What makes a speaker suitable for nearfield listening?

Discussion in 'Speakers' started by 9suns, Sep 16, 2018.

  1. 9suns

    9suns [insert unearned title here]

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    @ultrabike Heard that one like a year ago, but not in my room. I've found it a bit metallic sounding for my tastes and also boomy in the midbass, it could have been the room but I was not moved by what I've heard.
    I have a soft spot for good soft domes, because I can be listening to Paco de Lucía at low volumes and 10 minutes later crank some Nate Dogg on that bitch :headbang:
    The only "nearfield" that surpassed my stupid demands with flying colors was the ATC SCM20 ASL PRO MK2, but I want to conserve my two kidneys :D
     
  2. msommers

    msommers High on Epipens

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    Great looking speaker, I've thought about their floorstander too. Why external crossover?
     
  3. 9suns

    9suns [insert unearned title here]

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    There's something very appealing to me about the clean bass and midrange performance of an active sealed speaker, the ATC audition was a revelation, I've owned Amphion One15s a year ago (passive xover, passive radiator, metal drivers) but sold them after the ATC audition and kept my JBL LSR305 with me (had other priorities at that moment).

    First Watt will launch DIY versions of active crossovers, thus something discrete, zero feedback and pure class A will be available for not much money compared to what a good passive crossover costs. It's also possible to buy 2x Linn LK100 or LK85 for 600-700€, so it isn't much more expensive than the typical approach of passive crossover + 1 amp.
    I don't want a digital crossover because I will use my Audient ID22 as a DAC/Preamp for the speakers and for a headphone amp, I have a smallish amateur home studio so it's a convenient solution for me, as I can record, listen to the speakers and switch to the headphones easily for both home listening or recording.
     
    Last edited: Sep 18, 2018
  4. Cspirou

    Cspirou They call me Sparky

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    Really depends on the driver what sort of enclosure works best. Drivers with a really strong magnet would be over-damped in a sealed enclosure. One of the lowest distortion monitors I've seen was ported.

    I would do it for flexibility to experiment. Start with a passive crossover and then try out active and DSP. Something like a miniDSP can't be built into the speaker anyway unless you get their plate amp.
     
  5. Priidik

    Priidik MOT: Estelon

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    If one desires dry, precise, fast bass, the big magnet lightweight driver is it, it will contribute to any enclosure. Closed, ported, OB/IB all can sound one note and slow in the compromise to get more low down response. Obviously total Q of 0.2 will yield totally unusable sub bass quantity in closed/OB/IB.

    I have found that small ported speakers are a toss up, but once it's 3 way with at least 10'' or dual 7..8'' bass, ported sounds better, more effortless in the same size. Here the 'midrange' that might play down to high bass is often in closed box anyways.

    One thing to keep in mind with small two ways is that ported will have significantly less excursion in high output, so less doppler distortion and 2 harmonic in bass, so in medium to loud listening it will be technically better in most areas of the spectrum, with only thing being worse is group delay.
    This is one reason why big ported speaker doesn't bother that much, group delay problems are really low down, where room will smear everything anyways.
     
  6. Poleepkwa

    Poleepkwa Friend

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    Couple of things I would like to point out here:
    - Sealed bass is a lot more inefficient that ported. You gain depth but you lose output. That is why there are a lot more ported speakers than sealed.
    - Efficiency in a small speaker is generally poor, so you lose even more sensitivity, by putting it in a sealed case.
    - A sealed speaker is a lot more forgiving when building it (DIY)

    Thank you for bring the First Watt crossovers to my attention.
    I am currently using some miniDSP as " practise" crossovers, so would be interesting to see how they compare.
     
    Last edited: Sep 18, 2018
  7. Ardacer

    Ardacer Friend

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    It's best to use dsp to find optimal crossover/eq, then try and port it to line level opamp analog :)
     
  8. 9suns

    9suns [insert unearned title here]

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    The speakers will be 30-40 cm (1 or 1.3 ft) from the front walls, and with a Satori MW16-P midwoofer like the one in the SB Ara kit, sensitivity would be 87.5 db 4 ohm in a sealed box (3 db less than a ported speaker), but is not a problem for this application.
    Passive crossovers suck power and diminish damping factor, with an active crossover and 2x 100 or 85 watts amps like the Linns I mentioned before sensitivity is not an issue.
    Room gain has to be taken into account, the 12 db roll off of a sealed speaker is nice on this application and the Satori MW16P-4 seems to be a state of the art driver for that, allowing also shallow slope crossovers. See the "Kairos" speakers by Jeff Bagby, in room response is flat to 40hz taking room gain into account.

    Why the First Watt crossover and not DSP or op-amp based crossover? SOUND! BIAS! :p
    Would you take a "class D op-amp sound" vs "zero feedback, discrete, pure class A" sound? I won't, specially when both options would cost more or less the same and power consumption and heat won't be an issue (it's a crossover, not a speaker amp). Also I already have a monitor controller/DAC/preamp, so digital makes no sense to me.
    Why external? Less vibrations, subtly better sound (I guess), more cabinet space for the drivers.
    I only opened the thread to know more about why some speakers are better for nearfield than others despite having identical drivers and similar size.
     
    Last edited: Sep 19, 2018
  9. ultrabike

    ultrabike Measurbator - Admin

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    1. Loss of sensitivity due to sealed design may not be a problem for your applications. But it is definitively not a selling point.
    2. Every room is different. Low frequency room compensation is not a selling point for a sealed speaker. You need an equalizer for that.
    3. Passive crossovers do not necessarily suck power or diminish damping factor. Depends on the crossover.
    4. The Kairos go down to 40 Hz because of the port, not the room gain.
    5. If I'm after performance: If the class D amp performs better than the class A amp, I would buy the class D amp. If the class A amp performs better than the class D amp, I would buy the class A amp.
    6. For low frequency room correction, that First Watt crossover won't help you much. A DSP will.
    7. I don't think you will have lots off issues with vibration if using an internal crossover.
    For nearfield, a ported design should work nicely. A DSP might help you out with room correction in near/far-field applications, while an external First Watt crossover will not.

    I have a feeling you are already set on something. You should just do it.
     
  10. 9suns

    9suns [insert unearned title here]

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    I understand your points, and yes, I'm more biased than some amps :D

    Btw, I've made a typo. the Kairos is flat to 50hz in room, not 40hz, but the measurements are with ports plugged and well away from the walls from what I've read in the parts express forum.
    https://meniscusaudio.com/wp-content/uploads/2016/02/Kairos-Write-up.pdf
    Also I'm more interested on how the speakers perform in the room (the less dips/peaks in the bass, the better) more than a ton of dsp eq to correct it.

    And yes I'm more or less set on something, as I said before, I started the thread more for academic curiosity (ie: why do I have to listen to this speaker 3 meters away and the other 1 meter away if both use the same drivers and look almost the same?) than for speaker recommendations.
     
    Last edited: Sep 19, 2018
  11. Priidik

    Priidik MOT: Estelon

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    You might want to explore higher order xo for best dispersion nearfield.
    The Satori MW looks very good on paper.
    I have the 8 ohm pure midrange of the same series and it does sound great in 3 way (prototype bastid) setup with PXO LR2 filters.
    However, I can easily tell that my 8050A-s have more seamless transition in nearfield moving my head around sweetspot = a more homogeneous sweetspot, I suppose.
    This is due to many things, but I bet the high order XO in Genelec plays a big part in this.
    The obvious trade of is that 8050A sound a bit artificial in comparison. You can't run away from this with active opamp based filter. I don't think it's the tweeter, like many believe. Alu domes can sound butter smooth.
     
  12. ultrabike

    ultrabike Measurbator - Admin

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    Regardless of order, for dispersion a crossover should be set as high in frequency as possible, but sufficiently low to filter out driver break-up.

    EDIT: Meant to say as low as possible to avoid beaming. Forget about the cone breakup stuff.

    A designer may choose a high order crossover because the driver either has a lot of tone issues that require compensation here and there, or to increase attenuation at some region where a driver performs horribly.
     
    Last edited: Sep 19, 2018
  13. Cspirou

    Cspirou They call me Sparky

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    Probably why there are a lot of subs with built-in DSP
     
  14. ultrabike

    ultrabike Measurbator - Admin

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    Yup. Those likely have no need for a First Watt crossover.

    Not sure if @9suns is thinking of an external cross over for the individual drivers inside the monitor though.

    EDIT: If the application is monitor <-> sub crossover, the First Watt might work just fine. But it does not replace the DSP. And it's a bit on the expensive side for what it does IMO.

    EDIT 2: Also note that I'm a bit biased against anything Nelson Pass. I try to be impartial, but I'm aware I cannot always succeed at it. So be aware and in some things do take what I say with a grain of salt.
     
    Last edited: Sep 19, 2018
  15. 9suns

    9suns [insert unearned title here]

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    No subs, just a two way monitor for a small room.
    I couldn't understand completely what you said about the crossover, I'm thinking about a pair of speakers but with no crossover inside, 4 binding posts per speaker, bi-amping and the active crossover in a box, separated from the amps and the speakers. I did a stupidly bad draw (I'm terrible at this things) to illustrate it better.
    SPEAKER-SETUP-NEARFIELD.jpg
     
  16. Priidik

    Priidik MOT: Estelon

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    One school of thought is the opposite, you get less of the narrow dispersion part of the mid/midwoofer into play with a low xo point.
    That must be then matched with a large tweeter that can handle it.
    Nothing necessarily to do with tone or midrange breakups sounding nasty (in case of the Satori it sounds good even widebander mode), just dispersion and beaming.
    Tweeter's dispersion is often much better in the xo point, this can sound 'off' even with all the efforts in xo tweaking.
    It's a compromise between dispersion and 2. harmonic. However, there are some exiting new large domes in the wilderness that undercut the lack of grunt issue.
     
  17. ultrabike

    ultrabike Measurbator - Admin

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    I understand. Give it a shot. In the absence of equalization and a more elaborate xover, I would be concerned about baffle compensation and tone control. Given differences in sensitivity, you may need to attenuate the tweeter a bit.

    In general, a great speaker build xover is much more than just a frequency range divider between woofer and tweeter. The xovers are custom matched to the drivers, and indeed consider and make use of the driver's impedance and sensitivity.

    I like wider dispersion. I definitively don't care for narrow dispersion.

    EDIT: Yeah I said it all wrong. It's the other way around.

    But if narrow dispersion is desired, I would not use the xover. I would look into waveguides.
     
    Last edited: Sep 19, 2018
  18. purr1n

    purr1n Desire for betterer is endless.

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    Baffle step.

    I believe the FW B4 is straight xover only and does not offer baffle step compensation. Baffle step accounts for reinforcement of the lows from walls. The frequency at which the lows start to drop is highly dependent upon the baffle width. This frequency is usually between 500-800Hz. You can probably get away with the B4 if you shove your speaker designs near the wall.

    However, if you want to move the speakers away from the wall, then baffle step compensation will definitely be needed. This is the reason why self-powered pro monitors come with such adjustments. I've had to dial in a shit-ton on baffle step compensation (which is really a shelf filter to lower the highs) on some skinny tower speakers I made a while back, like -6db. So, sometimes it's not insignificant.
     
    Last edited: Sep 19, 2018
  19. Ardacer

    Ardacer Friend

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    And that (baffle step), together with reflected radiation through cone, standing waves inside the box, diffraction, radiation through enclosure itself, strong spring like resonance of driver and enclosure when the driver is screwed in, is the reason the best baffle is no baffle.

    Also, higher crossover points cause a normal box system to no longer have controlled (let alone the optimal uniform) directivity, something to consider too.
     
  20. 9suns

    9suns [insert unearned title here]

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    Thanks Marv!
    The B5 offers baffle step compensation (but is for open baffle), I'm not sure about the B4. He said that he will release new active crossovers available for DIY soon (B4 and B5 are not available for DIY), I guess one of them will probably have baffle step compensation.
     

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