Originally Posted by notnyt
Ah, I missed the data-bass entry for it. I even looked for it.. ah well. looks pretty good. I'm not sure how accurately you can model such a long/small port with these apps.
Again, this conversation has be completely confused. Can you (or Mark, or anyone) explain how MJK's transmission line
mathcad worksheet can't simulate long ports? From every account I've seen this software is amazingly accurate in all respects that people actually measure. I'll admit it's hard to measure port velocity at home but I've never once (in all the years I've been reading about simulation software) heard anyone claim that this software (or even any of the less softwares available) is this far off in predicting port velocity.
You guys seem to be getting all caught up in the fact that the port is long and narrow but this is EXACTLY the reason MJK made this software - to accurately simulate different shapes and sizes. (And there was Akabak 20 years ago.) Unless I'm missing something (and I freely admit I might be) this is just a math equation and the simulation software I used adresses all the important aspects. It seems too good to be true (I was surprised to see this myself) until you think about it for awhile. As you tune lower, you can get by with an increasingly small diameter port and still maintain the same port velocity, I hope we all realize this. If you don't believe that you can model it yourself in your favorite simulator, I can clearly see it every time I tune a design lower and lower. By the time you get down to 2 hz you can get by with a very small diameter port with acceptable velocity, I'm not sure why (or at what point) you guys think the model breaks down, but I can't see any reason why it would not be accurate at all frequencies.
It still seems a waste to me, when you can tune to a frequency that will give you more benefits in a range you can actually notice. Again, just my $0.02
Yes, thank you, everyone has made that incredibly clear. But can I ask you something? Did you guys give the guy with the fan sub (member here) this much negative feedback on his decision to have a (very expensive) device for just this purpose? Did you give Imagic (member here - Dub King) this much hassle about making music that plays this low? Who harasses the guy that makes the LF content movie lists and posts spectrograms? If I recall correctly, these were all very cool things and universally and wholeheartedly embraced on avsforum until the exact moment that I posted this thread. WHAT IS GOING ON HERE? I realize Krypto took a bashing for doing what he did, but what he was doing was not really practical by anyone's standards. And even so I don't think anyone could argue that he probably would have been an interesting guy to know and despite the overzealous nature of his projects I'm sure they would have been incredibly cool to experience in person.
This is an intellectual excercise, a conversation about simulation software and the validity of it's predicted results and one design in particular. I may not ever build anything even similar to this but I find the exploration of the idea INCREDIBLY interesting. For the sake of arguement let's say that if I did build this thing I would make 2 of them (4 drivers total) and I would put them directly behind my couch, about 12 inches away from my head. In this situation there is no need for crazy high output above 16 hz but it would be SUPER COOL if I could get down to at least 5 hz flat with a single Behringer EP4000. My simulation shows it is more than just possible, it is now affordable even for me. Why would I not want to do that? (Please don't answer that - this is not supposed to be a conversation about tuning preferences.)
This is very much similar to asking about a specific tractor schmatic and being told tractors are stupid, cars is where it's at.