Well, many months later, not only I found the factory, I got them to improve it!

Nothing was done to the drivers so the excellent tone still remains but the frame has been improved upon. From its initial stamped frame basket, it’s now an alloy cast frame.

Big deal you ask? Yes, IMHO it IS a big deal!

Hear me out first. Over the years I have played with all sorts of speaker drivers. My hifi journey began with a PSB bookshelf which uses Vifa and Scanspeak drivers. When I went into the world of low powered amp + high sensitivity speakers, I got a pair of Hammer Dynamics which was really pleasant to listen to.

Then later, I got into the amazing world of Coral drivers and I played and lived with so many of them, all the way until the top of the range Coral Beta series.

Today I have moved even higher up the chain (and my finances further down the red line) with the amazing, but expensive, Feastrex drivers.

So what have I learned all the way?

You can distinguish the top of the line, the best sounding drivers, in a company’s line up just by looking at the frame — the usage of alloy cast frame.

Huh? What’s the big deal?

Not only an alloy cast frame cost more than stamped baskets, it’s structurally a lot stronger too. And this translates to lower distortion especially at loud SPLs.

Besides if you have been in audio for a while, you also know that one of the first “test” and audiophile does to an amp chassis or loudspeaker enclosure is to give it a little knock with his knuckle. Why? To check if it is sufficiently dampened and will not “ring”.

Hey, ever notice how does a diyer tweak his speaker drivers?
1. dampen the frame with bitumen.
2. dampen the frame with rope caulk.

For what purpose? To strengthen the frame as well as dampen the frame from “ringing”. And stamped frames will ring! A gentle tap and you could hear it go “tinggggggggggg”….

All this is in theory but we have listened to the prototype and it’s bloody obvious it’s a huge improvement!

Full specs of the drivers can be downloaded here.

When I was at the factory, I was shown this excellent 1″ {jcomments off}silk dome tweeter. The build quality is really something! Puts many of the regular offerings to shame. And I was told this silk dome tweeter sounds really excellent. Some companies take this product from him then mark up 10x to sell. Hmm…

Took some back and listening test shows it’s really good!

From now till 31st December 2010, all 3 drivers will be at a special introductory price. Get them quick!

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Speaker Fetish!

So since I moved to this nice little shack here last year, I’ve been active with speakers! Actually not just me. Partner in crime, Master Speaker Builder — Gabriel, is guilty too!

I don’t know about you but surely one pair of speakers isn’t enough! There’s many other technologies to explore too! These drivers, 16 of them, were bought through the world’s Marketplace – Ebay, from David Dlugos. You may know him from the Transmission Line Speakers website. David also lists many amazing speaker drivers for sale on Ebay — a credit to the DIY Audio industry. I don’t know how he sourced for these treasures but I’m really grateful that he sold me these Monsoon electrodynamic planar panels. These were originally part of a computer speaker package. You need another driver for sub 200Hz (yes, these amazing panels go down that low) but as you can see, I haven’t gone there yet. As they are dipoles, and meant for near field listening, some cancellation occurs due to the rear waves “wrapping” the front. This cuts down the 200-1000Hz response. Thus I actually need a baffle 4 times larger. Hmm… maybe I’ll do this with acryllic? That said, what I heard so far was the most satifsying mids and highs ever (even though they don’t go that high). The sound is very transparent, very smooth and very “open”. Rather than the “speaker disappearing act”, what we have here is more of a “room disappearing act”. Very good potential for more messing around! Once I get back my SPL meter, I’ll widen the baffle and add a sub-200Hz driver. Stay tuned!

Inspired by the Hedlund, our intrepid Diyer Gabriel tried his hand at horn design and this is the excellent St Cloud! Named after his son (lucky kid!), St Cloud has only one bend too, like the Hedlund. Believe me, Mr Hedlund is right in insisting on just one bend. Just one word describes it best — Coherence. Note the compression chamber! At time of writing, Gabriel is trying out different drivers, hence the removable front baffle, which he HAS to route it nicely as well. I can’t remember which 4″ driver is this but St Cloud managed to pump out those heavy R&B bass notes from these puny paper drivers! Gabriel also tried with the Jordan JX92, and went head over heels!

Surely no Diyers’ home is complete without a home theater! My Grand HT Plan was to build 5 speakers with each enclosure utilizing a pair of these Aurasound NS3-194-8E, thus I bought 10 of them but when it came to building them, I realized my Home Theater corner is not really that huge. Must be all that Stout I had the previous night… So the Grand HT Plan shrinked to the Tiny HT Plan, reducing the number of speakers from 5 to a much more manageable… 2. Consulted Gabriel and he suggested 2 liter volume for each driver, so the box was built for about 5 liters. I had to build bigger as due to my “excellent” woodworking skills, it’s better to err on this end. What can I tell you about the sound? It belies its size! Though the driver specs not much output below 150Hz, I bet there’s at least 80Hz down there. I know, not sufficient for HT but we are getting an awful lot of mileage here! The sound stage is wide and opened, and I had no issue with “rough highs” even though they weren’t 100% aligned vertically (it’s really not easy to cut the holes right) nor as close as possible. Who cares? Allison Krauss is happy singing, T-rex is happy crunching bones, my wife is happy with 5-reduced-to-2-speakers, everyone’s happy! See those 15″ drivers? No, no, no. I wasn’t trying out a bass driver. Was testing them for a friend.

As you can see, speaker building is a lot of fun! Besides anyone looks cool sawing wood! I hope you’ll build some speakers now.

As for me, it’s time to plan for… more speakers!

Bass module for the Monsoon planars, a horn subwoofer for the Aurasounds…

diyparadise.com

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Coral Speaker Drivers

Clockwise from top left: 8A-40, Flat 8, Flat 6 and Beta 6

I’m sold out on ALL Coral drivers. Whichever driver is still available on sale will be shown in the e-Store, so do check out there.

 You could also find relevant Coral information on my Flickr page.

And on the seventh day, God created Coral Speaker Drivers.

Okay, okay, I’m full of bull here but these are, in my unabashedly unashamed opinion, one of the best speaker drivers around.

Rear view.

First things first, please stop writing me to enquire about Flat 8 drivers as I have sold all of them. No more. Finito. Finished. If you missed the boat, don’t be slow again! [If you have to ask me about availability of the 8s, give me your address first, so that I could drive to your place, and clobber you to dead with my pair of 8s.]

As you may still not know this (where have you been?), the Coral Audio Corporation has ceased operation in the mid-80s. I was told they were bought over by Mitsubishi Corporation. Which must be a sad day for the audio world as these wonderful drivers made more than 25 years ago are not only beating the shit out of MOST contemporary drivers TODAY but also amazes us at how well they withstood the test of time!

If you have no idea what how long that was 25+ years ago, consider this:
The King of Pop was Black.
US of A has a former actor as the President.
The British PM wore a skirt.

Today, we are not sure of all three!

Considering back then, without the aid of Computer Aided Design, it was really marvellous speaker drivers of such quality was designed and manufactured. I’m sure you must have read all the problems with single drivers on other forums, like lack of bass, thin-hollow sound, rising frequency response, surround needs changing every few years.. Plus all sorts of tweaks to improve her performance… Well, I don’t find a need for all this work! [Though adding a phase plug did bring an improvement.]

Now isn’t this amazing?! How did they do this back then? What has 25+ years of technology and R&D later give us? Boy, I sure wish I could talk to a former Coral engineer to learn more about this amazing company!

DIY Paradise has been extremely privileged and grateful for the opportunity to discover this warehouse of a former Coral distributor, and as such, have been selling these full range drivers for the last 2 years. To date, I have sold over 50 pairs of Flat 8s and 60 pairs of Flat 6s! Imagine New Old Stock vintage speaker drivers!

Differences in cone, whizzer and surround construction.
Left to Right: 8A-40, Flat 6, Flat 8, Beta 6.

So grab them while you still could!

Flat 8. SPL 95dB. 40-20000Hz.   [NO LONGER AVAILABLE]
Flat 6. SPL 92dB. 45-20000Hz.   [JUST SOLD OUT! Have some B-stocks though. Please write to enquire.]
8A-40. SPL 93dB. 40-18000Hz.   RM400 / USD115 a pair
Beta 6. SPL 93dB. 40-20000Hz.   RM1600 / USD460 a pair

Without a doubt, the Betas are the flagship models. The basket is diecast, instead of stamped. The ribs reduce reflection and look at the mojo binding posts!

Enclosures
I have had the privilege to listen to various Corals in bass reflex, sealed box, TQWT, spiral horn and the Hedlund horn cabinets. Out of all these, it is without a doubt the best sound came from the Hedlund horn. The spiral horn is pretty amazing too and it sure doesn’t take up much space! If you aren’t horny, here’s some enclosures.

Some of the designs I have played with.
Beta 6 in Hedlund horn, Double Flat 6s, Waily’s Flat 8 (i built this too), Flat 6s in Spiral Horn (i fitted a phase plug).

Feel free to write me if you want your own spiral horn for your Corals.

Search more info on Coral speaker drivers on the Net.

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