Over the years I've had a few of Martin Seddon's Azura horns. They are tremendously impressive - there's nothing else like a horn for dynamics and "you are there" sound quality.
But I've never been able to live with them for long term. I need speakers that are accurate, and whilst its possible to use all sorts of implementation to get anything accurate these days, it isn't always agreeable.
Horns do have a "horn" sound - some call it a "honk" or "quack", but its just a slight tinge to the midrange that cuts a little naturalness from the response. Or at least that is the impression I've always had.
My Supravox 215 field coils in a large OB (see previous blogs) are the most natural and musical speakers I have , amongst my 4 systems set up in my (big) listening room.
All the previous horn systems I've had used bass reflex, Onkens or sealed enclosures for the bass frequencies. I've never had a full horn system where the bass is also produced by a horn.
The reason for this is that bass horns that can go down to the necessary 40 or 50Hz are BIG - they need a lot of floor space and dedication to own.
However I've always wondered if a horn system really needed to be a complete horn package , where bass, mid and treble are all covered by dedicated horns, and the resultant synergy produces a sound without compromise and weakness's.
Listening to Martins all horn system piqued my interest and for too many years now I've had a set of his 160Hz Azuras , with the intent to build his matching 50Hz bass horn.
Martin uses the Line Magnetic LM555 field coil compression driver in his 160Hz horn. Its not cheap at $US5000 a pair. Its a direct copy of the very famous and desirable Western Electric 555.
The Atlas PV5-HD costs about a tenth of the price and is reported to have been based on the WE 555, with some compromises, a phenolic diaphragm, alnico magnet etc.
Martin suggested that it could be quite good in the 160 so I ordered a pair and we did some measurements that were very encouraging.
But this time I definitely wanted a full range horn system, and the picture you see here is the result of a very intense week of woodworking.
The bass horn is time consuming to cut out, and surprisingly quick to assemble.
Its a L shaped horn, which gives the horn length in a reasonably compact shape (and appealing to a Ducati L-twin owner!)
Cut off is 50 hz, and simulation looked very good.
The driver is a Supravox 285 RTF , courtesy of my friend BobM , and ideal for this situation.
At this stage there is no enclosure behind bass driver, but building that soon. It can be used with or without enclosure.
With Enclosure
The 160Hz horn is mounted above the bass with wooden supports , and the treble tweeter is between the two.
The tweeter is a Yamaha horn with JA4281 compression driver- fairly common but it does the job.
The crossovers are something I just cobbled together out of my junk box to get it going - simple 6dB slopes with an inductor on bass, and caps on mid and treble for crossover points at 300Hz and 2KHz.
Martin has a lot of experience with some sophisticated lower order crossovers (?) and I'll be investigating these soon.
Seperate amps for all horns, so 6 tube amps, all with level controls for very fine adjustment of tone.
Its consuming, but active/passive gets the results I require.
So how does it sound?
Well if you've only heard horns with non-horn bass , you haven't heard a horn system!!
The most obvious thing is the very low levels of distortion, bass is very clean and defined , quite different from conventional moving coil drivers and just so involving to listen to.
As is the midrange , that "honk" is virtually gone, and I think further work with crossovers/amps/adjustment will eliminate it completely.
I get tired of trying to describe sound , so I'm just going to say its as good as I've heard.
It takes a little re-conditioning of the mind , as there is so much that is so different , that you wonder if it is "too good" , but it soon becomes obvious that this is what it actually does sound like.
Then I just put record on after record, as if hearing them for the first time, and its only early days for this system!
I'ts a shame most won't get to hear something like this, let alone have the space (and dedication to fine music) to actually build it.
http://www.azurahorn.com/index.html
