SpeakerTalk

pjaj · Posted: Sun Jan 18, 2004 7:12 pm Post subject: HiFi News 1974 design

Does anyone remember a fairly massive design published in HiFi News in 1974 (April?) which used a B139, B110, T27 and a Coles supertweeter? It was two infinite baffel (sealed boxes) in one box about 4ft high, 1 ft wide and some 18 inches deep and lined with cement rendering.
I built a pair of these at the time, but she-who-must-be-obeyed "suggested" I sell them when we moved house about 15 years ago Crying or Very sad

.
I think I still have the article somewhere, if anyone is interested I will try to look it out and scan it in.
They were magnificent with organ music, and when a friend bought his new Quad "brick" (404?) round it was the Quad that started to smoke Shocked

before the speakers showed any distress.
I have just bought a pair of B139s on eBay (£84+P&P) and will probably make myself a "coffin" from them.

terry · Posted: Sun Jan 18, 2004 11:42 pm Post subject:

I would be very interested in seeing the article. I remember the HiFi Answers Transmission Line Design which used a B139, B110, T27 and the Coles Super Tweeter. Of course a number of such designs were about at that time.
Terry

pjaj · Posted: Tue Jan 20, 2004 1:10 am Post subject:

I've done a preliminary search, but I can't put my hands on it for the moment. I'm sure it's in a safe place - somewhere.
However I did come across the following clipped articles:

"The Basset" by Trevor Attwell Parts 1-3 HFN&RR June-August 1978. A sort of folded horn design sub woofer which used 4 off Elac Type 8NC/185. BUT the article states that you could substitute B139s (pair?) to get more power.

"High quality book-shelf speaker" by J.H.Wilkinson Wireless World October 1977. An infinite baffel design using B200 + T15

"A Hexagon Double-bass" by E.J.Jordan HFN&RR April 1979 using an array of his own companies 50 & 100mm units.

"A 'mini-line' Transmission Line" by P.Atkinson HFN&RR November 1978. A small transmissin line design using a B110 and an Isophon KK8. Interesting as it could be by the same author as my 1974 design and has the same proportions, but about half the size. quote "The mini-line and the maxi-line side by side. The latter is almost identical dimensions to the State of the Art but totally differnt internals." I'm pretty sure that the 1974 design was "The state of the art".

A 4 part article "A versatile Active Crossover" by Ben Duncan. HFN&RR Feb - May 1981.

"A simple, effective Crossover Network" by C.J.Brain. HFN&RR 1980

If any of these are of interest I could try to get them coppied or scanned.[/list]

jnash · Posted: Mon Mar 08, 2004 7:30 pm Post subject:

Not sure I know the date, but I have a Hi-Fi Answers reprint of a transmission line monitor based on the specs you describe by CJ Rogers.
I can mail a copy to you if you would like it.
The speakers I have are very similair to this design and sold by a company called "Badger"? something?? and advertized in the back of the UK mags back in the late eighties. Now thats a reprent I'm searching for!
Let me know if you are interested in buying my speakers. They are in perfect working order and recently overhauled.
I now live in Texas!

(Yes, her in doors is begging me to release them!)

terry · Posted: Mon Mar 08, 2004 8:22 pm Post subject:

terry · Posted: Mon Mar 08, 2004 8:24 pm Post subject:

jnash · Posted: Mon Mar 08, 2004 9:50 pm Post subject:

Ok Terry,
I just emailed you two scanned pics of the Hi-Fi Answers design.
Hope it works out.
Jim

terry · Posted: Mon Mar 08, 2004 9:54 pm Post subject:

pjaj · Posted: Mon Mar 08, 2004 10:32 pm Post subject:

terry,

Since there are quite a lot of pages involved, and I only have 56K modem connection, I have suggested that I send scanned images of the articles on a CD to the web site and they could be put up there for anyone who wants to download them. Watch this space.

Peter.

terry · Posted: Mon Mar 08, 2004 10:52 pm Post subject:

clive · Introductory Contributor Joined: 05 May 2004 Posts: 3

I have aquired a set of AMW Acoustic labs speakers with model no. A440 serial no. 1046L they seem similar to the item under discussion, they use the kef b139 [1044sp] ; b110 [sp1003]; a danish peerless 1" paper tweeter [no details looking very sad] and 20mm dome tweeter with made in england no details. They are also using a handmade crossover and handwound inductors in the crossover [all spray painted black so values are unviewable] . They sound flat and tweeterless the kef drivers are dated 1975. I guess the first thing to try is new tweeters any suggestions appreciated. I did have to drill and jigsaw the rear of 1 unit to get access and the boxes while still stong and repairable has baddly chipped exterior venner. The boxe measures internally 700mm height ; 385mm wide and 240mm deep a gross volume of 64 liters less 190mm [10mm wall ] cardboard tube for mid range 7 liters] also less crossover and bracing for net say 55 liters . Less than ideal for bass units from reading should I remove cardboard tube or bit the bullet and build a bigger box?
Any help appreciated Idea

pjaj · Posted: Wed May 05, 2004 10:49 am Post subject:

Well Clive, from your description, the rechnical term for your speakers in their current condition is "b*gg*r*d". On the bright side, you already have two of the most expensive bits of sa speaker. IMHO you should cut your losses and start anew. There are many designs that use the B139 and B110 together with new tweeters. As has been said in other posts to this forum, Falcon, http://www.falcon-acoustics.co.uk/ , is a good place to start. Depending on your woodworking skills, you could either start from scratch or buy a kit with ready cut panels.

clive · Introductory Contributor Joined: 05 May 2004 Posts: 3

Thanks pjaj for link and terry for providing this forum Smile

terry · Posted: Thu May 06, 2004 7:01 pm Post subject:

Clive
Probably the simplest design could be based on the KefKit3. But as said above you have the basic elements to make a range of speakers.
Terry

clive · Introductory Contributor Joined: 05 May 2004 Posts: 3

Thanks Terry, The kefkit 3 is probably the simplest way with known results I was going to try Vifa D26 as tweeters and measure the existing crossover to see if any problems , if so it's probably capacitors which are easily replaced. I am tempted by the fiddler inside, to do what I wanted to do in the 80s but was a poor student, and had no money. Which was a 400 / 600mm or so diameter steel reoed concrete pipe cut to length for ideal volume 20mm ply wood ends and lay as coffin on spikes with upholstery padding on top of pipe and upholserty material velcoed [ to adjust for my poor sewing] around all but ends. Probably do one and compare to thebest current box with new tweeter and cross over checked. Any comments appreciated.
Clive