ASR measures the Neumann KH150

[Dissident]

@kanyewest

With a cardioid you throw away 80% of the sound energy and make your subwoofer way less efficient.

not necessarily … it all depends on the size of the enclosure and frequency …

with large enough enclosure and high enough frequency cardioid can be MORE efficient than a sealed box …

remember sealed box uses only front wave but cardioid uses both front and rear wave, it’s just that rear wave is out of phase …

but it’s only out of phase because box is small and frequency low …

with larger box and higher frequency it can be in phase …

which is why my speaker design was large with additional delay crated through internal folds of transmission line and high passed at around 100 hz …

@kanyewest

Cardioid subwoofers basically serve one purpose: to reduce the sound energy going to the stage so that the performers don’t go deaf and can hear themselves play. They are useful in live sound but not very useful otherwise.

if you don’t use cardioid your speaker will have a baffle diffraction step where it transitions from being directional to omnidirectional …

with a cardioid midbass you can eliminate this step completely by keeping the speaker directional at all frequencies …

of course it now won’t actually be able to go much lower than 100 hz …

but that’s what subs are for !

i didn’t say my design used cardioid subs but cardioid bass ! ( 100 hz - 250 hz or so ).

i just needed the main speakers to get down low enough to where the sound can no longer be localized then hand off to subs distributed throughout the room including on the ceiling !

@kanyewest

The best way to minimize boundary interference with subwoofers is to place them on walls and corners. Better yet, build a single bass array or a double bass array. You have all the benefits of arrays and cardioids.

if you can do custom stuff like flush mounting speakers into the wall as they do in recording studios that can solve a lot of problems.

i wanted to challenge myself to design something that can be placed in any room.

the beauty of a cardioid is that it will work the same whether there is wall behind it or not.

a sealed box may be efficient in an open space but when you place a wall behind it you may get a null which might take a lot of power to EQ.

what’s worse is you may also get very weird effects where the sound appears to come from a different direction than where the speaker is because you may get on-axis null but a peak at some other angle and when you EQ that null you boost that peak then suddenly the sound is coming from completely different direction bounced off some wall or ceiling.

ok i exaggerated that a bit. it probably won’t be that bad. i did experience exactly this though when my speaker and sub were out of phase and i boosted up the crossover frequency and suddenly the bass was coming from the ceiling … because horizontally there was on-axis null but vertically there was a peak, which once i boosted the frequency bounced off the ceiling …

a cardioid can help with stuff like this, but obviously it will have to be big and powerful and even then i wouldn’t try to take it lower than about maybe 60 hz … at that point you would need normal subs and some other way to control the room, such as spreading the subs around randomly.

[Dissident]

read up on the way shotgun microphones work.

shotgun microphone is an end-game cardioid microphone.

i simply reverse engineered it to crate a shotgun subwoofer and then i folded it into flower shape to save space and optimize radiation pattern.

i am so brilliant sometimes i scare myself.

the obvious problem is that nobody knows how to tune such a system so getting it right might require experimentation.

we can model similar enclosure types like transmission lines, dipoles etc but those would only get you in the ballpark. you wouldn’t know what the result would be until you built it.

yet anther reason why i am not actually going to do it.

[Dissident]

essentially the difference between a shotgun and a cardioid is that a shotgun uses an array of multiple slits or vents whereas a cardioid just uses a single vent ( or a second driver that is delayed and inverted ).

this makes cardioid simpler but it doesn’t perform quite like a shotgun because the delay is sensitive to frequency. whereas multiple vents each with a different delay will randomize and cancel out more evenly.

a shotgun is basically a transmission line that has resistive vents all along its length.

we can build a speaker using the same principle as mics and speakers are the same thing just in reverse.

Dave Rat has a good tutorial on cardioid subs:

Live Sound Subwoofer Configurations Part 3 - Cardioid Arrays

ultimately real cardioids have limitations.

i called my system a cardioid to make i easy for you to understand but it’s actually a shotgun.

so it is literally beyond anything in existence in terms of pattern control.

my Genius truly knows no limits or boundaries.

[kanyewest]

The passive cardioid bass concept has been employed before in speakers like the Kii Three, Dutch&Dutch 8C, ME Geithain.

You can look at the measurements of these speakers to see what the problem is with such a design. The cardioid controls directivity, but at the expense of efficiency. For all of these speakers distortion is high even at lower levels, and max output is significantly reduced. If there were no DSP to flatten the frequency response you would see a dip where the cardioid is employed.

You can model this design in software like VituixCAD. You will see that you can get the pattern control you want normalized to the on axis response, but the on axis response is weakened.

A cardioid, supercardioid, hypercardoid, shotgun, whatever will always face this problem. When you use multiple omnidirectional sources of sound to create a directional source of sound, it’s inevitable that destructive interference will leak into the directional sound. The goal is just to have more sound in one direction than the other even if it comes at the expense of efficiency.

[Dissident]

@kanyewest

You can model this design in software like VituixCAD

OK then. my design was for four 15" JBL Pro woofers ( per side ):

https://www.parts-express.com/JBL-2265HPL-338343-003X-15-Neo-Woofer-294-452?quantity=1

using a cabinet 3 feet wide and 3 feet deep and only working down to 80 hz. you can simulate it in your software and report your findings. however i already did the math as it’s trivially simple for a genius like me without any software. my design also included internal baffles for additional delay of the rear wave but you can ignore that and you will still find there is absolutely no deficiency of any kind above 80 hz.

my design was for two 3-way line arrays + distributed subs. so the cardioid section would roughly cover 80 hz - 250 hz or so. or pretty much the same range these woofers would cover in a 3-way PA speaker when crossed to subs.

my cabinet design was such that i would actually begetting GAIN from the rear wave throughout the entire operating frequency range. yes blow 80 hz there would be severe loss of output but i wouldn’t use it there anyway.

@kanyewest

A cardioid, supercardioid, hypercardoid, shotgun, whatever will always face this problem.

yes, which is a complete non-issue when the system is correctly sized.

@kanyewest

When you use multiple omnidirectional sources of sound to create a directional source of sound, it’s inevitable that destructive interference will leak into the directional sound. The goal is just to have more sound in one direction than the other even if it comes at the expense of efficiency.

absolutely not true !

destructive interference only has to occur at certain frequencies and you may design the system to fit your entire operating range between those frequencies.

i went a step further and designed a system with multiple random delays by using multiple resistive vents instead of one ( as previously explained ) which allows me to optimize even further.

think back to JBL VTX F35 - it has slot loaded woofers where the slots have band-pass behavior but it’s precisely tuned to the frequency range the woofers operate in.

it’s all in the details. you need to design it so that you put the gain in the frequency range you want to use and put the nulls outside of the operating range. in my case i both put them outside and also randomize them out.

[Dissident]

i really think you under-estimate my IQ

i have already thought about all the problems you mention, researched them and solved them

in fact i knew about most of this stuff 20 years ago

i’m not even claiming to be the smartest person on earth - the guys at JBL whose AES papers i read are smarter than me

the problem, as i explained, is that there is no profit in using sound engineering in a product for an Audiophile market.

Audiophile products simply aren’t judged on performance …

there aren’t even any accepted metrics to judge them !

ASR will obsess over 0.01% THD vs 0.001% THD while even 1% THD is inaudible.

Audiophiles are lost puppies.

[Dissident]

@kanyewest

The cardioid controls directivity, but at the expense of efficiency. For all of these speakers distortion is high even at lower levels, and max output is significantly reduced.

i would bet my life that my cardioid array would slaughter your Neumanns in both efficiency, output and distortion.

[kanyewest]

If a cardioid/shotgun were such a brilliant idea then why aren’t pro audio companies using it in their speaker designs? It’s not like they don’t understand the concept. Some of them already use it in their subwoofers. The technology already exists and has been employed in the products I mentioned.

Well the answer is simple. All the cardioid does is reduce sound energy. Ideally it would reduce sound energy in the direction opposite that where energy is meant to be directed. In reality it reduces sound energy in every direction. A speaker whose sound energy is mostly cancelled out in every direction is not a good speaker.

That is why it is better to use wall mounting, arrays, beam steering, etc. to control directivity. Canceling it out is not a good solution.

[kanyewest]

And you wouldn’t be able to use them as nearfield monitors, so it’s a moot point.

[Dissident]

@kanyewest

If a cardioid/shotgun were such a brilliant idea then why aren’t pro audio companies using it in their speaker designs?

size and weight and flexibility.

you can make a cardioid out of two vented boxes but you can’t make a vented box out of two cardioids.

vented boxes offer best tradeoff overall.

@kanyewest

Well the answer is simple. All the cardioid does is reduce sound energy. Ideally it would reduce sound energy in the direction opposite that where energy is meant to be directed. In reality it reduces sound energy in every direction. A speaker whose sound energy is mostly cancelled out in every direction is not a good speaker.

you don’t understand the effect of frequency and baffle size on output of dipoles and by extension cardioids.

here is a chart from Linkwitz:

this is for a dipole, but cardioid is same idea.

below F equal there is a net loss, as you say.

but you seem to think there is net loss everywhere, but the reality is opposite.

above F equal there is a powerful boost, that is about 2 octaves wide. my speaker exploits this boost. there is no loss at all in my speaker - only gain.

@kanyewest

And you wouldn’t be able to use them as nearfield monitors, so it’s a moot point.

i was not planning to use 8 feet tall speakers capable of 150 decibels as nearfield monitors LOL.

[Dissident]

@Dissident

here is a chart from Linkwitz:

link to the page:

Electro-acoustic models

the discussion is for dipoles but the math would be the same for cardioid more or less …

i literally knew all this stuff 20 years ago …

[Dissident]

@Dissident

the discussion is for dipoles but the math would be the same for cardioid more or less …

a cardioid is simply a dipole that places the null towards the back of a speaker instead of having two nulls to the sides

but the nature of cancelation is the same

and the effects of frequency are the same

[kanyewest]

I estimate your IQ to be in the 130-140 range. It’s higher than that of almost everyone you meet, and basically every audiophile, but it’s not elite tier and not high enough to warrant arrogance. Also, you say you are Jewish. Like most Jews you probably have a bent towards verbal IQ and a visuospatial IQ closer to normal. Understanding acoustics is largely about visualizing the behavior of waves in three dimensional space. If you understand acoustics in this way you can look at a speaker and predict with a high degree of accuracy how it will behave.

When you are in the 200+ IQ club like me you talk about audio merely for fun. The problem when are this brilliant is that there is little point in using speakers in the first place because you can only use speakers to listen to other people’s music or perhaps your best attempts to bring your own music into physical reality. The music you hear in your imagination is better than anything out there, and it already sounds perfect in your mind.

That is my biggest struggle in life. Finding the will to create. I already struggle with the fact that my mind is racing with so many ideas that there is nowhere near enough time to pursue them, and I am always distracted with new and better ideas that it is difficult to care about them long enough to pursue them into anything worthwhile. If I do actually bring my ideas into fruition they will never be as good as what I envisioned, and hardly anybody would be able to appreciate them anyway. That is why I feel satisfied simply keeping them in my head.

[Dissident]

@kanyewest

I estimate your IQ to be in the 130-140 range.

correct.

@kanyewest

Like most Jews you probably have a bent towards verbal IQ and a visuospatial IQ closer to normal.

that may be true of most Jews but i am the opposite. or maybe it’s just because English is my 2nd language.

@kanyewest

Understanding acoustics is largely about visualizing the behavior of waves in three dimensional space. If you understand acoustics in this way you can look at a speaker and predict with a high degree of accuracy how it will behave.

some of it is visualizing, some is math.

@kanyewest

it’s not elite tier and not high enough to warrant arrogance.

is it arrogant to defend your ideas which you have thought extensively about against somebody who has thought much less about them but claims without any proof that your ideas will not work ?

what do you want me to say - that cardioids can’t be made to work ?

cardioids are a very limited type of speaker. my design was to use them strategically for only a single frequency band where i estimated them to be the optimal solution for a number of reasons such that for example the dimensions would match the dimensions of the midrange waveguide and the frequency range would just hand off from where the midrange waveguide became ineffective thus potentially extending directivity control down to subwoofer crossover …

part of the appeal in this case was the novelty. IMO if you’re going to DIY something it should be original. my cardioid as i said would have been a sort of a transmission line that is lossy across the entire length, which to my knowledge is something that has never been done even though that’s exactly how shotgun mics work.

it’s been like a year though so i don’t remember the entire thought process but i considered everything you brought up and much more.

i also calculated output capacity for every frequency using the formulas from JBL paper that account for imperfect summation from line array elements

i was at pretty much absurd SPL capacity at every frequency above 50 hz or so at which 21" subs would start to run out of excursion …

above 50 hz the max output of the system tracked the average energy distribution of music in the frequency domain almost perfectly, but with about 30db headroom over rock concert levels, which was a major part of the design …

below 50 hz it was not economically feasible to do anything though most music is above 50 hz …

bass is way too expensive to produce and no amount of ingenuity can really solve this cost problem …

this is how i came up with the idea of retunable subwoofers like those SVS where you can plug some of the ports so you can either tune them to 35 hz and use as PA Subs or to maybe 16 hz and use as home theater subs or in between …

in other words the subs would only be able to keep up with the mains when tuned as PA subs, but because of the headroom available in the mains they could be returned for lower output but deeper tuning and then you can only use about 1/4 of the power of the mains before the subs run out of juice but that would still be more than enough …

[Dissident]

@kanyewest

When you are in the 200+ IQ club like me you talk about audio merely for fun. The problem when are this brilliant is that there is little point in using speakers in the first place because you can only use speakers to listen to other people’s music or perhaps your best attempts to bring your own music into physical reality. The music you hear in your imagination is better than anything out there, and it already sounds perfect in your mind.

for you the Neumanns may be a good choice. your brain can recreate the missing bass from the information contained in the harmonics.

most people like to feel the bass with their body. for that you want a 15" woofer and a pair of 18" subs per side.

i once had a high end custom car audio system without subs ( car died before i could install the subs ) and it sounded quite psychedelic. if you want that kind of sound that tickles the brain rather than satisfies the body small monitors might be what you need.

i never used my 5" JBL monitors on their own without subs but i imagine they would sound similar, just not as loud.

audio is to some extent a fetish, so you have to just try different types of speakers to find out which type you’re into.

some people are happy with surprisingly low-performance speakers like a 3" fullrange for example. others will put a 24" subwoofer into their honda civic and enjoy one note bass at ear drum shattering levels. neither is wrong - the only real mistake is not trying different things.

[Dissident]

@kanyewest

That is my biggest struggle in life. Finding the will to create. I already struggle with the fact that my mind is racing with so many ideas that there is nowhere near enough time to pursue them, and I am always distracted with new and better ideas that it is difficult to care about them long enough to pursue them into anything worthwhile. If I do actually bring my ideas into fruition they will never be as good as what I envisioned, and hardly anybody would be able to appreciate them anyway. That is why I feel satisfied simply keeping them in my head.

read some Robert Greene ( ok all of it ).

won’t miraculously solve your problems but should help to some extent.