Matt, theres more to folding then anyone will try to argue...
You can ask David McBean.
Imagine The stretch of 240 (35.8hz) cm folded twice will create 3 x 80 cm. That removes the null formerly ASSumed to exist. Also as a well known and used TL as an offset @ 1/3. creating the same silution.
Matt, Whats ROAR got a lot of? Folds sir. Theres a bunch of folds. the math of that is missing, so please fact check me and then maybe consider a horn/ pipe might not be so bad or good? Its so interesting its worth it , i promise!
Whats 60 degrees? Or 45? Better than 90 or 180 in summed phase vectors? thats all found at the vent for each of these... wheres the vent at in the response? Wheres the middle of a tapped pipe at in the response? Wheres a paraflex HF chamber at zero degrees fir 71 hz? (Location)
Its really fun if you look. And its unfortunate if not... impulse response in these cabs in sim isnt a grain of salt IMO. it all crashes in the math
You can ask David McBean.
Imagine The stretch of 240 (35.8hz) cm folded twice will create 3 x 80 cm. That removes the null formerly ASSumed to exist. Also as a well known and used TL as an offset @ 1/3. creating the same silution.
Matt, Whats ROAR got a lot of? Folds sir. Theres a bunch of folds. the math of that is missing, so please fact check me and then maybe consider a horn/ pipe might not be so bad or good? Its so interesting its worth it , i promise!
Whats 60 degrees? Or 45? Better than 90 or 180 in summed phase vectors? thats all found at the vent for each of these... wheres the vent at in the response? Wheres the middle of a tapped pipe at in the response? Wheres a paraflex HF chamber at zero degrees fir 71 hz? (Location)
Its really fun if you look. And its unfortunate if not... impulse response in these cabs in sim isnt a grain of salt IMO. it all crashes in the math
Since ported and sealed boxes are both minimum-phase systems, they can be EQ'd to have identical frequency and impulse responses.
Seriously.
You can try it in Hornresp - take the curve of a ported box, and EQ a sealed box to match the frequency response. Then, check out the group delay curves.
Identical time domain performance.
Now, when we move from simulations to practical stuff, we must immediately implement a highpass filter for the ported box, to make sure a mic drop (ugh!) doesn't turn our subwoofers inside-out. The typical 4th order highpass will add a whole load of group delay which wasn't there before.
... And then there's all the processing happening in the mixing desk.
Chris
Yup.
And make sure that you are also comparing designs with the same or similar low frequency cutoff points. Your comparison seems to be between a 30 Hz BR and a 40 Hz ROAR, so impulse response will be different out the door.
To summarize, when you compare the two designs of same bandwidth within the bandwidth that are they designed to be used in, the impulse response curves should end up being a lot closer.
Subwoofers are basically bandwidth-limited devices, and usually very much so. Impulse response is probably not one of the differentiating factors between them, assuming of course that the design of the subwoofer does not introduce ridiculous levels of GD within its design passband.
Pls show me that Chris,
I can get them close but not the same.
Well, close in terms of group delay, but group delay is a relatively coarse, hard to follow representation of the finer differences shown with phase and impulse imo..
I'd also say a BR is very close to a minimum phase device, but not exactly one, as it makes sound from two or more spatial locations combined. If it weren't for the size of the wavelengths, it wouldn't be as close as it is to being true min phase, imo.
And i think you can make a lower order sealed mimic a higher order BR, but you can't mimic a sealed with a BR....iow, you can't reduce a BR's higher order without FIR, etc.
I can get them close but not the same.
Well, close in terms of group delay, but group delay is a relatively coarse, hard to follow representation of the finer differences shown with phase and impulse imo..
I'd also say a BR is very close to a minimum phase device, but not exactly one, as it makes sound from two or more spatial locations combined. If it weren't for the size of the wavelengths, it wouldn't be as close as it is to being true min phase, imo.
And i think you can make a lower order sealed mimic a higher order BR, but you can't mimic a sealed with a BR....iow, you can't reduce a BR's higher order without FIR, etc.
Good point on low feq cutoff..i was missing that.
And yep, all you say makes great sense.
I do try to avoid group delay as much as possible...as in the end, flat group delay= flat mag and phase = perfect impulse, yada yada, even for a low freq bandwidth-limited device.
Just won't be a very tall impulse for a sub,..but it can still be a clean impulse, huh? 🙂
Intresting, yet I still find myself asking the same uncomfortable question, have you heard these differences in real life? Serious question, have compared and evaluated it using your ears?
We are very good at looking into the details of simulations and measurements, but in the end the only thing that matters is how we actually perceive the sound, are there perhaps more important factors to consider in this outside of the usual suspects?
We are very good at looking into the details of simulations and measurements, but in the end the only thing that matters is how we actually perceive the sound, are there perhaps more important factors to consider in this outside of the usual suspects?
Binaural summing of small frequency gaps in each ear will sum to a certain extent by the brain and go undetected. Various hunan ears and brains skew this but fact remains we all
Have a baseline thanks to evolution. Our existence depended on this vestigual trait as a species.
If they are overlapped as harmonic intervals and farther spread, this is HUGEly increased. if a folded qw pipe Uses this advantage what happens?
Whats left over is sometimes used in medicine. I dont know that its all a bunch of
Null $h!t? Or bull sh!t, But the fact remains.
Pretty happy with what my ‘roar’ does that my paralex almost did. But i seem to be able to get the paraflex kind of close too by redesigning it. guess i realized i just needed to learn harmonics instead of try to copy ideas and slightly miss the potential.
i can now improve my roar. And not even name it. Its an ‘ everything’. But it wont sim. So i cant just guess, or explain. I look for the answers out side of the people who might not wantbtgeirs to be best. the info is missing. Do people even Care or is it all about $...
You guys are all lost. i think its time to realize you're looking for an advantage the wrong way.
Size or dollars as profit. youre all wrong! This is why paraflex is ‘sortof’ growing. But its slowly crippled by the same issues. If they jump
The hurdle of size and then scale back 1/4, they will
Becone moe and more relevant and simpler to build/design.
Will pataflex take over? No, i doubt it for sure. But is it closer to doing so if anything might....
Yes.
I can make a smaller pataflex. But in order to reallly use the idea i get pretty big again as a roar shape with two folds on each side of the drivers tapped entry.
200cm2, 400cm2, 800cm2, 1600cm2 in a vas and qts/fs that allows it. At 120/120 tap 80/80? Or jyst use air mass to divude what ine sating however tou like a wave propagation/Filtered by folding to be supported in a box
Have a baseline thanks to evolution. Our existence depended on this vestigual trait as a species.
If they are overlapped as harmonic intervals and farther spread, this is HUGEly increased. if a folded qw pipe Uses this advantage what happens?
Whats left over is sometimes used in medicine. I dont know that its all a bunch of
Null $h!t? Or bull sh!t, But the fact remains.
Pretty happy with what my ‘roar’ does that my paralex almost did. But i seem to be able to get the paraflex kind of close too by redesigning it. guess i realized i just needed to learn harmonics instead of try to copy ideas and slightly miss the potential.
i can now improve my roar. And not even name it. Its an ‘ everything’. But it wont sim. So i cant just guess, or explain. I look for the answers out side of the people who might not wantbtgeirs to be best. the info is missing. Do people even Care or is it all about $...
You guys are all lost. i think its time to realize you're looking for an advantage the wrong way.
Size or dollars as profit. youre all wrong! This is why paraflex is ‘sortof’ growing. But its slowly crippled by the same issues. If they jump
The hurdle of size and then scale back 1/4, they will
Becone moe and more relevant and simpler to build/design.
Will pataflex take over? No, i doubt it for sure. But is it closer to doing so if anything might....
Yes.
I can make a smaller pataflex. But in order to reallly use the idea i get pretty big again as a roar shape with two folds on each side of the drivers tapped entry.
200cm2, 400cm2, 800cm2, 1600cm2 in a vas and qts/fs that allows it. At 120/120 tap 80/80? Or jyst use air mass to divude what ine sating however tou like a wave propagation/Filtered by folding to be supported in a box
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Binaural summing of small frequency gaps in each ear will sum to a certain extent by the brain and go undetected. Various hunan ears and brains skew this but fact remains we all
Have a baseline thanks to evolution.
.If they are overlapped as harmonic intervals and farther spread, this is HUGEly increased. if a folded qw pipe y
Uses this advantage what happens?
Have a baseline thanks to evolution.
.If they are overlapped as harmonic intervals and farther spread, this is HUGEly increased. if a folded qw pipe y
Uses this advantage what happens?
Here lies your error. In order to match the 24dB/oct roll-off of a ported box using a sealed box with its natural 12dB/oct roll-off you have to introduce a 12dB/oct HP filter which will add group delay/phase shift (in similar fashion the port does in the first place) and match the ported boxes transfer function.
The problem is going the other way around. Take a 12dB/oct roll-off of a sealed box with its 180 degree phase shift at DC and match it by only using a parametric filter on a ported box that goes lower than the sealed box to begin with. You will still see 360 degree phase rotation at DC for the equalized ported box despite the frequency response matching the sealed box.
A sealed box alone is a minimum phase system.
A box/port and the driver are behaving much like a second order crossover system, and that is not a minimum phase system since there can be more than one combination of them that results in the same frequency response.
The port is in phase with the driver's front wave above its tuning frequency (and opposite phase of the rear wave that excites it due to port's natural 12dB/oct Low Pass acoustical behavior), constructively adding to the combined frequency response, but it drops to 180 degrees out of phase with the driver below the ports tuning frequency (acting much like the woofer's rear wave), resulting in cancellation and combined roll off that is about twice as fast as the sealed box system alone.
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Apart from having to change the statement concerning the minum phase characteristics for BR and add "above its tuning frequency" is this an issue in real life? Dont get me wrong, I'm grateful for your contribution, please keep it up, but seeing as BR designs are never to be used below their tuning frequency (at the risk of damaging drivers) this would be more of an academical issue, or am I missing something? (serious question, are there additional issues stemming from this above tuning?)
The issue can be described as academic because in real life you barely ever mix BR and sealed subs in one system. You either have one or the other.
But if you ever needed to tune and time align two types of subs in one system the phase behavior will have real world consequences. That's not to say that a clever engineer could not creatively use the differences to their advantage. It's just something that's there and needs to be taken in account.
In concert systems you high-pass subs anyway, at minimum you would just high pass sealed subs harder by 12dB/oct to match the BR subs.
But if you ever needed to tune and time align two types of subs in one system the phase behavior will have real world consequences. That's not to say that a clever engineer could not creatively use the differences to their advantage. It's just something that's there and needs to be taken in account.
In concert systems you high-pass subs anyway, at minimum you would just high pass sealed subs harder by 12dB/oct to match the BR subs.
Hello!
Nice discussion, I have read it all. It is very similar to some other discussions around. maybe some users will know what I mean...
There are merits to everything, but I believe we don´t get anywhere (especially agree to disagree) if we don´t use particular comparison. Must be more "concrete".
Regarding GD and "impulse/transient response":
That advantage is greatly hindered once you use HPF and LPF and even real environment. So while it is there, I would not stand on it like end-all be all gamechanger for particular design.
I was interested in ROAR12, but compared to modern high end ported box, if power density and range is important, it doesn´t look that tempting anymore.
I have simmed RCF LF21N551 in 135l (net) volume, it will outdo ROAR12 with 12TBX100 by about 15Hz. Okay, maybe less, if I cheat a little with HPFing sooner for getting rid of BR compression issues. But on the other hand, LF21N551 will totally go 2dB higher with cone excursion, because it does not compress till about 20,5mm much, while B&C is tighter. So the tip of the peak at 33Hz actually can be taken as baseline for rest of the band up, and even if it isn´t it is still fair 10Hz advantage, and that´s not "nothing".
It will cost more, it will eat more power, so it is inefficient, but electricity is not a large sum of money in that equation, so not many will care.
ROAR12 shows 230,4l box volume, the BR bin I am trafficking is 239,1l.
That way in my eyes, ROAR 12 size wise is outdone by stoopid ported bin. Easy to make, power dense, great extension down.
The SPLMax figure compared in Hornresp:
In the image, there is B&C 21D115 in the bin, and it "barely didn´t make it" with full power for acceptable/marketable product that would wow people:
With RCF LF21N551, it does.
Nice discussion, I have read it all. It is very similar to some other discussions around. maybe some users will know what I mean...
There are merits to everything, but I believe we don´t get anywhere (especially agree to disagree) if we don´t use particular comparison. Must be more "concrete".
Regarding GD and "impulse/transient response":
That advantage is greatly hindered once you use HPF and LPF and even real environment. So while it is there, I would not stand on it like end-all be all gamechanger for particular design.
I was interested in ROAR12, but compared to modern high end ported box, if power density and range is important, it doesn´t look that tempting anymore.
I have simmed RCF LF21N551 in 135l (net) volume, it will outdo ROAR12 with 12TBX100 by about 15Hz. Okay, maybe less, if I cheat a little with HPFing sooner for getting rid of BR compression issues. But on the other hand, LF21N551 will totally go 2dB higher with cone excursion, because it does not compress till about 20,5mm much, while B&C is tighter. So the tip of the peak at 33Hz actually can be taken as baseline for rest of the band up, and even if it isn´t it is still fair 10Hz advantage, and that´s not "nothing".
It will cost more, it will eat more power, so it is inefficient, but electricity is not a large sum of money in that equation, so not many will care.
ROAR12 shows 230,4l box volume, the BR bin I am trafficking is 239,1l.
That way in my eyes, ROAR 12 size wise is outdone by stoopid ported bin. Easy to make, power dense, great extension down.
The SPLMax figure compared in Hornresp:
In the image, there is B&C 21D115 in the bin, and it "barely didn´t make it" with full power for acceptable/marketable product that would wow people:
With RCF LF21N551, it does.
Intresting Crashpc, that is if a strict volumetrical comparrison where the criteria, don't get me wrong, it is interesting to see for sure, thank you, but what if we level the transducer cost and size a bit and let loose the size a bit, something just feels wrong about comparing a 12" to a 21", even if they both get the same volume.
Another interesting comparison would be to put a really good 218, say l'acoustics ks28, towards the ROAR18, using the same 18SW115 drivers, the ROAR18 would be slightly larger (I assume) but on the other hand it would use half the the driver complement.
Another interesting comparison would be to put a really good 218, say l'acoustics ks28, towards the ROAR18, using the same 18SW115 drivers, the ROAR18 would be slightly larger (I assume) but on the other hand it would use half the the driver complement.
I really want to add to this discussion. But i really want yo note that for a very long time circlomenen had to waste half of his efforts in proving things to the onslaught of opposing guesses to his guesses. It quickly becomes annoying to anyone who is already interested in the roar for no other reason then its use of
A pipe inside a pipe.
Long story short. the roar caught on iregardless. Infact its smeared into a lot if things and itself is a collection of whatever its brainstorm resulted from in the two men who were its fathers.
As it turns out so much of what Circlo’ was saying is and always is true.
The technical terms or the references used to attempt to share a sensation were prsonal choices to ones own persp
Eorion to frequency and transient and overlapping things that nobody can describe in a moment or a period in no certain frequency. However a curious person can help create any sound or bunches of them. boundary condition and very quickly chase things and research similar areas of sound in ducts, exhausts and parallel and series, offset dead ends and damped or undamped regions with any variety of conditions and realize that man (if he reads this 🙂 )was not only a genius with a very creative side. But that the annoying contrary atitude he was always forced to politely address was only half correct in their quest for policing the things about that or any design measured or not.
its not exclusive to roar, or ay roar in particukar. Its exactly as is said by anyone using the same driver and in the sane design and its complexity as prescribed.
roar needs to be put back onto the exam table. Because all it needs is more drivers and more people using whatever driver into it they might and however the shape the roar they might choose as well. I think its clear how or what direction that might be useful. its simple. its universal.
But also theres more going on here thats a qw pipe and another pipe with folds in ut tgat all share or dont. A interval of length and a shared one tgat equat to the real one in a reference point to the full wave being used to do so. who defines how pipe physics actually work? Nobody. Cross refeence ot into thermo acoustics engines and closed end pipes and music, harmony, and AC current, antenaes, and aeronautica atuff...thdn come back and guess what to use and measure and sim for that frequency and response being used to stake a claim to whag it is..??
Whatever you cone up with, if its real its universal.
the slow migration of the entire use of and furthering upon past things as stepping stones is in many places coming full circle(no pun intended (.
if you loook or if you care to, its there to see. it might look familiar, or only parts of it. But whatever you see. If its being studied or popular its not because
Its far from optimal.
i dont kniw what the question is. But i dont care either. All i know is it might be time to look at roar and or tham. ?
As the future of fun. not any otger way.
A pipe inside a pipe.
Long story short. the roar caught on iregardless. Infact its smeared into a lot if things and itself is a collection of whatever its brainstorm resulted from in the two men who were its fathers.
As it turns out so much of what Circlo’ was saying is and always is true.
The technical terms or the references used to attempt to share a sensation were prsonal choices to ones own persp
Eorion to frequency and transient and overlapping things that nobody can describe in a moment or a period in no certain frequency. However a curious person can help create any sound or bunches of them. boundary condition and very quickly chase things and research similar areas of sound in ducts, exhausts and parallel and series, offset dead ends and damped or undamped regions with any variety of conditions and realize that man (if he reads this 🙂 )was not only a genius with a very creative side. But that the annoying contrary atitude he was always forced to politely address was only half correct in their quest for policing the things about that or any design measured or not.
its not exclusive to roar, or ay roar in particukar. Its exactly as is said by anyone using the same driver and in the sane design and its complexity as prescribed.
roar needs to be put back onto the exam table. Because all it needs is more drivers and more people using whatever driver into it they might and however the shape the roar they might choose as well. I think its clear how or what direction that might be useful. its simple. its universal.
But also theres more going on here thats a qw pipe and another pipe with folds in ut tgat all share or dont. A interval of length and a shared one tgat equat to the real one in a reference point to the full wave being used to do so. who defines how pipe physics actually work? Nobody. Cross refeence ot into thermo acoustics engines and closed end pipes and music, harmony, and AC current, antenaes, and aeronautica atuff...thdn come back and guess what to use and measure and sim for that frequency and response being used to stake a claim to whag it is..??
Whatever you cone up with, if its real its universal.
the slow migration of the entire use of and furthering upon past things as stepping stones is in many places coming full circle(no pun intended (.
if you loook or if you care to, its there to see. it might look familiar, or only parts of it. But whatever you see. If its being studied or popular its not because
Its far from optimal.
i dont kniw what the question is. But i dont care either. All i know is it might be time to look at roar and or tham. ?
As the future of fun. not any otger way.
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Ouch, Those images I have posted, do not enlarge. I don´t know anymore where to upload these....
martisson:
Well, we can try at least sim that. Cheaper 18" will definitely need to be tuned higher, as it will not keep up with cone excursion/volume displacement. I am not sure how long it will keep up by interchanging range (down) and SPL between each other. We can try, it would be fun.
It all boils down to needs, approach and such. No bin is the best one. My input was related to the main topic - reason for people staying with ported bins, size issues, power density issues. The BR keeps up in certain classes, and that´s about it.
It is my opinion, it is only for my use case, and so on. Maybe some people feel it the same, and others don´t that´s fine. My job is done by showing very usable use case, which is competing in selected aspects well.
What I have heard about ROAR lures me to build one or two for sure. Just to gain more experience. Same as with other HOQW designs (MOAR and others).
Booger weldz: I got you. My input was not related directly towards ROAR, but towards main topic reasoning and why BR is still used - it still can have advantages. And that´s about it. Indeed, if you do engineering and DIY, later on you find it is "all same all same", with just some additional features here and there, solving issues on different orders of magnitude, but still, all same...
martisson:
Well, we can try at least sim that. Cheaper 18" will definitely need to be tuned higher, as it will not keep up with cone excursion/volume displacement. I am not sure how long it will keep up by interchanging range (down) and SPL between each other. We can try, it would be fun.
It all boils down to needs, approach and such. No bin is the best one. My input was related to the main topic - reason for people staying with ported bins, size issues, power density issues. The BR keeps up in certain classes, and that´s about it.
It is my opinion, it is only for my use case, and so on. Maybe some people feel it the same, and others don´t that´s fine. My job is done by showing very usable use case, which is competing in selected aspects well.
What I have heard about ROAR lures me to build one or two for sure. Just to gain more experience. Same as with other HOQW designs (MOAR and others).
Booger weldz: I got you. My input was not related directly towards ROAR, but towards main topic reasoning and why BR is still used - it still can have advantages. And that´s about it. Indeed, if you do engineering and DIY, later on you find it is "all same all same", with just some additional features here and there, solving issues on different orders of magnitude, but still, all same...
Independent of anything look at what you can see if overlapping sim as parts and reference to a full wave they are crossed to. attached to, sum as part of etc..
And realize that as a pipe. Pipe physics.
Now use hirn response math for TS parameters specific to a Nd for vas and qts for Fs. play around til you found a small proper qw pipe. everything after, not before it is now based on it. That might neeed to be folded in half. It needs whatever makes those two pipes hit on the same spots or a half? whays the middle or half between those pipes is only slightly different then a kink at the end f the first pipe? a assumption where thd pupe is and ends or starts im pressure phase to the other??
shake it up as pieces and then look again. I think its so close its incredble. i think its time to look. Cause if you're not other people are using the table scraps regardkess if yiu finished dinner 🙂
And realize that as a pipe. Pipe physics.
Now use hirn response math for TS parameters specific to a Nd for vas and qts for Fs. play around til you found a small proper qw pipe. everything after, not before it is now based on it. That might neeed to be folded in half. It needs whatever makes those two pipes hit on the same spots or a half? whays the middle or half between those pipes is only slightly different then a kink at the end f the first pipe? a assumption where thd pupe is and ends or starts im pressure phase to the other??
shake it up as pieces and then look again. I think its so close its incredble. i think its time to look. Cause if you're not other people are using the table scraps regardkess if yiu finished dinner 🙂
No, i was agrreeing with you if you missed that. I hare typing its too hard to even try ..just assume tge best at all times 🙂
But no matter whaat if roar had 1/4, 1/8? 1/3?of its huge second pipe made into an absorber and that was raper of to theend of the pipe it would be centered in and with two opposed drivers in separate qw pipes that all join at that second pipe. You fave a tapered absorber. And a flair On the last pipe or as steps you keep things in check. And look at the phase for the fullwave of the original.. out to13/4 s.. unwrapped
Split roars upper pipe as if its folding at the split of the pressure null and the Pipe must be a certain way in regards to the longer one.. in fact thee isn't a longer one, theres seperate pipes with an in phase driver tap? And do the shuffle as a circle rotating around a circle. The timing mark repeats and of it does in a certain shape?? spin it out to observe the result. hows that looking? Make it better its not hard. It might be hard to fold cause its probably ifferent?
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Bhaha, my mistake, English is not my native language, but still. Daaam, this is hard to read. Did you know that one indication of covid is person´s confusion (acting)? 🙂
But no matter whaat if roar had 2/3 of its huge second pipe made into an absorber and that was raper of to theend of the pipe it would be centered in and with two opposed drivers in separate qw pipes that all join at that second pipe. You fave a tapered absorber. And a flair On the last pipe or as steps you keep things in check. And look at the phase for the fullwave of the original.. out to13/4 s.. unwrapped