+ Reply to Thread
Page 1 of 22 12311 ... LastLast
Results 1 to 15 of 326

Thread: Altec 9844-8B

  1. #1
    Senior Member Skywave-Rider's Avatar
    Join Date
    Nov 2007
    Location
    New York, NY
    Posts
    313

    Altec 9844-8B

    Hi,
    I just got a pair of Altec 9844-8Bs. They use two 414 16E woofers and a 902 HF driver
    with 811B horn.

    I'd like to refresh the crossover and add a tweeter, of course that would require a custom network.

    Well, I have a pair of K-77s I took out of my Klipsch Heresies which were replaced by
    the Bob Crites tweeter. I could use those. I might, at some point in the future upgrade
    to a better tweeter (Beyma/Crites/?), so hopefully it would be compatible.

    Since I have no design skills, but can solder like a champ,
    I wonder if anyone can point me in the right direction for a crossover design that would work well.

    Thanks!

  2. #2
    Senior Member CONVERGENCE's Avatar
    Join Date
    Dec 2004
    Location
    CANADA
    Posts
    295
    Yes you can build a 3 way second order reverse polarity crossover.

    Parts List

    Capacitors
    C1 = 1.54 uF
    C2 = 16.83 uF
    C3 = 1.37 uF
    C4 = 12.31 uF
    Inductors
    L1 = 0.4 mH
    L2 = 3.3 mH
    L3 = 0.32 mH
    L4 = 3.22 mH

    2nd Order Reverse Polarity

    6400 Hertz / 800 Hertz

    8 Ohm Tweeter / 8 Ohm Mid / 8 Ohm Woofer
    2.45 db Bandpass Gain, Spread = 8 : 3 octaves
    Attached Images Attached Images  

  3. #3
    Senior Member Skywave-Rider's Avatar
    Join Date
    Nov 2007
    Location
    New York, NY
    Posts
    313
    Thanks Convergence!
    I am currently specing out the components at Parts Express.
    I am in your debt.
    Best wishes!

  4. #4
    Senior Member
    Join Date
    Apr 2003
    Location
    Toronto
    Posts
    3,722
    Quote Originally Posted by Skywave-Rider
    Thanks Convergence!
    I am currently specing out the components at Parts Express.,,, snip ,,,,,,
    - FWIW, you should add to your order a qty of ;
    - ( 4 ) 50 watt , 8 ohm variable Lpads .
    - You'll need 2 per crossover .
    - Ask Convergence where to locate them in the circuit & how to wire them in .


  5. #5
    Senior Member Skywave-Rider's Avatar
    Join Date
    Nov 2007
    Location
    New York, NY
    Posts
    313
    Thanks, I was just about to press "submit order." Convergence, what do you think? Do those L-Pads go in the tweeter and squawker circuits? Or function as his/los? Can I do without them? I like the idea of going without them, but that might be unrealistic?
    Thanks in advance.
    Last edited by Skywave-Rider; 11-11-2007 at 12:30 PM. Reason: misread

  6. #6
    Senior Member CONVERGENCE's Avatar
    Join Date
    Dec 2004
    Location
    CANADA
    Posts
    295
    LPad (Driver Attenuation Circuit)

    Z = 8 Ohms

    A = 2 db

    Parts List

    Resistors
    R1 = 1.65 Ohms
    R2 = 30.9 Ohms

    AFTER L3 AND C3 FOR HORN AFTER C1 L1 FOR TWEETER
    Attached Images Attached Images   

  7. #7
    Senior Member Skywave-Rider's Avatar
    Join Date
    Nov 2007
    Location
    New York, NY
    Posts
    313
    Thank you Convergence and Earl. I will add the L-pads. Did a little reading about them last night, so I think I understand how they work. You know what they say, a little knowledge....

    I understand the K-77 (EV T 35) may not be the best tweeter, but I have a pair on hand, and I'd consider changing to a better tweeter if I think the 3 way setup has potential for me.

    There's always a chance I'll go back to the original 2 way network setup with new caps. But I've got to try this and I'll post when I get it done.

    Greatly appreciated, great board.


  8. #8
    Senior Member Skywave-Rider's Avatar
    Join Date
    Nov 2007
    Location
    New York, NY
    Posts
    313

    Crossovers Completed

    OK, the crossovers are done. I'm going external because I want little as possible to change on the 9844-8Bs. I also made a rig to mount the tweeters which go on top of the cabinet. When I test them I'll report back and post pics of the entire rig. If these work out, I will want to test one speaker with a 2 way crossover for comparison. If anyone has suggestions on how to do this without making up an entirely new crossover, that would be great. I am assuming the original crossovers are no good. Wish me luck.
    Attached Images Attached Images  

  9. #9
    Senior Member Skywave-Rider's Avatar
    Join Date
    Nov 2007
    Location
    New York, NY
    Posts
    313

    They work

    Yes they work. I have not tested the speakers in a room, so I'll try to do that next week and get pics. My initial impression is that the K77 tweeter is not blending well. It seems to muck up the imaging, which is what I remember from my Heresies; I changed the Klipsch out to a Crites tweeter and that was solidifying. I have the K-77s (EVT35) mounted on the Altecs in their proper vertical orientation. I hear phase problems; but I will have to listen closely next week.

    I have a feeling after I put them in a listening room I'll either want better tweeters (APT-200?) or will revert back to 2 way. If I revert, does anyone have an opinion as to whether or not I should copy the original network, modify my 3 way, or do something completely different?

    Thanks!
    Last edited by Skywave-Rider; 11-28-2007 at 08:44 PM. Reason: Poor verbiage.

  10. #10
    Junior Member djgaloot's Avatar
    Join Date
    Sep 2007
    Location
    Portland
    Posts
    19
    Skywave,
    Nice looking crossovers. Though I do not have any input, I am watching with great interest as I have similar speakers (Malibus) and also plan on making a 9844 clone. Some have suggested active crossovers as an alternative. I was thinking of a ribbon tweeter for the HF. Right now mine are all stock with the old stock 800hz crossovers.

  11. #11
    Senior Member hmolwitz's Avatar
    Join Date
    Sep 2005
    Location
    Darien CT
    Posts
    325

    Quote from a fellow member

    http://www.audioheritage.org/vbullet...ad.php?t=10252

    "The T35 is not a very good tweeter. Most start taking a dive at about 10K Klipsch would select those that would make it to 15K and send the rest back. I have a pair tested in a anechoic chamber just makes it to 10k I replaced the diaphrams & now get 14k. Diaphrams are inconsistent due to phenolic weight and thickness. The newer T35/ k77 today will get 15k to 17k. This tweeter should have been retired along time ago."
    __________________
    Maron Horonzak


    The specs on that would not be as good as the 902, you would be better off leaving it alone.
    The 902 should be fairly linear out to beyond 15K, but this thread:
    http://www.audioheritage.org/vbullet...ad.php?t=14690

    Will give you the full powers of Mr Zilch brought to focus on the lacking of the Altec HF horns, along with the assorted wisdom of many other members.
    Part of the beauty of that speaker is the simplicity of a 2 way.

    Many find the 902 a wonderfully acceptable driver, it is probably marginally better than the earlier versions.

    Enjoy the road, it is not the destination that matters.
    Nice job on those crossovers
    Harry

  12. #12
    Member Art J.'s Avatar
    Join Date
    Jul 2004
    Location
    Connecticut
    Posts
    57
    Quote Originally Posted by Skywave-Rider View Post
    Yes they work. I have not tested the speakers in a room, so I'll try to do that next week and get pics. My initial impression is that the K77 tweeter is not blending well. It seems to muck up the imaging, which is what I remember from my Heresies; I changed the Klipsch out to a Crites tweeter and that was solidifying. I have the K-77s (EVT35) mounted on the Altecs in their proper vertical orientation. I hear phase problems; but I will have to listen closely next week.

    I have a feeling after I put them in a listening room I'll either want better tweeters (APT-200?) or will revert back to 2 way. If I revert, does anyone have an opinion as to whether or not I should copy the original network, modify my 3 way, or do something completely different?

    Thanks!

    Hello gang, that is a great looking crossover for sure.
    It seems that phasing problems bother you as much as
    they bother me.
    Adding a tweeter causes chronic phasing problems anyway
    but you could help the situation by getting the electrical phasing
    in line by using the "cascade method" on that crossover. The
    modified diagram shown should be self explanatory when thinking
    in terms of phase shift.
    In your case, the no cost experiment means moving the C1 input side
    to the C2 output side keeping the shown polarity.
    That will help for the most part but to fine tune it,
    you will need an oscilloscope and audio oscillator.
    It may improve overall balance too.
    Have fun. Great soldering.......
    Attached Images Attached Images  

  13. #13
    Senior Member Skywave-Rider's Avatar
    Join Date
    Nov 2007
    Location
    New York, NY
    Posts
    313
    Quote Originally Posted by Art J. View Post
    Hello gang, that is a great looking crossover for sure.
    It seems that phasing problems bother you as much as
    they bother me.
    Adding a tweeter causes chronic phasing problems anyway
    but you could help the situation by getting the electrical phasing
    in line by using the "cascade method" on that crossover. The
    modified diagram shown should be self explanatory when thinking
    in terms of phase shift.
    In your case, the no cost experiment means moving the C1 input side
    to the C2 output side keeping the shown polarity.
    That will help for the most part but to fine tune it,
    you will need an oscilloscope and audio oscillator.
    It may improve overall balance too.
    Have fun. Great soldering.......
    Thanks Art, and to all.
    I intend to do the cascade mod next week. I understand how feeding the input of C1 from the output of C2 adds delay, but I'm not clear on why that is required -- I think it's because C2's value is much higher though the electrical delay must also be frequency dependent. I don't know how that can be adjusted other than changing the capacitance value if the crossover points remain constant. Clearly I need to read a little about this which I will try doing.

    At this point it's a learning experience, and since I can go back to 2 way, I feel pretty good about the mods because I'm not molesting the speakers.

    One reason I can't do changes too rapidly is because the Altecs are currently not in my home; they're at my office. I live in a tiny studio apt..
    Tiny studio apts are not Altec friendly.

    Thanks again!
    ._._.

  14. #14
    Senior Member CONVERGENCE's Avatar
    Join Date
    Dec 2004
    Location
    CANADA
    Posts
    295
    Nice job on those crossovers. Now before doing any other changes try them with your system first. The 3 way Altec monitors is not a new invention. I can think of The Mastering Lab with their 411, 511E and EV tweeter. And a similar model designed in the 70's.Rod Stewart had a pair.
    Attached Images Attached Images  

  15. #15
    Member Art J.'s Avatar
    Join Date
    Jul 2004
    Location
    Connecticut
    Posts
    57
    > I intend to do the cascade mod next week. I understand how feeding the input of C1 from the output of C2 adds delay, but I'm not clear on why that is required -- I think it's because C2's value is much higher though the electrical delay must also be frequency dependent. I don't know how that can be adjusted other than changing the capacitance value if the crossover points remain constant. Clearly I need to read a little about this which I will try doing.

    Well, I'm not a good explainer but the idea is to treat the mid and tweeter as a separate
    second order reverse polarity circuit. This gives hope for phase alignment at the highest
    x-over frequency where phasing effects would be most noticeable. C1 L1, C3 L3.
    Then working from the top down, the woofer circuit is added where phasing differences
    will not be as noticeable. Their will always be a phase conflict with passives, so put it where
    it will do the least damage.
    With the strait 3 way band pass arrangement, I see no hope for
    getting any form of alignment.. It seems to be a non-issue with most. Don't know why.

    > At this point it's a learning experience, and since I can go back to 2 way, I feel pretty good about the mods because I'm not molesting the speakers.

    You did such a great job building the x-over, I'm hoping you can make the best
    of what you got.
    I tried finding a link on cascade filters without much luck. I picked up on these before the
    internet and built with good results. All I found was this link that may be helpful and
    confusing at the same time. The more you study it, the worse it gets.

    http://www.trueaudio.com/st_xov_1.htm





+ Reply to Thread

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Altec vs. JBL vs. TAD
    By RacerXtreme in forum Lansing Product DIY Forum
    Replies: 21
    Last Post: 10-11-2007, 02:52 PM
  2. Plantronics to Acquire Altec Lansing
    By watchman in forum Lansing Product General Information
    Replies: 10
    Last Post: 08-31-2006, 09:04 AM

Posting Permissions

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