Cabinets for Full Range Goodmans Axiom 201

[landrupp]

Hello everyone

this is my first post on this forum, sorry for my english, i'm not a native speaker and i will help me with google translate.
I have a couple of Goodmans Axiom 201 fullrange and I want to build a cabinet for them, some time ago I found this project on TnT-Audio:
[DIY project] DIY Tannoy 12" Dual Concentric Horn
[DIY project] DIY 12" Goodmans Axiom 201 Horns
therefore, the author of the article took an old Coral cabinet project for Beta 10 speakers, modified some measures and tried to mount two types of speakers, one of which is my Axiom (in the 2nd part of the article).
however, I have some doubts about how to make the construction (materials, dimensions and verification of the horn) and I was wondering if anyone on this platform has had experience with this project.
For example, without listing all my doubts but only a few:
- instead of MDF I would use 25mm birch plywood: is it okay?
- the thickness of the internal panels of the Horn must be considered to dimension the depth of the cabinet?
- in the cabinet designed for the Coral Beta 10 there is little space for the Axiom speaker, do you need to tilt the horn panels to mount the axioms or do you have to change the length of the panels, then change the length of the horn?
...
alternatively, does anyone know of any other projects for my Axiom 201? I searched a lot but found nothing ...

Thank you for your attention.

Landrupp

 

[Galu]

alternatively, does anyone know of any other projects for my Axiom 201?

Welcome to the forum Landrupp!

In case you haven't come across them, I've given a link to the original Goodmans enclosure designs.

http://ukhhsoc.torrens.org/makers/Goodmans/1969_Catalogue/Page20.gif

The lower design is a bass reflex, the upper design employs an ARU (Acoustic Resistance Unit) for aperiodic loading.

Perhaps not what you are looking for, but may be of historical interest.

 

[planet10]

And here one i did:

Both of those horns, i would strongly suspect, are far from optimal. Too small to start with.

Galu, your link could well be one of the pages i sccanned from an original brochure.

dave

dave

 

[Galu]

Galu, your link could well be one of the pages i scanned from an original brochure.

I obtained it from the 'UK Hi-Fi History Society' website, ukhhsoc - audio documents, a valuable resource of historical UK audio documents.

 

[planet10]

I have scatterd my scans all over, and the originals were up for grabs.

But you made me go look. That is a different page.

http://p10hifi.net/forum/goodmans-axiom-brochure.pdf

The 4th page of this has some more (if they are not the same). Cabine design has come some way since then.

dave

 

[Galu]

Cabine design has come some way since then.

But dontcha just love those old brochures!

 

[planet10]

:^)

That was from my eBay days. A pile of “scrap” paper that paid some bills.

dave

 

[GM]

however, I have some doubts about how to make the construction (materials, dimensions and verification of the horn) and I was wondering if anyone on this platform has had experience with this project.
For example, without listing all my doubts but only a few:
- instead of MDF I would use 25mm birch plywood: is it okay?
- the thickness of the internal panels of the Horn must be considered to dimension the depth of the cabinet?
- in the cabinet designed for the Coral Beta 10 there is little space for the Axiom speaker, do you need to tilt the horn panels to mount the axioms or do you have to change the length of the panels, then change the length of the horn?

Greets!

You can and yes, you should adjust the internal dimensions as required.

Please post your other horn questions on this old thread and/or PM Peder since he's built some:

https://www.diyaudio.com/forums/full-range/316609-coral-beta-12-a.html"]Coral Beta 12

Good luck and if you do get what you need, please document/post sufficient details here in case others in the future are interested.

GM

edit: Just looked at the TNT article; isn't this what you're wanting?

[DIY project] DIY Tannoy 12" Dual Concentric Horn

https://www.tnt-audio.com/jpg/cabinet.jpg

 

[landrupp]

Welcome to the forum Landrupp!

Perhaps not what you are looking for, but may be of historical interest.

Hi Galu

thanks for the reply ... I had seen those projects, I had found them at this address where a original PDF Goodmans brochure is downloadable which includes at the end 3 projects for the axioms and others:

https://goodmans.zendesk.com/hc/en-.../204457669/Goodmans-Axiom-Audiom-brochure.pdf

but I remain skeptical because of the use of some "curtains" (in double arrangement they give the A.R.U.) which - if I have not misunderstood - were produced by Goodmans and are currently difficult to find ... they could be these:

a.r.u. panels goodmans - Google Search

I understand that they are not manufactured in diy, but they are industrially produced elements ... moreover, they seem a little too complicated, I would not know exactly what sound I would get in the end and I was looking for something really simpler to start my diy, but if someone built those Goodmans cabinets maybe he could tell us about his experience here, he would be listened with interest.

Basically, what I'm looking for is to improve the sense of 3D reality of my sound, I seem to understand that the TNT-audio project has in this an interesting strength and a constructive simplicity that I like.

 

[landrupp]

And here one i did:



Both of those horns, i would strongly suspect, are far from optimal. Too small to start with.

dave[/QUOTE]


hi Planet10

I had also seen your works with the axiom's, congratulations I really like, I'm sorry that your opinion is doubtful about their sound (I seem to remember that you were not entirely satisfied with the slightly slow and soft bass .. .)

but thanks for your answers, maybe your old Goodmans brochures are turning the web apparently ...
;)

 

[landrupp]

Greets!

You can and yes, you should adjust the internal dimensions as required.
...
Good luck and if you do get what you need, please document/post sufficient details here in case others in the future are interested.

GM

edit: Just looked at the TNT article; isn't this what you're wanting?
]

hi GM

thanks for the report, I did not know that discussion ... I will try to ask news directly to those who have already built that project ...
Yes, the link of the article you published is exactly the project that interests me

 

[freddi]

I could not read the dims easily on that one drawing so attempted to make it a bit easier.

With hornresp, such a cabinet can be scaled uo or down

 

[freddi]

fwiw - here's approximately what one 301 spec might do in the old JBL "Harkness" blh cabinet

plans for a version with curved reflector
https://3.bp.blogspot.com/-iMbawTx7...mjfNRWDnYW2oYh8zKPip2gCLcBGAs/s1600/har2.jpeg

 

[planet10]

.. the A.R.U.) …

Really an early crude implementation.

There are many ways to build your own. The Dyna A25 is a good example. Fiberglass insulation sandwhiched between 2 pieves of gutter mesh.

But i prefer either a heavily damped TL, or a whack of holes on the back, heavily (and carefully) damped on the inside of the box.

dave

 

[planet10]

hi Planet10

I had also seen your works with the axiom's, congratulations I really like, I'm sorry that your opinion is doubtful about their sound (I seem to remember that you were not entirely satisfied with the slightly slow and soft bass .. .)

Not my build, i designed it for someone else, i have seen an A201, niot heard them so i have no opinion..

dave

 

[landrupp]

Not my build, i designed it for someone else, i have seen an A201, niot heard them so i have no opinion..

dave

.
excuse me Dave
I had read a post on those speakers of the photo a long time ago and perhaps my memories (and my English ...) have deceived me, I remembered badly evidently ...

 

[landrupp]

I could not read the dims easily on that one drawing so attempted to make it a bit easier.

With hornresp, such a cabinet can be scaled uo or down

hello Freddi
in fact I also had difficulty reading the measurements of that project, the photo is not very clear ... I redesigned the entire Coral project with autocad starting from the images found on the web and in the Tnt-audio article and the measurements are the ones you showed too.
Then I tried to redesign the cabinet modified by the author of the article with autocad to insert the axion 201 starting from this image of tnt-audio:

but unfortunately the measurements are never right with respect to the image, in the sense that while using the measurements declared in the article (1140mm in height x 470mm in width x 450mm in depth, using 32mm MDF panels), it turns out that the image of the modified project is not coherent, that is, it was not drawn in scale and only has the value of an illustrative scheme, in fact if you scale the image to adjust the depth to 450mm the corresponding height is 900mm and vice versa ... in short, the the design is not proportionate, so it is not clear "if and how" the measures of the internal panels of the horn have been modified to accommodate the Goodmans speakers.
In principle, is it possible to think that the group of internal panels has been tilted backwards and lowered to make room for the Goodmans? Doesn't this change the length of the horn?
In the image that I publish below, I drew the section of the Coral horn in red and increased it in height by 200mm as required in the tnt-audio article, then I inserted on it (in blue color) the size of the Goodmans Aion 201 ... as it is possible to see, without modifying anything of the internal panels, it is not possible to mount the speaker inside them: there is not enough space and - moreover - the diameter of the axiom is 312mm while the height of the front baffle is 315mmm (!) ...

if I look at the photos of the article, I realize that the baffle covers the internal inclined panels and the speaker has been mounted lower ... other changes of which there they aren't measures or explanations: I am not such an expert DIYers and this project - for now - is beyond my ability.

 

[landrupp]

Today I tried to change the dimensions of the cabinet so as to insert the Axiom 201 without intervening on the wooden panels by digging or shaping them to seal their edges around the driver magnet, as recommended in the text of the TNT-audio article.
I do not know if this modification that I designed could have negative effects on the speaker performance, a more expert opinion would be welcome, but the internal development of the horn is maintained and what changes is only the size of the room in which the speaker is mounted. 'speak and the length and inclination of the slide towards the floor, so that the whole cabinet is 70mm deeper (from 410mm to 480mm), while width (410mm) and height (1020mm) would remain unchanged.

Are changes able to change or distort the sound of the TNT-audio project?

 

[planet10]

Hard to get excited about these warmed over 3 decade old BK-201 like horns.

dave

 

[landrupp]

Hard to get excited about these warmed over 3 decade old BK-201 like horns.

dave

do you have a good advice to give me? I really like those cabinets anyway ...