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Discussion Starter · #1 ·
Per the title...

I have four Stereo Integrity HT 18 D4 for IB install via two manifolds. How much RMS power can each driver "safely" handle (using both voice coils)? Estimates are okay!

OR... What is an acceptable rule-of-thumb regarding "rated specs" (which are probably assuming enclosed) vs. IB? 25 percent, 50 percent, 75 percent? Estimates okay!
 

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Welcome to HTS!

That's a tricky one to gauge safe IB power levels. You essentially have to ignore the rated power limits for the driver and model it. Although, Stereo Integrity supposedly suggests 600W as a mechanical limit for typical applications. The only way to be sure in any application is to model. I just put together a sub using an SI 18 D4 and I measured the driver parameters after some mild break-in. With my measured parameters and spec sheet Mms, modeling shows they would not exceed xmax until below 16Hz with 250W. The would have a -3dB point of around 30Hz, -6dB at 20, -10dB around 13Hz, and output a boat load of SPL.
 

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Discussion Starter · #3 ·
Welcome to HTS!

That's a tricky one to gauge safe IB power levels. You essentially have to ignore the rated power limits for the driver and model it. Although, Stereo Integrity supposedly suggests 600W as a mechanical limit for typical applications. The only way to be sure in any application is to model. I just put together a sub using an SI 18 D4 and I measured the driver parameters after some mild break-in. With my measured parameters and spec sheet Mms, modeling shows they would not exceed xmax until below 16Hz with 250W. The would have a -3dB point of around 30Hz, -6dB at 20, -10dB around 13Hz, and output a boat load of SPL.
Thank you!! These will be EQed fairly flat down to 10Hz. So a SWAG is maybe 300w RMS per driver (both VC driven)?

I don't want to underpower these but also don't want to buy 4x the amp power I can safely use.
 

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Sure, 200-400W/ea would be good especially with EQ involved. If you get a smart enough amp you can always set up a limiter, but you'd need to coordinate that with your EQ to make sure the limiter follows what's safe for the excursion and not extra power consumed with EQ. It all depends on how much EQ you need to get to 10Hz, your room will influence that a lot. You may not even need any!
 

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Discussion Starter · #5 ·
Sure, 200-400W/ea would be good especially with EQ involved. If you get a smart enough amp you can always set up a limiter, but you'd need to coordinate that with your EQ to make sure the limiter follows what's safe for the excursion and not extra power consumed with EQ. It all depends on how much EQ you need to get to 10Hz, your room will influence that a lot. You may not even need any!
Thank you. So 300w per driver is safe for IB with these woofers. That's 600w per pair. I haven't yet decided between Adcom GFA 555 or Behringer EP2500 amps. I have past experience with the Adcom amps and love their taught/controlled/dynamic bass reproduction but have no experience with the Behringer amps. I think I want to avoid class D amps due to their low damping factors because I hate mushy bass.

The room is 16x24x9 feet and doors can be closed to "nearly" seal it closed so room gain will begin at approximately 50Hz. Three pairs of Stereo Integrity 18 D4 will fill the low-end (actually, two woofers are another brand but their T-S parameters are virtually identical). The front two corners of the room will each have a pair firing through the ceiling and the rear pair will fire from behind near the floor from under the stairwell.
 
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