sundownz Posted June 3, 2011 Report Share Posted June 3, 2011 People ask me this alot... the short answer is that they make the speaker better. The long answer can be shown on some graphs. This graph shows inductance over excursion for a basic motor design. The center is at rest, left is rear stroke, and right is forward stroke. Why is the graph shaped this way ? Have you ever looked at inductors for a crossover ? You can get a high value in a small package with an iron core. So... what is a speaker motor ? A partially iron core inductor! As the coil moves back it gets more iron in the core! So the inductance rises. As it moves forward it gets more air in the core so it drops. Pretty cool, huh ? Now... the field can be absorbed by a conductive material in or around the coil -- so shorting rings come into play. One approach, which we use on the SA series and NS v.2 series, is a pole cap shorting ring -- note how it reduces forward inductance and at rest inductance. But not much in the way of rearward... Well the NS v.2 and Z v.2 both have a large magnet ID ring -- notice the huge effect on rearward inductance and at-rest inductance ? As a note... the SA will also have this ring shortly too. Now... having BOTH rings like the NS v.2 has now and the SA will have soon... huge effect across the board! Not only is the inductance more linear but it is much much lower. Why is this good ? 1) More power delivery to the coil as inductance causes "rise" 2) Less distortion -- inductive distortion is odd order and unpleasant; although a fairly small part of total distortion. 3) More high-end extension as inductance is a 6dB per octave low-pass crossover. 4) These rings also act as heat-sinks; although this effect is not a large reason to use them in and of itself. Can a speaker sound good without them ? Sure! Many great sounding speakers don't use them and they are pretty expensive too so don't always represent a good price to performance ratio. I do not plan to use magnet ID rings on lines less expensive than the SA series, for example, as the ring represents such a high % of the total cost of the speaker at that point (large chunk of aluminum, copper, or brass). But they do have benefits and I figured some of you might like to know what those are. Quote - Jacob Fuller - Owner, Sundown Audio - Sundown Audio on FACEBOOK - Please DO NOT PM ME -- use my email address -- [email protected] Link to comment Share on other sites More sharing options...
VOPA Posted June 3, 2011 Report Share Posted June 3, 2011 The new Z.v3 will have both of the shorting rings as well, correct? Quote 04 Monochrome LT Chevy Tahoe -A few wires, half a speaker, some watts -All Black 6's -Paint to Match, SS Bumper, Black grills. -HID'ed and LED'ed -A few performance enhancers I have two nice subs for sale, but I am not allowed to help my fellow forum members by offering it to them for a nice price via my signature, sorry Link to comment Share on other sites More sharing options...
dwright27 Posted June 3, 2011 Report Share Posted June 3, 2011 Good read. Quote 2006 F-150 4 DC XL M2 18's Walled Daily Driver XS Power 4 DC 3.5kw Team DC Team S.P.L. Lot of Audio Technix and 1/0 DC Audio Dealer American Bass Dealer XS Power Dealer Audio Technix Dealer Link to comment Share on other sites More sharing options...
sundownz Posted June 3, 2011 Author Report Share Posted June 3, 2011 The new Z.v3 will have both of the shorting rings as well, correct? Yes. Quote - Jacob Fuller - Owner, Sundown Audio - Sundown Audio on FACEBOOK - Please DO NOT PM ME -- use my email address -- [email protected] Link to comment Share on other sites More sharing options...
MaliBOOM Posted June 3, 2011 Report Share Posted June 3, 2011 thanks for the info Jacob Quote www.TheAutoSkin.com MaliBOOM v2"2010 Bagged Malibu on 20s"<< click here<<< Excursion on 42s Build log<<Click here<<< Instagram-@theAutoSkinRyan @TheAutoSkin Owner of The Auto Skin Link to comment Share on other sites More sharing options...
sundownz Posted June 6, 2011 Author Report Share Posted June 6, 2011 This thin sleeve has a nice effect at rest and on rear-ward -- seems to lose effect combined with the magnet ID ring, though, as that is equal to the magnet ID ring only. ----- So now lets do a thick sleeve : Full 1.0mm thick -- and the effect is MUCH better and also alleviates the issue of being cancelled out by the magnet ID ring. The only problem is you need to add more motor to compensate for this type of sleeve as it widens the gap a good bit -- for this example the pole had to go down from 35.7mm OD to 33.7mm OD to fit this sleeve. If the design budget allows for this then no problem -- the issue you end up with is spending more money on the motor by adding magnet to it. The benefit is that the sleeve is the most linear method simulated -- the Le curve is completely flat in this case. In most cases price to performance the magnet ID ring would be a better selection unless you are going for ultimate reference level. Quote - Jacob Fuller - Owner, Sundown Audio - Sundown Audio on FACEBOOK - Please DO NOT PM ME -- use my email address -- [email protected] Link to comment Share on other sites More sharing options...
sundownz Posted June 6, 2011 Author Report Share Posted June 6, 2011 * SA motor -- the top aluminum piece acts as a pole cap ring. * The brass piece is a magnet ID ring from a Z v.2 motor. This goes around the inside of the magnets below the top plate / above the back plate. It is sitting on the SA motor simply for reference purposes. * Acoustic Elegance drivers with pole sleeve shorting rings Quote - Jacob Fuller - Owner, Sundown Audio - Sundown Audio on FACEBOOK - Please DO NOT PM ME -- use my email address -- [email protected] Link to comment Share on other sites More sharing options...
Autruche Posted June 6, 2011 Report Share Posted June 6, 2011 Interesting stuff. Always the simple things that solve the most complex problems. Quote Need Test Tones/Sine Waves? Click Here!My Saab 9000 build1993 Saab 9000 Aero 5spdPioneer - Zapco - Hifonics - Sundown Audio - O2 Audio - RE AudioJust Say No To Rear SpeakersJust Say No To CCA WireReal Men Drive StickHit me up on Facebook, if you want Link to comment Share on other sites More sharing options...
sundownz Posted June 6, 2011 Author Report Share Posted June 6, 2011 We used a pretty small motor for this discussion... 120mm OD magnet utilized. When I made enough room for the sleeve we dropped off 34% of the motor force factor (BL^2/RE) -- in order to get this back the magnet had to go all the way up to 150mm OD and in turn the back and top plate OD both had to expand as well. So much more steel and much more magnet. 634g magnet to a 1109g magnet -- we had to gain 75% magnet mass. Total motor went from 1890g to 3112g -- so a 65% gain overall in mass not counting mass added by the sleeve. So it is fairly significant in terms of cost to get a highly functional sleeve and to "gain back" the desired motor force lost by making room for it. And again, if this pans out for the target cost of the driver these thick sleeves do work great. Quote - Jacob Fuller - Owner, Sundown Audio - Sundown Audio on FACEBOOK - Please DO NOT PM ME -- use my email address -- [email protected] Link to comment Share on other sites More sharing options...
Autruche Posted June 6, 2011 Report Share Posted June 6, 2011 Alright, not as simple as I originally thought. Quote Need Test Tones/Sine Waves? Click Here!My Saab 9000 build1993 Saab 9000 Aero 5spdPioneer - Zapco - Hifonics - Sundown Audio - O2 Audio - RE AudioJust Say No To Rear SpeakersJust Say No To CCA WireReal Men Drive StickHit me up on Facebook, if you want Link to comment Share on other sites More sharing options...
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