"MTG-08" 8" Celestion + DNA-150/DW-774s bookshelf/surround design

Discussion in 'Legacy Speaker Designs' started by Matt Grant, Jul 16, 2012.

  1. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Yep, passive crossover no need for anything extra, most of the time I run them off an old Yamaha 65w/channel recevier.
  2. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Any chance of seeing a shot of the finished crossover? just to help with component layout....
  3. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Mine may not be the best example becuase I used parts I had on hand and re-used an older board, also not the greatest picture.

    The larger air core you see on mine should be the 1 mH solid core and the small one is the the 0.6 mH air core. Then I have two capacitors in there on the woofer to get the correct value and also the two resistors 5w 10 ohm and 10w 2.2 ohm = the parallel 1.8 ohm on the tweeter as well.

    I plan on picking up the correct parts soon and will rebuild the board which will make for a better example.
  4. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I got all the correct parts and rebuilt the crossovers on new boards. They are nice and pretty now, too bad you won't be able to see them in the speakers.
    Edit: The board measures 5.25" x 6.75" for those interested.

  5. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    for those that don't have much experience reading a circuit diagram a picture like the one Paul provided on his OS MTM page is a real life saver, you can see it here on the right https://sites.google.com/site/undefinition/overnightsensationmtm

    helped me a lot when i built mine as i hadn't looked at a circuit diagram in ~15 years
  6. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    That is a good idea sibuna, so here is one for those who have trouble with the circuit diagrams.

    Input is on left, woofer out top left, tweeter out top right.

  7. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    That IS a lot easier to understand.
    Where did you get the terminals? I assume those would make it easy to (un)hook to the drivers and amp.
  8. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I'm glad you like it. :)
    Those terminal blocks are at PE on clearance for quite a decent price: http://www.parts-express.com/pe/showdetl.cfm?partnumber=099-102
    They do make it easier to disconnect or change out wires going to the crossover but I still use regular disconnects on the other ends to attach the wire to the drivers.
  9. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Thank you so much for the wire routing of the crossover..I did notice that it appears you used a 10uf cap instead of the 8uf listed in the parts list...is it ok to use the 8? because it's what I have at the moment..
  10. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Oops, ;D
    Only makes a 0.5dB difference around 800-1200hz, the 8uF is the correct part.
  11. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I have seen the light!
    Never again will I use the rattle can for speakers and the roller will see far less use here on out.
    Spraying latex is where it is at.

    I had these sitting with primer (also sprayed) on them for a while but need to hurry up and finish them so I can start on the new stuff. ;)
    Sprayed the paint on these tonight during sunset so it got pretty hard to see. Had some spots I missed and others where I had a little bit of running (might have thinned it a little too much). I am going to put a second coat on so its not really a big deal. Once that is on they will get some water based clear and then comes the hard work.


    $16 spray gun from menards and Rustoleum semi-gloss latex paint. I used about 1/4 of a quart to cover these.
  12. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    They look pretty darn good right now.

    I hope you go into more details about that painting method. Heck, for the price of the gun, you could paint a bunch of speakers, then not even worry about cleaning the gun out. Could that be done in a small temporary room set up in the garage or shop? Or would you still be sucking junk into your lungs?

    I need to figure out an easy way to finish some boxes if there ever comes a time to assemble and paint some of the better designs.
  13. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Very nice MTG. Ya, spraying is by far the best way to go. I have an airless wagnor jobby that I use for heavy paints like flat black and a HVLP gun for polys and what not. Both are well worth it.

    Erich, you sure could. Wear a mask though. A good one. Eye protection is a good idea also if the area is small. Pain though. And be mindful that overspray goes everywhere, so make sure there isn't anything around that can't be painted. Like your shop floor if you care. Lay down drop cloths or what ever to protect your surroundings. It takes a few tries to get the nack, at least for me it did.
  14. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I should note that the gun is $22 from menards, I was thinking of the one I was going to get from HF for $16 but was out stock. Stopped at menards on my way home and they had this one.

    I'll try to get more details on the whole process when I paint the MTG-06's that could be really soon. Since the semi gloss looked so good I think that is what those will get. For these I'll try and get some pictures of the process for second coat and the clear. Of course the sanding and polishing is something I am not looking foward to.

    At first I applied alot of primer with the roller but got too much texture and had to sand most of it off. Then I sprayed it and the primer did not go on nearly as nice as the black did. I think it dried too fast. You could handle them in 15 min after you put the primer on. Anyway spraying was still better then the roller, you will see that step for the MTG-06.

    There still is some overspray that will cloud up a small temp paint booth so you need some good ventalation. Odor is almost non-existent compaired to rattle can or automotive paints so I don't think it is as bad for health. Still were a good respirator though. Cleaning the gun is simple since the latex is water cleaup. Rinse the can out with water then put some clean water in there and spray the water through the gun to clean insides. Then empty water out and just spray some air through it to clear out any water so it does not rust. Only takes two minutes.
  15. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I put another coat of black on these today. Here is my painting booth:


    I thinned the latex a little with water I am not 100% sure what ratio I used but it was close to 8 oz of paint with maybe 1/2 oz of water.
    I should have thinned before running it through the filter because it took forever for that thick latex to make its way through.
    A little messy, but paint in the gun and ready to go:

    I did not get any pictures while painting but what I did was adjust pressure on the regulator I have mounted on the gun to 40psi and adjusted the paint mixture while testing on a scrap piece until I thought it looked good then started painting.

    Here is what they looked like when I brought them in to dry.

  16. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Sweet paint booth!

    I'm sold on the $22 gun and latex. If you went with that super high gloss kitchen/bath paint, do you think you would even need a gloss coat? That's some pretty durable paint and has a good shine to it.

    I need to clear out an area at the shop for this.
  17. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    If you got the primer coat real smooth I bet you could get a good shine with just that paint.

    I had to put the drivers in it to see what it would look like:
  18. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    You just discovered the secret to finishing. There is nothing more important than proper prep work. Whether that means grain filling with epoxy or multiple build coats, or in this case, primer, a good prep will make everything better.

    Terrific find on the rust oleum. Looks like a great way to get a finish inexpensively.

  19. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I like the look of the semi-gloss so much that I think I'll keep them this way. I can always put a clear coat on at a later time. They would just need a light sanding and another light coat of black then the clear.

  20. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I would, too. Dang, those look nice. See, Erich, - shelf ports!
  21. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    ??? Freaking nice man !!!
  22. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Thanks guys, they still bring a smile to my face when I look at them.
  23. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Hi to all. First post in this forum. I felt the need to read as much about all of this before I posted. Yes the anybody want flat packs to the lets design a replacement wave guide (that’s a long One!). Maybe not the place for it but THANK you to so many for their efforts. Epically Eric. Now for something relevant to this particular part of the Forum.

    MTg90. Fabulas build. The clarity of the you tube video sold me. So much so I bought and received The MTG-08 kit. Nice kit I must add. So simple a cave man can do it. My question is: what is your recommendation for fill. My usual in a box of this type is 2.0" Fiberglass covered in .5 to 1.0" Dacron sheet to kill the floating glass bits, especially in a ported design like this one (don't want the grandbabies sucking in bits of fiber glass as they breath) and to make sure to give the ports some space. What is your recommendation?
    Thank you. Roger

    PS nice finish. You have got me thinking of going to Harbor Fright and buying a low cost gun....
  24. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Hi Roger, and thank you.
    The fiberglass/darcon should work fine, make sure there is an opening from the woofer to the ports and your all set. Personally I moved away from fiberglass a while ago, right now I am using denim insluation which is much nicer to work with.
  25. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Thank you for the fast reply. I just in the past few days started to see the denim usage. Do you find it as efficient as the fiberglass? Unfortunately it is still mail order in my area.Fiber glass didnt bother me much. Long sleeves are a must though. Now off to Home depot and the craft store. I will post my listening impressions when I get them finished. However I have a long Honey do list... (don’t we all) Is that a DIY dust filter on your shop Vac. exhaust?

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