Car speakers for Home Theater

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  • niksoley
    Junior Member
    • Jan 2014
    • 4

    Car speakers for Home Theater

    Hi all,

    I need help to setting up a subwoofer for home theater using speakers designed for cars

    Motivator
    High importation taxes in Brazil makes subwoofers price increase 3-5 times, a model that costs $ 800 in US can easily exceed $ 3,000 in Brazil.
    But in Brazil we have local factories for car audio, which reduces the price of some speakers to something fair to pay.

    Project
    Given this scenario, I'm thinking in mounting a subwoofer for my home theater using speakers originally designed for cars.

    Questions
    I have many questions on how to do this, especially considering the power supply, however, to structure thinking, I am seeking answer to the most basic question, which depending on the response can take my interest off the project.

    What I'm going to tell is difficult to explain in Portuguese, and for me, even harder in English, but the cars subwoofers that I known seem "dry", with "quick and superficial beats" and I do not like it.
    Follow examples of what I dislike http://www.youtube.com/watch?v=Q7pbfpBqyW4
    (Fonte principal): DVD Pioneer AVH-p4280(Ajuste Fino): Equalizador Pioneer DEQ-7600(Alimentação Estéreo): Amp. Banda 4.8 Performance(Alimentação Caixa Selada...

    Moreover, subwoofers designed for home theaters (mostly from good brands) have a deeper bass, it appears to involve the whole environment
    Here's an example of what I like : http://www.youtube.com/watch?v=qFHxTKNKaK0
    watching cloverfiled the bridge scene that hits hard and low did not use spl next time 9oclock on sub q at .3 1 port eq2


    It is not just a frequency vs SPL, given that there are subwoofer with the characteristics that I dislike that are capable of playing 20 to 200 hz with a very flat SPL.
    Also, it doesn't look to be the small space of the cars, considering that I saw some projects where people used car speakers for HT and had the same dry and quick beats in there big rooms.
    I wonder what creates this difference, and whether it would be possible to build a subwoofer for HT with the characteristics that I like using car audio speakers.

    Tks in advance.
  • ---k---
    Ultra Senior Member
    • Nov 2005
    • 5202

    #2
    Do you have the T/S parameters for the subwoofer drivers? These are industry standard measurements. Any tech data sheet? If you can get these, then we can help you model the box in Unibox or WinISD to find the right box size. Modelling will help you find the right compromise. The "Dry" bass you're describing is probably a low Q system. But usually low Q is different than extension. And some of it can be adjusted based on stuffing.

    Being a car subwoofer doesn't necessarily mean it will be bad. Usually they are just designed for smaller boxes and not to dig as deep because you get so much cabin gain in a car. We'll see once you get the T/S parameters.

    If you can't get the T/S parameters, then you would need to use something like a Woofer Tester from PE to measure it. or just experiment with trial and error.
    - Ryan

    CJD Ochocinco! ND140/BC25SC06 MTM & TM
    CJD Khanspires - A Dayton RS28/RS150/RS225 WMTMW
    CJD Khancenter - A Dayton RS28/RS150/RS180 WTMW Center

    Comment

    • niksoley
      Junior Member
      • Jan 2014
      • 4

      #3
      Hi K,

      Follow below the parameters of the Endurance E2K 15D 2, what do you think about it?


      Impedância 2+2 (ohms)
      Re 2
      Sensibilidade 88 (dB/W/m)
      Resp. Freq. 20 - 1,8 Khz*
      F0 30 (Hz)*
      Le 1.36 (mH)*
      BL 11.7 (T.M)
      SD 0,0804
      Qms 5.01*
      Qes 0.45*
      Qts 0.41*
      Vas 75 Litros*
      Mms 315 g
      Cms 45
      *Pot. Max/Nom. 1800/900 Watts*
      Xmax 12 mm

      There is 1 more brand, but I will need to search for specification, from measurements above, which are relevant?

      Thanks for the interest and quick response.

      Comment

      • ---k---
        Ultra Senior Member
        • Nov 2005
        • 5202

        #4
        That actually doesn't look too bad to me.
        It has been a long long time since I've done any subwoofer box modeling. So maybe I made a mistake. I highly recommend that if you have Excel, try modeling the box using Unibox.
        Jeff Bagby also has a really good driver modeling program that can even simulate room gain. It might be even better than Unibox, but I haven't used it.
        Both can be downloaded here: http://audio.claub.net/software.html

        Anyway, here is the graph I got:

        It's a 100L box, tuned to 27hz. The port is 15cm diameter at 59 cm long. The driver will exceed the xmax at 22 hz. That is a little higher than I like. So you might have problems with bottoming. A lot of plate amps have a high pass filter somewhere around 20 hz, so that might save it. With a 2ohm load, that is a tough load on a normal subwoofer plate amp. I think if you had two you could wire them in series to get that up to 4 ohm. You would then either need two 100L boxes or one big 200L box.

        There are probably other configurations. Maybe a sealed using bass boost from an plate amp. Jeff Bagby's program can model that too. So, I think there might be hope for you. Give the modeling programs a go and show us what you come up with.

        Also, what amps do you have access to / plan to use?

        And see if you can get any of those subs in a 4 ohm version.
        Attached Files
        - Ryan

        CJD Ochocinco! ND140/BC25SC06 MTM & TM
        CJD Khanspires - A Dayton RS28/RS150/RS225 WMTMW
        CJD Khancenter - A Dayton RS28/RS150/RS180 WTMW Center

        Comment

        • niksoley
          Junior Member
          • Jan 2014
          • 4

          #5
          Hi K,

          I will install parallels (I use mac) and star the simulations soon, but I need some time to read more about T/S parameters and so on, thats a lot of new stuff for me.

          Follow a table with 15 and 18" brazilians subwoofers:

          Brand Model Diameter (Polegadas) Z (Ohms) Pe (Wrms) dB SPL (dB/W/m) Fs (Hz) QTS Qms Qes Vas (L) Bl (T.M) Sd (cm2) Xmax (mm) Re (Ohms)
          Questo QS350A-15DVC 15 2x4 350 90.24 21.53 0.406 4.297 0.448 313.78 19.24 855.3 10 3.35
          Bomber SW15B-D 15 2x4 250 89 23 0.4 284 14.1 855 7 5.5
          Bomber SWBPN15-D4 15 2x4 550 89 23 0.54 210 21.6 830 11 2x3.2
          Bomber SWBP15EV800-D4 15 2x4 800 92 23 0.33 212 23.8 855 11 2x3.1
          Bomber SWBPE15-D4 15 2x4 650 90 24 0.51 223 17.2 855 8.5 2x2.8
          Bomber SWDUB15E400-D2 15 2x2 400 89 25 0.57 211 13.1 855 7.5 2x1.8
          Bomber SW15B-4 15 4 250 89 25 0.43 265 8.8 855 7 2.7
          Bomber SWBPN15-D2 15 2x2 550 91 27 0.36 145 19.1 830 7.5 2x1.7
          Bomber SWBPE15-D2 15 2x2 650 90 28 0.6 173 12.8 855 8.5 2x1.7
          Bomber SWDN15-D4 15 2x4 800 88 28 0.64 127 21.9 903 11 2x3.1
          Keybass 18 ECO 18 4 800 96.5 29 0.38 3.18 0.41 313 1150 6.5 3.6
          Bravox Endurance E2K 15D 2 15 2x2 900 88 30 0.41 5.01 0.45 75 11.7 804 12 2
          Bravox Endurance E2K 15D 4 15 2x4 900 87 30 0.52 4.14 0.59 74 13.5 804 14 3.6
          Keybass 18 TREME TERRA 4X4 18 2x4 1500 94 30 0.48 4.06 0.55 159.8 1150 12 3.2
          Keybass KSPA 18-1200 18 4 1200 96.5 30 0.27 9.14 0.28 236.5 1150 6.5 3.6
          Bomber SWBB18EV1500-D2 18 2x2 1500 89.9 31.2 0.48 10.8 0.5 100 1134 13 2.4
          Keybass 15 SUB 600 15 8 600 96 31.2 0.48 5.2 0.53 243 880 6 5.9
          Keybass 15 TREME TERRA 4X4 15 2x4 1000 94 32 0.38 3.88 0.42 102.7 880 12 3.2
          Bomber SWBB15EV1500-D2 15 2x2 1500 90.1 32.6 0.43 10.98 0.45 61.5 855 13 2.4
          Keybass KSPA 15-650 15 4 650 97 33 0.2 7.9 0.21 194 880 5.5 3.6
          Keybass 15 ECO 15 2x4 800 96.5 34 0.23 3.76 0.24 157 880 6.5 3.6
          Keybass KSPA 18-650 18 4 650 97 34 0.3 10.44 0.31 245 1150 5.5 3.6
          Keybass KSPA 15-1200 15 4 1200 96.5 35 0.28 9.47 0.29 154 880 6.5 3.6
          Selenium 15SW3P 15 8 800 95 36 0.31 13.7 0.32 132 23.9 814 6.75 5.7
          The SWBPN15-D4 from Bomber looks a good option for deep bass, low frequency, flat response and good timbre.
          What do you think, which one would you recommend?

          Comment

          • ---k---
            Ultra Senior Member
            • Nov 2005
            • 5202

            #6
            Good. Getting the software and obsessing over the models is 1/2 the fun. Unibox and Jeff B's software are just simple Excel spreadsheets (but need solver installed). So, if you have access to a work computer or computer lab with Windows or something, you might be able to get it to work.

            Do a little googling to get a better understanding of the different parameters.
            First thing I look at, and this is just me, is the Fs (or F0 it appears). This is an indicator of how low the driver will go. For Hometheater, the lower the better. Something in the low 20's is probably ideal, but you cold probably live with anything in the 20's.
            Next, look at the Vas. This will give you an idea of how big of a box you will need. The bigger the Vas the bigger the box. The SWBPN15-D4 with Vas= 210 is going to need a much bigger box than the Endurance E2K 15D 2. 210 L is getting pretty darn big. ...
            Xmax is how far the driver will move in and out. More Xmax = more potential loudness all else being equal.

            To use Unibox to model these drivers, you're going to need the Qms and Qes (the numbers missing from the table). Same with Jeff B's program. Not sure about WinISD. Hopefully, the supplier can get them to you.

            For the SWBPN15-D4, I like the lower Fs. You're going to need a big box for it.

            The SWDN15-D4 looks like it could be a good candidate too.

            Finally, I'm thinking that a lot of these are dual voice coils. So, if it has two 2ohm voice coils, you can wire them in series to make a 4ohm load that would be nice. If they have two 4ohm coils, you could can wire them in parallel for a 4ohm load that also works well. You should avoid a single 2ohm voice coil.

            Before you start running the models, I suggest you figure out how big of a box (or Tube) you can live with. If you're space limited, this could be a factor. A Sonotube sub might be good if you can get your hands on some Sonotube, like they use to pour concrete. Like 20" or bigger in diameter.
            - Ryan

            CJD Ochocinco! ND140/BC25SC06 MTM & TM
            CJD Khanspires - A Dayton RS28/RS150/RS225 WMTMW
            CJD Khancenter - A Dayton RS28/RS150/RS180 WTMW Center

            Comment

            • niksoley
              Junior Member
              • Jan 2014
              • 4

              #7
              Hello again,

              Due to high Vas, I decide to look for others drivers, and found 2 models of 10" that looks ok:

              Brand Model Diameter (Inches) Z (Ohms) Pe (Wrms) dB SPL (dB/W/m) Fs (Hz) QTS Qms Qes Vas (L) Bl (T.M) Sd (cm2) Xmax (mm) Re (Ohms)
              Bomber SW10-NewEdge400D2 10 2x2 400 83.27 27 0.75 5.282 0.874 59 8.2 360 11 2x1.6
              Questo QS350A-10DVC 10 2x4 350 87.8 24.85 0.289 3.462 0.315 81.33 18.66 380.13 10 2x3.75
              Mac has problems with excel macros, so I decide to install parallels.
              I decided to start with Winisd because it is more intuitive to simulate, but already have some doubts:
              1 - What are alignments in vented boxs (butterworth, boom-box, chebyshev, EBS -3, EBS -6)?
              2- What do you think of isobarik compound for my project?
              3 - Follow an image of a simulation using the sw10 model with EBS -3 and isobarik compound for reaching very low frequency with a 10" sub and with high qts. Do you think it is plausible?
              4 - What are the options to reduce the highest peak in order to harmonize the response?
              5 - How I calculate room gain?

              Still much to learn
              Attached Files

              Comment

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