Why would I not waste the time and money to send a high inductance SPL sub for Klippel testing? Because it has high inductance. I assume you already know the reason since you are associated with Jacob and you just trying to test me.
I think you mean the reverse. Check your facts before you post bile on forums. I design and manufacture low inductance subwoofers for Stereo Integrity, not the other way around.
But anywho I'll try to explain in laymen's terms.
VERY simple concept. A coil is an induction coil exactly like a coil in a crossover network. And what does and induction coil do? it limits highend frequency going to a driver. Same exact thing happens on a transducer however unlike the coil being an air core coil it is turned into an iron core which increases this effect even more. Why is this a bad thing especially in a SPL driver? Simple.
It's a spl driver so you are going to be playing 50, 60, 70 hertz burps or short runs. The I had the SPL coil built as it would handle gobs of thermal abuse however its "crossover" effect brought it down almost 6 db at 70 hertz. How do you test for something like this? Very simple. Burp a sub stage in a vehicle at 70 hertz and measure the output with a term lab. Then put the SPL coil in line with the sub in the vehicle and readjust amp gains (ohm load changed) to achieve same power then remeasure and record results. What you have done in put a filter inline with the driver and measure the high pass roll off that has been caused just like in a crossover used in a set of components. Why does this matter in SPL? Again simple.
Since we now know the SPL coil will be down 6 db at 70 hertz we can figure out how much power needed to achieve the same SPL. Most everyone knows in order to gain 3 db you need to double your input power. Lets say the daily coil will do 150 db on 3,000 watt burp (numbers are arbitrary). Now remember the spl coil is down 6 db at 70 hertz (which is a typical burp realm). This means the spl coil will hit 144 db on the same power at 70 hertz. To get to 147 db (remember on paper you need to double power to gain 3db on paper) the spl coil will need 6,000 watts, and it's still 3 db down. And to get to 150 db it still needs to gain ANOTHER 3db so power needs to be doubled again. So, 12,000 watts is needed just to achieve the same output. Now I'm not a competitor but I'd rather only need 3k versus 12k to achieve the same output.
Yes, Klippel does measure under power and it is called LSI or large signal Identification and it's what I publish as specs. (see Ethos parameters) And you don't NEED to measure with the Klippel to get a ballpark idea of what it will look like if you already know the parameter shifts of your softparts. Fs is gonna go down, Vas is gonna go up, and Q is gonna go up.
You do understand that Patrick Turnmire is the CFO of STEP Technologies which is the company that owns the rights to MMAG? This is the guy I use (along with Enrique) for transducer engineering and Klippel testing. And we can assume you use as he is the ONLY independent lab in the US with a Klippel analyzer. If you use his advise in designing why would my techniques be any different?
I have an advanced FEM program (not FEMM as you two have been referencing during this thread) that shows anticipated T/S's as many variables of subwoofer design are able to be changed/manipulated during the design process...which is the only way to design a driver. If you can not change the Vas of the driver, Cms, etc, while designing, then what good is the program? The linearity (or non-linearity, depending on your market) of the soft parts along with the basic fundamentals of design are pretty important when designing a subwoofer. You can have a cool motor but the rest of the speaker matters a good bit. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif
Basically you spent a lot of time not answering anything. You danced around it[everything] instead.
Can you answer the questions I have been asking this entire time?
1) Can you please publish a full T/S sheet in any form (normal and/or SPL configuration)?
2) When have referred to "motor force" are you referring to BL^2/Re?
3) Re: Question
#2 ; If you are not referring to BL^2/Re, what are you referring to?
Red Rock Acoustics is not the only Klippel in the USA. Since you have stated the latter you are eluding to you having your woofer tested by an additional Klippel-capable party. I don't care who you used. I only want everyone on here to see the results because, obviously, you have Klippel results [you stating that there is more than one person in the USA that can Klippel woofer -
and it is called LSI or large signal Identification and it's what I publish as specs. (see Ethos parameters)
and yet you are, for some odd reason, unwilling to let those results be public. Your SPL figures/estimates stated above are in theory, not reality. I hope your testing shows results close to reality and I hope that you show your results with us.
