Because how good something sounds is largely based on your own ears

Huh, neat, yeah I've seen a video of a jet without winglets going through an enormous smoke screen and seeing toroidal vortices the size of the plane itself, without winglets, is crazy, and yeah, I suppose it is an equivalence. One thing would be the time it takes the wing to travel its length would be the tuning frequency, so I'd expect thicker wings to require longer winglets.

1:41 This is done in aviation as well with the addition of what is called winglets. Adding wing-like structures to the wing tips does the same thing as the baffle by preventing the low pressure air from meeting the high pressure air in the best possible manner. Winglets are prevalent on most airliners flying these days because they reduce the drag induced with the lifting motion of the wing. Thank you for the explanation this. I am really amazed. Very well done! Cheers, be safe, and stay healthy!

Yeah, I haven't seen a good explanation of the difference between an acoustic suspension and infinite baffle other than smaller than vas and larger than vas respectively, but driver Qts is an important factor, for determining enclosure Qtc, which is why I think it should be a factor in enclosure choice.

@@Dakoustics Agreed.

4 15's for SQ is crazy

Not true. Ib gives you faster sharp tones, the reason it does it because it doesn't need any load other than the mechanical load of the driver. You must be using a driver with the wrong parameters.

@@dooflydetailguuy4349 i dont think he was referring to IB in either case here. OB vs box (AS, ported)

I've just had a good look at the equation for Qts, it seems the reason the Qts increases for smaller boxes is due to the compliance decreasing. If the mechanical resistance isn't altered much by the air, then it does seem the damping goes down with higher Qtc. I believed damping increased due to the restriction of the driver movement below resonance, but this is quite interesting. I originally theorised the air providing damping to the driver, as air (N2 and O2) isn't very springy compared with, say, carbon dioxide and sulfur hexaflouride, and this lack of springyness also contributed to damping. I should mention that I'm mostly self tought, and the Q's are the most recent area of audio I've looked into, but this has inspired a sort of epiphany.

@@Dakoustics A dynamic speaker near its fundamental resonance frequency can be approximated by a weight on a spring analogy. The greater the weight or the softer/more compliant the spring, the lower the resonance frequency. Conversely, the lesser the weight or the stiffer the spring, the higher the Fs. The formula is 1 over 2Pi times square root of Moving mass times Compliance with mass expressed in kilograms and compliance in metres per Newton of force. 10 grams of moving mass with 1mm/N of compliance equates to a fundamental resonance frequency of about 50Hz for example. Note that any combination will yield the same result as long as their product is the same. Air is unfortunately not a very good match for the cone, not a good medium to conduct/transmit the vibrations produced, as it presents very low resistance to its motion. Less than 1% of speaker input power turns into sound actually because of that, the balance turns into hot, not moving, air to put it simply. Air is too thin, too light, hence the invention of the horn enclosure, but that's a topic for another discussion. Mechanical Q or Qms tells you how long it takes for the cone to stop once pushed out of equilibrium. In short the longer it takes the higher the Q (heavyweight cone + soft spring) or low damping. The faster it comes to a halt, the lower the Q (lightweight cone + stiff spring) or high damping. All bass drivers fall somewhere in-between these two extremes. (Please note that listed moving mass values, Mmd and Mms, differ by inclusion of the cone loading for the latter, which is the weight of the air that "sticks" to the cone) Now make the weight out of iron and suspend it in strong magnetic field. If you try to move it abruptly now, that piece of iron will interact with the field and work along the suspension trying to keep the weight still, it will dampen the weight motion. And that's your Qes - the electrical damping, the stronger the magnet, the more turns of the coil wire inside the magnetic field, the lower the Qes, the higher the damping and finally the quicker the dying out of the post impulse cone oscillation. Here's where amplifiers play their part - low output resistance/high damping factor or lots of easily drawn current will considerably impact the cone motion. Considerable output impedance value adds to the speaker Revc value in short. That's also the reason why vacuum tube amplifiers with their impedance matching transformers are not be the best choice for low frequency reproduction in general, as the tubes are excellent voltage, but mediocre current amplifiers, but I'm digressing. Both Qs, both damping systems, then average out and give you the total Qts of the speaker, Qts = Qms x Qes over Qts + Qms). I admit, I have intentionally omitted the mechanical resistance of the suspension, Rms contribution to simplify the picture. It has a direct impact on the Qms value and can be approximated by turning the spring into a full blown car suspension shock absorber. It dissipates the coil vibrational energy, turning it into heat basically, and the higher the losses the lower the Qms, it does not directly impact the Qes value. Neoprene surrounds have high Rms values, pleated textile ones the opposite. Worth mentioning at this stage, that voice coil former material choice may increase total losses considerably due to interaction with magnetic field. So called cabinet losses itself also play its part, but again this a rather complicated subject and requires a lengthy discussion. Three simple equations describe the Qms, Qes and Vas parameters values, with the dynamic speaker equivalent circuit being the foundation for estimating the influence of the enclosure. Ambient air pressure and humidity for example, will also influence the parameters just as dynamic changes in response due to voice coil increase in temperature at higher loading levels. But the above is a gist of it I would think and the more you learn and explore, the less you know actually, as you dig deeper you only uncover layers upon layers of additional considerations. That's what makes it fun. If I may recommend a course of action it is to start at the beginning, familiarize yourself with the equations and books on speakers, beginning with those often published nearly a 100 years ago. This will give you the insight and idea on how our understanding evolved until this day. I've been playing with speakers for 25 years myself and If you asked me, whether I'm a knowledgeable I'd say no - I barely scratched the surface. Oh and btw, the simplest sealed enclosures, infinite baffle in particular, still sound the best to my by now aging ears. Gradual, albeit early roll-off is compensated by real life in room placement to such a degree, that with the right total cones displacement volume available and moderate levels it just sounds right all the way down. Anyways, love your channel and keep up the good work, only a fool thinks he knows it all !

@@paulb4661 Hi Paul... thanks for taking some of my confusion away. Great add on. I'd love to ask some more questions but don't know how to contact you other than via this comment box so if you wouldn't mind dropping me an email to shabixs@gmial.com to which I could reply it'd be much appreciated. Cheers mate. @Dakoustics great vid btw.

@@paulb4661 Good stuff ... Agreed, especially the middle of your comment, electrical damping, especially the amplifier aspect ... The short answer to the ubiquitous question about "fast bass" ... the key to woofer speed is instantaneous current availability. Fast bass in a general sense is a multitude of elements ... primarily a function of LF decay characteristics of the room.

@@FOH3663 Spot on Mate - loudspeakers' interaction with its surroundings is massively understated, placement first of all is of paramount importance and then at least a modest application of damping mats, at least where the first reflection takes place. Then of course concrete vs suspended timber floor, brick wall vs drywall and so on will massively influence low frequency characteristics. Dont you just love modern spaces full of hard surfaces with not a book shelf in sight ? 🤣 That zingy and fluttering echo - perfect .... not.

1. The efficiency is measured at resonance, so as the stiffness increases the resonance, it leads to it having a higher spl measurement at the new higher resonance, thus "higher efficiency". Maybe higher sensitivity would be more correct, but much of a muchness. 2. Variation in group delay is likely due to phase response wierdness around the resonance also. Cheers for the comment, hopefully this'll clear things up.

no problem heh

Group delay is basically an effect where certain frequencies take more or less time to get from the output of an amplifier to our ears, via the speakers. Example- You have speakers against the opposite wall, but the sub is next to the couch. The speakers will have a delay relative to the subwoofer. Example 2, a ported speaker- tuned to 40Hz, plays a 60Hz tone. Sound goes straight from the amp, to the speaker, to your ears, not much delay. But, if you play 40Hz, it goes amp, speaker, then the port absorbs a certain amount of sound before it starts to resonate properly, and this results in the sound taking longer to get to your ears.

Yeah, got that backwards, was taught backwards.

I'm so confused now

You are spot on, he got it all backwards: higher Q means less damping and not more. A Q of less than 0.7 in it's mounting is considered over-damped and suffers in loss of bass. But if you compensate the loss with a DSP, then you get a very controlled system.

How did it go?

I tried it sealed and then added a port. It worked pretty well sealed and had a nice wide range but I prefer the sound of a ported enclosure.

@@gregblau8082 Roger that; to what did you tune?

31

Yes, it'd be infinite baffle. It'd have a low-ish Qtc, so balanced more towards peaks than tones, but main thing is be careful not to over-excursion it. At 17L, too, could be enough for it to be ported if you wanted.

Isobaric (1/2 vas)

Loudspeaker Design Cookbook is good from what I've heard, I should pick up a copy.

Crutchfield..

Holy crap, 16 18s! I can honestly say I don't know of a car audio build with more than that, except the 40 15" solobarik truck, but that's it. 3300 cubic feet is hard to fathom. Might be time for some structural reinforcement at that point. I've seen a bit on the stereo integrity 24" subs, craziness. I'll keep my eyes open for the next upload.

@@DakousticsI'm going to do a quick video today just showing the updates to the theater's configuration. I'm excited for the next part of my build. Almost as excited as I am to see where your build goes! The world needs more clean, ultra low bass!

Budget Audiophile your goal shouldn’t be to put as much power to the sub as possible. SPL is a product of xmax and cone area. Thats it. So you technically get more out of IB than sealed and you can play way lower

@@JayeBass I see what you're getting at but at the same time, 200w/sub is going to have a lot more headroom than 50w/sub. Digging deeper at a given level requires more wattage for a given driver. It's just electromotive forces in action.

IB is the way to go to get really low frequencies..but.. you can actually damage your house by going too crazy with it. Sound can be incredibly powerful. Do LOTS of research so you really understand it before you start your build. Good luck with your project!

Only real option is a ton of cone area, but to keep the lows not too much cone area or they'll be choked. Like a box more common in the 90s, with 8 12" subs in a 10 cube sealed box.

@@Dakoustics I just saw a video where two infinite baffle 18's on 400W total did a hair trick at 18hz.

WinISD Pro Alpha should be free off the website

I’m no scientist, but I would imagine it wouldn’t perform at all…if a vacuum was present inside the enclosure then it would be pulling the driver inward and would not be able to move to produce sound.

@@brandonhooker4498 Yes, of course the difference in pressure between the inside and outside of the enclosure would create a force pushing against the speaker driver. But this force could be overcome - either by increasing the power of the driver, or mounting an internal spring pushing the driver outwards.

Sealed being described as more efficient than infinite baffle is a reference to their use of the back pressure. IB ignores the back pressure, whereas sealed uses the back pressure to boost output at a higher frequency, so its more conceptual than practical. WinISD is what I muck around with every so often, I do build boxes, but simulations are much easier to muck around with than building a box and having every driver with every possible specification. It's also much easier to describe performance with a clean simulation than buying a couple subs and building boxes for them.

Dakoustics i understand that. It just doesnt always show what really is going on especially with IB. For example i’ve got 2 Tumult 15’s. WinISD would show their response startin to taper off around fs. But in reality they peak around 15hz with the amplifier they’re connected to and could be much lower with an amp that doesnt have a subsonic filter @10hz

@@JayeBass yeah, thats a good point, if you're interested in my "4th order v 6th order" video I mention how cabin gain massively improves the low-end performance of 4th order bandpasses, so although winISD would have you believe band passes are... welll... band passes, they in fact act more like low passes due to the +12dB/octave gain keeping up with the -12dB/octave roll off of the sealed portion of the 4th order. It'd be good if WinISD could process cabin gain, I've seen people comment it can with filters, but I haven't checked it out yet

yeah, talking about windows audio drivers, I know it gets confusing, one guy got my submarine video confused with subway, the sandwich lmao

😆

Yeah, got Q's backwards lmao, but yeah main point still comes across, small sealed tunes high/is peaky, big IB tunes low and smooth.

@@Dakoustics That totally depends on driver Q, a low Q driver will have no bass output in an infinate baffle where a high Q driver will sound very good. Acoustic suspension use small boxes to lift the Q at the expense of efficiency whereas a more conventional sealed cabinet will be larger and not use such a small box to bring the Q up to required spec with the extreme end being infinite baffle with a very high driver Q that does not require being raised by the cabinet. A low Q driver in a small box will not be peaky, just not efficient compared to a big box higher Q driver with the same F3. Basically the size of the box controls the efficiency/extension equation and you can load that box any way you like, with a ported or passive radiator system yielding lower distortion/ cone movement than any sealed driver.