The preamble:
Covid has pretty much killed my concert season, which kind of stinks, but at least I can finally work on some purely fun stuff without distraction from PA or recording projects.
What has bubbled to the top of the to-do list is building some more muscular recreational-use subs for the farfield system in my office/studio. It is the top floor of a detached two story building 15 yards behind my house, and about 40 yards from my across-the-street neighbors.
I'm considering an infinite baffle setup, but am a little worried about the potential impact on my neighbors, and my house, for that matter.
My studio has some reasonable attempts at soundproofing (double 5/8" FR sheetrock on resilient channel, fairly limited window count), but it is wood framed, and there was only so much I could/can reasonably do.
So right now, there is audible, but not un-neighborly, leakage from the building when I'm listening at somewhat-dumb levels. What escapes is mostly low frequency.
Building bigger conventional subs presumably wouldn't make things any worse unless/until I listen louder, which is inevitable (it's kind of the point, after all ;0), but not typical.
What I don't want to do, if I build an IB sub, is go backwards, and not be able to listen even at my current levels without bugging everyone in the area.
I have lots of room, plywood, and amp power, but a somewhat pandemically-constrained driver budget. I've pretty much settled on one of two approaches:
[Safe] -- two big low-tuned vented boxes (probably double Dayton UM18-22 in approx 24 cu ft @ 16 Hz) [on sale at the moment, prompting this post].
[Easy] -- two double-18 IB manifolds... (probably 2 FiCar IB318v3 in each), shooting from my second floor studio down into my first-floor shop.
The not totally tongue-in-check question:
Which approach would likely **** off my neighbors the least?
More technically, does anybody have experience with the *net* acoustic effect outside the building when you vent an IB from a listening room into a more-or-less equivalently sized finished space above or below, as compared to getting the same results with a conventional box?
I'm thinking there is a chance that the out-of-phase back wave of an IB setup, venting from the listening room into the first floor room below *might* do two useful things:
(a) somewhat null out the listening room floor's vibrations, which would be nice for me and the room's contents
(b) turn the top and bottom floors' walls into a giant, vertically oriented dipole bass radiator, whose far-field radiation might partially null out at some distance from the building.
I'm also thinking there's a chance I'm wrong, and that the cops will show up while I'm still running the first set of REW sweeps
What do you folks think, in theory, or from experience... any chance that an IB in this configuration would have *less* net SPL some distance away from the building than a similarly-capable sealed or vented box?
My baseline is 4x NHT 1259's (12", 13mm xmax, in 2 sealed 6 cu ft boxes EQd flat to 20 in-room) borrowed from my nearfield monitor setup... sounds great at normal levels, but can't begin to keep up with the mains in the big system. I also need my monitor system back up and running.
Having subs that keep up with my mains will inevitably result in at least occasional bursts of 1AM obnoxion that are about 6-8db louder, in-room, than now.
It would be great if an IB setup was a bit better, relatively, outside the building, than a conventional setup, but really annoying if it were worse.
Any guesses, or better yet, as-built examples ?
Covid has pretty much killed my concert season, which kind of stinks, but at least I can finally work on some purely fun stuff without distraction from PA or recording projects.
What has bubbled to the top of the to-do list is building some more muscular recreational-use subs for the farfield system in my office/studio. It is the top floor of a detached two story building 15 yards behind my house, and about 40 yards from my across-the-street neighbors.
I'm considering an infinite baffle setup, but am a little worried about the potential impact on my neighbors, and my house, for that matter.
My studio has some reasonable attempts at soundproofing (double 5/8" FR sheetrock on resilient channel, fairly limited window count), but it is wood framed, and there was only so much I could/can reasonably do.
So right now, there is audible, but not un-neighborly, leakage from the building when I'm listening at somewhat-dumb levels. What escapes is mostly low frequency.
Building bigger conventional subs presumably wouldn't make things any worse unless/until I listen louder, which is inevitable (it's kind of the point, after all ;0), but not typical.
What I don't want to do, if I build an IB sub, is go backwards, and not be able to listen even at my current levels without bugging everyone in the area.
I have lots of room, plywood, and amp power, but a somewhat pandemically-constrained driver budget. I've pretty much settled on one of two approaches:
[Safe] -- two big low-tuned vented boxes (probably double Dayton UM18-22 in approx 24 cu ft @ 16 Hz) [on sale at the moment, prompting this post].
[Easy] -- two double-18 IB manifolds... (probably 2 FiCar IB318v3 in each), shooting from my second floor studio down into my first-floor shop.
The not totally tongue-in-check question:
Which approach would likely **** off my neighbors the least?
More technically, does anybody have experience with the *net* acoustic effect outside the building when you vent an IB from a listening room into a more-or-less equivalently sized finished space above or below, as compared to getting the same results with a conventional box?
I'm thinking there is a chance that the out-of-phase back wave of an IB setup, venting from the listening room into the first floor room below *might* do two useful things:
(a) somewhat null out the listening room floor's vibrations, which would be nice for me and the room's contents
(b) turn the top and bottom floors' walls into a giant, vertically oriented dipole bass radiator, whose far-field radiation might partially null out at some distance from the building.
I'm also thinking there's a chance I'm wrong, and that the cops will show up while I'm still running the first set of REW sweeps
What do you folks think, in theory, or from experience... any chance that an IB in this configuration would have *less* net SPL some distance away from the building than a similarly-capable sealed or vented box?
My baseline is 4x NHT 1259's (12", 13mm xmax, in 2 sealed 6 cu ft boxes EQd flat to 20 in-room) borrowed from my nearfield monitor setup... sounds great at normal levels, but can't begin to keep up with the mains in the big system. I also need my monitor system back up and running.
Having subs that keep up with my mains will inevitably result in at least occasional bursts of 1AM obnoxion that are about 6-8db louder, in-room, than now.
It would be great if an IB setup was a bit better, relatively, outside the building, than a conventional setup, but really annoying if it were worse.
Any guesses, or better yet, as-built examples ?
Admittedly, I have no idea about any of this, except one subtle observation about my own OB setup, which seems to provide "bass where you want it" i.e. the listening position and nowhere else.
When I was running an ordinary commercial sub, the bass seemed to propagate through the house in the typical "nothing can stop it" manner that bass does. Similar to the experience when a bass laden-automobile drives through the neighborhood; the notes seem to couple so strongly into the air around the car and then pass through structures like house walls with ease. (One just drove past, along an ajacent street as I write this...ba boom, ba boom)
I've discussed this with an engineer (far more reputable than I) without reaching a precise technical conclusion as to why this happens. He did remark listening to his system at a comfortable SPL - using 4, 18" in OB H frames - while his wife watched TV in the room below undisturbed. We agreed that this "polite" characteristic of OB speakers is beneficial for those living in closer quarters to others, at the expense of the steeped in it, in-your-face-gut-punch sealed and ported designs provide.
When I was running an ordinary commercial sub, the bass seemed to propagate through the house in the typical "nothing can stop it" manner that bass does. Similar to the experience when a bass laden-automobile drives through the neighborhood; the notes seem to couple so strongly into the air around the car and then pass through structures like house walls with ease. (One just drove past, along an ajacent street as I write this...ba boom, ba boom)
I've discussed this with an engineer (far more reputable than I) without reaching a precise technical conclusion as to why this happens. He did remark listening to his system at a comfortable SPL - using 4, 18" in OB H frames - while his wife watched TV in the room below undisturbed. We agreed that this "polite" characteristic of OB speakers is beneficial for those living in closer quarters to others, at the expense of the steeped in it, in-your-face-gut-punch sealed and ported designs provide.
Your assumption is correct regarding the dipolar nulling of an IB sub outside and perpendicular to the space.
I've got a quad 18" Fi IB318 attic mounted IB serving our primary media room. The effect outside where you're exposed to both "box" surfaces does exhibit some nulling and certainly is beneficial toward keeping the peace during high dB exploits.
Biggest issue I experienced outside was addressing small rattles here and there. Un-correlated bottom octaves aren't much an issue. But when spectral energy higher up is added then it's more noticeable.
Since few industry pros or audio enthusiasts have actually experienced an IB, I've got to tell you it's so very different in multiple ways from typical box subs. It's great, the only thing I'd do differently would be more drivers.
Curious what mains would you be mating them with?
I've got a quad 18" Fi IB318 attic mounted IB serving our primary media room. The effect outside where you're exposed to both "box" surfaces does exhibit some nulling and certainly is beneficial toward keeping the peace during high dB exploits.
Biggest issue I experienced outside was addressing small rattles here and there. Un-correlated bottom octaves aren't much an issue. But when spectral energy higher up is added then it's more noticeable.
Since few industry pros or audio enthusiasts have actually experienced an IB, I've got to tell you it's so very different in multiple ways from typical box subs. It's great, the only thing I'd do differently would be more drivers.
Curious what mains would you be mating them with?
I think your experience makes sense physically, as an OB dipole's radiation adds up to something zero-ish in the far field at LF, and has big nulls off-axis in the nearfield. I believe that jives with "bass where you want it", but without the ability to really pressurize a room at ULF, which I think == 'gut punch', and its associated structure-born vibration. I'm most certainly looking for that (the punch part).
So my thought is that an IB setup in an ideal two story building, with an IB sub pressurizing the top and bottom floors, could possibly act like a big version of an OB woofer when you're outside the building.
In practice, the construction of my space isn't fully symmetrical upstairs and down (the cathedral-ceilinged roof structure in the listening space radiates, for example, but the first floor's concrete slab doesn't. So I realize that there is no way the outdoor re-radiation is ever going to net out to zero.
But if I use an IB sub, the approximately 500 square feet of gable-end exterior wall surface that directly faces my nearest neighbor's house would be divided roughly equally between spaces with in- and out- of phase signals. Inside the rooms, at least.
If (big if) that exterior wall either become effectively transparent at LF, or if the walls at least stay in relative phase with their respective rooms' (opposite polarity) excitation signals, there might something of a null in the direction of interest.
All this could probably be modeled in SolidWorks with about $20K worth of engineering effort, but in practice I'll probably just have to build it to find out.
One thing that just hit me is that my hope that the listening room floor's forces will be nulled out is probably exactly wrong. It's a big push-pull situation. Hmmm... I think my shop's wood racks and lighting fixtures are in grave danger.
It's just too bad that an optimal IB driver isn't really an optimal vented box driver, or the penalty for being wrong would be fairly low. The Dayton UM18 supposedly works OK in either setup, but the FiCar IB18 seems to have a more appropriate Qts and 50% more xmax for the same $$$, which I would think makes it the more logical IB choice.
Typing all this is making me think it might be right risk-management strategy to buy the Daytons anyway, and add more of them later on if I do stick with IB and am underwhelmed with the output.
So my thought is that an IB setup in an ideal two story building, with an IB sub pressurizing the top and bottom floors, could possibly act like a big version of an OB woofer when you're outside the building.
In practice, the construction of my space isn't fully symmetrical upstairs and down (the cathedral-ceilinged roof structure in the listening space radiates, for example, but the first floor's concrete slab doesn't. So I realize that there is no way the outdoor re-radiation is ever going to net out to zero.
But if I use an IB sub, the approximately 500 square feet of gable-end exterior wall surface that directly faces my nearest neighbor's house would be divided roughly equally between spaces with in- and out- of phase signals. Inside the rooms, at least.
If (big if) that exterior wall either become effectively transparent at LF, or if the walls at least stay in relative phase with their respective rooms' (opposite polarity) excitation signals, there might something of a null in the direction of interest.
All this could probably be modeled in SolidWorks with about $20K worth of engineering effort, but in practice I'll probably just have to build it to find out.
One thing that just hit me is that my hope that the listening room floor's forces will be nulled out is probably exactly wrong. It's a big push-pull situation. Hmmm... I think my shop's wood racks and lighting fixtures are in grave danger.
It's just too bad that an optimal IB driver isn't really an optimal vented box driver, or the penalty for being wrong would be fairly low. The Dayton UM18 supposedly works OK in either setup, but the FiCar IB18 seems to have a more appropriate Qts and 50% more xmax for the same $$$, which I would think makes it the more logical IB choice.
Typing all this is making me think it might be right risk-management strategy to buy the Daytons anyway, and add more of them later on if I do stick with IB and am underwhelmed with the output.
FOH, thank you for your input, your encouragement will probably get me un-waffled enough to go the Fi318 route. I'm curious... do you have the "V2" version of the Fi, and... do they bottom gracefully? I've been hoping to run without a HPF and was wondering how that works in practice.
Re: my mains, etc... now I'll derail my own thread.
What's sitting in the end of the room right now is a crazy kludge three-way that I put together to test a new mid for an evolution of my current medium-room PA tops, and to start working my way through a FIR tuning workflow with rePhase, REW, and my Symetrix processors.
I wound up liking it so much that I haven't broken it down to build real cabinets yet... and with no gigs (sigh), I haven't had to. Really ugly looking (see attached), but lately there is hardly anyone here to notice.
The HF is a Stage Accompany SA8535, the mids are the JBL 8" CMCD in the 90x60 small-format PT horn, and the midbass is a JBL 2265HPL. The old mid (seen lying sideways in the photo, donating its midbass to the test) was a RCFMR8N301 in their H6000 horn. I like the CMCD much better. The MF/HF crossover is a semi-steep complimentary FIR implementation at 1800Hz. The MB/MF crossover is at 340, too low for the Jupiter's 512 tap FIR filters, but I do some phase flattening. I haven't lugged these outdoors for testing, but indoors, the MF/HF transition is pretty much lobe-less vertically, much better than anything I've ever achieved with the SA tweeter before.
I have some powered Danley SM60-F's whose magic polar behavior make them a silver bullet at certain gigs, but these new tops sound much better on-axis, or near it, and are much more relaxed sounding at elevated SPLs.
That said, I'm getting increasingly adamant about not lugging any of my PA gear up and down my stairs, so there is a (hopefully) thread-worthy 3-way line array going up in this end of the room fairly soon. Drivers are on hand, but there is some more room reconfiguration required first to make space. I figure I'd start with some subwoofers to put under it.
The amp rack that is driving this right now is also poached from my mid-field monitors, which is a Symetrix Jupiter 8 DSP and 4 of the analog-input Lab Gruppen E-series amps of various sizes (600/ch for the SW, 400 for the MB, 200/ch for the CMCD, and 100/ch for the SA8535). The LG amps are not quiet enough to stay in the room forever, but tolerable for now. The poor little NHT 1259s run out of excursion right when the LG E12:2 runs out of juice, which is lucky, as I've wrecked several of them over the years with really brief mistakes with bigger amps. I'm down to my last 4, so I really need to stop (ab)using them in this application ASAP.
The rack that is supposed to be running this system usually runs the mains at gigs. Its fans are way too loud for it to be in the room, so it is banished until I finish running more AWG10 wire from the load-in bay downstairs up to the upstairs speaker position.
It uses a Symetrix Radius 12x8 for DSP (open architecture, Dante, longer FIR filters), and is populated with 2x PowerSoft 5204 2ch amps (ca. 2500W/ch), for subs & MB, and a PowerSoft 1204 4ch amp (300W/ch) for the mids and HF. It's a bit too much gain for home levels, but I can't afford to put together another multiway rack right now.
Re: my mains, etc... now I'll derail my own thread.
What's sitting in the end of the room right now is a crazy kludge three-way that I put together to test a new mid for an evolution of my current medium-room PA tops, and to start working my way through a FIR tuning workflow with rePhase, REW, and my Symetrix processors.
I wound up liking it so much that I haven't broken it down to build real cabinets yet... and with no gigs (sigh), I haven't had to. Really ugly looking (see attached), but lately there is hardly anyone here to notice.
The HF is a Stage Accompany SA8535, the mids are the JBL 8" CMCD in the 90x60 small-format PT horn, and the midbass is a JBL 2265HPL. The old mid (seen lying sideways in the photo, donating its midbass to the test) was a RCFMR8N301 in their H6000 horn. I like the CMCD much better. The MF/HF crossover is a semi-steep complimentary FIR implementation at 1800Hz. The MB/MF crossover is at 340, too low for the Jupiter's 512 tap FIR filters, but I do some phase flattening. I haven't lugged these outdoors for testing, but indoors, the MF/HF transition is pretty much lobe-less vertically, much better than anything I've ever achieved with the SA tweeter before.
I have some powered Danley SM60-F's whose magic polar behavior make them a silver bullet at certain gigs, but these new tops sound much better on-axis, or near it, and are much more relaxed sounding at elevated SPLs.
That said, I'm getting increasingly adamant about not lugging any of my PA gear up and down my stairs, so there is a (hopefully) thread-worthy 3-way line array going up in this end of the room fairly soon. Drivers are on hand, but there is some more room reconfiguration required first to make space. I figure I'd start with some subwoofers to put under it.
The amp rack that is driving this right now is also poached from my mid-field monitors, which is a Symetrix Jupiter 8 DSP and 4 of the analog-input Lab Gruppen E-series amps of various sizes (600/ch for the SW, 400 for the MB, 200/ch for the CMCD, and 100/ch for the SA8535). The LG amps are not quiet enough to stay in the room forever, but tolerable for now. The poor little NHT 1259s run out of excursion right when the LG E12:2 runs out of juice, which is lucky, as I've wrecked several of them over the years with really brief mistakes with bigger amps. I'm down to my last 4, so I really need to stop (ab)using them in this application ASAP.
The rack that is supposed to be running this system usually runs the mains at gigs. Its fans are way too loud for it to be in the room, so it is banished until I finish running more AWG10 wire from the load-in bay downstairs up to the upstairs speaker position.
It uses a Symetrix Radius 12x8 for DSP (open architecture, Dante, longer FIR filters), and is populated with 2x PowerSoft 5204 2ch amps (ca. 2500W/ch), for subs & MB, and a PowerSoft 1204 4ch amp (300W/ch) for the mids and HF. It's a bit too much gain for home levels, but I can't afford to put together another multiway rack right now.
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Tonyman108,
I agree with you and FOH that the IB should result in less exterior propagation, but considering as you have plenty of gear (and unfortunately, time off), I'd suggest some actual tests to confirm the theory.
You could "simply" prop up a sub on a pair of ladders, (or a crank lift if you have one) in the position you plan for the IB, drive another upstairs in the same position in reverse polarity, and measure outdoors at various positions around the property line.
Also a good test to determine the best placement before cutting holes...
Pink noise is far more stealthy than swept tones for outdoor testing ;^).
If the IB does turn out to be less offensive elsewhere, to address the shake problem, mounting the drivers horizontally opposed in a plenum would provide force cancellation, and eliminate cone sag. Push-pull or push-push could be used, and the exit hole could be fairly small, probably no more than the SD of one cone for four would be needed.
Art
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I guess that depends on exactly which millisecond you make me answer the question ;0)
Lame humor aside, that was a fair call-out of imprecise language. How about... "a dipole radiator in a reasonable sized baffle will probably have a far field power response that rolls off with decreasing frequency faster than an IB system or a huge closed-box subwoofer". I.E., probably not the best bet for blurring your vision with ULF reproduction.
As I'm sure you know, kick drums, and even tympanis, etc, aren't particularly ULF devices, unless/until some recording/mixing engineer starts going nuts with the signal.
But drums do have front and back waves, and given the discussion's general theme of back-wave cancellation, I was curious why a kick drum does make decent energy at 50-60Hz or so even though that is a pretty a pretty long wavelength in comparison to their dimensions. I had my suspicions, and my quick reads on the topic partially confirmed them, but also showed that drums are an even more complicated resonant (and psychoacousic) system than I'd realized, so I think I'll just stop there and read more instead of write.
Thank you, Art, that is a fabulous suggestion! I don't have an appropriate lift, but that doesn't kill the idea.
The NHT cabinets weigh 125 lbs. I could probably get that up on some ladders without dying, but it looks like I can rent a lift from my local Home Depot with a 12' rise and a 450 lb. capacity for $70 a day, or $49 if I can stage the test in 4 hours or less.
It might take a while to find the right time window, but that seems like a pretty good investment.
Re: the horizontally-opposed manifold idea... definitely what I was planning on doing. I truly wish it was with opposed pairs of SI IB24s, but maybe later...
I just have a pair of 18 inch woofers configured IB into the ceiling of the front house. Also I have an air vent in the back of the attic. It really does not seem to have much VLF leakage from outside but you may also be playing at another SPL level compared to me.
I do not have anyone living close to the back of the house for maybe 200 feet so I do not have to worry.
The kids are getting older and I can see my daughter pushing things a little farther than I do. She just has to operate it within the limits of the house.
IB of this sort is really worth it. Just a bit less effort for the woofers and amplifiers.
I do not have anyone living close to the back of the house for maybe 200 feet so I do not have to worry.
The kids are getting older and I can see my daughter pushing things a little farther than I do. She just has to operate it within the limits of the house.
IB of this sort is really worth it. Just a bit less effort for the woofers and amplifiers.
Been pondering this some more.
A vented, low tuned sub compared to an IB is really the classic apples-to-oranges comparison.
I'd say subjectively the output capabilities are 4-to-1. Wheras a single, well executed vented 18" would subjectively output equally as well as (4)18"s in an IB. Just so difficult to compare. They both exhibit a very different resultant sound.
Much easier to compare would be a typical small sealed sub compared to an IB. In that case the primary differentiating factor is the power requirements. I'd estimate a 10/1 difference comparing a driver in a small sealed, to that driver in an IB alignment. It just doesn't take much power to achieve full stroke when it's not compressing that backspace. This dramatic lowering of power positively effects the amplifier(s) and the circuit feeding them.
For example a high power small sealed subwoofer system (multiples) can demand huge amounts of current for transients.
With Linkwitz Transform signal shaping in place, a single high performance sealed sub can easily require 2kw-4kw or more for the bottom octaves. Throw transients atop the deep stuff and multiple subs you're encountering AC current levels well above the 20amp point. These peak demands are met with voltage drop back to the panel.
I realize this is quite the savvy group here, but it's worth repeating.
To prevent nuisance tripping, a 20amp circuit breaker will pass huge amounts of current;
Over 100a for up to a second
~60a for about 10 seconds
~30-40a for as long as 30 seconds!
Home theater type infra effects need massive amounts of power.
Point being an IB's low operational power side steps all those high power choke point.
Since it only requires about 250w or so to hit full stroke, amplifier demands are quite modest.
No dynamics limiting voltage drop feeding the amp.
Very little thermal compression.
Stays away from the high current flux modulation distortions; Le(i).
BUT, there's been a handful of IB builds whereby the final sound just wasn't what the DIY'er was after.
It's subjectively not like four 18s pounding away. If I had to characterize it it's akin to a single 18 with the most effortless and smooth extension down into the single digits.
Unless you high pass it and EQ some guttural punch into the response, it's not going to be like a quad set of 18s.
I think it's great that you'd be using some mid-bass units, but not sure how low you're bringing those. In my experience, unless you've got 8-18s, its hard to cover the infra-range and cover all the way up solidly into the visceral punch region 60hz-80hz.
Four octaves (5-80) is a HUGE ask for a driver... unless of course you keep excursion way down by multiples.
Each octave lower requires 4x the stroke.
Myself, I augment my IB with two, double 15 small sealed (two Seaton SubMersives). They're each powered by 4kw SpeakerPower plate amp.
My everyday driver family rig, from 200hz downward, I'm utilizing (6)12"s, (4)15"s, and the IB(4)18's, in our 28'x13'x8' family room/kitchen in the back.
I could easily use four more IB 18"s.
To answer your question, no mine don't bottom nicely, currently they're slightly power limited ... but wide open, no high pass.
Just explore their excursion limits open air prior to install. Perform these tests with the entire signal path if possible. Each piece of gear's -3dB point can add up down deep. Plus exploring the limits open air is a lot more tolerable than shaking your entire structure! (Full stroke test tones my ceiling "breathes maybe 2" or so, before additional bracing).
I hope that helps, I know that's a lot off topic.
A vented, low tuned sub compared to an IB is really the classic apples-to-oranges comparison.
I'd say subjectively the output capabilities are 4-to-1. Wheras a single, well executed vented 18" would subjectively output equally as well as (4)18"s in an IB. Just so difficult to compare. They both exhibit a very different resultant sound.
Much easier to compare would be a typical small sealed sub compared to an IB. In that case the primary differentiating factor is the power requirements. I'd estimate a 10/1 difference comparing a driver in a small sealed, to that driver in an IB alignment. It just doesn't take much power to achieve full stroke when it's not compressing that backspace. This dramatic lowering of power positively effects the amplifier(s) and the circuit feeding them.
For example a high power small sealed subwoofer system (multiples) can demand huge amounts of current for transients.
With Linkwitz Transform signal shaping in place, a single high performance sealed sub can easily require 2kw-4kw or more for the bottom octaves. Throw transients atop the deep stuff and multiple subs you're encountering AC current levels well above the 20amp point. These peak demands are met with voltage drop back to the panel.
I realize this is quite the savvy group here, but it's worth repeating.
To prevent nuisance tripping, a 20amp circuit breaker will pass huge amounts of current;
Over 100a for up to a second
~60a for about 10 seconds
~30-40a for as long as 30 seconds!
Home theater type infra effects need massive amounts of power.
Point being an IB's low operational power side steps all those high power choke point.
Since it only requires about 250w or so to hit full stroke, amplifier demands are quite modest.
No dynamics limiting voltage drop feeding the amp.
Very little thermal compression.
Stays away from the high current flux modulation distortions; Le(i).
BUT, there's been a handful of IB builds whereby the final sound just wasn't what the DIY'er was after.
It's subjectively not like four 18s pounding away. If I had to characterize it it's akin to a single 18 with the most effortless and smooth extension down into the single digits.
Unless you high pass it and EQ some guttural punch into the response, it's not going to be like a quad set of 18s.
I think it's great that you'd be using some mid-bass units, but not sure how low you're bringing those. In my experience, unless you've got 8-18s, its hard to cover the infra-range and cover all the way up solidly into the visceral punch region 60hz-80hz.
Four octaves (5-80) is a HUGE ask for a driver... unless of course you keep excursion way down by multiples.
Each octave lower requires 4x the stroke.
Myself, I augment my IB with two, double 15 small sealed (two Seaton SubMersives). They're each powered by 4kw SpeakerPower plate amp.
My everyday driver family rig, from 200hz downward, I'm utilizing (6)12"s, (4)15"s, and the IB(4)18's, in our 28'x13'x8' family room/kitchen in the back.
I could easily use four more IB 18"s.
To answer your question, no mine don't bottom nicely, currently they're slightly power limited ... but wide open, no high pass.
Just explore their excursion limits open air prior to install. Perform these tests with the entire signal path if possible. Each piece of gear's -3dB point can add up down deep. Plus exploring the limits open air is a lot more tolerable than shaking your entire structure! (Full stroke test tones my ceiling "breathes maybe 2" or so, before additional bracing).
I hope that helps, I know that's a lot off topic.
Tonyman, my mains are OB and delightful and I have more recently enhanced the low end (about 50Hz and lower) with a 6 inch driver in a tapped folded horn. The horn is coupled using approx 20mH air core "crossover". The value was determined empirically to suit my hearing. The result is almost as good as a live concert.
Indeed, they have sub harmonics that go down to 7-8 Hz. Tom Danley showed us an even more complex one, a car door slam with sub harmonics down to 2 Hz IIRC.
GM
Note to everyone wondering about the question posed in the thread title... I've been looking at the logistics, and am almost certainly going to be able to make the part-scale in-situ measurements that Art suggested.
It's my wife's [mumble]'th birthday this weekend, but hopefully next week.
I was just looking at the first-floor space below the proposed IB site, and all the tools that would interfere with hoisting a second subwoofer up to the ceiling are on wheels, and there is only one wood rack in the way.
Now to slip further down the slope towards a design/build thread:
That all makes sense. I'd say "logarithms are a bitch", but I don't believe the forum's censor-bot will let my type "bitch". Whops... it did!
I'm not hugely worried about they system underperforming. If (as is looking increasingly likely) I go with an IB sub it will be easily scalable. I am planning to put the manifolds in the listening room, but I can fairly easily accommodate 4 of them spaced along the 'target wall' without it getting too intrusive.
Luckily, I have an in-room baseline system, I know the current subs' raw mathematical limits, and I know when it runs out of gas.
My repurposed 4x12 NHT sealed subs are flat to 20, and have a combined within-xmax displacement of approx 4x450x0.13=234cc
4x 18" Fi318 with (if it can be believed??) 39mm xmax is 4x1210x0.39=1888cc
If FI is telling the truth, and I'm doing my math correctly, that represents a 9db improvement in displacement-limited SPL over what I'm currently listening to.
When I listen to music with the system as-is, I can see where my master fader is when I'm thinking "I really shouldn't be doing this to my ears", and also know how much I have to turn it down from that point when some bass-heavy program material comes along and I think (or smell) "I really shouldn't be doing this to my last 4 NHT 1259s".
Encouragingly, the spread between those two fader positions is about 6 db.
Yes, this is highly program dependent. +9dB worth of extra bass headroom may or may not be enough to handle a demo track with some crazy ULF content at arbitrary levels, but it will absolutely handle 99.5% of my music listening needs. If not, you have to admit it slots pretty firmly into the "first world problem" category!
Not to say I am in any way immune to the urge to play around with silly demo material. If you have a minute, see this archive someone has kept of a very old rec.audio post of mine: https://histandard.info/~john/humor/jets.crickets
Sorry for the twenty year old typos, btw. It is way off topic from the farfield effect of IB subwoofers, but completely relevant to the general topic of bothering your neighbors with your sound system ;0) I'm a little more mature now than I was then, but not *that* much. But I do have roots in my community now, and I obviously didn't back then.
Egad!
LF/MB crossover is currently 80Hz between the NHTs and the JBL 15 in the temporary system.
As to the midbass section of the F-T-C line array that will take its place... TBD. It needs modeling and experimentation, but the crossover probably will wind up a bit lower.
The plans for that system have evolved several times. It was originally going to be semi-portable, but now isn't, it was going to be a 2-way built around $9000 worth of SA 8535 tweeters, but I decided to send my kids to college instead. So now it is a 3-way built around a more affordable pile of BG Neo 3PDRs and an even bigger pile of Seas H453 4" cone midranges.
As a result, my driver hoard contains two midbass options... I think I still have 42 of the original choice: the 6.5" Foster-manufactured midbass drivers NHT used in the 3.3. Those have a low FS, worked well in a small sealed enclosure, have a nice extended midrange response, but only have a 3.5mm xmax. With available vertical space and a reserve for spares, I could use 18 per side in a double row.
The more likely choice is the 32 Aura NS-8 woofers I also have on hand. They have a 6mm xmax, and I'm pretty sure they'll work well up to the intended 300-ish hz midrange crossover point, but will try a scale model soon to be sure. I think can just fit a single row of a dozen of these in the height available where my (@!#$%%$) sloped ceiling intersects the planned installation point.
My gut tells me that if I'm happy with a single 15" sealed midbass now, I would be at least equally happy with 12 8" sealed midbasses (it would have 50% more swept volume vs. the JBL). Still, if I want a lower crossover to the subs I think I'll use Vituix to model the cabinet choices. I might need the extra output of a vented cabinet tuned down near 50-60Hz.
It's my wife's [mumble]'th birthday this weekend, but hopefully next week.
I was just looking at the first-floor space below the proposed IB site, and all the tools that would interfere with hoisting a second subwoofer up to the ceiling are on wheels, and there is only one wood rack in the way.
Now to slip further down the slope towards a design/build thread:
That all makes sense. I'd say "logarithms are a bitch", but I don't believe the forum's censor-bot will let my type "bitch". Whops... it did!
I'm not hugely worried about they system underperforming. If (as is looking increasingly likely) I go with an IB sub it will be easily scalable. I am planning to put the manifolds in the listening room, but I can fairly easily accommodate 4 of them spaced along the 'target wall' without it getting too intrusive.
Luckily, I have an in-room baseline system, I know the current subs' raw mathematical limits, and I know when it runs out of gas.
My repurposed 4x12 NHT sealed subs are flat to 20, and have a combined within-xmax displacement of approx 4x450x0.13=234cc
4x 18" Fi318 with (if it can be believed??) 39mm xmax is 4x1210x0.39=1888cc
If FI is telling the truth, and I'm doing my math correctly, that represents a 9db improvement in displacement-limited SPL over what I'm currently listening to.
When I listen to music with the system as-is, I can see where my master fader is when I'm thinking "I really shouldn't be doing this to my ears", and also know how much I have to turn it down from that point when some bass-heavy program material comes along and I think (or smell) "I really shouldn't be doing this to my last 4 NHT 1259s".
Encouragingly, the spread between those two fader positions is about 6 db.
Yes, this is highly program dependent. +9dB worth of extra bass headroom may or may not be enough to handle a demo track with some crazy ULF content at arbitrary levels, but it will absolutely handle 99.5% of my music listening needs. If not, you have to admit it slots pretty firmly into the "first world problem" category!
Not to say I am in any way immune to the urge to play around with silly demo material. If you have a minute, see this archive someone has kept of a very old rec.audio post of mine: https://histandard.info/~john/humor/jets.crickets
Sorry for the twenty year old typos, btw. It is way off topic from the farfield effect of IB subwoofers, but completely relevant to the general topic of bothering your neighbors with your sound system ;0) I'm a little more mature now than I was then, but not *that* much. But I do have roots in my community now, and I obviously didn't back then.
Egad!
LF/MB crossover is currently 80Hz between the NHTs and the JBL 15 in the temporary system.
As to the midbass section of the F-T-C line array that will take its place... TBD. It needs modeling and experimentation, but the crossover probably will wind up a bit lower.
The plans for that system have evolved several times. It was originally going to be semi-portable, but now isn't, it was going to be a 2-way built around $9000 worth of SA 8535 tweeters, but I decided to send my kids to college instead. So now it is a 3-way built around a more affordable pile of BG Neo 3PDRs and an even bigger pile of Seas H453 4" cone midranges.
As a result, my driver hoard contains two midbass options... I think I still have 42 of the original choice: the 6.5" Foster-manufactured midbass drivers NHT used in the 3.3. Those have a low FS, worked well in a small sealed enclosure, have a nice extended midrange response, but only have a 3.5mm xmax. With available vertical space and a reserve for spares, I could use 18 per side in a double row.
The more likely choice is the 32 Aura NS-8 woofers I also have on hand. They have a 6mm xmax, and I'm pretty sure they'll work well up to the intended 300-ish hz midrange crossover point, but will try a scale model soon to be sure. I think can just fit a single row of a dozen of these in the height available where my (@!#$%%$) sloped ceiling intersects the planned installation point.
My gut tells me that if I'm happy with a single 15" sealed midbass now, I would be at least equally happy with 12 8" sealed midbasses (it would have 50% more swept volume vs. the JBL). Still, if I want a lower crossover to the subs I think I'll use Vituix to model the cabinet choices. I might need the extra output of a vented cabinet tuned down near 50-60Hz.
Hi guys. I've got a bit of data... and it is not entirely pretty!
As promised, I have done my best to run the experiment proposed by Art, where I stuck an out-of-phase sub up near the ceiling (directly below another copy of said sub in the listening room), and measure what happens, indoors and out.
I decided to do this with a pair of JBL618-XLF powered subs, as they are much easier to move than my NHTs, play much louder, and are less likely to be damaged by an errant button-push during the experiments.
Only downside is that they have much less LF bandwidth, being a vented design with an F3 of 38Hz. Still, kind of interesting results, and I'm glad I did it.
I've attached a photo of the precarious rig for the downstairs woofer (the one located where the back-wave of one of the IB sub manifolds will vent). The racking I had on hand was too short to get the sub all the way to the ceiling, hence the use of multiple, uh, "cylindrical height augmentation units". I couldn't locate sufficient chewing gum or baling wire, so I substituted gaffer's tape and ratchet straps.
Before we move on, I have a quick favor to ask... can someone get to work on the Darwin Award nomination paperwork for me, just in case I can't do myself after my buddy and I attempt to take this down?
Anyway, the setup is as follows... OmniMic test tones (pseudo-noise) playing via a hardware player to a mixer, the mono signal was split to two Aux sends. This let me use the mixer's iPad app to selectively mute the upstairs and polarity-reversed "downstairs" subwoofer feeds from anywhere within a few hundred feet of the house or the studio building.
I level-matched the two subs, and flipped the polarity on one, then we hoisted it up to the ceiling. The relative and absolute levels remained unchanged during the session.
Using the hardware streamer for the excitation signals' playback freed up my DAW laptop to portably run the OmniMic software from outside the building.
I've attached a few snapshots from the OmniMic, with various sets of measurements taken indoors at the listening position, and some outdoors. The outdoors measurements are very contaminated by wind and other ambient noise... I'll try to get a cleaner set when the wind, traffic, and neighbors allow for it.
The JBLs, measured outdoors on the ground, are very flat in their passband. In-room response wasn't horrible, I didn't EQ out the lumps. Perhaps should have.
First, the indoor measurements. In the proposed IB setup, the floor of the listening room will be (anti-) excited by the IB's backwave. There are other possible transmission paths as well, as the first floor is above-grade with wood framed walls.
I have been wondering whether the leakage from the first floor up to the listening room would do anything measurable to the response. Short answer... yes. But it is fairly subtle, and isn't all negative.
Looking at the 'upstairs measurements' snapshot, the yellow trace is taken at the listening position with only the upstairs sub active. The red trace is with only the downstairs sub active, and the black trace is with both active.
By ear, the difference in tone when muting the 'downstairs' subwoofer is audible with pink-ish noise playing, but hardly dramatic, especially at the main listening position. While the response varies from place to place in the room, I haven't found any spot where activating the downstairs sub makes a hugely audioble difference.
I find the giant suckout at 55 hz on top of the ca. 20 db of attenuation of the 'downstairs' signal (the red trace) to be quite interesting. The shop ceiling has 5/8" sheetrock on RC, I'm wondering if 55Hz is the resonant frequency of that system. The ceiling of my listening room is similarly constructed, and i happen to have a lot of weirdnesses in my room at 50-60 hz. Might be an area for further study; I'd assumed it was all due to room dimensions, but perhaps my celling is acting like a giant 55Hz bass trap as well.
Anyway, the outdoor measurements were the motivation behind this experiment, and I have to say... my initial fears were well founded. The studio was built (at least after the fact) with sound isolation in mind. The shop was not. It shows.
The 'outdoors' measurement set was taken from a point about 15' away from the gable end wall of the building, with the mic about 10' in the air, approximately at the studio's floor height. This happens to be in the same direction, and the same height, as my neighbor's first floor living room windows.
The green trace was collected with only the upstairs sub active, roughly equivalent to my current system, minus the bottom octave. The measured SPL (not show) right at the inside surface of the wall was 125db, and was 105 db at the listening position, 13' away. Outside, it averaged 68db. Not too bad.
Unfortunately, as can be seen from the blue trace, the leakage from the downstairs sub taken alone, is 10db louder.
And... with both of them running, you can see (and just barely hear) that some cancellation is taking place over some of the frequencies of interest, but not huge. This makes sense as the two signals aren't the same amplitude.
As far as what this extra leakage means to a human inside a nearby building... yeah, you can absolutely hear the difference, and it is about as un-subtle as you'd expect 10db to be.
I was sitting in my living room late last night reading a book on my iPad. The traffic and wind were finally calm. I realized that the mixer remote app was still running, and that the test signals were still looping. I had a what-the-heck moment, and fired up the 'studio-only' subwoofer. I could just barely hear it. Adding the downstairs signal, it was distressingly audible. It's about 75' from there to the gable end wall of the studio. My nearest neighbor is across the road, about 45' further away.
Ah well. I've ordered the drivers and am building the IB system anyway.
I'll do what I can to tighten up the shop, acoustically, but I can sense a new thread coming soon... "Active Noise Cancellation for my Noisy Building"
As promised, I have done my best to run the experiment proposed by Art, where I stuck an out-of-phase sub up near the ceiling (directly below another copy of said sub in the listening room), and measure what happens, indoors and out.
I decided to do this with a pair of JBL618-XLF powered subs, as they are much easier to move than my NHTs, play much louder, and are less likely to be damaged by an errant button-push during the experiments.
Only downside is that they have much less LF bandwidth, being a vented design with an F3 of 38Hz. Still, kind of interesting results, and I'm glad I did it.
I've attached a photo of the precarious rig for the downstairs woofer (the one located where the back-wave of one of the IB sub manifolds will vent). The racking I had on hand was too short to get the sub all the way to the ceiling, hence the use of multiple, uh, "cylindrical height augmentation units". I couldn't locate sufficient chewing gum or baling wire, so I substituted gaffer's tape and ratchet straps.
Before we move on, I have a quick favor to ask... can someone get to work on the Darwin Award nomination paperwork for me, just in case I can't do myself after my buddy and I attempt to take this down?
Anyway, the setup is as follows... OmniMic test tones (pseudo-noise) playing via a hardware player to a mixer, the mono signal was split to two Aux sends. This let me use the mixer's iPad app to selectively mute the upstairs and polarity-reversed "downstairs" subwoofer feeds from anywhere within a few hundred feet of the house or the studio building.
I level-matched the two subs, and flipped the polarity on one, then we hoisted it up to the ceiling. The relative and absolute levels remained unchanged during the session.
Using the hardware streamer for the excitation signals' playback freed up my DAW laptop to portably run the OmniMic software from outside the building.
I've attached a few snapshots from the OmniMic, with various sets of measurements taken indoors at the listening position, and some outdoors. The outdoors measurements are very contaminated by wind and other ambient noise... I'll try to get a cleaner set when the wind, traffic, and neighbors allow for it.
The JBLs, measured outdoors on the ground, are very flat in their passband. In-room response wasn't horrible, I didn't EQ out the lumps. Perhaps should have.
First, the indoor measurements. In the proposed IB setup, the floor of the listening room will be (anti-) excited by the IB's backwave. There are other possible transmission paths as well, as the first floor is above-grade with wood framed walls.
I have been wondering whether the leakage from the first floor up to the listening room would do anything measurable to the response. Short answer... yes. But it is fairly subtle, and isn't all negative.
Looking at the 'upstairs measurements' snapshot, the yellow trace is taken at the listening position with only the upstairs sub active. The red trace is with only the downstairs sub active, and the black trace is with both active.
By ear, the difference in tone when muting the 'downstairs' subwoofer is audible with pink-ish noise playing, but hardly dramatic, especially at the main listening position. While the response varies from place to place in the room, I haven't found any spot where activating the downstairs sub makes a hugely audioble difference.
I find the giant suckout at 55 hz on top of the ca. 20 db of attenuation of the 'downstairs' signal (the red trace) to be quite interesting. The shop ceiling has 5/8" sheetrock on RC, I'm wondering if 55Hz is the resonant frequency of that system. The ceiling of my listening room is similarly constructed, and i happen to have a lot of weirdnesses in my room at 50-60 hz. Might be an area for further study; I'd assumed it was all due to room dimensions, but perhaps my celling is acting like a giant 55Hz bass trap as well.
Anyway, the outdoor measurements were the motivation behind this experiment, and I have to say... my initial fears were well founded. The studio was built (at least after the fact) with sound isolation in mind. The shop was not. It shows.
The 'outdoors' measurement set was taken from a point about 15' away from the gable end wall of the building, with the mic about 10' in the air, approximately at the studio's floor height. This happens to be in the same direction, and the same height, as my neighbor's first floor living room windows.
The green trace was collected with only the upstairs sub active, roughly equivalent to my current system, minus the bottom octave. The measured SPL (not show) right at the inside surface of the wall was 125db, and was 105 db at the listening position, 13' away. Outside, it averaged 68db. Not too bad.
Unfortunately, as can be seen from the blue trace, the leakage from the downstairs sub taken alone, is 10db louder.
And... with both of them running, you can see (and just barely hear) that some cancellation is taking place over some of the frequencies of interest, but not huge. This makes sense as the two signals aren't the same amplitude.
As far as what this extra leakage means to a human inside a nearby building... yeah, you can absolutely hear the difference, and it is about as un-subtle as you'd expect 10db to be.
I was sitting in my living room late last night reading a book on my iPad. The traffic and wind were finally calm. I realized that the mixer remote app was still running, and that the test signals were still looping. I had a what-the-heck moment, and fired up the 'studio-only' subwoofer. I could just barely hear it. Adding the downstairs signal, it was distressingly audible. It's about 75' from there to the gable end wall of the studio. My nearest neighbor is across the road, about 45' further away.
Ah well. I've ordered the drivers and am building the IB system anyway.
I'll do what I can to tighten up the shop, acoustically, but I can sense a new thread coming soon... "Active Noise Cancellation for my Noisy Building"
Attachments
Good work, Tonyman!
Have to say that finding the leakage from the downstairs sub being 10db louder than the upstairs was a surprise to me, had you tested that first, could have eliminated the reverse polarity Darwin Award lift portion of the test.
You have scientifically confirmed you are building the wrong choice regarding LF sound leakage to the neighbors
.Cheers,
Art
I was a somewhat surprised myself... I was guessing 6 dB. I built the building back when my wife and I still owned the property with another couple. There were substantial budget compromises made; as we were splitting the cost. We were mostly focused on the shop space's size and function (we had a paying tenant in hand).
For 20 years it has all belonged to my wife and I, but I'm still stuck with some of those 25 year-old cost cutting decisions. I fixed as many things as I could when finishing out the studio space in the 00's (sadly, I didn't raise the roof ;0), but the first floor is a sound isolation mess.
The bottom story's walls are insulated, but the (really stiff) recycled cement/drywall/woodpulp drywall material is directly screwed to the 2x6 studs. Only the ceiling is on RC there. Upstairs, the (double-thick) walls and (single-thick) ceiling all float, and I was pretty fussy about not bridging anything over to the framing.
The shop's gable end wall also has two sets of big site-built barn-style double doors. We tried hard when building these, and built them vert heavily, but in the end might as well have made them out of cheesecloth, acoustically. I can't stud over them as I need to maintain the ability to move heavy tools in and out of the shop from time to time. Long ago I built removable, and fairly airtight, floating inner door panels. These were built with drafts in mind, not sound. I clearly need to make a new set of panels that are much stiffer, and more carefully isolated from the outer doors.
Re: the attempted Darwin award... I actually did a quickie version of the test with the sub on the floor almost a week ago, and knew what I was getting into before ordering the drivers and then documenting the exact extent of my antisocial choice. Hey, I promised measurements!
Speaking of which, I'll do more tests with the real IB system later. Obviously won't be able to turn the reverse wave on and off, but I can compare the whole thing to my other subs. Also really curious to see if the building turns out to be really transparent to ULF.
About building the IB system even though I know it will be a potential annoyance:
After thinking about it a lot more, I decided I was... overthinking it.
I've heard IB systems elsewhere, and I really want to have that infra-bass experience on tap. If I have to restrict demo-level listening of the big system to reasonable hours, so be it.
On the occasions that I feel the need to listen to loud music late at night, I can probably manage to summon the energy it takes to walk the whole 8 feet required so I can plop down in the "Maxwell Guy" listening chair behind my mix position, and listen to my mid-field monitors instead.
That is normally what the sealed NHT subs are attached to, and in that spot, from that chair, they have plenty of output.
That said, I wasn't entirely kidding about the active noise cancellation idea. The Symetrix Radius I use for the main system's crossover has Dante, and I have both the DSP horsepower and enough Dante-enabled output channels (and amps) available to let me hook some Aurasound tactile transducers into the system. The thought was to bolt several of them to the inside of those barn-doors, feed them an appropriately filtered signal, and turn the doors into great big anti-woofers.
It would be a funny and relatively inexpensive stunt to attempt, and might even work. I promise that if I ever get around to trying it, I'll let you guys know.
More pressingly, I have to ask everyone for help on where to position the new IB system. New thread, I've already bloated this one enough.
For 20 years it has all belonged to my wife and I, but I'm still stuck with some of those 25 year-old cost cutting decisions. I fixed as many things as I could when finishing out the studio space in the 00's (sadly, I didn't raise the roof ;0), but the first floor is a sound isolation mess.
The bottom story's walls are insulated, but the (really stiff) recycled cement/drywall/woodpulp drywall material is directly screwed to the 2x6 studs. Only the ceiling is on RC there. Upstairs, the (double-thick) walls and (single-thick) ceiling all float, and I was pretty fussy about not bridging anything over to the framing.
The shop's gable end wall also has two sets of big site-built barn-style double doors. We tried hard when building these, and built them vert heavily, but in the end might as well have made them out of cheesecloth, acoustically. I can't stud over them as I need to maintain the ability to move heavy tools in and out of the shop from time to time. Long ago I built removable, and fairly airtight, floating inner door panels. These were built with drafts in mind, not sound. I clearly need to make a new set of panels that are much stiffer, and more carefully isolated from the outer doors.
Re: the attempted Darwin award... I actually did a quickie version of the test with the sub on the floor almost a week ago, and knew what I was getting into before ordering the drivers and then documenting the exact extent of my antisocial choice. Hey, I promised measurements!
Speaking of which, I'll do more tests with the real IB system later. Obviously won't be able to turn the reverse wave on and off, but I can compare the whole thing to my other subs. Also really curious to see if the building turns out to be really transparent to ULF.
About building the IB system even though I know it will be a potential annoyance:
After thinking about it a lot more, I decided I was... overthinking it.
I've heard IB systems elsewhere, and I really want to have that infra-bass experience on tap. If I have to restrict demo-level listening of the big system to reasonable hours, so be it.
On the occasions that I feel the need to listen to loud music late at night, I can probably manage to summon the energy it takes to walk the whole 8 feet required so I can plop down in the "Maxwell Guy" listening chair behind my mix position, and listen to my mid-field monitors instead.
That is normally what the sealed NHT subs are attached to, and in that spot, from that chair, they have plenty of output.
That said, I wasn't entirely kidding about the active noise cancellation idea. The Symetrix Radius I use for the main system's crossover has Dante, and I have both the DSP horsepower and enough Dante-enabled output channels (and amps) available to let me hook some Aurasound tactile transducers into the system. The thought was to bolt several of them to the inside of those barn-doors, feed them an appropriately filtered signal, and turn the doors into great big anti-woofers.
It would be a funny and relatively inexpensive stunt to attempt, and might even work. I promise that if I ever get around to trying it, I'll let you guys know.
More pressingly, I have to ask everyone for help on where to position the new IB system. New thread, I've already bloated this one enough.
Last edited:
Ok, I seem to have just typed "Maxwell Guy" in the previous post. Ouch! Apparently my subconscious self thinks I need to start a new career selling knockoff blank cassettes.
Pssst... wanna buy some 90 Minute Metal "KDK" tapes? I've got some too... even better than the "Maxwells"! Really Cheap. Just fell off the truck!
Re the tactile transducers... yes, if I buy some and they don't work out in their proposed role as barn door motion nullifiers, I could always put them to more traditional use, like attaching them to the listening room seats. I assume I could drop the sub levels down a bit. Seems like cheating, though ;0)
I do admit that I've always wanted to make a thump-enabled chair to augment headphone listening. I've had some variation of the Stax Lambda Pro on hand since the 80's. I think my current copy, and its amp, claims to be able to reproduce pretty low frequencies. True or not, without some body parts buzzing, it just doesn't feel like bass. A buzzy chair might fix that.
Such a system would be quite neighbor-friendly, but feel even *more* like cheating. Where's the challenge ;-)
Pssst... wanna buy some 90 Minute Metal "KDK" tapes? I've got some too... even better than the "Maxwells"! Really Cheap. Just fell off the truck!
Re the tactile transducers... yes, if I buy some and they don't work out in their proposed role as barn door motion nullifiers, I could always put them to more traditional use, like attaching them to the listening room seats. I assume I could drop the sub levels down a bit. Seems like cheating, though ;0)
I do admit that I've always wanted to make a thump-enabled chair to augment headphone listening. I've had some variation of the Stax Lambda Pro on hand since the 80's. I think my current copy, and its amp, claims to be able to reproduce pretty low frequencies. True or not, without some body parts buzzing, it just doesn't feel like bass. A buzzy chair might fix that.
Such a system would be quite neighbor-friendly, but feel even *more* like cheating. Where's the challenge ;-)
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