6th order bandpass

[IMPALAMAN1]

THE BUILD PICS ARE HERE:

https://www.htguide.com/forum/showthread.php?t=18218&page=2

I had a chance to listen to it last night. It is paired with a nad2200. At first i was unimpressed with the results. I then put in some music with some low low sub.... and it came alive.... I put in "A MAN APART" with Vin D. cranked up the ol Kenwood 5.1 and let it roll. The box is boomy so i will have to dampen the inside. Ill need to drop the sub level some more as it over powers the fronts. I think i will try Starwars next.

Do any of you use a bandpass in your setups... if so what are you tuning to?

[Dennis H]

That's a beautiful box! I think your curve shows why bandpass boxes aren't very popular for home use. They boom at certain frequencies. The good news is, if you can't get the bandpass to work, it shouldn't be too hard to mount the driver outside and convert it to a conventional ported design. I'd expect it to sound much better that way.

[IMPALAMAN1]

YEA... I see the boom...... and can feel it... but it falls short in im thinking that i may try to fiddle with it a bit and see if i can get it to playe better.

my previous box was a sealed oz audio 300L 12. it did cool but wasnt enough. this is enough but doesnt blend so well... may have to figure out some more mid bass... hahaha

i am running the nht set up for the rest of the speakers... and it sounds good just need to tone down the boom a bit.

[Mark Seaton]

Bandpasses don't have to perform like the response shown. They can be very smooth with the right proportions. One major trick is in keeping the port well behaved while also getting the desired volumes of each chamber for smooth response. There are some cool benefits, but there are also more potential pitfalls.

[Patrick Bateman]

That's a beautiful box! I think your curve shows why bandpass boxes aren't very popular for home use. They boom at certain frequencies. The good news is, if you can't get the bandpass to work, it shouldn't be too hard to mount the driver outside and convert it to a conventional ported design. I'd expect it to sound much better that way.

There's one big problem with bandpass boxes -

They almost NEVER work like the models predict. I cannot STRESS how important it is to measure the impedance curve on a bandpass box. It is literally IMPOSSIBLE to get bandpass to sound good unless you tune the vents VERY carefully.

A well done bandpass can sound fantastic, as long as they're tuned properly.

Just off the top of my head, here are some things that can screw up your tuning:
- the box leaks
- the woofer needs to be BOLTED to the box. The tiniest leak, or a flimsy mounting will screw up your vent.
- If the wall resonates in the SMALLEST amount, it will screw up your tuning.

Seriously, go buy a Dayton Woofer Tester II and check your tuning before you condemn the whole family.

[IMPALAMAN1]

Not a bad idea. Ill have to check that out.

[Patrick Bateman]

Not a bad idea. Ill have to check that out.

Right now I'm building a single reflex bandpass, and for the test box, I assembled it with glue. When I measured it, the results S U C K E D. It turned out it was leaking. I wound up screwing the driver into the baffle, and THEN gluing the baffle.

Here's the kicker though; I'm using a driver that's 1.5" across!

So if this TINY little driver is moving enough air to cause tuning problems, can you IMAGINE what kind of randomness can occur with TWO ports and a driver that's easily 20x larger?

[IMPALAMAN1]

PICS AND SPECS? that sounds like a interesting project. years ago i had the oppertunity to build a desing for a pair of 6.5"s in a compoundloaded single bandpass. the results were quite impressive. ill have to see if i can dig up the specs for it.

[Patrick Bateman]

PICS AND SPECS? that sounds like a interesting project. years ago i had the oppertunity to build a desing for a pair of 6.5"s in a compoundloaded single bandpass. the results were quite impressive. ill have to see if i can dig up the specs for it.

The "bandpass" is for the midrange drivers in the unity that I'm building. This is going into my Honda Accord. Here's the URL for the construction thread; there are some pics of the measurements and stuff on there.

http://www.audiogroupforum.com/csforum/showthread.php?t=62789

[IMPALAMAN1]

im a member of that forum aswell and have been following the post. i dig the idea.