Tuning Qes Qts Bl Mms
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 Multi-Way Conventional loudspeakers with crossovers

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 4th May 2004, 08:34 PM #1 P Zolt   diyAudio Member   Join Date: Mar 2004 Location: Ontario Tuning Qes Qts Bl Mms Qes=1/(ws*Cms*Res) and Cms=Vas/(rho0*c^2 *Sd^2) and Res=(Bl)^2 / Re Bl=sqrt((rho0*c^2*Sd^2*Re)/(ws*Vas*Qes)) Qes=w0*Mms/((BL)^2/Re)=w0*Mms * Re/(BL)^2 Qts value is determined by Qes=ws*Mms/Res, where Res=(Bl)^2/Re BL = f(Fs, Vas, Qes, Qms, Re, Sd) Formula from the board. I have no idea how to use. Using Unibox Software +Qes = +Qts = -BL +Re = -Spl Can I assume +Mms = +Qes =+Qts =-Bl A change in the voice coil Re does not effect Qts yet really drops Spl = not good. If I raise Qes (driver Re at Fs) the Qts goes up to a very nice .38 = great and SPL drops by 1 db, mostly in the midrange leaving the bass intact. Slight drop in BL. A higher Qts of .38 is an ideal situation for this Pro driver. Can I do this ?? Power Applied 50W Fs 38.2 Re 5.0 Ohm Qms 7.73 Qes 0.32 Sd 858.0 Vas299.0L Xmax 5.5mm SPL at 1 W 1 m 99.1 db SPL at 2.83 Vrms 1m 101.1 db Qts 0.307 Effective Qts 0.307 Mms 60.03g Cms 0.289mm/N Rms 1.864 Kg/s Bl 15.00Tm Ref efficiency, n 5.007% Applied voltage 15.81 Vrms ======================== Now with a change to Qes of .40 SPL at 1 W 1 m 98.1 db SPL at 2.83 Vrms 1m 100.2 db Qts 0.38 Effective Qts 0.38 Mms 60.03g Cms 0.289mm/N Rms 1.864 Kg/s Bl 13.42Tm Ref efficiency, n 4.006% Applied voltage 15.81 Vrms I will be adding Dammer Varnish to the cone area to change the sound and add mass. Is this the trick for a higher Qts higher Qes lower Bl yet leaving the Voice coil Re as is ?? How many grams need to be added for a Qts of 38. I can post a jpg of Parameters or SPL plot, just ask TIA
 4th May 2004, 08:42 PM #2 markp   diyAudio Member   Join Date: Oct 2003 Location: L.A., CA You will not be changing Re by coating the cone. You will be changing Mms, which will affect Qms and Qts. __________________ If it sounds good... it is good!
RobM
diyAudio Member

Join Date: May 2003
Location: West Orange, NJ, USA
Quote:
 Originally posted by markp You will not be changing Re by coating the cone. You will be changing Mms, which will affect Qms and Qts.
Fs and Qes, too. Fs will go down, Qms, Qes, and Qts will go up.

markp
diyAudio Member

Join Date: Oct 2003
Location: L.A., CA
Quote:
 Originally posted by RobM Fs and Qes, too. Fs will go down, Qms, Qes, and Qts will go up.
Yep....
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 20th April 2005, 03:10 PM #5 MethMan diyAudio Member   Join Date: Jun 2004 Location: Praha what's happens with Cms and Bl? Stays the same? I Try to calculate added mass for spkr. I have no suitable software for it. Now: Qms=1,85 Qes= 0,44 Qts=0,36 Mms=65g Cms=330e-6 Fs=35 Bl=13,3 Re=5,6 My resuts for added 45g: Qms=2,61 Qes=0,58 Qts=0,47 Mms=110g Fs=26,4 I assumed the Bl and Cms stays same. Is it true? OTOH I can see small (3%) difference in parametres (could be affected with changing Cms) in table in Dickanson's LDCookbook. Misfortunately the mentioned part is very brief. There is a reference to Tom Nouissiane (probably distorted name- sorry) article in Speaker Builder from 80's which isn't procurable for me.
 20th April 2005, 03:17 PM #6 Ron E   diyAudio Member     Join Date: Jun 2002 Location: USA, MN CMS and BL are constants. (Fs/F1)^2=(Mmt+Mass added)/Mmt Qe1 = Qes*(Mmt+Mass added)/Mmt Qm1= Qms *(Mmt+Mass added)/Mmt Vas is constant __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. —Aldous Huxley
 21st April 2005, 03:21 AM #7 Ron E   diyAudio Member     Join Date: Jun 2002 Location: USA, MN Sorry, brain slip. CMS and BL are constants. (Fs1/Fs2)^2=(Mmt+Mass added)/Mmt Recalculate Qes and Qms with new Mmt and Fs2. Vas is constant __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. —Aldous Huxley
 21st April 2005, 08:02 AM #8 MethMan diyAudio Member   Join Date: Jun 2004 Location: Praha Clear. Thanks.
planet10
frugal-phile(tm)
diyAudio Moderator

Join Date: Oct 2001
Location: Victoria, BC, NA, Sol III
Quote:
 Originally posted by RobM Fs will go down/ Qts will go up.
a graphic example

dave
Attached Images
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 21st April 2005, 12:56 PM #10 MethMan diyAudio Member   Join Date: Jun 2004 Location: Praha Btw. I've got advice that paint, with exception of say resin-based thin impegnacy of the cone just for light stiffening, is not so good solution of adding mass because of higher loading or even possible overloading loudspaker's joints. Right solution is to fasten interrupted-ring shaped ballast made of non-magnetic metal directly into the former.

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