Moving Coil vs. Linear Drive Speakers with Dave Rat 

Same thing I said when I saw it. Amazing!

Me too, brother! Oh, and I am a drummer, too!

I guess you wouldn't want them to "kick" in at any threshold with a super loud volume because that wouldn't sound great. They will take over from the next cabinet above (in the frequency spectrum) and just extend the response down to lower frequencies at the same level.

I think this speaker produce Voice not music?

@@sekng473 I thought it was a low frequency bass driver? I could be wrong tho.

2 speakers out of phase: Such a simple wiring mistake. A monumentally horrible effect on the sound, with such an easy corrective measure to fix it.

Yes 2 units in series is 0.5ohm and 20k so there is amps out ther that can do it. Unfortunately this design has only very limited xcursion compared to traditional spl speakers

​@@bassdaboband here I thought space and rear suspension would be what limited the use of 2 of these. 😂😂😂

@@jasonnelson6624check the parameters. Those woofers play well in 250liters each

I'd suspect the motor noise may be a non-starter for car audio.

@@FOH3663 I had wondered if an ib setup would help with that?

Im trying to learn more about Linear Drives but I cant seem to search good results. Where do you get info about them?

​@@pacresfrancis1565 I'd peruse Voice Coil, an industry source on drivers. ProSoundWeb as well.

Big problem with these are very high Q of the system. Your frequency response changes with just about everything: sub position, number of subs, temperature, drive level...basically they never sound the same. And also motor can overheat pretty easy. And glide rails fail.

@@Sheldon42where does this information come from?

@@bassdabob I developed and built Mforce subs. So, first hand. You need to correct EQ on them every time you use them.

⁠@@Sheldon42so position and amount is similar to other systems? Temperature? You mean the surrounder temp? I could not notice any further heat until now. I believe glides might fail because they can easily be dirtet. Maybee we speak separately about your experiences.

Yes. A rotary subwoofer.

"they go super low, but you have to put them in a window or a special hole in the wall" That's an IB or Infinite Baffle alignment.

Danley principle?

I think the video misses then main benefit of the mforce. With its 0.25 resistance it barely creates any power compression at all as the current only drives the cone and lacks the standard 1000s of watts heat loss. In addition to that the driver will not shift parameters as a standard woofers as there is no Long term heat aswell.

@@bassdabob Thanks

Yes, but that'd introduce unnecessary complexity and failure modes. In typical applications, it's vital that it's absolutely bulletproof. They have structural heat sinking, plus ample coil area for thermal dissipation.

there are rotary subs as well

No he is thinking inside the sub box.

The quality of live sound can be extraordinary today ... thank goodness.

It's all about level and extension. Our hearing mechanism isn't too adept at discerning distortions and non-linearities in the bottom octaves. That said, it's performance characteristics are stellar. Linear BL curve, essentially zero compression due to extraordinarily huge motor structure.

I believe Dave employs them in the EDM tent at Coachella.

That's a band from Sweden :)

​@@mrsonor1090 Yep, knew it! I saw the sign ...

@@FOH3663 Well, It's a Beautiful Life...

@@mrsonor1090 It's all that she wants ...

@@FOH3663 And I'm also from Sweden, so... Happy Nation. But Don't Turn Around because it's a Cruel Summer (this has gone to far... make it stop)

In loudspeakers, speed isn't impacted by weight. Weight does impact sensitivity, but not speed. Speed is a function of how much current can be instantaneously pulsed into a voice coil, and that current is limited by inductance.

The motor being on the "front" has zero negative impact on performance. The 56 foot wavelengths of a 20hz tone aren't impacted by the motor out front. Even way up top of the sub's range at 80hz the wavelengths are 14 feet ... so the mechanism is still acoustically small.

@@FOH3663 I should have considered the actual wavelength, I stand corrected, thx.

@@flamencoprof It's so helpful to automatically associate a wavelength with a given frequency! That size orients you to essentially all acoustic interactions, everything's about wavelength size. Plus, historically flipping the driver over with the motor outward is advantageous for cooling. I'm sure there were more, but early on in the 80's TAD, EV, and I believe EAW had motor out subs/platforms, as they explored distortion lowering and motor cooling.

@@FOH3663 I am well-educated re frequency vs wavelength. However, despite a lifelong interest in guitar amps, I have never investigated the world of high-power low-f speakers. The cooling effect is obvious once pointed out. Even at over 70, I appreciate learning new things. Thx.

I think Dave was talking about driving the speaker without acoustic loading. I'm not really into designing and simulating boxes, but maybe if the driver can safely move at a certain frequency under high power without burning itself, then when acoustic load is added by a box, the output will be higher than a normal speaker.

@@kristofnagy1574 Oh ok.. thanks. :)

An 18", 12hz capable transmission line would lack level, and freedom from BL non-linearities and compression, ... vis-à-vis this platform.

Using a subwoofer to communicate with elephants has been done before, several decades ago, with a 30" subwoofer mounted on top of a Jeep. ElectroVoice had a 30 inch woofer in 1958 and there have been a few others since then.

Powersoft M-FORCE 301P02

@@kristofnagy1574 Great. Thanks.

@@NNokia-jz6jb No problem!

That really depends on your music goals or sonic goals because I have friends who can play down to 12Hz and shake all the windows and have a fun doing it. In fact, one time I was playing a 17 Hz tone in my car and a lady gave me the middle finger; that was awesome.

You can’t hear it perhaps but you can feel it in your chest

Sorry nobody can hear LFOs, that’s the point.

​​​@@Bassotronics, Yeah, that's why we put audio systems in our cars, to listen to "tones". This may fall on deaf ears, hopefully not literally: try listening to music instead, that's a novel concept nowadays. And before you write me off as some old fuddy-duddy boomer, that's simultaneously both true and false. I was installing car stereos for my friends beginning in 1974, and by 1983 I had a triamped system in my car with 10" Dynaudio subs in a tuned cabinet I built, Fosgate and Audiomobile electronics, a/d/s speakers and a Nakamichi tape deck. My work was sufficiently well respected locally that I even installed Nakamichi systems in a half-dozen Saabs for the president of Saab-Scania US and his executives. The emphasis back then was on sound systems that were clean and *musical*, but I went to the Vegas CES show in 1988 or 1989, and of 60 or 70 cars out in the parking lot that were being used to demonstrate car audio equipment and systems, I only heard 3 that sounded good (Fosgate was one of them, I don't remember the other companies). People were going for loud volumes and heavy bass, and a completely imbalanced audio spectrum. Selling and installing an expensive system & installation to people who just wanted to be loud was easy enough, but there was no satisfaction in it. I got out of the business in 1990 ( became a telecom tech for a while, then spent 20 years as an audio-repair bench technician before retiring). Unfortunately, the years I spent climbing into car trunks and contorting myself to get underneath dashboards did some bad things to my back and neck ( I am 6'2" and used to be pretty flexible) and now I'm living with arthritis and pain. My hearing still works at least, although my top end response cuts out at about 13k; but there's not much worth listening to above that, just as there isn't much worth listening to below 40 Hertz unless you listen to synthesizers or recordings of church organs. The fundamental note of a bass guitar E string is 80 Hz with some output an octave lower at 40 Hz,and of course a bass drum goes a bit lower than that, but putting dual 15" or larger woofers in a car makes about as much sense as pouring a cup of sugar on your bowl of breakfast cereal.

@pauleubanks, the wavelengths of low frequencies are so long that back in the days when bass players on big stages would use folded-horn speaker cabinets they could hardly hear themselves but the audience, and perhaps the singer at the very edge of the stage, got pummeled by the bass. It's impossible to reproduce anything audible that low in a car anyway because the cockpit size of the vehicle is so small. Sure, you can feel it , but then you also have to go through every part of the car and install sound-damping material and tighten everything down so that it doesn't rattle.

the old dude is right its just off and on, no smooth transitions between pulses. thats a square wave a sine wave has smooth transitions between polarity flips. the battery on a drill situation would not provide any transition besides an open circuit between polarity flips im not an expert by any means but i think that old guy might know more about this stuff than this "audio university" fellow.

@@Sethfranzpopsicle I don't know jack and the fact that I caught that shid and don't see it anywhere else in the comments is mind blowing.

ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-JWYA-XNIHWA.html

"... they tell me it's the most powerful subwoofer, very powerful, ... so, so powerful that it's more powerful than anything before it, ... a beautiful, powerful subwoofer. Very powerful ... very powerful. The most powerful"