Low output below 35-40hz and High QTS in a ported enclosure

[ahl395 0]

Hi everyone, first post here.

I have an Fi Q 12, I ordered it fully loaded with the high QTS option with the intention to use it in a sealed enclosure. I currently have it in a 1cu ft box.

Unfortunately the sub response really rolls off below 35-40hz, which is very disappointing. I have had much lower end subwoofers in sealed boxes that were actually much better on the low end frequencies. So my thoughts are to try it in a ported enclosure and see how it responds.

Problem is I have High QTS. What will happen and how will the sub react to a ported enclosure?

If anyone has any input on how else to solve my issue or any ideas about the enclosure let me know, it's greatly appreciated.

[Fi 4 life 0]

Can you fit a bigger box? What amp are you using?

[ahl395 0]

Can you fit a bigger box? What amp are you using?

I can fit a bigger box. I believe that the recommended ported enclosure by Fi is a bit too big though, but I need to measure to make sure. I will do that a bit later and post back.

I'm using a Hifonics Mt. Olympus Hercules. It puts out 2000W x 1 @ 1 ohm. I have set the gains with a DMM and calculated for 1800W. Still waiting to get an oscilloscope to set them right. It has a clipping indicator that I watch like a hawk in the mean time

[Fi 4 life 0]

Make a bigger box and get back to us

[lithium 358]

is the enclosure 1 cu ft net before or after subwoofer displacement? 

 

probably just needs to loosen up. I would try a few other things first. first you can simulate a large box by reversing the woofer in the enclosure and/or adding polyfil. another idea would be to move the enclosure around the trunk (close the the trunk lid is typically best). 

[Shogen 325]

is the enclosure 1 cu ft net before or after subwoofer displacement?

probably just needs to loosen up. I would try a few other things first. first you can simulate a large box by reversing the woofer in the enclosure and/or adding polyfil. another idea would be to move the enclosure around the trunk (close the the trunk lid is typically best).

All of this... If the first 2 things give you better sound then you should make a bigger enclosure.

Did someone ask about ssf? You could turn it off

[lithium 358]

 

is the enclosure 1 cu ft net before or after subwoofer displacement?

probably just needs to loosen up. I would try a few other things first. first you can simulate a large box by reversing the woofer in the enclosure and/or adding polyfil. another idea would be to move the enclosure around the trunk (close the the trunk lid is typically best).

All of this... If the first 2 things give you better sound then you should make a bigger enclosure.

Did someone ask about ssf? You could turn it off

 

 

or just set it pretty low if you're playing some really ridiculous low frequency shit. 25hz or so 

[cloud77 28]

1 cu. ft is what they recommend for the SSD.  For the Q, you will need about 1.5-1.8

[ahl395 0]

Make a bigger box and get back to us

 

Bigger sealed, or bigger ported?

 

 

is the enclosure 1 cu ft net before or after subwoofer displacement? 

 

probably just needs to loosen up. I would try a few other things first. first you can simulate a large box by reversing the woofer in the enclosure and/or adding polyfil. another idea would be to move the enclosure around the trunk (close the the trunk lid is typically best). 

 

1cu. ft before the sub.

 

I've had it for about two weeks now and I drive quite a bit so I think its almost done breaking in. But maybe some more time will help.

 

By reversing you mean reversing the phase or mounting the subwoofer with the motor facing out and the cone facing into the box? Reversing the phase does help alot, if that tells you anything.

 

 

is the enclosure 1 cu ft net before or after subwoofer displacement?

probably just needs to loosen up. I would try a few other things first. first you can simulate a large box by reversing the woofer in the enclosure and/or adding polyfil. another idea would be to move the enclosure around the trunk (close the the trunk lid is typically best).

All of this... If the first 2 things give you better sound then you should make a bigger enclosure.

Did someone ask about ssf? You could turn it off

 

 

The subsonic filter is set pretty low. I believe the amp starts at 15hz and its only turned up a hair from the minimum, so I'm guessing around 20hz, nowhere near 30hz.

 

 

 

 

[ahl395 0]

1 cu. ft is what they recommend for the SSD.  For the Q, you will need about 1.5-1.8

 

Well Fi says .8-1.5 cu. ft. Would going from 1 cu. ft to 1.5 make much of a noticeable difference?

[cloud77 28]

The box Fi provides cut sheets for is 1.25 cubes.  I would do that.  You should have a noticeable difference with a larger sealed box.  even if its less than .5 cubes

[ahl395 0]

The box Fi provides cut sheets for is 1.25 cubes.  I would do that.  You should have a noticeable difference with a larger sealed box.  even if its less than .5 cubes

 

Okay. If i could fit 1.5, would I benefit from it? 

[cloud77 28]

its worth a try.  You can build a sealed box in a flash

[Shogen 325]

Yes it's worth it to YOU since you want better low end. But only way to really know it's too build it.

I have an xcon in 3.28 sealed. Really pushed the lows

[ahl395 0]

Okay, sounds good. I'll work on that.

 

Thanks everyone.

[lithium 358]

mount the subwoofer with the motor outside the box. the Q's displacement is .16 cu ft. so currently your box is effectively  .84 cu ft. if you reverse mount the sub and add polyfil you can simulate what how the box would perform if the box was ~30% larger (according to this http://www.glasswolf.net/papers/polyfill.html). which would be ~1.3 cu ft. 

 

remember if you decide to build a new enclosure to include the woofer displacement in the calculation. 

Edited April 8, 2014 by lithium

[///M5 2,833]

And don't use either a DMM or O'scope.  And no, your clipping indicator doesn't work either.  You have two ears, use them.

[ahl395 0]

mount the subwoofer with the motor outside the box. the Q's displacement is .16 cu ft. so currently your box is effectively  .84 cu ft. if you reverse mount the sub and add polyfil you can simulate what how the box would perform if the box was ~30% larger (according to this http://www.glasswolf.net/papers/polyfill.html). which would be ~1.3 cu ft. 

 

remember if you decide to build a new enclosure to include the woofer displacement in the calculation. 

 

Will do. Thanks!

 

 

And don't use either a DMM or O'scope.  And no, your clipping indicator doesn't work either.  You have two ears, use them.

 

Do you suggest using a familiar song or test tones when setting gains by ear? I've read it's best to use tones since its very easy to hear distortion.

 

As far as clipping on my sub goes, I can't hear distortion when the clipping indicator comes on, it just sounds louder. I've heard the indicators are pretty accurate though, because they measure the rail voltage in the amp or something along those lines. 

[lithium 358]

 

mount the subwoofer with the motor outside the box. the Q's displacement is .16 cu ft. so currently your box is effectively  .84 cu ft. if you reverse mount the sub and add polyfil you can simulate what how the box would perform if the box was ~30% larger (according to this http://www.glasswolf.net/papers/polyfill.html). which would be ~1.3 cu ft. 

 

remember if you decide to build a new enclosure to include the woofer displacement in the calculation. 

 

Will do. Thanks!

 

 

And don't use either a DMM or O'scope.  And no, your clipping indicator doesn't work either.  You have two ears, use them.

 

Do you suggest using a familiar song or test tones when setting gains by ear? I've read it's best to use tones since its very easy to hear distortion.

 

As far as clipping on my sub goes, I can't hear distortion when the clipping indicator comes on, it just sounds louder. I've heard the indicators are pretty accurate though, because they measure the rail voltage in the amp or something along those lines. 

 

clipping is fine, its just distortion. distortion is only a problem when its audible. so the clipping light doesn't convey to the user anything significant. the light is just a gimmick. 

 

 

use a variety of songs. basically you're just trying to get close to some value that maximizes the output. so for songs that are recorded at a lower level you can increase the volume at the hu and match the output to songs recorded at a higher level. setting the gain is never foolproof, you should always be listen for distortion and speaker stress.

[altoncustomtech 773]

 

 

mount the subwoofer with the motor outside the box. the Q's displacement is .16 cu ft. so currently your box is effectively  .84 cu ft. if you reverse mount the sub and add polyfil you can simulate what how the box would perform if the box was ~30% larger (according to this http://www.glasswolf.net/papers/polyfill.html). which would be ~1.3 cu ft. 

 

remember if you decide to build a new enclosure to include the woofer displacement in the calculation. 

 

Will do. Thanks!

 

 

And don't use either a DMM or O'scope.  And no, your clipping indicator doesn't work either.  You have two ears, use them.

 

Do you suggest using a familiar song or test tones when setting gains by ear? I've read it's best to use tones since its very easy to hear distortion.

 

As far as clipping on my sub goes, I can't hear distortion when the clipping indicator comes on, it just sounds louder. I've heard the indicators are pretty accurate though, because they measure the rail voltage in the amp or something along those lines. 

 

clipping is fine, its just distortion. distortion is only a problem when its audible. so the clipping light doesn't convey to the user anything significant. the light is just a gimmick. 

 

 

use a variety of songs. basically you're just trying to get close to some value that maximizes the output. so for songs that are recorded at a lower level you can increase the volume at the hu and match the output to songs recorded at a higher level. setting the gain is never foolproof, you should always be listen for distortion and speaker stress.

 

 

+1 to you, probably the best way I've seen that said in awhile.

 

Also, as Lithium pointed out if the box is 1 cu.ft. before you put the sub in it then the volume is all the way down at the low end for the sub.  If you do as he said, turn the sub around in the box and add some polyfil I think you'll be very surprised at how much better it sounds and performs.  

[ahl395 0]

clipping is fine, its just distortion. distortion is only a problem when its audible. so the clipping light doesn't convey to the user anything significant. the light is just a gimmick. 

 

 

use a variety of songs. basically you're just trying to get close to some value that maximizes the output. so for songs that are recorded at a lower level you can increase the volume at the hu and match the output to songs recorded at a higher level. setting the gain is never foolproof, you should always be listen for distortion and speaker stress.

 

So your saying for the most part, I don't have to worry much about clipping unless it's audible distortion? From what I've read I thought clipping was usually not audible.

 

mount the subwoofer with the motor outside the box. the Q's displacement is .16 cu ft. so currently your box is effectively  .84 cu ft. if you reverse mount the sub and add polyfil you can simulate what how the box would perform if the box was ~30% larger (according to this http://www.glasswolf.net/papers/polyfill.html). which would be ~1.3 cu ft. 

 

remember if you decide to build a new enclosure to include the woofer displacement in the calculation.

 

Will do. Thanks!

 

 

And don't use either a DMM or O'scope.  And no, your clipping indicator doesn't work either.  You have two ears, use them.

 

Do you suggest using a familiar song or test tones when setting gains by ear? I've read it's best to use tones since its very easy to hear distortion.

 

As far as clipping on my sub goes, I can't hear distortion when the clipping indicator comes on, it just sounds louder. I've heard the indicators are pretty accurate though, because they measure the rail voltage in the amp or something along those lines.

clipping is fine, its just distortion. distortion is only a problem when its audible. so the clipping light doesn't convey to the user anything significant. the light is just a gimmick. 

 

 

use a variety of songs. basically you're just trying to get close to some value that maximizes the output. so for songs that are recorded at a lower level you can increase the volume at the hu and match the output to songs recorded at a higher level. setting the gain is never foolproof, you should always be listen for distortion and speaker stress.

 

+1 to you, probably the best way I've seen that said in awhile.

 

Also, as Lithium pointed out if the box is 1 cu.ft. before you put the sub in it then the volume is all the way down at the low end for the sub.  If you do as he said, turn the sub around in the box and add some polyfil I think you'll be very surprised at how much better it sounds and performs.

I was going to unfortunately I realized I don't have the space my trunk to do so. So I'm going to work on building a 1.5 cube box.

[Fi 4 life 0]

Before or after displacement?

[ahl395 0]

Before or after displacement?

Well I just measured how big a box I can fit in my car. I'll have about 1.3 - 1.4 cubes after displacement.

Edited April 9, 2014 by ahl395

[///M5 2,833]

Setting the gain is a joke.  Just set it so you can exceed what your driver can and then INTELLIGENTLY use your ears on EVERY song.  No need for "setting" as it won't save you anyways.  The goal with setting should be to make the whole system perform as one (left that subjective on purpose).  Doing anything else is a waste of time.

 

If of course you have a magically level matched music collection I can see exceptions, but you still should actually listen to your music as that is somewhat the point.

[ahl395 0]

Setting the gain is a joke.  Just set it so you can exceed what your driver can and then INTELLIGENTLY use your ears on EVERY song.  No need for "setting" as it won't save you anyways.  The goal with setting should be to make the whole system perform as one (left that subjective on purpose).  Doing anything else is a waste of time.

 

If of course you have a magically level matched music collection I can see exceptions, but you still should actually listen to your music as that is somewhat the point.

 

Makes sense to me, thanks for the explanation.