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

Discussion in 'Home Theater Speaker Kit Information' started by Matt Grant, Jul 16, 2012.

  1. Just to be clear there are now only 6 components to the newest crossover?

    I will be building mine soon. Erich said he may have some 774 WG's but needs to check. I have JBL 8" WG's that I will use for now. Not ideal but I want to get something started soon. And when Erich states he does have the WG's I will be buying 3.

    Cant wait to get started.
     
  2. Just got my waveguides today. :D Buying the crossover parts today and hopefully trying to make a jig for WG. Will be making four of them so I want to make a jig to make things easier. That 2.5mH air core seems to be more expensive than I thought. Will look and see if I can find something locally for cheap. BUT when I looked at the website I was ordering my caps from they only has 2.5mH 15AWG for 33 dollars each. So that is going to get pretty expensive quickly.

    I found 2.7mH for less money. They seem to have more variety of the 2.7mH air cores than 2.5mH.
     
  3. Buy the 2.7mH and take a few wraps off ;)
     
  4. Ya thats what I planned on doing. Just figured it would have been an easy find and it wasnt. Oh well. Time to get some MDF
     
  5. Having just purchased a pair of the Celestion TF0818s for a great price ($35 each at MCM electronics), I'm getting ready to order the rest of the parts needed to build a pair of MTG-08s. But for the crossover, I'm not certain if I should go with the earlier design, with the 3rd order on the woofer and second order on the tweeter (schematic V1.11 7-26-2012), or with the newest crossover with a second order on the woofer, and first on the tweeter (schematic V3.1 8-8-2014). You (mtg90) answered a question earlier in this forum (from killa on 11/02/2012) about your reasoning in selecting the 1900 Hz crossover frequency, and how you preferred the sound of the system with that crossover point. But your latest crossover, while elegant in its simplicity, appears to be a textbook 2nd order Linkwitz-Riley at 1 Khz for the woofer, which would require to tweeter to crossover lower as well. With the newer crossover, I did see a fairly big dip centered around 3800 Hz, though you mentioned that you had later changed the padding slightly for the tweeter. Still, the posted frequency response of the earlier crossover seems a bit flatter to me. Graphs aside, do you favor the sound of the later crossover design? Certainly it's attractive with the lower parts count.

    Thanks.
     
  6. It may appear textbook, but loudspeaker drivers don't have textbook flat frequency response and impedance profiles, acoustic crossover is still ~1850 Hz. This is currently the latest and greatest crossover which I built and tested over the weekend, some minor adjustments one of which is to help fill in that dip between 3-4000 Hz. I do believe it is superior to the earlier crossover designs.

    [​IMG]
     
  7. Wow......I was just getting ready to order my parts for four of these XO builds and then I saw you made a revision. Thank god I looked.

    I can only find a 12ohm resistor and then 22 or 27. Will have to order from PE for these resistors. :( More time to wait.
     
  8. You could place two or more in series or parallel to get 25 ohms if you don't have the exact value.
     
  9. I'm eager to get started on my MTG-08 build, but the DIY Sound Group has been out of stock of the [SIZE=small]DNA-150s, and Erich tells me that it will be at least [/SIZE][SIZE=small]two months until more are available for individual sale (outside of kits). While I realize that the current design is has been highly optimized using the Celestion + DNA-150, I have to ask if there's a (readily available) substitute compression driver that might work well in your design.

    Thanks!
    [/SIZE]
     
  10. I don't know if there is anything that would be a drop in substitute, the Celestion CDX1-1010 might work with some minor adjustments to the crossover but without testing it I can't be sure.
     
  11. I'm going to try to bring this kit back in some form eventually. Right now I'm trying to get the site organized better then will focus on some of the other designs. Back when the MTG-08 came out very few people were wanting a speaker priced that cheap because they assumed it wouldn't be very good. Of course they were wrong, but it just wasn't working out trying to keep all the stuff in stock for some speakers.
     

  12. Thank you Erich! :)
     
  13. mtg90, MTG-08 vs Fusion 8. In your opinion, is one superior to the other? What about the Alpha Minion? Would appreciate your input and advice. Thanks!
     
  14. Fusion-8 is likely better then this design using a better CD (205 vs 150). The Alpha-8 uses a nicer woofer then the Fusion-8 so I expect that to be superior to the Fusion-8.

    MTG-08<Fusion-8<Alpha-8
     

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