Old Coral kit speakers

[THOMO]

I recently bought a pair of 1970s Coral speakers from a local second hand shop.

I was familiar with these because my older brother bought them in kit form and made boxes to suit back in about 1975.

They consist of a 12 inch woofer,4.5 inch mid and two cone tweeters.All light paper cones.

Has anyone else had a play with these?

From my initial listening I believe they have serious potential.

Of course you need to hear past the unfortunate combination of unbraced chipboard boxes,non mirror imaged tweeter/midrange position,20mm recessed front baffle and very old and basic crossover components.

So the imaging is a bit diffuse and the bass a bit boxy but they also sound very clear,fast and detailed.They are also very easy to drive and sound excellent with my Sonic Art Legend single ended ECL86 valve amp which outputs only 3 watts per channel.

I am planning to try to get these sorted by making new cabinets,mirror imaging the driver layout and upgrading crossover components[easy to do as they appear to be simple first order].

I have already found that replacing one of the cone tweeters with a Fountek JP2 ribbon tweeter has improved the sound signifigantly so I will also add these to the mix.

Am I wasting my time and effort?

[Jake]

Talk to Grumpy, he's a fan of Corals. I think he would say yes, they are worth the effort.

Cheers,

Jake

[kye]

I have heard some "fullrange" (ie, wideband) coral drivers - I think they were 8" but could be wrong, and while the frequency extremes were nothing to write home about the mid response was very nice.. If I had to do a fast speaker on a budget a pair of these would be my midrange drivers.

Be careful doing too much too them to make them the "best of modern design" as speakers like this were designed around synergy with the mechanical resonances of the box etc..

I would suggest a good crossover, a light box (perhaps made of ply) that is roughly the same dimensions as the original one (width is an important thing here) and see how you go with that

[Tony M]

Hmm, at my mum's place are a pair of speakers branded "Coral" that look like a 70's local manufacture with imported drivers. I don't seem to remember them sounding particularly good, but this could've been for a variety of reasons. I know they were bought secondhand in the late 70's and have been gathering dust as "part of the furniture" in a reasonably well-controlled temp and humidity environment since then. It's several decades since I had a peek inside, but your description of the driver size/configuration rings some bells.

So, Thomo, I'll be watching your progress with interest. If your resullts are encouraging, these might be a worthwhile project if and when some time for playing with hifi becomes available. I'm sure "the old dear" would be happier with a bit of nice furniture than the remnants of my long departed father's passing interest in hifi.

I guess a lot of "old chooks" are in the same boat with hifi gear from past decades gathering dust in dark corners of their home. Most would have no interest in attempting to use it but little motivation to get rid of it:rolleyes:

Cheers

Tony

[Grumpy]

Yes I was given an old pair of Corals and re-built them a little.

They were a little short, so i built a false bottom and used thin stained plywood to recover them over the top of the chipboard. Also put new wiring and bracing inside, but I know nothing about electronics so the Xovers stayed the same. The mids fell to pieces so I put different mids in them inside a sealed upper enclosure.(I still have the original plastic mid tube enclosures in the shed) The sound did improve with all the little improvements and those big 12' woofers behaved themselves better with the bracing and a little more volume because of the extra bottom I built on the cabinets. Oh I put spikes on them also which tightened up a bit too.

When I bought my VAF DCX's I took all the tweeters and mids drivers out of the Corals, sealed all the driver holes and installed a Jaycar 350w sub plate amp into the back, layed it on it's side and used it as a subwoofer. It sounded amazingly deep and tunefull and could really rattled my lounge room windows. Unfortunately the woofers could not play 'Darkside of the Moon' at high volumes, but it was fun.

So! biggest improvements that i found;

spikes,

bracing,

extra volume and height by building the boxes about 25cm (10") higher.

This was the finnished Corals.

[Grumpy]

Oh forgot to mention the sound;

Lush, Mellow, Smooth, Deep, engaging, non fatiguing. In fact I never had listening fatigue with them and I use to 'meditate' while these lovely speakers washed the sounds over me; Gee i miss them.

I still have the drivers and Xovers, so i suppose i could do a rebuild!

[THOMO]

Grumpy,

Yes the same drivers by the look.

I strongly suspect that with some careful modifications these will leave the VAFs for dead-not that the VAFs are not good speakers.Just that these old low power,light paper coned,high sensitivity Japanese drivers can sound stunning when care is taken with crossovers,boxes and layout.And when you use them with simple low powered valve amps.

Coral made some of the finest drivers ever.The Beta series full range drivers continue to attract very high prices for example.

Interesting comments about the woofers.Certainly even in my crappy chipboard box they sound very quick and textured.I have them on stands.

Edited December 20, 2008 by THOMO

[nrand]

I recently bought a pair of 1970s Coral speakers from a local second hand shop.

I was familiar with these because my older brother bought them in kit form and made boxes to suit back in about 1975.

Am I wasting my time and effort?

From memory these came from Nigeria. I had a pair of Coral monitors, each with twin 6" cones in a bose-esque configuration, They were tough as nails - I think my daughter still uses them for bass guitar practice at home. I used to like listening to things such as Nirvana - really cranked - they loved being pushed.

[Grumpy]

The Coral hi-fi speaker kits of the 70's came from Japan and cost $207 in 1974.

[THOMO]

From memory these came from Nigeria. I had a pair of Coral monitors, each with twin 6" cones in a bose-esque configuration, They were tough as nails - I think my daughter still uses them for bass guitar practice at home. I used to like listening to things such as Nirvana - really cranked - they loved being pushed.[/quote

I have to agree with Grumpy.These were not from Nigeria.

My mystery inheritance is coming from there though.

[Nedman]

This was the finnished Corals.

I have a set of them [without the extensions] with a matching set of seas kit speakers [same cabinet work] with two 10" woofers, from the 70's. I found them a lovely sounding speaker, and able to go very loud. But something went wrong with them . So I replaced them with a little set of Royd Minstrels, which are a lovely detailed speaker, but I do miss the sound of the Coral/Seas combination.

I still have them, with the plan being one day I might be able to fix them LOL

[Guest poynterama]

Sorry for dragging up an old thread! I have a set of Coral kits that look similar, if not the same, as those pictured. I picked them up a while ago from Robin-hobart, but haven't had a chance to rebuild the crusty old chipboard enclosures. Now that holidays are coming up, I reckon I'll get a chance! Grumpy- do you have plans of the enclosures that you built for yours? I really like the look of them and would like to get mine back in a usable state. I'll probably have to make some new crossovers for them, so any advice here would be appreciated as well!

Thanks in advance,

Sam

[Grumpy]

I don't have the original plans but i did right down all the measurements when I did the re-build; unfortunately I have no idea where they are now though.

Maybe by measuring the woofer in the picture, knowing they are exactly 305mm (12"), you could do a 'work-up' to scale from that?

The extra bottom i put on mine really did improve the sound, although the inside volume stayed almost the same because i sealed the mid and tweeters off from the woofers. The bottom, below the black face is the new bit made of 18mm MDF, the original box was chipboard of approx-15mm.

I braced the box at 1/3rd the distance from the top. The bottom acted as a brace itself with it being almost a sealed box with a cut-out to give it the volume it needed, roughly and I do mean roughly:rolleyes:

Hope this helps. AND Yes! I wish I still had them

[Guest poynterama]

Thanks heaps for that! Am I right in thinking that the extra section you added on the bottom had a port into the woofer chamber? I reckon I could make something close to what you've got based on the photos- it's certainly got me enthused about the project again!

[Grumpy]

Thanks heaps for that! Am I right in thinking that the extra section you added on the bottom had a port into the woofer chamber? I reckon I could make something close to what you've got based on the photos- it's certainly got me enthused about the project again!

I made a complete sealed box for the bottom section then cut a rectangle out of the top pf the box and fitted it to the top section with a similar size cut out in the speakers bottom. sort of like a enclosed port.

Oh! these are a sealed speaker too if you didn't know.

Sorry i can't be more helpful, but i don't know the tech side of speaker building; I just wanted to change the originals so i did.

[Guest poynterama]

I have a lot to learn when it comes to the tech side of things so I really appreciate any help!

I made a complete sealed box for the bottom section then cut a rectangle out of the top pf the box and fitted it to the top section with a similar size cut out in the speakers bottom. sort of like a enclosed port.

That's more or less what I was thinking, should be a fairly easy way to do it I reckon but my current chipboard enclosures are well and truly lunched (they were full of old undies and socks for dampening!) so it'll be all fresh MDF for me I think

[Grumpy]

I have a lot to learn when it comes to the tech side of things so I really appreciate any help!

That's more or less what I was thinking, should be a fairly easy way to do it I reckon but my current chipboard enclosures are well and truly lunched (they were full of old undies and socks for dampening!) so it'll be all fresh MDF for me I think

Oh yea, I lined the walls with foam sponge and added some pillow stuffing (the white fluffy stuff) The originals had the old flock gauze in it.

[Pops110]

Sorry to drag this thread up again, but one of my mates picked up a full NAD system, including 3020a amp, and a set of coral speakers, that look very similar to the ones mentioned in this thread, from roadside rubbish pickup.Everything works fine except one of the woofer dust caps has started to come away a bit and makes noise when played loud. What would be best to stick it back down?

Also the cabinets have seen better days, would it be worth while spending a few dollars and making some new cabinets and doing some mods to the crossover as well? They sound pretty good with the 3020a.

Cheers Dave.

[Grumpy]

Use PVA glue on the dustcap and Yes i think they would be worth doing up. They had a beautiful tone

Speaking of dust caps. My Corals developed a strange scratchy sound at higher volumes and I noticed the black mesh covering the hole on the woofer dustcaps had come lose and was vibrating causing the scratchy sound.. I removed the mesh with no more trouble or difference to the sound.

[Pops110]

Cheers grumpy, thanks for that. Problem solved, now I might try and find the time to make some new cabs, although my mates pretty happy as they are. See what happens.Cheers Dave.

[Brisso57]

Time for an update on an old thread ...

The kit that Thomo and Grumpy are talking about is a Coral 12SA-1.

Refer here : http://new-hifi-classic.de/Gallery_MO/displayimage.php?album=497&pos=11

I recently bought two pair of these kits in good nick. One pair was in quite odd home-made tall, skinny and flimsy cabinets. The other pair was in professionally made cabs, but ... 40-odd years down the track, the stuff-up at the warehouse has come to light. The cabs should be 55L, but measuring mine and calculating, I find 45L. It seems apparent that the 10" kit , which was 45L, had the same size baffle board as the 12" kit. The 12" cabs must've been deeper to provide the extra 10L.

Anyway, it's clear that the chimps packing the kits must have mixed up the components, hence my 12" kit in a 45L cab.

My purpose in buying 2 pair is to build myself an all-Coral surround system.

It should be fun.

... & they should sound great ... In the correctly sized cabs.

Cheers

Doug

[Tony M]

Thanks for that info update, Doug.

 

The least I can do is to provide some pics  of a 12SA1 kit, professionally assembled in the early 70's.  They sound good and look OK, but I rarely use them these days.

 

The box internal volume is 55 litres.

 

 

 

 

 

 

 

 

Hope these are of interest.

Edited September 14, 2014 by Tony M

[Brisso57]

Thanks Tony.

It's useful to see a few internal details. I don't suppose you kept the original kit paperwork? ;-)

I'll be using my Jasper circle-cutting jig to flush-mount the drivers on the front of the baffle. I'll also be using 18mm ply, rather than chip-board, and fitting a "holey-brace" behind the woofer.New XO caps too.

I think I'll run the wiring through the base and have the XO outside the box, where I can get to it easily (to play with component values).

cheers

 

Doug

[henry218]

Thanks Tony.

It's useful to see a few internal details. I don't suppose you kept the original kit paperwork? ;-)

I'll be using my Jasper circle-cutting jig to flush-mount the drivers on the front of the baffle. I'll also be using 18mm ply, rather than chip-board, and fitting a "holey-brace" behind the woofer.New XO caps too.

I think I'll run the wiring through the base and have the XO outside the box, where I can get to it easily (to play with component values).

cheers

Doug

The vertical brace will improve your box significantly, as well as some dynamat type of sound deadener for car to put on the Coral's stamped steel frame

[Grumpy]

Check the surrounds on the mids as they seem to be the ones that disintegrate first.

Tony have you had a play with yours recently ?

Edited September 15, 2014 by Grumpy