Best infinite baffle subs? - Page 2 - AVS Forum
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Old 11-05-2013, 12:25 AM
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"Even though Qts may look good for the application, this stiff suspension still makes the driver roll off very quickly, and it is not efficient. A large amount of power still needs to be applied to the driver to compensate for this rolloff and lack of efficiency. This means the infinite baffle then loses its most important benefit over a sealed box."

it would seem that way, but then we run into this problem...

red line is the lms ultra 18 which has a medium stiff suspension and a monster motor, low q, and works well in a very tiny box. it is as mark would say, "not bass efficient".

the blue line the ib318 infinite baffle subwoofer, high q, works well in infinite baffle. it is as mark would say, "very bass efficient".

both driver plopped into a 500 cubic foot cabinet (effectively an i.b.) and eq'd to have the exact same response. the lms should require lots more power right?



wrong! below 22hz the lms is actually soaking up less power than the ib318. eek.gifeek.gifeek.gif


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Old 11-05-2013, 09:02 AM
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Soaking up less power? Lms is red right? If you integrated both those function from 10-80hz and subtracted blue from red, you'd have a positive value, meaning over that frequency range, the LMS is using more power.

*edit* wow missed the whole <22hz comment.

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Old 11-05-2013, 11:07 AM
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Thanks for that, quite interesting.

Also, in my experience it would appear to me that the IB3-18 doesn't enjoy the native extension that other such IB drivers do, ie., the AE IB15, or whatever it's current designation is. The Fi is a nice value driver, great displacement/$, but similar IB builds utilizing drivers more natively adept down deep (RE XXX, AE) do seem to require less compensating EQ/power etc.

It will be interesting to see what response MK realizes down into the infra range. He'll benefit from some nice cabin gain for sure (low cubes, rigid boundaries).

Thanks for the sims

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Old 11-05-2013, 11:22 AM
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Quote:
Originally Posted by FOH View Post

Thanks for that, quite interesting.

Also, in my experience it would appear to me that the IB3-18 doesn't enjoy the native extension that other such IB drivers do, ie., the AE IB15, or whatever it's current designation is. The Fi is a nice value driver, great displacement/$, but similar IB builds utilizing drivers more natively adept down deep (RE XXX, AE) do seem to require less compensating EQ/power etc.

It will be interesting to see what response MK realizes down into the infra range. He'll benefit from some nice cabin gain for sure (low cubes, rigid boundaries).

Thanks for the sims

I am assuming the IB3 will be similar to the Q 18 which rolls off like the UXL just not as clean at max excursion. D-B shows them almost even long term max except for the inductance peak from the Q18. Again, clean is or won't be a problem so I wanted displacement. The AE driver in my sims reaches over x-max at 25hz with 200 watts while the Fi still has plenty to go. The AE did have more spl at 10hz than the Fi at 200 watts but only one can be used with 200 watts. The FI can double that for 3 dBs more too. What am I missing? If 8 AE would have given me more spl down low than the 8 Fi's I would have went that route since the price is similar.

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Old 11-05-2013, 12:00 PM
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Quote:
Originally Posted by MKtheater View Post

I am assuming the IB3 will be similar to the Q 18 which rolls off like the UXL just not as clean at max excursion. D-B shows them almost even long term max except for the inductance peak from the Q18. Again, clean is or won't be a problem so I wanted displacement. The AE driver in my sims reaches over x-max at 25hz with 200 watts while the Fi still has plenty to go. The AE did have more spl at 10hz than the Fi at 200 watts but only one can be used with 200 watts. The FI can double that for 3 dBs more too. What am I missing? If 8 AE would have given me more spl down low than the 8 Fi's I would have went that route since the price is similar.

You're not missing anything. All I intended was it would be interesting to see that sim with an AE driver.

You got the right drivers, displacement wins, when one has power and EQ tools, ... you'll have more Sd, more Vd. Eight 18s will barely be moving 99% of the time.

Utilizing the 8 18"s, with massive amounts of displacement, keeping both excursion and VC current low, you're lowering the non-linearities including linearizing Bl(x), and lessening any inductance variation related harmonic and intermod distortion by again keeping both power and stroke to a minimum, Le(x), Le(i).

No regrets MK, the baffle wall IB should be stunning, both measurably and subjectively.
Quote:
Again, clean is or won't be a problem so I wanted displacement.

I'd say you've increased your relative* Vd capability by 2x-3x, compared to what you had before.

*as I've shared before, I believe the eD drivers rated Sd was generous. The piston area is really small relative to other drivers of a similar trade size. Hence the 2x-3x comments. Admittedly, speculative.

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Old 11-05-2013, 12:11 PM
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Originally Posted by BrickTop View Post

I did a small workup of all the high excursion large diameter drivers I could find information about and the Fi IB318 ended up at the top of the list for displacement per $, followed very closely by the Stereo Integrity 18". The SI18 is not due in until June and the per driver displacement is about 70% of the Fi, but has a high bang for buck factor.

They are out of the second shipment of 18's? I thought Nick still had plenty!!!

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Originally Posted by staffcurtis View Post

I am going to try the IB route myself. I am building a new home, and am positioning one or possibly two manifolds above the screen in front of my HT between the mains. I love extreme bass, so which subs do you guys say work best? I am hearing everyone loves the FI IB318's, but how do they compare to the Stereo Integrity HT18 subs? the HT18 seem to have a low QTS, but I've heard good things about them from forum posts. Any input would be great.

Thanks

Not sure if you are ever up in the hills, but I am fitting to have two of the RE's in a manifold IB for a little while if you want to have a demo. I also have 4 (maybe all 8 back in by then) of the SI' in dual opposed sealed boxes so you could get a chance to listen to both really smile.gif

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Old 11-05-2013, 12:48 PM
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Quote:
Originally Posted by FOH View Post

You're not missing anything. All I intended was it would be interesting to see that sim with an AE driver.

You got the right drivers, displacement wins, when one has power and EQ tools, ... you'll have more Sd, more Vd. Eight 18s will barely be moving 99% of the time.

Utilizing the 8 18"s, with massive amounts of displacement, keeping both excursion and VC current low, you're lowering the non-linearities including linearizing Bl(x), and lessening any inductance variation related harmonic and intermod distortion by again keeping both power and stroke to a minimum, Le(x), Le(i).

No regrets MK, the baffle wall IB should be stunning, both measurably and subjectively.


I'd say you've increased your relative* Vd capability by 2x-3x, compared to what you had before.

*as I've shared before, I believe the eD drivers rated Sd was generous. The piston area is really small relative to other drivers of a similar trade size. Hence the 2x-3x comments. Admittedly, speculative.

Oh OK, sounds good then. I measured my eD's and they were 12 inches from surround to surround. The also had a bigger surround so yes probably smaller than what eD spec'd them to be. If we used the same way they did the IB3's would be 18.5 woofers while the eD's were 13's. I thought I had 36 liters before but it was much closer to 30 liters. 2.5 liters rather than 3 liters per drive. Still kicked butt though but again 1820 cubes with 12 and clone power.

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Old 11-05-2013, 03:59 PM
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Fwiw;
Here is an image I found of the eD driver. I think it's one of the most bad ass looking drivers I've ever seen, really, it's gorgeous. But, examining the ratio of cone radiating area, to overall trade size, I've not seen any driver with such a huge ratio of surround/cone. I think this adds to the appeal, at least in my case.

By my rough eyeball, the above image appears to show the cone-to-trade size ratio of about 63%-65%. I suspect the cone is about ~8" across.

"Still kicked butt though but again 1820 cubes with 12 and clone power."

I know, I saw the measurements, I know the context of your experience. All those, powered by the clone, yeah, superb state of the art capability.

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