Page 1 of 2 12 LastLast
Results 1 to 15 of 19

Thread: Two way LCR for home theater

  1. #1
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10

    Two way LCR for home theater

    Hi there, I've been lurking on these boards for quite some time.

    Were in the process of building a new house and with that a dedicated HT room. (see attachment)
    The room is L 6.4 x W 5.0 x H 2.8 Meters

    At this time I have Klipsch RF-83 and RC-64 as LCR and will use those when the HT is completed, but for a future upgrade I've been looking for DiY plans for home theater LCR's.

    I'd like to build an active two way system (or three ? ). Zilch's Mega system caught my attention.
    http://www.audioheritage.org/vbullet...&postcount=419

    I'm thinking of using the
    JBL 2352 horn
    http://www.usspeaker.com/jbl%202352-1.htm
    2435HPL Compression driver.

    From sub x-over (50-80hz) to horn x-over (800-1200) I was considering two Usher 15HM. Two of these placed horizontally below the horn. Seperate enclosures.
    http://www.partsexpress.com/pe/showd...number=296-630

    In the front of the room I will be building a false wall which can house the horn and seperate box(es) for the LF drivers. The LF boxes and the horn can be positioned by making a holdingshelf between the studs of the false wall, so the LCR's will be flush mounted in the false wall so to speak. The three front speakers will be positioned in ear level height with the perforated screen covering at least the center monitor. The front of the wall will be covered by acoustic panels and the unused cavity can be filled with fiberglass for bass trapping.



    So is this viable, the 2352 horn + compression driver, Usher LF driver, behringer electronic crossover and one amp for each lf and hf for each of the three monitors?
    Attached Images Attached Images  

  2. #2
    Senior Member 4343's Avatar
    Join Date
    Jan 2006
    Location
    SJ, CA
    Posts
    517

    Only Center behind Screen?

    It might be difficult to match the center to the LR pair if it's the only one experiencing the HF rolloff of the screen. Maybe not, but if it was me, I'd put all the fronts behind the screen just to be consistent. Sounds like the horns should have plenty of output, and losing some through the screen would be no big deal...
    Mike Scott in SJ, CA
    Drive 'em to the Xmax!

  3. #3
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10
    Quote Originally Posted by 4343 View Post
    It might be difficult to match the center to the LR pair if it's the only one experiencing the HF rolloff of the screen. Maybe not, but if it was me, I'd put all the fronts behind the screen just to be consistent. Sounds like the horns should have plenty of output, and losing some through the screen would be no big deal...
    I'll be using a SMX curved perforated screen, supposedly the loss is minimal. I guess I can experiment and take measurements when the time comes.

    So, guys, has anything like this been done before? Perhaps there is another DIY HT LCR project you could point me to for ideas and inspiration?

    The reason I chose the 2352 horn is because size is no issue and and the spread fits nicely for an LCR since they are supposed to be point sources and there will be less room interaction.
    I'm unsure about compression driver though.
    I chose the Usher LF driver because it's been getting alot of positive feedback from other projects. The response seems to fit well for an 800-1000hz x-over. With the behringer digital xover I'll probably use 24 or 48 db db/octave rolloff. Perhaps there is a JBL model which would be better suited to handle 80-1000hz?

  4. #4
    Senior Member pos's Avatar
    Join Date
    May 2007
    Location
    France
    Posts
    2,628
    Just for inspiration, here is Greg Timbers' take on a DIY HT system:
    http://www.audioheritage.org/vbullet...ead.php?t=9951

    Perhaps there is a JBL model which would be better suited to handle 80-1000hz?
    1200FE?

  5. #5
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10
    Quote Originally Posted by pos View Post
    Just for inspiration, here is Greg Timbers' take on a DIY HT system:
    http://www.audioheritage.org/vbullet...ead.php?t=9951

    1200FE?
    Breathtaking!

  6. #6
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10
    http://www.partsexpress.com/pe/showd...number=296-630

    Are there any drawbacks for using an 15"'s up to 800-1000hz? cone breakup etc? Should I perhaps opt for a three way with the 15"'s working up to 200-300 range and have multiple 6.5" or 8" work up to 800-1000hz?

  7. #7
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10
    Ok, let's see if I get more feedback if I take a different angle here.

    I've heard the Klipsch Thx ultra II monitor and this is more natural sounding than my RF-83 but lacks dynamics and attack. I'd like something that does both, natural sound with no harshness and dynamics that'll knock your breath out.

    I would like to diy, three monitors for LCR use. Is it possible to build something which would demolish the KL-650 thx ultra II LCR and the Klipsch RF-83 / RC-64 combo, possibly rival the Juibilee?

  8. #8
    JBL 4645
    Guest
    NoMjolnir


    Watch some of these rare interviews with Mr. Tomlinson Holman AKA (THX) because what the rest of the guys said about placement behind the screen is the best place, but there’s (more to that).

    Here’s the link to the page watch THX baffle wall and mathematics? Or you can watch the whole lot.

    http://www.audioheritage.org/vbulletin/showthread.php?t=12476

  9. #9
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10
    Quote Originally Posted by JBL 4645 View Post
    NoMjolnir


    Watch some of these rare interviews with Mr. Tomlinson Holman AKA (THX) because what the rest of the guys said about placement behind the screen is the best place, but there’s (more to that).

    Here’s the link to the page watch THX baffle wall and mathematics? Or you can watch the whole lot.

    http://www.audioheritage.org/vbulletin/showthread.php?t=12476
    Amazing videos, Mr Holman was really interesting to listen to. I believe when he was about explain the .2 in 10.2 he he trailed off and talked about how satellites could be smaller because of the 80hz crossover so he never explained why .2. I wonder if the reason is that you can feel where sub 80hz is coming from even though you can't necessarily localize it by hearing.

    I'm considering building a front baffle wall, with flush mounted lcr and and an LLT subwoofer solution.

  10. #10
    Senior Member pos's Avatar
    Join Date
    May 2007
    Location
    France
    Posts
    2,628
    Maybe you should contact your JBL dealer and see if you can get some 1200FE.
    If Greg Timbers chose these for its 80-800hz needs then I would say this is the best you can choose too.

  11. #11
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10
    I've modelled a thx baffle wall in my HT. I've angled the wall on the left and rigth so that the right and left channel will be 30 degrees on the sweetspot when flushmounted.

    The cavity behind can be used for an LLT subwoofer, that way I dont have to build boxes.
    Attached Images Attached Images  

  12. #12
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,720
    Quote Originally Posted by NoMjolnir View Post
    Is it possible to build something which would demolish the KL-650 thx ultra II LCR and the Klipsch RF-83 / RC-64 combo, possibly rival the Juibilee?
    Sure.

    Hell, demolishing the Jubilee isn't all that difficult either. What's your budget?


    Widget

  13. #13
    JBL 4645
    Guest
    NoMjolnir

    I like the approach that you’ve taken at the last minute.


    What is the size of the loudspeakers, in relation to the depth behind the baffle wall area? Some (lean way) well be needed to get easy access to remove them if a fault was to occur, say a blown driver?

    The professional THX baffle walls have access from behind the wall where you’d climb up a ladder and therefore be able to maintain and damage.


    Pinewood Studios England

    This is what a typical THX screen looks like at the Empire Leicester square London.
    It’s more of an art with interior architectural design as well.


    Empire Leicester Square London

    The Empire Leicester Square London a JBL installation!
    http://www.audioheritage.org/vbulletin/showthread.php?t=13057

    THX screens usual use plasterboard but that can be a messy affair. There are other types of (affordable materials) to use for a (baffle wall) that don’t cost.

    Don’t forget the absorbent material to cover over the (barrier wall surface), because that part where Tom Holman, mentioned the (reflectivity bouncing around behind the screen) was fascinating

    Here is a basic how it works sort of thing at the THX website.

    Behind-the-screen baffle wall
    http://www.thx.com/cinema/builtTHX/baffle.html

    16 feet in width

    18 feet in length

    The length of the HF horn is what I looked at because of the shrinkage of the rooms depth will decrease once you place this and the (compression driver on the back) I think another 3” of room depth space will be lost, 13” for the HF and compression driver?

    Overall Length 10" / 254mm


    So plain out the mounting depth around the centre part of the baffle a few times over. I know it sucks when the room shrinks down.


    Or you can use a flat area surface that will more in you’re favour as it will be far easier.

  14. #14
    Junior Member
    Join Date
    Dec 2007
    Location
    Norway
    Posts
    10
    Quote Originally Posted by Mr. Widget View Post
    Sure.

    Hell, demolishing the Jubilee isn't all that difficult either. What's your budget?


    Widget
    For the front LCR the budget is around 2000-3000$ each.

    If I use electronic crossover that is not included in the budget, neither is amps.

    For the surround and surround back channels I want to take my time and experiment with direct radiators and sound sprayers. So for now I focus on the LCR.

  15. #15
    JBL 4645
    Guest
    NoMjolnir

    Evening

    I’ve just been looking around Google image and stumbled on a different loudspeaker management crossover system. Myself for example, I’m using a Behringer DCX2496 a few others here also use them in the home. But a found a different one and I just need a few extras minutes to research it and look for the best low prices.

    Edit

    Omni drive compact plus loudspeaker management crossover system.

    Whoa BUGGER ME! £2,419.99! That is a bit over the top!
    http://www.ultimate-av.co.uk/acatalog/signal_signal_bss.html



    I’d stick with the Behringer DCX2496 as the above will cost an arm and leg! It’s a good looking one I must say I do like the appearance of it.

    But just in case you win the national lottery here’s a user manual to skip though. It’s not the only loudspeaker management crossover as there are a few more like the (dbx4800) that are THX approved and used in only one cinema the Empire Leicester square. And that has four inputs with eight outputs configurations, but still its around the £2K price tag range.

    Omni drive compact plus loudspeaker management crossover system user manual pdf file
    http://www.usc.edu/student-affairs/gzcoffee/printable/Technical-Audio-Omnidrive.pdf

    dbx 4800
    http://www.dbxpro.com/4800/4800.htm

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Interesting "White Van" article
    By SEAWOLF97 in forum Miscellaneous Gear
    Replies: 35
    Last Post: 01-03-2010, 04:04 PM
  2. C40's in a Theater Room - OK?
    By arwun in forum Miscellaneous Gear
    Replies: 6
    Last Post: 11-10-2007, 02:57 PM
  3. Paragon & C35's in a Theater Room?
    By arwun in forum Lansing Product General Information
    Replies: 36
    Last Post: 11-06-2007, 12:34 PM
  4. Surround 8340a or 8330a for Home Theater?
    By Minatogawaman in forum Lansing Product General Information
    Replies: 3
    Last Post: 12-19-2006, 04:28 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •