Jump to content

duanebrow

Members
 View Profile  See their activity

  • Content Count

    188

  • Joined

  • Last visited

Posts posted by duanebrow

  4. Posted

    I modeled the band pass box in Hornresp. It is more advanced than WinISD. It came out about the same.... The biggest difference is that Hornresp said the box was about 8db more efficient! I think I might have messed up somewhere. But if not that would be awesome!

    I found out why Hornresp showed a higher db number. I was modeling in 1/8 space. (this is for corner loaded horns.) So the numbers were off.

    0

  5. Posted

    Even at 1500 watts 2x 11"x4.5" by 13.7" ports (tuning to 30 hz) you shouldn't have any noise or compression issues. Smaller sized ports would allow making a flange, making it easier to support changeable ports. I used the box volume of 15cf. I don't really trust the modeling software with this size of box - so I highly suggest making a removable port system. I did look at higher tuning, but unless your SW peaks at 50 hz it doesn't look like it will help much.

    0

  10. Posted

    Depends on the specs of the subs. You won't get near as much cabin gain in a house as your car. If you need to use what you have you need to be able to use software like WinISD to get a good FR for your house. If you want to step it up a bit more then you can use LIMP (part of ARTA) to measure T/S specs of the subs you have.

    0

  14. Posted

    In the WinISD graph it shows the front and rear chambers as 1.8ft^3 each, was this modeled for two subwoofers or one occupying that enclosure? I ask as if that was for one since would take up double the space available. I am at work and have no access to it right now.

    That is for 2. I have not tried to actually fit this design in a drawing. I think it could be a challenge to make the subs fit. I have found that splitting one of the chambers helps. (normally the ported one.) Then you can face the subs toward each other. This will need to be modeled to get the correct port size and tuning if you do.

    0

  18. Posted · Edited by Duane

    Down to 25Hz should be good. So the 29Hz dimensions would be good (15.5 x 2.75 x 24L). Would it be better to make a backwards capital L for the port or start at the lower rear wall and go towards the front, then back towards the rear to get the full length?

    The size could make noise at max output below ~33hz.

    I normally just make an L shape. I picked the size so that you can use the sides of the box as 3 sides of the port. (I have not done any calculations as to port displacement. So the length could be a bit off. It is modeled at 4.5cf net.) Here is what I modeled (I didn't include the 34 hz tuning)

    li12compare.jpg

    I added a 4th order band pass model also. Notice how it looks more like the sealed box than the ported. It should sound about the same also - just louder. Size is about the same as the ported box. If you want the specs on a bd type box just let me know.

    Please under stand that this is just a tool. These models are what the box will output while sitting outside. You will get louder in a car, but the gain is not a nice even thing. If you can measure the fr of your current box then you could see better how these designs would improve the sound... or not.

    0

  19. Posted

    I will check on the air speed @ 1700 watts. I don't think that it will be a big deal. Going with a 3" wide port will require about an extra 5" of port length. This should fit fine. Do you know how low you want to go? I was aiming at 30 Hz when I modeled the lower tuned box. It should be fine down to about 25 Hz. If you want to go lower, tuning should be lower.

    0

  21. Posted

    I'm on my phone, but that looks right. When you add cabin gain the sealed will be the flattest. But if you like that or ported is a matter of opinion. As far as the ported box I like the the lower tuned one better. If you will be listening to anything that goes down to 30 Hz I would go with that one.

    As far as the port area I used 1200 watts rms as the system power. With this much power the ports are big enough. If you go with a lot more power then you might get some port compression.

    0

  24. Posted · Edited by Duane

    http://www.incrimina...udio.com/li.htm I found T/S specs here. I don't know if they are correct. Is this the model you have?

    Ok that is old. I found them at SSA. Anyway 12x4 port would be about 31.5" long in a 3cf box. See if you can get move space after you subtract the port. That is plenty of port area if you are giving them 1200watts total.

    Also for the latest version of WinISD: http://www.facebook.com/WinISD

    0

  25. Posted

    Now you see why people just pay someone to design a box for them. Don't forget that you must subtract the port from the box volume. As far as port size/area it depends on how much air will be moving through the port. This will change with how much power is applied.

    I am a big fan of winISD, if you can list the specs you have for the drivers I will see what I can do to find the rest. Modeling the enclosure will show you how the tuning and box size will change your output. This can be directly compared to your current sealed box. I think this will go a long way to help you understand what is going on with the different enclosures. This will help you to be able to build better ones in the future.

    0
×