Luke

Has anyone changed their Sub box from a sealed to a ported enclosure?? And what did you think. I am thinking(!!) about re-housing my JL8W6's.

nom

Depends on the sub, but loses 'attack' & depth, gains efficiency (although can't handle as much power). Works well for smaller subs with not enough amplification.
Worth having a bash once all the calculations are done, though, if you've got the time

chiark

Better still, JL Audio had a mini that could convert from sealed to ported at the flick of a switch - see their website for more!

nick.

ianc

My basic rule of thumb is this....

Build a box as large as you can get away with, bearing in mind the missus' dislike of having shopping on her knee and a pushchair on the back seat next to the kids.

Mount subs amps etc, fit it into the car, see how it sounds...

If it's deep enough and punchy enough then great, well done, leave well alone.

If not, port it. IMHO sealed boxes are far better but you need a decent capacity (ie if it doesn't take two of you to carry it, then it ain't big enough), subs can handle more power, and looked after better by the air pressure cushioning the cones movement. A smaller ported box can be as punchy but will tend to struggle with heavy bass "tones" rather than "beats", ie bass guitar etc.

If you favour steps \ chart dance music then ported should be fine.

If you favour more guitar led stuff then keep it sealed or get a bigger box.

Just my euro's worth....

IC

chiark

and this is the link to the mini.

chiark

and, as a rule of thumb, I have to agree with IanC. I did use ported boxes before and boy they are loud at the frequency that you tune them to, but I prefer the sound of sealed. Plus be verrrry careful working out the port as your driver is effectively working without the air suspension below the frequency of the port!

Luke

Ok sealed it is. Would love to make custom fibreglass job... How the hell do they get the Volume correct??? Do you measure dry sand and pour it in??

That mini in the JL AUDIO web site!!!! I like the bit about getting the sound stage correct. Other then building door builds to raise the speakers about 6.inches higher.What other tricks can be used??

audio g man

Luke me old mukka.......

If you measure the volume of a box with dry sand you'd have to build it first and if it's wrong, you'd have to build another one and what if thats wrong too?

For box volume calculations, check out "volume calculators" and "woofer enclosures" at "www.the12volt.com"

http://www.the12volt.com/caraudio/boxcalcs.asp
http://www.the12volt.com/caraudio/boxes.asp

As far as the sound stage goes, the factory locations in the top of the doors aren't great. They almost face each other and the're a bit 2 close to your ears. In my old BMW E30 i fitted the tweeters down low in the footwells in the factory speaker locations with the 17cm mid-bass drivers in the bottom front of the doors. The tweeters were about as far from the front seat passengers ears as possible and mounted on axis. (right tweeter pointing at passengers right ear and left tweeter pointing the drivers left ear) It was very good but not quite there so i wired the left tweeter out of phase and.........perfect. Wiring the left tweeter out of phase lifted the soundstage a little.
There was no rear speakers, just a sub.

I've now got a late Escort and the speaker locations are in the same place as the impreza tweeter positions so i tried the above but it just wasn't doing it 4 me so they are now on top of the dash reflecting off the windscreen which is working quite well.
Experiment using blue tak to stick the tweeters in different positions.
Rear full range speakers can spoil the front sound stage so don't have them too loud.
Check your previous post about speakers and gain controls and don't forget to have a look at www.the12volt.com.
G.

Luke

AGM

Cheers. Cant move the tweeters!! but they can swivel!!. Like the idea of swapping the left tweeter phase over. No rear speakers!! like the sound from front only.

So moving speakers higher wont help??? what else could I try??/

The car is a Legacy. Speakers are down the bottom



[Edited by Luke - 2/14/2002 8:17:03 PM]

audio g man

What speakers do you have?

Luke

AGM

Ok here is the complete system!!

Rockford Fosgate cd head unit. Not the new "Horrid ones"!!
Nakamichi Sub active control with high pass feeding front amp.
Genesis DM 200 dual mono amp driving 2 x JL audio 8w6's subs .Crossed over at 50 or 70 HZ
Soundstream SA 164. 4 x 50 watts,bridged to run DLS pro series 6.5inch Coax speakers. These have silk tweeters mounted in center that can be tilted. I have these crossed over at 50Hz from the high pass output from the Nakamichi.
I also have a Nakamichi Active for the fronts. But am led to believe the passives will be better???

Have looked today at changing phase on left tweeter. Does not look easy???

All help needed!!


Luke
I am using the passive crossovers that came with them.