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Thread: Woofer size and power usage.

  1. #51
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    Pure :banana::banana::banana::banana:
    heatware chew*
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  2. #52
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    Surprisingly cheap too. $1500 for 10KW, cant complain.
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  3. #53
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    Quote Originally Posted by STEvil View Post
    Surprisingly cheap too. $1500 for 10KW, cant complain.
    Got a break down on the nitty gritty specs?

    Here was the amp's I used to use, mainly chosen so I could compete in a certain wattage class. Cheater amps if you will.

    God I loved those 2 amps. Never caught on fire like Mike's MA's

    http://www.sonicelectronix.com/item_...4KX1200.1.html

    Went through about 8 of em, felt like i was binning cpu's.........in the end we found 2 cherry amps which were capable of running strapped with the MOJO quad 1 ohm wired for 1/4 ohm.

    Mind you they couldn't run this way sustained for very long, just needed them to hold long enough for a burp though. Others we tested couldn't hold the note long enough

    I was running a rack of kinetik's just to feed them, Dual 1/0 runs from the front to feed the rack.

    Eclipse headunit, was the only thing we could find that wouldn't skip installed in the car without having to have a remote station.

    I used a pheonix gold Bass CUBE, for the crossover and cut off, simple but effective.

    I still have my box in the garage, was 4 layer 3/4 MDF all around with the face 6 layer, port is painted pink Lost a bet with the 420 guys once
    Last edited by chew*; 02-21-2011 at 09:54 PM.
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  4. #54
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    Quote Originally Posted by chew* View Post
    Got a break down on the nitty gritty specs?
    http://www.kicker.com/warhorse

    10KW @ 2 ohm
    5KW @ 4 ohm

    ~90% efficiency.

    Still listed on their website as $10,000.. lol

    Here was the amp's I used to use, mainly chosen so I could compete in a certain wattage class. Cheater amps if you will.

    God I loved those 2 amps. Never caught on fire like Mike's MA's

    http://www.sonicelectronix.com/item_...4KX1200.1.html

    Went through about 8 of em, felt like i was binning cpu's.........in the end we found 2 cherry amps which were capable of running strapped with the MOJO quad 1 ohm wired for 1/4 ohm.

    Mind you they couldn't run this way sustained for very long, just needed them to hold long enough for a burp though. Others we tested couldn't hold the note long enough

    I was running a rack of kinetik's just to feed them, Dual 1/0 runs from the front to feed the rack.

    Eclipse headunit, was the only thing we could find that wouldn't skip installed in the car without having to have a remote station.

    I used a pheonix gold Bass CUBE, for the crossover and cut off, simple but effective.

    I still have my box in the garage, was 4 layer 3/4 MDF all around with the face 6 layer, port is painted pink Lost a bet with the 420 guys once
    I've got a ZX750.1 (750 rms @ 2ohm) in my daily ride at the moment. I've run it down to 0.65 ohms and it stood up like a champ other than browning the pair of 40A fuses I put on it in place of the stock 30A's it took. Its one of my favorite little amps, right next to my old Rockford 200a2. Abused the crap out of it and it never gave me a problem

    As to anti-skip with a cd player, just mount it with springs! lol
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  5. #55
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    Quote Originally Posted by STEvil View Post
    Impedance change (rise and dip) are due to excursion. More excursion means more power required.
    Impedance change is due to Inductive Reactance, major rise and dips are because of resonance with driver design/materials and enclosure setups.
    Excursion does not change impedance frequency does, increased volume raises the excursion level but does not change the impedance only the required power demand.

    Smaller speakers are more efficient than larger speakers (free air resonant only), they move less air and have higher power to SPL output.

    Sabrewulf.
    I have just started reading loudspeaker design cookbook by vance, I took a lot of research with me before i went on to reading this. Even studying physics helps.

  6. #56
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    Inductive reactance is a function of current and voltage (and distance and time...) applied to the voice coil. Rise and dip are caused by excursion since excursion changes the applied field strength of the motor structure (via movement and static position in the motor field). As an additional note of interest, I have not researched time (period) as a function of waveform (sine vs square) with fixed power but I suspect it may have further implications on impedance curves.

    Frequency can apply an additional resonant (harmonic) waveform and it is heard (and can be measured) as distortion in actual output. The inductive load that harmonics apply to the coil are actually rather small. At and above the tuning frequency of the enclosure they exist because the helmholtz effect acts as a spring to keep the coil in a normal flux of movement in the magnetic field provided by the motor. Once you get below the tuning frequency of the enclosure excursion increases which allows the field to weaken thanks to the coil leaving the gap further (and for a longer time length).

    Now, thats not to say what is written in the cookbook is wrong, but that current (applied) technology and theory have not progressed when talking coil-propelled drivers.

    The guy I mentioned earlier (Forevrbumpn) has built some really neat prototypes though.. http://www.youtube.com/watch?v=rmRYTQAS7W4


    edit - interesting thought, aluminum inductiveness by movement..
    Last edited by STEvil; 05-04-2013 at 10:38 PM.
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  7. #57
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    Quote Originally Posted by STEvil View Post
    Inductive reactance is a function of current and voltage (and distance and time...) applied to the voice coil. Rise and dip are caused by excursion since excursion changes the applied field strength of the motor structure (via movement and static position in the motor field). As an additional note of interest, I have not researched time (period) as a function of waveform (sine vs square) with fixed power but I suspect it may have further implications on impedance curves.
    As i understand it inductive reactance is a mechanism (might not be the right word) generated within a inductor (coil of wire) that changes it's opposition to current flow proportional to the change of ac current or inductance which is just a increase of current itself i would assume, so i was correct in stating that frequency changes inductive reactance.
    This is what is naturally done with a inductor, how crossover/filters are made and also what makes speakers reactive load transducers. Take away all resonant factors in a speaker coil and you essentially just have a straight forward inductor and will always see a rising impedance proportional to the increase/change of frequency or inductance. The impedance is never linear across the changing properties involved of what i think is called faradays law or whas is lenz law ?. I don't remember or know exactly but they both had something to do with inductive reactance. So coming back to rise and droops i assume they are because again of resonances but explaining how those resonances cause a change in the inductive reactance is exactly what you stated in your previous post about field strength change due to excursion.
    Quote Originally Posted by STEvil View Post
    Frequency can apply an additional resonant (harmonic) waveform and it is heard (and can be measured) as distortion in actual output. The inductive load that harmonics apply to the coil are actually rather small. At and above the tuning frequency of the enclosure they exist because the helmholtz effect acts as a spring to keep the coil in a normal flux of movement in the magnetic field provided by the motor. Once you get below the tuning frequency of the enclosure excursion increases which allows the field to weaken thanks to the coil leaving the gap further (and for a longer time length).
    I am not sure what this is relating too, i can only guess your speaking of the reason resonance with porting causes the effects of impedance change due to the coil leaving the gap more and being less efficient, could this be the reason for impedance dips ?.
    Quote Originally Posted by STEvil View Post
    Now, thats not to say what is written in the cookbook is wrong, but that current (applied) technology and theory have not progressed when talking coil-propelled drivers.
    I have only just started and will expect to reread it.
    Iv only just started lol
    Quote Originally Posted by STEvil View Post
    The guy I mentioned earlier (Forevrbumpn) has built some really neat prototypes though.. http://www.youtube.com/watch?v=rmRYTQAS7W4
    I see your interest in extravagant non high fidelity car audio systems, i assume it's more of a hobby and interest to put your knowledge somewhere rather than pursuing to perfect what you already know. I understand the passion but i do not commit that this type of use with audio technology is for musical enjoyment, its not my cup of tea. But i don't disagree that it is some form of music whether it is misrepresentation of the intended use or not, if people like it then that should not be judged.

    Quote Originally Posted by STEvil View Post
    edit - interesting thought, aluminum inductiveness by movement..
    Not a clue, might look up what your saying later on xD.

  8. #58
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    off to watch iron man 3, will reply when I get back (a little over 3 hours from now probably)..
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  9. #59
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    Quote Originally Posted by STEvil View Post
    off to watch iron man 3, will reply when I get back (a little over 3 hours from now probably)..
    Seen that the other day myself, was quite good considering most part 3 movies can be quite underdone.

  10. #60
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    I was unimpressed by how the extremis bit was incorporated.. Good other than that though.

    As i understand it inductive reactance is a mechanism (might not be the right word) generated within a inductor (coil of wire) that changes it's opposition to current flow proportional to the change of ac current or inductance which is just a increase of current itself i would assume, so i was correct in stating that frequency changes inductive reactance.
    http://www.allaboutcircuits.com/vol_1/chpt_15/1.html

    With current being applied, voltage (frequency) will act as as sine wave if you graph it, when there is no magnetic field present. When the coil is in the gap there is a pre-existing magnetic field which reduces this effect. If the coil is outside of the gap the "sine" wave becomes much more like a square wave since the inductive field being generated is no longer contained. To say that the impedance is changing may be a technical misnomer as you could possibly better characterize it as charge/discharge rates of capacitors.

    Back EMF (Lenz/Faraday's law(s)) is the collapse of the inductor-motor circuit as the coil enters or leaves the magnetic gap, which is time/distance related to the charge/discharge cycle of the coil, which is induced by excursion... Voltage/current are related to the time/excursion since they affected the charge/discharge cycles of the voice coil. Lower frequencies often use more excursion to produce the same output level so the charge/discharge cycle of the coil is lengthened significantly, along with secondary EMF (which can be seen as harmonics).

    My interest in "extravagant" is to improve what exists, unlike what the rest of the industry seems to be doing. The Audio scene has stagnated for the last 50 years
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  11. #61
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    Quote Originally Posted by STEvil View Post
    I was unimpressed by how the extremis bit was incorporated.. Good other than that though.



    http://www.allaboutcircuits.com/vol_1/chpt_15/1.html

    With current being applied, voltage (frequency) will act as as sine wave if you graph it, when there is no magnetic field present. When the coil is in the gap there is a pre-existing magnetic field which reduces this effect. If the coil is outside of the gap the "sine" wave becomes much more like a square wave since the inductive field being generated is no longer contained. To say that the impedance is changing may be a technical misnomer as you could possibly better characterize it as charge/discharge rates of capacitors.
    Ok so the pre-existing magnetic field changes the natural characteristics that a standard inductor would have and thereby changing the overall reactance value over the frequency, i guess that makes sense because a normal inductor is linear across the proportional change of frequency where as the impedance graphs for voice coils is very.. well reactive. I will have to do some research on the square wave relationship and how it affects things, although i am still being beaten by phase relationship of voltage/current. It just beats me to death trying to understand how you get current and voltage at different phases on the same conductor/circuit. I know i am missing something i always do.

    To sum up however frequency does change the impedance (due to reactance) and rise and dips are because of excursion (induced by third party influence like resonance) BUT!, if excursion were the reason for rise and dips. Why is it that when you increase the volume (which increases excursion) that the impedance does not change, because it doesn't. Only changes the power demand required by the amplifier.
    I'm guessing it's because the back emf is not changing due to free space resonance, when the speaker is hitting its Fs area.

    Quote Originally Posted by STEvil View Post
    Back EMF (Lenz/Faraday's law(s)) is the collapse of the inductor-motor circuit as the coil enters or leaves the magnetic gap, which is time/distance related to the charge/discharge cycle of the coil, which is induced by excursion... Voltage/current are related to the time/excursion since they affected the charge/discharge cycles of the voice coil. Lower frequencies often use more excursion to produce the same output level so the charge/discharge cycle of the coil is lengthened significantly, along with secondary EMF (which can be seen as harmonics).
    Ah secondary EMF this is interesting.
    Quote Originally Posted by STEvil View Post
    My interest in "extravagant" is to improve what exists, unlike what the rest of the industry seems to be doing. The Audio scene has stagnated for the last 50 years
    I was going to disagree but then i thought i would reword it, i would'n't say the audio scene has stagnated (claiming all of audio technology) but i would put that statement towards speaker technology only hoping that was what you were referring to. We are still using the same type of speaker technology but only improving on what we have like you said as there is no replacement to superseed voice coil technology. Maybe electrostats but they are problematic i think atm.

    Hey what kind of engineer are you, i remember someone saying you were but i never caught what type. ?
    Last edited by [DANGERDAN]; 05-09-2013 at 08:16 PM.

  12. #62
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    Research AC voltage to understand multi-phase (2,3,6) voltage

    When increasing volume are you using a fixed tone or a varying tone? When you use a fixed tone the system (coil-motor-etc) operates at a steady state which is measured as "unchanged." If you measured from a full uncharged rest to full discharged stop you might see something different though. If you use changing tones (music), transients, and a few other items you will have a large change in the drivers performance. For example with music you could be producing a 60hz tone at one moment then 30hz at the next and could be at any step of power (speaking about subwoofers). This change could happen at any point in the travel of the coil so you may be sending full power to the driver at either an already full field (deep in the magnet) or at nearly when the coil is out of the gap.

    When you think about it, its pure luck that speakers sound as good as they do

    Yes, mostly just speaker technology, though there arent many amp companies pushing to change things. Class J amps are interesting, but technically it takes two of them to be sonically the same as a Class A or A/B amp.

    Not an engineer, that I know of that is.

    edit - Sorry if anything sounds a bit complicated in there, just woke up after over 100 hours work in the last 6 days..
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  13. #63
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    Quote Originally Posted by STEvil View Post
    Research AC voltage to understand multi-phase (2,3,6) voltage
    I actually plan to be a electrician, i have researched all about AC/DC theory, physics, semiconductors, digital theory. Sites like All About Circuits and Lessons In Electric Circuits I have read top to bottom. Also watched all lectures by Richard A. Muller about physics, about 26 lectures in C10 that go for about a hour each. Also lectures from elec 110 and some of elec 120 for electronics by joe Gryniuk from lake washington tech college. On top of that just general research for filling in gaps like this topic we are on .

    You don't know any good websites like i have linked that are any good ?.

    Quote Originally Posted by STEvil View Post
    When increasing volume are you using a fixed tone or a varying tone? When you use a fixed tone the system (coil-motor-etc) operates at a steady state which is measured as "unchanged." If you measured from a full uncharged rest to full discharged stop you might see something different though. If you use changing tones (music), transients, and a few other items you will have a large change in the drivers performance. For example with music you could be producing a 60hz tone at one moment then 30hz at the next and could be at any step of power (speaking about subwoofers). This change could happen at any point in the travel of the coil so you may be sending full power to the driver at either an already full field (deep in the magnet) or at nearly when the coil is out of the gap.
    I am talking about pure sine wave only to keep things simple (sine wave sweeps are mostly used when graphing a impedance plot) but i do understand the complexity's when multiple sound waves are summed together and/or instantaneous frequency change.

    Quote Originally Posted by STEvil View Post
    When you think about it, its pure luck that speakers sound as good as they do
    Quite a lot i have thought that when looking at the research, sometimes you just laugh as to think that if one simple thing was not in existence that speakers would fail to work.

    Quote Originally Posted by STEvil View Post
    Yes, mostly just speaker technology, though there arent many amp companies pushing to change things. Class J amps are interesting, but technically it takes two of them to be sonically the same as a Class A or A/B amp.
    Have not researched other classes yet, i have seen plenty of other patented technology's too though like class Z. Problem with patents though is that it sometimes holds back technology.

    Quote Originally Posted by STEvil View Post
    Not an engineer, that I know of that is.
    Whats your profession if that's ok to ask ?

    Quote Originally Posted by STEvil View Post
    edit - Sorry if anything sounds a bit complicated in there, just woke up after over 100 hours work in the last 6 days..
    Na i understand it pretty well, maybe in the past i was always getting confused, specially when i couldn't grasp impedance a couple years back. But iv come along nicely i think.
    Last edited by [DANGERDAN]; 05-12-2013 at 05:23 PM.

  14. #64
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    No sites off the top of my head, I just tend to stumble around the web reading material as I find it.

    Profession is farming and anything related (welding, class 1 truck driving, agronomy, etc..). Electronics is a surprisingly handy skill to have as well when you need to fix something out in the middle of the field and the boss(es) and repair reps sent from the dealership of the item all dont know how it works, lol.
    Heatware || 01.01.08; AND 111.2%

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  15. #65
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    Quote Originally Posted by STEvil View Post
    No sites off the top of my head, I just tend to stumble around the web reading material as I find it.

    Profession is farming and anything related (welding, class 1 truck driving, agronomy, etc..). Electronics is a surprisingly handy skill to have as well when you need to fix something out in the middle of the field and the boss(es) and repair reps sent from the dealership of the item all dont know how it works, lol.
    Ah really I work/live on a farm also, its a dint of a life sometimes haha.

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