Menu
Forum
What's new
New posts
Live Activity
Search forums
Members
Registered members
Classifieds Member Feedback
Car Audio Discussion
General Car Audio
Car Audio Build Logs
Car Audio Equipment
Subwoofers
Speakers
Amplifiers
Head Units
Car Audio Help
Wiring, Electrical and Installation
Enclosure Design & Construction
Car Audio Classifieds
Car Audio Classifieds
Car Audio Wanted
Classifieds Member Feedback
Gallery
New media
New comments
Search media
SHOP
Shop Head Units
Shop Amplifiers
Shop Speakers
Shop Subwoofers
Shop eBay Car Audio
Log in / Join
Test
Forum
Search
Search titles only
Search titles only
Log in / Join
Search
Search titles only
Search titles only
What's new
New posts
Live Activity
Search forums
Members
Registered members
Classifieds Member Feedback
Menu
Reply to thread
Forum
Car Audio Equipment
Subwoofers
Anyone Have Experience With These:
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Message
<blockquote data-quote="Kyle_Keating" data-source="post: 7133674" data-attributes="member: 582385"><p>I choose not to optimize any magnet shapes because I wanted to eliminate differences in material cost and B. The XBL^2 motor does not need a deep magnet stack like overhung, but using the exact same magnets we weed out that difference. Sure, in real life, we could choose the same magnet volume and use a much wider but shorter magnet and it would be stronger. But the same could be done for overhung with a deep t-yoke (think of Fi's examples) so I did'nt feel it was necessary to go down that path.</p><p></p><p>I don't quit buy that XBLL can simply be shorter. I have played this motor depth game many times and at the end of the day, an underhung motor can't be less deep than an overhung motor etc etc. If you want something to move a lot, you have to have clearance for the cone, spiders and then the end of the voice coil. Pick any point on the voice coil, then pick xmax. That point move move xmax both directions no matter what kind of speaker you have. In the case of underhung and XBLL, the magnet might be less deep, but the gapplate makes up for that difference. You can tuck an underhung or XBLL gap into a frame, but then that frame has to be made that much taller in comparison so the spiders don't hit the gap. Its always the same problem.</p><p></p><p>With the rebate in the gap, i see that as very similar to an undercut t-yoke which can be implemented on an overhung coil and yield great low inductance benefits such as the AE AV12 and AV15 speakers. I agree, since the design is innate to XBLL motors, its a rather serendipitous advantage to the motor without any additional alterations to the return path.</p><p></p><p>The tighter gap thing is very troublesome and probably has more to do with suspension differences, but I can also say this, if we double up the layers and use a vc that is twice as short, we need a wider gap obviously, but you also claim you can tighten up the slop in the gap. The problem i see is slop should not only account for rocking problems and tolerances that the suspension and assembly can't account for, but also thermal expansion. When you make the coil thicker oyu need more room for that on top everything else. I'm not saying this is bad or good, it's just the same problems with all coils.</p><p></p><p>In regard to inductance, in my opinion, by the time you double the turns on the XBLL coil, I don't see the advantage in inductance or flux modulation. I have measured some XBLL subwoofer examples that really have about the same inductance as comparable other types. Just take this example.</p><p></p><p><a href="http://www.diycable.com/main/product_info.php?cPath=24&amp;products_id=681" target="_blank">DIYCable.com : Intro » Home » Exodus Subwoofers »</a></p><p></p><p>Great product and this is not a knock in any way. But its inductance is exactly the same as the TC LMS-R which also does not use a shorting ring over the poll. Both have beefy coils and the normalized BL is within 5% of each other. Without getting in the klippel FEA or integrity of the designs, from a glace, the Max-X has higher xmax and more BL, but not by much but its a larger motor too. I don't like to use real world examples because between those drivers, there are too many other differences to really draw accurate conclusions which is way I FEA'ed examples above with controlled variables.</p><p></p><p>I have little doubt there are great examples of XBLL drivers out there, as there are great examples of underhung, overhung and LMS drivers. There are a lot more variables that go into making a good driver. The point of my analysis was not to show one design was better than the next, but to show that holding some fundamental constrains, we can't really get anything for free. Now lets get back to work, we're wasting valuable time chatting on a forum!</p></blockquote><p></p>
[QUOTE="Kyle_Keating, post: 7133674, member: 582385"] I choose not to optimize any magnet shapes because I wanted to eliminate differences in material cost and B. The XBL^2 motor does not need a deep magnet stack like overhung, but using the exact same magnets we weed out that difference. Sure, in real life, we could choose the same magnet volume and use a much wider but shorter magnet and it would be stronger. But the same could be done for overhung with a deep t-yoke (think of Fi's examples) so I did'nt feel it was necessary to go down that path. I don't quit buy that XBLL can simply be shorter. I have played this motor depth game many times and at the end of the day, an underhung motor can't be less deep than an overhung motor etc etc. If you want something to move a lot, you have to have clearance for the cone, spiders and then the end of the voice coil. Pick any point on the voice coil, then pick xmax. That point move move xmax both directions no matter what kind of speaker you have. In the case of underhung and XBLL, the magnet might be less deep, but the gapplate makes up for that difference. You can tuck an underhung or XBLL gap into a frame, but then that frame has to be made that much taller in comparison so the spiders don't hit the gap. Its always the same problem. With the rebate in the gap, i see that as very similar to an undercut t-yoke which can be implemented on an overhung coil and yield great low inductance benefits such as the AE AV12 and AV15 speakers. I agree, since the design is innate to XBLL motors, its a rather serendipitous advantage to the motor without any additional alterations to the return path. The tighter gap thing is very troublesome and probably has more to do with suspension differences, but I can also say this, if we double up the layers and use a vc that is twice as short, we need a wider gap obviously, but you also claim you can tighten up the slop in the gap. The problem i see is slop should not only account for rocking problems and tolerances that the suspension and assembly can't account for, but also thermal expansion. When you make the coil thicker oyu need more room for that on top everything else. I'm not saying this is bad or good, it's just the same problems with all coils. In regard to inductance, in my opinion, by the time you double the turns on the XBLL coil, I don't see the advantage in inductance or flux modulation. I have measured some XBLL subwoofer examples that really have about the same inductance as comparable other types. Just take this example. [URL="http://www.diycable.com/main/product_info.php?cPath=24&products_id=681"]DIYCable.com : Intro » Home » Exodus Subwoofers »[/URL] Great product and this is not a knock in any way. But its inductance is exactly the same as the TC LMS-R which also does not use a shorting ring over the poll. Both have beefy coils and the normalized BL is within 5% of each other. Without getting in the klippel FEA or integrity of the designs, from a glace, the Max-X has higher xmax and more BL, but not by much but its a larger motor too. I don't like to use real world examples because between those drivers, there are too many other differences to really draw accurate conclusions which is way I FEA'ed examples above with controlled variables. I have little doubt there are great examples of XBLL drivers out there, as there are great examples of underhung, overhung and LMS drivers. There are a lot more variables that go into making a good driver. The point of my analysis was not to show one design was better than the next, but to show that holding some fundamental constrains, we can't really get anything for free. Now lets get back to work, we're wasting valuable time chatting on a forum! [/QUOTE]
Insert quotes…
Verification
Post reply
Forum
Car Audio Equipment
Subwoofers
Anyone Have Experience With These:
Top
Menu
Home
Refresh