What is special about horn loaded drivers?

[Steve81]

I think I will wait for the powered versions, which I hope are in the works. Powered loudspeakers, or those with dedicated electronics are so sensible.

What can I say, in my ideal world, someone would come up with a standardized format to deliver digital data and AC power to a speaker in a single cable, similar to how HD-Base T can deliver an A/V signal to a TV and power it over a single Ethernet cable. At that point, you just need a pre/pro to send the data and act as a power distribution hub. Barring that, I don't see active speakers really taking off in a domestic environment where power outlets aren't necessarily placed in a way conducive to setting up 5+ channels of powered speakers.

But then what would the audio journalists have to talk about? Wires? Spikes?

Cowbell. We need more of it.

 

[TLS Guy]

The distinction between pro monitors and consumer speakers is (a) color: black (b) high reliability: down time in a studio is expensive (c) quality control: they all must be as nearly as possible the same (d) output: recording engineers have a "deaf" wish. There is no difference in the sound - the performance target is the same (the "circle of confusion" for those of you who have read my stuff). Part of the cost of a pro product, and also of some high-end consumer speakers is the additional cost of end-of-line quality control and adjustment if necessary. Most products simply go into boxes and the consumer is the QA department.

With the M2 and the new smaller, more affordable 7 series (http://www.jblpro.com/www/products/recording-broadcast/7-series#.VuL2mMf5jww
there is dedicated electronics with equalization based on anechoic measurements. The M2s are spectacular, large, heavy and expensive, but the essential design elements are in the 7 series. Although I "lust" after the M2s, they are not very practical for my HT. The 7 series sound just as good, and play plenty loud for a HT. No sculpted, hand polished rosewood though :-(

If you think that M2s are "efficient", consider that they are delivered with a 1 kW power amp for the woofer and the same for the horn + DSP. The horn driver is 20 ohms so it really needs the voltage swing, not the current. But in a typical HT much less power would do the job.

And, yes, the difference between them and cone/domes is that there is no discernible power compression at high sound levels. The high level distortions in horns of yesteryear (still on the market) have been substantially reduced by better throat designs. The new, better, compression drivers do not use metal, much less beryllium, diaphragms. And they go to 20 kHz. I love science!

I think I will wait for the powered versions, which I hope are in the works. Powered loudspeakers, or those with dedicated electronics are so sensible. The only reason for those monster monoblock arc-welder power amps is to drive high-end loudspeakers that are incompetently designed and have impedances that drop to 2 ohms or less. When the power amps are matched to the transducers, everything is smaller, cheaper and better, and electronic crossovers beat passive ones any day.

But then what would the audio journalists have to talk about? Wires? Spikes?

What a welcome and timely post!

I have been harping away here advocating the ditching of passive crossover for years here, especially for low frequency passive crossovers.

I also concur that most of those exotic three and four way speakers are incompetently designed.

I am encouraged that you feel these new horns are ready for prime time. I have to say I have a degree of skepticism. I will have to seek them out and try to give them a fair audition.

Efficiency/sensitivity is an important issue. A VC gap is not an auspicious place to be dumping lots of power, especially at high current. Nor are the inductors of passive crossovers a good conduit for high currents. Dynamic thermal compression is a very significant issue in loudspeakers, especially high powered ones.

I loved your home set up for its elegance. I am fortunate to have a dedicated HT room and have room for large speakers.

Each speaker is driven from three amps delivering a total of 750 watts to each speaker. They are dual aperiodically damped dual transmission lines, tuned one half octave apart. The lines are damped just to the point were there is only one peak of impedance. Both lower drivers play below 60 Hz, but the upper driver has the equalized BSC signal for the upper drivers as well to off load them. The LFE signal is captured, but I can flick from the pre/pro bass management to mine at the flick of a switch.

Crossovers are active except the tweeter crossover. I have trouble with the concept of providing a power amp for tweeters. I frequently ponder doing so, but they sound so good. F3 at that location is 20 Hz. They certainly can shake the floor and your body cavities.

I installed those speakers at that location in April 2006. I have been very pleased with thee results to say the least.

The center speaker is a TL with a coaxial design. The surrounds are 2.5 way sealed. The rear backs are also dual TLs with the lower 180 Hz crossover active. They started life in 1984.

 

[Steve81]

I installed those speakers at that location in April 2016. I have been very pleased with thee results to say the least.

That reminds me, can I borrow the DeLorean for a few errands sometime?

 

[TLS Guy]

That reminds me, can I borrow the DeLorean for a few errands sometime?

I made a typo! The speakers were finished and installed April 2006.

I don't have a DeLorean, so you might have to make do with the 1948 Willys CJ 2A.

Or the 1988 Suburban 6.2 Lt Diesel. I have preserved the family wagon.

Any of those fit the bill?

 

[Swerd]

But then what would the audio journalists have to talk about? Wires? Spikes?

I'm holding out for oxygen-free carpet spikes.

 

[Steve81]

Any of those fit the bill?

Sadly no. I was hoping for something like this:

 

[Swerd]

Sadly no. I was hoping for something like this:
View attachment 17767

With the right sized flux capacitor, that 'sleek-as-a-greyhound' 1988 Suburban could do the job.

It's the right vintage .

 

[Defcon]

You guys are forgetting a crucial detail - you'd still need a monster monolithic amp to provide the 1.2 GIGAWATTS

Like 10 of these -

(http://luxurylaunches.com/gadgets/most-expensive-amplifier.php)

That M2 is starting to look pretty cheap !

 

[Floyd Toole]

This is amazing, Deacon. I suppose it is sacririgious to ask "why"? If you believe in "headroom" maybe, but the only headroom I have faith in is related to my hats

Is this an early April Fools joke?

 

[highfigh]

I made a typo! The speakers were finished and installed April 2006.

I don't have a DeLorean, so you might have to make do with the 1948 Willys CJ 2A.

Or the 1988 Suburban 6.2 Lt Diesel. I have preserved the family wagon.

Any of those fit the bill?

They need flames.

 

[highfigh]

I'm holding out for oxygen-free carpet spikes.

I want Oxygen free carpet tacks.

I went to see one of my reps and once again, I marveled at his speaker cable supports. We discussed some of the things that I think are ridiculous and he just kept saying "It's experiential". He's in the "I never really heard my system until I got the new power cords" crowd. Told me the amps really open up in about 20 minutes, now- used to take hours.

 

[Defcon]

This is amazing, Deacon. I suppose it is sacririgious to ask "why"? If you believe in "headroom" maybe, but the only headroom I have faith in is related to my hats

Is this an early April Fools joke?

Is there ever a good answer to many of the choices in high end audio? At that point I believe it becomes rather closer to religion than science and sanity does not prevail. I wish it was a joke but there are plenty of companies selling exotic insanely priced audio gear as I'm sure you know about more than most.

 

[shadyJ]

Is there ever a good answer to many of the choices in high end audio? At that point I believe it becomes rather closer to religion than science and sanity does not prevail. I wish it was a joke but there are plenty of companies selling exotic insanely priced audio gear as I'm sure you know about more than most.

Seems to me that performance is secondary in many of these cases. They are just status symbols, and claims of performance advantages are merely thin justification for these extravagant displays. I am not sure if many of the owners actually believe there is a performance difference, but more than that, I doubt they would care either way, since its all for the sake of appearances.

 

[highfigh]

Seems to me that performance is secondary in many of these cases. They are just status symbols, and claims of performance advantages are merely thin justification for these extravagant displays. I am not sure if many of the owners actually believe there is a performance difference, but more than that, I doubt they would care either way, since its all for the sake of appearances.

I don't think we need to go back to plain stamped steel cases but some of this stuff concentrates on cosmetics too much to be affordable. People need to realize that speakers have largely become 'furniture'. Lots of pretty boxes that make sound, but many aren't particularly good. How much of the Wilson speakers' (or any brand that makes the 'Most Expensive Speakers' list) price is really about sound? How about amplifiers and preamps? How many are more jewelry than electronics?

 

[tom67]

Invariably, what is missing from horn discussions is the horn. Over the years I can't help but notice that there is a blind assumption, especially from the horn detractors. The assumption is that horns are metallic cones where the diaphragm is buried a foot deep in the throat, much like public address models in the 1950s. If you look at products from Klipsch, HSU, JBL etal, most would best be described as "vestigial horns", and have been so for many decades. The diaphragm is sunk about an inch below the baffle. Further, the horn itself is generally a composite material with a better damping factor. Frankly, the conventional tweeter on my Q series kef models is sunk almost as deeply as the the Klipsch and embedded in the larger driver which would have a horn effect. Other conventional tweeters are recessed to varying degrees. My point here is that most of these discussion may be about older horn designs that really don't exist much in the present market place.

 

[Floyd Toole]

tom67: you are right about a lot of "horns" these days. A classic horn is driven by a compression driver feeding the throat through a phasing plug in an attempt to create a plane wave at the throat of the horn. That wave then expands through the horn radiating a shaped wavefront into space - this is the designed-in directivity. In theory it should apply to all frequencies radiated by the horn, but when wavelengths are small compared to horn dimensions things come unstuck. The long throats of classic horns were the origin of much distortion and distinctive sound - all unpleasant.

New horns tend to have short throats, novel expansion contours, and shaped surfaces to generate better control over the radiated sound in more than just the horizontal and vertical planes. That comes from elaborate computer modeling and much trial and error with 3D printed prototypes, all of which did not exist until recently, and even now are not affordable by everyone. Then one needs comprehensive anechoic data to confirm that it works.

A lot of designs nowadays are a combination of horn/waveguide loading at lower frequencies and direct radiation at higher frequencies. Then all bets are off, but there are some examples that work well. The "old days" can still be seen in some present day products, but there are some fine examples of progress. Twenty years ago I thought i disliked horns for high-quality sound reproduction. I have changed my mind. I wasn't wrong, but science got involved and made things better.

 

[Defcon]

tom67: you are right about a lot of "horns" these days. A classic horn is driven by a compression driver feeding the throat through a phasing plug in an attempt to create a plane wave at the throat of the horn. That wave then expands through the horn radiating a shaped wavefront into space - this is the designed-in directivity. In theory it should apply to all frequencies radiated by the horn, but when wavelengths are small compared to horn dimensions things come unstuck. The long throats of classic horns were the origin of much distortion and distinctive sound - all unpleasant.

New horns tend to have short throats, novel expansion contours, and shaped surfaces to generate better control over the radiated sound in more than just the horizontal and vertical planes. That comes from elaborate computer modeling and much trial and error with 3D printed prototypes, all of which did not exist until recently, and even now are not affordable by everyone. Then one needs comprehensive anechoic data to confirm that it works.

A lot of designs nowadays are a combination of horn/waveguide loading at lower frequencies and direct radiation at higher frequencies. Then all bets are off, but there are some examples that work well. The "old days" can still be seen in some present day products, but there are some fine examples of progress. Twenty years ago I thought i disliked horns for high-quality sound reproduction. I have changed my mind. I wasn't wrong, but science got involved and made things better.

Great post. The more I read about this, the more I'm surprised how the shape of a waveguide (which can be a $5 plastic part) can have such a profound impact. This is why we see exotic shapes like in the M2 or the SEOS waveguide (though I don't know if that is backed by actual research) done by the DIY people.

It seems to be there are no real downsides to a good horn design - you get much higher efficiency and the dispersion pattern can be controlled via waveguide shape.

 

[Defcon]

I don't think we need to go back to plain stamped steel cases but some of this stuff concentrates on cosmetics too much to be affordable. People need to realize that speakers have largely become 'furniture'. Lots of pretty boxes that make sound, but many aren't particularly good. How much of the Wilson speakers' (or any brand that makes the 'Most Expensive Speakers' list) price is really about sound? How about amplifiers and preamps? How many are more jewelry than electronics?

What's funny is that the people who actually are responsible for content creation, the sound designers and mixers, use none of the audiophile gear and would laugh at it. They use pro monitors and pro amps.

I suppose its not very easy to sell snake oil to professionals

 

[Floyd Toole]

Defcon, I wish what you say about pros not buying snake oil was true. It turns out that they are as susceptible to a good story line as consumers. After all recording engineers are "artists", not technical engineers - although a few are both. Over the years they have been sucked into silliness like the Auratone, NS-10, UREI 811,12,13 mediocrity, and some studios still proudly proclaim that these are still in use. You will find measurements on these and others in my book - Figure 2.6 and Chapter 18. Others follow the high-end audiophiles down the path of gloss and semi-science. B&W 800s are proudly shown in Abbey Road and the Lucasfilm scoring studio, and I have seen them in lot of other places. Many mastering engineers use consumer loudspeakers. Not all of these are state-of-the-art by any means. But now, the best pro loudspeakers sound like the best consumer loudspeakers - neutral - that is as it should be.

As I conclude in my McGill university lecture on YouTube, nowadays monitor loudspeakers must be neutral, so that they do not become part of the recorded art. I want a chance to hear what was created, not an adulterated version.

 

[tom67]

So perhaps there's little need for further argument over classical horn designs since they really don't exist in the marketplace anymore. what you're actually seeing in Klipsch and other brands that have any real sales volume are vestigial horns that really differ little from the conventional tweeters on most models