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Scanspeak or Eminence Woofer?

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  • Scanspeak or Eminence Woofer?

    Hi All,

    Thanks for all the education from everyone's posts ...

    I need help selecting one of two woofers for my 2.1 boom-box design. I have no idea what SPL and F3 ratings will sound like on the beach.

    This will be used on the North Jersey shore near waters edge. In the early mornings we play softer side music (Sade, Michael Buble', etc.). In the afternoon, the party starts with Hot 100 selections from the past several few years. History has shown 30 to 40 people dancing in close proximity (i.e., within 10 yards or so of the box).

    So, I have no reference point for SPL in this situation. My driver choices have been modeled and are narrowed down to:

    Scan Speak W22-4534G: F3 ~45hz, SPL at max power (<1% THD) is 108db (102db after BSC).
    Eminence Deltalite II 2510-4: F3 ~64hz, SPL at max power (<1% THD) is ~114 (108 after BSC).

    I'd really like to have the low frequency extension for the softer music. And my design has active, adjustable BSC from 0db to a full 6db correction. I also account for cone excursion (active high pass) and port air velocity all in WinISD). My intuition is that I will not get any bass enhancement from the dead sand 1ft under the box's stand. The crossover for the woofer will be an active LR 2nd order either at 876 or 1073. The amp is a 2.1 TPA3116 running at a nominal 24v giving me ~55watts into these 4ohn woofers.

    Is there any way to relate sound level and quality via this description?

    Regards,

    Michael

  • #2
    Re: Scanspeak or Eminence Woofer?

    For outdoor application I recommend going with as much SPL as you can get. Apply some EQ for your softer music to boost the low end if needed.
    "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
    exactly a Fc 3K for both drivers, anybody can do it." -Xmax

    Comment


    • #3
      Re: Scanspeak or Eminence Woofer?

      Originally posted by dcibel View Post
      For outdoor application I recommend going with as much SPL as you can get. Apply some EQ for your softer music to boost the low end if needed.
      I was afraid that's where the collective wisdom would lean. That's not biased by your "handle" is it? -

      Comment


      • #4
        Re: Scanspeak or Eminence Woofer?

        Originally posted by dcibel View Post
        For outdoor application I recommend going with as much SPL as you can get. Apply some EQ for your softer music to boost the low end if needed.
        Hi Mike,
        Dcibel knows his stuff, dont let the moniker sway you. I started replying yesterday but did not want an opnion war so I initally erased it. I would lean twoard SPL as well and the Eminence will handle a beating better. I will be clear: Scans are NO slouch, but a pro woofer will do you well here. I have not modled myself, however some HIFI commercial offerings use to provide a lowish-tuned vented enclosure with a foam "port plug" to tube to tune to the room, etc. This is function of the driver and design, however I can see an advantage in this situation for such a design to get the bass extension for chillin', but having the punch and lack of unloading at high volumes when the party gets started. Just thinking out loud.
        .

        Comment


        • #5
          Re: Scanspeak or Eminence Woofer?

          Originally posted by Millstonemike View Post
          I was afraid that's where the collective wisdom would lean. That's not biased by your "handle" is it? -
          My handle aside, when you take sound outside you no longer have any walls and ceiling for reinforcement, so you need more output that you would for an indoor venue. 6dB difference between the two drivers is not insignificant. Another thing to consider is output per watt. Are you planning to power this rig with batteries? If so, the higher sensitivity driver will use less power for a given SPL, increasing your battery life.
          "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
          exactly a Fc 3K for both drivers, anybody can do it." -Xmax

          Comment


          • #6
            Re: Scanspeak or Eminence Woofer?

            Originally posted by dcibel View Post
            My handle aside, when you take sound outside you no longer have any walls and ceiling for reinforcement, so you need more output that you would for an indoor venue. 6dB difference between the two drivers is not insignificant. Another thing to consider is output per watt. Are you planning to power this rig with batteries? If so, the higher sensitivity driver will use less power for a given SPL, increasing your battery life.
            Yep, all factored into the design ... weight constraints, cab size constraints, weight of two SLA-AGMs needed to play up to 12 hours on single charge (1/2 the time at decent volume), full -6db baffle step as I expect zero reinforcement on the sand (4pi space) plus the rest of the stuff I learned (am still learning) from guys like you here at the forum.

            So in the absence of new info ... still the conundrum ... at 102db after -6db BSC, what is that like in a small venue outside. I want my low end extension and I need sufficient volume - cake and eat it too -

            I have a test bed: Peerless 830946 6.5" in .3ft^3 cab. It models with an F3 in the mid 40s and 103db w/o BSC. In my 400 ft^2 basement rec-room its loud enough. I need to test it outside, perhaps framing the box with a large baffle (4x8) to get an idea (but it cold out here in North Jersey).

            Comment


            • #7
              Re: Scanspeak or Eminence Woofer?

              How far away do you want to be heard? You lose 6dB for every doubling of distance. Also keep in mind that the 102dB that you speak of is probably peak output, not average music SPL. I'd figure you'd probably be good for 90dB music level @ 1m, and based on the size of the venue you can guess how loud it can be for your audience.
              "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
              exactly a Fc 3K for both drivers, anybody can do it." -Xmax

              Comment


              • #8
                Re: Scanspeak or Eminence Woofer?

                Originally posted by dcibel View Post
                How far away do you want to be heard? You lose 6dB for every doubling of distance. Also keep in mind that the 102dB that you speak of is probably peak output, not average music SPL. I'd figure you'd probably be good for 90dB music level @ 1m, and based on the size of the venue you can guess how loud it can be for your audience.
                I'm listening to you on the SPL. Just trying to see if the Scan Speak can do it.

                I mentioned I could perform a test outside with a Peerless 6.5" (830946) I have as a test bed. Its modeled and comes in at ~-6db less than the Scan Speak. Then I thought, what about the existing boom (Parrot Boom-box - actually 2.1 shelf unit). The 4.5" woofer blew so its replaced with a Peerless 830945 5.25" retrofitted into the box. That unit also models at ~6db less than the Scan Speak with an F3 at 62hz. So I now that sound on the beach and it's adequate but not fulfilling on the low end.

                Isn't it true that having more low end (16hz in this case) makes the unit appear louder?

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