5 channel DYI?

Discussion in 'Home Theater Projects' started by Christpher_S, Jul 12, 2004.

  1. Christpher_S

    Christpher_S Stunt Coordinator

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    I think I would like to build the speakers for the little media room I'm setting up. I have the woodworking skills and equipment so that's not an issue. If you guys were working with a budget of $1000.00 or so for the drivers and crossovers to build a 5 channel system, what would you go for?

    The Kit 281's look good to me but I think I read that their center channel isn't timber matched to the towers. Do I have that right? I'm pretty particular about timber matching all the speakers in a surround system. I thought about using another Kit281 as the center but I don't have anywhere to put it. I'm not overly concerned about size and SAF isn't that big an issue either. The only real constraint on size is being able to mount the rear channels high up on the wall without them looking stupid or banging heads.

    I already have a Shiva and 250W PE plate amp that I need to build a box for so that is covered. I might do a second one at some point though.

    Thanks in advance for any help!

    -Chris
     
  2. Joey Skinner

    Joey Skinner Second Unit

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    Check out GR Reseach. You could get the AV3 towers for mains and the AV3S for a center and AV1 for rear surrounds with Sonicaps for about $1000. Read their reviews, great speakers for the money.
     
  3. ThomasW

    ThomasW Cinematographer

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    Chris,

    The Kit281 are quite good speakers. And unlike kits using little midwoofers, the 281's have solid bottom end performance, so a second sub shouldn't be needed.

    Of course the Adire center is timber matched to the other Adire kits, since they use the same drivers.

    The Kit81's make nice surrounds, and yes it's timber matched to the other speakers as well.
     
  4. Scott Simonian

    Scott Simonian Screenwriter

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    I have a pair of 281s in front along with a LCC from Adire. They are matched quite well I'd say. Not to forget that the center packs a wallop itself. Great for movies. (Duh, center channel)

    If you can afford it, I would recommend getting two pairs of 281s and a LCC. That would sound great! I still need another pair or two for my surrounds and rear centers.

    [​IMG] [​IMG]


    BTW-Christpher, have you decided on an alignment for your Shiva? I would recommend an EBS alignment. That should rock the place with authority on movies.
     
  5. Darren_T

    Darren_T Second Unit

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    I'd go with GR-Research AV1's or AV2's. I have 5 AV2's... can't get more timbre matched than 5 of the exact same speaker.

    Danny supplies high quality components such as foil inductors and has the option for a sonicap upgrade which I took advantage of. Wonderful speakers, I can't say enough about them. I've had mine for quite a while now and have built many others.

    I've had a home theater setup with a center, mains and smaller rears etc... It sounded nice but there is nothing like having 5 of the exact same speaker. With the AV2's you can turn your center on it's side or stand it up as it is about the same size as most other center speakers. It sounds great either way.

    No, I'm not affiliated either [​IMG] Just a happy customer.

    Here is one of my AV2's
    [​IMG]
    [​IMG]

    Here is a pair of AV1's I built
    [​IMG]

    Check Danny's kits out at:
    www.gr-research.com

    Best bang for the buck in my book.
     
  6. DanWiggins

    DanWiggins Second Unit

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    The LCC is timbre matched to all our HT speakers (281s, 81s, and 51s). They'll blend fine. It's also designed for wide horizontal dispersion, unlike the "MTM on its side" approach.

    Additionally, approximately 50-60% of the total energy of the front speakers (L/C/R) comes from the center. It's carrying the majority of the load. It should be at least as big and capable as the L/R speakers, if not moreso. Our solution was a full 3 way in a higher tuned box to keep the output levels up without compressing/distorting.

    Dan Wiggins
    Adire Audio
     
  7. ThomasW

    ThomasW Cinematographer

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    I've been building speakers for more than 40yrs. And throughout that time one axiom has remained true.

    "There's no replacement for displacement"

    So something to consider when looking at loudspeakers is how much air is displaced. The greater the displacement the higher the potential output. Also speakers that have higher displacement don't need to work as hard for a target output level, therefore the distortion levels are lower.

    For example

    The Adire 8" woofers have an Sd of 231cm^2 vs the GR-Research M-130 Sd is 95.05 cm^2.
    A MTM design using the Adire 8" driver therefore has 462 cm^2 of cone area as opposed to the M-130's 190.1 cm^2.

    Also little midwoofers are somewhat hamstrung when it comes to reproducing lower frequencies at any significant output level. For obvious reasons reproducing LFE at reasonable SPL's requires what? Displacement.

    Personally I want a main speaker that has solid outout one full octave below the crossover point. If we use a standard THX 80Hz XO point, I want my speakers to have solid output to 40Hz or lower. (note I'm not talking about a -3dB 40Hz down point). Having solid output to 40Hz guarantees there won't be a hole in the response between the mains and the sub.

    Dan W is certainly correct about a horizontal MTM being a poor choice for center channel speakers. For too many years I had a matching horizontal MTM as my center. When I replaced it with a TM with flanking woofers (a driver layout like the large Adire center), there was a significant improvement.

    BTW, there are some really nice pitures of assembled Adire kits on their gallery page
     
  8. Darren_T

    Darren_T Second Unit

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    I disagree on one point. Using a GR MTM horizontally has little of the problems of a typical MTM laid horizontally. Danny has performed tests and there is little difference with his AV2 in a horizontal position as compared to vertical. He of course could explain it much better than I can. He has the numbers and I won't attempt to go much further than I have here.

    I agree that the Kit281's crank. I've built a pair of the floor standers. Their characteristics just didn't appeal to me personally. Awesome output though.
     
  9. ThomasW

    ThomasW Cinematographer

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    There are laws of physics involved here too. And no one I know has yet to defeat those laws for the lobing/comb filtering effects of a horizontal MTM.

    Yes one can 'improve' the dispersion by off-setting the tweeter. And yes one can 'improve' the performance by tweaking the crossover. (a task further complicated when one is using 1st order, or series XO's). But in a head to head comparison, to a center made using a TM with flanking woofers, a 'tweaked' horizontal MTM simply isn't as good.
     
  10. Darren_T

    Darren_T Second Unit

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    I agree with you ThomasW, I know there are the laws of physics... just stating that the AV2's horizontal dispertion is rather good on it's side as well as vertical.
     
  11. Bryan.T

    Bryan.T Agent

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    I might be wrong here, but I thought the problem with MTM centers is when you get so far off center. Therefor, if all your seating is with in that range then you would not see any problems with the MTM center. Feel free to correct me if I am wrong. Since I will be looking to build a simular set up in the near future.

    Thanks,
    Bryan
     
  12. Darren_T

    Darren_T Second Unit

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    Bryan,

    Yes, you are correct. It is my opinion that if your seating is all fairly close to center the problems of an MTM on it's side will not be as apparent. I've had my AV2 MTM center for quite a while now with several setups and even fairly far off axis this center works quite well. I can sit all the way to one side of the room and the dialog is still quite acceptable if not superb. Wow, I don't get to use the word superb all that often. Sweet. [​IMG]
     
  13. ThomasW

    ThomasW Cinematographer

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    Darren,

    We've gone from 'rather good', to 'quite acceptable' to 'superb' in 3 posts. Not bad ...... :wink:

    Bryan,

    The some of the issues associated with a horizontal MTM are mitigated by having the viewers sit 'on-axis' with the 'H-MTM' tweeter. But even then the characteristics of a 'H-MTM' are less desirable than those of a TM with flanking woofers. And actually if one has the space, a vertical MTM with flanking woofers makes an even better center, IMO.

    Using very high-end drivers (Scan-Speak, Eton, Focal, etc,), I've built and lived with both 'H-MTM' and TM flanking woofer designs. This isn't idle speculation on my part.

    So if one has the 'option', I strongly suggest a TM with flanking woofers. If that's not an option, then obviously a 'H-MTM' is significantly better than no center.
     
  14. Darren_T

    Darren_T Second Unit

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    Well,

    In my book Rather Good, and Quite Acceptable are the same thing... Superb on the other hand is quite a step up. I did qualify that with "if not" which errs on the side of caution but I'll stick with Superb [​IMG]
     
  15. Christpher_S

    Christpher_S Stunt Coordinator

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    Thanks to everyone for the replies. I see some real passion here for Adire and GR. I think I'm probably going to do the Adire setup because of the larger drivers. I also don't hear high frequencies real well due to ear abuse years ago so a little brightness usually sounds good to me. As recommended above, I'm looking at one LCC, 2 Kit281's and 2 Kit81's.

    It will probably be a month or so before I can afford to get them and I need to finish a woodworking project for my wife first anyway. She made it pretty clear that she won't be happy if I build speakers before finishing her project. Oh well, I'll just use my B&W 303's and center for a little while. At least my front soundstage will match. The only thing I have for surrounds is an old pair of Bose that have been in the closet for a few years. Bleck.

    I have two more Adire questions though.

    Will it be difficult to match the front levels to the rear being that front will be 4 Ohm and rear will be 8 Ohm?

    What is the recommended amp wattage to drive the Adire speakers to reference levels? I like to have a good bit more power on tap than required for the actual peaks I'm hitting. Would 150WPC from a quality amp give me all the volume I need with power to spare? I'll be in a 13' X 17' room for now, so I don't imagine it will be real hard to fill with sound. I want enough amp that I won't need to upgrade if I get a new house in a few years and build a real theater room though.

    Thanks again for the help and for any additional advice.

    -Chris
     
  16. Christpher_S

    Christpher_S Stunt Coordinator

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    Darren,

    Nice looking speakers. Are the ones on the bottom Walnut?

    -Chris
     
  17. ThomasW

    ThomasW Cinematographer

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    Chris

    Power ratings for the Adire kits are posted on their website.

    Yes 150 watts/speaker will be more than adequate. With 8-8" midwoofers and a sub, no you won't have any problems filling the room with sound

    Matching the output levels between the 8 and 4 ohm speakers shouldn't be a big issue with the controls on most receivers and or pre/pros.
     
  18. James W. Johnson

    James W. Johnson Screenwriter

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    Will it be difficult to match the front levels to the rear being that front will be 4 Ohm and rear will be 8 Ohm?
    >>>>>>>>>>
    Most likely it wont be an issue unless your rears are like 86dBs and take 50 watts or something like that.

    What is the recommended amp wattage to drive the Adire speakers to reference levels?
    >>>>>>>>>>>

    The Kit 281s will take all you can throw at them, I'd recommend an honest 100 wpc amp or better.
     
  19. Darren_T

    Darren_T Second Unit

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    Thanks, yes the speakers on the bottom are curly walnut. The baffles are solid wood laminated to MDF. Most woodworking professionals would consider that a no-no but with the limited width it is quite stable.
     
  20. James W. Johnson

    James W. Johnson Screenwriter

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    IMO little midwoofers have trouble with midrange as well.

    I started out with 6.5" MTMs and felt they did a good job with everything to some degree but as time goes on they are satisfying me less and less. 5 1/4" drivers are out of the question completely in my book and 6.5" drivers just barely cut it.
    I think I'll stick with 7" on up from now on.

    I'm going with 15" mids this time with an SD of 4 8" drivers. [​IMG]

    This might be a far fetched theory but I was thinking about this post and the kit 281s last night and how several people have complained that the midrange lacked...IMO the Kit 281s have no trouble at all with midbass. Maybe the problem is that seemingly 99% of home audio speakers use 6.5" and smaller midwoofers and people just dont know how mids should sound.

    6.5" drivers would make some finee headphones though. [​IMG]
     

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