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If you didn't build something that wasn't a T-line, but called it one anyway, then no, I wasn't refering to you. Also, this thread has nothing to do with stiffling creativity, it is meant to cut the BS and give people correct information, that is why we are here anyway, right?

Aditionally, all the "order" refers to is the roll-off of the encloure. Standard vented box rolls of at an average rate of 24db/oct below F3. Hence 4th order. Add another 2nd order HP filter to the mix (like a SSF) and you now have a 6th order bass reflex aligment, which is what many people on this site are running for subwoofer alignments as we speak. They just probably never realized it. And band pass that is 4th order has a vented chamber that has a roll-off of roughly 24db/oct above and below the F3 points..... Seriously, alot of this stuff people are posting is pulled out of thier asses. And like M5 said, most of it causes more harm than good....

I wish more people understood this.

4th order ported = standard bass reflex design 4th order bandpass is when the driver is in the box and all sound comes from the port. A simple sealed enclosure with the driver firing into a ported one. Better transient response than 4th order vented, but a narrower passband.

you guys might like this guy.

10,000w unclipped.

The kerf really just changes the velocity and does very little to the overall length. As a general rule of thumb if you subtract half the flare radius from the length of the port (ie it shortens it), but again in your case this won't really affect things in particular since it isn't fully kerfed. (ie you only kerfed one side not all 4). Measurable, actual, and enough to worry about are all in play here and none of them will be big enough to change your result. You'll be close to your target tuning

I don't understand your kerfed question otherwise I'd answer it.

not sure when exactly this will happen, have to get trevor to build my box soon . Well slow it down with all the forum upgrades and get on it. J/K Mark. Your doing an excellent job here and I really appreciate everything you guys have done to keep this sight at the top of my favorites list. This concludes my thread crapping, now back to your regularly scheduled programming.

No money necessary. Your math is within a Hz. Sorry I didn't see the pic without the cross member before, just wanted to make sure In the case of designing boxes I don't believe in PM's, keeping things public is always a better option as others can pop in and say something.

The crossmember cutting the port in half is what has me confused. Not sure from a top view what that is doing. Otherwise your measurements are fine and you are indeed tuned low, but only by a Hz or so.

Seems reasonable for a 15"...not sure that the dimensions you posted in your picture match your target shape though.

I wish more people understood this. And they sure get all sorts of sand in their privates when you point it out to.

I am sorry, but one member, on a site this size and this old, does not make it as a whole look in any sort of manner.

What was the target shape for the port (ie L, W, H)?

The math? Haven't you designed a few? If so you should know it isn't trivial. I find this not so amusing that you are on here pushing members to build T-lines, you design one that causes a catastrophic failure of a driver, and still people follow along with your desires. Not sure which is worse your recommendations of them or the fact that people follow along and still want to build them. Chop take note, not the person you want designing you a T-line.... As for the math, what reading have you done and what do you need clarified?

I know, it is obvious from his (kirill007) 2nd post that he didn't understand that a 4th order vented box is not a bandpass (I never even mentioned bandpass) and that he completely missunderstands how a T-line works (look into the use of the word "tuning"). Pretty much everyone who believes this, and believes they have built a T-line (when in fact they have build a ported box with a huge port) will go on and on about it..... The whole point of a T-line is NON-resonant behavior and flat response with an enhanced low end. A proper T-line will never be more efficient (except the last octave, in which case they accell, but this doesn't help car audio SPL in the least) than a proper 4th order vented alignment... It is also appratent when someone post a picture of a "T-line" only to find that in fact, they have not built one at all. But like I said before, it doesn't matter what I say, lol...

It doesn't matter how basic the question is this is a forum, of course there website is gonna say it's true wattage that's why i ask. It matters if you can find the answer yourself. Thats annoying. If their site tells you its true specs, then why would you ask? Do you think theyre lying?

The Nightshade (12") has a Fs of 43 hz, and they recommend tuning between 30-40hz. And optimal tuning from Jacob was around 34hz i think, that's not really high i think. And i don't think the nightshade 12" can get as low as the HDC3 tuned to 34hz. Only basing on Fs you can't say how a subwoofer will play. (Sorry if you don't really understand it 100%, because i'm from Belgium ) EDIT: Why did i get -1 for the previous post? If i said something that isn't correct, please say so. (i think everything i said was correct.) I guarantee I'll go lower than a similar AQ setup tuned to the recommended 38 Hz. Your thinking about this the wrong way, the enclosure determined low end output in most cases. You might as well put an AQ in a prefabricated enclosure as that's around where they are tuned. They recommend tuning so high so their inefficient drivers can seem louder than they really are. I've heard many AQ setups and it takes a TON of power to make them play below tuning cause they are so damn inefficient. They recomend tuning at 38 Hz. because most people listen to music that peaks there or slightly higher. You are right in that Fs drops a few Hz. after break in and the spiders loosen up, but if they are as stiff as you claim the Fs won't drop much

Look the model number up on any search engine and you can find a link to tell you the specs. Just curious but why are you posting such basic questions that you can find on the net yourself?

If anybody says they can make an Icon take that kind of power they are nothing short of an idiot. There is a LOT more going on then just stacking spiders up for something to handle the power mechanically...when you really do not need it to handle more power in the first place. You simply need to learn how to control yourself Just being brutally honest with you. You will be MUCH better off selling the subs and purchasing something that is specifically made to take that kind of power. 99% of the power that you put into a speaker is burned off as nothing but HEAT

Full measurements would be helpful...

do it yourself, that way you'll know its right

Just as different vehicles are designed for different applications, so are speakers. I offroad all the time, and Ferraris have 4 wheels and are great cars... so why wouldnt I go rock crawling in that? Doesnt mean that the Ferrari is a POS, just that offroading or towing a trailer isnt the best idea for them. TS params indicate what application a sub should be used in. In the case of the BTL, the high motor force, low Qts, and small Vas indicate a ported speaker. A low motor force, higher Qts, and huge Vas often indicates a huge sealed application or IB specific sub. BTLs will not explode into flames in sealed, but as mentioned so eloquently above, they will sound like poop. Thanks, Scott

You are on the internet. Look it up dude. I can tell you from experience that they are all 750rms though.

The Bass Focus feature just allows you to adjust two sets of speakers (front L&R, rear L&R, left F&R, right F&R) at the same time. So, let's say you wanted to adjust both front speakers by 1ms. You would set the bass focus for the front L & R speakers to 1ms. So then your front left speaker would have a total delay of 2.5ms (1.5ms + 1ms) and your front right speaker would have a total delay of 1ms (0ms + 1ms). For example; In my system the both left and right speakers were installed in kickpanels. The subwoofer was the furthest speaker, and as a result I ended up delaying BOTH front speakers (front left and front right) by the same amount, .5ms. This delayed them BOTH to match the subwoofer. The Alpine Bass Focus is just the term they gave the feature that allows you to do the same thing a little easier, by allowing you to delay two sets of speakers at once. Using the bass focus to delay both front left and right speakers by 1ms would be identical in performance to manually adjusting both front left and right speakers by an additional 1ms. Make sense?

No. But it doesn't matter what I say, lol....

A true T-line will never be as efficient as a 4th order vented alignment. If you have a T-line that is more efficient than a 4th order vented alignment, chances are it isn't a T-line. The whole point of a T-line is to be very flat in amplitude response, it is about as good of a choice for SPL as a 2nd order sealed alignment.

did you look at ANY of his pinned topics? his contact info is everywhere lol payment and contact information - SSA Car Audio Forum and pricing is also pinned standard rates for ported enclosures - SSA Car Audio Forum

You don't need to build subwoofers for a living to understand that they recommend you tune high because the driver's Fs is ri-pucking-diculously high. I have some 7" mids here that have an Fs only 2hz higher than the Fs of the 12" HDC3. You're 7" mids are midbass drivers. (and a Fs of 43hz on a 12" inch driver isn't super high, and the 10 inch has a Fs of 41hz.) And remember the T/S specs aren't averaged between a few woofers, they took 1 woofer and took the T/S parameters without a break-in period.(Break in period lowers Fs quite a bit in a few cases.) No, an Fs of 43hz for a 12" driver is ridiculously high, and the reason the driver needs to be in a high tuned enclosure.

///M5 is a well respected member of this forum and has a wealth of knowledge to share. He has an opinion on something like yourself and he told you his opinion. You don't like it fine, but move on and let it go. If you like the AQ brand then by all means stick with it and support it.

beat you to it

If you want to build things Heavy Duty then fiberglass isn't the solution, but bracing is. Look up the matrix bracing on B&W's speakers and see how it should be done if you are truly into overboard mode. Resin will weaken mdf, not strengthen it. It will help you get louder perhaps, but regularly an unbraced floppy box is louder than a well built one from an SPL perspective.

Its a fart cannon. Not musical at all. As for the other comments. I don't bad mouth people, I do come off aggressively on comments though. But that is too fucking bad, perhaps if the comments actually were worth a shit in the first place I wouldn't. What I hate is what all the noob idiots are doing to the forum. It used to have a lot of well spoken questions and they all get answered well. Instead now we have a bunch of shit questions that NO ONE should try to answer because all they are doing is confusing the issue. Unlike the others who want to self promote and push what they have, I truly just want to help people solve their current dilemma and come up with a solution. All that it takes to get a good answer to this is a few extra seconds of proof reading before you post and making sure it meets the requirements that you agreed to when signing up on the forum. As for the "public forum", no its not. It is privately owned and run. You join here and make a promise to contribute and then you should follow your promise. I get really sick of all you asshats that don't try at all and then get all frustrated when someone doesn't support your post. Grow up, grow some balls, and do what you promised and you wouldn't feel that way.

he doesnt bad mouth people, he just has a strong opinion

You don't need to build subwoofers for a living to understand that they recommend you tune high because the driver's Fs is ri-fucking-diculously high. I have some 7" mids here that have an Fs only 2hz higher than the Fs of the 12" HDC3.

You know I still go into the technical section, and advanced section and re read, you always have to search and brush up on knowledge. No one person knows everything about this hobby.

ITS ON A PUBLIC FORUM THAT HAS THOUSANDS OF MEMBERS LOLOLOL I think I reserve the right to comment!