View Full Version : Westminster 12" fronthorn DIY ...
Good evening,
I am glad that I am allowed to visit this forum.
At first ... I apologize for my grammar mistakes and wordplays (... i favor german lyrics).
I am living in northern germany.
Today I am looking for a plan of the westminster 12" fronthorn (diy).
I would like to modify my Tannoy DMT12 for 'lowmidtohighs' ... ( add with a fronthorn ... in combination with a BR 12"or15" for bass ).
Did someone has special knowledge and experience in the field.
Kind regards
(... just moved from 'welcome' to 'blank canvas'.)
Welcome Mic
Your DMT drive units were designed to work efficiently with ported enclosures and not really intended for use in front horn loaded designs. Also, the Westminster cabinet design was intended for 15 inch drive units. It will work using 15 inch HPD drive units or some of the later K series (as actually used for the Westy). It is not a good idea to partner this with a separate driver for bass. You will struggle to get them phase matched and the crossover would be very complex, not just because of the phasing issues, but also because you'd be trying to match a front horn loaded efficiency with a bass unit into the same cabinet, which just wouldn't work very well, and it would also affect the loading of the main horn drive unit....a very very messy design which just wouldn't work properly imho. You'd also have to waste the efficiency gained from the horn loading to pad it down to match the output of the 2nd drive unit. No doubt some DIY enthusiasts have tried it and proclaimed their fondness for it, but it's not somewhere I'd chose to go with design personally speaking nor could I recommend it.
Rather than make life complicated fro yourself, you would be better using the appropriate 15 inch drive unit and proper Westminster build plans, if it is a Westminster that you have your heart set on. Having these custom built these days is not cheap. The cabinets alone would set you back well over £10K, but they do make for an interesting and challenging DIY project.
Hi Reffc,
thank you very much for your assessment.
I agree with you ... but I think a special xover were able to compensate phasing and spl.
Naturally the DMT will work in his own enclosure ... above the bass unit.
With all due respect ... IMO everyone eat his own cakes and would like them more if other people like these cakes too.
So I will do my best to try and find acceptable solutions - that is science ... it is diy.
As you mentioned, some diy enthusiasts have tried it and proclaimed their fondness for it ...
did you know someone who has special knowledge and experience in the field?
Hi Reffc,
thank you very much for your assessment.
I agree with you ... but I think a special xover were able to compensate phasing and spl.
Naturally the DMT will work in his own enclosure ... above the bass unit.
With all due respect ... IMO everyone eat his own cakes and would like them more if other people like these cakes too.
So I will do my best to try and find acceptable solutions - that is science ... it is diy.
As you mentioned, some diy enthusiasts have tried it and proclaimed their fondness for it ...
did you know someone who has special knowledge and experience in the field?
Errrr...yes?
@ Reffc:
Sorry ... I can't see what you mean ... never heard that phrase before.
@ Reffc:
Sorry ... I can't see what you mean ... never heard that phrase before.
You asked "...did you know someone who has special knowledge and experience in the field?"
To which the reply was "...yes".
I specialise in Tannoy DCs and loudspeaker design. I have given a fair assessment already and wouldn't chose or advise you to go the route you're suggesting for a number of good reasons based on sound loudspeaker design principles and knowledge, not on personal subjective opinion.
I can only offer advice though, not force people to take that advice. I have offered what I consider to be good advice to you without wishing to write a dissertation on loudspeaker design. Otherwise, I'd have to go into detail explaining things like how the Westminster cabinet works and why things like T&S parameters of the proper drive units needed for proper matching to that cabinet design matter, and also why using a separate woofer for that cabinet design is simply a bad idea. Honestly, that is a complex enough project for an experienced loudspeaker designer, let alone someone without the know how needed, so I was simply trying to save you time, money and grief by pointing you in the direction of just sticking to the Westminster design as intended if you want a challenging but rewarding project. As for the crossover design, that's a whole new can of worms if you did wish to press ahead with the design and I'm just not convinced that it would work well nor that you would be able to properly integrate the design without some major drawbacks and compromises to sound quality. Good luck with it though if you decide to press ahead.
Paul, thank you for your response.
You may rest assured that I have heard that message and I share your view.
However, I want to find a way to integrate my DMTs in my new larger living room (3500cubic feet).
Forgive me .. it is not easy for me to find the right words for my thoughts regarding my idea.
In short,
I am searching for a way to relieve the DMTs in the bass/lowmid response.
Thus the idea ...
add DMTs with a fronthorn ... in combination with a BR 12"or15" for bass.
I have experiences in loudpeaker design and I am looking for constructive suggestions ... and a Westminster construction plan.
Paul, thank you for your response.
You may rest assured that I have heard that message and I share your view.
However, I want to find a way to integrate my DMTs in my new larger living room (3500cubic feet).
Forgive me .. it is not easy for me to find the right words for my thoughts regarding my idea.
In short,
I am searching for a way to relieve the DMTs in the bass/lowmid response.
Thus the idea ...
add DMTs with a fronthorn ... in combination with a BR 12"or15" for bass.
I have experiences in loudpeaker design and I am looking for constructive suggestions ... and a Westminster construction plan.
You received constructive comments Mic, after asking for them from someone with experience & knowledge but clearly your mind is made up anyway. Sorry it's not what you wanted to hear. Good luck with the project :)
PaulStewart
31-12-2016, 08:57
Hi Mic,
There are people on this forum with closed minds who think they know best. I find it better to seek out those with a more open attitude. Speedy Steve of Magna Audio does a 12" Gold/HPD scaled GRF and is well versed in horn construction. Why not drop him a Personal Message and see if he can advise? He made some bits for the refurb of my Lockwood academies and I can vouch for the quality of his work.
Good evening,
I am glad that I am allowed to visit this forum.
At first ... I apologize for my grammar mistakes and wordplays (... i favor german lyrics).
I am living in northern germany.
Today I am looking for a plan of the westminster 12" fronthorn (diy).
I would like to modify my Tannoy DMT12 for 'lowmidtohighs' ... ( add with a fronthorn ... in combination with a BR 12"or15" for bass ).
Did someone has special knowledge and experience in the field.
Kind regards
(... just moved from 'welcome' to 'blank canvas'.)
Hi Mic,
There are people on this forum with closed minds who think they know best. I find it better to seek out those with a more open attitude. Speedy Steve of Magna Audio does a 12" Gold/HPD scaled GRF and is well versed in horn construction. Why not drop him a Personal Message and see if he can advise? He made some bits for the refurb of my Lockwood academies and I can vouch for the quality of his work.
And there are those who just think that they know it all, all the time. No one has all the answers but an honest answer was given with the reasons spelt out and there's nothing closed minded about that. I was trying to do the guy a favour FFS! If that's the direction he wants to go in, then he was wished "good luck" with it. I'm well versed in horn design too Paul, and contrary to your "closed mind" mantra, was pointing out the real pitfalls and challenges of such an arrangement. There's a damn good reason why such designs are not prevalent. Nuff said.
Sounds like the problem is that the DMT are sounding a bit lost in the large room, no doubt due to their curtailed bass response. Personally I'd save myself a lot of time and trouble and keep the DMT as they are and add two active subwoofers with DSP to fill in from 50 Hz down. Butchering the Tannoys to make some sort of Frankenstein horn/bass bin contraption sounds like it would be an expensive stab in the dark. Okay two proper sub won't be cheap but I guess you could build them yourself. And the DSP would give you maximum flexibility in tuning them to be just right.
@ Reffc ... thank you for your assessment.
Tolerance, respect towards those who those who think and act differently and the right to individuality are the core values ...
I am a dissident and my open mind feed my ego ... think and act, make your own experiences.
Thank you PaulStewart,
GRF ...
I had thought about that and stopped it because GRF has allegedly not enough bass (<60hz) for many people.
In the past, my own experiences has shown me, that backloadedhorns like GRF in similar size needs a special tuning for a special drive-unit (i.a. Q-factor) ... in short: Vd,Ah,Am,Xmax,k, upper/lower frequence limit 'versus' BL etc. ... in consideration of the position of the loudspeaker and acoustics in the room ... and so on.
Based on these experiences and other considerations, and taking into account the fact that I love a great variety of music style and
my listenig room is very special, I prefer to split the signal in bass+lowmidhighs ...
also to protect the DMT from powerful low frequency signals.
However, I'm curious about everything that happens (in life) ... and I'll visit SpeedySteve's site today.
Thank you for pointing that out.
Sounds like the problem is that the DMT are sounding a bit lost in the large room, no doubt due to their curtailed bass response. Personally I'd save myself a lot of time and trouble and keep the DMT as they are and add two active subwoofers with DSP to fill in from 50 Hz down. Butchering the Tannoys to make some sort of Frankenstein horn/bass bin contraption sounds like it would be an expensive stab in the dark. Okay two proper sub won't be cheap but I guess you could build them yourself. And the DSP would give you maximum flexibility in tuning them to be just right.
... exact.
Not sure if that means you like my suggestion or hate it.
Easy /direct suggestion :-) BUY a pair of 15" DMT 2's
Their twin 15's Will solve both your loudness and Bass concerns.
Easy /direct suggestion :-) BUY a pair of 15" DMT 2's
Their twin 15's Will solve both your loudness and Bass concerns.
Thank you ... but this is not what I want to do.
Sounds like the problem is that the DMT are sounding a bit lost in the large room, no doubt due to their curtailed bass response. Personally I'd save myself a lot of time and trouble and keep the DMT as they are and add two active subwoofers with DSP to fill in from 50 Hz down. Butchering the Tannoys to make some sort of Frankenstein horn/bass bin contraption sounds like it would be an expensive stab in the dark. Okay two proper sub won't be cheap but I guess you could build them yourself. And the DSP would give you maximum flexibility in tuning them to be just right.
@Macca: ... 'a bit lost in the large room' ... this is nearly the problem,
... and this what I want to do:
A 12" or 15" bass in BR for low freqency signals,
the 12"DMT's add with a fronthorn like the 15"Westminster ... (fronthorn Ah tuned to 12"Sd) - for lowmidhighs.
In short:
( ( ( ( Westminster 15" fronthorn/Ah, Am, Xmax, k _______ C O N V E R T _______ to a 12" fronthorn ) ) ) )
... with nearly the same lower frequence limit.
(Am stay the same > Ah convert from 15" to 12" > k in relation to Xmax.)
It would be helpfull an original Westminster blueprint (of this area) ... for reference purposes.
... or is there someone who would check the dimensions, please.
paulf-2007
02-01-2017, 23:01
To the OP, if a front horn is what you want then go for it, but please don't throw too much money at it. If you feel your room is too big and that's the reason for the front horn then the kind of front horn on the Westminster IMO won't give you the extra spl you need. But if you're set on it then I hope it works for you. If I had a large room I would use BMS compression drivers on a proper front horn and be done with it. I had BMS compression drivers on 200hz tractrix horns and liked them very much but active crossover problems destroying a ribbon convinced me to simplify my set up, but that's another story. Contact speedy Steve he started out with grf's and horns and then went all front horns.
anubisgrau
03-01-2017, 09:51
FWIW westminsters are anything but just a fronthorn. actually the least of their impact comes from that small and short waveguide.
To the OP, if a front horn is what you want then go for it, but please don't throw too much money at it. If you feel your room is too big and that's the reason for the front horn then the kind of front horn on the Westminster IMO won't give you the extra spl you need. But if you're set on it then I hope it works for you. If I had a large room I would use BMS compression drivers on a proper front horn and be done with it. I had BMS compression drivers on 200hz tractrix horns and liked them very much but active crossover problems destroying a ribbon convinced me to simplify my set up, but that's another story. Contact speedy Steve he started out with grf's and horns and then went all front horns.
@paulf-2007 ....
Thank you for your inspiration to walk the way with compression drivers.
I went this way in the 80s with Coral Drivers (alu-diaphagm) ... change to an identical model SAMMI sm-104 (phenolic!) ... to lowther c45 with horn ... and so on.
Since 10 years I lie in the harbour of contentment (... can it be said so in English ?) - with TANNOY.
Today I need a decent bundling of the natural DMT sound - I think this is the right way for me ... perhaps also for some other folks which are not happy with compression- drivers.
FWIW westminsters are anything but just a fronthorn. actually the least of their impact comes from that small and short waveguide.
Yes ... I think, the Westminster is a backloadedhorn ... with a little fronthorn ( short waveguide in other words).
paulf-2007
03-01-2017, 22:01
FWIW westminsters are anything but just a fronthorn. actually the least of their impact comes from that small and short waveguide.
My point Gordan, but maybe not articulated in my limited English
Horses to Water seemingly applies. unfortunately.
Recycling a pair of Dorky 12" DMT's into a twin Driver Westy reads as Naive.
IF serious AND determined to DIY ?
Then Cobbling up these and fitting them with New 604's from GreatPlainsAudio.com would Easily meet / exceed the OP's desires
I think the issue is the requirement for a 12" Westminster cab-you can't scale horns so in all probability you'll end up shorter horn and smaller mouth ergo with less bass.
I'd dump the 12" which to my ears is a very compromised speaker and go for a 15DMT or 3833/3836gg 215-which can rearrange your internal organs as a couple on here have witnessed at my place a few years back.
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