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Ouroboros 30th April 2004 01:02 PM

Richard Allan speakers. T-S parameters attached.
2 Attachment(s)
T-S parameters of many of the old, but well-respected Richard Allan drive units.

Data just received from RA themselves.

Jonathan Bright 1st May 2004 06:24 AM

Dear Ouroboros, Thanks, very thoughtful. I own an HP12B 1979 vintage (not sure which Res. Fq. yet) It is going in a sub one day. I needed those specs. Jonathan Bright.

quasi 23rd September 2005 12:41 PM

Richard Allan Atlas 15
Hi Ouroboros

I have been given a Richard Allan Atlas 15 so your specs are really useful. Do you have any information about it's power handling?


AndrewT 23rd September 2005 04:13 PM

I had a R.A. Pavane way back in '71/2. It was a 3way with a power handling for the whole including crossover of 25w from memory.
The CG12 in there would I guess handle about 15w (or maybe it was 12.5w) but it was very efficient. When replaced with Tannoy HPD385 (94db/w) in 100litre cabs the Pavane needed less voltage than the Tannoy for the same volume.
In those days manufacturers had only just started going down the route of using power to replace air inside the cabinet. Only recently have they started re-inventing the wheel to get impact and livelyness back into speakers.

googlyone 20th January 2008 08:30 AM

OK, this is a few years out of date, but I guess it is worth adding a snippet ehre...

The Richard Allan ATLAS speakers were quite high power for their time. The ATLAS-15 was the big brother of the HD-15. The HD-15 was 125Watts "RMS". The HD-15 used a 2 inch voice coil, and with music driven at these levels is a reliable driver.

The appilcation of the HD and ATLAS series was for PA use, though these drivers are of excellent quality, and more than applicable for hifi use. They have a surprisingly flat frequency response and low distortion even to fairly high levels.

John Cory 18th May 2013 05:38 PM

Hi There.
Anyone out there have any idea what the data / Thiele-Smalls are for a Richard Allan CG12 TC? I've "inherited" a pair and I'd like to build suitable cabs for them.
The Sound Man

googlyone 25th May 2013 05:16 AM

I used to have a pair of Richard Allan CG-12 drivers. I would imagine they will be very similar to the one with the whizzer.

Fs: 32Hz
Vas: 257 Litres
Qt: 0.425
Qm: 10.1
Qe: 0.44
Le: 0.53mH
Re: 7.46 Ohms
Sd: 490 cm2

These were best in a fairly decent sized vented enclosure. They were absolutely excellent drivers, and had a very well behaved frequency response.


John Cory 26th May 2013 06:51 PM

Thanks Googlyone.
Plugged the data into my faithful design program and hey presto! a 250 litre box appears. bloody big?? Anyone know where I can get plywood cheap?
The Sound Man
Anyone know the upper frequency limit of this speaker?

googlyone 30th May 2013 09:35 PM

You will be able to get away with a much smaller box than that - but dont expect a petite little 20 litre box - these are honest to god fold fashioned drivers... Big vented boxes a go-go.

I reckon those drivers used to be in a box of about 150litres or so - they were big but not crazy. I do not have the actual box dimensions as rather unusually for myself I reused the original boxes.

I do recommend that you measure the T&S parameters yourself. Tricks to this are:
- Measure Re as accurately as you can - the remaining parameters are very sensitive to errors in this
- If you have a sound card based measurement system, use Audua using the aded mass method, or
- If you dont have a sound card measurement system, use an oscillator, multimeter and closed box method. There are online tools that will walk you through this.

One thing that your model should have shown is that you can expect some surprisingly good low end performance from the drivers.

On measuring their frequency response I also found that their response out to quite a high frequency (kilohertz region) was very good indeed.

Have fun!

radiosmuck 31st May 2013 01:36 AM


Originally Posted by John Cory (
Hi There.
Anyone out there have any idea what the data / Thiele-Smalls are for a Richard Allan CG12 TC? I've "inherited" a pair and I'd like to build suitable cabs for them.
The Sound Man

I can get you the internal measurements of a box that contained a Richard Allen CG-12, could be a Parvane.

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