Search results

Yes, that's correct. As mentioned power compression is eliminated so cannot be used to provide any kind of natural thermal limiting. However, we do this in the DSP. A simple thermal model of the driver is enough. There are some nice benefits compared to relying on power compression. First that...

Yes, that's right. We, and many others in the industry, have products that have a DSP model of the driver+cabinet and then calculate feed-forward correction to reduce the distortion in the radiated sound. The approach works quite well but there are some aspects of the driver behaviour that are...

It depends on the driver. The distortion reduction comes from two parts. First from the current output amp. If you have a very simple motor without any special features for controlling inductance distortion then this alone could be a decent 15dB reduction (see below) and in relatively audible...

No models involved. With a current output amplifier (high output impedance) the Qts becomes equal to Qes because the motional emf has no effect on the current. If negative velocity feedback is added around the outside of this the effect is the same as adding damping back into the system, so it...

The video title wasn't chosen by us. The trouble is that speaker engineering is an 80 year mature topic. Nothing is totally new and we're not trying diminish the achievements of anyone whose already implemented servo control. The main thing is the new sensor approach allowing us to apply it in...

Maybe do hold your breath for veco in 2-way. Volume displacement is limited, so we can't use it to extend the bass, but there are still benefits. Not least that we can use a current output amplifier which avoids power compression in the midrange and gains a small amount of inductance related...

Hi Everyone, I can understand that these pictures look dramatic and alarming to anyone that is a KEF loudspeaker owner, or that might potentially be considering purchasing KEF loudspeakers. I asked our operations team to collect some statistics for worldwide Uni-Q failures on some of our most...

Hi @ssashton , the details of this aspect of the design are explained in the white paper. It's downloadable from the specification table on the product page: https://uk.kef.com/products/ci250rrm-thx

@Zvu , thanks for the shout out, but I should clarity that my work on the Axi2050 was a very small part of the total project. Mark Dodd at Celestion was the driving force behind it, and deserves all the credit, along with the rest of the incredible team there. My bit was on the theory of how a...

Hi @Mnyb, you originally tagged me for a reply, but when I came to answer I saw that @AOR beat me to it. @AOR is one of our very talented KEF engineering team and nobody knows the way LS60 perform better because AOR did the DSP tuning .

Thanks for the suggestion. I agree it's something we can improve. Our spec sheet max SPL figure is based on 1m 1speaker instantaneous max peak SPL on pink noise. I think that what you suggest is better. A couple of extra notes. On active speakers we do as much limiting as possible with average...

What you see here is thermal protection kicking in on the tweeter. This occurs because a test sweep has extremely high average spectrum at high frequencies. On real music this isn't the case and this protection will almost never be triggered.

Hi @MAB, I really admire the thoroughness of your study. My experience is a bit different. Only today we have a driver in development where we are discussing Fs shift after production. Using this prototype as an example, the Fs directly after assembly was 57Hz and after sweeping in free air at...

Shameless plug for this thread which answers some of the questions you pose https://www.audiosciencereview.com/forum/index.php?threads/how-does-a-loudspeaker-cone-generate-acoustical-pressure.48261/

It's unfortunate that I can't post the Klippel paper. Anyhow, in the slides you can clearly see the "break-in" period marked on the graphs and distinct from the fatigue behaviour. In the paper Klippel defines this non-reversible change as "Initial exposure to mechanical load opens some bonded...

Hi Guys, Driver suspension break-in is a well known effect. For example, please see this paper from Klippel on the topic. https://www.aes.org/e-lib/browse.cfm?elib=16000 You can also find some slides from the paper here...

I'm involved with two papers on the program. @amirm, one is in the same session as yours and I look forward to meeting you in person. https://aesny23.sched.com/event/1SsKE/paper-presentation-iterative-metric-based-waveguide-optimisation...

Most trained acousticians would have studied radiation from compact sources into free-space at some point, but it's often done in a fairly abstract way using complex numbers. Mostly you find that velocity sources are used during teaching and there's not much discussion of flatness of transfer...

To try and explain the difference between case 2 and case 3 more clearly I've added some additional animations at the end of the first post.

The tube is either infinite, or it's extremely long. Because of this, the change in the volume caused by the piston displacing forwards is insignificant. The final volume of the tube is approximately the same as the initial volume of the tube. No air particles have been added or removed from the...