Best infinite baffle subs?

Originally Posted by rr14 

What frequency would you suggest I hp them?

Originally Posted by S_rangeBrew 

I respectfuly disagree with my fellow IB user. I have 4 ib3s in a 1800 cf room. They are not even close to bottoming. Also i use a crown xls 5000 for 500 watts per driver. No problems. Plenty of 5 hz sound.
Get what you can and leave room for expansion.

Originally Posted by FOH 

No problem.

When I bought mine, I free air tested them, individually, in pairs, and in a group of four. With a Behringer EP4000, as I raised the drive level, I could ease them into bottoming prior to full power in both the 4ohm config (one amp channel per 4ohm driver), and the bridged 4ohm config (two sets of series connected drivers, paralelled across the amp. In both scenarios, I could tap the VCs on the back plate.

The EP4K puts out 650w per channel into 4ohms, and ~1600w-2000w into 4ohms bridged.

I tested them once fully installed too, in various configs, even with a second EP4K,..to allow one driver per channel operation. The only config I can operate in without worrying about bottoming, is series connected 8ohm loads,...which is 450watts per channel, 225watts per driver.

I can't explain the differences, however I believe you. Something is influencing the difference. Maybe the signal chain possesses some roll-off, or the drivers are different. A year or two ago, I inquired specifically with the designer/builder at Fi (Nick I believe), he stated there's no differences in either of the two versions of IB3-18s with regard to the excursion capability, Xmech, Xmax, clearances, etc. They re-tooled and thus, I was interested in what was going on wrt the driver.

No biggie, as it's still plenty strong

Originally Posted by S_rangeBrew 


BTW, I finally figured out how to reproduce the missing "punch" that box subwoofers have and IB subs lack. Simply playback a quality recording of a box woofer playing a song, and the IB will reproduce the "punch" (ie, distortion) of the box subwoofer perfectly. It's kind of irrefutable evidence of the superiority of IB. BTW, I disagree vehemently with Mark Seaton and others who posit the clarity of IB can be reproduced with box subs of equal displacement.

Which is why I feel mtbdudex shouldn't sully his awesome room and it's fantastic IB with lowly box subs.

Originally Posted by S_rangeBrew 


BTW, I finally figured out how to reproduce the missing "punch" that box subwoofers have and IB subs lack. Simply playback a quality recording of a box woofer playing a song, and the IB will reproduce the "punch" (ie, distortion) of the box subwoofer perfectly. It's kind of irrefutable evidence of the superiority of IB. BTW, I disagree vehemently with Mark Seaton and others who posit the clarity of IB can be reproduced with box subs of equal displacement.

Which is why I feel mtbdudex shouldn't sully his awesome room and it's fantastic IB with lowly box subs.

Make sure that the main loudspeakers are not high pass filtered as they act as additional low frequency sources, which is desirable.

"First setup the mains and the nearest sub [(the sub nearest to the mains)]. Set your spectrum analyzer to a very low bandwidth but not less than 200 Hz and fairly long averaging time. This will yield a very long average of the sound signal. Take your mic and move it through large spatial positions near but arround the prefered listening position. Be carefull as small bumps of the cable can generate large erroneous signals into the mic. The sweeping has to be smooth. When the analyzer has completed its run you will have a plot of the frequency and spatial averaged low frequency sound field. Try adjusting the sub - never adjust the mains - to see if you can get a better response by changing the gain, the low pass point, the phase and or delay if you have it. The bass should be sagging slightly at this point since you will be adding in two more subs.

Now add in the next closest sub and repeat the entire procedure again. You should be able to improve upon what you had before. If not try turning off the first sub and setting the second one optimal and then add in the first sub. If you still can't get a better response with two subs than with one then you will need to move one of them. You need to get an improvement from the second sub or something is wrong.

Now repeat this process with the third sub. The third sub, when you are close to it should barely be audible. If it is loud, then once again, something is wrong. It should only be filling in holes at this point and not adding any actual level. The level after two subs should be about flat or possibly a slight rise - based on preference. I find a few dB rise at the low end is desirable for best effect.

With the three subs things should be quite smooth when spatially averaged. You can now use any EQ that you have to make a final flattening of the response, but these bands should never be more than a few dB. When you are done, if things go as they usually do for me, your should have a spatial average of about ± 2-3 dB. This can take several hours so don't be impatient. [...] Make sure and write down all the settings!!

Originally Posted by audiovideoholic 


Huh?

Originally Posted by S_rangeBrew 

How big is your room? Mine is on the small side, less than 1800 cubic feet and sealed. I suspect my room gain is quite large.

BTW, I finally figured out how to reproduce the missing "punch" that box subwoofers have and IB subs lack. Simply playback a quality recording of a box woofer playing a song, and the IB will reproduce the "punch" (ie, distortion) of the box subwoofer perfectly. It's kind of irrefutable evidence of the superiority of IB. BTW, I disagree vehemently with Mark Seaton and others who posit the clarity of IB can be reproduced with box subs of equal displacement.

Which is why I feel mtbdudex shouldn't sully his awesome room and it's fantastic IB with lowly box subs.

Originally Posted by S_rangeBrew 

How big is your room? Mine is on the small side, less than 1800 cubic feet and sealed. I suspect my room gain is quite large.

BTW, I finally figured out how to reproduce the missing "punch" that box subwoofers have and IB subs lack. Simply playback a quality recording of a box woofer playing a song, and the IB will reproduce the "punch" (ie, distortion) of the box subwoofer perfectly. It's kind of irrefutable evidence of the superiority of IB. BTW, I disagree vehemently with Mark Seaton and others who posit the clarity of IB can be reproduced with box subs of equal displacement.

Which is why I feel mtbdudex shouldn't sully his awesome room and it's fantastic IB with lowly box subs.

Originally Posted by JapanDave 

If your IB sub is lacking that 'Punch' then your IB sub is not doing what it is supposed to do. Sorry.