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View Full Version : 4th order Bandpass, whats the point



DFW40
02-03-2007, 12:50 PM
What advantages does the 4th order bandpass have over a regular sealed box. I built a 4th order and it was about the size of a large ported box with half the output. It sounded good but was a bit peaky compared to a regular sealed.

DFW40
02-03-2007, 07:20 PM
Anyone??

lookitsjim23
02-03-2007, 07:22 PM
maybe you didnt build it right.. and it is peaky..thats what they are...sealed is different completely

rpfuror
02-03-2007, 07:34 PM
mmm..
The main point of doing a 4th order is to get the transfer/accuracy of a sealed enclosure with the gain of a ported.

When designing a 4th order you can determine gain in dB or base it off of your lower end of the passband (lower cutoff freq) all based on the driver parameters. So there could be many reasons you are not getting the output you what; the pass band could have been to tight/low/high or you could have had a very low gain. Also, not all drivers work well in this type of design.

80INCHES
02-04-2007, 02:31 AM
What advantages does the 4th order bandpass have over a regular sealed box. I built a 4th order and it was about the size of a large ported box with half the output. It sounded good but was a bit peaky compared to a regular sealed.

slap more power and set the xover to 80hz and the ssf to 20hz and u will be fine

80

DFW40
02-04-2007, 11:56 AM
mmm..
The main point of doing a 4th order is to get the transfer/accuracy of a sealed enclosure with the gain of a ported.

When designing a 4th order you can determine gain in dB or base it off of your lower end of the passband (lower cutoff freq) all based on the driver parameters. So there could be many reasons you are not getting the output you what; the pass band could have been to tight/low/high or you could have had a very low gain. Also, not all drivers work well in this type of design.

Do not get me wrong it sounded good once I got the crossovers adjusted etc but I did not get the extra output of a 4th order over a regular sealed box by any means. I usually have my subwoofer output set on 3 with the max being 6 with a ported box but to get the same output on the 4th order I had to bump in up to 5/6. It did have a nice tighness and more accuracy like any sealed box but not the extra output which means to me that I just built a bigass sealed box. I guess another advantage is that it is a sealed box that you can tune exactly to your likings vs the regular sealed that you can make bigger or smaller but that is about it. I uaullly need a decent amount of trunk space so the "advantages" did not really outweigh the disadvantages. 80 inches designed it well and it was built to spec.

rpfuror
02-04-2007, 07:31 PM
I believe that 80 knows what he is dong, not questioning that...

80... u mind me asking what the gain and passband was on the box?

If the box was designed to give you an accurate responce with in the passband I would expect that the gain would be lower. Not all drivers can fall with in both, the desirable passband and increased gain.