Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?

Ro808

Member
2010-03-27 4:25 pm
It is very possible to cover 50-15k with a fully horn loaded two-way system. I have done many variations on this over the past 25 years. My initial development focus was on the bass horns. These are hyperbolic exponential expansion and the mouths are about 4'X2' and are designed to sit flatly on the floor flare up to take advantage of fraction space loading which improves response. These bass horns fc a little below 50hz and develop ~110dB/w/m. They feature extremely flat frequency response to 500Hz in my untreated listening room. The flat frequency response was achieved by minimizing folds and employing Hyugens wave reflectors. I used a pair of EV15L lead guitar woofers to construct compression drivers for the folded bass horns. The bass horn work is similar to work that has been independently done by Nelson Pass, Bert Doppenberg, Martin Seddon and others. In general, the form of the bass horn looks a lot like a giant vacuum cleaner. My family and friends refer to my bass horns as "The Hoovers". My initial approach for >500Hz were four petal tractix mid and high frequency horns using the JBL 2445 with Radian diaphrams for mids and JBL 2416 drivers for highs. Some years ago, Martin Seddon built a set of AH-160 Le Cleac'h horns in which I have been running Lowther PM2A's. Martin also supplied me with a pair of AH-340's which I'm planning to use with Radian 500-20kHz compression drivers. I could also go to the WE-555 with the larger AH-160. I have adapters for these. I have augmented the bass from time to time with actively crossed subwoofers which seem to work just fine. Generally the bass from the Hoovers is completely satisfying. I use a passive 2nd order Butterworth crossover at 500Hz of my own design. I plan to move to 2nd order Linkwitz-Riley which I am moving to for all passive crossovers. I use tube amps and preamps, most of which I have constructed myself. The horn system I have described is 110dB/W/m. It develops very loud volume with a Decware Zen 2W amp. A 10W 300B really kicks. Bass energy, transient response, midrange clarity, female and male vocals, strings, horns and percussion are thrilling for all genres of music. My thanks to Bruce Edgar for a bundle of papers he sent me, his mentor Paul Voigt, and Bert Doppenberg, and Martin Seddon for months of discussion and friendship.

Some pics, perhaps?
 

camplo

Member
2019-02-25 2:27 am
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Are we not impressed? Pretty straight forward, easy to DIY I would think.... Nothing special going on here? Done before? Didn't the designer just get a patent for this?

My lowly opinion is that it is the best BR ever....not very different from the La Scala
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The front horn of the Jubilee would serve as a wave guide for the bass produced by the BR Ports....while lacking actual loading in the sub area the, the waveguiding should increase directivity would it not?

How does one figure out the Low pass filter affect of the Horn bends? There will be a cancellation based off of the Slot in front he woofers and ports. The Jubilee has slot sin front of the woofers just like the La scala...What for?
 

Ro808

Member
2010-03-27 4:25 pm
Yup those are it, after pulling my drivers I was a fair bit off on the angles of the throat I believe. I have the extra adapters not pictured for the threaded drivers as well. I did however get some measurements, and the horns load the driver below 300hz without any issues. When I'm at my pc I'll try and upload some measurements.

The horns are basically clones of the old (tar-filled) Altec H-1005.

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Several US-designs were licensed to European companies.
Vitavox manufactured its own variant of the Klipschhorn, the CN-157, including a modified, metal version of Paul Klipsch's wooden radial horn.

Vitavox:
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Klipsch:
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Camplo said, "How does one figure out the Low pass filter affect of the Horn bends?"

My approach to this was to minimize and optimize the folds. Many of the folded horn configurations you guys are discussing suffer from ragged FR in the 300-500Hz region. I viewed the bass horn as a waveguide. One of Bruce Edgar's papers, possibly The Show Horn introduced the idea of employing Hyugens wave reflectors. Pull out your physics text and review optics section. I did a lot of things to smooth the "wave guide". Reflections and disturbances are bad, bad! Once you smooth the horn in the 300-500Hz region, proceed normally with your electronic filter design. Divide and conquer baby!
 
Are we not impressed? Pretty straight forward, easy to DIY I would think.... Nothing special going on here? Done before? Didn't the designer just get a patent for this?
No patent for bass reflex combined with horn loading.
The front horn of the Jubilee would serve as a wave guide for the bass produced by the BR Ports....while lacking actual loading in the sub area the, the waveguiding should increase directivity would it not?
The Fb is down in the 25Hz range, the "waveguide" is not large enough to increase directivity much at all for waves 10 times the length of the mouth.
How does one figure out the Low pass filter affect of the Horn bends?
By measuring a straight version and comparing it to the folded version ;)
The Jubilee has slot sin front of the woofers just like the La scala...What for?
Increasing the throat to mouth ratio is good for efficiency, a requirement for a 12" driver to keep up with a horn loaded HF compression driver.
 
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Camplo wrote: "The Jubilee has slot sin front of the woofers just like the La scala...What for?"
So bear with me, I crossed these bridges 25 years ago, so I'm a little foggy. But my recollection is the slots tend to damp resonances and widen midrange dispersion and coupling into the horn mouth. One of the difference between my bass horn design and Martin Seddon's which you showed with the AH-160's is that my bass horns used EV12L drivers in compression enclosures. In my case the 12L's were slot coupled for the above stated reasons. So in addition to minimizing and smoothing the folds with Hyugens wave reflectors, I slot loaded the 12L compression drives to improve mid coupling to the hyperbolic exponential bass horn. This too help smooth the critical 300-500 region simplifying filter design. This may be part of the reason my bass horns have such flat FR. This was my approach, not necessarily the best one.
 
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camplo

Member
2019-02-25 2:27 am
@weltersys
Does compression really increase efficiency or move it from the lower end to the higher end....

The BR section is tuned in the 20's but the front horn has a cutoff much higher.

Doesn't source size have an effect on directivity even in the omni parts of the passband. For example, the direct field will extend farther for a 15" woofer playing the same note as a 6" woofer on the same baffle... while this note is in the area considered omni or larger than either diaphragm
 
Directivity is just a measure of how the horn direct its energy into the environment. As charts below illustrate directivity changes with frequency. Low DI corresponds to wider horizontal or vertical dispersion. High DI here starting at 5khz translates to increased beaming and lobing as frequency moves toward 20kHz. The horn mouth accepts energy from the driver. The horn throat directs energy toward the flare. The flare couples energy into the environment usually in a controlled fashion.

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camplo

Member
2019-02-25 2:27 am
But you probably mean radiation mass/impedance?
Thank you for clearing that up....I am definitely talking about the radiation mass....Larger area of radiation, have larger radiation masses that equate to a higher degree of direct energy to the listening position than a smaller mass.

So with that in mind, I am thinking that the Mouth of the front horn in the Jubilee serves to increase the radiation mass, thus increasing direct energy , also increasing efficiency?

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camplo

Member
2019-02-25 2:27 am
The radiation mass of my horn is larger than my 15" woofer as long as above cutoff I suppose...below cutoff the mass shrinks into the horn.... but what if the driver can keep up pressure without loading? Seems the horn would still maintain the larger radiation mass due to line length and mouth area.

looking at the Jubilee woofer cab... it is sort of like a mass loaded horn once the BR exits into the horn throat. The mass load happens before the line ends, where as a massloaded TL places the mass load at the end of the line... I thought the jbl 238x series to have an effect of lowering cutoff due to a lower csa for the early parts of the throat.

I think mouth size and line depth is a large part of radiation mass/radiation shape and size...I have not fully understood this part of design.

I think the front horn does increase the radiation mass size, compared to the same BR minus front horn at the same spl... but maybe it lowers the efficiency of the low end due to increased path length?

Then again I thought that a larger radiation mass would increase the direct fields reach...

Confusing

Thoughts?
 

Ro808

Member
2010-03-27 4:25 pm
In simple terms, it's about electro-mechanical energy conversion.
Remember, a horn acts like a transformer, converting high-pressure, low-velocity acoustic air movements into low-pressure, high-velocity sound radiation.
That's why you (also) have to take into account the (complex) impedance.

This article explains a few things on the basis of the Klipschhorn.
 

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  • AES-Jubilee_A Revised Low-Frequency Horn of Small Dimensions (Delgado Jr R, Klipsch PW. A).pdf
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