104 db / watt
400 W AES
copper demodulation ring
https://www.eighteensound.it/en/products/lf-driver/8-0/8/8nm610 8ohm
does it get any better ?
looking to cover about 250 hz to 1 khz
here is what it looks like inside:
400 W AES
copper demodulation ring
https://www.eighteensound.it/en/products/lf-driver/8-0/8/8nm610 8ohm
does it get any better ?
looking to cover about 250 hz to 1 khz
here is what it looks like inside:
It depends on the application. Horn loaded, it sure looks nice. 250 Hz requires quite a horn though for it to load properly. It is really well behaved with nice frequency response. Simulation?
i wouldn't horn load it just apply lots of DSP boost to lift the low end.
it wouldn't overheat the driver or amp since the impedance at those frequencies is very high so barely any current would flow.
these low Q drivers are actually most efficient at the very frequencies at which they lack output.
This won't do 250, even horn loaded, judging from the spec sheet. It is about 12 dB down at 250. Compensating this with drive level requires 16 times the power.
How do you get extra voltage without extra power? I understand your concept about efficiency though. My take on it was that if it took 2 watts to drive that frequency it would still only take 32 to drive it if it were 16x more power.
But my niavity in voltage in amps makes your statement hard to understand, how does the amp know to only push more voltage and not more amps?
Can you break that down? I thought amps had fixed voltage rails, unless it was a class h or t. Is there something about it being 100 hz that makes the voltage go up and not the amperage?
i mean compared to a similar driver with a higher Q it will actually take less power but more voltage to drive to same level at 250 hz.
most people if they wanted to hit 250 hz would choose a different driver that was simply flat to 250 hz ... but that other driver would be about 10db less efficient overall and have half the impedance at those frequencies and actually pull several times more power for same output despite not requiring any "boost" ...
So… back to the point about the amp knowing to increase volts only? Is that a thing or are we stuck in theoryland?
Also, what is so special about 250hz?
Also, what is so special about 250hz?
I was inprecise. The driver is not quite 100 Ohms at resonance though, rather like 45. And at resonance, distortion tends to shoot up.
If the impedance is higher at any frequency due to resonance, it makes sense that the same relative amount of increased distortion will be present. I don't think it is true that this rise in impedance equal "free" extra output as you suggest. My guess is that you will see massive power compression if you try to boost that much at 300hz at those levels.
Axi is correct regarding the higher efficiency and less power needed. However, some serious voltage swing is needed to fully utlize the driver potential. A less efficient driver may ironically need less voltage for the same acoustic output.
The very low q driver is far less sensitive to distortion rise around Fs than high Q dito due to its strong motor.
The main drawback with varying impedance is varying power compression with frequency. See some power compression measurements of bass boxes for example. The ideal would be constant impedance in the band pass. All frequences would then be attenuated equally when power rises.
The very low q driver is far less sensitive to distortion rise around Fs than high Q dito due to its strong motor.
The main drawback with varying impedance is varying power compression with frequency. See some power compression measurements of bass boxes for example. The ideal would be constant impedance in the band pass. All frequences would then be attenuated equally when power rises.
It would be an unusual amplifier to deliver hundreds of watts into a 45 ohm (or 100 ohm, depending on who we believe)... As Petter Persson say "some serious voltage swing"....
Most of the comments can't see the forest for the trees.
This midrange is intended for (big) horn application from 500 to 3000Hz, or direct radiating from 800 to 4000Hz (see the frequency responses in the datasheet).
It may be equalized for direct radiation with +10dB boost at 450 Hz, which brings flat response from about 400Hz to 4000Hz. But in that case, it need powerful amplifier with high voltage swing (and steep active high-pass filter at about 350-400Hz). Because on the market there are no amplifiers with high voltage swing and low amperage capacity (i.e. amps optimized for 12-30 ohm load), you must use the existing conventional, powerful and expensive amplifiers with high voltage swing and high amperage capacity (for 4-8 ohms load) - which makes the +10dB boost very debatable and moot.
This midrange is intended for (big) horn application from 500 to 3000Hz, or direct radiating from 800 to 4000Hz (see the frequency responses in the datasheet).
It may be equalized for direct radiation with +10dB boost at 450 Hz, which brings flat response from about 400Hz to 4000Hz. But in that case, it need powerful amplifier with high voltage swing (and steep active high-pass filter at about 350-400Hz). Because on the market there are no amplifiers with high voltage swing and low amperage capacity (i.e. amps optimized for 12-30 ohm load), you must use the existing conventional, powerful and expensive amplifiers with high voltage swing and high amperage capacity (for 4-8 ohms load) - which makes the +10dB boost very debatable and moot.
distortion is due to displacement not impedance.
impedance has 3 parts:
1 - resistive ( complete waste goes straight into heat )
2 - inductance ( doesn't go into heat but makes amplifier fight ghosts )
3 - back EMF ( present at all frequencies but more prominent at resonance )
back EMF is what you want. any power that goes to overcome back EMF is going into movement of the cone. this driver's impedance here is dominated by back EMF and that's why it is so efficient and such a high end driver.
i guess impedance that has so much slope to it will have a profound effect on frequency response as the coil heats up ...
but in this case the coil would be kept fairly cool due to 3" inside/outside coil, aluminum bucket enclosure and 400W AES power handling ...
what makes this driver attractive to me is actually how cool it will run for any given output level ...
100% ...
the applications you describe is where the driver would really shine - this is evident from the datasheet measurement graphs.
unfortunately i simply do not need anything above 1 khz because i want to use a compression midrange capable of going down to 400 hz ABOVE this driver in frequency range.
at first i dismissed these cone midranges completely because they cover essentially the same range of 400 hz - 4 khz as my compression midrange would ... but then i read that paper midranges sound better than compression midranges ...
but you have to consider that a compression midrange would have perfect dispersion at 4 khz whereas this cone would not ... on the other hand while a compression mid could reproduce 400 hz distortion might be high whereas i can array this midrange and lower distortion that way.
but yes generally speaking this 8" sealed back paper cone covers essentially same frequency range as something like BMS 4592 ND-MID or BMS 4594 ND-MID or BMS 4599 ...
i realize this is getting ridiculous from the perspective that less is more ... i know you can just build a 2-way that would work really well ... you can also just buy one.
i want a system unlike what anybody has or ever had. the very first speaker i built in high school had a 2" dome midrange ( 650 hz - 3 khz ), but that wasn't unusual enough for me. so i then built a car audio system with 1.5" dome mid-tweeter ( 1.5 khz - 7 khz ) ... it worked great but more importantly in the 15 years since i have NEVER heard of anybody running a car audio system with a 1.5" Scan-Speak dome mid-tweeter crossed to a Beyma AST-05 Supertweeter ... i don't have that car anymore but i still have those drivers in the basement and they remind me that i had one of the most unique and interesting setups and how i used to terrorize people with those bullet supertweeters ...
let's face it a lot of the systems people are building such as transmission line loaded fullrange drivers driven by vacuum tube amps running off a a vinyl record player - don't make any logical sense. these people just want something interesting that has performance they find acceptable.
although i would NOT find the performance of their systems acceptable to me personally at least i'm reading about their systems online ... whereas if somebody just goes to Best Buy and picks up some Bowers & Wilkins yes they will almost certainly work better but good luck telling anybody about your Bowers & Wilkins speakers - nobody cares. The Harman Kardon system in my car works better than the system i built 15 years ago - yet i don't get to tell anybody about it because millions have very similar systems in their cars.
actually pop music is quite good. it is produced and mastered by very skilled people. but you can never take pride in listening to something that plays on the radio because everybody does that.
DIY is about blending engineering and art. Most of you are good at one or the other - you can build a system that works well or a system that is unique. BUT NOT BOTH.
I want a system that is both, because i'm better than everybody and my system has to reflect that.
🙂
reminds me of what somebody said on Twitter ... it went something like " oh you read a book you're proud of that ? but you didn't WRITE it ... "
buying a speaker is like reading a book ...
building one is like writing it ...
i am not going to write a book that's a copy of somebody else's book - you can stop begging me to do it - it's not going to happen.
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