Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Meridian Apodising filters in PerfectWave DAC?

"Apodizing" technology appears everywhere. I talked with Mikael Bladelius here in sweden who is the designer of the Bladelius products and he also has a Apodising filter in his Embla, but you can select between the different filters in the setup menu. Now he wasn't entirely happy with it compared to his old FIR based filters.

Harley`s review of the Meridian CD player
As much as I love our industry and the people in it, I have to say there are only a handful of people and manufacturers that I really admire and look up to. Robert Harley, from TAS, and Bob Stuart, from Meridian, are among those that I really admire and when the two interact, I am doubly interested. Robert Harley I`ve known for years, I don`t think I`ve ever met Bob Stuart, but I certainly have followed Meridian for years and they are my kind of company: technically advanced and game changing.

So, when our customers and beta testers keep asking me to explain just what makes the new PerfectWave DAC sound so good - especially on standard Red Book CD`s - I struggle to explain about the new breed of apodising filters at work. Certainly there are many aspects of the PWD that are standouts, but the type of digital filters in use, known as apodising filters, are truly game changing as is the performance of our DAC. So imagine my surprise when I open up the August issue of the Absolute Sound Magazine (TAS) and here`s an article by one of my favorite technical writers, Robert Harley, explaining how they work, what they do and why they change the game forever for Red Book CD reproduction. Then, following that is an even more interesting interview with Bob Stuart who offers some excellent insights into blind testing, perceptions and how people need time and space with their systems to make good evaluations. Really interesting reading.

Apodising filters solve one of the biggest problems in digital playback, known as pre-ringing. Pre-ringing is a very unnatural event and the ear is apparently quite sensitive to this phenomena. Its importance to what we hear on a digital recording was first brought to our attention through an AES paper written by Dr. Peter Craven in 2005 and the work he and Bob Stuart have done on identifying this problem, the effects it has on what we hear and a special type of filter that not only reduces the phenomena in the DAC, but the CD itself!

This is truly ground breaking work and we`re delighted that we were able to bring the PWD out with the latest generation of filter sets that take advantage of much of their work.

Robert is a far better writer than I, so if you are interested in learning more about how these filters work, what they do to the sound and the cool new Meridian 808.2 Signature Reference CD player, pick up a copy of the August issue of TAS and have at it.

For those of you receiving your new PWD`s soon, there are several versions of apodising filters available to play with through the touch screen. Have fun! What a great learning experience awaits you.