Acoustic Horn Co.

Number one.......... a general survey

2013-04-24T13:48:00.000-04:00

I thought I might give my opinion about the "number one" best speaker.
Well there is no number one. There are a number of "ways to do it"... and I have made a list below.
Quad Lowther ( or similar) 6" +1" dome tweeter ( most popular)
RCA LC1a in a world of its own.
Advent with an upgraded crossover. ( let me know if you find a box this size with better bass)
Planar designs
Pleated membranes ( Heil)
Pro driver designs ( P.A.) Horns

Each one of these has "something" that can not be done by the other.
A lowther big magnet wide range has a peculiar voice quality that is tough to beat.
Quads are in measurement terms..perfect..; but dynamic range and output are a problem.
A standard two way 9 6'+1' dome ) are inexpensive, small , but suffer from dynamic range and too much of a load placed on the tweeter in the voice range. ( distortion at higher levels, directivity, and crossover right in the center of the voice range )
The Advent is a wonderful speaker, needing only a crossover update. It has a unique teeter ( now in vogue in esoteric domes) The woofer has a copper voice coil bobbin to control inductance. The center dome is open .. no unwanted output. ( I suppose if you added a phasor you could extend the upper range of the woofer a bit) The tricky forward mounting of the tweeter-- so the baffle is used to control reflections from side of enclosure. And the odd bi-filer winding of the voice coil..I am not sure why they did this.. (maybe economic?)..... and the bass... Well done Mr. Hoffman.
Planers and Quad all have directivity , distortion at high output ( lack of dynamic range) problems,
Very good acoustic phase, and the ability to reproduce a squarewave. Overlooking the issues. they are very accurate.
A few overlooked speakers are the .....
Manger, Lincoln Walsh, and keele" CBT line array. ( Audio Artistry ), and Tom Danley.. IMO the best designer today.

As far as horns go.. well it is the best compromise of other systems....
I refrain from being number one.............. bill

RCA 1958 - High Fidelity...

2012-11-28T23:11:00.003-05:00

A New Orthophonic Stereo 1958 or so

Frequency response

Release of the AH 600

2012-07-02T12:01:00.013-04:00

The new AH 600 is a 80 x 40 radial horn.
Based on the industrial version, the AH 500, the AH 600 has an integrated stand, and beautiful proportions.

It is true, "form follows function". The shape of the horn was derived from the radiation pattern, low frequency cut-off, and time alignment considerations.
It has excellent measurement characteristics, and is designed to work with 2", or 1 1/2" drivers.

This is the most natural sounding radial horn available today, due to the proprietary radial/conical geometry.

Price to be announced

Best, Bill

Acoustic Horn Co. Cinema project

2012-05-23T16:25:00.019-04:00

I have just finished the sound system speakers for the Aron cinema conversion to a digital projection system.

This is a state of the art system--and the Aron is rare in that is in a small town. Perhaps the only one in Canada.

This system has a large center channel 4 foot basshorn, and two 18" woofer folded pipes for bass.
8 side fill speakers, and two left right screen speakers.
I can't wait for Prometheus!

Thanks to Aron cinema for images.

Bill

Concept stand for new AH600 horn

2012-04-17T19:01:00.003-04:00

Horn Day Is Here!

2012-02-10T12:26:00.001-05:00

http://internationalhornday.wordpress.com/

DSH horn vs CD Horn and .......making bread when sales are slow and Loudspeaker Group stuff.

2012-01-24T12:58:00.005-05:00

Best of the Season!

2011-12-22T10:32:00.002-05:00

. and frequency response of horn with JBL 2447!

Ho Ho, Bill

2011-12-18T12:23:00.000-05:00

testing the first few inches...........

2011-07-11T15:57:00.000-04:00

Some throat test shapes Made years ago, before conical horns........

Aristocrat

2011-01-08T11:56:00.000-05:00

Aristocrat with University co-ax .

Here is my Uncle's EV Aristocrat on a table in my livingroom.

It has good "punch" and smooth top end.

It has limited bandwith in top and low end.

Still, a nice speaker. There is a post some time ago with pictures.

open RRS Feed to see all old posts.

Best of the Season, Bill

150Hz horn test RCA1428b TAD4002 WE 555w

2010-12-31T16:51:00.000-05:00

The horn is 6 feet long.

The RCA 1428b vs a modern driver

2010-12-17T15:33:00.000-05:00

Here are test of the famous RCA 1428b, much praised and misunderstood on occasion.

The 1428b has some of the clearest voice reproduction available. As it only goes to 12Khz, it is overlooked as it might appear s bit "dull".

The TAD 4000 series is one of a very few select drivers that can compare.

These curves are on the AH 300 at 0,10,15,20 degrees.

Any of you that don't want those old RCA's...I live in Canada--I'll pay the shipping too!

555w Fun!

2010-12-08T15:27:00.001-05:00

Here are some tests of the famous Western Electric 555w.

The horns are a 4x5 multicell ( it was a Racon I think) and a very old Edison phonograph horn.
Note it is a conical horn, and the same type of horn was used to record the wax cylinders. An exponential horn was never used, due to it's "horn-like" tone.

Soon I will post a 6 foot exponential horn with various drivers as a test of how low compression drivers can go relative to distortion

AH 300 Horn Stand Released

2010-11-22T13:05:00.000-05:00

Finally!

After much design time spent in the coffee shop ( years) the AH 300 horn is in production.

It will fit any AH 300 horn, and by drilling new holes, the horn mouth can be rotated to sit on a flat, rather than a point.
The AH 300 stand is made of 3/8 plate aluminum, and powder coated black.
All holes pre-drilled to fit wood screws that attach to the horn mouth.

Very sturdy, capable of accommodating the heaviest compression drivers made.

Price is $275.00 a pair

2010-08-11T11:55:00.000-04:00

My Wife and I were married at the Moravian Tile works in Doylestown Pa. in 1972.
I was thin then! My wife, Dorothy is just as beautiful, and deserves an award for thirty years of horns.

We had a gigantic sound system consisting of a full size 60Hz Hyperbolic horn and four RCA LC1A speakers, powered by a 60 watt Acrosound, and a 100 watt Grommes tube amplifiers.
The horn was built in 1969 for a hammond B3 organ.

The basshorn had two RCA 15" field coil woofers, and the top end consisted of Western Electric horns and drivers. Notice the the orange horns are conical horns ( three in a row).

We stored the horns at a nearby friends house. His name was Mr. Clemments. He worked for RCA, and said Harry Olson was his boss. He had an immense library of in house RCA journals, the RCA Review. It was the size of a set of encyclopedias.

I read as much as I could, but I never finished as I got married a day later!

I have never seen or heard of these volumes since.

Bill

Interesting Things

2010-07-28T12:36:00.000-04:00

Some of my collection. The first one is a battle anounce speaker used on D-Day in WW two.

Next is a large RCA 10" voice speaker, a RCA 1428b on Twin Power horn, and Lansing field coil coil woofer.

...............and my shop.

best, Bill

News from Down Under.......

2010-04-15T10:53:00.000-04:00

Simon, from Australia, Has a purists system, perfect turntable, really nice amp, and lives in a terrific place.

Hey Bill
1. The Ah 700 horns are running and they are beautiful – very happy with the sound . Soundstage is wide and instruments place precisely. I have been switching back and forth between the Ah horns and some 550 hz tractrix on the same drivers – Your horns are clearer and the treble much more precise and sweeter. They are clearly more neutral. Midrange tone is beautiful
I am still running tractrix for the midbass – the horns are cut out but not yet assembled – too busy at work at the moment but will let you know as soon as they are done
The sound is noticeably less open as you get to the cellos as compared to the violins – the conical are definitely more clear and wide open.
I am very happy with the horns but just to let you know the mounting brackets did not fit once bolted to the driver – the bolt circle is inside the flange on the horn so took a couple of hours with a file to get them to mate – just for future reference .
Thanks Simon

----------------------------July 19, 2010--------------Hi from Bill
Hi Simon,

Thank you very much for your kind words. I'm glad to hear the sound to your liking.

Many years of work and testing have gone into the AH700.... your comments are echoed by others who have AH! horns.

I would be glad to send you a new stand. Filing aluminum is not the most fun.

I now have a precise jigging system and threading machine.

When you get your mid horns going, let me know.

Best,
Bill

------------------------------------------------------------
Hi Bill

My Stuff does not get into boxes very quickly ( thankfully have girlfriend who appreciates the sound rather than the looks ) so most of it is not photo worthy.

The amps are DIY single stage rs241 – parafeed and the photo shows a separate power supply

I use K+K audio phono stage and the Semi DIY table with a Teres signature motor pod and an advanced analog air bearing tonearm with a zyx cartridge

PS, not sure if i said it but you are very welcome to publish any comments

S

From Across the Pond......

2010-04-07T11:24:00.000-04:00

Pete has the ultra fabulous RCA 1428b field coil driver mounted the the AH 300.

He hails from England.An electronic engineer, he has designed his own passive network..really a good job too!

Networks are very difficult

"'I have attached a few pics of the current setup. If I had to describe them in a few words, I think it would be "natural", "effortless" and "sweet". I'm currently using an Audio Innovations First Audio 2A3 push-pull amplifier - I'm in between projects and this is my stop gap amp; not bad, but not the last word. My deck is a Technics SP-10 in a double layer slate plinth, with an SME V-12 arm and Audio Note Io Limited field coil cartridge. Some pics attached also. I'll soon be replacing the deck with a Voyd Reference, which I recently heard and loved - it's a toss up between the Voyd and Technics, but the Voyd does more things right to my taste.

Cheers,
Pete

This time with attachments!

Thanks Bill,

Yes, I had to say these sound *incredibly* natural and there's not a trace of the horn "honk" to be found. The "peak" at 1kHz is not really audible, but I will definitely experiment with a low-Q notch filter. If you have any suggestions, I would welcome them along with any crossover designs so I can compare.

They are sounding absolutely wonderful (more or less tuned by ear). The measure pretty flat, too (see attached). Possibly a touch rich in balance, so I might raise the midrange up a dB or two by adjusting the LPAD (currently at about 10db!).

All the best,
Pete"

AH 700 in Quebec, Canada

2010-01-21T15:12:00.000-05:00

Hi again Bill,

Here are some pictures.

This system is very dynamic, precise and analytic. Every instrument is reproduced with astonishing realism. No detail is hidden. TAD compression drivers with Beryllium diaphragms are among the best that money can buy. The use of the AH Horns added smoothness and a clearer articulation to the sounds that the TAD reproduced. In fact I tried many horns in the 800 Hz to 12 KHz range, the most important part of the audible spectrum, and none did better then the AH horns (...yet...). Period.

My main sound source is an Oracle Delphi turntable with an Alphason tonearm. A Shure V15 type V cartridge is mounted on the arm and connected to a Hiraga phono preamp. A Krell preamplifier then sends the signal to a pair of modified Rane AC23 electronic crossovers. All the speakers used have a dedicated amplifier. Its a five way active system.

The lowest frequencies are reproduced by 2 JBL 2235H (15" speakers) mounted in an Onken enclosure tuned to 25 Hz. A bridged Bryston 4B SST amplifier is used here.

My satellite speakers are all horns. Bass is taken care of by 4 Altec Lansing 515B speakers mounted by pairs in a modified JBL 4550KBA cabinet. Two Basic M2A Kenwood amplifiers, with sigma drive circuit, are use here.

Mid frequencies are reproduced by a pair of JBL 2482 compression drivers. The original phenolic diaphragm were replaced by Radian diaphragms. Those drivers are bolted to a JBL 2350 horn.

Mid high frequencies are taken care of by a pair of TAD 4002 drivers married to AH horns (in fact this is the cherry on the sundae...).

High frequencies are reproduced by Fostex T-925 horn tweeters.

Mid and high frequencies are all amplified by Basic M1 Kenwood amplifiers, with sigma drive.

My system was adjusted (in the listening room 33' X 18') with a real time spectrum analyzer using 1/3 octave equalizers.

Best regards,

Maurice Daignault

In Good Company...........

2010-01-13T18:02:00.000-05:00

Here is Walter's AH500 with the fabulous RCA 1428 electro magnetic driver, the HF component of his massive RCA theater system. ( four radial RCA basshorns!)
One of the best drivers ever made......

"Hi Bill,

I would have sent this sooner but yesterday when I went to take a
picture I made the mistake of turning on the system to listen and
after two hours had gone by l realized that the light had failed.
I've always thought of a music system as a time travel machine and
this one certainly has the power to transport me. Lifelike, clear,
realistic, powerful- take your pick of adjectives and use them
wherever needed. These sit on top of RCA field coil bass horns and
the 1428B matched to the AH! 500 certainly keeps up. Twice recently
different people have asked me if this was "better than live".
I just smile. I love my horns.

In your debt,
Walter

New Pricing

2009-12-16T19:06:00.000-05:00

Staring in February, there will be a price increase on the AH 700. AH500, and AH700.

The new prices will be listed in a day or two, but not active until February 1st, 2010

They have been sold at a "break even" point until now.

The best of the Season to everyone!

Bill

a Christmas Horn!

Acoustic Horn Company creates designs for RCF Speakers...

2009-11-04T15:37:00.000-05:00

Acoustic Horn Company develops designs for RCF P.A. Speakers.

Click here to visit Bill Woods Design page at RCF

A year's research under contract from RCF has led to the development of these systems.
Designed expressly for High Power P.A. , RCF Precision drivers are a benchmark for high quality transducers.

I might add, RCF is an absolute pleasure to work with.

Best, Bill

The Vitavox S2

2009-10-25T15:00:00.000-04:00

Here are curves of the famous Vitavox S2 on the vitavox radial horn.

Jonathan graciously allowed me to measure it. Despite its popularity, no one has posted a clear curve

Here they are.............

Radial horns always have the smoothest curve ( but not the best sounding)
Shown compared to the RCA 9584 driver on a 350Hz tractrix for comparison.
It is a very nice driver, but needs a HF horn.

Muticell horn tests

2009-10-03T16:28:00.000-04:00

Here are some muticell tests of an RCA 4 x 5 with RCA 1428b (two) Altec 2 x 5 110 deg with Altec 288 driver.

A single cell of the RCA 4x5 at 0 deg an 10 degree
For comparison a JBL 90 degree - deg.

The muticells all measure almost exactly the same off axis.
The JBL horn is down 5dB 45 deg off axis.

Here is PDF of JBL 2553 horn. Note horn is eq'd flat to show off axis curves.

Best, Bill