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RichardH

DIY cabs

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[quote name='Phil Starr' timestamp='1389745537' post='2337587']
This is the other main supplier [url="http://www.bluearan.com/"]http://www.bluearan.com/[/url]
[/quote]

thanks man,

think ill go the route of ply with a laminate top, hopefully can start building once ive been paid and get the main body of the cab done then grab speakers over a few months


andy

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Just wondering about the benefits of a cast aluminium basket. Fane make a good looking 10" Sovereign 10-300 and a virtually identical Sovereign Pro 10-300 and virtually the only difference is that the slightly more expensive Pro has an aluminium basket rather than pressed steel.

Edited by Chienmortbb

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The aluminium basket does two things potentially. It is more rigid than its steel counterpart and this might help in the longevity of the speaker. Ceramic magnets can be pretty heavy and the basket can potentially distort over time. The second advantage is that aluminium is a great conductor of heat and the frame may help in cooling the magnet and coil. This could mean less power compression as the speaker heats up. Notice the conditionals, maybes and mights. I've not seen any figures on this though Bill may have some sources to offer.

Generally I prefer to go for the cast frame although I've had few problems recently with pressed steel frames. Cast frames are always more expensive to implement and there are potential benefits so they are one indicator of a little more care in the speakers design/implementation. I'm using the Fane 10-300's with the steel frame in my stage monitors however with no problems at all so far.

Edited by Phil Starr

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[URL=http://s147.photobucket.com/user/van_donk_III/media/2014-05-17164204_zps22cd4546.jpg.html][IMG]http://i147.photobucket.com/albums/r309/van_donk_III/2014-05-17164204_zps22cd4546.jpg[/IMG][/URL]

Wheel boards are great things. All eminence speakers, was amazed at the punch, clarity and sheer output of volume from the Kappa 15" driver. Making the cabs a little bit deeper definitely helped to voice them along side the Theile porting.

Still looking for speaker grill material, but can't find any anywhere for sensible money.

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[quote name='Chienmortbb' timestamp='1408570103' post='2531524']
Just wondering about the benefits of a cast aluminium basket. Fane make a good looking 10" Sovereign 10-300 and a virtually identical Sovereign Pro 10-300 and virtually the only difference is that the slightly more expensive Pro has an aluminium basket rather than pressed steel.
[/quote]Aluminum is stiffer than steel, so it's usually used with heavier magnet structures that might cause a steel frame to warp. Aluminum is also used with higher power neo magnet drivers for its heat sinking properties, as neo is more sensitive to heat damage than ceramic magnets.

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[quote name='VTypeV4' timestamp='1380745072' post='2230040']
Just acquired these today..

[url="http://s778.photobucket.com/user/VTypeV4/media/WbinCelestions_zps9fcdf314.jpg.html"][/url]

They're in need of some restoration but their construction seems pretty solid. One has a serviceable (I think at least) Celestion Powercell driver with a big magnet and cast frame whereas the other has a knackered K15E 200. A severe voice coil rub and a caved dome probably will see it scrapped but we'll see.
[/quote]
Bit of a strange question, but you didn't buy these from someone in hucknall (nottingham) did you?

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Aluminium is not stiffer than steel and was used for loudspeaker chassis long before neo came along.

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Well I never, I was going to challenge you on that one Stevie but I checked, Youngs modulus for steel is 210,000 v's 70,000 N mm-2 for aluminium depending upon which alloy you are talking about. So you are right. However of course rigidity and stiffness are not the same and cast aluminium structures are thicker for the same weight so aluminium chassis may be more rigid even if steel is stiffer. It is certainly true that all the bigger ceramic magnet speakers have had cast chassis for the extra rigidity for years. Bill is right though, I think, about heat dispersion for neo speakers, their light weight would not need particularly good load bearing but it is difficult to radiate heat from small structures with a relatively low surface area.

[url="http://aluminium.matter.org.uk/content/html/eng/default.asp?catid=217&pageid=2144417130"]http://aluminium.mat...geid=2144417130[/url]

[url="http://en.wikipedia.org/wiki/Young%27s_modulus"]http://en.wikipedia.org/wiki/Young's_modulus[/url]

Edited by Phil Starr

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For those of you that have designed your own cabs, I have a few questions

I've been looking at some of the posts in here (I've not had time to read the full thing yet), and seen a few people with baffles in their cabs - what's the purpose, and is it necessary?
Sealing - what do you guys use? Just silicone sealant?
Joints - what type of joints are you guys using, and do you use glue, wood screws or both? I'm planning on using CAD software to design the cab, and use a CNC router to cut it out, so I'm thinking of using box joints to join it together.
Speakers - I'm looking at the Eminence Basslite or Celestion BN10-200x - anyone tried these, or got any suggestions for other neodymium drivers around £100?
Finally, I've seen a couple of posts about deadening (pillow stuffing etc.), is this also necessary?

Sorry if these questions have probably already been answered, and thanks in advance for any useful responses!

Edited by budget bassist

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Having spent a good while using WinISD to work out dimensions and porting etc. I've knocked this up in sketchup to get an idea. Still need to work out what I'm going to do in terms of internal bracing (any recommended reading?), but it's looking okay thus far. I decided to go with rabbet joints in the end, as I remembered half way through designing the enclosure with box joints that a router won't cut the internal corners properly. Shame, because it would have looked good.

[attachment=170444:bass cab 2.jpg]

Edited by budget bassist

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You can overdo the worry about joints, rabbets make it easier to clamp up but don't add significantly to the strength, there isn't a big increase in glue area, there are lots of successful cabs with simple butt joints for example.

My favourite for home construction is the reinforced butt joint with a 1" batten screwed and glued along all the joints. Screwing and gluing means no clamping increased strength and some damping of panel resonance and it is so easy. It was the recommended technique for years and even some commercial cabs used it when they were hand built. Almost any mastic is good for sealing joints, though if you do a good job should be unnecessary. The glue should seal everything. I use water based mastic because I don't like solvent fumes around expensive drivers but by all means use silicone if you leave the cab to air for a couple of days before fitting the driver permanently in place.

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Personally I prefer a 'heavy' 3/4" cab with minimal bracing to an extensively braced cab. Not that i think one is wrong and one is right but I'm less than convinced that the extra work is justified by the change in sound. There is very little weight saving if the bracing is extensive. One day I'm going to do extensive testing of this but I haven't so far. I'd stick to broom handle style cross bracing with only one or two across the panels. Keep them off dead centre, you are damping panel vibration as well as stiffening the cab and a central brace only moves the fundamental up an octave. Kind of like trying to damp at the twelfth fret and playing an accidental harmonic.

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I agree Phil. I prefer 3/4 Spuce ply to Baltic Birch. It is a little softer but easier to work and as you say 3/4" butt joint are better that 1/2". Spruce is 1/3 lighter that Birch so tye overall weight is the same.

I once visited one of the big PA hire companies when big bins were the order of the day. They spray painted the cabinets each time they came back from tours. Filled any dents, then sprayed the matt black so they looked pristine everytime they went out on hire.

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I've had a bit of a google, and according to a number of sources, the best/easiest way to do it may simply be to use wooden doweling, I think I'll go with a combination of this and 12mm birch ply. This [i]should [/i]give me a fairly lightweight and good sounding cab, I think.

Edited by budget bassist

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I have another question - I've been using WinISD and some other online speaker dimension calculators, and they're all throwing up rather large box sizes in order to get the optimum sound for a specific speaker, which I understand. But how are all the manufacturers using such tiny enclosures and still getting a good sound? I'd like my cab to be as small as possible really, I just don't understand how they're doing it.

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[quote name='stevie' timestamp='1409154458' post='2536899']
Aluminium is not stiffer than steel and was used for loudspeaker chassis long before neo came along.
[/quote] :) like comparing a steel and aluminium framed bike. Heat dissipation isn't as much of an issue on my push bike - but you can literally feel the difference with how they behave.
[quote name='budget bassist' timestamp='1409524872' post='2540616']
I have another question - I've been using WinISD and some other online speaker dimension calculators, and they're all throwing up rather large box sizes in order to get the optimum sound for a specific speaker, which I understand. But how are all the manufacturers using such tiny enclosures and still getting a good sound? I'd like my cab to be as small as possible really, I just don't understand how they're doing it.
[/quote] Bill FM will possibly maybe turn up and say that they're not! .... just a question... have you considered buying the plans for bill's simplexx 10? he'll have done all the design work, tuning, crossover design and testing for you....of course half the fun for you might be doing it yourself in which case ignore me!

and also the 3 musketeers on here are making a 1x12 with quite a low price (non neo) driver - which looks like a good build too

Edited by LukeFRC

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I have considered that, but as you said, half the satisfaction will come from having designed the thing myself! And fair enough, haha!

Another question, does it matter where the driver is positioned on the front baffle? Does it need to be perfectly central, or can I move it around a little?

Edited by budget bassist

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There are pracical reasons for cabs being under sized.

Portability, In my early days as an 18 year old student I built a mate an optimum sized cab only to find it wouldn't go through a doorway and we had to remove the sash windows to get it out of the room!

Tone, believe it or not an extended and full bass response often creates problems and isn't an unmixed blessing. To many room resonances excited. reducing the cab size will cut the deep bass and create a bass hump a bit higher up. This is the sound of most cabs and one we find pleasing, if a cab has a good 'thump' you can bet its the hump of an undersized cab.

Go into WinISD and you can change the box sizes and see how that changes the response. If you are unfamiliar with Win ISD the best way to do this is to open up a new project, input the same driver and then change the plot colour. Then change the box volume (try halving it) and both the original and half a box responses will be displayed on the same graph. You can fiddle with tunings and see what that does too.

If you want a flatt response in a small box then look for drivers where Qts is small and so is Vas.

Power handling is often slightly higher in an undersized cab

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[quote name='budget bassist' timestamp='1409524872' post='2540616']
But how are all the manufacturers using such tiny enclosures and still getting a good sound?
[/quote]They aren't. One doesn't have to go to the full optimal size for a driver, but one also should be judicious in how small one goes, as it does affect the result. OTOH most manufacturers aren't concerned with getting the best possible result, they're interested in sales. Average customers don't know anything about Hoffman's Iron Law, and think f3 is a note, not a marker of speaker performance. What they've been led to believe is that one gets the best results from stuffing as many drivers as possible into the smallest box, so that's what said manufacturers give them. Since these customers have never used a truly well designed and built cab they don't know the difference, so the cycle remains unbroken.
[quote]half the satisfaction will come from having designed the thing myself! [/quote]One might say the same about a hang glider. :blink:
Making an error with a speaker may not have as disastrous a potential result, but still you are asking questions that one fully prepared to design their own speaker would not be asking. If you're bound and determined to reinvent the wheel, and repeat the same errors made by all those who came before, you should at least avail yourself of resources such as this:
http://techtalk.parts-express.com/showthread.php?219617-The-Speaker-Building-Bible

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I appreciate the help, I know I'm not going to get it right straight away, and if that is the case, then I'll only have wasted some plywood and my own time. So no big deal really. I'll have a read of that link, I've been reading around, trying to get my head around the whole thing - I have a little knowledge of acoustics (and electromagnetics, which seems to cross over a little), the biggest hurdle to me is the terminology it seems! I'm not expecting to build anything amazing, but it's a decent little project to embark upon given the tools I have available. You might ask "why?". Well, why not? If what you're saying is true, then surely I can't do much worse than an ill-considered mass-manufactured box would be?

Edited by budget bassist

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[quote name='budget bassist' timestamp='1409576681' post='2541035']
If what you're saying is true, then surely I can't do much worse than an ill-considered mass-manufactured box would be?
[/quote]True, but what most newbies set out to do is to basically build the equivalent of an ill considered mass manufactured box, with the intent of doing so at a lower cost. In the end they don't save any money, while mass manufactured boxes aren't worthy of emulation. For that matter I can count on the fingers of one hand the number of boutique manufacturers whose cabs that I'd consider owning, and one of those I did the design work for. :)

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Well I'd better keep reading into it then, and hopefully I'll come out with something half decent! :)
To be honest, if I end up with something that sounds similar to my Ashdown kit but ends up a lot lighter, I'll be winning.

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[quote name='budget bassist' timestamp='1409581179' post='2541105'] if I end up with something that sounds similar to my Ashdown kit
[/quote]Setting your sights way too low you are. DIY isn't about equalling off the shelf, it's about kicking the snot out of off the shelf.

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