Originally Posted by Avus
BTW I am thoroughly enjoying this debate.
I am too - aside for ssabripo's weak debating style - which is why I keep wasting time here.
Originally Posted by TheEAR
You need an optimal driver ,for IB use drivers are the cheapest of any suitable design. As the BL can be very low compared to what you need fora sealed and ported sub.
You do not just close it and port it...an IB driver used in aported box would be far from ideal.
EAR, this has been said about 5 times now by 3 different people - please post the name and parameters of some (more than one) IB drivers not suitable for large and low tuned ported designs. Otherwise, why keep bringing it up? I'm not upset at all, I just want to see some of these mysterious drivers.
Originally Posted by ssabripo
Really sad to see you still think it is just a big ol sealed alignment
Please explain how it isn't. The two posts you linked to (from this own thread none the less, oh boy), don't explain anything to the contrary. I'm not trying to be crude or rude at all, but each time you post you get further and further from making sense. Please don't respond with some weak insult, cause I'm trying to be genuine.
Originally Posted by Avus
I did gain bass extension. As you said a driver can only put out so much air. With my 2 RL's max displacement was ~13L. With my IB I will be pushing 29L of air...an increase of 123%! That ought to really pressurize my room nicely!!
The person you quoted was talking about using a driver in a smallish sealed enclosure vs an IB, you are talking about two different drivers in different quantities. Also, for the second time, nobody but YOU decided to switch from using two RL-p18s to 4 Fi Q18s, so why put the onus on the alignment? Nobody stopped you from building a quad Fi Q18 SLLT but you.
This seems completely the opposite to me. My IB will run much deeper than the dual LLT's and offer more output everywhere except right at tuning.
In this quote, I was comparing a set number and type of drivers in an IB vs a SLLT, you are misreading and going down a side path with your responses.
C'mon, different drivers are suited for different enclosures as everyone knows. The RL is over kill for an IB install IMHO. IB installs don't need that much motor force which enables us to get the drivers much much cheaper.
Same to you as I said to EAR, show me these mysterious drivers. You and EAR might be shocked to learn that a large ported design also doesn't need or want high BL, as the "large" enclosure means a lot of volume. You guys are off base in your assumption.
The build materials don't cancel themselves out. The binding post and such do which is why I did not list prices for those but wood and the sonotube is much more $$ for the LLT than building a manifold out of some mdf and osb. Plus, the sonotube takes much more time to construct vs the manifold not to mention getting the damn tube home!
If you want to be fair, you should at least try to maintain the same build standards between the two designs, which is why I mentioned you'd need a really thick baffle to match the rigidity of a 3 layer endcap for a single driver. But even if I gave you that one, if you knew you had an adjacent space, nobody stopped you from going SLLT. Nobody said you had to use a tube enclosure, the adjacent space would have worked just fine.
As for EQ, why do you think that the IB's somehow "require" an eq but LLT's don't?? I could say that an LLT needs it more to cut the lower freqs so they don't bottom below tuning. Seems silly.
For your first part, because it's the truth - IB will have a rolloff whereas a LLT will stay flatter longer. If you want to match the FR linearity of the LLT, you will need to boost the low end of the IB. For your second part, that is false, and has been a weak out some have used for a while. Nothing silly about it.
Originally Posted by penngray
Sorry that isnt true.. its costing me more to build two ported boxes then it did to build an IB. I originally built my IB with drivers that cost $90 each, 4 18" driver did cost $100 more then 1 TC2000 15". I upgraded too 4 Q18s for $1000 (new ones are EVEN cheaper). IB drivers are REALLY CHEAP. Check out the comparison chart....
Again, if you already had an adjacent space, you could have just gone SLLT - nobody is forcing you guys to build a discrete enclosure except for you. Then you are trying to use that as some type of reasoning. And now I say the same to you as EAR and Avus, show me these mysterious drivers that won't work in a ported application. It was you who chose the drivers, nobody forced you to pick driver X over driver Y, you could have used other, cheaper drivers. It's not really a good argument.
a ported box.....ugh. Routing, re-inforced bracing, fitting the port, finishing the box and so on. Much more time. Also have to figure out port size and length, Box CF and so on. None of that is need in an IB.
I agree that if you want the simplest build possible in terms of actually having to do something (this is DIY isn't it?), an IB is pretty easy - and I think that's why a lot of people pick it. But if you spend a few more hours, you get more performance, and to me, that is worth it.
You can not talk about cost unless you add this into the mix. I suspect you will ignore it like you do with any sort of cosmetic value but its there for the rest of us.
Maybe DIY isn't for you then, I dunno. Most other DIY owners tend to like working on such things. That's why you constantly see them working on one thing or another, even if they don't need it.
BTW, you havent prove anything either you know so your Nothing to the contrary has been proven by anyone opinion holds no water WHEN EVERYONE else disagrees with you. The burden of proof is actually on your lap not ours.
What exactly do I have to prove? That porting creates lower distortion, more low end output, greater FR linearity, etc.? It's already been proven. You can find all the detaile dmeasurements you need over at hometheatershack from Ilkka. What else do you need to know?
I cant believe there is actually an arguement here
You need to understand the basics first, then it will make more sense.
Originally Posted by bosso
Please show me Ilkka's test of any ported sub that shows 'greater FR linearity and lower distortion'?
You already know where to find it. TC2k ported is superior to TC2k sealed. If you care more about <10hz than you do >10hz, more power to you, but no need to ramble on about some left field concept.
As for the doubting of air spring distortion
, it comes directly from Linkwitz, the guy who seems to be everyone's hero. The smaller the box and greater the displacement of the driver, the greater the air spring distortion. You can find it in his "closed box" spreadsheet here
- he uses the equation: air spring distortion = 0.014*(Sd*Xmax) / enclosure volume.
I need help with this one. Box coloration? Exactly what sort of coloration does a box contribute vs anchoring the baffle to a wood frame structure?
I agree with bosso here, as long as an enclosure is well built and braced, it will not impart much, if any, coloration. A 1.5" thick, ~78" x 22" IB baffle trying to maintain rigidity while holding four high excursion 18" drivers in array on the other hand, well, I wouldn't be so confident. If I were to mount 4 high excursion 18" drivers in array to a single baffle, that thing would be at least 4.5" thick before bracing.
Reduce the rear chamber volume.