Bowers & Wilkins 800 D4 Diamond Series Review

Audio Advice became a Bowers & Wilkins dealer in 1980, just after the very first 801 speakers was introduced in 1979. We have witnessed all of the changes to this incredible line of speakers over several decades. Today, we're excited to announce the new Bowers & Wilkins 800 D4 Diamond Series flagship speaker models.

You may not own Bowers & Wilkins speakers, but you have probably listened to music or watched a movie produced on them. You’ll find them from Abbey Road Studios to Skywalker Sound and many more. The super-critical recording engineers at these facilities chose them for one big reason — they are incredibly accurate in reproducing the sound being fed into them. This is a lot harder than it sounds as many speakers either color the sound or miss parts of it entirely.

When you have a speaker so widely accepted at the world's finest recording studios and video production facilities, it seems to really fire up your engineers to develop ways to further advance the state of the art. Bowers & Wilkins has an amazing engineering facility in Southwater, UK where they have pioneered several techniques for measuring their speakers. They were the first company we know of to use laser analysis to find a better way to build speaker cabinets.

While their list of innovations would take up an entire article, one very important one was the introduction of the Diamond tweeter in the new D series of 800 models introduced in 2005.

Now, Bowers & Wilkins is introducing their new 800 Series Diamond models. They represent over 6 years of research with hundreds of improvements to what was an already incredible line of speakers. These are the 4th version of the Diamond models and actually the 8th series of 800 speakers, which surely says a lot about this brand's staying power. Think about that, 800 speakers have been used in some of the world’s best recording and video production studios for over 40 years!

The D2 and D3 versions introduced many new driver technologies that were quite innovative. One that stands out visually is the all-aluminum turbine head that houses the innovative Continuum cone This head totally isolates the midrange speaker and its distinctive shape greatly reduces cabinet diffraction which in turn improves imaging. The Continuum cone came out in the D3 series. This was a totally new approach based on years of R&D to virtually eliminate the midrange surround where their engineers found distortion was added. The purity of the midrange with this type of cone is something to hear. They even decouple it through a unique rod that attaches to the rear of the head. Finally, the Aerofoil woofer is made from a composite of carbon fiber and a syntactic foam core that varies in thickness to give them great stiffness with low mass for fast and accurate bass response. 

Our take on the new D4 line is Bowers & Wilkins has focused most of the technology in the new D4 on reducing even further any negative effects the speaker cabinet could have on the sound. But there is one exception, their new Biomimetic Suspension technology is one of the biggest speaker breakthroughs we have ever seen. It is one of those things you see and think, why didn’t anyone think of this before?!

The 800 Series Diamond models consist of four floor-standing speakers, the 801 D4, 802 D4, 803 D4, and 804 D4, one bookshelf, the 805 D4, and two center channels, the HTM81 D4, and HTM82 D4.

Now let's look at the new tech.

Bowers & Wilkins curved cabinet press

Reverse Wrap Cabinet

This used to be only on the top-end models but now includes all of the stereo pairs. This is a really cool process where multiple sheets of wood material are bonded together, then bent to form a one-piece shell that curves towards the rear of the speaker. The curved cabinet greatly reduces internal resonance while the layers give it great rigidity. It takes machines that cost over $1m each to produce these incredible cabinets. New for D4 on all the models is an improved way to glue the layers together. Previously, the glue between all the layers was applied with a machine to spread it out evenly. The new series has individual sheets of glue that go between every layer assuring Bowers & Wilkins of a perfectly consistent bond between them. The reverse wrap cabinet is held together with a spine of solid aluminum.

Improved Matrix Design of the 800 D4 Diamond Series

The Matrix design of having internal pieces to brace the cabinet has been used by Bowers & Wilkins for decades. New for D4 is the addition of aluminum pieces to the matrix. They found when they analyzed the cabinets, certain lower frequencies caused the cabinet front to flex slightly, which introduced a small coloration to the sound. The new and much beefier internal aluminum matrix measures zero cabinet flex across the audio range. The floor-standing models also added extra aluminum bracing where the speaker attaches to the plinth.

Bowers & Wilkins D4 matrix design

Top Plate with Leather by Connolly

There is now an aluminum piece that goes on the top of all stereo models. You can only see the outer perimeter when looking at the speaker, but it covers the entire top and is concave shaped where the tweeter or Turbine Head sits. This makes the whole cabinet more solid while reducing any resonances that might make it to the tweeter or Turbine Head and also lets Bowers & Wilkins insert some beautiful leather by Connolly to add a great design feature to them.

New Elongated Solid Body Tweeter Housing

We have seen this tweeter design for years and for the D4 series it is improved even further. They made it even more elongated than before and decoupled the mount to keep any cabinet resonance from getting into the tweeter housing. As always —and we find this tech just so cool —the entire housing is one solid piece of aluminum. This new mount and taper should really increase the open and effortless sound we already loved on the D3.

Bowers & Wilkins D4 Tweeter detail

Improved Damping in Turbine Head

The 801D4, 802D4, and 803D4 all have an aluminum turbine head. This in itself is just a great design but is not new for this year. What is new is a much-improved damping system inside the head itself. The head is not solid but has a star-shaped internal bracing system. For D4, Bowers & Wilkins improved the damping on the brace, making the turbine head even more inert.

800 D4 Diamond Series External Crossovers

Previously this was only on the bigger models but is now present on all the stereo pairs. A large aluminum heat sink-looking piece is mounted to the back of the Reverse Wrap Cabinet. This houses the crossover and serves three purposes. It reduces the chance of air pressure disturbing the sensitive electronic parts on the crossover, gives the engineers some more internal cabinet space for the woofers, and acts as a heat sink for the crossover components.

Improved Plinth

The aluminum plinth is now on all of the floor-standing models and is slightly bigger for better support. It is also better coupled to the metal parts of the Matrix pieces inside the cabinet for improved rigidity. The plinth is upgraded through the use of constrained layer damping with a steel sheet and damping material to make it even more solid and inert. We have always liked the way Bowers & Wilkins did the spikes on the 803 and up, which continues this year. You can easily roll them into place, then raise up the wheels to reveal the spikes once you get them in the perfect position without having to move them at all.

Anti Resonance Plug

For the floor-standing models, the Aerofoil woofer gets upgraded with a new Anti Resonance Plug. This helps keep the driver from flexing as frequencies drop and should offer up more accurate bass with less distortion.

Biomimetic Suspension

Now we get to the part that we feel is very special —the Biomimetic Suspension system. Every midrange driver we know of uses something called a spider, which is a critical part of the driver. The speaker voice coil is fixed to the inside of the spider and the outer perimeter is attached to the basket. The job of the spider is to keep the voice coil centered in the magnetic gap at the bottom of the basket.

Since the dawn of speaker drivers, the spider has been made from a solid yet flexible material with ridges in it. They are usually made from fabric.

When the Bowers & Wilkins engineers were searching for perfection, they did some measurements and found that the speaker spider acts a little bit like a speaker driver itself as it moves back and forth with the cone on top of it. The air movements it creates slams into the back of the cone and adds a small level of distortion. Some sounds even pass through if the main driver is porous like most are.

The interesting thing is, they discovered this in 2007! Yes, 14 years ago. They have been working on a way to improve this and it took them almost 15 years to come up with a design that had all of the benefits of a typical spider, but was completely open to prevent it from making a sound of its own. This is their new Biomimetic Suspension, and to us, this is just such a breakthrough! You can see from the image how this is just such a great idea.

Biomimetic suspension spider detail image

800 D4 Diamond Series New Luxurious Finishes

The D4 models give us the best variety we have seen in cabinet finishes. They are gloss black with black grills and black leather, satin rose nut with black grills and black leather, white with gray grills and gray leather, and satin walnut with gray grills and gray leather. We have to say the satin walnut finish is our favorite, but with this kind of variety, there should be a finish that will be perfect for any type of decor.

Bowers & Wilkins 803 D4 finishes in Rosenut, Walnut, Black and White

The Bowers & Wilkins 800 Diamond Series Models

Bowers & Wilkins 800 Diamond Series Tower Speakers

For 2021 and the D4 line, we have four floor-standing models and we love the fact they have brought back the iconic 801 designations for the top-of-the-line model. All but the 804 D4 Floorstanding 3 Way Loudspeaker use the Turbine Head and all use the exact same Diamond tweeter with the new elongated housing.

The 804 D4 has a 5” Continuum cone FST midrange driver with the great new Biomimetic suspension coupled with 2 6.5” Aerofoil bass drivers. When you move up to the 803 D4 Floorstanding 3 Way Loudspeaker, you get the Turbine head for much more open and less colored midrange with the same size driver coupled with 2 7” Aerofoil bass units. One more step up to the 802 D4 Floorstanding 3 Way Loudspeaker, and you get a 6” Continuum cone FST midrange drive mated up with 2 8” Aerofoil bass units. And at the very top is the 801 D4 Floorstanding 3 Way Loudspeaker with its dual 10” Aerofoil woofers.

What you will hear as you move up is much better midrange and deeper bass going from the 804D 4 to the 803 D4, but make no mistake, the new 804 D4 is spectacular and has an appearance that might be more suitable for traditional environments. Moving up to the 802 D4 and 801 D4 gives you more dynamic impact, an even more open midrange, and obviously much more bass impact as you move up.

The 801 D4, 802 D4, and 803 D4 all have a sensitivity rating of 90 dB and the 804 D4 is 89 dB. This makes them all fairly easy to drive, but you will certainly benefit from a great amplifier. We loved the way our test samples sounded with McIntosh MC611 mono block amps!

Bowers & Wilkins 800 Diamond Series Bookshelf Speaker

The 805 D4 Bookshelf 2 Way Bookshelf Loudspeaker is the one stand-mounted speaker in the lineup and has a 6.5” Continuum cone combination midrange bass driver which does not get the Biomimetic suspension due to the extra movement since it serves the lower frequencies. These will make a great speaker for small rooms, but our heart tells us if you are already close to $10,000 for a pair of these with the stands, anyone thinking of that can probably afford the 804 D4, which offers a whole lot more for the 25% difference in price and the footprint of floor space is roughly the same.

Bowers & Wilkins 800 Diamond Series Center Channel Speakers

The new HTM81 D4 & HTM82 D4 Center Channel 3 Way Loudspeakers are nicely done as well. These both use the Biomimetic suspension for the midrange drivers, and to get as close as possible to the advantage of a Turbine Head, have a separated aluminum enclosure inside the cabinet that houses the 5” or 6” Continuum cone FST midrange driver. The HTM82 D4 has dual 6.5” Aerofoil bass units with the larger HTM81 DR getting dual 8” bass drivers. Our advice here is to match up the HTM81 DR with the 801 D4 or 802 D4 and the smaller HTM82 D4 with the other models as the midrange drivers are the same size.

Overall Recommendation

Audio Advice was lucky enough to receive a pair of 803 D4’s before the official launch date and set them up on our big McIntosh stack in the Raleigh showroom. Before we started our listening sessions, we expected there would be some improvements in bass definition due to the new Anti Resonant plug, new aluminum cabinet bracing, and the improved plinth. We also suspected we would hear an even more open and airy extended top end. As we listened, both of these areas have clearly improved. However, the shocker was the midrange. We thought the new Biomimetic Suspension would make some difference in midrange openness, but this felt as big to us as when the Continuum midrange driver was first introduced. As good as you thought the midrange was before, and it was darn good with the Turbine Head and Continuum driver, it is far better now. Voices just sound so realistic and you would swear the tenor sax is right in the room with you! We are sure part of the improvements are due to the improved damping and mount to the plinth as well.

When you first look at the new models, you might think, these do not look that different from the D3 Diamond series and they have just made some minor tweaks to come up with a new model. Nothing could be further from the truth. According to Bowers & Wilkins, there are hundreds of improvements, and we can not see 90% of them. When you hear these, you will know the engineers at Southwater were very busy for the last 6 years coming up with all of these changes. Each one may seem like a small change, but when you add them all up, you get a vastly improved new line that not only pushes state-of-the-art sound closer to the real thing but also just looks fantastic.

Bowers & Wilkins 801 D4 side profile

We hope this overview of the new 800 Series Diamond models from Bowers & Wilkins has been helpful to give you a glimpse into how great these sound. Both our Raleigh and Charlotte locations will have demos on display for your listening pleasure. We invite you to come to check them out. If you have any questions about these or anything related to audio or home theater, please be sure and contact us via chat or email, give us a call, or drop by one of our stores.