# Subwoofer LFE adjustment questions...



## Darren (Apr 20, 2006)

*Questions on Adjusting Subwoofer Signal *
« Thread Started on *Today* at 8:56am »  Hi Guys,

I'm looking for a little clarity on adjusting the signal properly starting from the receiver and ending at the amp.

Currently I have my AV receiver LFE level at -10, my mains are in the neighborhood of -6 on average. I have my EP2500 set at about 12:00. At these settings the amp is clipping on scenes like Star Wars Attack of the Clones Scene 1 with the ship fly by etc... Also on LOTR FOTR scene 1 ring drop. I would think this amp should be able to be turned up significantly more than 12:00 at these settings before clipping. When it does clip the drivers definately let you know, they fall flat on their face. 

4 RL-P 15's bridged mono for 4ohm load

How are you configured? Does my configuration and experience sound normal?


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## Josuah (Apr 26, 2006)

The amp's gain is how much it adds to the input signal, not the maximum volume it will output. So if the gain is set at max, but you feed it a tiny signal, it will not play loud, and if the gain is set to min, and it feed it a huge signal, it will play loud.

Sounds like you just need more subwoofer for your listening levels. What's the SPL of the sub at your listening position at those scenes where you are having problems?


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## Darren (Apr 20, 2006)

He he, 118db give or take... I'm just trying to tune my maximum output so I don't exceed the drivers capability and the amp capability...basically tuning for worst case LFE scenario 

At normal HT listening levels I'd say the peaks are at 105db but an unexpectedly over-dynamic scene can clip the amp and the drivers still have much more headroom. That's what I'm a little worreid about. I want to minimize the possibility of excessive clipping at my normal listening levels. 

I have four RL-P 15's with 1,500 watts in an IB.

It sounds like I just have a strong signal going to the amp through the BFD then... this is good, I need to learn about how the signal is treated and amplfied. I've always just went on what I was told without learning why...now I'm wanting to learn why.


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## bobgpsr (Apr 20, 2006)

With pro amps IME you want to have their input gain levels cranked all the way clockwise. Big problems otherwise happen with the AVR clipping its LFE output. Unless you are trying to compensate for a SACD/DVD-A players' analog sub output level, I would set the AVR's LFE at 0 not -10.

I don't have a Behringer, but rather a Mackie M1400 and to get the input drive right I had to get an ART Cleanbox to get nominal +4 dBu pro level adequate drive. Home audio uses -10 dBV for nominal line levels.

Bob


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## Darren (Apr 20, 2006)

I'm not sure I am understanding completely...

My LFE output in the speaker level settings is set to -10, if I move it to 0 the amp will be getting a HUGELY increased signal, wouldn't that really clip the amp? Then if I set the amp all the way clockwise I'd be opening that signal all the way up which would make the situation worse right? Am I not thinking correclty?


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## bobgpsr (Apr 20, 2006)

I'm thinking of my Yamaha's case where it has both an LFE level (0 to -10dB) and a separate subwoofer channel level adjustment (with the other channel levels). What is your AVR again?

The LFE level that I am talking about is really only used for digital connections using DD or DTS and is not used for multichannel 5.1/7.1 analog inputs. Sorry for the confusion!

Bob


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## Darren (Apr 20, 2006)

I have an Onkyo TX-DS777 AV receiver. I'm using the LFE out 5.1. I have the LFE level adjustment within the speaker level settings at -10 (can be adjusted up and down in 1db increments above and below 0). I use this to set the subwoofer level in balance with the speakers. The signal reaching my BFD is strong but the BFD never goes out of the green range, the EP2500 will clip on extremely dynamic scenes when set at 12:00 in this configuration. When I say clip I don't mean a flicker, I mean solidly lit for more than a second. 

I might have it a little hot but I don't believe it should be clipping at these settings when listening at normal HT levels... Not sure what db I listen at, I have it turned up pretty well for HT listening.


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## bobgpsr (Apr 20, 2006)

Oh yeah -- the BFD input level meter! Hmmm sounds like your AVR sub line level drive is OK then. I've read where the Behringer amps have a input that can handle home audio line levels (unlike other pro amps).

So the clipping is in the EP2500. IME I've just gotten occassional brief flickers of the red clipping LEDs on my Mackie for extreme bass scenes -- WOTW tripods, opening of Serenity, 1812 cannons, etc. 
I'm driving a single 15" Tumult that is rated for 1000W at the voice coil with the Mackie bridged to output 1400W into 4 ohms. And I am able to bottom my sub when I run +10 dB over reference. So I set the Mackie's high pass rumble filter at ~18Hz and try to stay at reference level. Using it in a big 3000+ cubic ft basement room :sweat: 

Seems like your EP2500 driving 4 ohms is running out of oomfp before your 4 RL-P15's. :huh: Did you think of/consider wiring your array to 8 ohms instead? Much easier for the amp to drive -- but half the drive current pulled from the amp.

Bob


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## Darren (Apr 20, 2006)

Hm, I just did some calculations and I don't know where I came up with 4ohms... I have DVC 4 ohm drivers so the only possibilities for Bridged mono are 8ohms. *So I'm actually running 8ohms bridged mono* for 1,300 watts or 325 watts per driver.

I could 4 ohm stereo or 2 ohm stereo. I'm a little afraid of 2ohm stereo even though Behringer states it can handle it. 

At 8ohms bridged mono I'm seeing 1,300 watts or 325 per driver.

At 4 ohms stereo I'd also be seeing about 750 watts per channel or 325 per driver

At 2 ohms stereo I'd be seeing 1,200 watts per channel or 600 per driver

I'm not sure if going 4 ohms stereo would be better or not. I could try 2 ohms but like I said... that seems like it would be harder on the amp even in stereo.


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## bobgpsr (Apr 20, 2006)

Sorry to ask -- but just had to :dontknow:. Is your "bridged mono" connection using the two + outputs of the EP2500 --- I'll bet you are --- but I have seen some set the bridge switch and not changed the speaker connections to the bridged configuration. Just a thought.

Bob


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## Darren (Apr 20, 2006)

Yeah, I'm using just the two red outputs in the middle.


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## bobgpsr (Apr 20, 2006)

I'd try 4 ohm stereo. It is simple and easy. Plus the extra wires needed might give you a lower IR drop/better damping  But it not likely to solve the clipping problem.  

Bob


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## Darren (Apr 20, 2006)

Yeah, it will be easy, I have both sets of wires coming to the amp right now and just need to separate the mono connection to stereo and flip the dip switches etc... I don't even have to get in the attic for that. I have pairs of drivers at 4 ohms on separate leads that come to the amp and I then put those leads in series and into the amp.

I'll have to do that when I get home from work.


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## bobgpsr (Apr 20, 2006)

RL-P15 dual 4 ohm (D4)? or RL-P15 dual 2 ohm (D2)? Either way with four drivers I don't see how you don't have all possibilities (2, 4, 8, 16) ohms with the right series/parallel combinations.

Bob


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## Darren (Apr 20, 2006)

Dual 4 ohm... Not sure how I could get 4 ohm bridged mono though. I don't think it's possible.

I'm beginning to wonder if my "normal" level for HT might be a bit above normal too  I'll take measurement so we have an idea of what db level I'm having the issue at.


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## Sonnie (Apr 11, 2006)

With a dual 4 you end up with 2 or 8

... with 2 you get 1, 4 or 16

... with 4 you get .5, 2, 8, or 32

... I don't see a way to get to 4 with 4.


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## Darren (Apr 20, 2006)

Those are what I came up with too Sonnie.


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## bobgpsr (Apr 20, 2006)

Only use one 4 ohm coil on each driver? Have pairs of drivers at 8 ohms. Try 8 ohm stereo which would be the easiest load on the amp since your amp is running out of gas before your drivers. onder: 

Bob


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## Darren (Apr 20, 2006)

Ah, but that would change the damping of the driver right? I could do that though but the amp really shouldn't be running out of steam so I'd rather deal with that end but I'll try the other wiring options.


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## bobgpsr (Apr 20, 2006)

The amp might well be running out of current capability at low freqs. It may meet its specs at 1 kHz OK though. I seem to recall that it was a design copy of a QSC amp although the QSC had a much bigger power transformer. IIRC this was a criticism by QSC's Bob Lee. The QSC does cost a lot more though.

Bob


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## Darren (Apr 20, 2006)

Bigger transformer? I can't imagine a bigger one than what is in this thing  It must be 7" in diameter. Interesting observation though. Others are using this amp successfully though in similar setups. I might just be expecting too much from it.


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## bobgpsr (Apr 20, 2006)

Darren said:


> ...Ah, but that would change the damping of the driver right?...


It gives you the option of changing the drivers Q factor - via shorts or loads on the unused coil. IIRC leaving the coil open does not change much. Adire has a tech paper on it.

Bob


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## Darren (Apr 20, 2006)

Something that was brought to my attention that might make sense is that I have several filters on the BFD and I believe two of them have max boost. This could be what is over-driving my amp at certain frequencies causing it to clip when cranked. I'm going to experiment with these filters and see if I can do things differently.

I'll have to read that tech paper as well. Thanks!


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## bobgpsr (Apr 20, 2006)

Of course if you get much more amp -- then you will need a 20 amp house circuit to power it. I've popped the 15 A circuit which only drives my Mackie when I tried doing max SPL tests in my 3K^3ft room with sine waves :raped: Only got to 110 dB. So to do any outdoors GP testing I know I'll need a 20 A circuit. :surrender: 

Bob


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## Sonnie (Apr 11, 2006)

Seems like I remember ThomasW at the CULT and Mike at SoundSplinter telling us that both voice coils had to be used on the dual 4's. 

Darren, I would definitely try running the amp bypassing the BFD and see what happens.


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## Darren (Apr 20, 2006)

I'm going to switch to dual mono (amp in stereo) with 4 ohms per channel and will reduce the filter boost on those two filters and report my findings.


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## Darren (Apr 20, 2006)

Ok, just switched the amp to 4 ohm dual mono and that seems to have helped a little.

The amp is clipping on the ring drop scene at the end where the beast blows up in a sweeping tone. At the point where it clips badly I'm hitting 112db in the listening position using the old analog radio shack meter uncorrected. 

I have one filter that is +12db at 65Hz... I'm wondering if that is what is clipping the amp. I get flicker on the ring drop now but no solid red. I'm assuming that's because of the slightly less output at 4ohm dual mono and a little less strain on the amp.

Now, I need to fiddle with the LFE and gain.

Recommendations? Amp all the way up and LFE down? Not sure if there is enough room for that. I have the BFD at +4 and it doesn't clip at all. 

Currently I have set the sub to -10 or so in the speaker level adjustment in my receiver settings and the EP2500 is at 1:00.


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## Josuah (Apr 26, 2006)

Yeah, +12dB filter is extremely bad. Only do cuts, and then boost the overall volume. You may also be bottoming out because it is trying to reproduce frequencies the sub can't deal with no matter what, and you don't have a subsonic filter in place. Although with the EP2500, I would've thought that's not a problem.


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## Darren (Apr 20, 2006)

Here are my filters:

25Hz 20/60 -4
32Hz 6/60 -7
50Hz 10/60 +7
63Hz 4/60 +12
80Hz 21/60 -10
100Hz 13/60 -12


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## bobgpsr (Apr 20, 2006)

I don't think you should go over +3 at 50 & 63 Hz. Nulls really suck don't they.  

Bob


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## Guest (Jul 28, 2006)

Darren, 

I was wondering what that thunder was coming from Washington...got all the way to the Oregon coast. :scratchchin: (Not to ruin your fun, but 105 db is where hearing damage begins to be an issue.)

I'm not completely certain I understand your setup, but it seems you have your amp gain set way too high. Added to the large PEQ db boost, your clipping is quite understandable. (PEQ performs better on peaks than nulls. I agree with the poster who said limit null gain to +3db, or perhaps even 2db.)

Finally, LFE, low frequency bass, and receiver bass crossover are all different things. Is it possible that your source (dvd player?) settings may be contributing to your problems? You probably know what I'm about to say, but I'm new here, and I'm not clear on your setup or background. So what the ****, ....LFE is the .1 in 5.1 (6.1 or 7.1) and is a discrete signal generated by DD sources. Low frequency bass is all other bass (frequently confused with LFE) that your receiver is set to tell the sub to play and can include VERY low bass, and the receiver xover is the floor at which your main's low end frequency will roll off. What is your receiver bass xover set to? (And what are your main speakers?) Is the receiver bass set to sub or mains or both? And I'd guess your IB doesn't have a separate xover controlling it...is that true? With more information, perhaps we can troubleshoot your problem a bit better.

If you've been through all these things already, feel free to tell me to take a hike and go back to catching up with all the threads, lol.

Good cheer.


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## Darren (Apr 20, 2006)

I'll try to answer all them questions 

I'm using the LFE out and my reciever is crossed over at 80Hz. My mains are GR-Research AV2's which go down to about 55Hz when running full range but of course with the AV receiver they are crossed over at 80Hz. All set to small, subwoofer=yes.

Yup, I know about hearing damage and we listen at much lower volumes... we listen to home theater a bit higher...probably around 100db when the effects kick in. I'm currently testing and trying to set my system up for the worst possible scenario so I don't end up toasting my subwoofer. 

I think I'm getting pretty close. With the filter adjustments I think I'll be fine. I just don't really know how to approach room treatments to take care of my nulls. I'd love to find a reference on room treatment that is written in plain language


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## Josuah (Apr 26, 2006)

Nulls will either be due to placement (move your subwoofer, or use two subwoofers that are not colocated to help deal with it even better) or room modes relative to your listening position. So you can either move your subs, your seat, or use room treatments to prevent those reflections from creating the standing wave that is causing in de-constructive interference.

But at 63Hz, you'd need heavy room treatments. Really thick and dense rigid fiberglass or mineral wool. You're better off playing around with subwoofer placement a bit first. I have a large open room, so room modes aren't an issue for me execpt at ~70Hz. Which I think is the ceiling height.


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## Guest (Jul 28, 2006)

Darren said:


> I'll try to answer all them questions
> 
> I'd love to find a reference on room treatment that is written in plain language


Your setup looks all a-okay. 

For a treatment on room treatments :jiggy: ,have you seen this? ---> http://www.ethanwiner.com/acoustics.html

He's pretty straightforward.


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## Josuah (Apr 26, 2006)

Oh, plain language for room treatments. The thicker the rigid fiberglass or mineral wool, the better it absorbs deep frequencies. The greater the amount of airspace between the sheet and the wall behind it, the better it absorbs deep frequencies. But sound goes around things, so I think you want to make sure the air behind and the air in front can't touch each other. That's the basis for a panel trap, I believe. Refer to Ethan Winer's web site for details on a panel trap. I also built one and have pics of the construction up at http://www.wesman.net/~wesley/myphotos/?gid=3.

Placement of room treatments if fairly simple. All six surfaces of the room, wherever sound will reflect from a speaker to your listening position. Simple reflection using a mirror is a common way to locate those positions. If you can place a mirror somewhere and see the speaker from your seat, then that's a first reflection point. If you do the same thing with two mirrors, on opposite surfaces, that's a second reflection point but not really as much of a concern in most cases. Those reflection points is where you place a room treatment.

People also put bass traps into the eight corner-points of a room, and/or the four corner areas. These can be panel traps or thick, dense panels.

So, I have a large panel trap on my back wall, no room treatments on my front wall except for heavy velvet curtains (they made a difference in sound being on the front wall, although not as good as if I placed room treatments), and heavy velvet curtains on the side where my first reflection points would be if I had walls there. The floor is a rug, and the ottoman helps a little too. The ceiling has some light fabric across it, although I am wondering if I should put treatments up there too. I have a little dip in the ceiling that kind of prevents a first reflection point up there. I do have treatments on my ceiling for the surrounds. No corner treatments as I don't really have corners.


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## Darren (Apr 20, 2006)

Thanks for the explanation. Moving the subwoofer is not possible. It's an IB and large room treatments aren't either. It's our family room  Looks like I'm probably stuck with the null


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## Guest (Jul 28, 2006)

Darren said:


> Thanks for the explanation. Moving the subwoofer is not possible. It's an IB and large room treatments aren't either. It's our family room  Looks like I'm probably stuck with the null


Yep, that's the problem many of us face with multi-purpose (and WAF controlled) rooms. 

Darren, don't give up yet! How about a second (box) subwoofer? The second one can help ameliorate the null with careful positioning and crossover settings.


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## Sonnie (Apr 11, 2006)

IMO... you'll be wasting your time trying to tame a null at 50-60hz with room treatments... it's a tough calling.

I think your best bet is what Josuah suggested above... :spend: :spend: :spend:

If you were to duplicate those 4 SS's in the rear of you room you would probably solve all your problems. You might not have much of a house left, but who cares about that.


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## Chrisbee (Apr 20, 2006)

rjbudz said:


> Yep, that's the problem many of us face with multi-purpose (and WAF controlled) rooms.
> 
> Darren, don't give up yet! How about a second (box) subwoofer? The second one can help ameliorate the null with careful positioning and crossover settings.


One doesn't add a box sub to an IB unless you want to throw away all the advantages of the IB. (Very low distortion, micro-detail, etc) 
Not so much thowing the baby out with bathwater as throwing a bucket of mud into the bathwater with the baby.


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## Chrisbee (Apr 20, 2006)

Josuah said:


> Yeah, +12dB filter is extremely bad. Only do cuts, and then boost the overall volume. You may also be bottoming out because it is trying to reproduce frequencies the sub can't deal with no matter what, and you don't have a subsonic filter in place. Although with the EP2500, I would've thought that's not a problem.


I'm using a maxium boost filter at 20Hz.  

If I ever get my EP2500 clipping lights to come on I'll hold a big party. 

Surely having a broad boost filter and then dragging the surrounding humps down is the same as a very mild boost at the nominal frequency?

A narrow filter might be another matter, of course, as the amp can see it and dump a lot of power into it.


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## Ed Mullen (Jul 28, 2006)

Hi Darren:

There is a difference between the subwoofer channel level and the LFE trim (attenuation) control. 

If your speakers are set to small, then the AVR will send the redirected bass from all speaker channels, and the LFE channel (on DD/DTS sources), to the subwoofer pre-out jack. 

The subwoofer channel level will adjust the overall level of the signal going to the subwoofer. The LFE channel trim control will reduce the level of the LFE channel (the .1 in 5.1) and typically has a range of 0 (unattenuated) to -10.

Unless you are overloading your subwoofer or amp, the intended and correct setting for the LFE channel is 0 in your AVR. This article is also good reading.

http://www.hometheaterhifi.com/volume_7_2/feature-article-misunderstood-lfe-channel-april-2000.html

Your subwoofer channel level will of course vary depending on the specifics of your calibration, but typically setting it to around -5 (on a scale of -10 to +10) will help prevent pre-out clipping and will also allow some upward and downward adjustability. Calibrate the overall subwoofer level (relative to that of the other speakers) by adjusting the gain at your subwoofer amp. 

Unless you are actually measuring the in-room FR of the speakers and subwoofer combined (and using that information for setting the sub level), I like Avia for subwoofer calibration because it relies on redirected bass and the speaker channel in question will also contribute to the sub calibration tone.

Regards,

Ed


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## Sonnie (Apr 11, 2006)

Hi Ed.... welcome to the Shack! Good to see ya around.

With the BFD in the chain and its input level needing to be set properly, I'm wondering how much room we have to adjust the sub pre-out levels on the pre-pro/receiver? 

I have this same amp and sub setup, but haven't put it all together just yet.



Chris... how is your input levels looking on your BFD? Have you noticed?



> 50Hz 10/60 +7
> 63Hz 4/60 +12


This is a fairly wide and large boost when combined... it might be interesting to see what happens if you took these out.


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## Darren (Apr 20, 2006)

Right now I have my subwoofer set at -10 and the other speakers at or around -6 in the Subwoofer Level settings. I'm not sure of the LFE setting...I'll double check tonigh. I could of course up all of my settings so the subwoofer is at zero but I didn't think that would really make any difference. I can give it a whirl though 

I'm gonig dial those filters way back, I'll probably leave them in place but will cut them back to +4 or so each... not sure if that is a great idea to leave them in or not but it should take care of my problem. I could also change my crossover to 60Hz which would fill that null by directing the 60Hz bass to my mains but I'll lose a small bit of frequency range in that area since my mains only go down to 55hz then roll off quickly.

I'll read up on the LFE calibration as well.

Oh, there is no bottoming out... the drivers have lots of headroom. It's just the amp clipping and it looks like we are sneaking up on the reason why.


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## Ed Mullen (Jul 28, 2006)

Sonnie said:


> Hi Ed.... welcome to the Shack! Good to see ya around.


Thanks, Sonnie - you have a nice forum, and it's well moderated. And there is a good group of guys hanging out here. 



Darren said:


> Right now I have my subwoofer set at -10 and the other speakers at or around -6, I could of course up all of my settings so the subwoofer is at zero but I didn't think that would really make any difference. I can give it a whirl though


Well this is the crux of the discussion IMO. If you are truly referring to the subwoofer channel level, then having it at -10 is no problem at all - that's simply the setting where your system is properly calibrated. And Sonnie makes a good point; the BFD is a touchy sonofagun to set-up properly with respect to I/O levels and not clipping the inputs. 

If OTOH you are/were referring to the LFE channel attenuation control (which is not the same as the subwoofer channel level), then a setting of -10 (on a scale of 0 to -10) is not appropriate and will result in significant underrepresentation of the LFE channel on DD/DTS sources, relative to that of the redirected bass.


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## Darren (Apr 20, 2006)

I'm referring to the Subwoofer Level...not the LFE . Sorry for the confusion. I haven't looked at the LFE setting for a long time so I'll have to double check that, my memory tells me it is at 0.


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## Guest (Jul 28, 2006)

Chrisbee said:


> One doesn't add a box sub to an IB unless you want to throw away all the advantages of the IB. (Very low distortion, micro-detail, etc)
> Not so much thowing the baby out with bathwater as throwing a bucket of mud into the bathwater with the baby.


...or throwing a bucket of mud into a void...when you want _something_? But your point is well taken, thanks for the education. I'm not at all familiar with the sounds of IB's.


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## Guest (Jul 28, 2006)

Ed Mullen said:


> If OTOH you are/were referring to the LFE channel attenuation control (which is not the same as the subwoofer channel level), then a setting of -10 (on a scale of 0 to -10) is not appropriate and will result in significant underrepresentation of the LFE channel on DD/DTS sources, relative to that of the redirected bass.


Warm greetings to you, Ed. Your expertise is welcomed.

This is what I was trying to get at earlier, but he hinted that his AVR gain was controlling the redirected bass. 

If that's a legit null, do you have any recommendations?


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## Darren (Apr 20, 2006)

rjbudz said:


> Your expertise is warmly welcomed, Ed.
> 
> This is what I was trying to get at earlier, but he hinted that his AVR gain was controlling the redirected bass.
> 
> If that's a legit null, do you have any recommendations?


 
Yeah, I was a bit confused earlier on but am straightened out now. My LFE should be set at 0, my subwoofer level is at -10. 

It is a legit null between 50 and 65Hz. I'd love to get rid of it or minimize it without the huge boost I currently have because it creates a monster peak in other areas of the room. 

I'm considering living with the null and reducing my boost to +5 or switching my crossover to 60hz so the mains are reproducing down to 55Hz (they roll off sharply after 55Hz) but I'll have a small hole in my response. We'll soon be getting an additional couch on the right wall which is currently bare except for a large bookshelf. That might help a little eh?

One thing I need to do is take new measurement with the new drivers I have... the response should be quite similar to the previous drivers though so I don't expect much of a change in that null.


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## Guest (Jul 28, 2006)

Darren said:


> I'm considering living with the null and reducing my boost to +5 or switching my crossover to 60hz so the mains are reproducing down to 55Hz (they roll off sharply after 55Hz) but I'll have a small hole in my response. We'll soon be getting an additional couch on the right wall which is currently bare except for a large bookshelf. That might help a little eh?.


The couch should definitely help. Out of curiosity, Darren, what is the size and shape of your room, including openings to other spaces, and at what position is the IB?


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## Darren (Apr 20, 2006)

You can see lots of pics at http://www.garagehobbies.com/ib.aspx?Section=Room you can browse the other sections of the IB install with the links in the left menu...

The room is nearly square (bad) at 16' wide by 18' deep with a tray ceiling that goes up to 10' tall. I think I calculated the room to be about 3,200 cubic feet not accounting for the open area to the rest of the house. The rear wall is half open to the rest of the house and the front wall has a brick fireplace with plasma over it. Each side has book shelves and the left wall is all windows, right wall is bare. Couch on left wall in front of windows, love seat in listening position 15' from front. Coffee table in center of room. The IB is in the ceiling just above my plasma directly between the mains.

Here are a couple pics of the back wall open to the rest of the house that aren't on my website. What you see is the large hallway to the kitchen which is open to the rest of the house to the left of the kitchen and up stairs in the open stairwell.

These are old pics so the side wall with the bookshelves are what are going, the old box sub is the one I sold and the speakers are no longer at that position. The pictures on my website are more current to the system I have now.


Looking at the back wall void, the love seat is the listening position


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## Chrisbee (Apr 20, 2006)

Sonnie said:


> Chris... how is your input levels looking on your BFD? Have you noticed?
> 
> This is a fairly wide and large boost when combined... it might be interesting to see what happens if you took these out.


Nope. Haven't seen any obvious change on the BFD lights.

Without the BFD my IB is a 120+dB killer in the 40-70Hz range.

But I wanted the VLF house-shaking effects I'm used to from the SVS.

It still doesn't do exactly what the SVS did but it goes much, much louder and is night and day clearer. 

There's no going back now. I just want four more IB drivers for greater dynamic range. :T


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## Guest (Jul 28, 2006)

Darren said:


> Looking at the back wall void, the love seat is the listening position



Thanks, Darren. Is it possible to move your listening position? You may be able to dodge some of this nasty oblique mode by moving away from that gaping opening/hallway into the kitchen. It could be useful to measure your room resonances from different potential listening positions.


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## Darren (Apr 20, 2006)

Well, that's pretty much the only option. It is centered left to right and just forward of the back of the room. Moving it left or right would mess up my image. I could move it forward a short distance. The love seat is slightly to the left of center but I sit in the right side which is perfectly centered.

I've thought of installing a nice heavy curtain/drapery that could slide across for listenging but I wasn't sure if it would provide any benefit.


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## Guest (Jul 28, 2006)

Darren said:


> Well, that's pretty much the only option. It is centered left to right and just forward of the back of the room. Moving it left or right would mess up my image. I could move it forward a short distance. The love seat is slightly to the left of center but I sit in the right side which is perfectly centered..


My apologies again, if I'm asking you to repeat information available on other threads (since I'm pretty new, here,:yikes: ). What did you use to measure the in-room FR of the IB? TrueRTA? Avia disc and spl meter? Going by what the BFD PEQ'ed??? 

If you have listening position options, it should take but a few moments to run sweeps at those positions, especially with the TrueRTA.


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## Darren (Apr 20, 2006)

I use the Room EQ Wizard software and measured full sweeps. No problem on the other thread info...not easy to keep up with all the dicussions 

I tried using the AVIA disk and hurled it across the room. It's a terrible piece of [email protected]#$%^. I figured it out but refuse to use it on the basis that it is the worst UI on earth... I should have bought DVE. Sorry for the rant, it snuck up on me  Anyway, my audio is all done with the Room EQ Wizard software and full sweeps. I will be taking new measurement but am not sure taking measurements in other locations will do much good since I will only listen in the sweet spot.


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## Chrisbee (Apr 20, 2006)

rjbudz said:


> My apologies again, if I'm asking you to repeat information available on other threads (since I'm pretty new, here,:yikes: ). What did you use to measure the in-room FR of the IB? TrueRTA? Avia disc and spl meter? Going by what the BFD PEQ'ed???
> 
> If you have listening position options, it should take but a few moments to run sweeps at those positions, especially with the TrueRTA.


Then you haven't heard of REW software? 

Check out the REW Forum here at the Shack.


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## Guest (Jul 28, 2006)

Chrisbee said:


> Then you haven't heard of REW software?
> 
> Check out the REW Forum here at the Shack.


It is indeed new to me! Many thanks for the heads-up...I'll go explorin'. :T


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## Ed Mullen (Jul 28, 2006)

Sounds like you've got the bass management straight - that's good news. 

Recommendations for nulls? Bass traps - the bigger the better. Check GIK Acoustics for its new triple stacker (three 2" 703s) - wow, that's some bass trap.


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## Darren (Apr 20, 2006)

Ed Mullen said:


> Sounds like you've got the bass management straight - that's good news.
> 
> Recommendations for nulls? Bass traps - the bigger the better. Check GIK Acoustics for its new triple stacker (three 2" 703s) - wow, that's some bass trap.


I wish I had that option. It would clash with my wife's style unfortunately. My theater has to play well with my wifes family room


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## Chrisbee (Apr 20, 2006)

Darren

Your room is so full of holes I doubt it knows what size it is. 

Are you sure there isn't a resonant surface sitting at the bottom of your trough?

Have you tried playing a sinewave centred on the trough and see if something isn't humming away cheerfully to itself?


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## Darren (Apr 20, 2006)

Haven't tried that yet


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## Josuah (Apr 26, 2006)

I think lowering the crossover and seeing if your mains can fill up that void is a good choice. Using the SMS-1, I found that I can address some of my ~70Hz null but setting my crossover at 60Hz. At a 50Hz or 70Hz crossover setting, the problem comes back. The other thing to check is phase? If I have my crossover at 60Hz, then reverse my sub phase using the SMS-1, the hole drops dramatically. Plus, you can move your mains a little bit too.


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## Darren (Apr 20, 2006)

Josuah said:


> I think lowering the crossover and seeing if your mains can fill up that void is a good choice. Using the SMS-1, I found that I can address some of my ~70Hz null but setting my crossover at 60Hz. At a 50Hz or 70Hz crossover setting, the problem comes back. The other thing to check is phase? If I have my crossover at 60Hz, then reverse my sub phase using the SMS-1, the hole drops dramatically. Plus, you can move your mains a little bit too.


I may give it a whirl for fun but I believe I'll have a hole in my response if I do indeed lower the crossover point to 60Hz but I might be ok.


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