Question about rms wattage for subs

 

Silver Member
Username: Davids2004

Houston, TX USA

Post Number: 463
Registered: Jun-04
I have a 2 channel amp that puts out 400 rms bridged at 4 ohms. That will give me 200 rms per sub. I have some HE2 subs that are 300 rms per sub. I have them in a sealed box right now and they just arent loud enough. Would putting them in a ported box help me out any or would it be a waste of time. Thanks.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1020
Registered: May-04
Yeah, it will allow them to have more excursion since the box has less control over the cone, plus you get much more output since you'd create the equivalent surface area of 4 subs.
 

Silver Member
Username: Davids2004

Houston, TX USA

Post Number: 464
Registered: Jun-04
Jonathan,

How will it allow you to create the equivalent of 4 subs? Just curious
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1025
Registered: May-04
Because the port allows both sides of the subs to be used, doubling the surface area, just as you would be using 4 sealed subs.
 

Silver Member
Username: Davids2004

Houston, TX USA

Post Number: 465
Registered: Jun-04
Jonathan,

So you think with the 200 rms on a 300 rms in a ported box I will be ok.

Thanks in advance.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1026
Registered: May-04
Yeah, it will be fine. No worse than the sealed you had it in. As far as the tuning frequency, try to use a subsonic filter or Harrison Labs F-mods below that if possible to avoid overexcursion of the driver.
 

Silver Member
Username: Davids2004

Houston, TX USA

Post Number: 466
Registered: Jun-04
Well do you think it will get louder then the sealed box or im just pretty much stuck.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1029
Registered: May-04
Oh yeah, it should be a lot louder, probably 5-6 dbs.
 

Silver Member
Username: Davids2004

Houston, TX USA

Post Number: 467
Registered: Jun-04
Because I know with a ported box with about 50% of the rms wattage it will usually get louder. I figured since im only using about 60-70% of the rms I would be fine without a subsonic filter IMO.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1033
Registered: May-04
Yeah, it just depends on the tuning frequency. A ported box has a 24db/oct rolloff below the tuned frequency, so if you tune higher, the box will have a steep rolloff at the really low frequencies and the subs won't have as much excursion at that point.
 

Silver Member
Username: Davids2004

Houston, TX USA

Post Number: 469
Registered: Jun-04
Since I didnt have a ss filter I was gonna buy a probox superbass box tuned at 45 hz.
 

Gold Member
Username: Jonathan_f

GA USA

Post Number: 1035
Registered: May-04
Kind of a high tuning frequency, but with that box it should be fine w/o a SS filter.
 

Silver Member
Username: Davids2004

Houston, TX USA

Post Number: 470
Registered: Jun-04
Yea I know its high but with vehicle acoustics it could come down some. My point with the SS filter tuning it higher I should be fine.
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