General Speaker Advice and Recommendations

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

  1. SineDave

    SineDave Friend

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    I disagree. You don't need a subwoofer to carry up to 150Hz. Most adequately designed speakers are fine down to 80Hz, or at least 100Hz with acceptable distortion parameters. Assuming you cross over around there, a well designed sub will have lower THD (sub 1%) below 100Hz, better output and deliver a much less "rolled-off" response on the lower end.

    I think it's a common audiophile misconception/bordering on dogma that subs don't produce "quality" bass, and my experience measuring full-range speaker setups has never proven that to be true.
     
  2. shotgunshane

    shotgunshane Floridian Falcon

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    Does anyone have experience with Tyler Acoustics? The new Halo 2 with 12" woofer looks pretty interesting.
     
  3. purr1n

    purr1n Desire for betterer is endless.

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    You changed the argument.

    My point was that a subwoofer won't help shitty midbass from 5" drivers (or OK midbass from 10" drivers). And that one should get the best and biggest bass drivers possible before taking into account the use of subs rather than thinking subs are a way to get away with smaller woofers.

    Also, it's a common misperception among HT guys that measurements tell us everything. FR, CSD, and distortion tell us a lot, but not everything.

    I use subs myself. I've got a sub with my Fostex BLH, another for saved for @brencho, and a really nice Focal sub sitting in my garage for a sub project.
     
    Last edited: Aug 9, 2017
  4. purr1n

    purr1n Desire for betterer is endless.

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    Yes. I still have the OB's in my garage. I used the Eminence Beta 15". Fs = 35Hz Qts = 0.58. They did better than I expected, so I assume the Qts was fudged a bit. It's probably higher in real life like near 0.8. The OB-A15neo has a Qts = .99, so this should work. I am assuming that since this is a custom driver, the Qts on the datasheet would be accurate. If the Qts is too high, we get will more OB low end extension, but at the expense of controlled bass. For reference, the Eminence (standard) Alpha 15s with Qts of 1.26, often used in DIY OB projects, sounded too blubbery to @OJneg.

    That positioning of three feet from the back wall is more than fine. You might need a sub to cover 20-40Hz. The other option is to "cheat" by using EQ or a shelving circuit to extend the low end down to 35Hz. Don't push it down to 20Hz to limit excursion. The Eminence doesn't have a lot of xmax, but that's actually a good thing. In a home environment, the 15" woofers will give you plenty of leeway.
     
    Last edited: Aug 9, 2017
  5. purr1n

    purr1n Desire for betterer is endless.

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    50% of the sound quality of REL subswoofers lies in their "secret" methodology (per their instruction manual) to crossover at a frequency much lower than one would think. This is a great example. The response is basically flat from 40-80Hz (given that there are room modes) with a crossover point at 80Hz. The slightly emphasized 20-40Hz is actually not a bad thing.
     
    Last edited: Aug 9, 2017
  6. murphythecat

    murphythecat GRU-powered uniformed trumpkin

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    yeah, the 20hz to 40hz boost is room gain, which is nice.

    even when measured in a free from,room gain position, at the lowest xo setting possible on the rel (30hz setting), it doesnt roll off before 60hz. I dont understand why REL market their sub with 30hz capabilities when there 30hz xo setting is not -3db at 30hz at all, but actually 60hz. weird.
     
    Last edited: Aug 9, 2017
  7. purr1n

    purr1n Desire for betterer is endless.

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    Haha. Well for them, it's a matter of being technically honest. The electrical point of the crossover is 30Hz, but in a real room with the sub in a corner, the acoustic point is higher. I've found this to be true with other subs too. It does depend upon the room.
     
  8. murphythecat

    murphythecat GRU-powered uniformed trumpkin

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    its still weird in that my REL sub would be totally useless with my shl5+ as they do not start to roll off until 60hz, id have a severe bump between 40hz to 60hz.

    but technically, if you say your sub have variable xo starting at 30hz, wouldnt it mean that the response would be -3db at 30hz?
    agreed, subs wont help the early compression and distortion occuring at even moderate volume with 5' or 6' based speakers unless a highpass is introduced. and I wouldnt trust the cheap on board highpass from subs.

    5" or 6.5" are helpless for bass for anything but under 80db spl playback. with 10db peaks, 80db would be about the max.


    I feel that i sorta solved my troubles however with integrating a passive 1st order highpass at line level for my p3esr. it truly cleaned up the sound, I can now play my p3esr VERY loud, it raised significantly the max power rating (I use a 50 WPC and I can now play it at maximum without the p3esr even struggling). I feel this is a solution more people should experiment with. I honestly dont think my P3ESR setup has anything to be ashamed vs my SHL5+ anymore.
     
    Last edited: Aug 9, 2017
  9. purr1n

    purr1n Desire for betterer is endless.

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    I threw in a 200uF cap for high pass on the back the Fostex BLHs which could be bypassed. With the circuit in, it's cleaner sounding, but more grainy, 5% more veiled, and 1% less resolving. It's in for Daft Punk. It's out for girl and guitarist music.
     
  10. murphythecat

    murphythecat GRU-powered uniformed trumpkin

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    I think I know why.
    with my p3esr, when they are highpassed, its obviously more resolving, cleaner. it removes veil quite drastically. but , in my preamp, the cap is always in the signal path and when I bypass the highpass I bypass the resistor with the switch. in your setup, id guess your switch bypass the cap. i guess what you hear as degradation is when you introduce the cap in the signal path that is not there (the cap) when disabled. maybe im wrong though
     
  11. Muse Wanderer

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    Thanks Marvey.
    Actually those specs you quote are for the SE (ferrite) model. The OB-A15neo (neodymium) woofers I'll install have different specs as shown in the last spec sheet on the PAP website. The Qt = 0.72 with Fs = 40.4Hz. The Xmax is higher at 6.03 which should help with low extension. The efficiency is improved to 94.6 db 1W/1m. The SPL graph is also smoother with much less of a peak at 1.2K. Would the higher Xmax of 6.03, compare with the SE model of 5.55, result in less distorsion and clearer bass?

    I hope that the serial first order passive crossover topology and neodymium woofer magnets will catch up with the Voxativ Ac-Pi-Fe ferrite widebanders. I will use a D'Appollito arrangement to enable better boundary interaction with floor and roof. The only issue I foresee is that the Voxativ drivers will be below ear level at around 65cm from floor. The baffles are tilted by 2.5 - 7 degrees upwards. Harry Weisfeld, founder of VPI, has the same PAP speakers in his system and he lifted the whole speakers up on custom platforms. I might use this solution but this may lose the baffle effect of the floor.

    I think 3 feet is wishful thinking from my part. The baffles are 54 cm wide and very intruding onto the living area. At best it will be 2 feet from back wall, maybe a tad more if I can toe in the speakers further. However towing in the Voxativs may potentially sound bright, and front firing the speakers may be the only solution for a flatter response higher up.
     
    Last edited: Aug 9, 2017
  12. SineDave

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    I think we do agree after all then - it's just a matter of preference. I also think that you should always go with the biggest drivers possible (within reason), I also prefer to do this, though depending on how high you cross things over, a bookshelf/monitor + sub setup can sound pretty magical when well integrated and in many cases is not distinguishable from a monolithic cabinet with 12" or larger drivers in it. The catch is, most people don't know how to properly integrate a sub or pair of subs with their mains.
     
  13. purr1n

    purr1n Desire for betterer is endless.

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    This is where we disagree. We need to push the boundaries of what is within reason. I'd like to see more people using 15" woofers. 12" at the minimum. Too many narrow tower speakers at the hifi shows. My thing is if I see a cone move, then something is wrong.
     
  14. purr1n

    purr1n Desire for betterer is endless.

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    Two feet is still fine. With the MTM arrangement, you will have a total of four drivers. Don't worry, they will keep up with the Voxativ. I actually preferred the cheapo Eminence Beta over the way more expensive Acoustic Elegance Dipole15 deals because the Beta's were faster. The AE were better in some ways (more heft), but there's something about the goo'ed treated paper sound that didn't sound right. The AE Dipole15 were actually kind of sluggish sounding.*

    I finally figured out it. The AE woofers I used had higher mms / BL than the Betas. Go figure, science and theorycrafting works.
     
  15. spwath

    spwath Hijinks master cum laudle

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    Speaking of altec 511b, I found a pair with no drivers for $50 on craigslist, but 2 hours away from me.
    Are they worth the 4 hour trip?

    Also saw somone trying to sell them with drivers for $600....
     
  16. purr1n

    purr1n Desire for betterer is endless.

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    @philipmorgan: If you do the DIY sound group stuff, go for the two way with the 12" woofer or the coaxial 10". Being nearfield in a small room, I'd opt for the coaxial. I am actually thinking of putting together a monster 15" coaxial myself. But then again I have some big Oris horns coming in.
     
  17. Serious

    Serious Inquisitive Frequency Response Plot

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    Actually from my nearfield measurements the Qts and Fs values were almost spot on. Higher Qts also means lower efficiency. And higher moving mass (the AE woofers) also means lower efficiency, which cannot be compensated by increased magnet strength.

    The OB-A15neo are pretty similar to the Beta 15A on paper. Bit of a higher Qts and Fs, so probably slightly more efficient with more of a 40Hz bump, at the cost of slightly less extension. I guess in most rooms the extension will be limited more by the back wall cancellation than the woofer anyway. Also a different cone, basket and magnet, so they sound a bit different.
    I'd be surprised to hear a bookshelf + sub to have the same coherence as one bigger woofer to cover the entire bass range. I find that you can still localize bass even at very low frequencies, or at least in my OB setup I can*. With a normal speaker with omni radiation it gets more difficult. Not only that, but the filters necessary to integrate the woofer mess with the timing. And the cone coloration, distortion profiles and attack/decay characteristics of the drivers will also be different. It might just be me, as I've never heard a bookshelf + sub that had good integration.

    *There's a slight amplitude difference between the left and right ear when it's just one speaker playing even at very low frequencies. Down to about 40Hz I think.
     
    Last edited: Aug 9, 2017
  18. philipmorgan

    philipmorgan Member of the month

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    My interest in the high-efficiency big woofer+horn stuff is because I want that sense of slam and forcefulness that I believe they'll deliver. Fatiguing? Bring it on. :) So I'm definitely hoping for a good ole SBAF cockblock if I'm barking up the wrong tree. My OSMT's + 10" HT-ish sub are room size appropriate, but they just don't deliver the sense of force and realism I want.

    RE: the coaxial stuff, I'm definitely interested. Would probably get some vintage Tannoy's if I had the budget and patience to shop around.

    Looks like US Speakers (http://www.usspeaker.com/coaxial speakers-1.htm) has the most options in terms of big coax speakers. Any quick tips on what specifically to look for there? (or elsewhere if I'm missing something)
     
  19. purr1n

    purr1n Desire for betterer is endless.

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    Two things to look for:
    1. Low end extension. A lot of the strictly pro stuff doesn't extend that low. They emphasize efficiency and power handling over extension. This why is some of the DIY Sound is better. They sell tweaked versions that trade some of this efficiency for bass extention since you don't need 100db sensitivity inside your Fortress of Solitude.
    2. Box size. Some of the pro stuff requires BIG cabinets. The Vas gives you a general ballpark of the cabinet size that you will need. Again, the tweaked versions on DIY Sound keep the box sizes smaller.
     
  20. Sylafari

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    I'll probably start with a Dayton Audio DIY Speaker Kit (seems like it is one I could do easily) and just see how it is. Luckiliy, the only thing I'm great at is wood work, painting, and finishing the speakers (painted model kits was my hobby).

    It is funny, I graduated recently in Electrical Engineering but to be honest all those years in school seems useless when I look at circuit boards of modern DACs and amplifiers, I have a general understanding (high pass, low pass filters, crossovers, etc.) and some more advanced understanding of some parts of the circuit but otherwise I still feel clueless :(. At least the speaker crossover circuit is fairly easy to understand :p.

    I was thinking about getting some Isoacoustic stands for my monitors (my LSR 30X are currently just sitting on a plastic desk with the rubber feet attached) but they seem a bit pricy, I was wondering if my newly useless textbooks can serve as a decent enough alternative in the mean time.
     

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