Goodmans Triaxioms

[istari_knight]

I bought what is apparently a NOS pair of "212c" Triaxioms last night. Anyone familiar with them ? I've enjoyed some axiom 301's in the past so when I saw these going cheap it was difficult to resist...

http://i26.photobucket.com/albums/c129/istari_knight9/_57_zps07623631.jpg

Should be good for a laugh on the end of my little EL84 amp anyway :D

[Reffc]

Really good vintage speakers there James, a cracking find. 3 speakers in 1 with a claimed frequency response of 20Hz to 20KHz when mounted in bass reflex cabinets of the appropriate size. (the driver has a self resonance of 35Hz)

The only thing you need to watch is amplification. They are nominally 15 Ohm speakers of high sensitivity and lowish power handling (30W from memory) so possibly best with an appropriate valve amp?

Have you got the crossovers too? Difficult to find the circuit for these now.

They need large cabinets, Circa 4.5 cubic feet or 127 litres net. Something around the 1m tall by 420mm wide by 350 would do the trick (external dims).

[walpurgis]

Wow! You'll enjoy those James. Amazing condition and very collectable. Need a big box though.

[istari_knight]

Thats exactly what I wanted to hear chaps ! I'd never seen a pair before but the second I clapped eyes on them I knew they weren't the usual dross :eyebrows:

Paul, I'm playing with a little 12wpc EL84 amp at the moment so no worries on that front. Whilst searching for information I stumbled across a few pictures which revealed the crossover is contained within those cylinders on the fly leads, each contains a waxy looking inductor, a film cap and what appears to be a rheostat pot.

Big cabinets will be alright, my work in progress listening room is a decent size & will be for my entertainment only [converted 18x12 summerhouse] I probably won't be doing anything with them until thats completed but what sort of cabinets do we think might work best ? There's such little info out there... Would a large cab designed for 12" DC's work ?

[Reffc]

Thats exactly what I wanted to hear chaps ! I'd never seen a pair before but the second I clapped eyes on them I knew they weren't the usual dross :eyebrows:

Paul, I'm playing with a little 12wpc EL84 amp at the moment so no worries on that front. Whilst searching for information I stumbled across a few pictures which revealed the crossover is contained within those cylinders on the fly leads, each contains a waxy looking inductor, a film cap and what appears to be a rheostat pot.

Big cabinets will be alright, my work in progress listening room is a decent size & will be for my entertainment only [converted 18x12 summerhouse] I probably won't be doing anything with them until thats completed but what sort of cabinets do we think might work best ? There's such little info out there... Would a large cab designed for 12" DC's work ?

I think that they would be best with vented or ported cabinets James. You can work out the rough port dimensions running a sim on the recommended box size and tuning the port appropriately. To get the correct tuning a few things are usually needed such as the Qts of your speaker bass driver and its Vas. However, these were made before the Thiele-Small parameters came into being so you may need to play a little with tuning. I'd start by using a couple of 100mm cardboard tubes at around 150 to 200mm long and try different lengths until you get the best response. You can calculate it more accurately by building a small sealed test enclosure (say 30 litres) which is used to them work out Vas and Qts for a better approximation of the port. You could also run with a variable slot (vented) arrangement and play around with that. Otherwise it's a case of doing some in depth research on these.

[Reffc]

OK...a little research has thrown up that the 212c drivers had a "Q" of closer to 0.7, so they'll work well in bass reflex, sealed or even open baffle configurations. I've found these cabs for the Goodmans 12 inch drivers so perhaps somewhere to start?


http://i215.photobucket.com/albums/cc317/Mamimili/OB/P6.jpg

[Ali Tait]

I have a set of Axiom 401, must give them a go sometime, they've been stored away for years.

[Macca]

'For amplifiers up to 15 watts (30 watts in U.S.A)'

What's that all about? 1 Brtish watt = 0.5 American watts? I've never heard that before.

[istari_knight]

I think that they would be best with vented or ported cabinets James. You can work out the rough port dimensions running a sim on the recommended box size and tuning the port appropriately. To get the correct tuning a few things are usually needed such as the Qts of your speaker bass driver and its Vas. However, these were made before the Thiele-Small parameters came into being so you may need to play a little with tuning. I'd start by using a couple of 100mm cardboard tubes at around 150 to 200mm long and try different lengths until you get the best response. You can calculate it more accurately by building a small sealed test enclosure (say 30 litres) which is used to them work out Vas and Qts for a better approximation of the port. You could also run with a variable slot (vented) arrangement and play around with that. Otherwise it's a case of doing some in depth research on these.

Thanks for the info Paul, I used my old 201's on an open baffle like this: http://jelabsarch.blogspot.co.uk/2012/06/open-baffle.html

Sounded great but were A) fugly, and B) difficult to position so I'm not in a hurry to replicate that... A proper cabinet is definitely the way forward. Looks like It'll take some trial & error.

[istari_knight]

'For amplifiers up to 15 watts (30 watts in U.S.A)'

What's that all about? 1 Brtish watt = 0.5 American watts? I've never heard that before.

It is odd but Goodmans printed the same on every driver :scratch:

An American forum member said the following on the subject: "The difference in rating is simply that of the difference between RMS rating and IHF rating. The Institute of High Fidelity (an American organization) measured power from positive peak to negative peak, which increases the apparent power."

Seems legit ?

[Macca]

There you go then just the Yanks talking it up again.

Thye do look like intersting drivers though. Just a thought if you are converting a wooden summer house you could mount the drivers into the walls with the cabinets outside. I'm envisioning a summer house with two sizeable sheds adjacent to it...the sheds being the cabs.

[Firebottle]

'For amplifiers up to 15 watts (30 watts in U.S.A)'

What's that all about? 1 Brtish watt = 0.5 American watts? I've never heard that before.

I hate to say it Martin but you are too young.
A while ago there was always the disparity of American versus British watts, British was always rms (appropriately regarding quality gear), whereas the American was always 'peak' power which is twice the figure.

:cool: Alan

[istari_knight]

There you go then just the Yanks talking it up again.

Thye do look like intersting drivers though. Just a thought if you are converting a wooden summer house you could mount the drivers into the walls with the cabinets outside. I'm envisioning a summer house with two sizeable sheds adjacent to it...the sheds being the cabs.

You've just blown my mind Martin... Thats one hell of an idea ! :respect:

[Macca]

Since I live in a terrace I've often thought of doing a similar thing. The party wll with one neighbour is only one brick thick so I could remove a few and mount drivers in the wall, using her house as the cab. I've not asked her if she would be amenable yet and I doubt she would be but hey nothing ventured nothing gained...I could always do it when she is away and present it as a fait accompli :)

[BTH K10A]

OK...a little research has thrown up that the 212c drivers had a "Q" of closer to 0.7, so they'll work well in bass reflex, sealed or even open baffle configurations. I've found these cabs for the Goodmans 12 inch drivers so perhaps somewhere to start?


http://i215.photobucket.com/albums/cc317/Mamimili/OB/P6.jpg



The Triaxiom works very well with the Goodmans ARU as specified in the above drawings.

Not easy to come by pairs nowadays but they do turn up

www.ebay.co.uk/itm/One-GOODMANS-ARU-speaker-port-Acoustical-Resistance-Unit-264572-Axiom-Audiom/151381528620?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%2 6asc%3D24435%26meid%3Dce80b85a091a4f9f831d5044424e 614d%26pid%3D100011%26prg%3D9173%26rk%3D1%26rkt%3D 10%26sd%3D250851235168

Or you could try making some yourself

[istari_knight]

I looked into ARU's when I had the Axiom 301's... They look fairly easy to reproduce, I have all the dimensions & material thickness measurements on file. One chap on Diyaudio recalled building cabs for them as a young man, apparently the budget alternative to the ARU was to staple a couple of hankie's over the port opening :D

Found this too:

http://i26.photobucket.com/albums/c129/istari_knight9/Triaxiom_zps80e95a35.jpg

[walpurgis]

You suggested using Tannoy cabinets. It would certainly be a cheap way out. There are plenty of Cheviot boxes about and they could be suitable, as they are more rigid and better braced than most of their 12" driver cabinets. They'll give the drivers a reasonable amount of 'breathing space' and probably come with enough suitable damping material. You'd have to blank the front hole left by the tweeter adjuster and adapt the terminal panel hole on the back, but it would all be easy. Experimenting with port dimensions may be of benefit, but it could be that the standard port suits the Goodmans units.

[jaym481]

The boxes in those drawings are aperiodic ported, and require the ARUs. If you want standard ported boxes you need to go larger. I wouldn't go with Cheviot cabs if you go with Tannoys, though you could probably cut up the baffle and make it aperiodic, which should work. I think Cheviots are about 70L.

I have two pairs of 201s, a pair of ARUs and a few Trebax tweeters. The coax tweeter of the Triaxiom is the same as the Trebax, though mine are the newer models with the round horns. If you need any dimensions or info on the ARU just ask, I can take measurements for you. The "cloth" appears to be thin red felt, with a metal mesh inside the wooden frame. Looks simple to reproduce.

[istari_knight]

Thanks for the offer Jay but I think I've got all the necessary info to replicate some A.R.U's but will give you a shout if I get stuck.

Unfortunately Cheviot cabinets do look a little on the small side but there's plenty out there so I'll just have to keep an eye out... Interestingly Goodmans also produced plans for a "non A.R.U" cabinet which is rather on the large side...

http://i26.photobucket.com/albums/c129/istari_knight9/Goodmans_zps1fca706b.jpg

[ff1d1l]

I've heard these work rather well in a Tannoy GRF cab.

[walpurgis]

If anybody's interested, there's a lovely looking pair of Triaxioms on eBay at the moment. Finishing today and silly cheap at the moment (£56). I'll be expecting the bids to rocket to around £350 in about six and a half hours, when it finishes.

http://www.ebay.co.uk/itm/Pair-Of-Goodmans-Triaxiom-212c-12-3-Way-Full-Range-Drivers-15Ohms-/221539233552?pt=UK_AudioVideoElectronics_HomeAudio HiFi_HiFiSpeakers&hash=item3394c46f10

[istari_knight]

They're mine :) I tried them in a 70L cabs [less than ideal, I know] but good enough to get a jist of what they do/don't do & unfortunately, lovely as they look the sound just isn't for me. Awesome for jazz/blues but play anything with balls & you can forget about it.

As you can see they reached a measly auction price & the buyers Russian :bog:

I'll be listing them in the classifieds shortly methinks.

[walpurgis]

Ah. So you won't be sending them to Russia. Wise move!

It's not unheard of for valuable items to go overseas and disappear and then have the buyer reverse the PayPal payment, leaving you truly bolloxed.

I don't ship abroad.

[Ali Tait]

I suppose you could if you stipulated that the buyer arranges shipping, that way the responsibility lies with the buyer.

[walpurgis]

I suppose you could if you stipulated that the buyer arranges shipping, that way the responsibility lies with the buyer.

Doesn't stop the payment being reversed though.

[istari_knight]

I don't mind sending abroad, in fact overall I reckon I've had less problem buyers from overseas than the UK. Problem is, on the one or two occasions things have gone Pete Tong its always been Russia or Italy.

[EddieT]

Hi guys
Look I’m new here but I have two pair of Goodmans 212c. One pair are in the original Sherwood cabs with ARU baffles but lacking the two innner curtains to improve base and the other are being restored to go into front loaded horn cabinets. I really cannot understand what the op is on about. He seemed to ask a lot of questions only to say that he was selling his on eBay. I gotta correct some things here. I use mine with a Leak Stereo 20 valve amp and Point One Stereo preamp and they play all kinds of analogue material very well, including music by The Stones, Zepplin, Chilli Peppers, Weather Report etc. I’ve had 110dbl at 6ft (about as much as my little room can take) and it was all there. I’ve also played acoustic 12 string guitar (Kottke) and jazz records recently for the state president of an HiFi club (sorry I’m not up on that stuff and didn’t know he was one until he told me) and he listened to one album after another so something is right!

The real reason I’ve bothering with this (really it’s awesome when ppl dis great vintage gear keeping prices down) is that someone posted that they have the schematics and I’m trying to find out what type of caps were used in the crossovers, so if that guy can help, and I know it’s been a while, please I’d really appreciate it,
Be Cool
EddieT

[walpurgis]

You might get lucky, but this thread has been inactive for over four years.