15" Or Larger 2 way coaxial drivers were there any 18" Coaxials made?

[darkmatter]

I an interested as well as my other loudspeaker projects for this year in building a large 2 way coaxial system.

Drivers that interest me as well as the Tannoy and in particular two models from Great Plains Audio their model 604-8H-III and the 604E series 2 look ideal.

The main problem is the cost of getting them over to the UK and future aftercare as I don't want to get involved in shipping to and from the UK if there is a problem

Hence my search for drivers available in the UK

Questions

Other than the Westrern Electric 4181a and the BTH K-10A 18" Coaxial Drivers, were there ever any other 18" Coaxial units made?

What UK available alternatives could I consider? I propose a system using around a 8-10 Cu Ft enclosure

Thanks

 

[adason]

B&C makes great coaxials, and they are in Italy.
18" would have rather compromised midrange in my opinion.

 

[darkmatter]

This fits the bill the BTH K-10A 18" Coaxial Driver but far too much coin for me.

I wonder if there is a modern equivalent of them?

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An externally hosted image should be here but it was not working when we last tested it.

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[adason]

You should have just searched this forum, not start new thread.

 

[Pano]

Yes, a search would help.

P.Audio used to make an 18" coax in their Blue Monster series. I've heard 2 pair, and worked with them some. Amazing driver, difficult crossover.

 

[darkmatter]

P.Audio used to make an 18" coax in their Blue Monster series. I've heard 2 pair, and worked with them some. Amazing driver, difficult crossover.

Thanks, will check this one out

 

[Zen Mod]

yeah ...... usual thing

Americans are fascinated with EU oldies , while EU boyz are fascinated with American oldies

so - Tanns are preputium priced in US , while Altec (and similar) are preputium priced in EU

just buy any 15" Tann ( patience and careful search on all add places) and enjoy

Altecs aren't better than Tann , and vice versa

 

[ErnieM]

Try to get some of the new Martin coaxials. They seem well designed.

 

[Pano]

One nice thing about the 18" coax is that the woofer cone is actually large enough to work as a decent horn/waveguide. 15" can be OK, but 18 is better.

 

[darkmatter]

Try to get some of the new Martin coaxials. They seem well designed.

I will look out for them

One nice thing about the 18" coax is that the woofer cone is actually large enough to work as a decent horn/waveguide. 15" can be OK, but 18 is better.

That is along the lines of my thoughts

 

[Patrick Bateman]

One nice thing about the 18" coax is that the woofer cone is actually large enough to work as a decent horn/waveguide. 15" can be OK, but 18 is better.

I wonder why more people don't just stick a coaxial on a waveguide?

You get the directivity of an 18" waveguide, with the midrange response of an 8" woofer.

Seems like a sweet spot; a 5" woofer won't get very loud, but anything larger than an 8" woofer is going to struggle to mate up with the tweeter. I know there are a handful of 10" and 12" drivers that can get to 1500hz, but they generally don't have the output of a modern 8" due to their limited displacement. (A necessity to get that 12" cone to go all the way to 1500hz.)

 

[LineSource]

Public Television had a series on "Building Big" which documented construction of the largest buildings, bridges, dams.

BIG COHERENT SPEAKER
Coaxial compression drivers like the BMS 4592ND are spec'ed capable of covering ~300 - 22Khz.
300Hz = 45" wavelength, which allows coherence between a large horn(like SEOS24) and large 18" deep bass woofers.

 

[Flaesh]

300 Hz is too low for 459* in SEOS24.
Distortions rising below ~444.

 

[Face]

You could possibly get away with 380hz, but 450hz is a much safer bet for a BMS coaxial behind a SEOS24.

 

[darkmatter]

From research I have carried out, it appears that the BTH K-10A and its progenitor made by Western Electric, were the only 18 inch coaxes made which had excellent performance.

Of the available coaxial units now available, 15" seems like the largest that could offer potential HiFi performance.

in particular two models from Great Plains Audio their model 604-8H-III and the 604E series 2 look ideal but alas not available in the UK.

This unit seems possible and is readily available in the UK.

The Beyma 15XA38ND

It offers a good response and a set of TS parameters that makes it usable in fairly large enclosures.

However one 18" Bass really interests me and it appears to be the only one I can find has an extended midrange response, which is this model from

Precision Devices the PDN.18BR40

I wonder how high this unit could be crossed over?

DM

 

[Pano]

I wonder why more people don't just stick a coaxial on a waveguide?
You get the directivity of an 18" waveguide, with the midrange response of an 8" woofer.

And the bass of an 8" woofer - that's why.
The idea of the big coaxial is to do fullrange with the concentric drivers. A 15" is big enough to give some bass authority, an 18" is quite impressive. Dynamic, too.

In my case, I was using the 18" coax on open baffle, so the waveguide would not have helped. I have used a 15" coax on OB with an 18" woofer under it. That worked well. Also have worked with 8" coax on OB with servo woofers underneath. Didn't care much for that.

It's all about goals and trade-offs.

 

[Adolf Corkscrew]

I don't know if the OP has already stumbled upon my similar journey regarding this issue. Granted, it's already buried under long accumulation.

The Beyma driver mentioned here was something I took a long gaze at too. And eventually decided against it. One thing to notice about the Beyma datasheet and it's FR plot is the scaling of the thing; they use something like 20dB/division on the FR plot, IIRC.

The B&C 15FCX76 I eventually purchased has proven a reasonably enjoyable performer in the end. I'm still not finished with it, though, and likely won't be before next summer. One reason being that I'm quite enjoying it already, so I make only slight modifications to the crossover every now and then; being maybe once every two months...

Now, there are other interesting 15" coaxials out there. Some Radian units, for example. But they're quite expensive, especially the ones with beryllium HF diaphragms.

 

[eriksquires]

I an interested as well as my other loudspeaker projects for this year in building a large 2 way coaxial system.

Drivers that interest me as well as the Tannoy and in particular two models from Great Plains Audio their model 604-8H-III and the 604E series 2 look ideal.

The main problem is the cost of getting them over to the UK and future aftercare as I don't want to get involved in shipping to and from the UK if there is a problem

Hence my search for drivers available in the UK

Questions

Other than the Westrern Electric 4181a and the BTH K-10A 18" Coaxial Drivers, were there ever any other 18" Coaxial units made?

What UK available alternatives could I consider? I propose a system using around a 8-10 Cu Ft enclosure

Thanks

I'm not sure what's in the US, but here's the best online dealer I know of for pro co-axials: US Speaker

 

[darkmatter]

I don't know if the OP has already stumbled upon my similar journey regarding this issue. Granted, it's already buried under long accumulation.

The Beyma driver mentioned here was something I took a long gaze at too. And eventually decided against it. One thing to notice about the Beyma datasheet and it's FR plot is the scaling of the thing; they use something like 20dB/division on the FR plot, IIRC.

The B&C 15FCX76 I eventually purchased has proven a reasonably enjoyable performer in the end. I'm still not finished with it, though, and likely won't be before next summer. One reason being that I'm quite enjoying it already, so I make only slight modifications to the crossover every now and then; being maybe once every two months...

Now, there are other interesting 15" coaxials out there. Some Radian units, for example. But they're quite expensive, especially the ones with beryllium HF diaphragms.

Thank you for chiming in a search did not find this thread

This is an excellent thread and has given me some additional ideas and thoughts written below.

I am having a similar dilemma at the moment searching for a coherent bass and treble with 15" units but am open to exploring the option of using a coaxial with an additional bass driver elements to extend the bass to as close to 20Hz as possible 16Hz would be perfect to achieve that 32' pipe.

If I reappraise the project it could end up producing two or even three speaker designs!

All units must be easily available in the UK or EU

Project 1 and the main theme of this thread.

A single 15" coax in a 200 litre box which may achieve a real nice 35Hz

Units under consideration include the B&C 15FCX76 and the Beyma 15CXA400Fe

The second project

Which would include a suitable coax unit maybe a 12" Coaxial if there is one with a better midrange than the two 15" units under consideration. Then to augment with a bass driver like the PD 186/11 the PD 184C01 or even the PD 2150. the bass volume would be around 400 litres with low tuning EBS3 alignment.

I would crossover at around 250~350 Hz or so

The third project is listed here

Cloning the BBC LS 5/1A

Where I could look at the Beyma SM-115/K and the Beyma SM-115/N both have good response to 3K and crossover to a pair of Audax TWO34X0 tweeters at 1.7Khz this tweeter as I already have 4 of them.

The BD designs BD15 is good as well as these from Precision Devices PD.153C01 and the PD.153ER

I like keep busy, AC I would like to keep in touch with progress

DM

 

[Adolf Corkscrew]

Both the Beyma and B&C units should be easily available in the EU. I acquired my pair of 15FCX's from ProAudioWebshop.nl in the Netherlands:

B&C 15FCX76, ProAudioWebShop.nl

I'm not sure if they've updated their webpage yet, at the time they did ship within the EU, but didn't state it anywhere on their pages. I made my order via e-mail. From experience, they can be trusted.

Of course you can shop locally in the UK too:
B&C 15FCX76 15 Inch Coaxial

Slightly more expensive at the current pound/euro rate, but shipping might tip the scales in favor of local sourcing. They do weigh around 20kg a pair, and the box for shipping a pair isn't exactly going to fit through your mailbox.

And sure, keep in touch DM. And I should try updating my old thread, but there's currently not much documented meaningful progress to report there. Currently enjoying Dire Straits' Love over Gold spinning on my Michell Gyro through a load of tubes and out of those B&C's.