Introducing the Luna Mini Monitor!

[N Boros]

I would love an MTM sierra-2 center channel, but it turns out the larger woofer sized woofers would cause lobing interference and it wouldn't sound that good.

The Ascend CMT 340 is available in a center channel MTM design and I haven't heard others mention issues of lobing. If the crossover is altered to take this into account, then an MTM doesn't have to have lobing, or it can an least be greatly reduced. From what I understand the MTM design from most manufacturers are just not designed well and this is why the issue crops up.

[davef]

The Ascend CMT 340 is available in a center channel MTM design and I haven't heard others mention issues of lobing. If the crossover is altered to take this into account, then an MTM doesn't have to have lobing, or it can an least be greatly reduced. From what I understand the MTM design from most manufacturers are just not designed well and this is why the issue crops up.

The issue with a dual woofer MTM Sierra-2 is really about what actual performance benefits it would have over a single woofer version and if it would be worth the extra $$$. As it stands now - the custom RAAL ribbon and the custom 6" SEAS Curv woofer have both been specifically designed to work together to maximize performance. Adding a second woofer in an MTM design really doesn't improve performance - it would actually limit horizontal dispersion (if used horizontally) The only advantage would be an improvement to efficiency and dynamics (in the bandwidth of the woofer) for which the S2 tweeter would not be able to match.

To truly take advantage of having the additional woofer, we would need to use our 70-20xram ribbon, which would bring the costs to basically the same as our Horizon, with the Horizon still offering better performance.

Dual woofer MTM Luna (as a center) will provide very similar performance to the Sierra-2 in a very compact form factor (only 5.75" high) and would make for an ideal center with Sierra-2 as left / right.

We certainly could manufacture an MTM Sierra-2, but I honestly do not see the point as it would be a considerably larger and more expensive speaker than the Sierra-2 and it would not provide better performance. We would need to upgrade the tweeter as well...

Hope this makes sense

[KevinC39]

Yep, that makes perfect sense actually. Thanks for the explanation.

[diesel79]

The Luna Center sounds like it is going to be a special little speaker! Can’t wait to see it.

[N Boros]

The issue with a dual woofer MTM Sierra-2 is really about what actual performance benefits it would have over a single woofer version and if it would be worth the extra $$$. As it stands now - the custom RAAL ribbon and the custom 6" SEAS Curv woofer have both been specifically designed to work together to maximize performance. Adding a second woofer in an MTM design really doesn't improve performance - it would actually limit horizontal dispersion (if used horizontally) The only advantage would be an improvement to efficiency and dynamics (in the bandwidth of the woofer) for which the S2 tweeter would not be able to match.

To truly take advantage of having the additional woofer, we would need to use our 70-20xram ribbon, which would bring the costs to basically the same as our Horizon, with the Horizon still offering better performance.

Dual woofer MTM Luna (as a center) will provide very similar performance to the Sierra-2 in a very compact form factor (only 5.75" high) and would make for an ideal center with Sierra-2 as left / right.

We certainly could manufacture an MTM Sierra-2, but I honestly do not see the point as it would be a considerably larger and more expensive speaker than the Sierra-2 and it would not provide better performance. We would need to upgrade the tweeter as well...

Hope this makes sense

That does make sense. Thanks.

I have a follow up question along the same lines. When the Sierra 2 is used as a center horizontally with the tweeter rotated 90 degrees, it too will have a more limited horizontal dispersion simply because there is a wider baffle. Right?

Is is possible for the Luna center to have similar horizontal dispersion as the Sierra 2, or would the MTM design be holding it back in some way? How would the horizontal dispersion compare with the Horizon center? The Horizon is probably a little bit wider, but it has the vertical tweeter over midrange which should help maintain good horizontal dispersion.

[mikesiskav]

Ah yes, I forgot about the cost for performance aspect of it. That being said there would be more lobing on a Sierra-2 MTM vs the 340se due to the higher crossover needed for the Sierra-2 tweeter. Using the RAAL from the Towers/Horzion would fix that problem since it can be crossed over much lower. If such a speaker could be produced for lower cost than the Horizon, I think there could be a market for it. Of course performance would not be as good as the Horizon. But for me, the Horizon is just too big.

[davef]

That does make sense. Thanks.

I have a follow up question along the same lines. When the Sierra 2 is used as a center horizontally with the tweeter rotated 90 degrees, it too will have a more limited horizontal dispersion simply because there is a wider baffle. Right?

Is is possible for the Luna center to have similar horizontal dispersion as the Sierra 2, or would the MTM design be holding it back in some way? How would the horizontal dispersion compare with the Horizon center? The Horizon is probably a little bit wider, but it has the vertical tweeter over midrange which should help maintain good horizontal dispersion.

Baffle width affects diffraction - it has minimal effect on dispersion. Sierra-2 (used a horizontal center)has very wide horizontal dispersion but the further you get off-axis, the less symmetrical the response becomes such that at (for example) 45 degs off to the left might sound slightly different compared to 45 degs off to the right. A horizontal MTM has more limited horizontal dispersion, but the response is symmetrical. Of course, the actual room will considerable influence on this...

The Horizon, being a WT/MW design is the best of both worlds with exceptionally wide and symmetrical horizontal dispersion.

[jimb]

The issue with a dual woofer MTM Sierra-2 is really about ...

Dual woofer MTM Luna (as a center) will provide very similar performance to the Sierra-2 in a very compact form factor (only 5.75" high) and would make for an ideal center with Sierra-2 as left / right.

...

With my new Lunas, this could become interesting to me. So, the main reason to use a "center" Luna versus a center S2 would be the narrower cabinet (less height), right? How might the cost of a center Luna compare to the cost of a center S2?

If the mains are already "only" Luna, what if any advantage would there be to a center Luna versus a standard Luna on its side with rotated tweeter? (I think a rotated tweeter is an option?) Could I buy a single Luna?

[sdg4vfx]

... If the mains are already "only" Luna, what if any advantage would there be to a center Luna versus a standard Luna on its side with rotated tweeter? (I think a rotated tweeter is an option?) Could I buy a single Luna?

Is rotating the tweeter an option on the standard Luna? (I.e for use as a center speaker on it's side.)

Dave explained that a S2 on it's side has healthy horizontal dispersion but some loss of symmetry in the response. How would a Luna on it's side perform?

[davef]

Is rotating the tweeter an option on the standard Luna? (I.e for use as a center speaker on it's side.)

Yes -- and it is simple just like the S2 (we use the exact same tweeter cutout etc.)

Dave explained that a S2 on it's side has healthy horizontal dispersion but some loss of symmetry in the response. How would a Luna on it's side perform?

Quite well actually, slightly wider horizontal dispersion compared to the S2 on its side due to the Luna having a smaller woofer and closer tweeter/woofer spacing.