DiyMobileAudio.com Car Stereo Forum banner

How does isobaric mounting affect distortion?

  • Reduces it

    Votes: 20 44.4%
  • Increases it

    Votes: 5 11.1%
  • Don't know

    Votes: 15 33.3%
  • Clamshell/mag2mag decreases it

    Votes: 8 17.8%
  • Tunnel/cone2mag decreases it

    Votes: 2 4.4%
  • Clamshell/mag2mag increases it

    Votes: 0 0.0%
  • Tunnel/cone2mag increases it

    Votes: 0 0.0%

  • Total voters
    45
21 - 24 of 24 Posts

·
Registered
Joined
·
1,112 Posts
I have been modeling a lot of 6th order bandpass setups lately and have thought about isobaric drivers as a means to reduce the box size. I have been able to model out some flat-responding low-group-delaying boxes that are 1/4 the overall chamber volume of both sides when the drivers are paired isobaric compared to not. The port lengths seem to want to increase 4x in length, though, for the same cross sectional area.

Here is one I did with some JL 10w0's. 4 subs in 7 cubic feet before port vs. 2 isobaric pairs in 2 cubic feet before port. What's interesting is that 4 isobaric pairs in 4 cubic feet before port models identical to 2 pairs in 2 cubic feet (duh), so you could theoretically have the same output and response as 4 non-paired subs in a little more than half the space yet needing twice the power. But.. we're talking about 150wRMS per speaker here so it wouldn't shatter your bank account or your alternator!


 

Attachments

·
Registered
Joined
·
555 Posts
it cancels out odd-order non-linearities,it is also extremely tight and accurate,tiny box,yes porting can be tricky,(the ports do get long and the enclosures are usually small),they are not meant for spl. i did a setup in a crx probably (showing my age)almost twenty years ago,it used 8 jl 10w5 in a v-shaped enclosure,ported,in the hatch area he could still use the front and top cargo cover,this was running off a single ppi 2300am running two ohm stereo,that thing would play the low low bass notes so well,i mean like 30-60 hz, not 60 hz and up.real low bass.i think he actually had to replace the seals in the hatch.loud car.but amazingly accurate,especially if you like bass guitar and kick drum,wow .
 

·
Registered
Joined
·
563 Posts
I ran an isopair, face to face, back in 92-93 for about 2yrs. I was trying to get the smallest enclosure possible in the back of my beretta. It turned out well and would do it again if space was an issue an i had an exact extra driver to burn. However, i doubt i would go out of my way to replicate it.
 

·
Registered
Joined
·
551 Posts
I ran 4 MTX RT2154's in a 3 chamber BP4 isobaric box in a 1983 Mercury Grand Marquis. I had an Autotek 7300BTS running 1 ohm bridged. That thing talked to whales. It had 4 ports corner loading the rear of the trunk. Tuning was 60 hz. When I donated the car in 2002 after the head gasket blew, we had a garage sale that same day. The box was the 1st thing that sold. I miss that car!!!
 

Attachments

21 - 24 of 24 Posts
Top