Bandpass vs ported

[Smanleyman 15]

Ok I've been doing a lot of research on standard 6th order bandpass boxes, and haven't found enough information to decide if its better than standard ported for spl. If I tune a 6th order with a very narrow high output passband, such as 39hz rear and 44hz front, or in this general region, will it be louder than a ported box with a similar tuning?

From what I've seen the 6th order will boost output higher, but it strains the subwoofer more and lowers power handling, so it has more output but you can put less power to it so they balance out... I want to try one out but if you guys think it wont be louder than just ported for spl use only then it's not worth trying.

Also I was wondering on tuning for either box, Ill be using a 10" Fi Bl with fs 41.5, so should I tune near this or try to figure out my cabin gain peak, which I have no clue where its at but it was 36hz from a 31hz box with a q15.. so I know both the box and sub lowered that peak...?

I guess just for flame prevention I'll mention the vehicle is a 2000 honda accord sedan, I have plenty of space to work with for either box, it would only be for spl use so my goals are LOUD, and i'll have a separate daily box...

Thanks ahead of time for any input guys...

[KU40 173]

The 6th order will have higher efficiency than a ported box. I've never heard of a bandpass lowering power handling any differently than a ported box. But that could just mean I haven't heard it. winISD doesn't show it lowering overall power handling, but it has curves lower than tuning just like a ported box so they behave similarly in that fashion. So of course it depends on tuning as to where it will unload, just like a ported box.

[Smanleyman 15]

Hey cool I just got winISD running and modeled a ported box and a bandpass box at similar tunings, and depending on the bandpass tunings it's wayyyy more efficient just the highest output I could get was tuned at 41 and 42... The peak has a nasty rolloff above and below 41.3 hz or so, something like -24db from 41.3 to 41 hz, so I'm wondering if a 41 or 42 hz tone wont be that loud and I should try to get one of them to peak or will cabin gain even it all out?

Edited November 26, 2008 by fiq15pwnsnoobs

[KU40 173]

you'll definitely want a wider passband than .3 hz, haha. Aim for about 5 hz or so. That way you have a little room to play with as far as what frequencies will be loudest once you actually get the box inside the vehicle. Otherwise you'll be building box after box after box. And don't forget to look at the impedence graph. If your box is loudest at 42 hz but you have a huge spike in impedence up to 50 ohms at 42 hz, it's not going to be as loud as it could be.

Cabin gain will not even it all out. 24 db is way too much difference for cabin gain to help, and not to mention that power handling is probably lower at 41 hz in that box as well.

[fritosaregood 0]

And don't forget to look at the impedence graph. If your box is loudest at 42 hz but you have a huge spike in impedence up to 50 ohms at 42 hz, it's not going to be as loud as it could be.

where is the impedence graph on winisd

[KU40 173]

if you have the alpha version it's under the same tab as frequency response graph. Just above the graph.

[fritosaregood 0]

if you have the alpha version it's under the same tab as frequency response graph. Just above the graph.

oh i have the beta

[3stagevtec 2]

good info guys..

[Smanleyman 15]

hmm yea I have the beta so I dont know how to check my impedance graph, thanks for the help... I came up with a 40 and 44hz tuning though and the drop off isnt near as bad its louder than ported from 39-45 and 42 is 4db above 41 and 43 so somewhere in the middle should be very loud...

[KU40 173]

download the alpha. I don't know why, but the alpha has more options than the beta, and I think actually came out after the beta. Doesn't make much sense, I know.