Bag End Infrasub, the latest subwoofer scam?

[waynel]

What such charts like those miss (not purposefully) is that low and sub sonics are infrequently encountered absent other tones, except in test environments. That is, the charts do not account for the effect of low sonics on each other and on other, higher sonics.

I return to resultant pitches. They are not just difference tones (signal A minus signal B) but also sum tones (signal A plus signal B). Play two pitches simultaneously, they will produce other pitches both higher and lower in pitch. For example, 16Hz (C) played simultaneously with 24Hz (G) produces 8Hz C AND 40Hz, somewhere between D# and E. (That out of tune sum-tone is part of the aural funk you hear in resultant stops. - intermodulation or, you prefer, timbre).

Pitches beat against each other in space and it is possible to detect low frequencies by their modulation of higher-pitched readily hearable frequencies long before they are detected in isolation. We hear not just directly but also by implication. Leave out the sub and infra sonics and you may leave out intended IM (timbre) as well as the cues about the recording venue's dimensions.

(BTW, what are wow and flutter if they are not infrasonic modulation of the intended frequencies.)

Tuning a piano (without tuning aids other than one or two tuning forks) employs beat frequencies (0Hz & 1-1.5Hz) the former to set unisons, the latter to set temperament. This is all accomplished well below the thresholds suggested by the charts. Otherwise, piano tuning would have to be classified an hazardous profession.

you keep returning to resultant pitches but I fail to see the relevance in a discussion of subwoofers. Two tones will produce intermodulation i.e. sum and difference tones only we combined in a non-linear system. In the case of hearing a resultant organ tone the dominant non-linearity is in the ear. Sure the air is non-linear if SPL is high enough but this difference tone will be tens of dB down from what the ear is producing and very little energy will be captured by a microphone at the difference tone.

Therefore a sub capable of 16hz is not needed to intermodulate 32 and 48Hz, So long as your speakers/sub can reproduce 32Hz, your ear fill in the percieved tone. However, for a real 32' stop 16hz tone you will need a sub capable of 16hz.

I like your user name btw , big Parsifal fan.

 

[audiofooled]

I found that ULF is usually not heard as a tone proper (unless it is very loud) but rather as background noise modulation. The ULF sort of impresses a level envelope on everything else.

Air movement at VLF near DC can modify the time of arrival to the ears and add to the perception of space (Auditory Envelopment), especially in case of stereo content down low and stereo bass setups:

VLF content:

Phase:

VLF spectrum at MLP:

Zoom in phase, unwrapped:

Zoom in on the spectrum:

It's not so much about audibility of the tones at frequencies this low but energy itself and how it affects the rest of the spectrum, i.e. other waves propagating through the same medium, if you will.

There's probably a good reason for these signals being buried deep enough in order not to put a strain on small systems, but there are certain perceptual qualities to be unfolded in systems that are able to move some air.

 

[fpitas]

The explanation I've read is special effects for movies, like helicopters. Normal music CDs only go to 20Hz.

 

[levimax]

The explanation I've read is special effects for movies, like helicopters. Normal music CDs only go to 20Hz.

CDs can go to 0 Hz but players usually high passed around 5 Hz.

 

[audiofooled]

Well, there's this movie effect I described here:

Does 'envelopment' exist? Can it be measured?

maybe i mention a type speaker ( as it's always a type of a speaker ) since immersion is a fabricated mix of artificial sound vs reality no hint be given here yet , maybe in one my live-ranting-videos later in the day , the idea has been bothering me , it always bothers , sigh the typical...

www.audiosciencereview.com

But there are examples of recorded music with VLF content, such as this:

Does 'envelopment' exist? Can it be measured?

Fairly new here, and maybe I'm being misled by the sub-forum heading, but most of the discussion seems centered on speakers, room acoustics, and psychoacoustics. Do amplifiers and/or DACs play a role in envelopment? Is "soundstage" (a seemingly equally nebulous term) related and/or measurable?

www.audiosciencereview.com

 

[levimax]

Air movement at VLF near DC can modify the time of arrival to the ears and add to the perception of space (Auditory Envelopment), especially in case of stereo content down low and stereo bass setups:

VLF content:

Phase:

VLF spectrum at MLP:

Zoom in phase, unwrapped:

Zoom in on the spectrum:

It's not so much about audibility of the tones at frequencies this low but energy itself and how it affects the rest of the spectrum, i.e. other waves propagating through the same medium, if you will.

There's probably a good reason for these signals being buried deep enough in order not to put a strain on small systems, but there are certain perceptual qualities to be unfolded in systems that are able to move some air.

Links not working. Audibility of LF content is not settled science but there is little if any content below 17 Hz in the vast majority of cases for music although there are a few examples. In any case a 12" woofer is not going to do anything useful with 8 Hz content beyond possible IM distortion.

 

[Titurel]

you keep returning to resultant pitches but I fail to see the relevance in a discussion of subwoofers. Two tones will produce intermodulation i.e. sum and difference tones only we combined in a non-linear system. In the case of hearing a resultant organ tone the dominant non-linearity is in the ear. Sure the air is non-linear if SPL is high enough but this difference tone will be tens of dB down from what the ear is producing and very little energy will be captured by a microphone at the difference tone.

Therefore a sub capable of 16hz is not needed to intermodulate 32 and 48Hz, So long as your speakers/sub can reproduce 32Hz, your ear fill in the percieved tone. However, for a real 32' stop 16hz tone you will need a sub capable of 16hz.

All things being equal, I prefer having a sub (or several) that will plumb the depths directly.

I like your user name btw , big Parsifal fan.

Notice also, our Mr. T. typically resides somewhere in the basement.

I brought up resultants primarily to inform one poster that resultant pitches (below 20 Hz) were fairly routine in music (organ particularly) whether caused by instruments with the requisite compass or as resultants. Also, to point out that direct audibility (including pitch identification) was not required for single digit Hz phenomena to be perceived.

 

[waynel]

All things being equal, I prefer having a sub (or several) that will plumb the depths directly.

I'm with you on this, I prefer subs that can play 16 hz organ fundamentals. See my main system in my signature.

 

[Wolf11Man]

I have got a quite cheap Behringer PA amp, the i-Nuke 3000 DSP. It has a build in DSP that can be programed via USB by a Windows PC. It has different equalizers, all kind of filters etc. One interesting function is the frequency dependedt limiter. It does exactly what bagend does, reducing load on the low frequency with rising power output.
If someone is interested, the software has a demo mode, so you can try it without the Behringer amp connected and play around. Just ask Google for "behringer inuke dsp software download".
This function is very helpfull with amps having much more power than the speaker can take.

PS the i-Nuke 3000 ist no 3000 Watt amp, it only has 2x 550/4 Ohm in reality, which is still quite nice for HT and HIFI. It can drive 2 Ohm loads too

 

[Keith_W]

The main reason I gave away my infrasub was that it violated an important WAF guideline: A speaker is allowed to be inconveniently big or pug ugly, not both.

Fortunately my wife does not apply that criteria to men. Otherwise I would be kicked out of the house.

 

[Chrispy]

You Are Missing A HUGE Part Of Your Bass Experience Without BAG END Infrabass

What happens when an engineer who designs audio electronics finally gets to experience fourteen 18 inch subwoofers working together in one theater? This video, Rick Santiago , Co-Founder of Indy Audio Labs explains what made that experience so powerful, and why true infrasonic bass changes the entire feeling of a sound system.

This is not just about making bass louder. Rick breaks down why deep bass below the range of a typical subwoofer can make music, movies, and live recordings feel more real, more physical, and more emotionally convincing. When a system can reproduce the lowest energy in a recording cleanly, the room stops feeling like a speaker system and starts feeling like the actual space where the sound happened.

Rick also explains how Bag End’s electronics help make that possible. From control and timing, to low frequency extension, to keeping the system clean and natural instead of boomy or exaggerated, the electronics play a huge role in making bass feel believable. After hearing fourteen 18 inch subs in one theater for the first time, Rick shares what stood out, what surprised him, and why infrasonic performance can be the missing piece in a truly immersive audio system.

In this video:

• Why infrasonic bass feels different from normal bass
• What fourteen 18 inch subwoofers can do when properly controlled
• Why deep bass is about realism, not just impact
• How Bag End electronics help create clean and natural low frequency sound
• Why the best bass can be felt without sounding bloated or overwhelming
• How proper subwoofer design changes the entire listening experience

Featuring Rick Santiago of Indy Audio Labs and Bag End. If you care about home theater, live sound, recording accuracy, or simply want to understand why great bass feels so different from ordinary bass, this conversation will help explain it in a way you can actually hear and feel.

Reminds me of a guy called popalock on avsforum who built 16 subs with SI HT-18 drivers. He later did one with 32 IIRC.

 

[FrantzM]

If you truly understood their documentation and the design goals, you might feel differently.

I for one , don't seem to understand the design goals, I haven't read their documentation but if you could provide us with your take on it ... becasue i from what I believe I know and understand, 81 dB at 10 Hz and at 1 meter, is not exceptional ...

 

[Flaesh]

81 dB at 10 Hz and at 1 meter, is not exceptional

530 cm^2, 2 pi:

Almost any 12" driver can do 81 dB this way, using an integrator or two or any other equalization method.
Sorry for the 10Hz limitation. There is an online Sd-F-X-SPL calculator somewhere, you can look for it..

 

[Titurel]

I for one , don't seem to understand the design goals, I haven't read their documentation but if you could provide us with your take on it ... becasue i from what I believe I know and understand, 81 dB at 10 Hz and at 1 meter, is not exceptional ...

First, this is far from a new product. I bought mine in the '90s, so long ago I can't find review material contemporary with my purchase. It was, I believe, a product intended mostly for mastering studios, not for the living room, to allow engineers to check for unintended sub-sonics and to fine tune the eq. (I doubt many people enjoy watching their woofers dance wildly to the tune of NYC subway cars running under the recording hall.)*

I suspect the target market has shifted of late, but I don't believe the basic technology has changed. Sorry I don't have more for you. If you know anyone with a large collection pro-audio rags from the 90s, that would be a good place to hunt for more.

* Many years ago, a friend of mine recorded in a very famous New York concert hall. The session was scheduled for New's Day, between 3 and 5 a.m - one of the few long stretches when the subway wasn't running.

 

[FrantzM]

First, this is far from a new product. I bought mine in the '90s, so long ago I can't find review material contemporary with my purchase. It was, I believe, a product intended mostly for mastering studios, not for the living room, to allow engineers to check for unintended sub-sonics and to fine tune the eq. (I doubt many people enjoy watching their woofers dance wildly to the tune of NYC subway cars running under the recording hall.)*

I suspect the target market has shifted of late, but I don't believe the basic technology has changed. Sorry I don't have more for you. If you know anyone with a large collection pro-audio rags from the 90s, that would be a good place to hunt for more.

* Many years ago, a friend of mine recorded in a very famous New York concert hall. The session was scheduled for New's Day, between 3 and 5 a.m - one of the few long stretches when the subway wasn't running.

Hi

I recently recommended a subwoofer to a recording studio because of that: Low Frequencies "noises" creeping in recordings. I understand the value of subwoofers in music reproduction too, and have been an ardent proponent of subwoofers in most any system regardless of the main speakers LF extension... So I am on board here subwoofers/wise

What I would like to understand: How different Bag End models under discussion here, are from other subwoofers ? IME and I stand to be corrected, there doesn't seem to be anything special about those subwoofers in terms of performance ... It is true that some manufacturers do high pass their subwoofers and not much goes around 10 Hz but there are a plethora of subwoofers capable of substantial output at 10 Hz. There were some really innovative, designs, that were able of substantial (read, able provoke deep uncomfortable sensations) output under 20 Hz. I believe @amirm did experience this sub, and I did anyway … One of these is Bruce Thigpen so-called rotary subwoofer, that was (is?) capable of 100+ dB in-room a under 5 Hz, down to (and this, bogles my mind, and I still have some issues with the notion) to , yes, DC as in 0 Hz !!! ... There was, designed by the ever clever, unconventional and brilliant Tom Danley a subwoofer capable of "substantial " as in , way more than 81 dB at 1 meter, B: Servo Drive subwoofer. This one was used in concerts (!!!, U2, Michael Jackson) , this Servodrive subwoofer could simulate the very low and loud (for them anyway) sounds, elephants and whales use for, long distance communications ... I believe Tom Danley's company Danley Sound, still manufactures subwoofers capable of under 10 Hz at 100+ dB output for large venues., some models for HT. Yes! One of these was in Kit form, the DS-10 ... I still have the plans somewhere on a Hard Drive …

Additionally if you filter @sweetchaos , wonderful Subwoofer Comparison .. for 10 Hz, you’d find several commercially available subwoofers, that can do way more than 81 dB .. One of these the JTR is capable of 111 dB.. Cost is also sane for the performance at $5000 per unit .. The filtered list output has more than 20 sub …
one more time, kudos to @sweetchaos for this exhaustive and so useful tool ..A labor of love and I, again thank you.

My feeble aattempts:

So Bag End's claims do not seem to cut the proverbial mustard. Clever marketing. Perhaps they have models , that deliver on the Pro market , those under discussion seem, IMHO, underwhelming...

Peace.

 

[Vladimir Filevski]

One interesting function is the frequency dependedt limiter. It does exactly what bagend does, reducing load on the low frequency with rising power output.

That is totally different effect from Bag End double integrator. Limier is just squashing dynamics, double integrator preserves all dynamics.

 

[KL....]

That is totally different effect from Bag End double integrator. Limier is just squashing dynamics, double integrator preserves all dynamics.

Thank you, @Vladimir Filevski, Yes, to ask... do you know if the accurate timing (indicated in the video) suggests accurate/absolute phase/timing (ie low/very low group delay and distortion)?

The goal is uniform low-frequency extension, accurate timing, controlled response, and bass that integrates naturally with the rest of the system.

• To preserve clean reproduction and prevent structural damage during intense peaks, the system uses a built-in Dynamic Filter threshold circuit rather than harsh clipping compressors. If driven past its physical limits, the system dynamically alters the extreme low-end cutoff rather than distorting raw signals

 

[Vladimir Filevski]

So Bag End's claims do not seem to cut the proverbial mustard. Clever marketing. Perhaps they have models , that deliver on the Pro market , those under discussion seem, IMHO, underwhelming....

I think Bag End do cut the mustard, at least for their 21" model - here is measured frequency response at various SPL (test from Sound&Vision):

As we can see, Bag End S21E can reach about 98 dB at 15 Hz (and 104 dB at 20 Hz), which is very good for a sealed enclosure and a single driver. There is a reason why some manufacturers are using sealed enclosures for their subwoofers.

for 10 Hz, you’d find several commercially available subwoofers, that can do way more than 81 dB .. One of these the JTR is capable of 111 dB..Cost is also sane for the performance at $5000 per unit

Actually, max SPL output of JTR Captivator 4000-ULF is 108 dB at 10 Hz, with 20% THD. But it is a ported design and it has two 18" drivers.
From your table, there are 22 sealed box subwoofers and just 12 ported subwoofers. In general, ported subwoofers may have higher max SPL than sealed subs. But, as I said before, there is a reason why some manufactures are using sealed box subwoofers instead of ported ones. Comparing max SPL at 15 Hz for all sealed subwoofers with single driver in this table, it follows that Bag End S21E is somewhere in the middle. Not bad for a subwoofer described as "doesn't seem to be anything special".

 

[Vladimir Filevski]

Thank you, @Vladimir Filevski, to ask... do you know if the accurate timing (indicated in the video) suggest accurate/absolute phase/timing (ie low/very low group delay and distortion)?

Yes, that is true.

 

[smygolf]

Actually, max SPL output of JTR Captivator 4000-ULF is 108 dB at 10 Hz, with 20% THD. But it is a ported design and it has two 18" drivers.
From your table, there are 22 sealed box subwoofers and just 12 ported subwoofers. In general, ported subwoofers may have higher max SPL than sealed subs. But, as I said before, there is a reason why some manufactures are using sealed box subwoofers instead of ported ones. Comparing max SPL at 15 Hz for all sealed subwoofers with single driver in this table, it follows that Bag End S21E is somewhere in the middle. Not bad for a subwoofer described as "doesn't seem to be anything special".

That is at 2 met so ad 6dB