LOUDSPEAKERS 1, new from 2000.
Edited 2011.

In 2000, I made a few pairs of loudspeakers which were very well reviewed
by the main local hi-fi shop in Canberra at that time, Durarone Hi-Fi.

Unfortunately, Duratone's desire for 50% of the retail price placed my speakers
at the same price as European made imports which had been widely advertised in
the hi-fi press. The models sold at Duratone and other hi-fi stores are rarely the
high priced elaborate models which were used by imported brands to gain their
reputation favorable press reviews. So the hi-fi shops mainly sell low grade
speakers with a lauded brand name. The buying public is fooled into thinking they
are buying good speakers. In a shop, many buyers become entirely irrational.
The buying public do not like to buy anything that is not a well known brand
even though the hand made product can offer far better performance.

I have not made any new loudspeakers since 2001, due to lack of demand, and
fickle buying patterns of so called audiophiles.

But the speakers I did make are much treasured by their owners, and they deserve
a mention at this website which is primarily devoted to good quality hi-fi.

There were two models which I made and offered in 2000, Sublime and Supreme.

Both sets have two separate enclosures with smaller midrange-treble unit
placed on top of the larger bottom bass unit.

Sublime.
sublime271w360h.jpg

Supreme.
supreme271w344h.jpg

The enclosures have 38mm thick top and sides made from 3 layers of plywood.
There are two layers of 16mm and 17mm structural plywood with an outer
layer of 4.5 mm of veneered plywood for appearance.
The resulting asymmetrical panel density tends to reduce resonances.
There is a large amount of well placed internal braces to prevent movement of
the enclosure walls and to interrupt internal standing waves.

The front and rear baffles are real timber hardwood planks of Victorian Ash,
42mm thick on the front and 33mm on the rear. The front baffles are fixed
to the side and top/bottoms by many screws and internal hidden slotted
aluminium angles so that no fixing is visible from the outside, but the screw
fixing does allow the real timber to expand and contract. The front baffles
and rear panels have foam sealing gaskets to ensure air tight contact but to
also provide a soft join between the panels and the sides and top of the
enclosures, allowing the small amount of natural timber expansion and
contraction and to give added reduced acoustic coupling in the enclosure itself.

The enclosures have narrow front panels and well rounded corners to minimize
diffraction and optimize stereo imaging. The the sound from the rear of the
bass and mid-range cones is absorbed by high density polyester wool which
is used in acoustic sound proofing where a high level of attenuation is needed.

The bass units and mid/treble units have been built as separate enclosures to
prevent mid-range sound from vibrating the larger bass enclosure woodwork.
There is a layer of felt on the bottom of the mid/treble units, and because
of the weight of the units, ( 85kg for Sublime, ) they have plenty of inertia
to prevent box movement and there is no need for floor spikes or other point
contact supports to improve the sound.

I made the speakers at a time when I was willing and capable of fine woodwork
after a previous career of 30 years in the building construction industry where
I worked as a carpenter and joiner while supervising others around me.

To obtain excellent sound, enclosures should have thick walls, be well braced
and baffled internally, and thus be very heavy. The appearance due to the fine
timber grain finish is completely unnecessary to enhance the sound.
The enclosures will work excellently if made from any stable panel material of
40mm thickness, and may be screwed and well glued at corners. It is easy to
round off the external corners, fill all screw holes, sand down all surfaces, and
apply any paint one wishes to use.

The loudspeaker market is supported by very fickle buyers relying on reviews
and virtual slave labor to do the dirty work in assembly  line factories so that
huge profits are possible. Profits and fickleness do not improve sound quality.

So for those wanting to avoid costs and get good sound, a painted finish over
roughly made enclosures will work perfectly.

The bass units are 55 litre ported reflex with a box frequency below 35Hz and
hence all frequencies above 40Hz are delivered by the front of the bass cone
without the ill-effects of resonances which occur
in enclosures which are too
small so that the enclosure resonance Fb is too high. Such small enclosures
lead to better company profits and low manufacturing costs but the hi-fi
listener is robbed of good sounding bass ! The bass from my 55 Litre units
extends to 22Hz.
No sub-woofer is needed, and the bass sounds well integrated
and fast without the tendency of  sloppy bass and woolliness that sub-woofers
so often generate.


The mid-range and treble enclosure is a sealed box, and crossover F are at
300Hz and 3kHz.

All the speaker drivers are Seas units because I liked their accuracy, lack of
coloration, low distortions, smooth response within their bandwidth, lack of
cone break-up behavior, and their ease of use since relatively simple
crossover filters were required.

Bass drivers are SEAS L21RNX/P
Mid-range drivers are SEAS MP 14RCY/P
Treble drivers are SEAS 27TF.

Details of these drivers were at the SEAS website, but I am not sure if any of
these drivers are now available anywhere.

The crossover filters use neatly layer wound coils of high temperature rated
polyester-imide enameled copper winding wire, round section, and wound on
glued plywood bobbins and without any iron cores.
Capacitors were initially a combination of  well rated polypropylene
and non-polarized bipolar types.

In the last set of speakers I made I have used
polypropylene capacitors only, supplied by Obligato, as directed by a fussy
customer. These capacitors were much larger than those they replaced,
and gave a more detailed sound. 

Any type of amplifier can be used.

Sensitivity is 90 dB per watt at one metre for each channel.
Impedance :-
Sublime is 6 ohms nominal, with a minimum of 4.5 ohms at 300Hz.
Supreme is 9 ohms nominal, with a minimum of 6 ohms at 300Hz.
Frequency response is 22 Hz to 22 kHz.

I used Vandenhull silver plated cabling internally.
Connections for speaker cables were recessed gold plated 4 mm banana sockets.
Binding posts for screw down on wire have not been provided.

Any type of speaker cables with 4 mm banana plugs may be used between the
amplifier
and bass speaker which has double parallel sockets to allow a short cable
to connect to the mid-treble unit to the bass unit. The bass unit and mid+treble units
may also be bi-amped or bi-wired.

Recommended minimum amplification is 25 watts per channel.
Maximum power handling is 100 watts, which will produce an SPL = 109 dB.

Total weight for Sublime is 85 kilograms, Supreme is slightly more.

Overall Dimensions :-
Sublime = 310 mm wide by 1,070 mm high by 450 mm deep,
Supreme = 310 mm wide by 1,175 mm high by 450 mm deep.

sublime-crossover.gif

For DIY speaker ideas and detailed Sublime box details and for a single box
3 way full range speaker, go to
DIY speaker designs

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