Coming in late August 2018
LSA (Living Sounds Audio) is proud to introduce the new LSA 10 loudspeakers. Upgrading the original LSA speakers was our goal with the intro of this new line. Reviews of the original LSA-1 and LSA-2 speakers were all excellent and they set a performance standard in their price ranges. Our goal was to set a new standard in affordable Internet Direct loudspeakers and compete with far more expensive products. To that end we gave Dan Wiggins and his team a free hand in the design with their mission being to offer far more value than the original speakers. These new models go lower have better dynamics and image better, while keeping the LSA legendary musicality with greater resolution. The new LSA-10 Statement raises the bar in affordable state of the art monitor and competes with more expensive high-end speakers at factory direct pricing. Our goal was to outperfporm our favorite $7,750.00 monitors. We think we have accomplished this goal and are extremely proud of these new speakers
The new LSA custom speakers use Dan’s patented XBL2 Motor structures to lower distortion with greater bass extension and midrange/high frequency resolution. The XBL2 Motor structure reduces low frequency distortion by keeping a linear BL even at high output levels. X-max (woofer excursion) is significantly increased as well for greater bass extension in smaller boxes.
The LSA10 Statements come in a beautiful upgraded ebony lacquer gloss finish.
The LSA-10 Statement monitor uses a custom LSA 1” copper beryllium dome tweeter with a compact neodymium XBL2 magnet structure and a shallow waveguide to better integrate with the woofer, a single custom LSA black anodized aluminum 6.5” XBL2 woofer, and a single rear mounted 5” x 7” sub bass radiator. Other standard upgrades include a sophisticated 8th order linear phase acoustic crossover topology with state of the art crossover components and OCC internal cable. Upgraded binding posts are of red copper. The LSA-10 Statement has an in-room response from 35 Hz to 30 kHz +/-3Db, an 88Db sensitivity and a 6-ohm rating. The LSA-10 Statement uses a magnetically attached grille. Projected retail is $3,495.00/pr
Rendering shown on optional stands. Actual speaker will be hi-gloss black ebony
Optional custom stands are $399.00/pr
Preliminary specifications that are subject to change
LSA speakers are sold Factory Direct without dealer profits at www.underwoodhifi.com
Call Walter at 770-667-5633 to discuss any of the above
What is XBL² technology?
A speaker is essentially two magnets, pushing and pulling on each other. There's a static magnet and an electromagnet. The static magnet is the big stack you're used to seeing - the permanent magnets in the motor. The electromagnet is the voice coil. When you put a current through a coil, it sets up a magnetic field; the direction and strength of that magnetic field depends upon the direction and magnitude of the current. And the more windings that the current flows through, the stronger that magnetic field is.
The actual force - BL - is the integral of the flux over the voice coil. Basically add up all the flux that is passing through the voice coil and you get the BL. It's not a "flux in the gap times the length of wire" type approach, because flux is everywhere - in the gap AND outside the gap. It is weaker (and falls to essentially zero) outside the gap, but is still quite potent. And in fact, you can have up to 50-60% of the total flux in the system reside not in the gap, but outside the gap, or what is called the fringe field.
So we see that the actual motor works by the dynamic magnetic field set up by the voice coil interacting with the static magnetic field set up by the permanent magnet, and that the total field is the field in the gap and the fringe field. And the fringe field can be a significant contributor of the total flux in the system, so much so that you cannot ignore this field; the way the fringe field is integrated by the voice coil is critical, especially when looking to make this total integral constant over multiple locations (flat BL curve).
XBL² works by splitting the static field into two parts. Then you have a voice coil designed so that equal amounts of the voice coil sit - at rest - in each of the fields.
As the voice coil moves up, some of it leaves the lower field, but an equal amount enters the upper field, meaning that you have a net zero loss/gain in flux over the voice coil, so the total flux integrated by the voice coil is constant. We also optimize the length of the voice coil and/or the depth of the rebates so that the fringe field between the gaps (inside the rebates) is roughly equal to that outside the gaps. This makes the total integration of the voice coil constant.
And in fact, it will be constant until the voice coil starts to leave both gaps. In the image shown, imagine the voice coil moving up. Some leaves the lower gap, and an equal amount enters the upper gap. Keep moving up, and the voice coil ends above the top plate and in the rebate, and completely covers the upper gap. Once the lower end of the voice coil starts to enter the upper gap do we start to lose BL - the integration is no longer constant. This is how you get such long stroke - you have to completely leave one gap, and start leaving the next before you start to lose motor force.
The advantages of XBL² are pretty self-evident:
1. Short voice coil, meaning low moving mass. This is not always required, but it's always easier to add mass to a driver than to remove it! Having a lower starting point in terms of moving mass is a huge benefit, because mass is your biggest enemy in terms of efficiency.
2. The short voice coil also means fewer turns, which means lower inductance. Inductance is the prime limiter in terms of extension on the top end of a speaker. You may not need extension to 10 kHz, but it's a lot easier to get there if you have low inductance!
3. Low inductance also means low flux modulation. Remember about the strength of the magnetic field relying on the number of turns? Well, the number of turns dictates the inductance as well. The lower the inductance, the fewer the turns. And for a given BL, if you can lower the number of turns, that means you're using more of the static B to generate the force. Which means the total force changes less with power applied (since the total force is a combination of the static field AND the voice coil's dynamic field).
4. Tolerance to production errors. The crucial dimensions in an XBL² motor are the sizes and position of the gap. Since these are either cut or forged in to the steel, it's pretty simple to get them accurate and repeatable. Errors in the critical dimensions are naturally pushed to the operations that are the easiest to control to tight tolerance - machining and forging.
5. Lower production cost. It should be obvious that the voice coil is cheaper - it's short. Less copper means lower price. But also with short voice coils come easier times with gap widths. You don't need as wide a gap to accomodate the voice coil. Why? Rocking. For a given angular deflection (rock),there's less radial (in and out to the side) deflection of the end of the voice coil.
6. Overall motor size. We see that since the voice coil is ENTIRELY within the height of the top plate, we can use a short stack of magnets. No need for huge stack heights, unless you want them from a cosmetic standpoint. And because we're always integrating more than 50% of the total motor flux (one full gap plus fringe around it; usually we integrate 70% of the total flux in the system),we don't need a huge diameter magnet, either.