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My Dads homebrew uni speakers, need to build cabinets

pingu_turbo

On a constant search...
Good evening folks,

I was going through the loft the other day and I came across these. I remember as a child Dad used to hook these up every now and then for a little fun. Probably to piss Mum and the neighbours off.

From speaking to him about them recently he built them during the early 70's whilst he was in residence at university cutting his teeth on his trade to be.

I also remember Dad lending them to my school for various functions, discos and the like. They used to belt out one hell of a sound!

Anyway I came across them the other day and the memories came flooding back! :)

Unfortunately during the mid 90's when the extension was built on the house Dad had to either break them up or throw them away because of getting them out of the loft again. I remember the sad look on his face when he had to take them apart, to what I have left now.

So without further a do here are some pics \/ Here one is stood next to a Leak Sandwich (larger) and a Wharfedale melton 2 speaker. It stands in at 45" tall and weighs 50lbs, bearing in mind this is just the 3 drivers and a bit of chipboard.

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The mid \/
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The tweeter horn
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The woofer, I love the basket, beautiful quality casting.
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The crossover \/
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So what I ultimately want to do is finish off his work and build a cabinet for these wonderful drivers.

My background on speaker building is zilch. I have never built a speaker cabinet in my life. I am used to wood and metal work through my experience in various trades.

What I would like advice on is how I can calculate what size/type of enclosure I will need, ported/sealed etc. I was wondering if both the mid and woofer needed to be separated in the cabinet, like two enclosures in one box?My only real concern is the bass driver. There is very little information on it at all, as to what it is and what it is capable of.

Also I want to build a new crossover/s for the drivers.

To finish off I did bring them down from the loft this evening. I had to solder up a few connections but essentially everything works as is. I must say those horns sound truly amazing, even as they are!

Then I just need a mother hubbard of an amp to power them.
 
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Awesome Potential

I would not worry about trying to do the math to match the drivers. I would build a medium density fiberboard cabinet 12" deep. Put a ceiling and a floor, also of the same MDF, above and below the horn. Seal the chambers (with silicone at the joints) for each large driver, and then add a port tube facing forward in each sealed chamber.

Tune each chamber by sliding the port tube in and out, until the best sound is achieved. Have only the driver you're tuning make sound while you're tuning it. Cut the tube to length when satisfied, then mount the tubes permanently with glue.

A ribbon or dome tweet in the mid section might compliment the horn.

Just my 2 cents. :music:
 
Thanks for the reply BigElCat. I was going to say that 12" depth isn't big enough for the horn, but it is only 10" long, just measured.

I did think about adding a dome tweeter or a 6/8 incher to compliment that area. It seems a massive jump from 12" mid to horn.:scratch2:

I really need to learn about crossovers too, I have recapped many. But the actual science behind them is a bit of a mystery to me. I think I need to go back to school.:yes:

I was also thinking of building in real wood too rather than mdf. Would that sound nicer?
 
dont build with real wood. it changes density depending on the humidity and the temperature so the sound is not consistent. mdf doesnt do that. big elcat seems to be on the right track :yes:
 
Those are some sweet drivers in there. Keep us posted on your build.

Thanks, I wouldn't know how they stack up tbh. I guess my old man did well then all those years ago? :)

With regard to the build I will keep you posted, it is going to take some time though, they are monster cabinets. Will require some saving of pennies first! ;)
 
I HATE to step on anyone's toes here, but what has been suggested won't work well.

The first thing I would do is talk to dad and ask him if he followed a plan (that maybe came with the drivers) when he built the boxes. Drivers need a specific cabinet size to function properly.

I'm sure that if you do a Google search, you can find out info on the drivers. Goodmans are very nice and popular drivers. There should be alot of info on the net about them. The EMI might take a little more work to find, but between the members here and the net, info will pop up.

As far as the x-overs, they look like quality parts. The only thing I would change are the caps. At 30+ years old, they are probably out of spec.

Try PartsExpress for replacements. Look at Poly or better caps. Stay with the same mdf (uf) values, and at least 50v or more. Stay away from the regular, cheap ones. Good drivers deserve better.

I'm sure someone else with more knowledge will chime in. Be patient, and you'll have the answers soon enough.

Good Luck
Merry Christmas
 
dont build with real wood. it changes density depending on the humidity and the temperature so the sound is not consistent. mdf doesnt do that. big elcat seems to be on the right track :yes:

While I was reading that, I kinda figured that out. At least the mdf is consistently the same density, I'm afraid veneer is going to be an absolute must for these then! :)
 
Negative on the real wood.

The resins in MDF make it much more acoustically dead that actual wood. Most people then use a real wood veneer over the MDF.

Real wood is also subject to warping with age.

If you don't have experience with wood veneers, you could just use a sealer coat then color coat with paint. They're so large, I'd suggest a color other than black. Semi-Gloss taupe or mauve, with a clear acrylic top coat. Depends on your decor.
 
Yes talk with your dad about the original plans and what he thinks. Then get the drivers perimeters measured or buy the stuff to measure them yourself. Try to find out what frequency range each driver covers well and form a plan from that. If you post the driver parameters here several of these smart dudes can point you in the right direction. Without this info you are shooting in the dark and will never see the potential of the speakers and loose interest. Do the math up front, it makes all the difference.
 
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Sealed chambers would be superior to the port tuning I suggested. A 12" or 14" depth would give you a starting point. I assume the other front baffle is the same size as the one in the pic?

The two large driver would need to be isolated. Just set the inner ceiling and floor to make each chamber the right size.

Paint may sound like a 'cheesy' idea for a speaker, but you can always repaint to match or compliment a room. Those things are massive, and will be a major focal point in any room. Repainting is easier/less expensive than changing finish on a veneer. I'm not arguing against veneer. Birch veneer will accept any stain coat.
 
Omg, I think I have kicked a wasps nest, in a good way. :) If you get what mean. That is even better info there cablephil. I will download it in the morning. It's late here in the uk, I will undoubtedly be woken up at stupid o clock by my little girl, bouncing around like a coiled spring at the contents of her stocking & sack. I love Christmas. :)

Thinking about the styling of the proposed cabinets I was thinking of a wharfedale w70 style, with kinda built in feet. I love that era of style. :) but I'll see.

Thanks also for the build tips, I like the sound of that already. I am unsure about ported or sealed, I have never really made friends with a sealed speaker yet.

What I would like to know is if those emi drivers will go down to the low 20s. That would make my day knowing the spec on those. :)

Merry Christmas everyone!
 
Well having done a little googling on the crossover I found that 'dn12 crossover' belongs to the KEF Concerto.

(11173)_kef_concerto_b.jpg


Here is my crossover.

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One from google.

$(KGrHqV,!iUFB71EtbRbBQjrmF(jV!~~60_35.JPG


It looks like my EMI woofer comes from a EMI 315 speaker or a EMI Benjamin 300. I cannot seem to find much information on it though, but what I did find was the dimensions of the cabinet it was paired with.

EMI 315 huge enclosure 37 x 25 x 13 ins, effortless, awesome bass from EMI 315 15 inch woofer, 2 x 5 ins. squawkers, 2 x 3/3/8 baffle tweeters, recommended for low volume dance music.

This could be what I am looking for?

I also found this ebay listing here

Still looking....
 
Inside the EMI benjamin model 300.

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Definitely my woofer there, I just can't find much on the speaker itelf. :(
 
Well having done a little googling on the crossover I found that 'dn12 crossover' belongs to the KEF Concerto.

(11173)_kef_concerto_b.jpg


Here is my crossover.

DSCF7667.jpg


One from google.

$(KGrHqV,!iUFB71EtbRbBQjrmF(jV!~~60_35.JPG


It looks like my EMI woofer comes from a EMI 315 speaker or a EMI Benjamin 300. I cannot seem to find much information on it though, but what I did find was the dimensions of the cabinet it was paired with.



This could be what I am looking for?

I also found this ebay listing here

Still looking....

HOLY COW :yikes::yikes::yikes:

That's 7cu' of cabinet there.
 
Thinking about the styling of the proposed cabinets I was thinking of a wharfedale w70 style, with kinda built in feet. I love that era of style. :) but I'll see.

i like that idea and you might just find some nice gutted cabs like that for cheap.
 
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