Richard Allan HP 12B

[ClaudioB]

Hello,

Recently, a good friend gave me two woofer 12 inches "Richard Allan Super HP 12B 8 ohms", never used! still in the box!
(He gave me also two "Decca London Ribbon Tweeter"...... In their boxes too.....)

The 12B wont stay in their boxes for a long time. I focus on them but I can not find the thiele-small parameters, bandwidth curve ect and to pay tribute to those speakers those informations are indispensables.

Your help will be very appreciated

Thank you

[tinitus]

Lucky you

Richard Allan made very nice drivers, and new in boxes!!...are those 12" with coated paper cone, red surround and gold chassis or the later ordinary poly ones

Be carefull with the Decca ribbons, they are fragile and should be handled with care, should be crossed rather highish so you will need a wideband midrange...I believe they are quite rare now a days so please dont "burn" them, they are not very happy playing too loud...but if you dont feel like using them you should be able to get a good price...but I have no clew how much

Richard Allan was my first real highend speaker would really like to see some pictures, if possible

[Ouroboros]

According to data I received a couple of years ago from RA, the HP12B Super came in two versions, a low-resonance model and a high resonance model. The data is attached.

[Ouroboros]

I bought a couple of the ordinary HP12B drivers last year (not the -Super version), but I've not yet measured their TS parameters to see how they match the data in the table.

I use their excellent HP8B units, two in 34 litre sealed boxes, and another two in 62 litre transmission-line enclosures. Both work extremely well.

I have measured the HP8B TS parameters, (though I don't have them at hand), and the Fs was very different from the published data. I remember that I measured an average of 33Hz across four units, compared with the published 24Hz. I really ought to re-check the units in the sealed box speakers, as these are the ones I use every day, and see if regular use has dropped the Fs.

[Ouroboros]

Be a little wary of the data I showed earlier from RA, some of the CMS figures look a little suspect to me.

If I get the chance I'll measure the two HP12B units I have this weekend. If I do I'll show the data here.

[ClaudioB]

Thank you both of you, Tinitus & Ouroboros for your interest in my project. Ouroboros, if you have an opportunity to conform me the data, it will be very appreciated. One of my default but also a quality: I vest 200% of my self in a project (whatever the project) when I know what I do.

Thank You again


I add fews pictures of my treasure.

[ClaudioB]

In my last post I did a mistake with the attached jpg.

[tinitus]

Nice, thankyou

I love that label...I remember that RichardAllan drivers had a peculiar smell, kind of tarr like...if its the coating or the glue I dont know
I have only seen the 12" with harmonium surround(yellow?)...is it rubber or foam ?

[Ouroboros]

All the RA drivers I have (HP8B, LP8B and HP12B) have high-quality rubber roll surrpounds that don't seem to deteriote much with age. The red felt outer ring is simply a mounting gasket if you want to mount the unit to the rear of a baffle board.

[planet10]

Originally posted by ClaudioB
"Richard Allan Super HP 12B 8 ohms"
"Decca London Ribbon Tweeter"

I figure the Deccas are the score in that batch

Typically (at least over here) XOed at 1.6kHz 3rd order.

I got the opportunity to tweak out a set of prototype standmount Decca speakers -- 8" plus the Ribbon XOed at ~1k. (a wonderful all night listening session insued (NAIM 250/LP12))

Th eribbons are delicate, but exchanges can be had from Howard Dawson (link to a piece on XOs).

http://hd-audio.orpheusweb.co.uk/maxlife.html

Now if you'd like to sell them cheap...

dave