Most home-audio enthusiasts have never heard of Bag End InfraSub, even though its approach to deep bass is fundamentally different from the subwoofer designs found in most systems.

In this video, we visually break down how Bag End InfraSub produces flat response down to 8 Hz, what the dual integrator actually does, and why this technology matters for high-performance music and home-theater systems. For many examples of where Bag End is used: https://www.facebook.com/AcurusAV

Instead of using cabinet resonance to create the impression of deep bass, InfraSub combines a sealed loudspeaker system with dual-integrator compensation. The system corrects the natural low-frequency roll-off below resonance while reducing the influence of the resonance itself.

The result is not simply more bass. The goal is uniform low-frequency extension, accurate timing, controlled response, and bass that integrates naturally with the rest of the system.

In this explanation, you’ll see:

• How a conventional sealed subwoofer behaves around resonance
• Why response naturally falls below the resonance frequency
• How the Infra dual integrator compensates for that roll-off
• How the operating range extends from 8 Hz to the loudspeaker’s resonance point
• Why overload protection is built into the dual-integrator processor
• How different InfraSub cabinet and driver configurations use the same underlying principle
• An example signal chain using the Acurus ACT 4, Bag End Infra-MXB, Acurus M8X, and passive Bag End InfraSub loudspeakers
• Why deep, accurate bass can matter for both music and home cinema

This is a different way of thinking about subwoofers. It is not about exaggerated impact or one-note bass. It is about reproducing the lowest frequencies in their proper relationship to the rest of the soundtrack or recording.

If you care about accurate bass reproduction, high-end home theater, two-channel audio, or the engineering behind truly extended low-frequency systems, Bag End InfraSub is a technology worth knowing about.

Have you ever heard an InfraSub system? Tell us about the system, room, or demonstration in the comments. If this is your first introduction to the technology, let us know what surprised you most.

Learn more about the technology:
https://bagend.com/what-is-infra/

Explore Bag End studio and home-theater systems:
https://bagend.com/products/series/studio-series/

Playback note: Frequencies this low may be felt as much as heard, and many headphones, speakers, and playback systems cannot reproduce them accurately.

#BagEnd #InfraSub #HomeTheater

🌐 Learn more or reach out to us at...
http://www.acurusav.com/
http://www.aragonav.com/
Or,
📧 For Sales Inquiries email sales@acurusav.com

Connect with us on all of our social networks:

On Instagram @ https://www.instagram.com/acurusaragonav
On Facebook @ https://www.facebook.com/AcurusAV/
The ACURUS and ARAGON FANATICS Group on Facebook @ https://www.facebook.com/groups/acurusaragon/
Indy Audio Labs website @ http://www.indyaudiolabs.com/

#HomeTheater #Movies #Music

basically dynamic bass boost for the lower end

Years ago in my pro sound days we were throwing the idea around of putting a bunch of these in the club I was working for . They were not for normal play back . I had a 5 way stereo Martin rig system for normal playback and bands . It was specifically for dance night and used as an effect that could probably shake your very soul . Unfortunately it never happened and the club went broke . I continued on touring with various bands on the road for another couple decades . Interestingly in my retirement I built a pro audio Atmos theater in my barn . For the sub it has an array of 8 JBL 2226's in front loaded  sealed cabinets that couple together and are flat to 20 Hz . That's old school and good enough for me ! Cheers !

I mean, that is basically just EQ-ing until the response becomes flat...l

the only difference being that because the roll-off of the system is extremely predictable, the corrections applied can more accurately compensate for it (assuming the amplifier hardware is powerful enough)

I think this video may have been a bit heavy on details that obscure the main points.  The essence of the system is that it is a sealed cabinet; the cone is not subjected to weird loading and unloading as with ports, and behaves predictably at -12dB per octave below resonance.  This is fed by the dual integrator at +12dB per octave, also with consistent phase rather than the roller coaster you get with extreme EQ.  The result is no distortion, no phase mush or bounce or tubbiness that you get with ports and EQ, and flat response.  You can set these subs at a very low level, almost quiet, and stand at the back of the room and feel the kick drum in your chest.  The improved transient response and low distortion resulting from not smearing phase all over the place produce remarkable results.  When they’re loud, it’s the most remarkably pure bass you’ve never heard.  There’s no other way to do it.

- not affiliated, just a VERY satisfied user for many years.

Loudest bass I ever heard was a P-3 Orion feathering its propellors at low altitude across a body of water.

Short answer: linkwitz transform equalizer.

Suppresses the physical poles and add poles where you want them.

Drawback? Much more power needed and much more THD.

Ampeg used this sort of engineering back in the late 60's on their 8x10 SVT bass cabinets, which used three internal baffles that essentially provided four sealed 2x10 enclosures inside of a single 8x10 cabinet. The matching Ampeg SVT tube/valve amp head was specifically tuned to those multiple sealed 2x10s, which have a relatively high resonant peak frequency above the range of the fundamental notes of the bass guitar, thus providing deep and powerful bass amplification, but with an extended and even frequency response, and without the massive resonant peak frequency "honk" of most other bass cabs of the era...

Dang...I didn't even know Bag End was still around. I remember seeing the ads in Car Audio and Car Stereo Review magazines back in the 90's.

Haven't heard Bag End mentioned in a long time.  Blast from the past!

Cranked the bass knob😂

While Siegfried Linkwitz may have died in 2018 lets not forget his idea of the Linkwitz Transform was essentially this!

We were doing this for auto subs going back to the 80's due to their very small enclosure design. It worked very well because the restricted listening space cause the ear to hear bass as a change in pressure not via long wavelengths.

I got to hear a surround system that was professionally installed using (2) 15 inch Velodyne servo subwoofers one time that was just epic, no other way to put it. I played a war game on it with a friend of mine and when the first grenade that was tossed at us during the game went off both of us jumped. That kind of impact and movement that would crack many normal home drywall set ups was just awe inspiring.

Best explanation!  I've been using Bag End for decades.  Beyond the stats, they sound incredibly pleasing creating the belief the cabinet is physically much larger.

Great work!

7:15 I was searching youtube for this exact time spread of frequencies with regard to thunder - it's a clap of all frequencies that spreads out over time. The algorithm gives me this today!

I saw plans for a similar system with built-in integrating amplifier as a DIY project in a magazine in the early 2000's

Great video.
I have used tunned port speakers for most of my life.
Heard nice transmission line speakers and recently experimented with open baffle. But I was never happy with the bass reproduction.

I just built a pair of sealed bass speakers that handle everything below 200Hz.
I use a 24dB/oct active crossover with adjustable sub boost.

These give a totally different bass experience...
No boom, fluff, or port noise!
The positioning is not critical... They pressurize the entire room.
The speaker excursion is amazingly short even at high volume.
Most surprising is that bass now contains directional information... So deep bass now has a soundstage too!

Turns out that adding more resonant components such as capacitors, inductors, ports and resonators really does compound the unavoidable problem of room resonance.

As a hired FOH engineer in the 1990s we were headed to support a legendary band from another continent. The sound company owner had just purchased a new P.A. featuring the BagEnd ELF and said he had not tried it. 😲 I studied acoustics & read about ELF but had never touched it. It setup rapidly, I re-soldered some XLR connectors to respect phase (both Crest & Crown amps were in use), and as the flux fumes were still rising the band took the stage. The system worked and the sound was noticeably special! Patrons kept talking about the "velvety" & "silky" rich sound.  The classic Brit band called me their "Vicker of Sound". I'm sold. Not merely the frequency depth but probably the phase alignment makes this technique yield such a wonderful sound experience.