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Natural rolloff vs. LT same Q
Natural rolloff vs. LT same Q
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Old 27th August 2005, 08:32 PM   #1
Cro maniac is offline Cro maniac  Croatia
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Natural rolloff vs. LT same Q
Default Natural rolloff vs. LT same Q

The time has come for me to build myself a new sub, and I have some doubts.

If I take one driver and put it in the Q=0,5 box, and then take the same driver and put it in the Q=0,9 box and then use Linkwitz Transform and equalize the second box to Q=0,5, will this two boxes sound the same ?
I expect them to sound different, but Winisd tells me they are the same.

My room as relatively small ( 4m x 3m ), with lot of room gain, so sealed box with Q of 0,7 or smaller would give me flat response down to 20Hz.
Many people use LT to get down low, but I don't really know what are the advantages of using LT except possibility of using very small box which is easier to make very stiff. In smaller box, distortion of air compliace is bigger, smaller boxes need more power which leads to more power compression in drivers, so I'm wondering is LT worth
the benefits from it.

I plan to use Focal Polyglass drivers because they sound good enough for me and look great.
My initial plan was to use four 27V1 drivers each powered with 100W amp and mounted in about 30 liters box, but then I realized that two 40V1 drivers cost less than four 27V1 and give me 75% more displacement (or 5dB louder). The problem with 40V1 is using undersized motor, so for them the box would have to be too big (300 liters), or I would have to put them in 50 liters box and use Linkwitz transform circuit and push each driver to its thermal limit with 400W amp to use all available Xmax.

Please help me with my dilemma.
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Old 31st August 2005, 02:06 AM   #2
mike.e is offline mike.e  New Zealand
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Xmax is only SPL potential.

Post up a screenshot of a few alignments,sealed,sealed with LT etc.
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