@DDF @Dennis Murphy These ideas are interesting. I messed around with straws a little bit and they made a difference but overall did not make things better with my speaker. Have you (anyone) experimented with inserts into the port to create low-pass or notch filters? Here is a link to a patent which shows some ideas, and a sketch of one implementation:The old straw trick will reduce the organ pipe resonance with a slight reduction in tuning frequency, but has a couple other drawbacks: increase in acoustic resistance which lowers port gain and broadens its response, and the added flow resistance can also limit the maximum output before it becomes non laminar (chuffs earlier). All in all maybe not a bad tradeoff for a badly resonant port.
Paper straws will be good so they flex, similar in idea to KEFs lossy rubber section in their ports (strategically placed at resonance points vs distributed like a straw).
Another trick I've heard of but not tried is using a mylar sheet bent into an s and inserted in the port (attribution: Jon Risch).
@DDF @Dennis Murphy Have you (anyone) experimented with inserts into the port to create low-pass or notch filters....
Due to the ASR reviews of the Sierra Luna and Luna Duo, Dave from Ascend Acoustics has purchased a Klippel NFS and has used it to develop the Luna V2 and Luna Duo V2. Dave has posted his 5 part development story complete with spins from the Klippel here: http://forum.ascendacoustics.com/sh...h-center-Luna-S2-or-Horizon&p=66344#post66344
WOW, amazing results. Lots of respect to Dave from Ascend for making this big investment (buying a Klippel NFS) as a small indie speaker company, while many larger speaker companies still refuse to even publish any measurements, let alone NFS measurements.A long read but well worth it. Credit to Dave at Ascend for taking ASR's Klippel measurements seriously. This major advancement at Ascend Acoustics may never have happened if @amirm hadn't made his original investment in a Klippel and begun freely sharing results from many different speakers.
Or KEFYikes. Another data point for, "If you are planning to spend a decent amount of money, just buy Revels."
Yikes. Another data point for, "If you are planning to spend a decent amount of money, just buy Revels."
No, not always. Proof: Blind Listening Test - KEF R3 vs Ascend Sierra 2EXOr KEF
Bravo!WOW, amazing results. Lots of respect to Dave from Ascend for making this big investment (buying a Klippel NFS) as a small indie speaker company, while many larger speaker companies still refuse to even publish any measurements, let alone NFS measurements.
TLDR for others who don’t want to dive into that thread; Ascend Acoustics has purchased an NFS and is using it to design much improved speakers coming soon. Here is the plot they posted of the upcoming Luna V2:
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Horizontal plot:
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I’m totally with you. I was more joining in to the point that you can pick any revel or any kef and not really screw up.No, not always. Proof: Blind Listening Test - KEF R3 vs Ascend Sierra 2EX
Ascend’s preference for ultra wide beam speakers isn’t for everyone, but neither is KEF’s medium/narrow beam for everyone (as the results linked above show, where Ascend easily beats KEF in a blind test).
I do think Revel is a great default choice for most, however even Revel’s speakers below their flagship lines (PerformaBe, Ultima2) don’t necessarily beat Ascend (depending on which compromises are more or less important to you). Proof: Blind Listening Test - Revel F206 vs Ascend Sierra RAAL Towers
Ascend speakers aren’t perfect, but they competently achieve a very wide beam that you don’t get anywhere else at the price point. The Luna’s may not be Ascend’s best performing product, but now that Ascend owns a Klippel, I expect some amazing products coming up from them. And the Luna V2 (charts shown above) is one of the first examples of this.
True, a very interesting saga and well documented by Ascend. But, Dave is a very experienced speaker designer and, I assume, listener who knows what to listen for in an audio system. The fact remains, he didn't hear the port issue originally so does it really matter, especially so to an "average" music/HT user ?Absolutely! What he has done is quite admirable. Jim
True, a very interesting saga and well documented by Ascend. But, Dave is a very experienced speaker designer and, I assume, listener who knows what to listen for in an audio system. The fact remains, he didn't hear the port issue originally so does it really matter, especially so to an "average" music/HT user ?
Due to the ASR reviews of the Sierra Luna and Luna Duo, Dave from Ascend Acoustics has purchased a Klippel NFS and has used it to develop the Luna V2 and Luna Duo V2. Dave has posted his 5 part development story complete with spins from the Klippel here: http://forum.ascendacoustics.com/sh...h-center-Luna-S2-or-Horizon&p=66344#post66344
While I agree that the science of speaker design has been advanced by Ascend Audio's investigation into the port resonance, I'm not so sure that the customer community has directly benefited in the short-term. Yes, Ascend will come out with a 2.0 version of their Luna line but likely will expect a price increase due to the R/D expenditures. And to what end, only if I play a track that has a note ... ? Full disclosure - I had written off the Ascend Luna as a possible upgrade (based upon the ASR review) to my HT but will now reconsider the 2.0v but only if the expected price increase isn't objectionable.Yes, because it doesn't matter until you do hear it. Same with any narrow resonance. You might not ever notice it until you play a track that has a note at a specific frequency and then you can't ignore it. It's not that having some of these issues will automatically make a speaker bad, but it increases the likelyhood of creating an audible problem. It's similar to Toole's comments on distortion. It may not be an audible problem most of the time... Until it is.
What an amazing read, thanks for sharing. Not only for the new data, but for seeing the process behind the scenes and how such a flaw might have been missed.
This gives me the utmost respect for Dave. Most manufacturer would have just ignored such issues or made silent adjustments. With an NFS, I'm going to trust ascends measurements to a whole new level. With that ridiculously wide directivity these could end up being my ideal speakers...
And it's even more than that - it was only from certain angles, apparently. The likelihood that it would be heard seems really low.Yes, because it doesn't matter until you do hear it. Same with any narrow resonance. You might not ever notice it until you play a track that has a note at a specific frequency and then you can't ignore it.
My working thesis is that the ideal dispersion width depends on the room's dimensions and the placement of the speakers. Wider room, further from walls = you want wider. Smaller room or closer to walls = you want narrower. The goal would be to maintain the same ratio of reflected sound in each case. Constant reflectivity? At least that makes sense to me. I would love to see more research done on this.With that ridiculously wide directivity these could end up being my ideal speakers...
I don’t know where you are getting this idea that Ascend made bad speakers and suddenly now is making good ones with the NFS. I’ve owned all of Ascend’s speakers, and their Sierra 2EX and Sierra RAAL Towers are still IMO the best speakers available in their price range (for people who like wide dispersion), period.I don't understand why a experienced loudspeaker designer would really need a Klippel NFS to suddenly make well measuring loudspeakers. The NFS just makes measurements more fast and efficient but as @napilopez has shown here and several decades of loudspeaker engineering, theory, books and designs have tought us, it is not a prerequisite. Of course it is a good investment for a big loudspeaker manufacturer but especially for smaller ones the $100k investment must be financed and in many cases could be possibly better invested in other directions.
I don't understand why a experienced loudspeaker designer would really need a Klippel NFS to suddenly make well measuring loudspeakers. The NFS just makes measurements more fast and efficient but as @napilopez has shown here and several decades of loudspeaker engineering, theory, books and designs have tought us, it is not a prerequisite. Of course it is a good investment for a big loudspeaker manufacturer but especially for smaller ones the $100k investment must be financed and in many cases could be possibly better invested in other directions.
I wonder what the maximum SPL without compression the Sierra Towers with the larger 70-20xr ribbon tweeter could do when properly crossed over to subs? It's ~90dB sensitivity and the larger RAAL supposedly has much higher power handling than the 64-10 in the bookshelves.Granted, there is a reason to pay more for Revel flagships — they achieve spacious wide sound while also being capable of extremely powerful SPL without distortion, while Ascend cannot be played too loud.