Building a big two way system, a homage to the KEF BBC LS5/1A

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The BC1 is a unusal 3 way design in that it is a classical two way design crossed at about 3 kHz and then have a third driver above 10 kHz. At the time they could find tweeters they were happy with all the way from 3 kHz to 20 kHz, but later designs scrapped the supertweeter as it was no longer needed when better domes was avaible.

Another reason for going to three-way was that it was taxed at a lower rate due to being a "professional" speaker.
 
2 way hi efficiency speaker 2 way with a 15 inch woofer??? they are not many 2 way speakers that can sound good on music with a 15 inch woofer....any good 15 inch driver will have a high eff of at least 97DBW not many tweeters can keep up with that under any normal power of like 20-100 watts....even if the tweeter is crossed over at 2k... and I dont ever remember any 15 inch woofers that would work well up at that freq.. they are some that are close... but most?? good woofers need to crossover at 1000hz or so... and even thats at the limit..

IF the speakers are going to be used for music ?? the altec 416-8C is a good choice.. it can cross over at 1200hz.... only problem with using that speaker is you need a really good hi end driver to keep up with it !!..maybe i'm wrong but crossing any 15 inch speaker over at 2k is not going to work good for music....
 
I was revisiting an old design from the 1950s, and already have the drive units and crossover attached to an original baffle. Still haven't done any more with it 'though!

The LS5/1 was a BBC designed studio monitor speaker, made in the days when radio and TV sound didn't go above 15kHz, and wasn't even stereo in the UK.
 
Somewhat closer to four years and still no progress with this.

I have found some candidte drivers which are close including the Audio Technology Flexunits 15" which is a polypropylene cone with a well behaved rolloff

A couple of other units are possibles including the 18 Sound 15NW530 which is fairly well behaved, this one could be EQ'ed when dealing with baffle step response with a larger series inductance / parallel resistive network.

15NW530

Others include the Precision Devices PD153ER which is a possible as it can be used with small format compression drivers, again this will need EQ.

Anyway I will model with these two 15" units.

I will be using two tweeters like the LS5/1A bit with one gently rolled off at 5-6 K or so
 
The RCF L15/554K is a 15 inch woofer a wonderful sounding midrange and you can use it to 2000Hz with the right crossover.I had a simple system with these and some horn tweeters in my student days and they sounded fantastic.They also have really good textured bass.A classic driver and bass guitarists love them-which is why they are still being made after 30 years.
I have owned most of the classic Tannoy 15 inch dual concentrics.The L15/554K has that sort of special midrange.


You would have to attenuate them to match the HF1300 .
 
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The RCF L15/554K is a 15 inch woofer a wonderful sounding midrange and you can use it to 2000Hz with the right crossover.I had a simple system with these and some horn tweeters in my student days and they sounded fantastic.They also have really good textured bass.A classic driver and bass guitarists love them-which is why they are still being made after 30 years.
I have owned most of the classic Tannoy 15 inch dual concentrics.The L15/554K has that sort of special midrange.


You would have to attenuate them to match the HF1300 .

As an aside to the main thread topic; a diversion

Yes an interesting driver, wonder how it would work with the Beyma 200-TPL
 
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