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Engineering Principles

If you are reading this article, you are aware of computer programs that simulate the performance of a speaker driver. In this particular piece we will be discussing the engineering principles that make up an FWA speaker driver and the hard science behind what makes FWA so formidable and acoustically balanced. This piece will not be very popular with most in the industry because it will leave open assumption as to what corners they cut to save money. However, it will explain what makes Funk Audio, FWA, and Harbottle Audio so different.


Basic Engineering.
If you ask an engineer to design something, one of his or her questions will be; “what is the budget?” Well, we actually have removed the accountants from any discussion of our drivers and design, and replaced the build budget with an engineering principal, and then simply priced our product according to what it actually does in real life. Here is a simple comparison that you can do. Simulate our product against any other driver that you think it compares to. Then take the simulated output of our driver and add about 25% from 20 Hz to 60 Hz. Then take the driver that you compared and subtract about 20% of the output over the entire frequency response. That is the real world difference. We offer more usable bass, by vast margins. This test is a rule of thumb and does not apply to all drivers equally, however, the biggest point to take away is this: we design our drivers to exceed simulations by 25% to 30% in key areas and easily hit 100% of theoretical output in long term output. We do this by designing each motor to be it's best at the very edge of it's limit and running hot. It is important to realize that simulations do not account for this engineering standard, neither do Theil Smalls because T/S parameters are an electrical measurement, and the voltages are far too low to push the driver hard and thus account for the effect that thermal changes have on real world performance. You can also see that there is another gaping hole in basing purchasing decisions on simulations alone, because the driver you compared to ours to may not actually hit 100% of its theoretical output before it sounds like it is going to self destruct. On average, we see that the drivers that individuals want to compare our drivers are only capable up about 80% of their theoretical output before there is serious sounds of distress from the driver. In most cases, the driver starts to destabilize at about 70% of the theoretical output, meaning that there is noticeable distortion and noise coming from the mechanical components of the driver. Our drivers are engineered to deliver the exact same high quality sound all the way up to 100% (and more) of their limit with as little sound quality degradation that physics will allow. To accomplish this, every aspect of the driver design affects the end resulted performance:
  • motor shape
  • positioning/orientation of the magnets (this can affect field strength and Bl by as much as 25%)
  • shape,stiffness, and weight of the dust cap
  • quality of the steel in the motor (different rockwell steels have different machining times and can require different tooling)
  • quality of the shorting ring or sleeve material
  • VC material quality
  • CNC machine and tool quality
  • CAD/CAM programming quality (yes you can program machining poorly in the interest of saving time)
  • assembly material quality (epoxies, glue, other consumables)
  • reliability and consistency of the cone and dust cap

When there is a possible difference of 25% to 50% output in real world listening, you have to ask yourself one key question: Why is there such a big gap in performance between brands? And what exactly am I paying for?


Reason 1.
We do not design for output. We design to a specified output and make that output fit our "low distortion low compression" policy and requirements.
​
This is true of all of our product. Our product is designed for sound quality, our motto is Low Distortion and Low Compression. In all truth, we couldn't care less about what a driver can do in theory and how many dB's its throwing around in a computer program. We decide what output we need for an application and do whatever it takes to get there while maintaining our high standards of sound quality that allow it to reliably be used day in day out at any level up to that design specified output level. ​It is this polar opposite philosophy we have that forces us to dial into how good our bass systems sound. Because if you have one driver that sounds really really good regardless of what you throw at it, it will trump the notion of running six drivers that cost 1/8 the price to get the same quality of sound at a specified output level.

This is very different from the general principles many designers work to, being:
  • X value in resources; power/size/funds - what is the maximum peak output we can get. ​
​This policy (which is the exact opposite from ours) fosters little regard for whether that output can be reliably used in end use without objectionable side affects (like distortion) occurring long before that output is realized. 

Why do we design to this policy? The answer lies in what the real world results are when you employ a low distortion and low compression bass system. Simply put, the bass that people hear and enjoy lies around the 30 to 250 Hz range. Low end (30 Hz and lower) is enjoyed by many, however this is the most critical component of distortion, because this is where the driver is moving the most and creating the most harmonic distortion. Low end bass (approximately 0-30 Hz) creates harmonic distortion that is heard and directly affects the mid to upper bass, usually up to 300 Hz or even higher. This is the bass that is easily heard and the bass that gives the low end definition, shape, and context. If your 100 dB output from 80 to 200 Hz has 30% distortion, you are only hearing 70% of the music or film. According to math, this means that 30% of your experience is spent being subconsciously annoyed. I don't know about you, but I have heard and seen people living in construction areas, and the thing that drives everyone nuts is the sound of someone running equipment for hours on end. The punch line is that distortion is not fun for anyone. However, when the same bass is free of distortion and compression, you hear more of what was actually recorded while giving your ears a much needed rest from the harmful effects of distortion, with the added bonus of getting more sound and pleasure from the experience.
​
In order to maintain this standard with integrity, we guarantee that our drivers will never vary more than 1% across performance specifications.
What we need to control this level of commitment to quality is very simple: complete control.
These are the steps that a driver goes through before it is prototyped:
​
1. concept design
  • devise a driver concept complete with:
    • intended use
    • purpose
    • power handling based on purpose use
    • output profile
    • distortion pattern
    • compression pattern
    • and useful frequency response
2. mathematically design and engineering
  • mathematically design the driver according to our principal standard
  • engineer the design to meet our quality control requirements
3. process design
  • design manufacturing processes to complete the driver including;
    • CAD/CAM design and run times
    • source or build CNC machine tooling for processing
    • mould design and build
    • source third party materials
4. develop cost benefit analysis
  • determine if the process is efficient enough to maintain standards


Reason 2.
Quality control through engineering.

Our engineering standard will never be compromised in any way, shape, or form, and to maintain this level of quality in the finished product, we have to build everything in house. Those of you that know Funk Audio since the first conception of their product, know that they did use pretty good equipment sourced from DIY and ODM distributors. But as the reputation for quality grew, the raw ability and performance of standard driver and amplifier equipment became increasingly limited and hard to source, until what was available at the ODM level was just not enough. This facilitated a change and growth that you can clearly see the vast product line that we have today and, in truth, the cost of development by taking our driver designs to off-shore build houses for manufacturing was far higher than buying all the CNC equipment and building the designs ourselves.

The point is that outsourcing to China and other industrialized nations in the interest of cutting costs only created problems for Funk Audio, and eventually the demand for quality could not be met by these build houses or manufacturing facilities. The reason we keep everything in house is because there is no difference in price for us to build it in Canada or in China, when we have set the QC standard so incredibly high. The sad fact is that in order to: hit the same wastage and defect margins that we manufacture to, maintain the same performance variance percentage, and maintain our warranty record of only 2 driver units in the history of Funk Audio ever failing, it is actually far more expensive to build our product overseas when we are faced with the choice of not being able to sell around 20% of the product made or paying significantly more in manufacturing costs. The benefit of keeping everything in house is that we get to control production quality from raw materials to finished product, and this is a verified fact that offshore manufacturing can not keep up with our quality control standards, even when the manufacturing costs are the same. We know, we have priced it all out many times.
​
So what does all of this mean for our clients? You will get what is advertised, and more in raw performance. If you use our product within specifications, there is a very small chance that it will break. And the biggest reason of all, there is literally nothing on the market that can keep up on all performance metrics, and we include distortion and compression in our performance metrics.


Reason 3.
Efficiency is tied to sound quality.

This is a very dense and short paragraph, but it highlights the dramatic affect that our engineering principals have on a “design on paper” vs “the perception of real life performance”.
Efficiency is mostly connected to output and compression. Efficiency can be defined as how much power can you push through your driver while staying cool enough to keep your performance metrics the same. This means that a more efficient design will need less power to get to a user determined output level, meaning less heat generated. Why does heat play a role in efficiency and sound quality? Heat causes compression and some types of distortion, so the less heat you have the better the sound will be with a healthy dose of less power needed to use the entire capability of the speaker driver.

When you take into consideration compression, a more efficient driver will have more output due to less compression. Then as a compounding benefit, often a more efficient design can also handle more power (all things equal) further improving its output beyond what was anticipated. The more maximum output it has due to efficiency, inherently it will have less compression at a lower output levels which directly results in the “musical and effortless bass” qualities that FWA is known for. So in itself, efficiency is just one of many “sound quality” determining factors, and if all things equal, our drivers are engineered to be more efficient and so they are better at handling a wider range of bass and by default they can handle more power and exceed simulation output levels. How many other drivers fall into this category?


Reason 4.
Quality control.

I touched on quality control (QC) earlier, but it deserves a spot of its own. FWA and Harbottle put huge emphasis on QC, to the point where we have actually devised specific testing that goes far beyond what the industry considers as standard in both performance and QC. How does QC affect performance? The quality of metal used in the motors, the precision tolerances that it is machined to, the consistency of the machines doing the work, the quality and maintenance of the cutting tools and CNC equipment, and the people handling the parts make the difference in the end performance results. These are common corners cut in manufacturing that add to the bottom line of the manufacturer. And there is nothing wrong with that if QC is not the priority. You see, we don't want to deal with warranty, we don't want a customer to come back to us after a few years and say “it's broken”. We would rather build it really well, design it so it's really hard to blow up, and make it so it will last a really long time so we don't have to mess around with broken stuff later on. We are kind of lazy that way.

As mentioned before, our designs are manufactured to a 1% variance in performance. To get the same guarantee from any off-shore manufacturer would cost so much more it is, in reality, cheaper to keep all the machining and manufacturing in house. The hard reality is that it is very difficult to get a off-shore manufacturer to commit to that kind of QC, actually its next to impossible but we do have one in the wings if we ever need it. Here is where it comes down to numbers. The designs that we build are over engineered by a hefty margin. This allows us to exceed simulation performance. However, this presents another problem, they can never be cheap to build even if we build thousands at a time. Each and every part and measurement is calculated to reinforce the standard that we set so our drivers are the best they could ever be. If we were to compromise in the slightest way to save time or money, the driver could never deliver what we guarantee.

That, my friends, is what you buy at Harbottle Audio and FWA. Engineered Quality.



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Harbottle Audio
​Copyright  © 2015
  • Main
  • About
  • Product
    • Car Audio Index
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    • Product Type >
      • Audio Management >
        • ASP-2M6
        • ASP-4M8
      • Amplifiers >
        • Harbottle Audio Rack Amplifiers
        • FWA Plate Amplifiers >
          • 0.5kWx2M1
          • 2.4kWx1M3
          • 2.4kWx2M3
        • ALLDSP Rack Amplifiers >
          • SMA-4P0808
          • SMA-4P2408
          • SMA-6P2408
      • Speaker Drivers by Series >
        • Xcursion Series >
          • vX
          • vXR - Reference Edition
        • Studio Series >
          • High Frequency
          • Midbass
          • Subwoofers
        • Reference Series >
          • High Frequency
        • Ultra Series >
          • High Frequency
          • Subwoofers
        • Elite Series
      • Enclosures >
        • Man18A
        • Man18S
        • Man18B
      • Passive Radiator >
        • PR18v1
    • Custom Color >
      • Color
    • Merchandise
  • Services
    • Design and Prototype
    • ODM
    • OEM
    • Pro Audio Systems
    • Bespoke Audio
  • Information
    • Bass Detail
    • Engineering Principles
    • Design Standards
    • Speaker Enclosures
    • Dealer Application
    • Reading Test Results
    • Payment and Currency
    • Policies & Shipping
    • Warranty
    • Dealer List
  • Opportunities
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  • Contact
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