I need a subsonic filter

2661 Views 21 Replies 8 Participants Last post by NOTORIOUS97200, Apr 30, 2009

NOTORIOUS97200

Discussion Starter · Apr 28, 2009

Hi everybody,
I have a 15" sub (SSA Icon) in a 4 cu ft vented enclosure, powered by a JL Audio A1800D @ 4 ohms(650w rms).
This amp does not have any subsonic filter.

My hu is a Pioneer p88rsII, and I use the 3 rca's, 2 for the front to a Boston GT42 amp, and the sub out .

What can I do, what brand of processor to buy to have a SSF ?
I nedd something that can work well after the sub out of the hu and before the amp.
I thought of an Audiocontrol Epicenter, but I think it is not the good choice because it can't work off the head unit sub out.

What do you think?
Give me some advices, PLEASE !!!

1 - 20 of 22 Posts

dawgdan

· #2 · Apr 28, 2009

Crossovers

See the second item down and choose between 20 Hz or 30 Hz (what I'd go with). Very cheap and very easy way to accomplish your goal.

89grand

· #3 · Apr 28, 2009

We talked about this before. Why do you think you need one?

VP Electricity

· #4 · Apr 28, 2009

Or at least to find out if it helps, and then you can get a good one...

hifonics used to sell a in-and-out active subsonic at 30 0r 35 hz. helped sometimes, didn't help other times, but plugging it in and finding out was worth a lot more than talking about it

89grand

· #5 · Apr 28, 2009

I've ran ported enclosure without one and never felt the need for one.

chad

· #6 · Apr 28, 2009

89grand said:
We talked about this before. Why do you think you need one?

89grand said:
I've ran ported enclosure without one and never felt the need for one.

yeah and yeah.

Where is the OP's enclosure tuned? (what frequency not what side of the box)

NOTORIOUS97200

Discussion Starter · #7 · Apr 28, 2009

It should be tuned around 30-33 Hz, according to what they told me here (don't remember who!). 4 cu ft with a 6ft round port of 14.10" long. Hope this will be good!

89grand : you told me I don't really need one, but everybody say it can be usefull !!
So, I just want to try by myself if it is not too expensive.

I try to give my friends some of your advices, in order to sell them all they need!!!
But it can't be so bad to try and test by myself, when I can.

NOTORIOUS97200

Discussion Starter · #8 · Apr 28, 2009

I have to say one more thing:
two of my friends have the same Kicker sub(S15L74) as I had, but I can clearly notice that they sound much "better" than mine. I mean they were way more powerful with the same power from the amp. They both use an active filter(or crossover ?). When this filter is disconnected, their bass is not so different from mine. We all ran these subs in big sealed enclosures.
That is, partly, why I want to test something, if I can afford it !

89grand : I respect what you said, and I believe you. I have ran ported enclosures without subsonic filters too, without any problem.

89grand

· #9 · Apr 28, 2009

My point is, if you tune the box to around 28-32hz you will have no need for the filter. You haven't made the enclosure yet so if you you tune it right, the filter will be completely unnecessary.

I'm just trying to save you money and time.

[email protected]

· #10 · Apr 28, 2009

It helps with the woofer unloading under tuning, which not much music has content that low, but it wont hurt, I would run one, but also note they are usually 24db not 12, so if all you can get is 12db I prob wouldnt mess with it

NOTORIOUS97200

Discussion Starter · #11 · Apr 28, 2009

I will have my enclosure ready by tomorrow afternoon, so It will have to play without any ssf, for sure!
I am not at all a pro in box builiding, and my friend maybe be good at wood cutting, but certainly not in fine box tuning : he always tune by ears !

How can I be sure about the tuning ? even though I just did what they told me here?

In my little country, I am quite sure that everybody tune their enclosure by ears. How can I do it seriously? What do I need, to do it right ?

[email protected]

· #12 · Apr 28, 2009

NOTORIOUS97200 said:
I will have my enclosure ready by tomorrow afternoon, so It will have to play without any ssf, for sure!
I am not at all a pro in box builiding, and my friend maybe be good at wood cutting, but certainly not in fine box tuning : he always tune by ears !

How can I be sure about the tuning ? even though I just did what they told me here?

In my little country, I am quite sure that everybody tune their enclosure by ears. How can I do it seriously? What do I need, to do it right ?

You just need to get it close, your not gonna be able to tell acouple hertz in tuning

89grand

· #13 · Apr 28, 2009

NOTORIOUS97200 said:
I will have my enclosure ready by tomorrow afternoon, so It will have to play without any ssf, for sure!
I am not at all a pro in box builiding, and my friend maybe be good at wood cutting, but certainly not in fine box tuning : he always tune by ears !

How can I be sure about the tuning ? even though I just did what they told me here?

In my little country, I am quite sure that everybody tune their enclosure by ears. How can I do it seriously? What do I need, to do it right ?

Did you model it in a box building program like winISD?

That'll tell you how big in diameter and how long to make the port for whatever tuning frequency you choose.

Boostedrex

· #14 · Apr 28, 2009

89grand said:
My point is, if you tune the box to around 28-32hz you will have no need for the filter. You haven't made the enclosure yet so if you you tune it right, the filter will be completely unnecessary.

I'm just trying to save you money and time.

But that isn't the only reason for a SSF. Eliminating the need for the amp to try and reproduce any information below 25Hz or so will free it up to reproduce the rest of it's passband. Unless you are running an amp that was built to never run out of steam (which there are very few of those on the market!) then running an SSF can actually help out even in a sealed alignment. Just my .02 though so take it for what you will.

89grand

· #15 · Apr 28, 2009

Well maybe with a turn table where there is unnecessary low frequency rumble, but with a CD player I don't see that being any issue. My feeling is that a SSF is used for the purpose of keeping frequencies much below the tuning frequency from damaging a driver in a ported enclosure. If the sub is sealed or the tuning is low enough, there shouldn't really be any danger of damage.

I don't think many CD's have any sub 30hz content anyway.

Boostedrex

· #16 · Apr 28, 2009

I'm not talking about damage to the driver or messing with the source unit. I'm talking about the amp struggling to reproduce subsonics when it isn't built beefy enough to do that. And when you make any amp struggle to do something, it will lose quality.

89grand

· #17 · Apr 28, 2009

Boostedrex said:
I'm not talking about damage to the driver or messing with the source unit. I'm talking about the amp struggling to reproduce subsonics when it isn't built beefy enough to do that. And when you make any amp struggle to do something, it will lose quality.

OK, but what CD is going to have all of this low frequency information that needs to be removed before the amp?

Very little music contains sub 30hz info. That's what I meant.

If you have a SSF filter set to filter out 25hz and below, but there isn't anything there anyway, what good does it do?

Boostedrex

· #18 · Apr 28, 2009

89grand said:
OK, but what CD is going to have all of this low frequency information that needs to be removed before the amp?

Very little music contains sub 30hz info. That's what I meant.

If you have a SSF filter set to filter out 25hz and below, but there isn't anything there anyway, what good does it do?

I'll agree that there aren't a lot of CD's with info down there. In fact, I argue that point all the time. However in organ music, demo CD's, some orchestral work, and other such things there is information down there. You could even set the SSF up higher and really not miss anything thanks to cabin gain. Then you'd be making it even easier on your entire system. When I was running the Mag v4 in my car I bumped the SSF up to 36Hz with a 12db/oct slope.

NOTORIOUS97200

Discussion Starter · #19 · Apr 29, 2009

Looking for some info online, I can see a lot of processors, and 2 or 3-way crossovers.
I don't know what to try ! I am looking for something I can hook between the sub pre-out of the h u and the sub itself.
So, I just know I don't want the Epicenter (they do not work from sub pre-out).
Are 2-way electronic crossovers (with ssf of course) good for what I need ?
Can you give me examples, and mainstream brands ( I can only buy online because I live far away from the USA) ?
I have seen the Soundstream ones, bx10, bx15,..., MTX (not the RE-Q ), and tons of others !!!!!
So ? Which ones to get ?

VP Electricity

· #20 · Apr 29, 2009

NOTORIOUS97200 said:
Looking for some info online, I can see a lot of processors, and 2 or 3-way crossovers.
I don't know what to try ! I am looking for something I can hook between the sub pre-out of the h u and the sub itself.
So, I just know I don't want the Epicenter (they do not work from sub pre-out).
Are 2-way electronic crossovers (with ssf of course) good for what I need ?
Can you give me examples, and mainstream brands ( I can only buy online because I live far away from the USA) ?
I have seen the Soundstream ones, bx10, bx15,..., MTX (not the RE-Q ), and tons of others !!!!!
So ? Which ones to get ?

Why not buy an AudioControl 2xs and use the PFM ("Programmable Frequency Match", silly) feature as a subsonic? The chip inside might already be the value you want. The 2XS sounds better than many amp xovers and is also a nice line driver...

1 - 20 of 22 Posts

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