Delta
4 R5 – the USA project
§
1 – Introduction
I’m
since long time into DIY loudspeakers, and being an old time friend of Renato I
always followed closely the evolution of his projects and wanted to build some
of them.
However,
as real DIY addicted, I always made for myself speakers inspired by his work but
with so many ‘personal’ changes that cannot be classified as ‘GR
Research’ projects.
So,
when I was finally able to corrupt Dominik, my stepson, into loudspeakers
building and he decided to put some
time and money into it I was delighted to finally being able to build the Delta
4 in their latest release R5
The
project was scheduled to be completed in one week during August 2008 vacation,
having to deal with unusual logistic problems: I live mostly in Italy, he lives
in Ohio and we met at my wife in Atlanta, GA
This
on one side jeopardized the opportunity to have a ‘perfectly executed’ job,
but on the other is the proof that such an apparently complicated and really
sophisticated project can be successfully accomplished in short time, with few
basic tools and by 2 people who have some experience but are not professional
carpenters or electroacustic engineers.
The
lack of available time forced us to postpone at a later stage the construction
of the frames that give the Delta4 their elegant final look.
§
2 – The project : Preliminary
work
The
first step was to analyze the necessary components and materials, and check if
everything was available in the States.
This
was positively accomplished with a surprisingly small list of suppliers:
a)
– Components
Woofer
MAD1259 and Scan Speak 2010/8513 : Madisound.com
www.madisound.com/catalog/product_info.php?products_id=1402
B&G
Neo 8 and all x-over parts:
Partsexpress www.partsexpress.com
ScanSpeak
D3806 : was the most critical to find, because apparently ScanSpeak decided
to drop this component from their retail catalogue and (afaik) sell it only to
professional builders.
We
were lucky to find a Scan distributor eager to empty out his shelf and we got 2
pairs at bargain price, currently is still possible to find this component on
ebay or on some e-dealer online catalogue although at full price like:
We
recommend, however, to have a look at the US or Canada Scan distributor and call
for availability.
b)
– Wood and other Material
The
first (boring) step was to convert all the drawings from metric to US standard
measures.
This,
combined with the fact that we could not rely on a professional carpenter with
high-accurate numeric-controlled cutting systems, forced us to ‘simplify’
the measurements by slightly modifying the original dimension in order to have a
better fit with local units of measure.
Moving
to the real stuff, we decided to use ¾
inch MDF panels for the main box, ½
inch MDF for the mid/tw ‘head’ and solid wood for the ‘booms’ and their
supports.
After
checking on several wood companies, we found out that we could get all that we
needed from the local Lowes and Home Depot stores.
The
trick for the wood was to:
·
start from one of their standard ¾
MDF sheets
·
prepare a draft of the major straight-line cuts
·
Have this preliminary cuts made directly at Lowes/HD trough their
available big saw (they charge you little or nothing for that). This will allow
you to manage relatively small sheets of MDF, with the advantage that you can
load them on your car and that they are less vulnerable to deformations
·
Complete the cuts at home with your saw.
All
panel measurements, details and materials are in the attached
PDF file (7 pages), that also include on last page the draft for cutting
the big MDF sheets.
An
important warning: if you rely (like we did) on handmade cuts w/o precision
instruments and you are not a very skilled carpenter, the best way to manage the
‘sloped’ front&rear panels is to pre-cut the panels, then cut the lower
base triangular ‘slice’, test the panels on the base, mark the right cut to
properly fit the top edge and then cut it, instead of relying on measurements
that will probably leave you with some inaccurate cuts.
Concerning
the other materials for the cabinets, like bolts & screws, damping material,
glue, paint etc. there is no problem in buying them at the same Lowe/HD or any
home improvement store in your area.
c)
- Tools
Here
the list of the basic tools needed:
·
A flat and stable workbench.
·
Jigsaw, with tilting capability
·
Circular saw (with tilting capability)
·
Rig for the above
·
Router (best with fixed/plunge base)
·
Vacuum cleaner (best if connected to saw and router)
·
Soldering station
·
Usual small tools like screwdrivers, pliers etc.
d)
– Crossover
·
We decided to buy ‘reasonable top’ components, and we decided to get
our components from Part Express for 2
main reasons: they have all that we need in their catalogue and (last but not
least) Dominik happens to live close of their headquarters, and he cold drive
there and buy everything with 20% discount at one of their ‘special sales
days’
·
The detail list of the x-over components is in the attached file X-Over
Buy List.xls
§
3 – Assembling the Speakers
Start
with assembling the base ‘clog’ that will host the x-over plate and the
binding posts. This is not difficult, just remember to cut the hole for the
binding post before assembling the box, otherwise it will be more difficult.
Also,
better cut the 12x11” square in the 15x16” panel before building the clog.
Pictures 06, 07 and 08 shows how the ‘clog’ look like.
Parts are on page 2 of the drawing
Important
note: it is advisable at this stage to have the x-over boards ready, so you can
match them to the base and pre-drill the holes that will secure them in place.
Doing this task now is much better because it is much easier now than at later
stage when the box is assembled and there will be much less space and view. See
Pic07 for detail
Pic.7 - Detail of the x-over board, pls note the pre-drilled holes
Next, put together the prism, using the triangular pieces and the front and back panels, plus the reinforcement front panel. Parts are on page 2 and 3 of the drawing.
Of
course, you need to cut the circle for the woofer before assembling the pieces.
This
is the most critical part of the construction: without professional tools (or
craftsmanship skills that are forbidden for me…) you will need to trim and
refine the box when you will ‘introduce’ it to his matching clog.
Page 5 of the drawing shows the edge cut needed for the front and back panel.
When the triangular box is made, before installing it on the clog you should seal the top corner: get an old salad bowl, prepare a mix of glue and sawdust until it will look like plastiline and use it to seal the front&rear panles connection from the inside. You may want to let the ‘plastiline’ dry with the boxes upside-down, like in Pic 05
Pic.5
- The ‘bass triangles’ upside down to allow the sealing plastiline to dry
Next step is to assemble the triangular box on top of the clog: once the edges are properly trimmed to match this is a no issue job: the weight of the box itself will keep it in place; just don’t move the thing until the glue is properly dry. (see Pic 09)
Pic.9
- The two bass boxes ready to be glued on the clogs
Now,
while the bass boxes are drying, is time to prepare the mid-high towers, by
assembling front & rear panel and the ‘booms’ that will act both as side
walls and as structure.
All needed parts and quotes are on page 6 of the drawing, needless to say that all the cutting for the speakers must be done before glueing the front panel to the box.
Picture 08 show the half-completed mid-high towers, with the front panel almost done and just ‘tried’ on the box.
Pic.8
- Base and semi-assembled towers
When everything will be properly dry, it’s finally time to make the supporting shoulders for the MH towers and try to match all the components together (picture 11) : finally the beast starts to take shape!
Pic.11
- One speaker tested for final assembling
To
make the 4 supports properly fit is another task for professionally skilled
people: average DIY like me should consider to lose some time in a
‘trial-and-error’ process and obtain a perfect match with repeated small
corrections.
The
good thing is that the wood used is cheap and easy to work, so if you screw a
support you just cut a new one.
Once
you have painted the speakers (pic 12), before the final assembly is better to
lay the internal wiring: pre-cut the wires and fit them in the towers.
Pic.12
- Painting the bass boxes
There
is not a ‘right way’ to do it, every approach is ok as long as the
electrical connection is sound, the holes in the boxes are properly sealed and
you are happy with aesthetics.
We
decided to keep the wires straight and so we drilled 3 holes on top of the bass
section to allow the cables for the 3 speakers to reach the x-over board. The
holes were then sealed on both sides with silicon glue.
Remember
to allow enough length to enable the soldering to the x-over OUTSIDE the box (see
pic 13)
Pic.13
- Detail of x-over board ready to be connected to the speaker
That’s about it, on pic 14 you see the two speakers ready for final assembling: x-over installation and finally the speakers (pic 15).
Pic.14
- Mounting the Scan 3806
The
x-over board should be connected to the speakers and binding posts outside the
box, then placed on the bottom of the base trough the woofer hole and secured in
position by some screws (remember the note at the beginning of this chapter…)
A
few rubber spacers between the board and the base will grant that the x-over
components are not impacted by vibrations.
Last
critical operation before installing the speakers is to fit the dumping
material. The bass box must be completely filled, and the operation may be
tricky because it will look like that ‘all that stuff can’t possibly fit in
this box’
We
used insulation rolls of glasswool bought at HD (that rose big rolls you
normally lay under the roof), and here are some tips and hints on how to proceed:
1
– cut the right quantity/volume by measuring
length and height of your material. Volume must match the bass box volume
(30 litres)
2
– Now that you have the right quantity of material, slice it in smaller pieces
that will be easier to press and fit
3
– Insert the pieces in the box, starting from the hidden edges and press the
pieces in place.
4
– lay one ‘mattress’ cut to size on the x-over to protect the components
5
– continue filling the box until all the material is used
6
– remember to let the cables of the woofer free…
On
pic 16 the Delta 4R5 are ready for their first song, the ‘thing’ in the
middle is another DIY speaker of smaller cost and ambitions.
Pic.16 - You can’t see it but they are playing music, and the do it pretty damn well!
How
do they sound? In one word: gorgeous!
Have
Fun!
Pic.1 - Dominik tries to understand what to do with all this wood and metal junk
Pic.2 - Parade of all the cut pieces, credits to puppy Roxy’s push for the blur
Pic.3 - Assembling the x-over
Pic.4 - A crossover board completed. Pls note that all components are mounted on soft rubber tabs or thick bi-adhesive tape for vibrations, and that heavy components are secured by nylon stripes.
Pic.6 - Top and bottom of a bass box ready to be matched, the x-over board is also tested for proper fit in the base
.
Pic.7 - Detail of the x-over board, pls note the pre-drilled holes
Pic.10 - A special guest that we found in the garage
Pic.14
- The
two speakers ready for final assembly, much better to put them on a table so you
don’t have to bend on the floor for soldering the cables to x-over
Hall Of Fame