quality amp with 20-25 hz subsonic filter?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=101711
Printed Date: April 27, 2024 at 10:40 PM
Topic: quality amp with 20-25 hz subsonic filter?
Posted By: kamberkash
Subject: quality amp with 20-25 hz subsonic filter?
Date Posted: January 30, 2008 at 11:58 AM
Anyone know of a good *quality* amp that has a 20-25 hz subsonic filter on it? Anyone that has experience with the alpine PDX series amps please chime in, i cant tell if they even have a subsonic filer (and i do want to try these out BAD)
i just couldnt convince myself to spend well over 700 dollars on a sub so i made my mind up and i am going to *try* to get 2 shiva-x subs with my tax return. a guy from diycable.com suggest 3.5^3 enclosure, with at least a 50^2 in port tuned to 20 hz. at 3.5 cu. ft i dont think i will be able to fit 2 in there, thats like 7 cubic feet  but i will try!
Replies:
Posted By: sedate
Date Posted: January 30, 2008 at 1:19 PM
I was seriously considering these woofers, but I just don't have the space and probably not the power. Looking at these woofers, they really do need a massive amplifier - what is your budget here? kamberkash wrote:
Anyone know of a good *quality* amp that has a 20-25 hz subsonic filter on it?
While I'm a huge fan of JL's 'slash' amplifiers - here I'd recommend a JL1000/1 - fully variable subsonic filter on that beast - but I do think that 1000watt PDX would be a great choice - not shure about the subsonic filter tho .. ------------- "I'm finished!" - Daniel Plainview
Posted By: kamberkash
Date Posted: January 30, 2008 at 1:52 PM
with the money i will be saving (because these woofers are CHEAP!) i can afford to go with something thats in the range of $500-$1000. if im not mistaking the 1000/1 is like $1100, right? do you really think this woofer could handle 1000 watts rms? pmax is 600 watts, so i was thinking of goin with the pdx1.600 if it has a subsonic filter...
im open to all suggestions on amps, as long as its a *quality* amp, i dont want some sony, or audiobomb peice-o-dudu.
Posted By: sedate
Date Posted: January 30, 2008 at 2:55 PM
kamberkash wrote:
if im not mistaking the 1000/1 is like $1100, right? do you really think this woofer could handle 1000 watts rms
Street price on that amp should be, at most, $850. I can get it from a bricks-and-mortar dealer down the road for $725, if I pay in cash. Don't ever pay MSRP for stereo gear - this is just silly. Don't get me wrong - those Shiva's are priced right, but they have a totally different distribution model than JL gear does. Anyway - I think you said you wanted a PAIR of Shiva's - so they'd get a solid 500watts a piece, not 1000. I think the JL1000/1 is a great match to those subs - particularly given the low effiency of that sub - you want a real strong amp backing those - again I really wanted a pair but the low efficiency and large box requirements have convinced me to look elsewhere. I imagine you could get that PDX amp a bit cheaper than the JL1000, even if you find a good deal. I seriously doubt a PDX1.600 is going to power a PAIR of Shiva's however - I really wouldn't bother with less than than the PDX1.1000 ... ------------- "I'm finished!" - Daniel Plainview
Posted By: kamberkash
Date Posted: January 30, 2008 at 3:06 PM
yeah, i will get a pair IF i can fit a box thats over 7 cu ft in my trunk! i havent took a second look yet and actually measured anything yet so i will find out soon.
Posted By: sedate
Date Posted: January 30, 2008 at 6:05 PM
What kinda vehicle? ------------- "I'm finished!" - Daniel Plainview
Posted By: kamberkash
Date Posted: January 30, 2008 at 6:43 PM
2000 Pontiac Bonneville. its got a massive trunk area, but i do want to use some of it(for things other than a subwoofer box). i need space for my amps and such.
Posted By: sedate
Date Posted: January 30, 2008 at 7:00 PM
Yea those things are cavernous. Still - 7cft is freaking enormous and even if you could fit that external volume into the trunk opening let alone whether or not the internal volume of the trunk would hold the box. And you car is going to be riding *low* in back ... hehe... I think perhaps, if you are in love with these Shiva's, you should get a single one - I'd port the enclosure @ 30hz or so.- you'll still have an external volume of some 3.5cft - this is a huge box. That PDX1.600 is a good match for that - but the efficiency is so low on those subs I really wouldn't go with a sealed enclosure - I'd think it'd need huge power numbers to reach higher excursion numbers. These are nice woofers, but the power requirements and volume requirements give me reservations for these to be used in a car. They just look like better home subs to me. ------------- "I'm finished!" - Daniel Plainview
Posted By: kamberkash
Date Posted: January 30, 2008 at 9:02 PM
one side note about it riding low in the back - it has an air ride system on it that address that exact issue. if something is weighing it down in the trunk, the car turns on the air pump and lifts it back up.cool huh?
anyway, i just got finished taking a look at the trunk, and a 7 cu ft + box just aint happenin. granted, it will fit, but i wont have any space left. so i think im going with just one of these. Now after taking that into consideration, i now have even more money for some amps!
so does anyone know if the pdx has a subsonic filter?
Posted By: audioman2007
Date Posted: February 12, 2008 at 4:20 PM
What exactly is a sub sonic filter anyways? When are they used? I have one on my amp but dont know what it does
Posted By: greenbroncoguy
Date Posted: February 12, 2008 at 4:44 PM
audioman2007 wrote:
What exactly is a sub sonic filter anyways? When are they used? I have one on my amp but dont know what it does
It's basically just a high pass filter that lets you select which frequencies above a certain point you want to allow. This will keep your driver from over-exurting itself on frequencies lower han it can effectively reproduce. So, for your sub, you could set your sub-sonic filter to 20hz or so and it would start cutting frequencies out from 20hz on down - this can help emmensly in a vented box where, below the tuning frequency of the box the sub mounted in it will effectively become "unloaded" and can become damaged by over excursion. -Matt
Posted By: audioman2007
Date Posted: February 12, 2008 at 4:52 PM
Ok So what you are saying is If I have my subs (which are 2 12" earthquake dbX sc) in a ported box which I will be making this friday, these subs are tuned to 35HZ therefore I will make the box tuned to 35. You are saying I would then set my sub sonic filter to 35HZ so any frequencies at and under 35HZ will be cut off?
Posted By: greenbroncoguy
Date Posted: February 12, 2008 at 5:52 PM
What do you mean that your "subs are tuned to 35hz"? Are you trying to say that the FS of your subs is 35hz? Because I don't think it is., and subs aren't "tuned" to any specific frequency that I know of... But the rest of what you posted is correct - if you tuned the box to 35hz, then I would set your subsonic filter to about 28-30hz, maybe even 25hz depending on how much power you're going to push them with. My box with my 2 DBX 12's is tuned to 30hz, and I have subs bandpassed from 20-50hz - it goes loooooww and stays clean... -Matt
Posted By: audioman2007
Date Posted: February 12, 2008 at 8:09 PM
I meant the FS of the subs are 35Hz. I looked at the new dbX and found 35, and everyone has been saying the new are the same as the old FS wise. Anyways a friend had the same sub as I do except his was a dual coil. I bought the sub and the box it was in for $20. The box is a ported box measuring 5/8 thick 14" wide 19" deep 16 1/2 high outside measurements. The port then is 3" high 12 3/4 wide 16" deep. Could someone see what the box would be tuned to? Thank you. Oh another thing, is it recommended to have a subsonic filter for subs in a vented box?
Posted By: Alpine Guy
Date Posted: February 12, 2008 at 8:17 PM
Yes, the PDX does have a subsonic at 15hz or 30hz.
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2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.
Posted By: haemphyst
Date Posted: February 12, 2008 at 8:38 PM
And I can speak from experience... The PDX1.1000 is a POWERHOUSE!!! I love mine.
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
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