G'day Guys,

A quick question.

I now have a bandpass enclosure for my 2x12" subs. Am I better off using the HPF (High Pass Freq) on the amp, as the LPF may be a over kill with the bandpass enclosure being designed for low freq as I understand that you can still damage your subs in a bandpass enclosure even though there is less coil movement? (with out going into to much technical detail)

Thanks Guys!

Why would you ever use a highpass filter on a sub ???? Subs are designed for LOW frequencies.

You could have a high pass set at 100hz or so, but you'd still need a low pass. This is a bandpass crossover. I wouldn't bother.

I can do all this from my HU.

Good point! so would I be better off just setting the LPF at a higher level? (please excuse me, I'm still learning)

running the high pass on a sub can also damage the sub

Thanks guys! I will just lean off the low frequencies on the LPF, so that I'm not getting to much low droaning bass, coming from the bandpass box.

set the x over point on about 180hz, the gain should match the output of the HU eg 5v. use the boost control to adjust the level of the sub.

Will do! thanks guys!

A high pass filter filters out low frequency's below a set level e.g. 100htz, this is what shou8ld be used on your full range drivers (ie splits or co-axials) to prevent them from having to reproduce low frequency's that require a large amount of air movement (and excursion). Having a HPF on them will allow the speakers in the car to play louder, more safely.

A Low Pass filter, filters OUT higher frequency's and is designed for sub's (or in some cases midbass drivers) which are not able to reproduce the fine detail of higher frequency's.

A bandpass box is just the same as any other enslosure in that it provides a certain response for your subs (allbeit a different response from sealed, ported or AP designs). It does not have any filter in it although it does have a natural roll off because of it's design.

Question Answered: You should use a low pass filter from around 80 - 100htz depending on what your intergrating them with in the car (i.e. 4", 6" or 8"inch mids etc...)

I trust that the bandpass enclosure you have is specifically designed for those drivers as it can severly affect the output of subs if they are in the wrong bandpass enclosure. Sealed boxes are the most forgiving, ported must be made right or your sub will become unloaded at certain frequency's easily destroyed. BUT bandpass are the most compicated and must be exactly right for the sub to get good response.

I hate a mate with 2 x 12's in a pre-fab bandpass box. i made a ported enclosure specifically for his speaker and ran a single 12' with the same amp and got a much better result (both clarity and output) than having 2 x 12's + more boot space.

EFMumFord: Just a quick question, why did u get a bandpass box anyway? usually these are designed for very specific installations where space and frequency response aren't an issue.

Thank you for your very helpful information!!!! The box is a pre-fab bandpass, though after my local car audio shop put in the information for a custom made bandpass box, it turn out that the pre-fab, was most suited to my subs. I installed the subs into the box and hooked it up to the amp to save some money. I am very happy with the end result

Thanks again!

No problem thats good to hear.

The pre-fab ones are made to suit a variety of wooffers i'm glad your suit an enclosure such as that. I just ask people to check because not all woffers sound good in them.

I was after the extra depth in bass, that I was'nt achieving from my other enclosures, no matter how the amp was set in the frequencies. I'm very happy with the end result, as it is just what i wanted.

Isn't it funny how at the begining, I was happy with just a single sub and a amp with coaxial speakers, just to improve on the standard factory tape deck. Then I moved on to a extra sub and a extra amp then some splits for the front, only a month a go. Only yesterday I went back to the audio shop and spent $399 on a set of pioneer splits ( think they are called the bullet splits) to improve on the front staging of sound. It's like a virus (bug) that you can't get rid of. You just seem to want more and more of the audio medicine to get rid of the bug LOL

Certainly is a bug, i have a systemt hat most would be pretty happy with and i can see HEAPS of room for improvement.

When i startde i had 50rms per side to my fronts and thought it was a huge improvement over the headunit (which i guess it was) now i have 350rms per side and get the amps up to clipping before the speakers reach their limit, would love 600rms per side.

Omg!!! 350 rms per side, how's your ears? lol. What set up are you running?

Actually come to think of it it's 400rms per side.

50rms to Morel Supremo tweeters - active
350rms per side (Phoenix Gold QX2350 bridged) to focal utopia 4" midrange and 6.5" midbass (in sealed fibreglass enclosures)

Then approx 1000rms to DVC 15" sub from an Earthquake digital amp