A 316grm cone may simply not be as detailed and as high in SQ as a 106grm cone with 65% of the motor strength. Ported for ported and sealed for sealed, this is a heavy cone even taking into account its Bl of 22.
Its not an EQ curve. Its flat. EQ doesnt= SQ. Lighter cones react faster. I do agree that having ponderous bass due to one frequency dominating the sound can skew the sound but its not going to speed up or slow down how fast a cone reacts to an input signal.
Anyway, I wont be putting a towel in my ported box's vent. I'm using a real sealed box built just for this sub. Maybe I will love it.
When TC was produced in house they had a "full power" type excursion check as part of final QC, I've heard it over the phone and when things did not go well it made me cringe.
I would not expect a significant shift in parameters unless you push the driver to the limits of excursion and get abusive with them...
The TC Epic 12" is a whole different animal ported. The group delay peaks at 22ms at 15hz and at 25hz its 18ms in a 2 cube box.
The cone weighs nearly 1/2 of the LMSr 12 at 160 grms and the Bl is 15.
I'd expect that to sound exactly as you described.
UPDATE
As discussed, I reduced the net internal volume of the ported box from 2.05 to 1.85 by adding a 7" cube inside the box to take up about .2 cubes. The resulting decrease in box volume also raised the tuning frequency from 25 to 26.7hz. the idea here being to let the driver have more of a mechanical advantage over the internal box air load. I've read that extended bass shelf subs can have a slight degradation of SQ over smaller flat alignments often being accused of one note bass which I absolutely agree with when the driver has a high Qts.
Anyway, yes it did have a much better subjective presentation. The group delay measures better from 31ms down to 27ms....not sure if that is much of anything but its a step in the right direction.
I'm going to go down another .1 cubes to 1.75 which will raise the tuning to 27.5 or so with marginal decreases in group delay.
The sealed box just needs to dry so that will be my fun for tomorrow.
So yes it already sounds better. I think the tuning was too low anyway.
As discussed, I reduced the net internal volume of the ported box from 2.05 to 1.85 by adding a 7" cube inside the box to take up about .2 cubes. The resulting decrease in box volume also raised the tuning frequency from 25 to 26.7hz. the idea here being to let the driver have more of a mechanical advantage over the internal box air load. I've read that extended bass shelf subs can have a slight degradation of SQ over smaller flat alignments often being accused of one note bass which I absolutely agree with when the driver has a high Qts.
Anyway, yes it did have a much better subjective presentation. The group delay measures better from 31ms down to 27ms....not sure if that is much of anything but its a step in the right direction.
I'm going to go down another .1 cubes to 1.75 which will raise the tuning to 27.5 or so with marginal decreases in group delay.
The sealed box just needs to dry so that will be my fun for tomorrow.
So yes it already sounds better. I think the tuning was too low anyway.
Yes I read all posts, don't assume the answer you got from me was based on the first post, I'm just trying to convey from many installs in car and home what my general observations have been, regardless of numbers and science... to a certain degree.
Also don't assume that because a ported alignment with an entirely different driver worked in the past that it will guarantee another driver in a ported alignment to sound or react the same in your vehicle, it really doesn't work quite that way. Remember three variables, box, cabin and driver, if you account for all these your optimal alignment may just surprise you. Please don't think I'm giving you a lesson here, or saying your not doing things right, there is just more to look at here than just the driver and it's electrical/mechanical functions in a said alignment. And being in a truck I've found cabin gain is much more pronounced due to size.
I'm betting if you get the tuning to around 30Hz or so things will take a drastic change for the better. And I also have a feeling that output below 30Hz will still be more than adequate... This driver does have gobs of excursion available (cabin gain is a wondrous beast she is)... . If my feelings are indeed wrong I'll subject myself and the neighbors to 120dB's of the Nom Nom song... 
On a side note...I have found EBS alignments rather flat sounding, and not incredibly effective in presenting a solidly defined bottom end. Home Theater where musicality is not really a major issue is another story. I've built a few from 10-15" and every one had the same tendency to sound muddy below 60hz. The 15" was a TC LMS-R and although output was astonishing, musicality was not a strong point. Switching this driver into a much, much smaller .5qtc sealed alignment made a huge difference in musicality, but required EQ to achieve flat response in room to 20Hz. EBS alignments generally don't sound all that good in car from my personal experiences as the cabin generally creates a boomy sounding system again IMHO. I'm not saying your experiences have to be the same or will be, I'm just stating what I've personally deduced in the past.
Also don't assume that because a ported alignment with an entirely different driver worked in the past that it will guarantee another driver in a ported alignment to sound or react the same in your vehicle, it really doesn't work quite that way. Remember three variables, box, cabin and driver, if you account for all these your optimal alignment may just surprise you. Please don't think I'm giving you a lesson here, or saying your not doing things right, there is just more to look at here than just the driver and it's electrical/mechanical functions in a said alignment. And being in a truck I've found cabin gain is much more pronounced due to size.
I'm betting if you get the tuning to around 30Hz or so things will take a drastic change for the better. And I also have a feeling that output below 30Hz will still be more than adequate... This driver does have gobs of excursion available (cabin gain is a wondrous beast she is)...
. If my feelings are indeed wrong I'll subject myself and the neighbors to 120dB's of the Nom Nom song... On a side note...I have found EBS alignments rather flat sounding, and not incredibly effective in presenting a solidly defined bottom end. Home Theater where musicality is not really a major issue is another story. I've built a few from 10-15" and every one had the same tendency to sound muddy below 60hz. The 15" was a TC LMS-R and although output was astonishing, musicality was not a strong point. Switching this driver into a much, much smaller .5qtc sealed alignment made a huge difference in musicality, but required EQ to achieve flat response in room to 20Hz. EBS alignments generally don't sound all that good in car from my personal experiences as the cabin generally creates a boomy sounding system again IMHO. I'm not saying your experiences have to be the same or will be, I'm just stating what I've personally deduced in the past.
Also don't assume that because a ported alignment with an entirely different driver worked in the past that it will guarantee another driver in a ported alignment to sound or react the same in your vehicle, it really doesn't work quite that way.
EBS alignments generally don't sound all that good in car from my personal experiences as the cabin generally creates a boomy sounding system again IMHO. I'm not saying your experiences have to be the same or will be, I'm just stating what I've personally deduced in the past.
Agree on all your points here and thanks for the input.
Today I didnt finish cutting the hole for the driver in the sealed box but I did reduce the net internal volume to 1.7 cubes and tuned to 27 on my ported box. As I get away from the EBS alignment, I am getting the sound I want.
These reductions converge upon a 1.4 cube allignment at 27hz for the minimum group delay and I suspect the best detail and punch. I never would have thought that .35 cubes and a 25hz tuning would be so muddy sounding. Group delay falls from nearly 31ms to 24ms and the smaller internal volume seems to let the driver react faster. Yes slight changes make all the world of difference.
I will build a smaller 1.4 cube box and stay with the driver (keeping it) and tune it to 27 which is the best mix of group delay, lowest -3db point, and likely SQ in my truck. The sealed box will be tested so I have first hand experience with it. I tried most of my subs ported and sealed and never heard a sealed system I could live with. Even 7db at 25hz uses too much power to get there and just doesnt sound effortless at the volumes I listen at.
I'm really happy even at the 1.7 cube step but hey doesnt everyone try 7 alignments before they settle where they want to be? Seriously, I think most people who tout one box style over another never tried anything but what they have.
These reductions converge upon a 1.4 cube allignment at 27hz for the minimum group delay and I suspect the best detail and punch. I never would have thought that .35 cubes and a 25hz tuning would be so muddy sounding. Group delay falls from nearly 31ms to 24ms and the smaller internal volume seems to let the driver react faster. Yes slight changes make all the world of difference.
I will build a smaller 1.4 cube box and stay with the driver (keeping it) and tune it to 27 which is the best mix of group delay, lowest -3db point, and likely SQ in my truck. The sealed box will be tested so I have first hand experience with it. I tried most of my subs ported and sealed and never heard a sealed system I could live with. Even 7db at 25hz uses too much power to get there and just doesnt sound effortless at the volumes I listen at.
I'm really happy even at the 1.7 cube step but hey doesnt everyone try 7 alignments before they settle where they want to be? Seriously, I think most people who tout one box style over another never tried anything but what they have.
The 15" was a TC LMS-R and although output was astonishing, musicality was not a strong point. Switching this driver into a much, much smaller .5qtc sealed alignment made a huge difference in musicality, but required EQ to achieve flat response in room to 20Hz.
What size box + tuning freq did you use for the ported alignment?
I see that group delay is just horrible for the LMSr 15 in 6 cubes tuned to 20hz....basically flat. Its actually really good though if you have it in 4.2 cubes and tuned to 25hz.
Spinmonster, It was closer to 4.5 cubes tuned around 20-25 if I remember correctly. Was made using 18" cardboard sonotube acquired from a friend who got it from a construction job on condo's. Truly sounded one dimensional and flat, compared to my 12" 18Hz tapped horns it was no comparison...Other than output the TC just wasn't good in a EBS alignment.
Hi,
IMO: A closed box would be my first choice for use in a car but if ported I would pick a TL
b
Comparing the two first hand as I factually did (ported and sealed), I can tell you that I would never in a million years run it sealed over ported.
I built 3 boxes and ran 7 total alignments. Few can say that.
A 1.85 cube box at 25hz was the second worst sounding alignment 2.05 @ 25 being the worst I've heard for some time. 1.85 @ 27 sounded much better. 1.72 @ 27.5 really good. 1.4 @ 27 (best). Sealed was 1.05 (same as databass's test) and .85 with the smaller being really punchy and required to handle any power. The speed/control was not enough for me to give up the deep bass SPL and the distortion as the sub neared Xmax with the EQ to match the ported box was too much for me.
Do you have any plans to show the build parameters for this sub in a TL? I'd be interested in testing more theory. I really will build it.
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I think you are hearing harmonic distortion caused by excursion and driver size. To me, porteds will be cleaner (in a room) due to the braking of the port (see excursion graphs). A boosted sealed will make the driver really move, increasing blur. The less a driver is moving, the less the harmonic distortion. If your port size is smaller than it should be, the driver will also move more at tuning frequency, which makes more harmonic distortion. Having more drivers is another option (from a jbl tech paper, as you double the drivers, at the same volume/frequency, the excursion is halved, the distortion drops to 1/4). And lastly a push pull sounds exactly what you need (sealed for a car or a massive push pull tapped horn for a house). And subsonic protection really adds to more volume and cleaner sound.
Earlier someone was right. In a vehicle, you are resonating down low causing some notes to really keep ringing.
Since you seem to want massive output in a vehicle, I don't like them, but a bandpass can really get loud (like single 15" in a pickup at 150db).
Another option for a real room (not a vehicle) is the tapped horn stuff (but you need subsonic protection also). But the box size is really the limiting factor. The danley th50 (4 used in the chicago Imax) takes up a massive amount of space (2' x 3' x 4'). Box size is dependent on how low you go and cone size. Since about 2 years ago, thx spec'd 35hz cutoff for subs. 130db at 35hz is plenty plenty loud, versus 115db at 20hz. I was on a quest for 20hz till I had over (anechoic) 125db @27hz in my house.
You also may want to build some push pull slot loaded. My dual 12" 4.3mm xmax in a 27hz 6th order (little bigger than 4th, tuned and +6db boosted/subsonic at 27hz) in room smoked my buddy's 3 x 10" sealed JL somethings in his small pick-up. Cleaner, punchier, deeper, etc.
The more I crunch numbers, the more I'm not a fan of boosted/sealed. If small deep box is wanted, then it can work, given limited volume levels.
And if I ever build another subwoofer, it will only be push pull. It could be sealed, ported, 6th order, tapped horn, whatever. But it will be push pull.
Norman
Earlier someone was right. In a vehicle, you are resonating down low causing some notes to really keep ringing.
Since you seem to want massive output in a vehicle, I don't like them, but a bandpass can really get loud (like single 15" in a pickup at 150db).
Another option for a real room (not a vehicle) is the tapped horn stuff (but you need subsonic protection also). But the box size is really the limiting factor. The danley th50 (4 used in the chicago Imax) takes up a massive amount of space (2' x 3' x 4'). Box size is dependent on how low you go and cone size. Since about 2 years ago, thx spec'd 35hz cutoff for subs. 130db at 35hz is plenty plenty loud, versus 115db at 20hz. I was on a quest for 20hz till I had over (anechoic) 125db @27hz in my house.
You also may want to build some push pull slot loaded. My dual 12" 4.3mm xmax in a 27hz 6th order (little bigger than 4th, tuned and +6db boosted/subsonic at 27hz) in room smoked my buddy's 3 x 10" sealed JL somethings in his small pick-up. Cleaner, punchier, deeper, etc.
The more I crunch numbers, the more I'm not a fan of boosted/sealed. If small deep box is wanted, then it can work, given limited volume levels.
And if I ever build another subwoofer, it will only be push pull. It could be sealed, ported, 6th order, tapped horn, whatever. But it will be push pull.
Norman
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No issues with the vehicle ringing. My later posts in this thread noted that reducing internal volume to butterw/4 away from extended bass shelf got me the detailed sound I was looking for and it sounds incredible. EBS alignments are one note bass typically and lack detail.
I have the SPL I want with the extension I want with no compromises.
I initially used a 2 cube box ported to 25 and a 1.4 cube box tuned to 27 reduced group delay and gave me the punch and detail back.
I've never had a sealed car sub that got anywhere near the sound I want and in most cases I tried sealed and ported with each driver I ran. I think most people who try sealed (or what ever they initially try) never actually built a ported box to compare. They just go by what they read. I tried 7 alignments so I know what each sounds like first hand. 7db of EQ at 25/30hz which the sealed needs to make up the low end needs something like 4000 watts to hit the same spl as a ported box at 1000 watts. Good luck with that.
Just a thought; isn't is so that a driver can have T/S parameters that suit bass reflex OR sealed, with a few driver in between but not optimum for neither?
This might explain, partially, why the TC Sounds 12 perform best in bass reflex.
Another big reason is the preference of the listener and his experience in the past, which include even, dare I say, emotional memories with the DIY building and listening.
Math isn't everything, it's just a tool to help us build with less experimenting.
This might explain, partially, why the TC Sounds 12 perform best in bass reflex.
Another big reason is the preference of the listener and his experience in the past, which include even, dare I say, emotional memories with the DIY building and listening.
Math isn't everything, it's just a tool to help us build with less experimenting.
Hi,
sheesh... from the thread start I thought sound quality mattered most..and now that..Car-audio and SPL SPL and SPL.
jauu
Calvin
Oh Im sorry to have offended you and wasted your time with such worthless endeavors.
Seriously though, thanks for your input. I did get what I wanted and it sound much better. The sealed just wasnt for me in that it didnt have the balance I was after.
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