A beautiful design in both Form and Fuction
I asked Henry the genious behind many of the UK’s most impressive installs at Harwood Acoustics to design for me a set of full range enclosures for the Jordan Watts Modules I recently found inside These Cabinets
Henry was a little concerned about the height of these towering at 193cm but after a chat on the phone i reassured him i was more than happy!
We spoke about several aspects and features about the design, Henry explained how he designed this to be highly efficient down to 40hz, that it needed around 15-20watts of power and expects to see a maximum of around 4mm excursion if not a generally a static cone. Super efficient and a transient superpower!
If the driver can product high SPL with very little cone movement the result is short ramp attack transients. Kick’s and snares articulate effortlessly. If the cone doesnt have to travel far it doesnt take long to come to rest either.
Remember that the transient, body and tail of a snare can be milliseconds short, that means a speaker cone that is able to come to rest before producing the next input signal can work efficiently with less distortiion and pulls the loudspeaker out of the mud.
Expert advice for seasoned builder or novice starter
Not only did he provide a detailed explanation of how the Horn would couple with the driver efficiently, Henry discussed and detailed out every question i asked and i know he has the finess to explain this to a newbie or a life long audiophile, Complex or simple Harwood Acoustics covers it all!
He also walked me through the fabrication process and guided me on where to start marking out and building from, The details in the drawings might confuse those starting out but as i said Henry takes care in his designes not only to pay attention to performance but as a fabricator himself he clearly has building the design in mind from the start.
3D Modelling and Why its an Essential Tool
I modelled the enclosures directly off Henry’s drawings, He was kind enough to email me a high quality scan so i could copy it 1:1 straight into Sketchup, As he pointed out Facebooks algorithms on image compression made it hard to read so he went to the trouble of making sure i had the highest resolution to work from.
I honestly belive in modelling things before fabricating, i like to know where im going with a design and have the flexibility to make small changes without having to recalculate everything again and again, For example i am currently working on a redesign of these enclosures so that they can stand flat against a wall.
This means i can cascade process my design method down and ptogressibly work to a final itiration, Something thats been engineered as opposed to built, Tested, Rebuilt, Tested again, it works but i dont like working this way.
The only time i believe you should be taking on this methodology is once youve built enclosures your super happy with, Then you can go and make small changes like maybe swapping the dampening material for something else, Playing with room positions and angles, Even moving some furniture around can have a great impact on room modes.
These are things you can play around with for ever-after but the fact is you need a solid foundation to work from to understand the problems in the room.
The only way to learn that solid foundation is by modelling, Building and testing to the point you can trust your models to be acurate real world simulations, Knowing this gives you confidence to worry about external issues in the certainty they are not design inherent problems.
The Harwood Acoustics dampening of choice!
Henry asked me to order a specific foam mattress topper that he told me he has modled with repeatedly in Horn Response and built several designs with acurate results. This type of enclosure relies heavily on a harmonically balanced horn.
The dampening material acts as an energy absorber, Just imagine the rear wave of the speaker hitting a flat surface and bouncing back as opposed to its getting sucked up like a sponge.
Theres alot of professional acoustical foam in varying densities and materials to target fequency bands and dampen internal resonances, By converting acoustic energy into heat they can dampen frequencies inside the chamber. They also serve another purpose, Because the material will take up internal volume it will also alter the sonic character of the box by changing its Q or “resonanace”.
Positioning of dampening material is critical and can alter the response dramaticaly. Henry at Harwood Acoustics also provided a detailed schematic of how the material is to be applied to the enclosure.
Some things to consider here when desinging your own enclosure are boundary layer issues, Acoustical throttling (say the material covered the entire begining of the throat and was too dense it may choke the enclosure quite easily), Density and frequency absorbtion.
Improving cutting Efficiency and Designing a Cutsheet
Using Sketchup to layout a cutsheet makes life really easy when it comes to eventually having to cut all the pieces for assembley.
As you can see above by just turning your model on its side and using the Dimension tool in Sketchup you can easily mark out all the measurements, Luckily Henry is a Sniper fabricator and has made things easy with a 15.5cm internal width across the entire enclosure, This makes building the enclosure simple and stright forward.
We decided on doubling up 18mm MDF as the skeletal basis for the Horn section, Sandwiching the whole thing in another 36mm of Hardwood Ply
Piano black finish could be a nice option, I may also look at what veneers i can get my hands on in this size.
I wanted weighty towers for sure but at just shy of 23cm wide the towers stand tall and thin! With 4kg drivers sitting ear level the centered weight distribution becomes questionable!
Henry said it would be wise to make plinths, i may do this to start with and eventualy it might end up an entire TV media center cabinet.
With these tied together on each side like a pair of monoliths each side of my 65″ Samsung Q80 powered by a Hitachi Inverted Darlington Amplifier with 30 old school watts on tap these are going to sound SUPREEEME!!!!
Keep an eye out for the build!
