Old fashioned 12inch 3 way

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Dr Bunsen Honeydew
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#1 Old fashioned 12inch 3 way

Post by Dr Bunsen Honeydew »

Things always go quieter in the summer so I try to give myself a fun project. Based on Doc Mods concepts and not a NVA project and will not be commercially available so I will talk through the build here.

Drivers already settled on, my usual choices of 12 inch doped bass 4.5 inch doped mid 25 cm tweeter (my cheapo Chinese one I rebuild and dope).

Cabinet - choice of steel lined MDF, Marine ply, or just steel. I am wanting to do a welded steel cabinet of 6mm plate, finished and sprayed black like a car. I will look into the practicalities.

I would have really liked to use a 15 or 18 inch bass driver, but I wouldn't be able to move them without a hoist or crane.

Of course infinite baffle / acoustic suspension. Here we have a design of speaker that has completely gone, only examples are vintage now. I thought of doing it as a large Cube but I want to get as original to concept as possible with an updated, my ideas version of a Goodman Magnum or Wharfedale Dovedale. I may take the route of buying a cheap pair of either of these to use as the base as I did with the B&W just heard at Owston. BUT for the mo I want to explore the possibility of a steel cabinet.

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jayman67
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#2 Re: Old fashioned 12inch 3 way

Post by jayman67 »

how thick would the steel be?
having the panels laser cut to size would be best i reckon then welded up.
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#3 Re: Old fashioned 12inch 3 way

Post by Nick »

Will be interesting. The speakers at the weekend have already got me and Mark having conversations about what sort of driver available now would work well in a sealed box/
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#4 Re: Old fashioned 12inch 3 way

Post by Dr Bunsen Honeydew »

karma67 wrote: Mon Jun 12, 2017 5:54 pm how thick would the steel be?
having the panels laser cut to size would be best i reckon then welded up.
At the mo I am thinking 6mm. I was thinking of getting a local car accident repair place to knock them up but 6mm is a bit thick for them.

Any welders or metal workers advice much welcomed.
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#5 Re: Old fashioned 12inch 3 way

Post by jayman67 »

as a welder fabricator we use a lot of 5mm steel plate which we have laser cut to make football dug-outs,turnstiles etc,6mm is ok too.
if you give me dimensions i can look into prices for you,the other way is to disc cut the sheet metal to size which is tedious.
perhaps we could do some kind of deal? id like a external power supply for my turntable motor made,would you entertain that?
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ed
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#6 Re: Old fashioned 12inch 3 way

Post by ed »

how about :

celestion K12H-100 or 200
eminence beta 12LT
audio nirvana super12 CF

with the exception of the AN they go in relatively small cabinets and are reasonably cheap. The AN is neither small cab or cheap though. Perhaps a big risk.

I have no experience of either but they look promising

for a bit smaller the seas FA22 used to be really good vfm but the price is up a bit now. I do know this one works very well in acoustic suspension


just a couple of suggestions

I like the bass in acoustic suspension it particularly suits the SE valves and F2 but I haven’t tried the F2 with a 2 way.
as rough.jpg
Last edited by ed on Mon Jun 12, 2017 6:26 pm, edited 1 time in total.
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shane
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#7 Re: Old fashioned 12inch 3 way

Post by shane »

When you add steel plate to a conventional cabinet, the cab stops the plate from ringing. How will you do that for these? Damping pads or bracing or what?
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Dr Bunsen Honeydew
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#8 Re: Old fashioned 12inch 3 way

Post by Dr Bunsen Honeydew »

shane wrote: Mon Jun 12, 2017 6:19 pm When you add steel plate to a conventional cabinet, the cab stops the plate from ringing. How will you do that for these? Damping pads or bracing or what?
Wait and see. I may line the cabinet with MDF :lol: I am hoping it will need nothing, it shouldn't IMO even though convention says the opposite.
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#9 Re: Old fashioned 12inch 3 way

Post by Dr Bunsen Honeydew »

Ed - I am happy with the drivers I have for the project.
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#10 Re: Old fashioned 12inch 3 way

Post by Dr Bunsen Honeydew »

karma67 wrote: Mon Jun 12, 2017 6:13 pm as a welder fabricator we use a lot of 5mm steel plate which we have laser cut to make football dug-outs,turnstiles etc,6mm is ok too.
if you give me dimensions i can look into prices for you,the other way is to disc cut the sheet metal to size which is tedious.
perhaps we could do some kind of deal? id like a external power supply for my turntable motor made,would you entertain that?
Depend what you mean by power supply. Nicks one seems to be a regenerator, I wouldn't do that, though I am sure it works very well. It is just it would mean a design process I don't have time for. I use a BMU (balanced mains unit) on my TT (direct drive Pioneer PL71) and it does the job very well.

I am always into bartering :mrgreen:
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#11 Re: Old fashioned 12inch 3 way

Post by ed »

what about aerolam like was used in the celestion sl600.
Would this have similar properties to steel.
Is it still available?
is it workable?
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#12 Re: Old fashioned 12inch 3 way

Post by ed »

Dr Bunsen Honeydew wrote: Mon Jun 12, 2017 6:40 pm Ed - I am happy with the drivers I have for the project.
Apologies, I was addressing Nicks post where he says he was discussing this with Mark and wondered what was available nowadays.
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#13 Re: Old fashioned 12inch 3 way

Post by jayman67 »

Dr Bunsen Honeydew wrote: Mon Jun 12, 2017 6:45 pm
karma67 wrote: Mon Jun 12, 2017 6:13 pm as a welder fabricator we use a lot of 5mm steel plate which we have laser cut to make football dug-outs,turnstiles etc,6mm is ok too.
if you give me dimensions i can look into prices for you,the other way is to disc cut the sheet metal to size which is tedious.
perhaps we could do some kind of deal? id like a external power supply for my turntable motor made,would you entertain that?
Depend what you mean by power supply. Nicks one seems to be a regenerator, I wouldn't do that, though I am sure it works very well. It is just it would mean a design process I don't have time for. I use a BMU (balanced mains unit) on my TT (direct drive Pioneer PL71) and it does the job very well.

I am always into bartering :mrgreen:
when i say power supply i mean to power my rock 2 tt, it uses the typical linn premotec ac motor,something along the lines of this, http://norton-tech.co.uk/AirPower/APKit.htm
with that said if its grief for you no worries.
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#14 Re: Old fashioned 12inch 3 way

Post by Nick »

I am always into bartering
Ditto, though I have more on than time in the day at the moment. Thinking about using the FPGA for delay has split into another interesting idea for it. Must get that 64 bit linux box built up.

Sorry, this is even more off the topic :-)
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#15 Re: Old fashioned 12inch 3 way

Post by Dr Bunsen Honeydew »

I would still prefer a BMU, it sorts out the mains far better IMO. The advantage of a BMU is you can run and improve your whole system with it.
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