Anyone Have Experience With These:

[whitedragon551 5,000+ posts]

CSS (Creative Sound Solutions):

http://meniscusaudio.com/css-sdx10-p-773.html

http://meniscusaudio.com/css-sd12-p-569.html

http://meniscusaudio.com/css-trio8-p-946.html

They are all XBL^2 motors which is quite appealing since Im building for SQ.

Click to read more...

 

[dkdub 10+ year member]

those 8's look great... haven't had any experience myself with those but I do love me some xbl motors.

 

[whitedragon551 5,000+ posts]

those 8's look great... haven't had any experience myself with those but I do love me some xbl motors.

Im not familiar with XBL^2 other than they are supposed to be very minimal distortion SQ woofers. Any incite?

 

[dkdub 10+ year member]

Basically that's it. My old brahma 10 is probably my favorite sub of all time. It's almost odd to hear loud sub bass with low distortion, most people who heard mine when I was running it told me it sounded "different". But they were mostly bassheads and used to just plain "loudness"

 

[Wingman0121 10+ year member]

Basically that's it. My old brahma 10 is probably my favorite sub of all time. It's almost odd to hear loud sub bass with low distortion, most people who heard mine when I was running it told me it sounded "different". But they were mostly bassheads and used to just plain "loudness"

Ahhh Brahma... do enlighten more about the motor and how it sounds different.

 

[ciaonzo 5,000+ posts]

Basically that's it. My old brahma 10 is probably my favorite sub of all time. It's almost odd to hear loud sub bass with low distortion, most people who heard mine when I was running it told me it sounded "different". But they were mostly bassheads and used to just plain "loudness"

I'll second that with regards to my LMS drivers.

 

[whitedragon551 5,000+ posts]

Here is some info I found:

As far as the technical aspect, it breaks the magnetic gap into more than one region, meaning instead of a typical motor that has a single high flux gap in the center, there are two or more gaps in the motor that have narrower high flux regions. Then, the coil is sized to optimize BL over the curve, mainly so that the coil will extend from the center of the top gap to the center of the bottom gap, that way when it leaves one high flux region, it enters the other. Most subwoofers use the voice coil to achieve a higher excursion, the downside of that is that the higher the excursion, the less coil is in the gap, so you lose motor strength and control, so distortion is increased and overall BL is decreased. Adire's method uses the gap more effectively and distributes it over a shorter coil, while decreasing required top plate length, thus the production cost. Coil length is decreased compared to designs like overhung and evenhung, so inductance is less and transient performance and efficiency is better. It's one of the best, if not the best motor design out there.
BTW, the main benefit of this topology isn't fully realized with subwoofers. This actually sees more benefit with midbasses, midranges, tweeters, and full range drivers. Typically, and XBL^2 driver will still only have 30% of the distortion other designs have at 70% of maximum linear excursion (x-max). In many cases, this translates to around a 1% distortion rating at 70% excursion, while others are between 3 and 5%. This allows a design that yields very clean sound at higher volumes and can fully realize the potential of enclosures such as sealed and infinite baffle, where excursion is naturally higher and SQ tends to suffer at high volumes due to that.

The biggest benefit of XBL^2 is that it allows a smaller driver to have higher output levels and a wider bandwidth, meaning a 6" midbass driver could potentially have the depth of a typical 8" driver and rival some 10" drivers for depth, and be very linear and accurate doing it. Their Extremis midbass driver is a good example of this, it is a 6.8" driver having a 13mm one way X-max, only a .13mH inductance, and is ideal for ported boxes tuned in the 30s, offering in-room extension down to the 20s. Inductive rolloff occurs around 8khz and there are no nasty breakup modes from the cone, crossover will typically be 2-3khz. To give you an idea, the Scan-Speak Revelator and SEAS Excel drivers, which are renowned high end home audio drivers, have a good bit more inductance, right at half or less than half the excursion level, less motor strength, and less bandwidth. As their designs progress even further, Adire is going to be a very difficult manufacturer to beat, or even level with for that matter.

Apocalypse, think about a magnet reacting to another magnet. The most strength will naturally occur when the magnets are closest together, and become weaker as they move further away. Similarly, in the case of a speaker, you have a fixed magnet and the voice coil, in which the coil is an electromagnet. They will either repel or attract each other with current applied. With a typical speaker, the center point of the motor (permanent magnet) is where the strength is focused, and at rest, the voice coil is centered in that. As current is applied, forces either repel or attract this, moving the coil up or down. As you can imagine, as it moves, less and less of the voice coil is retained within the gap, so magnetic control over the entire voice coil is reduced. The idea with these motor designs is that the longer the coil, the more there is to apply strength to, so you'll get more excursion with a longer coil. XBL^2, from a functional standpoint, has two or more points that focus strength over a narrower gap, just think of it as two magnets, and as the coil leaves one gap, it will enter another, which allows a higher level of control and motor strength than if it were one. As the coil moves further from one gap, it moves closer to the other, so you will have more control over the coil since you are always within a strong point of flux, and you will get more motor strength over the excursion limitations.

About efficiency, XBL^2 is actually more efficient than most motor designs out there overall, it is the soft parts that tend to bring down the efficiency of the subs they are used in. Adire uses epoxy treated paper cones in their subs, which are heavier than many other materials, but chosen for their damping ability, they also use a wider profile surround as opposed to a taller one, which controls the subwoofer very well, but cuts down surface area, and tighter suspension designs than many. XBL^2 isn't really the reason a Brahma isn't as efficient than other subs, but rather the reason it isn't less efficient than it already is. Adire is also more true with their sensitivity specs than many other manufacturers. Remember as well, that sensitivity specs are very misleading and give no clue to how loud a subwoofer will be at higher volumes. Excursion is low at 1 watt , a subwoofer with a parabolic BL curve will do well at 1 watt, but lose motor strength (thus efficiency) at higher volumes. XBL^2, on the other hand, offers flat BL and will give more BL at higher volumes than many other motor designs, making it more efficient with the power.

I'm guessing you're talking about LMT (Linear Motor Technology)
LMT basically it makes the coil fatter at the top and bottom of the voice coil so that you get more motor strength as more coil leaves the magnetic gap. It is basically a 2nd layer of coil at the top and bottom portions of the coil. The result is a very flat BL curve and capability of high excursion, but there are a lot of issues that plague the design. One is that you will lose overall BL due to having to space the coil further from the gap to have clearance for the added layer(s), and you have higher mass and higher inductance due to the added coil. You also have the cost of added coil. When you get lower BL, higher mass, and higher inductance, efficiency of the driver and transient performance suffers, which is the major complaint of the first LMT designs in the aspect that they are very, very power hungry. There are ways to aid the problems with the design, but most will add to other problems no matter how you slice it. Example, you could copper plate the polepiece to shunt out eddy current and lower inductance, but that is going to drop BL even further and increases cost. If you wanted to up the BL, that is going to require more motor, thus more cost. TCs motors are long coil, shorter gap designs, and that applies to the designs they're using now. These long coils (especially high excursion performers like Eclipse Tis and Ti Pros) require dual mirrored spiders to keep themselves more linear at higher excursions since longer coils are more prone to rocking and damage from rocking, and will require more clearance from the motor to assure that it doesn't mechanically bottom out. That again is going to increase cost. You could make the motor a very good performer, but no matter which way you slice it, it isn't a cost effective alternative and likely won't be great for the average buyer as the sheer cost to make the driver will hinder it from being the top dog in it's price range. Of course, all designs can and will be improved, it just takes time.

Compliments of: http://forum.ecoustics.com/bbs/messages/4/151628.html

 

[ciaonzo 5,000+ posts]

Here's a visual to go with your post.

http://www.aranmaracoustics.com.au/New_ADIRE/X_68_Motor_Assy_Cut1.jpg

 

[Wingman0121 10+ year member]

I can't believe I just read all that. My brain is tingling.

 

[Kyle_Keating 10+ year member]

That write up is heavily misguided and old information (2005?), I have fea'ed both designs under a variety of variables and constants. The initial lure of XBL^2 was promises of ultra high sensitivity, flat BL and low inductance - in truth the only way to get that is the same way as always. You can't just get something for free.

The facts are this. They both are limited by the exact same math so there is little SPL or inductance advantage between the two designs.

They both can have either low or high inductance. If you don't double up the turns on the XBLL coil compared to the longer overhung or lms coil, you're sensitivity will be considerable lower. When you double the turns, you bring the inductance right back up. Same game, different name. Shorting rings can be applied inside the gaps, but this is no different than n undercut lms or overhung gap with a shorting ring in it.

Secondly they both have about the same sensitivity (LMS is not more power hungry) when you hold the xmax, magnet size, resistance and moving mass to a constant. XBLL is not more efficient than more motor designs, the very nature of the design makes it less efficient than an overhung coil that can move of equal xmax. Its not mathematically possible for it to be more efficient or even as efficient and here is why…

standard overhung motor (also works for lms coils)

equivalent XBLL motor with the same xmax limit. This design has a 50% shorter coil than the overhung design, but two gaps. There are two FEA models of this motor. 1 with the same gap width and number of layers as the overhung voice coil (4) and an (8) layer version with a wider gap but it has the same moving mass and resistance as the overhung example.

A quick glance shows the flux from the XBLL motor is divided between two gaps compared to the higher density single gap of the overhung/lms motor.

This coil is 9.3 ohms at a fixed length L and fixed gauge G

Here you can see the BL curve at a fixed power load for the overhung motor. Not very linear, but it is efficient.

This coil is 4.65 ohms at a fixed length L/2 and fixed gauge G

Here we can see the XBLL curve with the same power load. We can see it does have have nearly the same force, but it also has a less L because its coil is much shorter (50% exactly) The voltage was decreased for this model to match the power level of the overhung coil because the XBLL coil has 50% less resistance. If you don't match the power level you don't see the real sensitive difference. In this case we can observer XBLL is NOT very efficient, so we must increase the number of turns to bring up the L back to a normal level and gain back our sensitivity.

This coil is 9.3 ohms at a fixed length L/2 and fixed gauge G

The 8 layer example is much better, but surprisingly with the same L, same moving mass and same resistance, we STILL don't reach the maximum sensitivity of the non-linear overhung coil. We get pretty close, but we also forgo the lower inductance of the smaller coil because we beef'ed it back up again. But we do still maintain linear control which is good, but its NOT free.

Now lets look at 1 LMS example similar to the 4 layer XLLL example. The

This is one example of how to make an LMS coil from a 4 layer overhung coil - we cut out winding to linearize the L to counter the non-linear B (sort of like an inverse)

This coil is 7.4 ohms at a fixed length L/2 and fixed gauge G

You can see we have very fine control over the BL curve and it does produce very flat results, but holding the power constant we do lose sensitivity just as the XBLL coil. Also, like the 4 layer XBLL coil, we also reduce the resistance and therefore don't have the same moving mass or L comparable to the overhung coil. a 4 layer LMS coil is not entirly comparable to the 4 layer overhung coil (just as we saw with the XBLL examples) So we really need to beef up the LMS coil to the same moving mass. Mathematically this works out to a 5 or 6 layer LMS coil give or take and the results come out similar to the 8 layer XBLL coil with the exact same moving mass fixed to the same power load.

Here is our fixed resistive and fixed mass examples

We have to widen the gap by the width of 1 layer for the quasi-5 layer LMS example, this model does not quit show that, but its very close. In realitiy, the LMS coil would have just a tad lower force.

At the end of the day they are both about the same sensitivity (the XBLL may have a slight advantage but its much less than what is proposed by this author). Neither has an inductance advantage. There are examples of very low inductance LMS drivers as well as XBLL drivers. There are also examples of very high inductance XBLL drivers and LMS drivers (don’t pick specific examples for general comparisons because the variables involved are different in every application)

Dan Wiggens has done a good job selling his story about higher sensitivity and lower inductance, but looking at the math we can see that XBLL does linearize the BL, but at the same scarifies that LMS has (and split coil for that matter). It will not beat a straight overhung coil at the same xmax.

 

[dkdub 10+ year member]

In a nutshell... xbl^2 is nice //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif that is if you aren't looking for the typical insane output that so many on this forum go nuts for.

 

[whitedragon551 5,000+ posts]

That write up is heavily misguided, I have fea'ed both designs under a variety of variables and constants.
The facts are this. They both are limited by the exact same math so there is little SPL or inductance advantage between the two designs.

They both can have either low or high inductance. If you don't double up the turns on the XBLL coil compared to the longer overhung or lms coil, you're sensitivity will be considerable lower. When you double the turns, you bring the inductance right back up. Same game, different name. Shorting rings can be applied inside the gaps, but this is no different than n undercut lms or overhung gap with a shorting ring in it.

Secondly they both have about the same sensitivity (LMS is not more power hungry) when you hold the xmax, magnet size, resistance and moving mass to a constant.

Aside from this does the above quote seem pretty spot on as far as good information goes?

In a nutshell... xbl^2 is nice //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif that is if you aren't looking for the typical insane output that so many on this forum go nuts for.

SPL is puke. SQ FTW! Its all about reproduction, transparency, blending, flat response curve, etc.

 

[ciaonzo 5,000+ posts]

SPL is puke. SQ FTW! Its all about reproduction, transparency, blending, flat response curve, etc.

BOO!! HISS!!! Mad... can't get loud.
Therefore a witch!

lol

 

[whitedragon551 5,000+ posts]

I just remembers something. Robot Underground has Adire's site up for sale on eBay and they have Adire's database posted. I downloaded the Adire tech sheets for alot of stuff. That "stuff" just happens to have the XBL^2 tech papers, detail papers, graphs, diagrams, and the executive summary composed by Adire. Im sure someone in this thread will be interested in reading this information.

XBLTech.rar

 

[Kyle_Keating 10+ year member]

edited my post to include math, read above, and don't believe the hype. Im not out to prove one is better than the next, just separate the myths from reality.