Fordmods Logo

Will underpowering subs do them damage? 

 

Page 3 of 3 [ 39 posts ] Go to page Previous  1, 2, 3

 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Mon Feb 14, 2011 7:38 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

You've got to take into account cabin gain which in larger cars like Falcons and commos is usualy mid-high 50's. Build a box to match that, and you can get some impressive - if short lived results.

I got *cough* had a pair of 6x9's pushing 138dB - once. Problem being when cabin gain and box porting match, you unload the drivers, and they tend to tear themselves apart (unless they've got a really stiff suspension).

Image

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Tue Feb 15, 2011 9:13 pm 
Getting Side Ways
Offline

Age: 26

Posts: 1109

Joined: 4th Sep 2009

Ride: 92 EB s

Location: DORRIGO
NSW, Australia

No worries sam. Reckon if you got a 2nd mono and 2 nice big slot port boxs(gotta love falcon boot space) plus the battery you should pull 140+.

Did you Realy pull 138 with those 6X9s?
Run off a amp I presume.
Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Tue Feb 15, 2011 9:21 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

87SIlude wrote:
Did you Realy pull 138 with those 6X9s?
Run off a amp I presume.


Yep, and Yep (~800W worth)

As said though they didn't survive.

Box design plays a HUGE part in getting loud if that's what you want. Also important for good sound quality.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Tue Feb 15, 2011 10:15 pm 
Getting Side Ways
Offline

Age: 26

Posts: 1109

Joined: 4th Sep 2009

Ride: 92 EB s

Location: DORRIGO
NSW, Australia

How was that 2 6x9 box made?
Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Tue Feb 15, 2011 11:01 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

87SIlude wrote:
How was that 2 6x9 box made?


???

Like any other box, six sides, some holes, glue and screw.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Wed Feb 16, 2011 9:25 am 
Getting Side Ways
Offline

Age: 26

Posts: 1109

Joined: 4th Sep 2009

Ride: 92 EB s

Location: DORRIGO
NSW, Australia

Yea I was thinking there would be some internal panels or something.
Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Wed Feb 16, 2011 11:03 am 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

87SIlude wrote:
Yea I was thinking there would be some internal panels or something.


Ah, box design.

That one, no just a ported box.

I made another one, 6th order band pass* with the speakers internally in an isobaric config. simulation showed they'd get 2dB louder or so, but speakers died so never tested.

*effectively two ported boxes joined in the middle, speakers on the middle baffle, each side tuned for a different frequency, the speakers play their loudest between those two freqs. I'd had it tuned for 54Hz one side and 56Hz the other - completely useless for music, but loud at 55Hz.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Wed Feb 16, 2011 3:26 pm 
Getting Side Ways
Offline

Age: 26

Posts: 1109

Joined: 4th Sep 2009

Ride: 92 EB s

Location: DORRIGO
NSW, Australia

That's the one.
How did you manage 138 with that setup as just a ported box.
Top
 Profile  
 
 
 Post subject: Re: Will underpowering subs do them damage?
Posted: Wed Feb 16, 2011 4:10 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

87SIlude wrote:
That's the one.
How did you manage 138 with that setup as just a ported box.


I started by carefully measuring the TS parameters of each speaker (not relying on the 'on the box' specs, not the DD publish specs anyway - bad DD).

Again carefully measured the frequency of most cabin gain in the car. Stepping through a custom made CD of individual Hz tones, with a dB meter (wasn't a termlab as I don't have access to one normally).

Then design the box to suit the speakers and the tuning freq I wanted. Fed it bulk power, @ 2ohm's the amp specs say it'll do 800WRMS, so two 4 ohm speakers in parallel = 800W. No wonder they didn't last - they're rated for 50W each, and the port tune meant they'd be largely unloaded.

Starting at very low volume (power), ran through the tone CD again, to confirm the cabin and port gain were working together. Then figuring I'd only get one go at it, hooked up the termlab, cranked up the volume and played the one burp.

Additionally, being a "ghetto 6x9 comp" (an little for fun comp a few of us ran as part of a MEASQ and dBDrag event) the only rules were a control set of speakers the DD 6x9's and any box had to be below the window line and behind the B pillar. So it got sat on the rear seat, so didn't have to work from a boot.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 3 of 3  [ 39 posts ]  Go to page Previous  1, 2, 3

Who is online

Users browsing this forum: No registered users and 11 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

 

 

It is currently Tue Dec 12, 2017 5:54 pm All times are UTC + 11 hours

 

 

(c)2014 Total Web Solutions Australia - Australian Web Hosting and Domain Names