IB system low frequency only?

[pointzero]

Hi,

Just moved over to an IB system from an active sub box.
I have two "FI IB3s 18s" which are powered by an EP4000.

i am finding that the quality of the bass is very clean and excellent with very low frequency bass (shaking the room) but not very good with the upper bass, meaning no punch, as there should be imo for movies n music. I can feel the bass but not hear it if that makes sense, im sure you're meant to hear it to as well as feeling it too, as i did with my bass box?

Is there anything wrong, or is this how an IB system sounds?

Thanks for any replies.

[ThomasW]

Often this situation occurs when the new IB owner is used to a bloated upper bass typical of many box subs

To diagnose the situation we need to know specifics about the install (Floor plan, sub placement, type of main speakers, etc) and to see some in room frequency response plots.

[pointzero]

This is my manifold

Attachments:

[pointzero]

From my attic pic

Attachments:

[Ile]

What is attic room dimensions?

Back spaces room modes could cause dip to upper bass region in your listening room.

[pointzero]

The attic dimensions are:

Floor: 15ft x 14ft

Height peak: 7ft

And ceiling obviously a typical uk shape with both coming down to the floor.

Listening area:

15ft x 30ft

Height: 9ft

[pointzero]

My manifold is about one metre in from the side wall and one foot in front of listening position which is in the centre of the room.
(please see pic)

Attachments:

[pointzero]

Jan 21, 2012 18:37:48 GMT -7 ThomasW said:

Often this situation occurs when the new IB owner is used to a bloated upper bass typical of many box subs

To diagnose the situation we need to know specifics about the install (Floor plan, sub placement, type of main speakers, etc) and to see some in room frequency response plots.

Sorry i do not know how to do frquency plots.
My main speakers are Spendor S9s and the centre is a spendor C9.

Please look at pics above to give you an idea of my manifold and sub placement.

[ThomasW]

Your statement is pretty typical of someone who's just moved from a box sub response with not very flat frequency response to a IB. The impression of something missing is because it was actually boosted by the box sub.

Not having the ability to do frequency response plots means we won't have the necessary information to answer your question.

Even if the IB were lacking in the 60Hz-120Hz area (chest compression) EQ can quickly fix that, but again we need response plots to accurately dial in the EQ settings.

My suggestion is to get a good SPL meter or measurement mic and download software to make accurate system measurements. Lacking info about the measured frequency response means any answers are just blind guesses.

[pointzero]

I appreciate your suggestion so ill place an order for a SPL meter, and take it from there.

Also i do not have any sort of EQ.

Should i get one?

[ThomasW]

What's your system? If it's a receiver or pre/pro most have built-in EQ but it's usually not accurate enough for our needs.

Per our FAQ section, most people use one of the Behringer BFD's for EQ. The easiest one to use is the FBQ2496. Slightly cheaper but more user hostile is the Behringer DSP1124P

If you've not seen this resource section then start your research....
home.comcast.net/~thomasw-2/SubwooferSetupandEQpage5.html

[pointzero]

I have a processor which is the "Audiolab 8000AP" which has no built in EQ.

I was looking at the "antimode 8033s" hows that compared to the behringer?

Thanks for the link, ill give it a read.

[Ile]

Jan 22, 2012 14:10:16 GMT -7 pointzero said:

I was looking at the "antimode 8033s" hows that compared to the behringer?

Antimode is easy to use device for cutting peaks from response, but it wont boost dip areas that might be needed in your situation.

[chrisbee]

The first question which springs to mind is your crossover and its setting. Are you using the 8000AP for your crossover? I'm not familiar with the Audiolab kit and a quick browse gave no obvious clue.

EDIT: Found a review.- You have a variable frequency crossover from 40-120Hz 24dB/octave.

Try playing with the frequency setting to see if it helps.

Another question: Did you run your speakers full range when you had your active sub?

[pointzero]

Jan 23, 2012 3:24:29 GMT -7 Ile said:

Jan 22, 2012 14:10:16 GMT -7 pointzero said:

I was looking at the "antimode 8033s" hows that compared to the behringer?

Antimode is easy to use device for cutting peaks from response, but it wont boost dip areas that might be needed in your situation.

Thanks for that clarification..

I have got the Behringer FBQ2496, This morning.

Ill give it a go tonight after reading and understanding the instructions.

[pointzero]

Jan 23, 2012 12:21:31 GMT -7 @chrisbee said:

The first question which springs to mind is your crossover and its setting. Are you using the 8000AP for your crossover? I'm not familiar with the Audiolab kit and a quick browse gave no obvious clue.

EDIT: Found a review.- You have a variable frequency crossover from 40-120Hz 24dB/octave.

Try playing with the frequency setting to see if it helps.

Another question: Did you run your speakers full range when you had your active sub?

I have my processor set to 80hz on all my speakers.

I had this setting with my active sub too.

Please check out my link below for my processor:
www.hifix.co.uk/pdf/107637.pdf

[chrisbee]

Jan 24, 2012 8:23:26 GMT -7 pointzero said:

I have my processor set to 80hz on all my speakers.

I had this setting with my active sub too.

Please check out my link below for my processor:
www.hifix.co.uk/pdf/107637.pdf

It was worth asking. Anyone using Audiolab is more likely to be audio orientated. Suggesting you might have had a REL and were using it to reinforce your full range speakers for music. (it was only a wild guess)

As already suggested; you ideally need some in-room frequency plots to support your EQ efforts.

[pointzero]

Jan 24, 2012 10:13:22 GMT -7 @chrisbee said:

Jan 24, 2012 8:23:26 GMT -7 pointzero said:

I have my processor set to 80hz on all my speakers.

I had this setting with my active sub too.

Please check out my link below for my processor:
www.hifix.co.uk/pdf/107637.pdf

It was worth asking. Anyone using Audiolab is more likely to be audio orientated. Suggesting you might have had a REL and were using it to reinforce your full range speakers for music. (it was only a wild guess)

As already suggested; you ideally need some in-room frequency plots to support your EQ efforts.

I really appreciate you trying to help Thanks!

I have only just ordered the spl meter, soon as i get it in ill do some research on how to get some plots done and posted.

Just for reference, I had the "SVS PB12-Plus/2" then moved to the IB system, which im finding that the chest pounding bass that the SVS gave is just not there in the IB.

"But just to add the low frequencies on the IB is on another level for movies only, and for music theres hardly any bass at all from the IB"

[chrisbee]

Jan 24, 2012 10:41:15 GMT -7 pointzero said:

I have only just ordered the spl meter, soon as i get it in ill do some research on how to get some plots done and posted.

Just for reference, I had the "SVS PB12-Plus/2" then moved to the IB system, which im finding that the chest pounding bass that the SVS gave is just not there in the IB.

"But just to add the low frequencies on the IB is on another level for movies only, and for music theres hardly any bass at all from the IB"

Without an SPL meter and a basic frequency response plot it is rather difficult to judge relative subwoofer:speaker levels. You have quite a large room. Which favours the bottom end but offers not much "cabin gain" higher up.

That said, if the SVS filled it adequately then an IB can be made to do so too. The PB12 Plus/2 was a real belter, by all reports, but will have been voiced higher in the frequency range than an iB. It probably wasn't physically large enough to be very low tuned with two drivers in a bandpass alignment.

Don't get too depressed with your present results. Wait until you have a frequency curve to see exactly what is happening in your room. REW and EQ-ing can become a complete hobby in itself. Just ask my wife! ;D

[genesplitter]

pointzero, which SPL meter did you get to measure frequency response?