Beyond the Ariel

Any midbass horn is going to have trouble getting up to 700Hz easily, especially if the lower cutoff is below 100Hz, or the driver is 15in. Inlow has a 100Hz horn that might get close using a 12in driver.

inlowsound.com

I don't seem to have a problem finding them, although I wouldn't do it myself :)

What he's actually doing if he builds it the way he's talking is he's building a four way with horn loaded mid spread among two drivers./horns

It would be a real pain for me to switch drivers in my midbass horns to show what some are capable of but here is a thread that shows a 15: driver that goes way out past 700 Hz in a midbass horn.

http://db.audioasylum.com/mhtml/m.html?forum=hug&n=167673
 
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A 10" driver on a mid horn will eat a 15" alive in both the sound quality and in the dispersion pattern control. I just don't understand anyone making a 15 work over about 600hz if it is mounted on any kind of horn, makes no sense to me at all.

I agree except I'd leave out the "if mounted on any kind of horn" out.

With the exception of maybe a Tannoy Dual Concentric or similar 15's are pretty useless to me above 400 hz or so. Of course crossing over that low with his treble horns will be a disaster
 
POOH,
I guess I should have said any horn I would design would work better than a horn with a 15" mounted on it for 600hz and up or 400hz if you prefer that frequency, how about that. Any 15" is going to break up above the pistonic range and will just beam at those frequencies. I did my first 10" mid horns in 1977 and showed them at an AES convention. I don't think anyone else was using anything smaller than a 12" at the time.

I use small 6" horns for my home system designs.
 
POOH,
Originally when I designed the mid horn it was based on a Polydax PR17 driver. But I am building my own speakers now so wouldn't use that pro driver anymore. I would probably redesign my own 6 1/2" driver as it is a high excursion drive and that wouldn't be needed in this application. The top end I have a small horn for 1" drivers and originally I was using TAD 2001 drivers but those are just way to expensive now to consider. I haven't heard any of the recent Radian drivers, I have used them in the past but they always had some problems around 16khz, a resonance in the mechanical assembly. So perhaps a B&C or one of the other European drivers. On the bottom end take your choice of a good 15" driver and you have a nice three way system.
 
The Polydax/Audax PR17* are a long time favorite of mine - The new Celestion 1" drivers are really clean and to me sound better (very natural and measure really clean) then the TAD 2001 in their range, I'm talking about the CDX1425. It will only works down to 2K or so though. The Radians to me (475) sound soft and a bit spitty at the very top - I think the radians problem you describe is waht I hear in the top - it probably is in their clamping system for the diaphragm, really a mess in my experiance
 
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It's been a long time since I had to deal with the Radian driver problem. A friend of mine use to work for Radian and knew the fix for the driver resonance problem. The simple way that I remember but not the best was a notch filter up high for the problem. If I remember correctly the real fix was a modification to the middle of the center phase plug section. I think it took a specific drilled hole in that section to act as a resonant trap. Can't say I remember the hole size or depth but that fixed the problem. The Mylar surround on those drivers is fairly stiff and they are still using it after all these years.
 
The reason I set aside the TD15M for this project was Gary Dahl's one-year wait for a pair of TD15M's I ordered for my own prototypes (I asked for them to be shipped to Gary D for initial evaluation and testing.)

The wait for the beryllium diaphragm version of the Radian 745Neo was longer than that, but that was for an item that required new design. There was always the possibility that Materion had signed a contract with JBL giving them first rights to the technology, and there's no way of knowing how long that exclusive contract might have run (since it falls within the scope of NDA agreement). None of my business; I'm just a potential customer for Materion and Radian, and don't buy these things in the hundreds or thousands, as JBL would. As it turns out, the beryllium version of the Radian 745Neo made its first appearance in November or December of 2013, and is now in regular production.

From what I've heard, the one-year wait for the TD-15M was the result of a Chinese frame/basket supplier not delivering product, or maybe going out of business. I don't know the details of what happened. Gary did eventually receive my pair of drivers ... minus the polished aluminum phase plug, which arrived a month later. Since I'd already decided on the GPA 416 Alnico six months before, I had Gary sell the pair of TD15M's.

How would would the TD15M sound in a 2.5 cubic foot closed-box with a 700 Hz crossover? I don't know, I haven't auditioned it. The only two drivers I've directly compared are the current-production JBL 2226 and Great Plains Audio 416 Alnico (8-ohm version).

The new speaker is a limited-bandwidth 2-way system (60 Hz to 12 kHz) that uses independently powered subwoofers in the 20~60 Hz region and optional supertweeters in the 10~20 kHz region, depending on the choice of diaphragm material for the compression driver.

The new loudspeaker is a modern version of Jim Lansing's Iconic studio monitor, which first appeared in the late Thirties. The basic concept of a 15" paper-cone bass driver and HF compression driver has been around for eighty years.

Here's a picture of Les Paul, famed guitar player and pioneer of multitracking, with a Lansing Iconic monitor in the background. The amp-looking objects on top of the speaker are very likely field-coil power supplies, which means the speaker was probably built before WWII.

Hi Lynn, sorry for the question I am just catching up on over 30 pages of reading. Is this latest iteration, the modern Lansing, a new design or the same as the one described in post 10631?

Does anyone have thoughts (sound quality, design, etc) on the Klangfilm speakers, ie Bionor?
 
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Tis time to revive this thread :). Here are measurements of the Radian 745 Be on the AH425 horn. The top curve is at horn mouth. The bottom one about 1 m away from horn mouth. The driver is low pass filtered (3d order) and padded about 15 dBs via an autotransformer. Gate duration about 2 ms.
 

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Tis time to revive this thread :). Here are measurements of the Radian 745 Be on the AH425 horn. The top curve is at horn mouth. The bottom one about 1 m away from horn mouth. The driver is low pass filtered (3d order) and padded about 15 dBs via an autotransformer. Gate duration about 2 ms.

Where did you get the autoformer? And how are they used? I read they can also be used as L-pads.

I would think they introduce typical transformer sounds. I have used an 1:1 isolation-transformer with RCA connections before a tube amp to reduce hum, and it worked, but the high frequencies are somewhat duller.
 
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Where did you get the autoformer? And how are they used? I read they can also be used as L-pads.

I would think they introduce typical transformer sounds. I have used an 1:1 isolation-transformer with RCA connections before a tube amp to reduce hum, and it worked, but the high frequencies are somewhat duller.

I purchased the autoformers from Germany through eBay. I use them as L-pads after the crossover and with a swamping resistor. They have 15 taps and 1.5 dB of attenuation per tap. These are really nice and high frequencies are beautiful IMO.
 

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Hi Gary,

Do you have your design plan published in any way? I mean in terms of crossovers and such. Enough of the pieces has already been written, but I don't recall seeing the whole shebang.

BTW, I grew up in the PNW, mostly in Puyallup. My sister lives in the Portland, OR area and my folks in Chelan, WA, so I am in the PNW a couple times a year.

Josh
 
Yes, definitely worth the effort. Mine are finished too - actually my son's.
Onken / AE TD15M Bass / mid (8 Ohm)
Yamaha JA6681B / AH425 mid (16 Ohm)
Yamaha JA4281B tweeters (16 Ohm)
Cross over: JMLC 3rd order at 900Hz (F3 1026Hz HP, F3 783Hz LP) tailored to driver impedances at 1Khz.
Tweeter 1st order HP at nominal 8K Hz
Set back alignment as per jmlc - adjustable.

Autoformer speaker level inductor wound on 80% Nickel core - on amp outputs before cross over
JA6681B set -12dB
JA4281B set -3dB

It really came together well at the end - I had a lot of doubts it ever would - but the jmlc cross over and autoformer brought it home for me. OK it's all subjective and I cant say I have measured it yet, but it was a good experience doing it over time with my son and really listening together. A good introduction to audio. On SE 300B amps it sounds magnificent. Thanks Lynn.

Total cost inc cross over: A$1600 (all drivers / enclosures etc bought 2nd hand)

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

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


martin
 
Hi Terry,

Already underway, as a matter of fact. First thing was to get my p-p 300B amps going again. They just needed new output tubes, and are now sounding great. I do wish they were quieter, though. Gary Pimm helped me get the Monarchy DAC sounding right again, which also turned out to be a tube problem. Next thing was to install the ortofon SPU that Peter Ledermann rebuilt for me a few years back, which has been sounding quite marvelous in tonight's listening session. Now I am trying to decide on an optimum SUT to match the SPU, in hopes of even better results.

The next DIY project on my horizon will be building Gary Pimm's amplifier design, the Solid-State Tabor (transformer coupled!). Gary brought his amp to my home a couple of months ago and it sounded mighty nice in my system, and nothing at all like any solid-state amp I have ever heard before. The iron for it should be ready by mid-summer.

Gary Dahl
 
Truetone: I have tried L-pads using homemade graphite Duelund resistors and they sound okay but the sound does deteriorate. I am curious about your "Autoformer speaker level inductor wound on 80% Nickel core" and where you found it. All I have seen is Fostex for 8 ohm drivers.

Also, I use bigger horns than you so I will need to look into autoformers for the crossover slopes as well. I can't use too big inductors, because they would ruin too much.
 
Truetone: I have tried L-pads using homemade graphite Duelund resistors and they sound okay but the sound does deteriorate. I am curious about your "Autoformer speaker level inductor wound on 80% Nickel core" and where you found it. All I have seen is Fostex for 8 ohm drivers.

Also, I use bigger horns than you so I will need to look into autoformers for the crossover slopes as well. I can't use too big inductors, because they would ruin too much.

You can get autoformers here: Autotransformers | Critesspeakers.com and here: intact audio among other places.
Also curious why Martin used the autoformers before the crossover and not after.