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Thread: Potential Model 19 Upgrades

  1. #1
    Webmaster Don McRitchie's Avatar
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    Potential Model 19 Upgrades

    Rather than hijacking the S7 vs Model 19 thread where this was originally posted, I thought that I would start a new thread in response to garyl posting following:

    I have NEVER, not even once, heard anyone say they needed to do any sort of upgrading to make them sound better.
    As a current Model 19 owner I think I am in a position to offer an opinion on this. Like any speaker, the Model 19 is not without its faults and there has actually been a fair bit of discussion on this board and on Todd White's Altec board on useful upgrades.

    The most common complaint regards the resonant 811B horn and its effects on coloring the midrange response. There are many reported solutions that all have their adherents. The first line of attack is usually attempting to damp the horn. I've heard of techniques from applying putty to the outer bell, coating the horn with the same goop used in auto rustproofing to a mix of paint and sand. Another line of attack has been to cut the three webs at the mouth of the horn along the weld line. Supposedly Altec did this themselves in the last production runs of the similar 511 horn and used a rubber fitting to connect the top and bottom halves of the webs.

    The second issue regards the network. While it was innovative in its use of EQ, it is still somewhat primitive compared to what can be accomplished today. Iconic Manufacturing recognizes this limitation and has announced that they will be developing a "Model 19 Super Crossover" that more comprehensively tunes the response.

    Personally, I have not been keen to make any physical modifications so that I have turned to outboard EQ to address these issues and a third one - restricted LF response. While deeper than the preceding Valencia, the Model 19 still has a noticeable bass roll-off starting at around 50hz. I use a parametric equalizer to bump up the response around 3db at 40 hz over a narrow one octave band and this seems to be effective at gaining extension. I have the upper midrange cut back around -4db centered at 3khz with a 2.5 octave band to address the resonance and network limitations. I also have the UHF boosted at around 12kz to address a lack of UHF response in my room.
    Regards

    Don McRitchie

  2. #2
    Senior Member edgewound's Avatar
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    One of the simplest and easy fixes for the approx 1000hz ringing in the horn, is to apply adhesive-backed Dynamat or a similar product to the inside top and bottom of the horn bell. This makes the ringing stop and really brings things into focus. It's a non-invasive and reversable fix.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  3. #3
    Senior Member Baron030's Avatar
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    In Vance Dickason's "Loudspeaker Design Cookbook", he makes a reference to the use of vibration absorbing materials. One of which is manufactured by "E-A-R Specialty Composites". On their web site I found some interesting Technical White Papers.

    Products like Dynamat Xtreme are examples of "Constrained-layer damping (CLD) systems". So, if you want to find out the how they work, then go to the following web site, its interesting reading.

    http://www.earsc.com/HOME/engineering/TechnicalWhitePapers/Contrain/index.asp?SID=60

    Also, checkout some of the other articles listed on their index page: http://www.earsc.com/HOME/engineerin...dex.asp?SID=11

    Baron030

  4. #4
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    I have to admit my hearing is not what it used to be. My first set of 19s bought new had a foam insert around the exterior of the horn. After many years it turned to mush and was removed. I never heard the need to replace it but I am sure others might.
    The Super XOs sound like something that could be interesting but at what price? Would it be possible to upgrade the existing ones for a little better sound with new caps of higher quality?
    I do have a set of the new Altec N 1500-8A XOs in my clones and I actually think it is an improvment over the standard 1200Hz XO.

    Keep in mind I am not a good source for auditioning these subtle changes and I can be very dangerous with a soldering iron and a DMM. Probably why I stick with playing with my wood .

    The big questions I have here is if one really can't hear a ring in the horns, is it worth the trouble to fix it?
    Bass roll-off is another story and I think in my room which is overly reflective and not as warm as I would like, I am not able to detect exactly what this is. I have cement floors, block walls covered by older paneling with a large fieldstone fire place and just a pool table and small bar. Have to keep a dehumidifier going constant so I can't really carpet the floor.
    Does it make any sense to do upgrades on the speakers if your room is not ideal and can't be?
    Speaker placement is another issue and I am sure it could be much better but I am stuck with what I have as I am sure many of us are.

    Is it safe to say, In a perfect world/room, perfect speakers will make a big difference but what I have is liveable now?

    Gary

  5. #5
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    Getting the ring out of the horn is very much worth the time spent. Take your choice; mix and match.... all help.

    Cut the webs, fill with RTV of your color choice
    Damp the outer with Dynamat, Q-Pad, sand and latex or EAR
    Bolt them down securely with the rear supported and the flange bedded down to a gasket.

    Cyclotronguy

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