"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

    Very nice MTG . Now I need a gun :)
  2. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I am pretty sure the denim is up there with fiberglass for effectiveness. Fiberglass is fine when you only have to put it in there once, but when your pulling it out and putting it back a few times during the design process denim has its advantages. After I switched from fiberglass and before I went to denim I used foam carpet pad with darcon or poly batting over it which was perfectly fine. I switched to denim when I figured out it was cheaper in the long run, one $50 bag of batting should last me almost forever. :)

    It is a DIY dust filter, I threw that together one day becuase I was bored. I don't think it works anywhere near as well as a duct deputy or other cyclonic seperators but it does OK. Some fine dust like MDF still makes it through but I don't need to clean out the filter on the vacuum nearly as much. I will modify it at some point and post the design if it works better.

    Thank you, spraying is definitely worth it.
  3. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Wow, those look really good. Very impressive. No doubt I'm going to set up a little room at my shop strictly for painting the latex.
  4. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I'm making my first post to give a mini review of the kit I ordered. First of all, they arrived in excellent condition. Very well packaged, the way they're packaged they would be able to withstand a lot of abuse in shipping.

    Assembling the speaker cabinets was a piece of cake. Every piece had a clear position without the need for notes or instructions. I assembled the first one using only glue with painters tape holding it together. I ended up using brads on the second.
    I had some confusion with the crossover, I've never assembled one from scratch. I had to get some help interpreting the schematic, once I got the order figured out I managed to clumsily solder everything together and I made the mistake of soldering the crossover components together before I placed them on the board, so the component position probably isn't ideal.

    I haven't finished the cabinets yet, I'm still undecided on the finish I want. I'll probably end up going with a matte/semi gloss finish. I really believe that looks great. I'm pretty decent at body work, so a bit of sanding and filler will be no problem. I've got some good urethane 2k primer to spray on, then some of that latex paint. I'm interested to try that latex, looks interesting.

    With that all said, they sound amazing, I'm very happy and surprised with the way they came out. I believe "clear" is the best way to describe them. I love the way that DNA-150 pairs with the waveguide. I'm also impressed with how loud they will get without any sign of strain. The low end is a little lacking and I expected it. They have great punch and impact, but they fall flat when asked to play low. I'm completely fine with that, since they are begging to be matched with a good sub.

    I have a few photos I took when building them. I also have them in a VERY temporary setup. To help reference the size of them, that's a 30in monitor in the picture. I have them running in just stereo mode on a Pioneer vsx-522, about 80w rms. Eventually I want to build/buy some speaker stands and drop the crappy 5.1. It turns out I always leave in it stereo mode anyway.

    Placing them upside isn't a bad thing is it? Since I don't have stands yet I placed them like that to make the tweeter be closer to ear level when I'm sitting.
  5. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Woohoo first review. :) Thanks gadkins.
    Really glad you like them.

    Placing them upside-down only causes problems when it puts the tweeter close to a reflective surface out in front like the shelf on the left side. Close reflections like that are worse for the high freqencies then the low freqencies which is why you usually see the tweeter on top. However being off axis is probably worse then the little bit of reflection you might get.
  6. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Gadkins. Well now you have gone and shamed me... (LOL) I better do my review (tonight from work, its time to go now). Your build looks good. I agree, if I could only use one word it would either be "clear" or articulate. Congratulations on figuring out the soldering thing. Can be a big deal, at first. Seems however you nailed it pretty well. I found that my bass was pretty good however. No, not all the way down to the basement, but enough for jazz. ( bad play on words..."close enough for Jazz)I did however notice the spiders on the celestions were very stiff. I think most all pro woofers are. So I gave mine three days of 20 kHz. break in. So I am betting yours will only get better. Sure a subwoofer is still needed, but I listened to mine for a wile without them and was pretty pleased. Now where is my spray gun? Oh yea, still on the shelf at Harbor Freight! And Big Kudos to the designer.
  7. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    These Horns Don’t Honk
    (Caution, lots of wind and opinions ahead.)
    How does one start a proper review? Lord knows we have read enough of them. Let me start by saying that I understand that in some circles Klipsch is nearly as bad a word as Bose. I however have a fondness for some of them. In fact my home theater has KLF-20’s with matching center and Klipsch rears. Still able to do a very good job. These horns do not make ears bleed like the older K’s can. I picked up the MTG-08 Speaker kit after seeing the you tube video that the designer recommended to look at. I was stunned by the clarity. I knew, it was a gamble because there is no reference standard for the internet. However the sound was just so clear, and at the price… I took the gamble,plus after reading so much of the things Eric was involved in I had developed some trust of his opinion, even though I had never met the man.
    I admit that older style horns have some bad habits, epically at high wattages. They were however developed to make use of small wattage tube amps and can still do pretty good music when used that way. However, crank them and words like, honk, fatigue and even pain can be very fitting. Even the new term HOM’s can be seen ( even more so) in the older metal bells. So my K horns and La Scallas are played low and with Tubes. However there seems to be a new breed of horn now that has mitigated many of the old problems. So if you have a bad taste from the old horn sound, give these a try.
    Over my lifetime I have built my share of DIY stereo stuff. Many tube amps and several speakers. The best speaker I have built was Adire audios Bang(as in Bang for the Buck) and now these MTG-08’s offer even better Bang, with just a bit less base. I also admit to some fostex designs (that I will keep) being played through a 300B amp. However If I had to re- buy five to seven speakers for home theater/ music, these would be they. Especially if WAF and funds were of concern (when did sevn times $140.00 become low cost?). I have owned and heard many different speaker systems. I only keep the good ones. These will be keepers.
    What I have noticed with these is the lack of Honk and the clarity. That little 15.00 driver is amazing. Even when played at peaks of 100 Watt True RMS and a sand amp at that ( to the speaker as a whole, not just the compression driver). I also noticed small things like: Melody Bardot’s who will comfort me? There is a wind sound as she starts the word “Who”, or a drum stick makes a tick sound just ahead of the shimmer of the brass, or that a Rim Shot has wooden overtones mixed within it. I have long enjoyed the vibraphone but with these there is more tone and harmonics within the resonating woods of that instrument
    In short. Fine sounding, high value. It takes (IMO) at least a grand (commercially) to best these above70- 80 Hrtz. Easy build, and like it says on the web site…”speaker is designed to perform best when crossed over to a subwoofer around 80hz, but can be used full range when called upon.” Good value. Good sound. Good stuff. Thank you MTG90 for the design.
    A short word about the wood and the “Kit”: All parts as needed for x-over and good value. Precision cuts to the wood. Intuitive and easy assembly. Thank you Eric.
  8. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    oh... Break in was done at 20 HZ not KHZ
  9. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Thanks Roger,
    I am happy just to have contributed and without Erich none of this would have been possible.
  10. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Wow Roger, very well said review.

    When I started research for a new set of speakers, I decided ahead of time that I wanted something with a horn driver. I didn't have a real reason, I just got it in my head that's what I wanted. Of course I looked at the various "econowave" builds but I was worried that I wouldn’t be up to the challenge of building a set of those. That's when I started to look at the MGT-08 kit harder and harder. The size was right, they are affordable, and I really like the way they look. The additional benefit was the fact that the panels were precut. My initial hesitation was because I've never heard of this website, the same goes for the designer (no offense intended), and the drivers used in the kit don't have any real feedback. This thread and several posts over at the partsexpress.com forum regarding other kits (the hitmakers and the Overnight sensation mainly) helped persuade me to order. I sure am glad I did. As for WAF my girlfriend thinks they are ghastly looking, it's all good since we don't live together (yet). Even she has to admit, they are quote: "nice sounding"

    I have a couple of observations about their placement in my game room/office. The bass these speakers make isn't lifeless, the issue is my seating position is in a null spot in the room. I'm still trying to understand the room interaction, if I move about 4 ft back from normal the bass fills out and is quite impressive, which ironically is nearly the exact center of the room. I think what I might do is rearrange and try to leave some space in front of the desk to place the speakers.
    I hope to build stands for them this weekend.
  11. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I should be getting these soon and was just a little curious as to why you chose your xo point of 1900khz? It is usually better for power response to cross lower due to a larger ctc distance of a 8" woofer. Is the tweeter not capable of crossing much lower? Not trying to call out your credibility as you appear very capable. I guess I am just curious as I have never used a compression driver or wave guide before. I will probably measure these myself and play with them just to get a little experience with waveguides and compression drivers. I am a tinkerer by nature and can never leave anything as is lol.
  12. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    I could have pushed the crossover lower but I was trying to keep the crossover at a point were it would maintain some control over horizontal directivity. The waveguide starts to lose it at about 3.5k so the pattern widens some below that before the woofer pulls it back in. A lower crossover point would just make that more apparent. I also think the DNA-150 is happier with a 1900hz crossover when driven to levels that the woofer is capable of. And last but not least I liked how it sounded.

    By all means tinker away.
  13. Re: DW-774S/DNA150 + Celestion TF0818 design/build

    Sounds like a good choice of tradeoffs ;) I thought some of it might have to do with pattern control but wasn't sure. That is one of the reasons I chose this design. I was curious about waveguides. The other reason was that my bookshelves can't keep up with my sub (epic 12). I have no doubt that these can ;D
  14. I played around with this crossover some after I learned a few tricks working with the DNA-150, Here is a new crossover using only 6 parts that measures better and is linear phase/time aligned.


    Frequency response, this is with an 8 ohm resistor in parallel with the tweeter, I changed it to 7 ohm for the final design but did not save the graph. the 7 ohm lowers the tweeter response, roughly >2200 Hz about a dB.

  15. Will this kit be offered again in the near future? ::)

    It has been out of stock since November last year... :-\


  16. That's up to Erich, I really like this design especially with the new crossover. The design using the EOS-8 waveguide fits in the same enclosure as the Fusion-8 and Alpha-8 so that made more sense from a logistical standpoint having to stock only one flat-pack for all three models.
  17. I have been listening to these again since picking up a DTA-100 from the PE tent sale but realized I had made one more adjustment since posting the last schematic. Here is the current crossover just in case someone wanted to build them:


    I know they are no longer available as kits but the woofer and waveguide have very thin flanges so surface mounting would not be a problem. Exceptional value and in my opinion sound much better then the Fusion-6/Volt's. I hope these will be offered as kits again at some point, hint hint Erich ;)
  18. buon giorno, sono Marco dall'Italia volevo realizzare il progetto qui spiegato ma non riesco a trovare le misure delle aperture di reflex potreste gentilmente darmi dei dati .....grazie
    Good day, I'm Marco from Italy wanted to carry out the project explained here but I can not find the measurements of the openings reflex could kindly give me some information ..... thanks

    Attached Files:

  19. Hi Marco, the ports are 1.5" high, 3.75" wide and 7.5" deep, converted to metric they roughly 38mm high x 95mm wide x 190mm deep.

  20. grazie mille :) ;)
  21. I've built a couple of speakers before but never did the satellite (These would be considered satellites, right?) and subwoofer thing before.

    What freq would you cross these over to a subwoofer and what would be the maximum power you would put in them?

    Would they require a high pass filter?

    If using a sub, could you get away with a sealed enclosure? The bass would drop off at a higher frequency I realize but this could perhaps negate the need for a high pass filter?
  22. Yeah these could be considered satellites in a system like that, usually I think of satellites as the little speakers included in HTiB systems.

    Ideally you would use them ported and crossed to a subwoofer at 80 Hz. You can use them sealed but they will roll off up around 150 Hz which I feel is too high to crossover and the subwoofer may become more localizable. You should use a high pass crossover with them if running with subwoofers however they don't require it even when ported and are safe without a high pass as long as they are powered with less then 100w.

    If using a high pass at 80hz or higher you can safely use an amplifier rated up to 400w. The continuous power rating for the woofer is 100w but it will handle 400w short term without any problems and that 6dB of amplifier headroom can make a difference on very dynamic material.
  23. Thanks for the detailed answer.

    However, running with no filter ported at 100 watts I see excursion of 10 mm at 30 hz and then another around 4.5 mm at 70 hz. If I run a 80hz 2nd order high pass filter I limit the xmax to 3.5 mm at 100 hz. Am I missing something or should I run a filter?
  24. It is highly unlikely the levels at 30Hz in almost any genre of music will be as high as those in the midrange so you will clip the amp before you reach that kind of excursion. That said the woofer is suspension limited and that will cause the cone to stall out or soft bottom well before it get to 10mm. I have used mine without a high pass with more then 100w with no excursion trouble. You won't hurt the speaker using without a high pass so you can try it out and decide for yourself which what you want to do
  25. Thanks! I appreciate your words of practicality in the real world.

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