair) first before trying to be all "pro and shit". Don't be that young artist with great ideas, but who can't draw, trying to be Dali. I purchased and made traditional designs first, starting with car sub boxes and moving up MTs and MTMs, before I went on the non-traditional path.

    If you can put together Lego sets, you can put this together. If you can't solder, use twist on wire connectors. I use them (or nuts and bolts) in a pinch for tweaking crossovers to change parts quickly.
     
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    Last edited: Nov 20, 2018
  14. Cspirou

    Cspirou They call me Sparky

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    It also seems to be the choice to go with high WAF narrow baffles

    http://www.troelsgravesen.dk/OBL-15.htm

     
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  15. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    I assume you're referring to the build aspect - cabinetry and so on? I enjoy technology but am not 'crafty'. For example I turbo'ed my Miata using a MoTec in piggyback mode when no-one else was using that ECU. I did all the wiring, base mapping and lots of tweaking including water injection and that's the stuff I really enjoyed - second only to actually driving the car. But when it came to the big parts installation - manifold, IC, exhaust, clutch and all that stuff I went with reputable kit pieces from Flyin' Miata and had a good shop do it for me. I don't care enough about that aspect to get good at it.

    I doubt any foray into DIY speakers would be different. I use patience (it was a second car and I had never done something like that before so it needed to be able to sit as long as it took), I defer to experts (I had a MoTeC guy come out and sanity check the installation and base map before I stomped on it) and I do lots of research and spend money on good quality kit (as far as my research allows me to identify). So with DIY I would outsource the build element to those who are better and care more.

    My end goal is to have a great system to listen to music with in a great environment at reasonable cost with good value. Which means vaguely I am more inclined to spend more money on more value. How much all depends. A good indicator may be that I modded a Miata versus buying an Evo. That paints a good picture about what appeals to me and what I'm prepared to invest in it and how far outside of convention I am happy to live.

    Right now it's just research, we will move into a bigger house sometime in the next 6 months or so and I have buy-in from my wife for a listening room that is WAF exempt. So I'm learning about everything from acoustics to speakers to electronics that will play a part in making that space.

    However I am open to starting on something more basic if it teaches me something valuable. I am wary of getting all excited and running down the "pro and shit" road. Which is a long way of asking does this advice apply to me?

    <edit> Note I am not committed to DIY or anything at this stage. I might just pony up for a set of ATC SCM50's and call it a day, but the HE horns + Bass bin idea is very appealing intellectually.</edit>.
     
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  16. Serious

    Serious Inquisitive Frequency Response Plot

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    I know it's off-topic, but what that guy needs is broadband absorbers to correct for the higher reverb time in the upper midrange and not a FR correction, or at least I think his FR already seemed excellent from the 10db/division graphs while the RT60 graphs made me shudder. The phase correction is nice, but I still wonder if it sounds better.

    @purr1n Have you heard that kit? I'm asking because the 10+1s I've heard always had a terrible beaming/dispersion mismatch in the upper midrange. Steeper crossovers and a larger waveguide would probably result in more even dispersion characteristics, but I can't say I liked any of the 10+1 speakers I heard. I feel 8+1 with a waveguide is already problematic enough.
    Sure, it's a 1.5" tweeter and the crossover is lower, but I'd still want to see FR measurements at 60° off axis or so. The Seas spec sheets don't look too bad at 60° off axis and the cone profile looks very flat so maybe it works better than usual.
     
  17. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    The Acourate stuff looks fascinating. Choice of ASIO media player-->AcourateASIO Driver-->Acourate Convolver with Linear Phase XO filters-->Dangerous Convert-8-->8x Attenuators-->8x Power Amps-->any configuration up to 4 drivers per stereo channel for the most flexible digital stack you can imagine.

    Only issue is by the time you're 70 you won't be able to figure out how to play music on it anymore.
     
  18. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    You could even run a DAW with filtering/limiting plug-ins and do channel routing this way. Attenuate line levels for max DR/SNR and put caps on tweeters, unless you like to live dangerously. Heck, buy a 4-stack of Schiit DACs and you will be able to do it, no need for a multichannel DAC.

    I plan to use my ADI-2 Pro for inputs from other sources as well and then keep a 300$ mac mini for DSP/streaming duties only.
     
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  19. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    The geek in me is all for it, and I know there are folks on DIYAudio doing this, but my gut says going Media Player-->Yggdrasil-->Aficionado-->speaker taps to horn and line out to Active sub gets you possibly better performance with 1/100th of the fuss. This is kinda what @purr1n is after if I understand it right.
     
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  20. crazychile

    crazychile Eastern Iowa's Spiciest Pepper

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    It's funny you brought up the Jamo open baffle. I hadn't heard of that before. Coincidentally, I've been entertaining the idea of a DIY version of this open baffle:

    https://www.pureaudioproject.com/trio15-horn-open-baffle-speakers/ - (for some reason this link wasn't working for me today, but it was yesterday.) I was particularly intrigued by the version that uses the Heil tweeter. Since the Heil plays down to 800Hz, I was thinking I might be able to use the standard Eminence Alpha 15 drivers and avoid that huge spike in the 2kHz range. Speaker components cost per side would then be a little over $300, and then I could look for some active Xover solutions to dial in everything. The biggest challenge/cost would probably be the mounting frame. Might be a good project for my son who started MIG welding in a high school class.

    My buddy who is a hardcore Klipsch Heritage series fan, has been experimenting with the Heil tweeters on top of a pair of Cornwall II speakers and is pretty thrilled. (Klipsch tweeter disconnected). I haven't had a chance to hear them yet.
     
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