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Thread: More home theatre questions.

  1. #1
    Senior Member Doc Mark's Avatar
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    More home theatre questions.

    Greetings, Friends,

    RDG's neat result in making a nice dual woofer center channel has got me thinking....

    When undertaking such things, isn't it best to stick with similar driver types, IE: cones with cones, and horns with horns, etc.? I have been thinking about cobbling together a center speaker for our L300's, and after seeing RDG's great results, remembered that I have a pair of 116H-3's, in new condition, plus a single 052Ti, also in new condition, which could be used in such a project. Add to that a single, good condition 5" 104H-3, and hey, this might just work! I even have a single 4312A enclosure that might work for making something similar to what RDG did. BUT....

    I am skeptical whether such a center speaker would do any good, at all, when combined with our L300's. I could use our 4411's for rear speakers, or the 4333's, when they are finished. But, I thinking that the combo of horn systems, with the cone system of such a center speaker, would not work well together. Am I right? I'm thinking that, if nothing else, the difference in efficiencies would make the center unable to keep up with the other goodies. BUT...

    If I used that dual-8" 3-way center speaker, with the 4411's, I think it might work better. But....

    I don't want to use the 4411's instead of the L300's.

    So, what are your thoughts on all this stuff, Friends? Thanks, and God Bless!

    Every Good Wish,
    Doc

    P.S. A tip O' the old hat to RDG for his good idea, and for his neat execution of same!
    The only thing that can never be taken away from you, is your honor. Cherish it, in yourself, and in others.

  2. #2
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    Thnk accurate voice reproduction!

    I have recently experimented with several center channel configurations for my primary HT.

    My main speakers in this system are 3-ways consisting of JBL components including a 15" 2226, a 2426 compression driver and horn and a 2505 slot tweeter. These are driven with a 802d Crown XLS - 500WPC. In many ways, you might consider that these "centers" are a modern update to the venerable old L300.

    Since music reproduction is not a primary consideration in HT, the two main channel speakers are NOT as important as most folks would tend to think. This, IMO, is the result of the typical way mixing for HT material is done in the studio.

    By far, the most important channel in a HT is the center and, in the typical HT mix, it provides a high percentage of the total sound in these multi-track recordings. When planning for this component, consideration should be given to the accurate reproduction of VOICE material.

    When I changed my center recently, it was a total transformation of the system.

    For my center, I took an old L100 cab and installed a 12 inch 2206 and 2425 compression driver with a small aftermarket horn crossed at 1200 and I built a new grill which was necessary as a result of the new driver configuration and baffle modifications.

    Anyway, if your L300s will remain as the centers in this system, I beleive a JBL 12" 3-way with a similar sensitivity rating would be one excellent choice. Obviously, there are many other suitable choices that would also fit this bill.

  3. #3
    Senior Member rdgrimes's Avatar
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    Quote Originally Posted by Doc Mark View Post
    When undertaking such things, isn't it best to stick with similar driver types, IE: cones with cones, and horns with horns, etc.? I have been thinking about cobbling together a center speaker for our L300's,
    It all depends on how precise you need the results to be. "Voice matching" is the name of the game. L-C-R speakers need to have the same voice or the effect is not the same. (same holds true for surrounds) To some extent a good AVR with PEQ setup routines can match dissimilar speakers, but it can't change the basic sound of a speaker. So if you're the picky type, you need the same drivers and preferably the same cabs all around. If you're not so picky, maybe not. The one caveat with centers is that they need very little LF response, so most dedicated centers use the same MF and HF drivers, with different LF. This gives you voice matching in the vocal ranges, where it's needed.

  4. #4
    Senior Member Doc Mark's Avatar
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    Morning, Guys,

    Thanks, very much! That's pretty much what I thought would be the case. So, if I choose to mess with all this, which I may or may not decide to do, then I will need the 4333's in the rear, and another speaker for the center channel. I have only a few other JBL MF and HF components, which are the 2445J's, and 2380A horns, or the 2445J's and the 2311 horns, which might be too much for a center speaker. But I also have some Altec stuff. Maybe I'll mess with a 10" or 12" + Altec 902-16B driver. For horns that would work with that driver, I have a pair of Community 60° x 40° fibreglass horns, and also a small pair of Emilar horns, which I seem to remember as 90° x 40°. I'll have to dig them up, to be sure. And, I have one pair, each, of Altec's 811B's, and 511B's. So, maybe some of this stuff might work out. I'd probably lean towards the Altec 902-16B driver, as I always liked the natural reproduction I got from that CD. Interesting stuff, to be sure. Thanks, again, Guys! Take care, and God Bless!

    Every Good Wish,
    Doc
    The only thing that can never be taken away from you, is your honor. Cherish it, in yourself, and in others.

  5. #5
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    Quote Originally Posted by rdgrimes View Post
    The one caveat with centers is that they need very little LF response, so most dedicated centers use the same MF and HF drivers, with different LF. This gives you voice matching in the vocal ranges, where it's needed.

    I would differ on this. I think that to really match, the LCR should all be set to the same size (small or large, but in this case large) and use similar drivers. There is more to it than just the vocal range, especially when you start in on DVD-A and SACD formats.

    Also recognize that in Dolby decoding, mono goes to the center channel, and most bass seems to be mixed mono.

  6. #6
    Senior Member rdgrimes's Avatar
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    Quote Originally Posted by toddalin View Post
    I would differ on this. I think that to really match, the LCR should all be set to the same size (small or large, but in this case large) and use similar drivers. There is more to it than just the vocal range, especially when you start in on DVD-A and SACD formats.

    Also recognize that in Dolby decoding, mono goes to the center channel, and most bass seems to be mixed mono.
    All true, as far as it goes. A competent surround AVR with good bass management and multi-channel EQ is required.

  7. #7
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    Matching equals less hassle of EQ’ing. With mismatching forget about the idea okay.

    Place the LCR side-by-side and the differences will be within a few db of each other in tone noticeable with the highs because there in different space in-relation to each other therefore requires EQ.

    Spacing of the speakers’ out along the front of the room’ increases the issue and EQ is paramount, to deal with the tiny little things, to get it all looking smart on the RTA and with smoothing panning sounds.

    Try this experiment

    Patch the LCRS into an audio mixer line inputs 1, 2,3, 4 and 5 use single output to play over single loudspeaker and play the automatic pink noise on the AVR and let it cycle around while setting each channel with equal level with an SPL db metre placed in front of you.

    Once you’ve got the levels all matched the tone should sound like a continuousness pink noise sound rather than something that has gabs in the sound.

    Change anything like frequency on one of the channels and by the time it reaches that channel it would stick out like sore thumb, some goes with level.

    Changing the phase won’t show any audio or visible sign unless its an all-channel pink noise signal of all-six. Change the frequency level or phase and that channel will curse minor disturbance in the signal.

    It’s all good stuff.

    If you rub your thumb over your fingers and move it from side to side while placed in front of you the rustling sounds almost equal depending on where you move. In straight line from left to right while it moves into the centre and by the time it gets near to the other side of your hearing it might change shape.

    Pitch might rise up or you might be drifting your arm inwards slightly therefore the tone goes up in frequency and db.

    Just don’t let your friends see you doing this otherwise they’ll, think you’ve snapped your wig.

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