Yeah, this is the Kuala Lumpur International AV Show 2008. Our debut at an audio show.

Note that source is from the Mac Mini on the far right.

St Cloud and the Hedlund Horn. The St Cloud is more suitable for this small room but can’t play that loud due to its 3″ driver. Most of the time we play the Coral Beta 6 in the Hedlund Horn. Most folks when they see both speakers, ask for bass!

Closer look.

2 digital source is used alternately. The modified Squeezebox and the CDPRO2-based transport.

The top rack shelf is for signal path only. Bottom shelf for power supply. Each power supply has its own balanced isolation transformers.

The all-in-one. Perhaps should call it “All or Nothing At All”.

Requires a digital input and output goes to speakers!

The best interconnects are NO interconnects.

Enough about the system! My thoughts are blogged here.

KL International AV Show 2008 – First day

KL International AV Show 2008 – 2nd & 3rd days

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Blood, Sweat, Tears and a Bloody Tan
a. k. a.
How to Drive Your Wife Nuts

Congrats Mr Jan Hedlund for such a wonderful design! Mucho gracias, arigato, merci beaucoup, vielen Dank, thank you very much!

Thanks a lot too to Master Craftsman Gabriel who really has wonderful hands with wood!

Now, you may not know this but I have been really lucky. I mean really really lucky. I have been fortunate enough to listen to the Coral drivers in various enclosures. Open baffles, Sealed box, Bass Reflex, Mini-Array, TQWT, Spiral Horn and now, the Hedlund Horn. Each has its virtues but for sheer quality, the last 2 deserves special mention.

Why so? It’s a belief that paper drivers need special tender loving care, just like your long-suffering (in my case) better half. When a driver pumps out sound, there is a reverse wave that goes into your enclosure. If you don’t take care of this sound waves, it’ll wreack havoc every where especially when it bounces back to your driver and thus distort the intended sound. So how you deal with this backward waves in the enclosure, determines how macho you are! And when you have successfully dealt with this rear wave, not only your bass notes improve, the mids and highs improve as well! As there’s less “junk” to destroy everything now. Comprehende? And this is where horn designs are so highly prized! Due to the expanding volume from driver location to horn mouth, you now have a mechanical “amplifier”. The rear waves have an easier path to “get out”. There’s a lot more theory than this but my simple mind only permits this. : ) So Gabriel suggested building the Hedlund Horn and he helped me built it. Actually, you can almost say he built it! Parts where I “contributed”, he needed to do more work to undo the damage! I better stick to soldering… Macho men only need these tools to build…

When we started building, I envisioned the smooth curves will make a baby with high Wife Acceptance Factor. However, after it completion, this baby has grown to a monster! At 6 feet 7 and weighing almost 60kg, it’s no fun to carry around! Despite the horn length, the Hedlund doesn’t go below 50Hz. At least that’s what my measurement shows. 50Hz is still strong but below that, it drops like a bomb. That said, who cares about quantity when you have such quality! Listening is an experience itself!   Coral Beta 6 The Coral Beta 6s are no ordinary drivers. Designed more than 25 years ago, in my books the best speaker driver listened to! Listening to the Betas in the spiral horn reveals the best mids and highs I have ever heard! The level of detail and ability to convey the slightest of nuances in well recorded material is unmatched by any other drivers I have played with. With poor recordings, you don’t stand a chance though. Thus, With Great Drivers, comes Great Responsibility. Build a crappy amp, you are going to suffer. Build a crappy DAC, you are going to cry.

Thus we didn’t mind suffering in building the Hedlund for the Coral Beta 6. There’s definitely our blood and sweat in there! I suffered so many cuts and bruises and now the scars suggest I’m a veteran of many squabbles. So stay your distance ok? Tears came when we listened to her! Either tears of joy or tears of despair and fortunately, ours is the former. The tan? Well, no thanks to our Malaysian sun…

The sound?
Don’t ask! Build it yourself! Ha ha! Anyone who doubts single drivers can do bass opt to listen to the Hedlund. Although she doesn’t go lower than 50Hz, the quality of the bass is beyond compare! Fast, natural, distortion free and NO BOOM at all! In comparison, bass from non-horn designs sound “constipated”, sound “forced”! All this while maintaing the brilliant mids and highs of the Beta! Also, one of the pet peeves most folks have with single drivers is the “lightweight” sound, particularly the lower midrange. Fear not now folks! It’s not the driver’s fault but your enclosure! Male vocals have never sounded better!

The System as of March 2006

CDPRO2 feeds Monica2 with Grounded Grid tube gain stage, feeding Charlize, then the Beta 6s in Hedlunds.

Monica2 in GG with Amperex 5842s. Will be trying other high transconductance tubes soon!
Note I hate RCA sockets so am using XLR now.

Charlize in a simple Hammond box.

Will stop here. Got to go listen to music! (And make amends to my wife!)

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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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