Starting to really dislike LR4 crossovers!

[Dennis Murphy]

Let me play devil's advocate here. Let's say you're essentially correct. Assuming you're talking about the RAAL, how can you be sure that the superior realism isn't related more to its dispersion characteristics rather than say the oft stated decay characteristics? If so, maybe other sorts of planar tweeters might also prove to be similarly difficult to tell apart.

I'm not sure you're being much of a devil here. I never stated why I thought the RAAL sounded more realistic to me on program material with lots of energy at the top of the audible band. Could be decay. Could be dispersion (although it's not that much wider than the 0W1 3/4" dome, which doesn't sound like the RAAL). Could be the launch wave resembles more a line source than a point source. I don't know. (BTW--the RAAL isn't a planar, although it sounds like you're grouping it with planar devices. Maybe your sentence is just ambiguous on that point.)

 

[TheStalker]

I'm not sure you're being much of a devil here. I never stated why I thought the RAAL sounded more realistic to me on program material with lots of energy at the top of the audible band. Could be decay. Could be dispersion (although it's not that much wider than the 0W1 3/4" dome, which doesn't sound like the RAAL). Could be the launch wave resembles more a line source than a point source. I don't know. (BTW--the RAAL isn't a planar, although it sounds like you're grouping it with planar devices. Maybe your sentence is just ambiguous on that point.)

I personally find the RAAL a bit dead and flat sounding. Lacking in micro information. I find the OWII to be an overall much more exciting tweeter. And Esotar 2, Scanspeak Beryllium, Focal Beryllium, B&W diamond to be on another level better. Those have an incredible retrieval of micro information and clarity. And they do it without sounding overly bright. On the contrary, they are extremely pleasing and addicting, making the ear want more and more and more.

Don't get the RAAL hype.

 

[Chu Gai]

I'm not sure you're being much of a devil here. I never stated why I thought the RAAL sounded more realistic to me on program material with lots of energy at the top of the audible band. Could be decay. Could be dispersion (although it's not that much wider than the 0W1 3/4" dome, which doesn't sound like the RAAL). Could be the launch wave resembles more a line source than a point source. I don't know. (BTW--the RAAL isn't a planar, although it sounds like you're grouping it with planar devices. Maybe your sentence is just ambiguous on that point.)

I speculated on decay since that's often been offered as an explanation by people. I'm just trying to get a better handle on if you've given serious thought and maybe run some experiments to try and determine the principal factor(s) that are at play. So, the vertical dispersion of the RAAL resembles that of a more conventional tweeter. And please look at my being somewhat contrary in the spirit of trying to foster a friendly discussion. Along those lines, I've sometimes wondered why, if the RAAL is so good, aren't speakers designed with it just totally smoking competition way above their price point? Lastly Dennis, just what do you consider music with lots of energy at the top of the audible band?

 

[Dennis Murphy]

I speculated on decay since that's often been offered as an explanation by people. I'm just trying to get a better handle on if you've given serious thought and maybe run some experiments to try and determine the principal factor(s) that are at play. So, the vertical dispersion of the RAAL resembles that of a more conventional tweeter. And please look at my being somewhat contrary in the spirit of trying to foster a friendly discussion. Along those lines, I've sometimes wondered why, if the RAAL is so good, aren't speakers designed with it just totally smoking competition way above their price point? Lastly Dennis, just what do you consider music with lots of energy at the top of the audible band?

Hi. I didn't construe your post as unfriendly--I just didn't think you were living up to the definition of a devil's advocate. The sound of the RAAL isn't that much different from other good ribbons. All the ribbons I've used have had less of a sssssssssssssssss quality to them than the typical dome driver. The difference seems to be around 6 kHz, and doesn't show up in a standard frequency response curve. A ribbon sounds to me like someone has stretched out the response of a dome, and the result is a less intense, more open treble sound when there is a lot of energy in the 6 kHz range. (Don't hold me to the exact frequency) The difference is immediately apparent on cymbals and triangles, and to a lesser degree on high violin passages. That's based on instantaneous, volume-compensated switches between the dome and the ribbon. The RAAL just has more of this quality, with other ribbons being in between the RAAL and the dome. Since I can't find any explanation for this in the frequency response plots, and there are a lot of domes with good decay performance, so that's why I've speculated that it may have something to do with the wave launch. But I dunno.

 

[Swerd]

All the ribbons I've used have had less of a sssssssssssssssss quality to them than the typical dome driver. The difference seems to be around 6 kHz, and doesn't show up in a standard frequency response curve. A ribbon sounds to me like someone has stretched out the response of a dome, and the result is a less intense, more open treble sound when there is a lot of energy in the 6 kHz range. (Don't hold me to the exact frequency) The difference is immediately apparent on cymbals and triangles, and to a lesser degree on high violin passages.

I borrowed terms from Interactive Frequency Chart - Independent Recording Network for sounds around ~6 kHz. I could find cymbals and violin, but not triangles. Maybe some of these terms and frequency ranges may help this conversation.

In General:
High Frequencies 6kHz – 20 kHz
Brightness / Crispness
Not enough is “dull” or “flat”
Too much 6-8 kHz is sibilant
Too much 8-10 kHz is brittle
Sensed more than heard above 16 kHz

Cymbals / Hi-Hat:
Clang ~200 Hz
Presence ~3 kHz
Shimmer 7.5 – 12 kHz

Violin:
Fundamentals G3-E6 (200 Hz – 1.3 kHz)
Fullness ~240 Hz
Formants 300 Hz, 1 kHz & 1.2 kHz
Overtones up to 16 kHz
Notes scratchiness at 7-10 kHz

 

[cschang]

Here's what David Fabrikant described in his comparison measurements of the RAAL 70-20XR and Ascend's NrT tweeter.

Notice that nearly all energy from the tweeter is fully dissipated between 0.39 msec and 0.59
msec. Nearly equal decay time throughout the full bandwidth of the tweeter results in a more
cohesive and detailed performance, closer to how sound is produced in nature. For example, a 2
kHz note dissipates at nearly the same time as a 30 kHz note. I believe that it is this remarkable
transient “speed” and uniform decay times that correlate to listeners describing the ribbon sound
as being more delicate and transparent.

The measurements are here:
http://www.ascendacoustics.com/pages/products/speakers/SRT/Ascend Sierra Ribbon Tower.pdf

 

[Dennis Murphy]

Here's what David Fabrikant described in his comparison measurements of the RAAL 70-20XR and Ascend's NrT tweeter.



The measurements are here:
http://www.ascendacoustics.com/pages/products/speakers/SRT/Ascend Sierra Ribbon Tower.pdf

That's very interesting. A lack of hangover could be what I'm hearing. It makes intuitive sense since the ribbon's mass is so low. On the other side of the ledger, ribbons have higher harmonic distortion than most domes, particularly in the lower treble. I guess it all comes down to what differences are really audible. In any event, I'm sticking with ribbons for my speakers.

 

[TheStalker]

That's very interesting. A lack of hangover could be what I'm hearing. It makes intuitive sense since the ribbon's mass is so low. On the other side of the ledger, ribbons have higher harmonic distortion than most domes, particularly in the lower treble. I guess it all comes down to what differences are really audible. In any event, I'm sticking with ribbons for my speakers.

So Dennis, what's your take on shallow slope crossovers?

 

[Dennis Murphy]

So Dennis, what's your take on shallow slope crossovers?

My take is that 1st order acoustic crossovers aren't worth the cabinet and component complexity, or the off-axis lobing problems they create--not to mention the narrow choice of drivers that can handle 6 dB roll offs over a wide frequency range. The choice between 2nd and 4th order depends on the drivers and where the cross is taking place. Either can produce excellent results if the application is appropriate. People get too hung up on audio religion. If it sounds good, it is good.

 

[ichigo]

Here's what David Fabrikant described in his comparison measurements of the RAAL 70-20XR and Ascend's NrT tweeter.



The measurements are here:
http://www.ascendacoustics.com/pages/products/speakers/SRT/Ascend Sierra Ribbon Tower.pdf

The Esotar 2 (a silk dome) isn't that far off though, the RAAL 70-20XR stops at about 0.8 msec throughout the audible range while the Esotar 2 stops at about 1.0 msec or so, is 1/500th of a second of decay really audible?