Multiple Chamber Aligned
in Parallel Cavity Resonator (MCAP-CR)
Suggested Cabinet Designs
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Important Notes
Some
reference design and drawings are listed here.
All the drawings below are based on author's calculation and design
experience but not tested by author unless noted diferently.
Some of these are designed per request by certain readers. Most of
designed cabinets are for more general use than for specific drivers.
Suggested drivers are listed as well.
You
may use this design or change design by yourself, if you agree to the
condition that all the risk is taken care by youreslf. So you must not
complain about design or drawing errors or sound if you do not like the
sound of your works using these designs. This applies to all the
coontents of my pages. User's satisfaction is not guaranteed.
Availability of standard wood material depends on business area.
-
It is assumed that standard thickness of plywood is 12mm, 15mm, 18mm,
21mm.
-
It is assumed that standard thickness of bonded pine wood is
12mm, 14mm, 18mm, 24mm.
Your information of available wood materials in your area is very much
appreciated.
I wish you good luck with this information.
Index
Note:
TR120b1 (design
not yet complete)
TR120b2 (drawings checked by author: 2009/04/25)
Outline
- 6 degree of freedom cavity resonator with 4.5" - 5" drivers.
- b1 is for 15mm thickness woods and b2 is for 18mm thickness
wood.
- Chamber sizes are a little smaller than TR130b
cabinet, but larger than TR130a
cabinet. Suggested drivers are F120A, FF125K, and FE126E by
Fostex, W5-1611SA by Tangband, L5 by Omnes Audio, HX132 by
Ciare,
and other 4.5" to 5" drivers.
- Some 4" drivers with Neodymium magnets by Tangband may be
used, but may not fit..
- You may try 6" - 6.5" drivers as well, if you understand
the risk and are self-sufficient.
Designed Characteristic
Frequencies
30Hz, 40Hz, 53Hz, 66Hz,
74Hz, 99Hz
External Dimension
b1: 900H x 230W x 230D per
channel
b2: 900H x 236W x 244D per channel
Assembly Drawings
TR225a1 (design
not yet complete)
TR225a2 (design was checked by author: 2009/05/06)
Outline
- 6 degree of freedom cavity resonator with 8" - 9" drivers.
- TR225a2 is all front duct version. It is designed to set along rear wall.
- This
cabinet may be huge for ones who lives in small apartment like myself.
Cabinet will be heavy and may not be assembled or handled by single
person. I cannot manufacture this cabinet, but may be useful for some
special drivers like limited models by Fostex, Feastrex or other high
performance drivers. Cost of one pair of cabinets will be 2,000 USD, if
all the labour is supplied by youreself. Letting professional
carpenters all the manufacturing will cost 5,000 - 10,000 USD depending
on pricing.
- I would rather recommend 5" systems like TR130b or c than
9" system, if you do not require specially high performance.
Designed Characteristic
Frequencies
External Dimension
1200H x 400W x 400D (192L
or 6.83 cft per channel without double side panels)
TR130c3(design
checked by author: 2009/05/09)
Outline
This
is modified version of TR130c1. TR130c1 has complex structure and even
myself made mistake in one channel (it was modified as version c2).
Version c3 was designed not to make assembly mistakes. Basic design is
same as TR130c1.
Suggested Drivers
Any Feastrex 5" drivers
especially D5e
FE138ES-R by Fostex
W5-1611SA by Tangband
Other powerful 5" drivers
6.5" fullrange drivers may be suitable
Assembly Drawings
DU130a (design checked by author: 2009/05/10)
Outline
This
design is for non-classical music. Lowest characteristic
frequency was designed to 42Hz. Other characteristic frequencies are
58Hz, 82Hz, and 104Hz.
Lowest
frequency of 42Hz will suffice for most music sources except particular
classical musics. This is easy to assemble and economical.
Suggested Drivers
Mild 5" drivers are suggested.
L5
by Omnes Audio or HX132 by Ciare may be good to use with DU130a.
TR130c3 is recommended for powerful drivers. Mild 4" drivers like
FE103E by Fostex may fit.
Assembly Drawings
Common Notes and Tips
Selection of Woods
My
design assumes that structure is rigid enough. It means that vibration
of cabinet is not taken account. From this respect, wood may be
selected in any way, unless material is not rigid enough.
I do not
recommend very soft and/or light materials for structural materials. I
prefer relatively heavy (density is bigger than 0.5 kg/L) materials.
Another
important thing is availability and price. There are reasonably priced
plywoods and bonded woods. MDF is also available, but it does not look
good. Practically best material is linden-apiton plywood. It is
relatively heavy and proce is reasonable. Another choice will be birch
plywood. Birch plywood is more expensive than linden-apiton, but
heavier.
Bonded pine wood looks better than plywoods. Disadvantage
of bonded pine is its softness and its dimensional change. Even though
pine wood was cut accurately, it changes dimension to 0.x %. This
change makes difficult to assemble.
One advantage of DIY is to save
money. We may choose best cost / performance materials with best
drivers to realize best cost / performance.
Absorption Materials
Absorption materials
should be chosen by users. Function of absorption materials is mainly
abosorb mid-range and higher range sound pressure inside the chamber.
Low-range sound pressure will not be much affected unless ducts are
plugged. Plugging any duct is not recommended, because MCAP-CR is
designed to maximize characteric vibrations of masses in ducts.
I suggest not to use too much absorption materials, because
it makes the sound dead. Using absorption materials must be based on
user's preference.
Suggested Usage of Absorption Materials:
- Use generally available and less expensive materials like
sponge, cotton, soft cloth, soft paper, etc.
- Begin with nothing then add one by one as you require.
- Hang soft sponge behind the driver in
the main chamber.
- Some absorption material layer (10mm - 20mm) may
be
laminated to walls in the main chamber, if you feel that reflected
sound from back cavity is annoying.
- Some absorption materials may be set in subchambers;
however, please note that you may not be able to remove absorption
materials from subchambers after assembling the cabinet.
Important Notes:
- Some absorption materials like glass wool may be harmful
and not recommended.
Speaker Wiring Terminals
Setting terminals should
be taken care by users.
Some terminals may release sound pressure from its gap or gap between terminal and cabinet. Recommended
terminals are:
- +/- independent terminals (expensive solution)
- Small flange type terminals (less expensive solution)
- Not to use terminals but drill holes to cabinet for wires from driver
and connect to speaker cable outside the cabinet or even directly to power amplifier. This is the least
expensive solution.
Large and thin plastic terminals are not recommended.
Choosing Wires
Expensive
wires are not recommended. Cables really affect sound quality, but
effect is very small compared with other reasons like driver selection
or cabinet design & manufacturing. 0.75 - 1.25 square milimeter
copper wire for power handling use may suffice.
You may try very expensive audio wires. It is up to you.