Subsonic filter with sealed box?

[bestntx 10+ year member]

I'm currently running 2 tc1000 12's in a 2.2^3 box. I'm pushing them with an alpine mrd m605 600x1 amp. I feel like they could get lower but it almost seems as they are bottoming out. I'm running 200 less watts per sub than the RMS rating, I can't imagine that they can't handle the 600 watts that i'm feeding them. So my question is; is it ok to adjust my subsonic filter to tune the subs? I've got the crossover set at 50hz through my head unit currently.

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[newusername 10+ year member]

First, let's clarify a bit:

Subsonic - Slower than the speed of sound

Infrasonic - lower in frequency than the human ear is capable of hearing (ie. below 20 Hz)

I don't have the time to model this for you at the moment. However, you can use the driver's Thiele/Small parameters and plug them into a program like UniBox or WinISD (Google them if necessary). You can model the excursion vs. frequency for a given amount of input power. If the driver appears to approach its linear limits (ie. approaches Xmax) in the enclosure you're using, set the infrasonic filter at the frequency where this begins.

I can tell you almost certainly that you won't need to with the setup you're using.

 

[TeoTorriatte 10+ year member]

^^^What Neil said...^^^

I really doubt you are bottoming out with 300W going to each one... clipping, however, can sometimes make you think you are bottoming out... are your sub amp gains set so that the fronts and sub balance, or are they just set with a dmm for maximum output (regardless of front stage volume)?

 

[mtlhead 10+ year member]

I'm currently running 2 tc1000 12's in a 2.2^3 box. I'm pushing them with an alpine mrd m605 600x1 amp. I feel like they could get lower but it almost seems as they are bottoming out. I'm running 200 less watts per sub than the RMS rating, I can't imagine that they can't handle the 600 watts that i'm feeding them. So my question is; is it ok to adjust my subsonic filter to tune the subs? I've got the crossover set at 50hz through my head unit currently.

lol, your subs can handle 600 watts. Mine are taking ~1kw apiece

 

[bestntx 10+ year member]

Thanks for the technical explanation... and I feel my gains are set accordingly with the front. So you guys think that my subs could handle a substantially larger amount of power?

 

[dragnix 5,000+ posts]

bottoming out in a sealed box?

 

[bestntx 10+ year member]

bottoming out in a sealed box?

Yes, this is why im kind of stumped

 

[Electrodynamic 10+ year member]

First, let's clarify a bit:
Subsonic - Slower than the speed of sound

Infrasonic - lower in frequency than the human ear is capable of hearing (ie. below 20 Hz)

Neil,

I think you're swimming up stream with this one bud. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif It's going to take a lot of your life to convince the amplifier manufacturers and audio industry in general to start referring to subsonic as infrasonic. I can see it now, "THIS JUST IN! Audio amplifier manufacturers around the world are recalling all of their amplifiers to replace the text "subsonic filter" with "infrasonic filter". //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Besides, it's more fun to say subsonic. Just like DeeBeeeez!!! //content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif

 

[helotaxi 5,000+ posts]

It's not hard to bottom out some subs in a sealed box. I find it amazing that people think that putting a sub in a sealed box makes it immune to bottoming out. With the same power applied, a sub will attempt to move farther at lower freqs. This is most true in a sealed box where the inertia of the air in the port to greatly limit the excursion around tuning. The air spring provided by a sealed box can only do so much.