I agree with everything Dennis posted... The RAAL ribbons have superb horizontal dispersion. Vertical dispersion is more limited then a dome but this can be quite beneficial for a loudspeaker that will be used at or near ear-level as high frequency reflections off the floor and ceiling will be greatly reduced -- thus you hear more direct sound and less of the environment. It is not only that horizontal dispersion is "wide" -- but it is extremely linear with a gentle and consistent roll off, which is ideal.
Originally Posted by brannigan
Can anyone confirm that RAAL 70-20XR ribbon tweeter that ascend acoustics uses has overcome the narrow sweet spot of most ribbons? The way they describe it, it seems to have great dispersion, or off axis performance, if I'm using the right words. Sorry if my terminology is off. I'm not a speaker scientist. The words they used were "accurate off-axis response free of bloom".
Bloom looks something like this and is typical with a dome
Look at the relative increase in energy in the 2.5 kHz - 5.5 kHz range.
As compared to the polar response of our RAAL equipped tower
Each line across the graphs represents the frequency response at 5 degrees off-axis, from 0 degrees to a full 90 degrees off-axis. The polar response of the Sierra Tower with RAAL is exceptional. Note: our polar response only shows one direction as compared to the graph from Stereophile. The reason for this is that the Sierra Tower has a horizontally symmetrical driver arrangement and off-axis to the right will look the exact same as off-axis to the left. By only displaying one direction, we are able to get a closer look at each individual off-axis response.
Originally Posted by 6SpeedTA95
I registered over there Thursday or Friday, still can't post, I e-mailed Dave....I'm going to post some of my questions over there
Have you been able to post? Have I responded?
Originally Posted by cschang
There has been a rash of spam posts there lately, so I think there is a delay in confirming registrations to weed those types out.
You said it, I can't believe how many spammer registrations we have been getting recently. Most are now coming from a .NZ domain, whatever that means
Originally Posted by AudioFyle
Well, as I said in my original reply, in my opinion the RAAL ribbons are the current best-of-breed. These drivers have addressed many of the dispersion issues. However, while the current iteration of the RAAL tweeters have significantly improved vertical dispersion, horizontal dispersion still remains problematic.
Also, the 70-20XR is not their flagship driver. The 70-10 is. It can handle peak SPLs that would blow other ribbons out of the gap. That said, the 70-20XR is still a very fine driver.
Dennis is correct. The 70-20XR is actually RAAL's flagship 70mm length ribbon. It is more expensive than the 70-10 and is only available to OEM's. We chose it because it can be crossed lower and has superior dynamics and power handling below 4kHz, as well as a flatter response not requiring the use of the acoustic foam pads. Think about it for a minute, the 70-10 is 70mm high x 10mm wide while the 70x20 is 70mm high x 20mm wide (twice the radiating area) That said, these are exceptional tweeters and simply the finest I have ever had the pleasure of working with. I am also equally impressed in the consistency from one unit to another - and from production batch to production batch.
We have also only had one tweeter fail in a customer’s home and after examination, we found that a small metal fragment slipped thought the protective screen and creased the ribbon.
As I am sure Dennis will agree, these tweeters are not hype – I had my own doubts until I evaluated them, these are the real deal guys…