Didgeridoo joke is more real here then joke, btw. Look it up and consider the parts of the human / pipe as lungs/diapram, throat / mouth / instrument? We still breath through our noses while playing, by sqeezing our cheeks on air volume stored in mouth, but the rhythm and frequency is lower for that time, and then returns once the gasp of air is take in and normal play resumes.
So here is the latest incarnation, with two folds, three pipes, and it now has much more bottom end. You'd never know there was a 10-inch driver in the middle of all that pipey goodness.
It's into the 20s in room in all likelihood, getting about as low as the big TL box, which is tuned to 25Hz.
At present the rings in the outer stack are just sitting one atop another. I shall glue them together today which should rid it of any air leaks. And create some sort of more aesthetic top cap! Not that it will win any beauty prizes even then.
First photo a bit blurry, second better.
It's into the 20s in room in all likelihood, getting about as low as the big TL box, which is tuned to 25Hz.
At present the rings in the outer stack are just sitting one atop another. I shall glue them together today which should rid it of any air leaks. And create some sort of more aesthetic top cap! Not that it will win any beauty prizes even then.
First photo a bit blurry, second better.
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I had another idea too -probably silly but there you go - which I should try given how easy it is to implement. At present, the RSS265HO-44 is right at the beginning of the line, attached to the top of the innermost pipe.
It would be no big deal at all to reverse its position and slot it at the bottom of the first pipe, upward facing, and resting on a few bits of thick foam so as its vent isn't blocked.
That way it is one-third of the way down the line, as it were, approximately. No harm in trying.
Having heard what this can do vis a vis my 15-inch monster TL, there are clearly other ways to skin the cat. I've also found that lining the inner pipe with sound absorbing material seems to remove an element of echo, so I guess is nixing some of the unwanted resonances/harmonics.
I've always liked the sound of cylinders; their inherent rigidity gives them an advantage over boxes IMO.
That said, Im seriously tempted now to build a tapped sub using the 15-inch Dayton, something tall and simple to construct (in a coffin, yes) about 17x20 inches, and up to 1.3m in height. Which would be internal volume 285L or so. Probably with just a single fold. A bit taller I might get away with, if it's skinny enough.
Meantime, Im going to enjoy the new Pied Piper. It's genuinely great as is. Again thanks for your guidance guys.
Will rip the scab off the top and insert the black end cap.
It would be no big deal at all to reverse its position and slot it at the bottom of the first pipe, upward facing, and resting on a few bits of thick foam so as its vent isn't blocked.
That way it is one-third of the way down the line, as it were, approximately. No harm in trying.
Having heard what this can do vis a vis my 15-inch monster TL, there are clearly other ways to skin the cat. I've also found that lining the inner pipe with sound absorbing material seems to remove an element of echo, so I guess is nixing some of the unwanted resonances/harmonics.
I've always liked the sound of cylinders; their inherent rigidity gives them an advantage over boxes IMO.
That said, Im seriously tempted now to build a tapped sub using the 15-inch Dayton, something tall and simple to construct (in a coffin, yes) about 17x20 inches, and up to 1.3m in height. Which would be internal volume 285L or so. Probably with just a single fold. A bit taller I might get away with, if it's skinny enough.
Meantime, Im going to enjoy the new Pied Piper. It's genuinely great as is. Again thanks for your guidance guys.
Will rip the scab off the top and insert the black end cap.
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A 3rd of the total pipe length offset in theory and HR, puts it in a deep null.
Correct, any type TL not made in concrete or similar needs some damping and even then, round pipes require some due to also having a theoretical infinite number of [summed] eigenmodes of the same frequency across its diameter.
You're welcome!
GM
Hmm, scotch that idea then!
But yes, the damping has helped.
Thanks GM.
BW: I chose the 250 pipe because the driver fits in the end so perfectly. I can always try putting a bit of clobber in the smallest pipe, like other small pipes, to narrow it down some. See how that goes?
But yes, the damping has helped.
Thanks GM.
BW: I chose the 250 pipe because the driver fits in the end so perfectly. I can always try putting a bit of clobber in the smallest pipe, like other small pipes, to narrow it down some. See how that goes?
Basic TH ~ follows BR alignment design WRT to driver selection, Fb[p], so for your pipe length, need an Fs for an end loaded TL, ~0.4 Qt for flattest response. Note that horn theory dictates designing based on an acoustic 1/2 octave [0.707x] below Fs.
B0$3 proved that a 2:1 CR was optimal for constant taper and prosound has proven a 3:1 max for [horn] tapered, though in each case it's for drivers best suited for vented, which your current driver isn't, so will always have the 'saddle' unless tuned below Fs based on vented box theory, which in turn lowers power handling with progressively lower tunings.
No such thing as too many subs, just a point of diminishing returns: [PDF] Low-Frequency Optimization Using Multiple Subwoofers | Semantic Scholar
GM
Had a 'senior moment' within a 'senior moment'; forgot about the pipe's end corrections being somewhat summed in PiP, so guesstimated it based on HR's/your's Fp, making the effective length for the meter pipes ~141.97 cm long, but even then it only gets it down to ~35 Hz from ~50 Hz and the increased length required to get to 31 Hz is ~172.97 cm, which at ~73% longer than the pipes still isn't making sense even with the elbow added, so without an accurate dimensioned drawing to maybe resolve this plus this new pipe to factor in, 'color' me done [for now].
Good luck with it.
GM
attached: ~31 Hz TH PiP
The pipe is 490cm2?
Odds are more likeky im wrong, but i kept tripping up on the pipe fitting the driver myself, with no coupler, etc? 248cm2 at 350cm as a generic simple qw pipe for the Fs@qts and Vas (as CSA and length). it can be a tapped pipe or an offset driver with minor tweaking from there. i cant really help, i dunno any pipe or national pipe sizes overseas?
Odds are more likeky im wrong, but i kept tripping up on the pipe fitting the driver myself, with no coupler, etc? 248cm2 at 350cm as a generic simple qw pipe for the Fs@qts and Vas (as CSA and length). it can be a tapped pipe or an offset driver with minor tweaking from there. i cant really help, i dunno any pipe or national pipe sizes overseas?
So just to be clear the inner pipe to which the driver is attached at the top end is 233mm internal/250mm external diameter. No coupler; it literally screws into the top of the 1m long pipe (39.5 inches).
The outer pipe is 300mm outer diameter, 284mm inner, and 97cm tall.
And finally the third pipe which goes over the top of those two (nesting the others then) is 400mm external diameter, 380mm internal and is 1165mm tall.
See pics below to get a better idea.
And GM the elbow is gone; the 400mm pipe 116.5cm replaces that!
The outer pipe is 300mm outer diameter, 284mm inner, and 97cm tall.
And finally the third pipe which goes over the top of those two (nesting the others then) is 400mm external diameter, 380mm internal and is 1165mm tall.
See pics below to get a better idea.
And GM the elbow is gone; the 400mm pipe 116.5cm replaces that!
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Dunno; after seeing your Q made me wonder since I was using a circa '94 memory of my then workplace's pipe comparison chart and as it turned out my [lack of] memory gave me a trifecta of 'senior moments' [Sn^3 ?], so even the latest, now obsolete, sim isn't correct, but correcting volumes and their minor end correction differences won't solve my 'dilemma'. 🙁
Googled this: Difference | Imperial & Metric PVC | epco Pipe Systems
GM
......at this point, you can use one of my incorrect HR BP6 sim
GM
Pi • r^2
With the pipe stuck in a pipe as you stated, the 80cm2 left available outside the first pipe path is less than ideal, if not a impossible to be useful. Even as a bass reflex it would be a bit small in CSA ?
Stop using diameters to describe a cross section.... length(start to end of pipe) is equally vital but it is the Length for qw tuning Fb. Nobody us gonna want/need ‘diameter’. Cm2 is used at a cm length, as a pipe shape, to tune the sound wave. Diameter is useful in turns/ folding, but is only further confusing me😀 ‘Sd, S1-S5, Atc, Ap....’ all in cm2 in a qw simulator of AREA. at a stated length (not diameter) which together create a measure if Volume. or changes in it as traveling through the pipe toward exit or into chambers, etc.?
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Hmm, that makes me wonder then what size the pipe directly outside the inner pipe should ideally be, presuming I stick with the smallest pipe as it is (of course it could be made longer). That way I could optimise it as a two-pipe system instead of doing the nesting (as with three pipes).
Another alternative is to use a slightly bigger inner pipe and just mount the driver motor out on an end cap.
As it is, this sub is really sounding pretty good, but if the sims suggest it could be optimised with more appropriately sized pipe, then so be it, Im happy to do that.
Alternatively, given the Dayton isn't ideal for this set up, I could also look at getting another driver that is better suited to the purpose.
If it was a car sub, like an Alpine, so much the better, given they're not terribly expensive here but meant to be decent quality.
The final option is giving away the Pipe Dream and building a more conventional TH instead, providing it's a simple build. I cant doing anything that doesn't have right angles. Im sure I could manage to learn otherwise though, if pressed for good reason.
Another alternative is to use a slightly bigger inner pipe and just mount the driver motor out on an end cap.
As it is, this sub is really sounding pretty good, but if the sims suggest it could be optimised with more appropriately sized pipe, then so be it, Im happy to do that.
Alternatively, given the Dayton isn't ideal for this set up, I could also look at getting another driver that is better suited to the purpose.
If it was a car sub, like an Alpine, so much the better, given they're not terribly expensive here but meant to be decent quality.
The final option is giving away the Pipe Dream and building a more conventional TH instead, providing it's a simple build. I cant doing anything that doesn't have right angles. Im sure I could manage to learn otherwise though, if pressed for good reason.
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Again, [Sd]/3 is considered the woofer horn's max CR, though at partial power, 4:1 is probably OK.
For reflex, it's a complex calculation, so need to figure its vent mach and if using it to figure these pipes [and some claim really should], then to get the desired 1/4 WL the pipe area can be somewhat >[Sd], so back when I was doing it pre-T/S till MJK did his MathCad worksheets I designed a BR, then converted its [Vb] to 'x' vent pipe diameter and added the vent's to it, i.e. morphed the sums of the box, vent volumes into a 1/4 WL pipe alignment.
GM
This forum is chockablock with information.
Somewhere on the subwoofer area I read recently that placing a subwoofer near the listening position is a good place to begin experimenting with optimal sub room placement.
So I stuck the pipe-in-a-pipe sub in the corner by the sofa and it didn't sound that good, too boomy. Then I moved the sofa forward a bit and lay it down in behind, up against the rear wall. Kind of like the situation with this subwoofer
The Hideaway TL Sub | audioXpress
So with the crossover set below 80Hz, all you hear /see is this tiny pair of Karlsonator speakers with 4.5 inch full range driver doing bass down into the 30s. It's kind of freaky and weird cool at the same time.
And that gets me thinking that it must be possible to do a tapped horn design like this, with height minimised, width and length maxed out, and the driver up/down facing in the single-fold divider. Guess I'd better check about under-sofa clearance first! If that doesn't work the hideaway sub just might.
And I have a left-over box that takes both my RSS265HO-44s, so this might well be a project that requires a modicum of work. The tricky bit would be the sims.
Somewhere on the subwoofer area I read recently that placing a subwoofer near the listening position is a good place to begin experimenting with optimal sub room placement.
So I stuck the pipe-in-a-pipe sub in the corner by the sofa and it didn't sound that good, too boomy. Then I moved the sofa forward a bit and lay it down in behind, up against the rear wall. Kind of like the situation with this subwoofer
The Hideaway TL Sub | audioXpress
So with the crossover set below 80Hz, all you hear /see is this tiny pair of Karlsonator speakers with 4.5 inch full range driver doing bass down into the 30s. It's kind of freaky and weird cool at the same time.
And that gets me thinking that it must be possible to do a tapped horn design like this, with height minimised, width and length maxed out, and the driver up/down facing in the single-fold divider. Guess I'd better check about under-sofa clearance first! If that doesn't work the hideaway sub just might.
And I have a left-over box that takes both my RSS265HO-44s, so this might well be a project that requires a modicum of work. The tricky bit would be the sims.
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Indeed! I started to 'expand' your 'world' re all the considerations of sub systems way back at the beginning of your 'journey', but concluded it was too far beyond the scope of your goal to be worth the effort and as you've found, researching it yields an incredible amount of existing knowledge/'prior art' in patent lingo 😉.
To add to it re sofa/listening position [Lp], speakers and Lp should normally be at an odd harmonic, so [mains] speakers against the [sound] wall [fundamental], then your ears ideally should be at 1/5, 1/3, etc.; once speakers are moved far enough away to be in an even harmonic, 1/4, 1/2. etc.; then more flexibility in Lp location, but now you've got to search for it, hence all the different ways [sales] folks instruct/suggest, though of course whole room measurements are best overall.
Optimal sub location is a bit more complex, so better to research it.
FIY/FWIW, DSL's THSpud/'couch potato' DTS concept TH: THSpud | Danley Sound Labs, Inc.
Search it to find all the DIYer's versions/variants and similar.
GM
edit: Worst position in a basic room is speaker at sound wall, LP at room midpoint in both planes [deepest/widest null].
To add to it re sofa/listening position [Lp], speakers and Lp should normally be at an odd harmonic, so [mains] speakers against the [sound] wall [fundamental], then your ears ideally should be at 1/5, 1/3, etc.; once speakers are moved far enough away to be in an even harmonic, 1/4, 1/2. etc.; then more flexibility in Lp location, but now you've got to search for it, hence all the different ways [sales] folks instruct/suggest, though of course whole room measurements are best overall.
Optimal sub location is a bit more complex, so better to research it.
FIY/FWIW, DSL's THSpud/'couch potato' DTS concept TH: THSpud | Danley Sound Labs, Inc.
Search it to find all the DIYer's versions/variants and similar.
GM
edit: Worst position in a basic room is speaker at sound wall, LP at room midpoint in both planes [deepest/widest null].
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Nice, but that's too big for my application and the build is a bit complex too. Sometimes there's something to be said for simplicity.
Besides, as it is, I get requests to "turn down the bass cos it's making me sick".
Er, the bass is already turned down, darl. If I turned it down any further it would be off.
Which would presumably be perfect.
So no, a simple, single fold enclosure is probably best in these circumstances.
Besides, as it is, I get requests to "turn down the bass cos it's making me sick".
Er, the bass is already turned down, darl. If I turned it down any further it would be off.
Which would presumably be perfect.
So no, a simple, single fold enclosure is probably best in these circumstances.
Understood, just posted to show a high end TH variant. Yes, a single fold [divider board] is normally sufficient for the vast majority of systems or folded more of course if it needs to be a 'coffee' or 'end' table.
The last ones I built ages ago were sofa back height, width as bookcases mostly for VHS, LDs, early DVDs.
Yeah, deep bass can vibrate their reproductive systems in unpleasant ways, but women in general really love a traditional prosound response, i.e. flat from 300 - 80 Hz/60 Hz F3/40 Hz F6 [AKA max flat 40 Hz BR], then EQ mid bass 'bump' to [her] 'taste' in your case.
GM
The last ones I built ages ago were sofa back height, width as bookcases mostly for VHS, LDs, early DVDs.
Yeah, deep bass can vibrate their reproductive systems in unpleasant ways, but women in general really love a traditional prosound response, i.e. flat from 300 - 80 Hz/60 Hz F3/40 Hz F6 [AKA max flat 40 Hz BR], then EQ mid bass 'bump' to [her] 'taste' in your case.
GM