Maximizing cabinet efficiency

It's not trial and error, but it's engineering knowledge. The point is that it's expensive to know the fatigue curve for the material and for sure companies may evaluate them, DIY is a different history and it's more trial and error.
DIY is what i mean when i said
maxolini said:
As looks like by trial and error people find drivers that can survive a high compression enclosure
the word People do not refer to :Audio Companies, Audio Manufacturers, Audio Enterprises ,R&D Dept or the NASA Acoustics Labs. 😎

People means " We The People"
Humans that do not have the means in either money or
equipment such as
Anechoic Chambers to test
Rode and Schwartz scopes
Earthworks M30 mics

and mainframe supercomputer to do Finite Element Analysis
and AI Engine to sim and test thousands of virtual models

Cheers 🍻
 
In 2016 I wrote an e-mail do Mr. Don Keele Jr. about the EV T18 project and other stuffs and he replied to me:

"I’m definitely in favor of multi-driver vented boxes over horn-loaded system. Attached is a paper I wrote back in the dark-ages of 1976 when I was at EV. It compares several systems one-of which is the Sentry IV B cabinet"
After reading the EV TL papers, drawing sketches and cost projections while bouncing along in trucks on tour ~1977-8, decided to build horn bass and low mid enclosures- half the drivers and amps was more appropriate for my budget, and I'd been building horns for years during the "dark ages" already.

By the mid-1980s had converted to bass reflex for low frequency output density.

Art
 
@BP1Fanatic

Group delay has entered the chat😝 and the second resonance sounds funny(in the 6th order stuff??? )

All I listen to is Hip Hop. Delayed bass is probably in 95% of Hip Hop music. The Roland TR-808 drum machine has a decay knob that allows you to "drag the bass." When you hear or see people say 808 bass, that's DELAYED bass.

The 808 is noted for its powerful bass drum sound, built from an oscillator, and voltage-controlled. The bass drum control allows users to lengthen the sound, creating uniquely low frequencies that flatten slightly over time, possibly not by design. The New Yorker described the bass drum as the 808's defining feature.

The key to the 808’s popularity is the kick, whose decay can be extended out to ridiculously long lengths. This results in the famous boom, a sub-bass explosion that can felt as much as heard. This boom has been exploited by producers for decades, underpinning standard kicks for extra oomph and even being sampled and used as a bassline.

Screenshot_20240909_231341_Samsung Internet.jpg
 
After reading the EV TL papers, drawing sketches and cost projections while bouncing along in trucks on tour ~1977-8, decided to build horn bass and low mid enclosures- half the drivers and amps was more appropriate for my budget, and I'd been building horns for years during the "dark ages" already.

By the mid-1980s had converted to bass reflex for low frequency output density.

Art

I remember building my 1st BP4 enclosure in 1990. It was a pair of Pyramid Super Pro 1295's for a 1981 Honda Civic 4 Door Sedan. I couldn't believe the smooth distortion free bass that came out of that enclosure...that was improper tuned (the math said 80hz, but I tuned it to 45hz cuz 80hz didn't seem logical in my brain) and the ports were too small (3" diameter) so I couldn't turn it up without port noise. Thank 9od for Linearteam and David McBean for making the world a better place!

I've been addicted to that BP sound ever since.
 
Why not post a non-exaggerated audiophile BP enclosure for a fair comparison to the BR enclosure?
Because I was specifically making the point that some additional limitations were probably necessary for the general premise of the thread. I was demonstrating extremes, not saying that all bandpasses were bad or that those two were the only possible things. As I stated previously, it's all on a continuum and there are too many options to demonstrate them all.

One of the better sound quality cars I heard in my IASCA judging days was a bandpass.
 
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All I listen to is Hip Hop. Delayed bass is probably in 95% of Hip Hop music. The Roland TR-808 drum machine has a decay knob that allows you to "drag the bass." When you hear or see people say 808 bass, that's DELAYED bass.

The 808 is noted for its powerful bass drum sound, built from an oscillator, and voltage-controlled. The bass drum control allows users to lengthen the sound, creating uniquely low frequencies that flatten slightly over time, possibly not by design. The New Yorker described the bass drum as the 808's defining feature.

The key to the 808’s popularity is the kick, whose decay can be extended out to ridiculously long lengths. This results in the famous boom, a sub-bass explosion that can felt as much as heard. This boom has been exploited by producers for decades, underpinning standard kicks for extra oomph and even being sampled and used as a bassline.

View attachment 1354538
Is that the same thing? Or are you suggesting that two ‘out of phase’ pressure/velocity Sources being added to any existing music is somehow adding to the experience or enhancing it further ? The sloppy speaker duct/resonator is a good thing ?
 
All I listen to is Hip Hop. Delayed bass is probably in 95% of Hip Hop music. ... When you hear or see people say 808 bass, that's DELAYED bass.
... The bass drum control allows users to lengthen the sound, creating uniquely low frequencies that flatten slightly over time ...
whose decay can be extended out to ridiculously long lengths... even being sampled and used as a bassline.
None of this has anything to do with "delay", which is a signal arriving at a different time. Perhaps you're thinking of a long decay on a bass kick/note, when referring to hip hop music.

An acoustic kick drum is a helmholtz resonator (aka ported box) that is excited by an impact to a membrane with an initial transient sound, the resonator then rings out to give the "boom".
Synthesized bass drum sounds emulate this by exciting a resonant circuit or oscillator with a trigger signal, and having decaying envelope on both pitch and amplitude.

The decay knob on the 808 controls how quickly the oscillations are brought to zero amplitude. Letting the 808 kick ring out with the decay wide open gives you a nice droning sinewave, which is what is sampled for basslines.

Parallels with a ported box? I could think of a few... but you want your source to be providing the resonance and ringing out, not your subs creating it.
 
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That means (making room acoustics aside) there is "tight" subs and "loose" subs

Resonance and ringing must be not created by the sub.
In order for the reproducing system to be "transparent" not adding or subtracting from the source signal.

The more coherent and transparent the signal link is , preamp ----> processor ----> power amp ---> speakers

The more faithful and representative the sound stage image is from the source recording.

Or from what audio picture the FOH engineer mind to give to the audience using his mix board ,processing and audio skills as canvas and brushes to portrait a colorful and impacting representation of the performing artists and musicians to our ears.
 
I bet it rings like crazy at 86 and 140 hz ? Shoulda built a bass reflex version (just kidding!!)😝

i have the same thing and they sound really good down low
 

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