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Longshot: Anyone done T/S measurements on vintage Zenith 10" woofers??

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  • kevintomb
    replied
    Chris Roemer


    Ran the T/S parameters, but not sure I am getting accurate results.

    I used 38 Grams for my added mass, but got Vas 100 liters and Qts of .56

    The T/S I got from online several posts up is quite different. But also feel it may be a bit too low Vas wise.

    Leave a comment:


  • kevintomb
    replied
    Originally posted by Chris Roemer View Post
    Qts?
    Should be running the full T/S today with added mass.

    Ran out of time as comp is set up on dining room table and dinner took precedence.

    Leave a comment:


  • Chris Roemer
    replied
    Qts?

    Leave a comment:


  • kevintomb
    replied
    Success!

    Finally got my other comp running, did a basic impedance sweep

    Woofer was Fs 41.5 Hz with LIMP

    My box was tuned to 46 Hz, did a new port measured it to be 39.5 Hz (LIMP also) and it made an improvement for sure.

    Hard to believe 6.5 Hertz would matter a lot, but it added just the right amount of deeper bass "weight" and removed some of the mid bass boominess.,

    These old zenith woofers (if found cheap) are still quite usable, and decent even today!

    Leave a comment:


  • kevintomb
    replied
    Originally posted by AEIOU View Post

    Why is the tweeter so offset? Looks like you went a bit too far.
    This was just some box designed to try them out, not a box to be finished.

    Leave a comment:


  • AEIOU
    replied
    Originally posted by kevintomb View Post
    Click image for larger version Name:	IMG_1005.JPG Views:	0 Size:	361.8 KB ID:	1446350 These are the ones I found online of the same exact model, in my quickly made ugly MDF box....

    Rola/Zenith 49-1270, average for two

    Vas - 48 liters
    Fs - 38 hz
    Qms - 10
    Qes - .50
    Qts - .47
    Re - 7.4 ohms
    Le - 1.97 mH
    SPL - 91 dB



    I am not certain if the Vas is accurate. I did a quick MDF box of 1.875 cuft (( 53 liters)) tuned to 40 Hz and not sure I am getting the best low end possible is all
    Why is the tweeter so offset? Looks like you went a bit too far.

    Leave a comment:


  • kevintomb
    replied
    Originally posted by Chris Roemer View Post
    (if those parms are correct) Your box should NOT be bad (upper 30s).
    Box could be bigger. I get low 30s in 2.5cf, tuned to mid 30s.
    What is odd, that is the exact box size they came in originally 1.875 Cu ft. but came to that number NOT trying to match the original but just using Box Port Design II

    They have decent bass, but just feel the lower end is a bit lacking. Bought them just for Nostalgia, had some decades ago.
    I modeled upper 30s also, but not sure it is getting THAT low. It does have powerful decent bass, but for the size I think lacking a "Bit" deep bass wise.

    Will experiment a bit with stuffing and port tuning.

    As soon as house stuff is done will do an impedance sweep and see if tuning is on etc.

    Leave a comment:


  • Chris Roemer
    replied
    (if those parms are correct) Your box should NOT be bad (upper 30s).
    Box could be bigger. I get low 30s in 2.5cf, tuned to mid 30s.

    Leave a comment:


  • kevintomb
    replied
    Click image for larger version  Name:	IMG_1005.JPG Views:	0 Size:	361.8 KB ID:	1446350 These are the ones I found online of the same exact model, in my quickly made ugly MDF box....

    Rola/Zenith 49-1270, average for two

    Vas - 48 liters
    Fs - 38 hz
    Qms - 10
    Qes - .50
    Qts - .47
    Re - 7.4 ohms
    Le - 1.97 mH
    SPL - 91 dB



    I am not certain if the Vas is accurate. I did a quick MDF box of 1.875 cuft (( 53 liters)) tuned to 40 Hz and not sure I am getting the best low end possible is all
    Last edited by kevintomb; 07-17-2020, 08:57 PM.

    Leave a comment:


  • Longshot: Anyone done T/S measurements on vintage Zenith 10" woofers??

    As it says. I bought some,(very cheap price) do not have my audio testing rig hooked up, but found some T/S parameters on another site, but feel they may not be accurate for sure.

    These were used in the Zenith MC3000 model from around 1980 about and also in the Zenith Allegro 3000 model from the 70s

    Yes I Know how to test them, but house painting and stuff is cramping my measuring and set up corner of the living room!
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