# First graphs, not very flat



## B_Pay (Sep 15, 2009)

Hey everyone,

These are a couple of graphs for my sub and speakers...this doesn't look very good does it??

B&W 804S mains and HSU STF3 sub in a 12x18x8 room.









Graph with smoothing


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## MikeD (Jul 18, 2009)

Can you position your sub somewhere else?


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## B_Pay (Sep 15, 2009)

Possibly, I'll see if I can find another spot for it.

What's up with the 100-300 hz range?


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## Wayne A. Pflughaupt (Apr 13, 2006)

That is certainly curious. You might try measuring each front speaker separately.

P.S. Welcome to the Forum!

Regards,
Wayne


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## B_Pay (Sep 15, 2009)

I'm having trouble posting the graphs but I did redo it with a new sub placement. Not much difference really. I did raise my levels prior to running it this time and that seemed to help a little bit with the 100-300hz range. My sub still has a large increase at around 20hz and a big dip at just over 40hz. I'll try and post em later.

Thanks for your insight and welcoming me to the forum.


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## tonyvdb (Sep 5, 2007)

What are you running for a crossover on the sub and do you have the B&Ws running full range or do you have a HPF set for that as well?


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## brucek (Apr 11, 2006)

> I'm having trouble posting the graphs


Go to the post padding thread and put in enough posts (5) so you can post graphs..... 

brucek


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## B_Pay (Sep 15, 2009)

tonyvdb said:


> What are you running for a crossover on the sub and do you have the B&Ws running full range or do you have a HPF set for that as well?


The crossover for the sub is set at 100hz and the B&W's are set at Large.

Emailed HSU and they recommended an external EQ device like Antimode 8033. I looked into this but I have a few questions on it. Would a receiver with Audyssey MultEq do the same thing as this Antimode 8033? I need a new receiver anyway so I'm hoping that is the case. If not I'd rather do it myself using the Behringer which is much cheaper. It's my understanding that it will require a little more work on my part.

The other option is that HSU offered to modify my amplifier to give me an overdamped (more rolled off) response to help reduce the deep bass peak. My sub is currently set for Max Extension so I'm not sure if that is adding to this deep bass peak issue. 

I'd like to see what some of you guys think....and girls if there are any in here.


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## seattle_ice (Jul 12, 2006)

What is the layout of your room and where are the sub and speakers positioned now?


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## brucek (Apr 11, 2006)

> an external EQ device like Antimode 8033. I looked into this but I have a few questions on it. Would a receiver with Audyssey MultEq do the same thing as this Antimode 8033? I need a new receiver anyway so I'm hoping that is the case. If not I'd rather do it myself using the Behringer which is much cheaper. It's my understanding that it will require a little more work on my part.


The BFD is much cheaper than the Anti-Mode, but does require a bit of time educating yourself. There are lots of people here that can help with that.
Audyssey doesn't seem to be able to tame the large resonant peaks, so most people here use a BFD to take care of the major bumps in the response of the sub and then run Audyssey to smooth it all out along with the full range EQ it performs.



> The other option is that HSU offered to modify my amplifier to give me an overdamped (more rolled off) response to help reduce the deep bass peak. My sub is currently set for Max Extension so I'm not sure if that is adding to this deep bass peak issue.


I would personally not go this route. I would add a BFD and get a new receiver with Audyssey as the best option.


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## MikeD (Jul 18, 2009)

B_Pay said:


> The crossover for the sub is set at 100hz and the B&W's are set at Large.
> 
> Emailed HSU and they recommended an external EQ device like Antimode 8033. I looked into this but I have a few questions on it. Would a receiver with Audyssey MultEq do the same thing as this Antimode 8033? I need a new receiver anyway so I'm hoping that is the case. If not I'd rather do it myself using the Behringer which is much cheaper. It's my understanding that it will require a little more work on my part.
> 
> ...


You should definitely set your speakers to small and set your crossover on your sub to max then set the receiver's crossover to 80hz.


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## lsiberian (Mar 24, 2009)

Can you turn off the max extension setting?

I think eqing the bass part won't be too difficult. I'd try a higher crossover. I get really jacked up sound with an 80hz x-over in my room, but at 100hz it's much improved.


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## Wayne A. Pflughaupt (Apr 13, 2006)

B_Pay said:


> The other option is that HSU offered to modify my amplifier to give me an overdamped (more rolled off) response to help reduce the deep bass peak.


Deep bass peak? Looks to me more like a big depression between 15-60 Hz. :bigsmile:



> My sub is currently set for Max Extension so I'm not sure if that is adding to this deep bass peak issue.


Well if you have another option for less extension, that might be the ticket. The BFD isn't the best choice for dealing with sub-20Hz problems.

Regards,
Wayne


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## MikeD (Jul 18, 2009)

OP needs to test just the sub and that should tell a lot.


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## weverb (Aug 15, 2008)

From past experience with HSU subs, try switching the sub to "max ouput" and you will see that 30-50Hz section improve. You will probably loose some low end. The low end can be helped by placing the sub near a corner. I would also do as mentioned before, set the mains to small and try a 80Hz. cross over.


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## B_Pay (Sep 15, 2009)

So I messed around with the crossovers a bit and think I got it much better than from where I first started. I still kept my receiver at large for my fronts because the response doesn't change any. What I did do however, was put the crossover on the sub to around 55hz. This got rid of a large hump after 50hz.

My sub can't be modified to max output instead of max extension because it is an HSU STF, not a VTF. Although technically I think all I need to do is add a subsonic filter to it and remove the port plug.

Here is the graphs with smoothing...The first one is the current more practical placement that i'm leaving it at.









Here is the sub in another spot, I don't like the dip at 30-40hz, but it does tame the under 20hz peak a bit.









So I'm seriously considering getting a BFD and I have quite a few questions on them that may be best answered in another thread but I'll start here.

Can someone summarize the differences between the following Behringer models:

DCX2496 ~300 dollars
DEQ2496 ~300 dollars
FBQ2496 ~150 dollars
DSP1124P ~100 dollars

I'd like to understand what features each has and why it is or isn't necessary for my application. Do any of these have a subsonic filter that I can use to attempt the max output mode instead of max extension.

Thanks for the input!


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## Wayne A. Pflughaupt (Apr 13, 2006)

B_Pay said:


> Can someone summarize the differences between the following Behringer models:
> 
> DCX2496 ~300 dollars
> DEQ2496 ~300 dollars
> ...


All you need is equalization, which the DSP1124 will provide. The other models pile on other functions on top of that that you really don't need for equalizing a subwoofer.




> Do any of these have a subsonic filter that I can use to attempt the max output mode instead of max extension.


You can check the manuals at Behringer's website to see, but you might first determine if you even need a subsonic filter. The only reason you'd need one would be if you were having problems over-driving the sub, and you haven't indicated that you're having that problem. Also, as others have noted, the sub has its own built in filter, and it appears that you haven't utilized it yet. Shouldn't you try that first? :huh:

Regards,
Wayne


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## B_Pay (Sep 15, 2009)

Wayne A. Pflughaupt said:


> All you need is equalization, which the DSP1124 will provide. The other models pile on other functions on top of that that you really don't need for equalizing a subwoofer.
> 
> 
> You can check the manuals at Behringer's website to see, but you might first determine if you even need a subsonic filter. The only reason you'd need one would be if you were having problems over-driving the sub, and you haven't indicated that you're having that problem. Also, as others have noted, the sub has its own built in filter, and it appears that you haven't utilized it yet. Shouldn't you try that first? :huh:
> ...


I think the problem is that I don't quite understand what a subsonic filter is and when it becomes necessary. The reason I have not removed the port plug from my sub is because HSU told me the following:

"Definitely do not remove the port plug from your unit, as this would raise the
port tuning and potentially cause damage to the driver due to no subsonic
filtering directly below port tuning."

I do, however, have a Low Pass filter on the sub which I am using...I've set it to 55hz. My mains have a much more linear response above 55hz. It's my understanding that this filter is not the same as a subsonic filter...Is that correct?

The volume knob on my sub is not even half way so I don't think I have an issue with overdriving the sub as you mentioned. If I can get away with removing the plug and not blowing up the sub I would love to try it and see if that solves my under 20hz peak.


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## MikeD (Jul 18, 2009)

I think the second position is the best if you can boost that dip successfully (and if you can't reduce the 20hz hump in the first). Can you post a waterfall of both sub positions? You don't have to redo the measurements, just as long as you saved them. Try to set the time to around 800ms as the default 300ms is just way too short imo.


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## weverb (Aug 15, 2008)

I would just go with the BFD because you don't need additional cross overs, time adjustments, etc. I would just place a wide filter at 20 Hz. and that will help bring down that peak. It is probably coming from the sub being placed near a corner. Even if there is still a small hump remaining, I doubt you will be able to hear the difference. Overall, that first graph looks awesome.

You may want to also graph just the sub. It may be adding to those peaks above the cross over point. You may be able to correct them with the BFD if the sub is causing the peaks. If the sub is not causing the peaks, some acoustical treatment might help out.


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## Wayne A. Pflughaupt (Apr 13, 2006)

B_Pay said:


> I do, however, have a Low Pass filter on the sub which I am using...I've set it to 55hz. My mains have a much more linear response above 55hz. It's my understanding that this filter is not the same as a subsonic filter...Is that correct?


Correct – that’s the filter that determines where your subs and mains divide.



> The volume knob on my sub is not even half way so I don't think I have an issue with overdriving the sub as you mentioned. If I can get away with removing the plug and not blowing up the sub I would love to try it and see if that solves my under 20hz peak.


Can’t hurt to try – just be on the “look out” (“listen-out?”) for rude noises coming from the sub with demanding passages in movies. That’ll be your indicator that its being overdriven.

Personally I like the first graph better. The second one has a couple of narrow dips. Those are often nulls, and nulls can’t be equalized.

Regards,
Wayne


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## B_Pay (Sep 15, 2009)

I took the plug out and put it right back in....sub didn't like it...Took a more ear level reading and here is the graph with smoothing and waterfall. I think it looks much better than where I started...thanks for everyone's help. I didn't put the plug as far in and this may have helped ??

Is it customary to give a smoothing version? The regular version is very erratic.
















This REW program is Great!...I'm learning a bit of what the waterfall is but all these other things I have no clue. Any suggestions on where to look to understand this stuff better?


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## weverb (Aug 15, 2008)

You need to post the waterfall with the same settings as your REW plots (i.e. 45-105, etc.). Also use a max of 600ms and not 800.


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## B_Pay (Sep 15, 2009)

I can change it to 600 instead of 800 but the graph isn't legible when I pick 12hz - 3000hz??


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## B_Pay (Sep 15, 2009)




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## weverb (Aug 15, 2008)

B_Pay said:


> I can change it to 600 instead of 800 but the graph isn't legible when I pick 12hz - 3000hz??


Sorry, I just meant the vertical axis. The horizontal usually only goes from 20 to 200 Hz. There is usually nothing you can do about waterfall plots below 30Hz.


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## Jakeman02 (Jul 3, 2006)

I'm not understanding what your meaning is by HSU told you not to run it in Max Output mode. The VTF3 is made to be run in both configurations but when running both ports open you need to adjust the Bass Extension Mode Switch on the back of the sub accordingly.....see page 5 of the manual. 

Either way you run it the sub will be fine as long as you have the switch adjusted in the right position. From what I'm seeing I would definitely try Max Output mode again as you're getting some outrageous low end boost and Max Output mode should help with some of that while giving you more output in the area where your depression is....then work from there.


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## B_Pay (Sep 15, 2009)

Jakeman02 said:


> I'm not understanding what your meaning is by HSU told you not to run it in Max Output mode. The VTF3 is made to be run in both configurations but when running both ports open you need to adjust the Bass Extension Mode Switch on the back of the sub accordingly.....see page 5 of the manual.
> 
> Either way you run it the sub will be fine as long as you have the switch adjusted in the right position. From what I'm seeing I would definitely try Max Output mode again as you're getting some outrageous low end boost and Max Output mode should help with some of that while giving you more output in the area where your depression is....then work from there.


I have the discontinued STF-3 model, not the VTF-3. It's not adjustable on mine...i can send the amp back to HSU and have them adjust it for me.


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## MikeD (Jul 18, 2009)

It looks like you have some outside noise at 60hz. That happened to me the other day. There was a truck down the street that was grinding branches and in my waterfalls I had this awful decay time for a certain frequency then it magically disappeared when the truck left.


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## tonyvdb (Sep 5, 2007)

Have you tried playing with the subs phase control? that can also get rid of dips in the frequency range.


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## B_Pay (Sep 15, 2009)

Actually I forgot to mention that I did... and this made a big difference in the 30-50hz range. Good tip.


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