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I.S.C.T. HOW LOW CAN IT GO. The G-Force Tang Bang Sub Woofer Build.

Audiolab 6000CDT Dedicated CD Transport

UpperCut

Active Member
Joined
Feb 11, 2016
Messages
71
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33
Location
New Zealand
A mayor problem in all my DIY work is the waiting for parts & items from overseas due to delays in freighting, availability or simple only through the unavailability of things here in NZ as well as of course everything cost down here so much more or just getting it here to NZ can get difficult as freight cost a lot of money.

Anyway, the new G-Force sub woofer project was mainly build from MDF (Of Cuts), but the idea came to me after reading so much about this Tang Bang W8-740P 8 inch woofer and with that what people had done with it or tried doing & what different cabinet volumes had been used with it.

It is really all quiet strait forward as this was the first woofer of that type I had ordered from PE for testing in a couple of project enclosures with over 30 liter plus & this one with 21 liter, the enclosure is a little different as I wanted to try some new ideas & materials in it, and I only just received these materials after waiting for it for some month now. As for new ideas for example Im using a new type damping material I found way back, and that the inside of this cabinet (Inside only at this stage) will be covered with some skin like product etc.
The enclosure volume which is empty 21 liter will end up to my calculations in the end with about 13.5 to 14.0 liter so not a lot of volume, but when I look at the recommended enclosure volume of 7.1 liter (.25 cuFt) for a vented, and 3.1 liter (0.11 cuFt) for a sealed my volume idea is still double that.

Accompanying this woofer are two 10 inch Passive Radiators from PE as well, and that is it but I really want to see if this woofer will perform with such small volume as predicted as it works quiet well in a larger cabinet like my Renegade project were it is presently still mounted in - to Run In.

rgs UpperCut


Images are from the last couple of days .... Only today I was doing the first undercoat and first fitting of woofer.

The very first time weighing in with woofer & 1 PR only = just over 21 Kg ....




 

UpperCut

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Feb 11, 2016
Messages
71
Points
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Location
New Zealand
Hi there,

After days on end having cold & moist weather not been able to do any painting here is the last 'Melon Yellow' coat on the enclosure!

I also have started to build a set up for this enclosure a bit different to the norm (Nothing New) as I want to use that as a single item below the unit Solid Spikes pointing towards the enclosure - as well as it is needed for the Display Platform project LINK: - http://www.hifivision.com/diy/63416-i-s-c-t-rather-calling-speaker-display-platform-then-just.html -.

There is of course a special reason for trying this as in my projects which have spikes I make sure that I have no air leaks so I block the holes for these spikes with a rubber threaded nut which enables it to be virtually air tight. This will be handling an opposite dual nut to enable the close up as well as fitting to the spikes!

rgs UpperCut





 

UpperCut

Active Member
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Feb 11, 2016
Messages
71
Points
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Location
New Zealand
I really loved your previous speakers as well. Do you make them for others too on order ?

YES, can do! no problem as I have done so already before, but that was all on a private base of course I'm not a commercial entity - all DIY.

rgs UpperCut
 
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reubensm

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May 26, 2010
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4,884
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Trivandrum, India
stunning finish, well done.

a quick question, where the passives a part of the original design or did you customize?
 

venki7744

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Aug 25, 2012
Messages
102
Points
28
Location
Kerala
Hi UpperCut,

Fabulous job!! Love the build quality, do you mind posting instructions on how you went about fabricating the box. Something like detailed steps and the tool set used.

Thanks,
Venki
 

UpperCut

Active Member
Joined
Feb 11, 2016
Messages
71
Points
33
Location
New Zealand
Hi UpperCut,

Fabulous job!! Love the build quality, do you mind posting instructions on how you went about fabricating the box. Something like detailed steps and the tool set used.

Thanks,
Venki

Hi there Venki,

Well, as you know I use the slice building method (as seen in the first Images send - above) which I call I.S.C.T or the Innovative Slice Construction Technique(s).
You simple think of a shape work out in a round about way the width, length & height and have an idea what volume you want to have suited to your speaker chassis. First you draw your shape make a solid template for the 1st & 2nd top & bottom plates then make a second template from the very first one again, but now with the cut out(s) for the volume (with this one you have to make sure that you have in the REAR enough wood left to function as a simple counter weight against the speaker chassis weight in front as otherwise IF NOT done so it would be very heavy in front and very light in the rear which is not what you would want.

Now once you have this volume template (you can do this with a computer calculation or if you cant out whatever reason use water to work out the volume of that particular one slice. Well, done that calculate the 1 slice volume times slices like say 17 = total volume.
So 2 top slices + 17 volume slices + 2 bottom slices = a total of 21 slices all more or less from two templates.

All strait forward really! I use just normal tools as everybody like drill, hand router, sander and so on, but I have build myself a router table / bench were the heavy duty router (1/2 inch drive) is permanently mounted from below, and I bought a oscillating sander unit which comes in handy when you try to make different shapes well, and that is actually all. Once I have made the templates I use a nail gun to attach the template to a new pre-cut piece of MDF wood then I rout that one exactly to the template on the table router set up.

Once you done all the slices assemble them and check everything. There is an easy way of assembling all which will help when gluing. Start by using the second top plate nailing the first volume slice to it, but from the top slice then turn the two slices around and nail the next volume plate to the first volume plate and so on right down to the first bottom plate. Once you have all slices together remove each one again without damaging anything and keep the nails in each plate strait.
Now when start gluing do the same as before and the nails will be the guides so you assemble and glue first top plate + first volume plate + second volume plate .. Do not glue the first bottom plate, but use it to put pressure on the whole unit to dry after gluing.

Rout your holes for the speaker(s), PRs Etc.

My personal idea of building is to give it time and do not rush anything as new ideas will come with it along the way not necessarily to be used in that project but maybe in a next. To make sure that the outside will look not only good but perfect on MDF you take time and many coats of primer, sanding sanding filler filler sanding many-many times before even starting to paint as such and even then when the first coat is of colour you will find problems so touch up with filler again & again sanding again and the have a new colour coat.

This project here had 5 primer coats and 7 colour coats (Melon Yellow only) it is work which will be greatly rewarding IF YOU TAKE TIME!

Do not use nails in areas were you want to rout later! I use wood doles in 10 or 8 mm in holes which I had placed in the template and drilled in all others. Wood doles are fine in areas were you rout as they just get cut out in that area yet stay in the rest which is not cut Etc.

Hope this is helping you a little, but if anything else please do not hesitate to ask.

rgs UpperCut

PS: As you can see I do not use wood screws at all I do use cap screws for both the PRs as well as for the speaker chassis. Here you see the inner De-Coupling - Mounting plate which is using rubber inserts with a 5 mm threaded nut.

 
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UpperCut

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Location
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Every build eventually must come to an end & with that this one was quiet tricky and challenging, but I enjoyed all of the many stages very much.

First time fully assembled & everything does fit perfectly!
Just a shame that I have only one brand new 10 inch PR left in store & another defect one so I guess until the new ones arrived (once ordered) it could spring into action, but until then I will leave the defect one fitted and see what will happen when running it.

So presently not much more left then Artwork and waxing it nicely to avoid any marking as the charcoal colour as that is just showing up everything & I mean everything even when touched without been treated. Oh yes of course just remembered the bottom plate with the spikes is still to be done!

rgs Upperut

 

UpperCut

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Feb 11, 2016
Messages
71
Points
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Location
New Zealand
Looks stunning IMHO. Let us know how it sounds too.

Well, after waxing the enclosure nicely, and reconnecting all the electronics this speaker chassis type will run with - also in my 'I.S.C.T - The compact *Musical Box* project .' http://www.hifivision.com/diy/63159-i-s-c-t-compact-musical-box-project.html - I had it connected this afternoon and now I feel truly sick!

This set up is quiet mean say the least (I had it already run in for some time weeks ago so I chose a couple of B-Tribe & three albums (Global Spirit & Secret Of Live & another) of Karunesh for playing / testing, and well my head was spinning as it was extremly powerful and with that very LOW!

When I developed this unit I calculated / worked it out that it would reproduce in the low 30 Hz. Tomorrow I will run Sweeps so to get a better idea, but all in all it was truly mean even with other program material.

rgs UpperCut
 

UpperCut

Active Member
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Feb 11, 2016
Messages
71
Points
33
Location
New Zealand
Hi there once again,

Have to say that I personally & by my own opinion like these larger Spikes more!

Another idea on this one was to actually make it active and I started to look into that as the bottom plate I found could be suited for that as well.

rgs UpperCut

 
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