BWC (Big Woofer Club): Why Big Woofers Matter

Discussion in 'Speakers' started by nishan99, Aug 5, 2020.

  1. ruinevil

    ruinevil Acquaintance

    Contributor
    Joined:
    Nov 17, 2019
    Likes Received:
    51
    Trophy Points:
    18
    Location:
    Capital District, NY
    Home Page:
    [​IMG]

    My entry to the BWC. They don't go deep though, maybe 50 Hz on the floor.
     
  2. spwath

    spwath Hijinks master cum laudle

    Pyrate BWC
    Joined:
    Dec 13, 2015
    Likes Received:
    7,894
    Trophy Points:
    113
    Location:
    Madison, WI
    What are those/are those full range 15" woofers? Like any tweeters there? Seems like there would be major major major beaming with a woofer of that size.... like anywhere about 800 hz
     
  3. ruinevil

    ruinevil Acquaintance

    Contributor
    Joined:
    Nov 17, 2019
    Likes Received:
    51
    Trophy Points:
    18
    Location:
    Capital District, NY
    Home Page:
    They are Hawthorne Audio Silver Iris. I think they are crossovered at 1000 Hz. And yea, there a dome compression tweeter.

    Edit: Some crossover and back images: https://imgur.com/a/tgKvXDr
     
  4. Priidik

    Priidik MOT: Estelon

    Pyrate BWC
    Joined:
    Sep 27, 2015
    Likes Received:
    2,153
    Trophy Points:
    113
    Location:
    Estonia
    Mana sauce jars that aid soundstage and plankton: upload_2020-10-16_9-1-15.png
     
  5. ruinevil

    ruinevil Acquaintance

    Contributor
    Joined:
    Nov 17, 2019
    Likes Received:
    51
    Trophy Points:
    18
    Location:
    Capital District, NY
    Home Page:
    Jars filled with sand to keep my records upright. I still use them with some bookends now.
     
  6. Cspirou

    Cspirou They call me Sparky

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    8,200
    Trophy Points:
    113
    Location:
    Northwest France
    I saw a few posts about limited choices of big woofers, particularly outside of pro offerings. Well scanspeak released this:

    https://www.scan-speak.dk/product/38we-8582t00/

    This is part of the Ellipticor line-up which uses a non-circular shape to reduce the breakup modes that are part of more uniform drivers.
     
    Last edited: Dec 18, 2020
  7. AdvanTech

    AdvanTech Friend

    Pyrate BWC
    Joined:
    May 13, 2016
    Likes Received:
    1,667
    Trophy Points:
    93
    Location:
    NYC
    $1500+ per woofer, though. My goodness.
     
  8. Cspirou

    Cspirou They call me Sparky

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    8,200
    Trophy Points:
    113
    Location:
    Northwest France
    ¡Ay carumba!

    maybe stick with the pro woofers for awhile...
     
  9. Armaegis

    Armaegis Friend

    Pyrate BWC
    Joined:
    Sep 27, 2015
    Likes Received:
    7,467
    Trophy Points:
    113
    Location:
    Winnipeg
  10. Cspirou

    Cspirou They call me Sparky

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    8,200
    Trophy Points:
    113
    Location:
    Northwest France
  11. Cspirou

    Cspirou They call me Sparky

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    8,200
    Trophy Points:
    113
    Location:
    Northwest France
    I have a question for the BWC crowd. Large >15" woofers have a sensitivity of 98dB or more. Why do they advise to use high wattage amplifiers for the woofer if it's so sensitive?
     
  12. Azimuth

    Azimuth FKA rtaylor76, Friend

    Pyrate
    Joined:
    Nov 9, 2015
    Likes Received:
    6,838
    Trophy Points:
    113
    Location:
    Nashville, TN
    Home Page:
    I would say for two reasons...distortion and the inverse square law. Higher wattage amps are going to have lower distortion at lower volume. Those drivers have tight tolerances and distortion kills. My buddy has seen many a 15" Peavey drivers on fire by running them on less then adequate amps.

    Fender used to use D-120 drivers in guitar amps until they started burning up. So JBL increased the gap and made the D-120F which reduced the sensitivity, but they didn't blow up with distorted tube amps.

    Really you can run them on low wattage amps, just make sure it is clean good power. So many Klipsch amps run on flea watt tube amps.

    And the inverse square law for PA or sound reinforcement. Some newer drivers for line arrays have sensitivy rating over 100db.

    I still could be way off base.
     
  13. Philimon

    Philimon Friend

    Pyrate Contributor Banned
    Joined:
    May 6, 2016
    Likes Received:
    2,092
    Trophy Points:
    113
    Location:
    Portland, OR
    Ive been using tiny t-amp with open baffle 15” woofer + 3” wideband. Is this okay?

    [​IMG]

    Yes, that is their permanent position. They are for background music. - diyaudio manzanita with some alterations.
     
    Last edited: Jan 3, 2021
  14. Azimuth

    Azimuth FKA rtaylor76, Friend

    Pyrate
    Joined:
    Nov 9, 2015
    Likes Received:
    6,838
    Trophy Points:
    113
    Location:
    Nashville, TN
    Home Page:
    T-amps are fine. Most Pro high watt amps are similar topology.
     
  15. dmckean44

    dmckean44 In a Sherwood S6040CP relationship

    Pyrate
    Joined:
    Nov 17, 2016
    Likes Received:
    1,425
    Trophy Points:
    93
    Location:
    Peoria, IL
    If your preamp volume gets turned to max level and you accidentally start playing some music the low wattage amp will clip hard and possibly damage your voice coils. So you just have to be more cautious.

    Most commercial home speakers are over engineered so that they could do some light PA duty because you never really know what people will do.
     
  16. Armaegis

    Armaegis Friend

    Pyrate BWC
    Joined:
    Sep 27, 2015
    Likes Received:
    7,467
    Trophy Points:
    113
    Location:
    Winnipeg
    A few reasons that all combine together...
    1) your ear is less sensitive to low frequencies, so it takes a higher db to "sound" the same as the rest of the frequency band
    2) music peaks can be quite a lot higher than the average, and given every 3db is a doubling of power, that adds up very very fast
    3) you are far more likely to blow your speakers with an underpowered amp than an overpowered one
    3b) the gist of it is that an under powered amp will clip, and a heavily clipped waveform is basically a DC signal riding whatever your output device voltage rail is. This basically turns your voice coil into a resistance heater, and that's what cooks your speaker assuming the amp doesn't give out first.
     
  17. Cspirou

    Cspirou They call me Sparky

    Pyrate
    Joined:
    Sep 27, 2015
    Likes Received:
    8,200
    Trophy Points:
    113
    Location:
    Northwest France
    Re 3):

    But why only the woofer? Wouldn't this apply to the mid driver and tweeter as well?

    I have read many people say that you can drive the MT section with 25 watts from a tube amp or Class A but for the woofer they use a big pro amp or Hypex plate.
     
  18. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    89,778
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    You don't have to. I've run the big woofers hybrid with a high power SS amp. I've also run big woofers from SET and from low power class A.

    High power SS amp of appropriate quality will have better control, less rounded, and get incredibly loud while sounding clean. Bass takes a ton of power. You run out of gas quickly. High power SS does it cooler too, more efficient.

    For a home theater or high SPL electronic, definitely SS on the big woofer. But like what I said. Sometimes low power class A, sometimes SET even. It's what kind of sound you want, even at lower listening levels.

    Another idea is that bass frequencies don't seem to be as affected as mids and highs with respect to quality amplification. So the idea is throw cheap class AB at it for power. The Why Not idea.
     
  19. numbercube

    numbercube Acquaintance

    Joined:
    Sep 29, 2015
    Likes Received:
    98
    Trophy Points:
    18
    Location:
    Germany
    -a) because they can acutally handle high power: big voice coil surface area can handle the heat and large xmaxs can handle the excursion.

    -b) the sensitivity of low mass 8Ω woofers shrinks to ~ 92 dB in large bass reflex enclosures with low tuning frequencys (35 Hz, free field). Go open H-frame and you may get only 85 dB at 30 Hz.
     
  20. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

    Pyrate
    Joined:
    Sep 28, 2015
    Likes Received:
    4,276
    Trophy Points:
    113
    This largely depends on what frequency range does your woofer play at. Take a look at these graphs (note the X axis not being Hz, so take this more as a trend graph) -

    [​IMG]

    Every +1dB of SPL is a factor of 1.26, so 3dB is 2x power, 6dB is 4x power and 10dB is roughly 10x power.

    Now, looking at the graph below you'll see that different frequency bands actually require wildly different power (Rap seems to be analyzed before the cancerous trap snare took off)! When looking at the curve, you also need to take into account the continuous vs momentary power needs. There was once a test of how much continuous power can an average dome tweeter handle and it turned out that most cook at less than 10W of sustained noise. Of course, most music is power intensive only for brief moments, so even for tweeters peak power can be rather high to accomodate for cymbal crashes and such. For mids and less for bass continuous power demand will be higher. Mids also have the help of the bass driver and tweeter, depending how are the band overlaps sculpted. And bass has the help of room gain down low.

    With the above in mind, let's return to the original question.

    Do you like to listen loudly? A pro bass driver will go loud without breaking a sweat, after all, look at that Pmax for mids and Xmax for lows. As they say, quantity has a quality of its own! Twice as loud is 6dB of SPL and 4x power. Is your tube amp being up to it? Or maybe it would like about 20dB of extra headroom?

    Only doing background listening? The benefit will be less audible, but you can mix and match amps now. Use your fancy tube amp for tweeter and mids and maybe get a good Class-D for lows. Generally bass cares about two things - power on tap and damping factor. Of course, there are others, but if you don't have the two I mentioned, the rest won't matter.

    A separately powered bass section opens up two other interesting possibilities. Have you noticed that Troels puts Hypex plates for his big speaker bass sections? The main reasons are lesser power requirements for the amp and two more - you lose a huge inductor coil and get free room tuning (if you know how to measure, that is). Why lose the inductor? Damping factor. All inductors have some resistance, depending in the copper cross-section used in the coil. All this resistance is basically seen as output impedance by the woofer and will [probably] kill some of the control the amp has over it. How much? Is it audible? That's up to the listener. Big coils cost pretty penny and in the end there's no coil like no coil. The most audible impact will be from the option to digitally room tune the bass.

    That's my 2 eddies.
     

Share This Page