sq box build

[Moble Enclosurs 10+ year member]

if you do not have time alignment on your sub channel passive radiators will not work. also with these low xmax subs you can get away with much less port area. Lastly are you sure 29hz will play flat in car? that sounds way low with out a separate higher tuned sub woofer

This is true. The vehicle will determine more of the LF response than the enclosure will. This can be calculated for, optimally, if desired and I would not recommend a design without that information. This is why we all have said 29Hz seems low. But again, this is always your decision, not ours.

As far as passive radiators, this is true, the delay will be a factor, but unlike ported designs, the resonances within the enclosure are less of an issue for output, due to compliance. So, you will not have major phasing issues like you do with a conventional design, but not to say it is not an issue, by all means. But other factors of a PR make resonances less of an issue in such a small space. This would be more of a concern in a larger acoustical area than a vehicle. Either way, it is definitely something to look at, as all variables are. SO, that being said, great point.

 

[wenn_du_weinst 10+ year member]

It's usually over looked so figured I'd bring it up

 

[Bumpin' Goalie 10+ year member]

I'm guessing that software only showing the roll off as frequency decreases is being used by the majority of folks here. Unfortunately, a combination of that and improper abilities to properly reproduce 60-120hz (without dragging the imaging to the rear) can lead to some problems.

That being said, it is always easier to EQ something down than up. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif I am aware of the enclosures used and loved over on DIYMA for these woofers. However, vehicle-dependent gains and losses are not always calculated for.

But to be fair, these issues and some of the more advanced sciences that come along with properly utilizing PR's are not too many people's priorities. What may sound superb to some may sound sub-par to others. Such is the perception aspect of car audio.

 

[06goat 10+ year member]

You could run slot ported i imagine.

To much port noise for a SQ build

 

[Moble Enclosurs 10+ year member]

To much port noise for a SQ build

The type of port is not a factor of port noise. You can have port noise in any port of insignificant size. Being a slot port is not a factor in "noise", but the SIZE of the slot port will be the factor, along with the ratio of length and width. Is that kinda what you mean?