Budget speakers design ideas?

Discussion in 'Home Theater Projects' started by Ryan T, Aug 4, 2004.

  1. Ryan T

    Ryan T Second Unit

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    Well I've had a pair of PE buyout woofers laying around for a while and I finally decided to build a set of budget DIY speakers with them. I wanted to do a kinda unique design with the speakers though. Heres the drivers i'm gonna be using

    http://www.partsexpress.com/pe/showd...number=299-432
    http://www.partsexpress.com/pe/showd...number=297-409

    I still havnt received the tweeters. They were supposed to ship the 1st but they are delayed untill the 18th :/. So i'm not sure exactly how they mount too the enclosure. I guess i'll find out when i get them. Anyway I want to put the JBL midbass in a sono tube thats 5" dia and about 7" long. Then mount the tweeter on the top of the tube. So the 5" tube would be laying on its side with the midbass in one endcap then the tweeter right on top of the tube.

    The problem I ran into is I cant seem to find any 5" sono tube so I might be forced to use PVC pipe. I just dont know if PVC is gonna be too resonant and end up sounding like crap. As to the crossover i'm just going really simple. Gonna try an unoptimized linkwitz 2nd order at 2,300 Hz and a 1st order at 5000 hz. I'm gonna see which one I like better. I realize that to build a good passive crossover you need a lot of equipment and some design programs but that kinda blows my budget outta the water. I wanna see how good I can get these to sound just using basic crossover calculators.

    Mainly i'm just wondering if anyone has any ideas about a 5" dia tube that wouldnt be suitable for a speaker enclosure. Im always open for other suggestions too regarding my design [​IMG]. I havnt ruled out just building standard MDF boxes for the midbasses but I think the tube idea would look really cool if it works. And its much easier to just cut endcaps then build a good box with the tool I have [​IMG].




    Ryan
     
  2. Owen Bartley

    Owen Bartley Second Unit

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    Ryan, that sounds like a really cool idea, I hope you take pics of the process!

    Also, I just had an idea when looking at the tweeter. You could try to round the back end cap of the woofer enclosure to match, that might look pretty solid. Not sure how, just thought it would look cool.

    Keep us updated!
     
  3. Ryan T

    Ryan T Second Unit

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    Well heres my idea for the back end cap. I didnt say anything before because I dont know how easy this is. But they sell this modeling foam that you can sand and mold preatty easy. I was going to sink the back endcap in about 1/2" so the sono tube would stick out past the cap. Then try to mold a cone shape out of the foam and cover it with black speaker grill fabric then attatch it to the back. I was thinking of making the tube 5"~7" deep with out the cone. Or If I can smash that mid bass and a crossover in a shorter tube I wanted to only make it 3 1/2" deep (with the front endcap it would be about 3") with the cone extending it to about 7" total. I'll just have to see how easy it is to mold this stuff. Maybe i'll luck out and find a fence post cap or something that is rounded and the right dia.


    Ryan
     
  4. Ryan T

    Ryan T Second Unit

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    Well I just got an e-mail back from PE and it looks like the tweeters wont be in stock untill around the 27th [​IMG]. So I guess my project is going to be delayed a bit. Anyway once I get the tweeters I will be sure to take lots of pics of the building process!



    Ryan
     
  5. Joey Skinner

    Joey Skinner Second Unit

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    You might find a 5" cardboard tube or something close at a carpet store.
     
  6. NickSo

    NickSo Producer

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    Have you checked out home depot? They have a bunch of smallersized sonotubes.
     
  7. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    I did similar projects for my car using fiberglass enclosures and separate mounted tweeters.

    I used the $15 Tag band Neodymium tweeter along with the 7" buyout PE infinity woofer that I think they sold out of.

    I also have those exact 4.5" JBL drivers, but I havn't used them yet.

    I tried out the Buyout Vifa Classic 1" Titanium dome tweeters in my car and I blasted them pretty loud for about 5-6 months. Then one hot day playing loud rock music, one tweeter decided to blow out... I then did a direct swap using the Tag Band tweeters because the specs are very similar and everyone that listens to them like the sound of the soft domes much better. The 7" vifa has a good amount of bass from them in my sealed 4-5L box.

    If I remember correctly, I tuned the crossover to have more of a laid back sound giving the highs 3000hz and above, and the woofer 2000hz and below using a 2nd order LW XO. I also put an attenuator circuit on the tweeter to reduce the volume a bit. (And I threw in a Zobel in there for reasons I forgot)

    The 4.5" JBL I expect to have little to no bass at all, and was going to see if I could put them in the dash of my 4runner. (Because the factory size of the speakers in the front are 4"). I was under the impression that the 4.5" JBL is supposed to be like the "mid" driver in JBL 3-way designs. (Focusing on vocals and not bass)

    Anyways, GL.

    I calculated the volume needed for those JBLs is about the size of a small coffee can... Tiny little guys.
     
  8. Ryan T

    Ryan T Second Unit

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    I just called a lot of local stores and nobody makes 5" dia anything :/. I think I might try some carpet stores we'll have to see though. I'm thinking about making 5 MDF rings that are 5" dia (outside) being 1/2" think. they would be made out of 3/4" MDF and glued together. If i cut them 1/2" thick they should leave 4" internal dia and thats just enough for the JBL. It might be more work than its worth though. I still dont know how that tweeter attaches to the enclosure so I cant really make any design final until I find out how to mount the tweeter. Which is proally gonna take about 3 weeks when I fianlly get mine in :/.

    I did try the JBL's in a small 6"x10"x7" box and there sure wasnt much bass. But there only 4" midbasses so you cant expect much. I think WinISD said there F3 in my little tube enclosure is gonna be 150~ Hz. Not exactly as low as i would want them to be but for the size of the speakers it isnt too bad I guess.

    I have a left over 10" titanic 1000 that i'm gonna use with them. It has OK upper bass response so i'll just have to see if it can take over from 160 Hz and down. If it really doesnt sound good i'm considering useing the same tweeter and just jumping to this midbass and pulling the Xover down a bit to around 3000 Hz or so.

    http://www.partsexpress.com/pe/showd...number=299-493

    It looks to be a pretty decent and the price isnt too bad [​IMG]. I would just try and use a 8" sono tube from Homedepot which would make my life a whole lot easier [​IMG].



    Ryan
     
  9. Ryan T

    Ryan T Second Unit

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    Ok guys its been a while since I updated this but heres my progress so far. After testing the midbasses out I decided that I wanted to do either a MTM or TMM with these midbasses

    http://www.partsexpress.com/pe/showd...number=299-433

    They come out to about the same impedance wired together and the FR is just as good. Anyway I got the 6" PVC pipe yesterday and I cut and glued the front baffle today. I'm gonna port each enclosure so the F3 should be about 75 Hz. The tweeter is gonna go in the middle but i'll have to cut a bit outta each PVC pipe for it to fit. I cant do much more untill I get those dang tweeters. There supposed to be in stock on the 20th now so if thats ture I should be getting them sometime next week. I'm gonna try and cut the rear baffle tomorrow. Anyway that kinda gives you an idea how the speakers are gonna be shaped. I'm still torn between using just textured black or red maple PE laminate. I think it would look cool to use the red maple and make the PVC look like wood [​IMG].


    Ryan
     
  10. Allen Ross

    Allen Ross Supporting Actor

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    how do you wire them together to get the same impedance, or do you mean DCR?
     
  11. Ryan T

    Ryan T Second Unit

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  12. Ryan T

    Ryan T Second Unit

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    Hey guys.

    i finally got the tweeters in today! After messing around with them I decided to scrap the MTM for now. It would invlove cutting into the PVC then resealing it. Just seemed like too much of a hassle. I might try it sometime later but for now I'm just sticking with the original TM design.

    Heres some a of the prototypes I made today.
    [​IMG]

    It took me a little bit to figure out how to mount the tweeters. The tweeter mounts have 2 holes for screws and 1 for the lead wires. I couldnt use the front screw hole cause the MDF end cap is too far into the PVC. So I have to make do with just the one screw for now. If I recut the front endcaps I'm gonna use only one peice of MDF like for the rear and use my Dremel router to cut a little recess on the edge. I think I like the 2nd order 2,300 Hz crossver better. The 1st order 5,000 Hz sounds a little to dark and the treble is kinda tizzy sounding. The only problem with the 2nd order is the tweeter seems to over power the mid bass a little bit. So I'm gonna pad the tweeter down 1 dB and see if that fixes it.

    So far I'm VERY happy with them though. Aside from being a little bit bright they sound very good. I know the midbass in the middle of the round baffle isnt very good for baffle step but there gonna be fairly close to the rea wall so I'm not to worried about that. I'm still thinking of porting them. It should bring the F3 down from 150 Hz (sealed) to about 70 Hz. Which would help a whole lot with crossing over to my 10" titanic subwoofer.

    Once i get all the crossover stuff worted out i'm gonna sand and smooth the enclosures out and laminate them so they dont look so dang ugly [​IMG].

    Ryan
     
  13. NickSo

    NickSo Producer

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  14. Ryan T

    Ryan T Second Unit

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    Thanks [​IMG]. I'm toying around with shortening the PVC. What I really wanted to do was have a much shorter PVC pipe (3~4") and make a foam cone the same shape as the tweeter. Then attatch that to the back endcap. I think it would look really cool if the woofer enclosure matched the tweeter. But I think its gonn be VERY hard to make two cones outta foam that match each other and the tweeter.


    Ryan
     

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