Originally Posted by coolrda
With MK's, w ere talking the same sub, amp, signal chain here but with different alignments. First you need to take a 50 or 60hz LFE sine to set both units to 85db, regardless if your using different subs, alignments or as in your case both. You need to take a narrowband sine@tune SPL reading i.e., Like my 6hz 0.1LFE CH only sine I always to test everything with. You used the Mean scale from the reading taking that are posted on the first page. Is that number a log or linear measurement? We need to remeasure this using VS and OM.
I'm sure MK calibrated his two configurations appropriately, but your right I assumed that he did.
Originally Posted by coolrda
MK didn't gain TR without his SPL being raised in that region. I know his SPL didn't change above the sealed alignments knee but it did most certainly after. His roll, even with an IB, was still probably up around 25-30hz. You put a wideband sweep on both and they will measure the same as it can't differentiate frequency. I've seen 15hz sines that have output several octaves above that contaminate SPL readings. That 9-12db that MK has gained is real SPL. Both speaker have the same loudness above the sealed turn but the SLLT rolls much less until the point below tune and it doesn't really matter after that. MK is gaining 6hz TR because of his 6hz SPL has increased accordingly. Even the smallest of FR changes can make a big difference in TR. We can test this very easily and I'll eat crow if I'm wrong.
Originally Posted by MKtheater
Having said this, Dom you maybe correct because I tested my IB VS while running the LFE channel 10-12 dB hot and the SLLT was flat which makes my 5-20hz 10-12 dB hot or the same spl and my VS was greater with the SLLT.
I'm pretty sure he posted his sweeps when he showed his VS data. The FR were very similar. And as MK states above, he ran his IB 10-12db hot, and his SLLT was flat, but yet the VS measured more TR. If you're questioning his test methodology, that's one thing. But I believe MK's test was accurate enough given the HUGE swing in TR combined with the other evidence we've collected on ported vs sealed to believe it is directionally correct.
Originally Posted by Scott Simonian
My twin LLT's were pretty close to what I get (deep bass) now with over twelve sealed 18's.
Anecdotal, but same theme.
What I think you're trying to say is that a sub's native response drives the TR, and that because of the ported subs native response has higher SPL around tune, it will naturally have more TR around tune....BUT, because the sealed native response starts to roll of much higher, we EQ the sealed native response to look like the ported native response (in MK's case, because it is tuned so low).
So now you have a ported subs native response and a sealed subs native response (+eq) looking the same (same SPL)....but the ported sub still provides more TR.
And then, in MK's case, he even ran his sealed 10-12db hotter, and the ported flat, and the ported TR was still more.
I've shown this with my test with my sealed 21 vs the FV15HP,
has shown this with his sealed Marty vs his ported marty, and then I demonstrated this again with the FV15HP vs the 1200D. Same SPL, same distance, more TR around tune.
You're killin' me
, I thought you were drinking the coolaid this whole time!