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Hartke Drivers - materials , shape or magic?


funkydoug
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Hi, 

I've been curious about this for a while so thought I'd ask the collective BC brain ... why are Hartke cabs thought of as having 'edge', 'zing', 'cut-through' ?

 

Thoughts:

- They are at least part aluminium. Can't be that, visually shiny metal doesn't produce audibly shiny sound?? This is surely visual bias / marketing talk, no?

- they have a different shape to 'regular' drivers. Does central part of the cone act as some kind of whizzer / HF dispersion device?

-  maybe they just sound the same as any other speaker, but people hear with their eyes?

Any thoughts?

Cheers, Doug

 

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The central part of the cone is really important. Different size, shape etc all affect dispersion. Different studio monitors and high end hifi have many different designs because of it.

 

I suspect that the alu cones have a particular tone because of their rigidity rather than necessarily what they are made from.

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It's mostly confirmation bias. If you think a speaker will sound a particular way it will. Seeing an aluminum cone the natural assumption is that it will have a brighter sound than pulp, so it does. Going to an aluminum cone was a stroke of marketing genius on Hartke's part, as it separated them from the rest of the pack. The same applies to Markbass. There's nothing special about their drivers, but the yellow cones would lead one to think that they're somehow different.

 

Confirmation bias in audio is pervasive; even those who you'd think would be immune to it are not. That's why good engineers never trust what they think they hear without confirming it with measurements. So are Hartke brighter? I don't know. I've never seen them measured.

http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html

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7 hours ago, funkydoug said:

- They are at least part aluminium. Can't be that, visually shiny metal doesn't produce audibly shiny sound?? This is surely visual bias / marketing talk, no?

 

Aluminum cones are used quite a bit for hi-fi. The principle benefit is rigidity: they flex less than most other materials, which results in lower distortion. The principle limitation is that they lack the internal damping of softer materials like pulp or polypropylene.  While all cones exhibit break-up at high frequencies, softer cone materials tend to spread the break-up across a range of frequencies, while aluminium and other stiff cones like carbon fibre ring like a bell at a single frequency. The frequency peak can easily be 10dB and getting it under control needs heavy filtering.

 

I'd guess what you're hearing when you listen to Hartke drivers is the ringing and distortion inherent to all aluminium cone drivers.

 

This is the frequency response of a high-quality 10" aluminium cone driver:

f_seas_excel_loudspeaker_woofer_e0026_w2

Edited by stevie
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There was a test in an acoustic lab, when I studied, so this was long ago. There was a set of hifi stuff, one CD, and three sets of speaker grilles: black, brown, and white. The listeners had a short break between "changing speakers", while only the grilles were changed.

 

Guess what? White was slightly aggressive, brown pretty dull, and black most balanced.

 

Aluminium! Shiny aluminium! Therefore Hartke has to be aggressive, and what were their words in the advertisements? Transient attack!

(The question remains, what does it mean?)

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21 hours ago, funkydoug said:

Does central part of the cone act as some kind of whizzer / HF dispersion device?

All cone loudspeakers flex at high frequencies and adding a second whizzer cone to boost the highs was a common trick back in the 70's when a lot of PA speakers lacked horns and a crossover. There are still a few manufacturers making "full range" 12" drivers such as this

image.png.12451c10c6b37c0256bf052e14459e4f.png

The use of Aluminium in speaker cones has a long history, as @stevie has said and the characteristics are well known: stiffer than most fibre cones, poor damping of cone resonance and very pronounced breakup modes at high power and frequencies. Often aluminum was used with other materials to damp the resonances or to further stiffen the cone to get pistonic movement. There was even a craze for DIYers to add aluminium foil to their hi fi speakers at one point :) For pulp cones there is a lot of careful mixing of different plant fibres to get the right mixture of stiffness and self damping of resonance so people who design the drive units can to an extent control the way the cone behaves under breakup. I can remember one speaker that used banana fibres in the mix.

 

I can't believe the people who came up with Hartke's signature gimmick weren't aware of this, or of it's marketing potential. Given the involvement of Larry Hartke I'd imagine a lot of this would simply be him asking for a 'bit more of a brighter tone' and then picking something that sounded good to him after a few iterations. They wouldn't have been looking for a flat response, just something that sounded good and would sell well. I quite liked my Hartke

Edited by Phil Starr
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There is likely some science behind why they sound a little, umm, different, but for now, let's dispense with that.  I moved from Ashdown to Hartke when I got my endorsement with them.

 

When all this was fields, I used some of the cabs with the original aluminium coned units.  To my ears they were very bright compared to my SWR/Trace cabs I was running at that point; same amp setup/settings.  They just seemed to pick up every nuance of what the bass produced.

 

When I got my endorsement, I decided to go with Hydrives; I'd been running Ashdown ABM and MAG enclosures and these also sounded quite muddy compared to the Hydrives.  One thing I would say without hesitation is that the switchable HF driver/horn adds significantly to the tone.

 

Interestingly, I won Alex Claber's prototype Big One (the first ever Barefaced, apparently) at one of the SE Bashes; I was gigging that night in Basingstoke and used the Big One.  I never used the Hartke stuff again in anger and let my endorsement lapse.  

 

 

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Something to consider is if aluminum was intrinsically superior why didn't the industry shift to it en masse? There are two reasons. One is that it's not superior. There are many materials that work well for driver cones. Aluminum is merely one of them. Every speaker manufacturer with any interest in it would have obtained free samples from driver manufacturers to find out for themselves if there was good reason to make the change. It would seem that they did not.

 

Second is that none of them would want to be seen as copying Hartke, in so doing tacitly acknowledging that Hartke was better.

 

There are a number of ways to configure drivers to give different results. Using aluminum cones is one of them, but hardly the only one, nor is aluminum used exclusively to realize better high frequency response. If that was the case why does this subwoofer driver have an aluminum cone? https://www.parts-express.com/Peerless-XXLS-P835016-10-Black-Aluminum-Cone-Subwoofer-4-Ohm-264-1648?quantity=100

 

Lastly, while Hartke seems to be the only major player that uses aluminum cones for electric bass, they're quite common in the hi-fi world. We're usually unaware of it, as most of them are painted black.

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I'd wager that a major reason for using aluminium cones is cost. Alu' is easy to form into shapes, can be made to have consistent thickness across something of any size and shape and is cheap and readily available.

 

There is relatively limited use of pure aluminium. It's not strong or rigid in raw form and prone to fatiguing. Consequently it's often blended with other metals to create alloys to make it suitable for its intended use. You'll see aluminium described as being of 1000 - 8000 type. The number denotes what other metals it's blended with. 1000 is pure alu', 2000 has added copper, 3000 manganese, and so on (Google something like "types of aluminium" and you'll discover what they are).

 

1000 is very conductive, so is typically used for electrical transmission. Being cheap, it's also used to wrap foodstuffs. 2000 alloys can be heat treated to increase strength whilst retaining lightness and so are used in things like aerospace. 3000 is easy to weld, so is used for cookware, roofing and flooring, etc.

 

I wonder which alloy is used/best for speaker cones. Now there's another rabbit hole for audiophiles to dive into 🙂

 

Edited by Dan Dare
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