2 hz tuning - pros and cons - Page 8

I've covered all of this. You can make the box any size you like as long as you keep the same tuning. Just like a sealed box, just use eq to get it where you want it. I only used the size because it provided an easy comparison to a known product.

I am not ignoring vent noise, in fact I've simulated the hell out of the situation with several different programs.

Pipe resonances have been shown IN EVERY SIMULATION done by both you and me to be a non issue, less than 1 db ripple.

I know you don't think the compromises are worth it, that does not invalidate the simulations. I agree that compression testing will very likely show a situation worse than the simulation but no where near as bad as you seem to think.

The normal course of design for ANY design is to simulate with acceptable velocity limits as predicted by the t/s simulator, 10 or 17 m/s are popular limitations set forth by diy'ers. You may or may not want to check the result with Flare It at that point. This is what everybody does all the time, how come it's not valid in this case?

I seriously don't care if the design is worth it anymore, I'm only arguing that it will work as simulated, just like every other sub works as simulated.
Edited by diy speaker guy - 12/11/12 at 1:26pm

What's up guys? A real world example has you stumped as you try to figure out how to argue against 45 m/s velocity coming out your little tiny nose hole?

(No doubt high compression situation but it does NOT revert to a sealed hole even at WELL over 10x the core velocity of the hole.)

I fielded a constant and consistent barrage of questioning, do me the same favor. It's too easy to argue against something (a simulation) which I have no practical way of proving by measurement, not so easy to argue against a common natural occurance that has been measured.
Edited by diy speaker guy - 12/11/12 at 1:44pm

Not sure why you think the combined simulations are not taking this into consideration. The arguement here (at the extreme end) is that exceeding the core velocity in Flare It will very quickly cause the hole to not pass ANY air. The sneeze example shows this is not true until you get well past at least 10 x the core velocity red line in Flare It.

Stuffing the port blocks the air flow. If you use a little stuffing in a port you get the same effect as stuffing in a transmission line but if you increase it, it will eventually completely block the airflow.

Post 137 is the valid comparison, not the graph you are looking at.

Xmax limited max SPL at the lowest frequency of interest is the only thing that matters, and the graphs you refer to (at same power level) are not a valid comparison in that respect.

Noah is correct (in the context of this conversation) and you are not.

If equal power simulation was relevant then you would be correct.

Why don't you? Probably for the same reason I can't. There simply is no affordable supporting equipment to set this up and measure properly.

Why is everyone so scared to even mention the sneeze? It invalidates all of your collective arguments in one fell swoop.

EDIT - posted too soon.

SO you are saying the power of your lungs is several times more powerful than the Bl of the two 18 inch drivers?

Resonance has nothing to do with this. It's a core velocity issue, and it's not an issue. The arguement has been stated that high enough velocity will effectively seal the hole at levels shown in my sim, this will simply not happen.

This thread has no point anymore. I've provided proof with simulations and real world measured occurances. No one has effectively argued any of it despite pages of conjecture and speculation with no supporting evidence. Every link that has been posted to disprove what I'm saying actually backs up my POV.

Neither side is gaining any ground. I will agree to disagree and stop posting completely if everyone else does too, with the agreement that we absolutely do not agree with each other.

As stated in post 1, I wanted to discuss the pros and cons of the simulation, simple as that. The information in this case is several times more valuable than the finished product, which I was only halfheartedly considering building in the first place.

I apologize for my passion and for trying to answer each individual point. If you (and at least one other person) think that's trolling I will gladly leave avsforum for good.

The lungs and nasal passage are also a resonant system.
Edited by diy speaker guy - 12/11/12 at 3:16pm

As stated in post 1, and about 60 times since then, this is not supposed to be able to play 2 hz. It was designed to be tuned so the problems would be below the rolloff of the supporting equipment. Why is this so hard to understand? There is absolutely no problem above 5 hz, and I'd argue even lower. The signal chain IS the high pass filter.

AFAIK, ALL valid comparisons compare xmax limited max spl at the lowest frequency of interest. Comparing equal power does not reflect that and I can't see any usefullness to comparing that unless you are limited by the amp power and not xmax.

But let's just stop now. If I'm seen as a troll I don't want to continue but find it very hard to ignore posts directed at me.
Edited by diy speaker guy - 12/11/12 at 3:00pm

I turned down the power on the sealed so neither one of them would pass xmax until below 3 hz. As mentioned, it might be a bit more fair to add a bit more power to the sealed since it doesn't really need to go that low, but you still can't compare same power if you want to figure out how loud either will be at 4 or 5 hz if one of the designs can't handle that power at that frequency.

Well, I surely do not want to expand the topic, I'm trying to narrow it or end this completely but I'd be happy to discuss this by email or PM if you like. Post 137 shows my opinion on the matter. I've given all details of exactly what I simulated so you can recreate that if you like.

I agree with that completely but hopefully with a bit more scientific rigor than Mythbusters.

Did you read post 1? I never said I was going to build it, I wanted to discuss a simulation. Many people say the sim is wrong and that is fine and welcome but I was hoping to see some evidence.

I did mention the drivers were in my price range now and that's why I simulated this in the first place but I never said I was going to buy them. I did get a bit excited at one point around page 2 or 3 until you guys beat the will to continue living out of me.

If this is not the appropriate place for discussion of theory please ask a mod to delete the thread.