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Ascend Sierra Luna Mini-Monitor Review

Shazb0t

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It seems to me something else could be at play because like I said the 70-20 in the Ascend towers isn't that wide of dispersion but since your listening tests show them to sound more spacious it's possibly because they are smoother off-axis and simply more neutral tweeters. Also, if wide dispersion was so important then you would think the 64-10 would be the best RAAL offering but I don't think I've ever heard someone claim to prefer it over the 70-20 which is more evidence to me that it's really neutrality, both on and off-axis, that is responsible for the preference.
I think what you're missing is that although the 64-10 is a wider dispersion tweeter it has to be crossed over much higher in the frequency range than the 70-20. This gives speakers that employ the 70-20 the advantage of wide dispersion in the upper mids and in the treble without a crossover point in the frequency range where our hearing is the most sensitive. It also allows for better directivity integration with a midrange that hasn't started to beam yet. When you look at the 70-20 RAAL Towers against some other popular dome tweeter speakers in their price range they have significantly higher off-axis SPL from the midrange through to the treble while maintaining a smooth directivity. I think that is the real advantage of a tweeter which can crossover at a much lower frequency while also maintaining relatively low distortion. This appears to also be the strategy used by multi-way benchmark speakers like the Salon2.
 

aarons915

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I think what you're missing is that although the 64-10 is a wider dispersion tweeter it has to be crossed over much higher in the frequency range than the 70-20. This gives speakers that employ the 70-20 the advantage of wide dispersion in the upper mids and in the treble without a crossover point in the frequency range where our hearing is the most sensitive. It also allows for better directivity integration with a midrange that hasn't started to beam yet. When you look at the 70-20 RAAL Towers against some other popular dome tweeter speakers in their price range they have significantly higher off-axis SPL from the midrange through to the treble while maintaining a smooth directivity. I think that is the real advantage of a tweeter which can crossover at a much lower frequency while also maintaining relatively low distortion. This appears to also be the strategy used by multi-way benchmark speakers like the Salon2.

That is a good point but remember the 70-20 is used in a 3 way in the Sierra tower so the lower crossover point isn't as necessary. It would be much more useful in a 2-way speaker but since it's also a lot more expensive you usually only see them in higher priced speakers like the Sierra towers with RAAL. The 64-10 needing to be crossed over at 3k minimum lends itself better to a 3 way speaker and you do see that in many of Dennis' designs. All I was really saying is that most people claim the 70-20 sounds much better than the 64-10/70-10 RAAL offerings yet doesn't have nearly as wide of dispersion, it's an interesting case study in the wide dispersion argument.
 

Chromatischism

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I think what you're missing is that although the 64-10 is a wider dispersion tweeter it has to be crossed over much higher in the frequency range than the 70-20. This gives speakers that employ the 70-20 the advantage of wide dispersion in the upper mids and in the treble without a crossover point in the frequency range where our hearing is the most sensitive. It also allows for better directivity integration with a midrange that hasn't started to beam yet. When you look at the 70-20 RAAL Towers against some other popular dome tweeter speakers in their price range they have significantly higher off-axis SPL from the midrange through to the treble while maintaining a smooth directivity. I think that is the real advantage of a tweeter which can crossover at a much lower frequency while also maintaining relatively low distortion. This appears to also be the strategy used by multi-way benchmark speakers like the Salon2.
And that goes for any tweeter type. The Buchardt S400 MKII will be interesting – they dropped the crossover from 2670 Hz to 1800 Hz. I imagine it will see a lot of the upper midrange/lower treble fill-in effect you describe. And the tweeter distortion was lower than the RAAL; it will be interesting to see if that is still the case with the increased load it is taking on. Both are great.
 

Shazb0t

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That is a good point but remember the 70-20 is used in a 3 way in the Sierra tower so the lower crossover point isn't as necessary. It would be much more useful in a 2-way speaker but since it's also a lot more expensive you usually only see them in higher priced speakers like the Sierra towers with RAAL.
I understand what you mean, but I would imagine that it's easier to make bass drivers that only have to play up to ~500hz along with a dedicated midrange that only has to cover ~500-2000hz have better distortion, linearity, and maximum SPL limits than a single driver covering all of that range. It's also likely to allow the speaker designer to have more precise directivity control of the speaker through the ability to chose different driver sizes and characteristics for each application.

All I was really saying is that most people claim the 70-20 sounds much better than the 64-10/70-10 RAAL offerings yet doesn't have nearly as wide of dispersion, it's an interesting case study in the wide dispersion argument.
I think that's its also fair to attribute some of that to the lower distortion, better linearity, and higher power handling that the 70-20 has over the other two. As far as I'm aware RAAL believes and markets their 70-20 as the superior tweeter.
 
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Dennis Murphy

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That is a good point but remember the 70-20 is used in a 3 way in the Sierra tower so the lower crossover point isn't as necessary. It would be much more useful in a 2-way speaker but since it's also a lot more expensive you usually only see them in higher priced speakers like the Sierra towers with RAAL. The 64-10 needing to be crossed over at 3k minimum lends itself better to a 3 way speaker and you do see that in many of Dennis' designs. All I was really saying is that most people claim the 70-20 sounds much better than the 64-10/70-10 RAAL offerings yet doesn't have nearly as wide of dispersion, it's an interesting case study in the wide dispersion argument.

I haven't seen the posts claiming the 70-20 sounds better than the 64-10 or 70-10, so I don't know what was being held constant. I've stated on several occasions that I don't think the 64-10 is the best candidate for most 2-way designs, which is why I only use it in 3-ways crossed at around 3800 Hz. The 70-10 is good down to about 2700 Hz, but that's still too high for optimal performance in a 2-way unless the woofer is very small. Properly implemented, I think the 64-10 provides superior performance to the 70-20 above 3800 Hz, and it actually has lower distortion in its newest "X" incarnation than either the 70-20 or 70-10. Not that I think this really matters at rational playback levels.
 

abdo123

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@thewas is right with his point of view, because once the individual drivers have been carefully and reliably measured, there is no need for further measurements during crossover development - apart from the finished product, of course.
The crossover simulation software is so good that the simulated frequency responses are almost identical to the measured ones.

Only if structural changes are made to the speaker (rounding of the side edges, BR port change,...), then a re-measurement of individual or all drivers may be necessary and then it is indeed as you say that the NFS makes life much easier.

I'm going to be frank but your response kind of indicates that it's easy to design a speaker. When in reality the majority of brands offer mediocre designs at best.

Are they taking us for fools or does having an NFS or an anechoic chamber in your backyard makes a difference?

I feel like whenever a designer makes an 'assumption' it compromises the design, so does inadequate measurement conditions.

The NFS solves both of these issues in my opinion. since you can afford the luxury of measuring at every single point in development you don't have to guess why or where things went wrong. and that in its own way is priceless for a big brand.
 

PKAudio

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There are changes during speaker development phase that require remeasuring the drivers, or at least impedance measurement to confirm change of bassreflex tuning etc. And there are changes that does not require remeasurement.
Remeasurement needed if:
- there is the change of driver for different model
- any front baffle change happened
- any driver position changes
- front baffle tilt change
- port tuning, damping, etc changed

And when not needed:
- any crossover change as this is clearly visible in crossover SW (Vituix etc.)

There is really no need to remeasure in development phase when I just need to change for example resistor in tweeter crossover to change treble level. This is evaluated by ears by listening.

Of course, when the design is finalized, one needs to measure the final result to get golden sample data, data for web presentation, etc.
 

ahender

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Hats off to the guys at Ascend for their response to this review. Some companies deny negative analytical info and double down on the marketing speak and snake oil (you know these companies). I’m glad the folks at Ascend hit it head-on and fixed the speakers in question. This is what good companies do, no excuses, just action.

Side note, I heard their larger models with the RAAL tweeters and was very impressed. Was surprised to see the poor performance of these but it sounds like the 2.0 version is a major improvement. Impressed by their response.
Dave has said a Duo V2 upgrade kit will be available soon for a reasonable price. As an owner, I’m glad.
 

Colonel7

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Well I agree that nulls this narrow are never audible to me. Peaks, however, are occasionally audible, and that's the main thing being addressed here. Just this week I was dealing with a very high Q peak that stuck out like a sore thumb when practicing on my digital piano. Not sure if it was from my room, the speaker, or even the piano sample itself (possibly a combination!) but it was always the same note, and only one of the various piano VSTs seemed to trigger it, but it was driving me nuts because I kept hitting that note in the specific piece I was practicing. Ended up reducing it by like 10 dB.
Agree with both your posts on once hearing a resonance it is jarring and won't ever be unheard, especially on piano where there is no place to hide. The arrival of piano in Unsquare Dance in a set of speakers I own is very resonant, probably high Q but it is there nonetheless, on a song I really like.
 

RMW_NJ

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Upgrade kits are now available:

 

snackiac

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Can anyone speculate on the effectiveness of the upgrade kit? It's surprising to me that a user installable mod can clean it up so much. He does have Klippel measurements supporting the upgrade though, so it must be workable, right?
 

JLGF1

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I'm not clear what you mean by "clean it up so much"? Or what you mean by workable?

I would expect the optimized xover benefits to be tangible, but subtle as has been reported with the optimized Sierra-EX-V2 xover upgrade.
 

RMW_NJ

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Can anyone speculate on the effectiveness of the upgrade kit? It's surprising to me that a user installable mod can clean it up so much. He does have Klippel measurements supporting the upgrade though, so it must be workable, right?
Judging by the before and after Klippel measurements, the upgrade seems to be a pretty substantial improvement.
 

snackiac

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I'm not clear what you mean by "clean it up so much"? Or what you mean by workable?

I would expect the optimized xover benefits to be tangible, but subtle as has been reported with the optimized Sierra-EX-V2 xover upgrade.
Sorry, good point. From my very amateur perspective the measurements look substantially better after the upgrade, and I'm just surprised a user mod could have that effect. Especially the issues with the cabinet. I guess I'm just looking for someone to say "yeah the modifications listed could definitely result in that kind of improvement in the Klippel measurements", and there is no other measurement goofiness going on.
 

JLGF1

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The three main parts of a (passive) speaker are: 1) drivers 2) xover 3) cabinet (including port)

In following the upgrade, the xover is being replaced (just a board screwed into the cabinet).

The cabinet response is being modified with damping material and physical port adapters.

No reason a handy end user cannot accomplish that with the upgrade kit. It's fairly simple.

Note: the audible resonance issue only manifested itself at very high volume levels.
 
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