A 4-Way Active Horn System

[Non-Smoking Man]

I propose to produce a 4 way version of the 5-way system (see a 5-Way Horn System thread) which has sufficiently less 'real estate' to enable both transport and installation in other venues than a home, whilst retaining much of the SQ and SPL capability of the bigger system.

One goal is to demonstrate a fully balanced, active horn system (not a hybrid) at the next Wam Show.

This system will use equipment that is already on hand in the 5-Way set up or alternative equipment collected on the way that could have been used in that system.
For example, I can lift the tops (1.5" JBL 2435Be, + supertweeter),, which are on a platform straight off the frames at home and secure them to a fresh support system.
And I can utilise a pair of Trapezoidal cabinets that house twin 15" drivers that I have been storing for several years, together with the 4 JBL2225J drivers for them, that have also accompanied me from flat to flat.

I have become accustomed to and have been working towards balanced systems for a number of years now and my smaller record fair system is also balanced. I could 'borrow' my balanced phono stage from that system and match it up with my recently returned Django passive TVC pre amp (thanks Jessica_k), that will pass to my Ashly 4 way 4001 active analogue crossover and on to 4 amps (3 valve for mids and tops and a muscle amp for the bass).

It should be movable and relatively versatile regarding room size, (or hall size).

Needless to say the front end will be a vinyl player ( I can choose from several).

An exciting project for me and, hopefully, one which will attract paying customers at the show as well as giving members a unique taste of what horns can do.

Jack NSM

This thread will chronicle the assembly of the system with all the twists and turns you might expect, plus some snaps of the work as it progresses.

 

[robbie010]

Watching with interest!

 

[Non-Smoking Man]

Ive got a Furman PL-8C E 'Power Conditioner' here that is part of the late Joolz collection.

(I use a Pure AV conditioner in the 5-Way, partly because it has 8 sockets, and is convenient, perched as it is on top of one of the subs. (We cant reach the wall sockets anymore..))

Its 220-240 volts so that's ok, but it has IEC female socketry. Ive got 5 cables that c/w the thing, but I need 8 (or thereabouts). It has provision for 10 plugs. Better get busy finding 3 more..

It would suit my purposes to press gang the Furman into the 4-Way. This leaves the PureAV where it is. My policy is to leave as much of the 5-Way in place as I can.

There is a visual plus as its slim and black and will match the incoming electronics. Bonus!
(The 5 way is a dog's dinner system, but I will make an effort with this show system. Never know with Hotel mains and us lot plugging in a conditioner might be an asset.)

One of the amps I hope to feature in here is a Parafeed amp made by Disarmament of this Parish. I have high hopes a 2a3 will do a great job. Ive just got to pay for it now! Its top priority!

Jack NSM

 

[Non-Smoking Man]

The 4-Way will be balanced throughout - this is dictated by the external active crossover I will be using (Ashly 4001) as this is balanced only.
I will probably plump for my Thorens TD124/Wilson Benesch/Art 9 front end as that is balanced already and its a known quantity. I have just bought a new belt for it and there will be a new marble plinth with a wood surround to match the rest of the system (as opposed to the varnished ply its in at the mo').

I discovered a rack under my bed (flatpacked) and I recently bought a Block - they should come in handy.

I may choose my Iota-By-Design balanced phono stage and the DIY Supply 'Django' passive TVC to go with it. The latter has the prized Stevens and Billington transformers. I'm not concerned about any lack of dynamics through a passive as the horns have plenty going for them in that respect. Should be a nice 'balance'.

Amps? I will have plenty to choose from.
The intended midrange driver is a 2" compression driver - more details on that later.
Tops are my current 5 way stars - JBL 2435be and the more workaday Visaton ring radiators. Fostex T90, or 900 going spare anyone?

Jack

 

[Non-Smoking Man]

Some more ideas for the more technically - minded, mostly gleaned from googling 'horn theory' and looking at the Troels Graveson website, in particular the essay 'Loudspeaker 2'.

Loudspeaker 2 is a 4 way hybrid floorstander (pictured on wheels) with a hornloaded midrange/top and supertweeter as the top two levels (-10" mid and 18" bottom next two down).

Re suitable supertweeters he lists two types that I own: the Beyma CP21 and the Visaton 16. The Visaton is what I use in the 5-Way and the CP21 I have as another option. He likes them both and further mentions the ubiquitous JBL 2405 and its 77 alnico brother. Not recommended is the Fostex T90 - that's off the list then! I note that Graveson marks the CP21 as inverting polarity. Must get mine checked.

The 1" comp driver he uses in Loudspeaker 2 is the 18SoundNSD1095N. I read a review of it and its a beauty, with a number of desirable features and advanced design and materials. N is for Neodynium, of course..a compact, powerful modern magnet material. I have a pair of waveguides that would match this one. Goes on the wishlist for a future project - as does the BMS 18" 18N862 driver for a possible future hybrid speaker a la Avantgarde. (That is, direct radiator bass and horns above (x3 - mid, top, supertop).

I was well pleased to see my Visatons up there recommended and I may cease my search for the upmarket Fostex 900s.

I have to sort out xover points for my system and these are determined by the cut off frequencies of the individual drivers: JBL 2235J, B &C DE - 750 (2" comp driver) (reputedly used in Klipsch speakers rebadged) , JBL 2435Be (1.5" comp driver), Visaton H16 (supertweeter). Modern 2" compression drivers can easily go down to 500Hz and reach 5,6KHz if necessary. I might just take it to 2 or 3 KHz before bringing in the JBL. The Visaton I will leave to light duties north of the excellent beryllium-diaphramed JBL. I'm not having to stretch these drivers' frequency abilities - it doesnt do to do that.

Slight concern is bass extension: I'm having to resort to 15" drivers (2 a side) rather than 18" and the 2225 resonant frequency (their lowest frequency) is only 40 Hz. In a horn it might go down to 35Hz. They might do..we will see..

Jack NSM

 

[Non-Smoking Man]

Ive found a couple of useful essays for those who would like to delve into horns without the technical detail provided by Kolbrek (although that is excellent (and exceeds my capabilities)).

They are: John Burnett's piece in Lenard Audio Institute; the essay in Six Moons site and a couple of entries in 'What'sBest' Forum.
Plus the seminal work by Jack Dinsdale and on the Volvotreter site (and reproduced elsewhere - Enjoy The Music) essays by Bruce Edgar.

...Jack.

 

[Non-Smoking Man]

There are a number of ways to skin the cat regarding horn bass and I want to discuss one of them - the scoop bin.
(There's a good deal of agreement that a horn system benefits from hornloading throughout as opposed to having a direct radiator for the bass and horns upwards.)

Living Voice produce a scoop binned horn speaker system. Its called the Tone Scout.

Ive heard this speaker being driven by a top class Kevin Scott system comprising a SME 20, SME V, IO cart, AN electronics (Ongaku) and the Tone Scouts. They use a Fane bass driver a GP1 Vitavox compression driver and I think its a JBL 2305 tweeter. It was excellent. (Owned by the late Doctor Bunn.)

Most of my research was internet -based and involved delving into a Forum I used to belong to - Speakerplans.

On the value of scoop bins ( a rearloaded horn attached to a direct radiator visible from the front, often shaped in a curve, hence 'scoop') opinion is divded according to the pro audio world.

The problem is getting the rear emission in phase with the directly radiated pattern. This is not easy.

A second problem is getting low bass from them, especially as a single. Horns 'couple' and a stacked quad appears the favourite option to get down to 50 Hz, i.e., 4 a side. (Not really acceptable in domestic hifi.

So, what to do domestically?

And how on earth did Kevin Scott get the bass required out of the Tone Scout? Answer - subwoofers.

Is there a scoop bin that can be pressed into service for domestic use that can avoid the issues Ive alluded to?

I'll try to find out..

Jack NSM

 

[Non-Smoking Man]

Domestic hifi 'scoop bins':
I had a listen to nak's Kochel K200s a few weeks ago and I'm going up again in the near future with Jessica Kinchin to have another audition.
An interesting design with an 8" bass mid and a conventional soft dome tweeter. The bass is loaded by a scoop taking the rear emission folding it, and allowing it to expand exponentially into the mouth which gapes at you from the listening position.
They are quite nice and initial impressions favourable.

Progress on the 4-Way:

The B&C 2" compression drivers were presented to the multicell waveguide intended for them and they came together nicely. They have been rescued from a dampish garage and are on the landing at present. Looking good - though Ive never played the De 750 comp. Trusting they work..

Looking forward to a mock up on the 'patio' in the New Year sometime. My idea is to perch the multicells on top of the Trapezoidal bass cabs on supports and have the tops (a board holding both the 1.5" comp and tweeter) clamped to a pair of Partington Broadsword speaker stands behind them. (Driver alignment by eye..)

The Traps go in the Mondeo estate - just. We need to invert one to fit both.

Jack

 

[Non-Smoking Man]

When you are contemplating doing the Wam Show good use of space in your vehicle is of paramount importance.
So, it was with great interest that I discovered that my second choice of supertweeter, the Beyma CP21, is rated at exactly the same efficiency as the driver below it - the DE 750 (105db/w).

This opens up the possibilty of driving both stages (midtop and top) with the same amp off one level of the analogue xover.

That would mean I only need a 3 way crossover: bass, midrange, and, thirdly, mid/top+supertop.

I dont actually save much space (one amp) this way, but I have another Ashly crossover that's 3 way, so I'm reducing interference to the 5-Way installation (one of the goals, see above). (And this is an advantage because of the lack of access to the main system.)

Coolio!

It might all go in the estate yet..

Jack NSM

 

[Hornucopia]

I once got Avantgarde Duos into a Lexus LS400 car.
I still think you need a Citroen CX Safari! (Or Volvo S60 estate)
Or a VW van?
Good luck. -and enjoy the music!

 

[Non-Smoking Man]

I once got Avantgarde Duos into a Lexus LS400 car.
I still think you need a Citroen CX Safari! (Or Volvo S60 estate)
Or a VW van?
Good luck. -and enjoy the music!

We have a van hire establishment (Bognor Motors) 100 yards from our front door that specialises in VW Transporters.
Ive used them 2 or 3 times to move my daughter round the country.

Its the fallback option.

Jack

 

[Non-Smoking Man]

Ive come up with another alternative 4 way system that maximises existing equipment:

Level 4 (top) Beyma CP21 105 db, wide dispersion (suitable for broad seating pattern) (have);
Level 3 (mid/top) 18soundNSD1095N 1" comp driver (not have) plus 18sound waveguide (do have);
Level 2 (mids) Beyma 8" M60/N (95db/w) direct radiator (have); cab - to build;
Level 1 (bass) IK Audio 18" (2241) JBL-loaded folded horns to place in the corners (98db/w).

The folded horns go in the corners for added loading as opposed to half space loading against a back wall, increasing extension, and the rest would be a standmount arrangement of some kind inboard of the subs. This would sacrifice sub bass time-alignment in favour of bass extension. The question would be if the 8" mid speaker met the subs w/o a hole in the response. (The 8s go down 120Hz, the subs will be pushed to do 110 Hz in a horn.)

Ive got the amps, crossover and front end of course.

Jack NSM

The 18Sound combo I owe to Troels Graveson 'Loudspeaker 111', recommended on his website. Looks very exciting. Such a device, correctly loaded and crossed, would be more than a match for most comparable domestic hifi equivalents. The drivers are £300 a pair.
P.S. I'll defiinitely need a van for this lot!