Announcement

Collapse
No announcement yet.

Another 3-way... Is it a monkey coffin?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • rpb
    replied
    Originally posted by davidB View Post
    Raise the cross to 7-800hz, and use zobel(s) to reduce coil needs, esp. on the woofer.
    Maybe switch to a 4 ohm mid?
    I prefer to cross at 400hz. I played some more with PCD, and I believe that this combination could work. I don't know why I had so much trouble before with the sim. The 2mH coils I thought I'd need to buy, are likely in my parts box. These are for the mid highpass. My parts are buried under some other stuff in my closet. My back, and neck are sore today, so I really don't want to move a bunch of stuff to look. Also, it's just too hot to do any building outside.

    I remembered that I have a pair of RS125p drivers. They are 8 ohm, but have a wonky response above 1k, like the graph for the 4 ohm version shows. I was able to get a couple dB of gain in the x-over sim. These could be used, but would likely need to cross under 2k due to the response. The RS would look better than the 6.5" Peerless, but the Peerless could play a bit louder.

    Leave a comment:


  • davidB
    replied
    Raise the cross to 7-800hz, and use zobel(s) to reduce coil needs, esp. on the woofer.
    Maybe switch to a 4 ohm mid?

    Leave a comment:


  • rpb
    replied
    After playing around with the mid x-over in PCD, I see that I would likely need to buy some large coils, which is not an option for me right now. So...This project is on hold, and might not be pursued at all. I thought it would be easier, but an hour of PCD just made my head hurt!

    Leave a comment:


  • djg
    replied
    Widebody?

    https://sites.google.com/view/sehlin...tions/indium-7

    Leave a comment:


  • Serenitynow
    replied
    Originally posted by rpb View Post
    Turns out that 1.6 cu-ft gives a nice response with an f3 in the low 30s.
    If you make them 38" tall x 11.5" wide, that only leaves you about 9.5" of depth. This doesn't account for driver or bracing volume tho.

    Leave a comment:


  • rpb
    replied
    Turns out that 1.6 cu-ft gives a nice response with an f3 in the low 30s.

    Leave a comment:


  • Serenitynow
    replied
    Just remember about enclosure size if you're worried about appearance, if you add depth to them to gain volume, YOU CAN'T SEE IT FROM YOUR LISTENING POSITION 👍👍👍
    The frontal area stays the same. Just something to think about.

    Leave a comment:


  • rpb
    started a topic Another 3-way... Is it a monkey coffin?

    Another 3-way... Is it a monkey coffin?

    I've had the bug to build something for quite a while. Recent threads have steered me towards a 3-way. My current 2-way speakers are around 81dB at 2.83v. I hope to be over 85dB with this design. My desire for the extra sensitivity is fueled by the equipment that I want to use. With this equipment, the volume knob has to be past the one o'clock position to get the level I want. Sometimes just past the 3 o.clock position. The output voltage of the CD player seems to be a bit lower than ideal. The sound quality is good though, and the knob position really doesn't bother me all that much. It just looks wrong.. The receiver is an Outlaw. It can drive pretty much any load within reason, and has lots of power. A friend brought over a 50 disc CD player that he bought used. We hooked it up, but I told him to turn down the volume knob before starting a disc. It was probably 6dB louder, or more.

    The speakers will be used in my living room, which is roughly 13' x 17' I think. Room furnishings are mostly a couch, area rug, and the audio system.

    Woodworking is not my thing, so these speakers will at best be painted a flat gray or some neutral color.

    For drivers, I want to use mostly the ones I have already. The current plan is to use the Dayton RS270P-4 for the woofer. It's 91dB at 100hz. That should result in a speaker that is about 5 dB less, so around 86 to 88dB depending on how much BSC I end up with. I have not yet decided on bass alignment. Sealed doesn't look that impressive on paper, but I like a low Q roll off.

    The mid will most likely be a 6.5" Peerless 830874.It's right at 87dB sensitivity, and a relatively easy driver to work with. I've used it in 2-ways crossed as high as 4k, although, that was just to see what it would sound like, and not used for very long. I hope to keep the x-over part count reasonable. Previous 3-way attempts got up over 30 parts I think.

    The tweeter is unknown at this point. I have several that should work well. I just need to decide.

    The x-over. This is my favorite part of a build. I mostly do things by trial and error. I do measure, but I don't sim much of the design. I have some sims from a while back for the 830874, so, I'll probably sim that, and then make adjustments. My xo points will most likely be 400hz, and 2.5k. I have a good supply of xo parts on hand, but I will not be buying any more if possible, so the woofer to mid xo point will depend on parts on hand.

    Baffle width. I don't know how a wide baffle will affect the sound quality. Maybe someone who was involved in the Indiana contest will have some comments.

    Size. I think that I'm OK with a pair of 3 cu-ft boxes in the room, but I could be wrong in the long run. Also, I'm already dreading handling heavy speakers during construction.

    Height. I think that for appearance reasons, I may limit the height to 38".

    Comments are welcome. I will post details along the way. I will start with some sims of the woofer, and mid for an approximation of xo part values that may be required.

    PE measurements for the 6.5" mid. https://www.parts-express.com/pedocs...spec-sheet.pdf
Working...
X