Thursday, 9 August 2018

The Hadron

Bass reflex is an insufficient label to describe a speaker in a box with a hole in it. A wide variety of destinations await the traveler who buys a ticket with this country's name. Various alignments are available for a given driver with varying combinations of frequency response, step response, group delay and resonance. Some are named - Bessel, Bullock, Thiele/Small: B4, QB3, C4, etc... - many are not named

Rectangular boxes are easy to calculate and build and generally suck. Complex shaped cabinets are expensive and difficult to model and build but have the opportunity to transcend the compromises of flat surfaces and resonant construction. To design, build and measure complex cabinets, set fire to the failures and start over again to get better results takes persistence. Computer modelling reduces error but does not eliminate it. The difference between theory and practice is that in theory there is no difference while in practice there most certainly is.

Hadron Production Testing

A loud speaker is an ecocline of electronic, mechanical and acoustic interaction and thus resistant to accurate modelling - especially with complex cabinets across a broad frequency band. The way in which the rear wave propagates, reflects, and interacts with itself is but one of the facets of complexity. Each individual driver is different from the other, changes over time - even 
during each period of play - voice coils heat, suspensions soften, air density changes, etc... The variables are difficult to measure or estimate.

The cabinet is one of the most influential components in the performance of a loudspeaker while it is also the most costly, difficult and, often, least rewarding to experiment with.

Improved interior sculpting.

Many speakers are designed and built with modeling and built into rectangular boxes while the unquantifiable variables which can only be found with empirical data (verifiable observation or experience rather than theory or logic) are ignored because of cost and unknown results.

Frequency response is but one of variety of measurements which can describe a loudspeaker's performance but is often the only one communicated to indicate it. Step response, group delay, spectral decay, impedance also may indicate what the thing will sound like and still it is the listening which determines a loudspeakers success or failure - not the measuring. 
Nothing in the audio chain is closer to our ears than the loudspeaker while being one of the most complex. Acoustic, electric and mechanical measuring instruments assist us before bowing to the ultimate measuring instrument - the human ear.

Bass reflex alignments, like many other aspects of audio have been compressed into to poor examples by commercial and consumer interests. Smaller cabinets, 
easier to sell, are often chosen which have decent frequency response but often suffer poor transient response and thus have given bass reflex the reputation of “boom box”, "one note bass", "Monkey Coffin", etc... This has created a poor opinion much the same as horn loudspeakers when systems designed for stadiums were put inside living rooms - both less than optimal examples of the genre. 

The goal of the Hadron was to implement a bass reflex using alignments with proper transient response as well as low mass, low
 Q drivers (low loss) with fine quality paper cones, textile surrounds and field coil motors. These are much like the drivers used when Ultraflex and Onken bass reflex cabinets came into the world and are, in essence, drivers like they used to be made. They could be called: "new vintage drivers" to coin an oxymoron. While it is true that they do not have museum, collectors item or discovered buried treasure atmosphere they still perform as well in the real world and maybe after 50 to 100 years they will anneal themselves into the mystical.

Hadron Test Cabinets

Hadron development was heavily subsidised before being given to the business. The Hadron and its preceding iterations have been in development for over a decade and followed me around the world in my other career. Cabinets have been made in Dallas, Kuwait, Abu Dhabi, Modena and Bordeaux as it went along. Now, in the Mille Vache, amongst the cows, lavender and bumble bees the Hadron has come of age.

In previous posts there is some documentation of previous versions which shows the design and proportion. Differences now are:

1) Proprietary Driver - built with our specifications including field coil motors.

2) Horn designed especially for this application and driver providing physical time alignment in situ utilising Jean-Michel Le Cléac'h’s legacy of horn expansion.

3) Crossover network voiced with Thomas Mayer amplifiers to ensure optimum synergy when combined with these preferred devices. 

Thomas Mayer Amplification

4) Anechoic and resonant resistant, multilayer wood cabinet with resin impregnation.

 5) 100db efficiency for real First Watt operation.

The cabinets in these pictures are test cabinets. The Hadron is now in production with the same high calibre finished cabinets and styling as the Mojo (below) . Please email for inquiries, quotations and reservations.

Model One Mojo

Sunday, 1 July 2018

Going Solo - a new approach.

Going Solo

The next speaker we are introducing is the Solo:

Built around on the following driver.

Natural paper cone
Cloth surround
Solid phase plug
Copper shorting ring
Front vented and cooled (allowing 20Khz response)
70hz to 20Khz at +/- 2.5db 
68db @ -3db
Three inches in size

The spectral decay:

That is about as clean as it gets for any type driver and the sonics reveal it - easily stepping past the usual suspects for full or broad range drivers and among the best of any. The vocal range is very clean and natural. The highs are extended to 20,000hz, smooth with no harshness, ringing or break up. 70hz - 20khz with +/- 2.5db.

Here is the 3D model for the first cabinet design with this driver.

The Solo is ideal for smaller listening area environments. The quality paper yields a natural sound and the low mass/small cone provide clarity, smoothness, and speed due to the lack of overhang and break up.

With next to nothing for surface reflections there is no perception of the sound coming from the speaker itself. Imaging is exceptional.

They can be placed close to front wall without issues.

High Q also allows them to be used in open baffle applications.

An array of four of these drivers with a tweeter can reach an efficiency of 94db with a floor footprint of 11cm x 33cm. This will be the next cabinet featured.

This driver is also destined for a horn loaded applications of course ...

Here is what it looks like to the amplifier in the small 

We are now offering the Solo Loudspeaker for sale.

Please email for pricing and lead times.

Friday, 15 June 2018

Horns in small detail and how we put them in our speakers.

After being out and about recently in the wide world of audio many conversations were encountered about horns. Since I like horns and to talk about them, certain terms are used which should be conventional. The first of which what kind of horn has what name and how they compare to each other. Here is a well recognised comparison.

A common term which is missing from this chart is the "Spherical" horn profile.
Some say it is the Kugellwellen, others the Tractrix. It is actually closer to the Exponential lying closer to it than the Le Cleac'h. This, I have seen, is commonly misunderstood.

Here is a horn created with JMLC's expansion for a particular driver optimising for its exit angle and frequency range including the coefficient T expansion.

The roll back has been argued by armchair theorists as superfluous since the crossover point is ususally higher than the mouth cut-off frequency however in practice this has not been my experience. The roll back reduces mouth reflection and I believe is in part responsible for it being one of the most natural and best sounding of horns.

Not only that but it looks nice as well.

Some other things we do a little different are rear wave treatments.

Instead of attempting to eliminate rear wave energy with dampening our goal is to distribute it. This means not only diffracting gross reflections into small ones but also using shape to proportion them harmonically.

Pressurised construction allows the structure to be rigid and resonant resistant.

The cabinet is impregnated with resin as well as reinforced.

Front panel preparation.

Final Inspection and bottom plate assembly.

Here is the horn installed complete with its rollback.

Binding posts.

Completed Speakers.

This is the Mojo.
 Model One and Model Three.

We are now taking orders.
Please email for pricing and lead times.

Friday, 1 June 2018

Speaker Design in 3D

Here is a little bit on loudspeaker design using modern tools.

Many will recognise Autocad drawings from the days of old...

It is an excellent tool.

3D however adds another dimension - literally.

It has quickly become a native part of design as it allows visualisation and detail which 2D simply cannot compete with.

Not only can the objects be viewed from all sides but X-Ray views...

and scaled investigations allow an intimate understanding which is as unique... 

as it is powerful.

A new design for instance can be seen from all sides...

and angles not only to examine its expansion...

but also how it will be mounted, its clearances, 

and its overall appearance.

All before the first prototype is built.

This however does not come free. Learning these tools takes time as does the creation of the objects.

Sometimes it looks a little like architecture...

Here from concept to model.

Here is a preview of a new speaker.

A speaker cabinet is more than box, it part of an acoustic system.

It is as critical and complicated as any other component however this is often overlooked. The hierarchy of 1) design, 2) layout and 3) component quality is just as valid here as it is in electronics - in my humble opinion.

The box or "monkey coffin" has been over used due to its simplicity in design and construction.

Computer aided design and manufacture allow more elegant and effective solutions to the heavily braced and overly damped box. 

There is no substitute for wood and other natural materials and no magic bullets. It takes work to chord the modern with the ancient in pursuit of harmony to find solutions that excel.

We accept commissions for 3D design work - for both 3D modelling and 3D printing. If you have a project that you would like us to help you with please contact us.