Someone please help me with my sub localization issues :( - AVS Forum
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post #1 of 58 Old 04-05-2011, 12:07 AM - Thread Starter
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Hello masters of audio, I come to you with my sub localization problem, it's freakin killing me! I will start off with a list of the three main pieces of gear and placement drawing...

Marantz SR5003
Foster plate amp
Table Tuba subwoofer (folded horn)



I have set the system up with Audessey and everything sounds good except for being able to localize the sub and not just because I know it's near me. I litterally feel bass deaf in my left ear most of the time. Even with test tones from 30hz to 80hz, I can hear them on my right. Once in a while in a movie I will hear a nice thump or rumble that feels like it's coming from everywhere or the ground in front, but most of the time, all of the bass is heard on the right.

Some tell me that it's because I'm either hearing distortion or frequencies above 80hz and I've also been told that it's just the way my room is.

Note: I cannot change where the sub is, it's made to fit in that corner. At it's current position vs other positions I've tried in the room, the bass is the strongest/loudest where it is now.

Feel free to ask questions that may help you in giving me some things to try
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post #2 of 58 Old 04-05-2011, 12:31 AM
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Have you tried the bass crawl? (I'm assuming this is what netted you that corner?)
Have you tried playing with levels/crossover settings/etc yourself, ignoring what Audessey did (or running with the Audessey adjustments disabled?)?
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post #3 of 58 Old 04-05-2011, 04:33 AM - Thread Starter
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I did not do the crawl test for a few reasons. One being the size of the cab limited me to pretty much one feasible placement option. Two being it was recommended that it be placed in a corner to utilize the wall and floor reflections to add output. Three being that I hear a lot of people put their subs in the rear of the room without any problems. Seemed like a win win situation =)

As for Audyssey, I let it set everything up initially but since then have played with a few basic settings such as adjusting the LPF/HPF crossover point on receiver between 60hz and 80hz, neither had much effect. Adjusting amp filter between the same range, still no real effect and sub level gain as well. Once Audyssey set my speakers at the same db level, I checked the volume output with my db meter and they were all the same. I even lowered my sub level down about 6db and it was still just as locateable, just with decreased volume.

In a few, I'm going too see if phase has any effect and maybe adjust the "distance" for the subwoofer. Then ill turn off Audyssey and play with a few things then.

I never played hardcore with settings because I didn't think small differences would magically make my problem go away :-/
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post #4 of 58 Old 04-05-2011, 06:01 AM
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Quote:
Originally Posted by Digital_Chris View Post

Two being it was recommended that it be placed in a corner to utilize the wall and floor reflections to add output.

Maximum output, yes, but also it is the site where it will maximally excite all the primary modes of the room. Your room seems to have dimensions scaled badly especially if the ceiling height is 8'. All this leads to sharp nulls and peaks in the spatial distribution and, I suspect, that accounts for your left/right differences. If you insist on keeping the sub in the corner, you need lots of bass traps and/or good subwoofer EQ. What version of Audyssey are you using?

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post #5 of 58 Old 04-05-2011, 06:20 AM
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I too have significant issues with localization via pressurization asymmetry @ LF. I experimented extensively with near-field subs, much to my delight, nothing like it for an individual that's spent there life around live sound (tactile immediacy, and ruler flat response). However, I gave up due to traffic flow logistics in my non-dedicated space.

I found the only way I could achieve decent integration, was to create symmetry. Either directly in front, behind, on in between pairs. The pressure differential was way too disconcerting otherwise.

What's this mean for you? Major surgery if you wish to address it. Either move your seating forward, and place the sub directly behind the primary LP, or create another sub and experiment with placement and phase adjustment until your satisfied. Now the first suggestion, combined with some rear wall treatment, would seem like a win/win. I gets you off that rear boundary (never good), and allows for symmetry wrt LF, and some measure of acoustic treatment for the rear wall.

We skipped the obvious movement of the sub to the front, as I guess it's a no go.


Good luck


edit; how about a coffee table sub?

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post #6 of 58 Old 04-05-2011, 03:17 PM - Thread Starter
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Thank you guys for your ideas. Bass traps are probably not going to happen just because I just don't want to spend that much time and effort in making this room perfect but I do appreciate your ideas. I wouldn't mind tinkering with EQ if it's cheap and not so hard to do.

I have tried using the sub as a coffee table but it doesn't sound well at all. Basically, if I can't "fix" my issue with tuning, then I will just live with it. The only movie that I have played so far where the bass was WICKED directional was Matrix Reloded. A few others I have played scenes from were more balanced, I also lowered my sub level 12db in the receiver which resulted in an actual volume difference of about 10db. The bass is still there and seems to be at the correct volume, just not sure why Audyssey sets it what seems to be too loud.

Oh well, any more ideas, feel free to shout them out but I don't want to make any large changes to the room, it's not that important since my dedicated theater room will be downstairs.
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post #7 of 58 Old 04-05-2011, 03:43 PM
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Quote:
Originally Posted by Digital_Chris View Post

Thank you guys for your ideas. Bass traps are probably not going to happen just because I just don't want to spend that much time and effort in making this room perfect but I do appreciate your ideas. I wouldn't mind tinkering with EQ if it's cheap and not so hard to do.

I have tried using the sub as a coffee table but it doesn't sound well at all. Basically, if I can't "fix" my issue with tuning, then I will just live with it. The only movie that I have played so far where the bass was WICKED directional was Matrix Reloded. A few others I have played scenes from were more balanced, I also lowered my sub level 12db in the receiver which resulted in an actual volume difference of about 10db. The bass is still there and seems to be at the correct volume, just not sure why Audyssey sets it what seems to be too loud.

So, again, what version of Audyssey do you have and how did you run it (# and location of positions, mic support, etc.)

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post #8 of 58 Old 04-05-2011, 07:28 PM - Thread Starter
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Sorry Kal, I forgot to mention that. I'm not sure what version of Audyssey I am running (maybe 1.1?). When I did the test, I did the 6 positions (rear 3 positions first and then the same but 2-3ft in front for the other 3) that they mentioned with the Audyssey mic
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post #9 of 58 Old 04-05-2011, 07:35 PM
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Quote:
Originally Posted by Digital_Chris View Post

Sorry Kal, I forgot to mention that. I'm not sure what version of Audyssey I am running (maybe 1.1?).

None such. What is the model of your AVR?

Quote:


When I did the test, I did the 6 positions (rear 3 positions first and then the same but 2-3ft in front for the other 3) that they mentioned with the Audyssey mic

MLP first, of course, using a mic-stand or tripod?

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post #10 of 58 Old 04-05-2011, 08:12 PM
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Quote:
Originally Posted by Digital_Chris View Post

I have tried using the sub as a coffee table but it doesn't sound well at all.

Was this tested with full MultEQ tuning? If not, the result is not certain.

Underscoring FOH's symmetry comment, I'd suggest putting the sub under the TV, but it looks too big--it would stick out into the room. But if not...

Ok, now for some "out of the box" thinking. Pull the sub out of the corner and split the sectional midwall and separate them 3'. Stick the sub between them, and put a sofa cushion on top. Free bass shaker, and a midwall location.
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post #11 of 58 Old 04-05-2011, 08:15 PM - Thread Starter
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Marantz SR5003

Yes, MLP first, the left of that and then right of that, followed by position in front of MLP, followed by left then right, all using tripod and just about the same height for each position.
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post #12 of 58 Old 04-05-2011, 08:21 PM - Thread Starter
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Quote:
Originally Posted by Roger Dressler View Post

Was this tested with full MultEQ tuning? If not, the result is not certain.

Underscoring FOH's symmetry comment, I'd suggest putting the sub under the TV, but it looks too big--it would stick out into the room. But if not...

Ok, now for some "out of the box" thinking. Pull the sub out of the corner and split the sectional midwall and separate them 3'. Stick the sub between them, and put a sofa cushion on top. Free bass shaker, and a midwall location.

I did not do an Audyssey test with the sub in the center of the room, I didn't think It would really make that much of a difference, enough for me to be pleasantly surprised anyway.

I made the Table Tuba into a 33" x 33" end table, so it would not fit anywhere near the TV. Also, that is an interesting idea, putting the sub between the sectional but I would be afraid that it would be too bassy even that much closer to the listening positions.. And then I would have to make my sectional ends look complete and find a cushion for the sub, just not what I feel like doing. But that is a good idea, I might have to do a mock up of that and see how it sounds
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post #13 of 58 Old 04-06-2011, 06:02 AM
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Without a frequency response graph the best we can do is guess at the problem and a solution. My guess is that you have too much energy at the upper end of the sub’s range, and the distance setting might be off. If that's the case, the right parametric EQ could address both problems.

Regards,
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post #14 of 58 Old 04-06-2011, 06:04 AM
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Have you measured the output of the sub? It may have resonances above 80hz which would be localizeable. You might try putting it next to your coffee table - where you have written "area rug" on your diagram. That way at least it would sound like coming from the center.

Everything I say here is my opinion. It is not my employers opinion, it is not my wife's opinion, it is not my neighbors opinion, it is My Opinion.
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post #15 of 58 Old 04-06-2011, 05:51 PM - Thread Starter
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I think I will try to get a graph made. I need to do some reading about REW and see if I can get it to work on my Mac. I would love to see what freq are coming out of that sub.

The latest thing I tried was putting a 30hz high pass FMOD inline which is working with the built in 29hz high pass inside the amp. It def took away some low end and toned everything down a bit but some content is still locatable.

I am also running my sub 10db cold compared to the rest of the speakers. Could this be because Audyssey set it higher thinking it was the correct volume when in reality it is hotter than it should be? Right now with it colder, it sounds more like I think it should, before it seemed too hot but my mind was thinking it was ok because it's the way the program set it. Weird.

Also, do you mean to put and keep the sub next to my coffee table? If so, I can't do that because the sub IS the size of the coffee table, a bit higher actually so it just wouldn't work. Thanks for the idea though
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post #16 of 58 Old 04-06-2011, 07:56 PM
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Quote:
Originally Posted by Digital_Chris View Post

Also, do you mean to put and keep the sub next to my coffee table? If so, I can't do that because the sub IS the size of the coffee table, a bit higher actually so it just wouldn't work. Thanks for the idea though

I would just try it to see if it helps. You don't have to keep it there, but it could provide you with some clues.

The only thing that I don't like about that location is that it appears to be in the center of the room where there will be a big dip at the fundamental frequency for your size room.

Greg
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post #17 of 58 Old 04-07-2011, 03:48 PM
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Quote:
Originally Posted by Gregory View Post


The only thing that I don't like about that location is that it appears to be in the center of the room where there will be a big dip at the fundamental frequency for your size room.

Greg

Typically, yes that is true. However listener proximity to a LF source results in a substantial smoothing of the response. Just as a close mic measurement of a sub minimizes the room's influence proportionally, so does near-field placement. I've achieved stunningly ruler flat response w/near-field subs, but I could never get absolute integration at the LCR crossover. Dealbreaker...but it was fun (ruler flat and +6db for every halving of distance=kick drums sounded like kick drums)


Good luck

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post #18 of 58 Old 04-09-2011, 10:00 PM
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i suck at this also.

but maybe you are like me and you went to way too many rock concerts back in the day and never wore ear plugs. i now have tinnitus b/c of this. i will never be able to hear music and movies the way they were meant to be heard. so now i pretty much just live with this and im happy with what i have now.

i recently upgraded to a new rx-a 800 yamaha aventage receiver and new klipsch sub to go with my good ole klipsch fronts. i had a great big klipsch center but gave it to my ex gf a long time ago and was never able to get it back. i bought a smaller klipch center long time ago and it was ok b/c i never had great new rec with hdmi/ 7.1 setup.

i now do so i upgraded to a bigger polk center sp b/c i could not afford a good klipsch center. i will soon have the extra speakers to make the 7.1 happen.

maybe one day soon i will get the 2nd sub to have 7.2 sound. have you thought of getting a 2nd sub and see how that might fix the problem?

sorry for messing up this discussion.

i feel for you dude

p.s. cum on feel the noize - quiet riot is on the radio now

roflmao
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post #19 of 58 Old 12-29-2011, 10:29 PM - Thread Starter
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Sorry to stir an old topic but I still have this problem.. granted I haven't done much to fix it but it just doesn't make sense why I can localize the sub, my only guess and as others have told me is that I have localizable frequencies coming out of the sub.. but why?

Especially during music, this is a huge problem... I understand that with poor subwoofer placement, I will have peaks and nulls throughout the room but why is it localizable? Anything I can provide for you to understand better or anything I can try?

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post #20 of 58 Old 12-30-2011, 05:23 AM
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What's your crossover? 80Hz and lower should not be localizable. Higher can be a problem.
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post #21 of 58 Old 12-30-2011, 05:46 AM
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Quote:
Originally Posted by Digital_Chris View Post

Sorry to stir an old topic but I still have this problem.. granted I haven't done much to fix it but it just doesn't make sense why I can localize the sub, my only guess and as others have told me is that I have localizable frequencies coming out of the sub.. but why?

Especially during music, this is a huge problem... I understand that with poor subwoofer placement, I will have peaks and nulls throughout the room but why is it localizable? Anything I can provide for you to understand better or anything I can try?


You really need to measure sub output, and not only level, but spectrum too. If you have too high THD, then you will hear these harmonics. Also try to set crossover frequency to something really low, like 40Hz (both in receiver and sub amp too).
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post #22 of 58 Old 12-30-2011, 06:26 AM
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My first suggestion would be rearanging everything (place the speakers and sub on the left or right hand wall in the diagram above), but I see you say that you can't move the sub.
Have you tried swapping the sectional for the TV/speakers location, leaving the sub basically where it is? This moves your position relative to the sub and you may move to a better/more enjoyable location.
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post #23 of 58 Old 12-30-2011, 09:21 AM
 
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Quote:
Originally Posted by Digital_Chris View Post

Sorry to stir an old topic but I still have this problem.. granted I haven't done much to fix it but it just doesn't make sense why I can localize the sub, my only guess and as others have told me is that I have localizable frequencies coming out of the sub.. but why?

There are several reasons, primarily because bass can be localizable. Here is a thread with several links to papers as to why.
Hard to say what might be the root cause(s) in your system. What is the sub low pass frequency? Does your sub cabinet emit resonances of it's own? Whats is you front speakers hi-pass? What front speakers do you have?

Quote:
Originally Posted by Digital_Chris View Post

Especially during music, this is a huge problem... I understand that with poor subwoofer placement, I will have peaks and nulls throughout the room but why is it localizable? Anything I can provide for you to understand better or anything I can try?

You could try a smaller, inexpensive (<$200) sub in the front left corner of the room, tucked between the TV stand and wall, low passed to match the mains. Then lower the low pass on the tuba horn woofer until you can't localize it....assuming this is possible.

cheers,

AJ
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post #24 of 58 Old 12-30-2011, 11:27 AM
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Quote:
Originally Posted by Wayne A. Pflughaupt View Post


Without a frequency response graph the best we can do is guess at the problem and a solution. My guess is that you have too much energy at the upper end of the sub's range, and the distance setting might be off. If that's the case, the right parametric EQ could address both problems.

Regards,
Wayne A. Pflughaupt




++ That. It seems the only solution that may yield results is EQ and damn the room response

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A DIY'er likes to talk about how little they spent and how good it sounds.

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post #25 of 58 Old 12-30-2011, 11:33 AM
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Quote:
Originally Posted by Digital_Chris View Post

Sorry to stir an old topic but I still have this problem.. granted I haven't done much to fix it but it just doesn't make sense why I can localize the sub, my only guess and as others have told me is that I have localizable frequencies coming out of the sub.. but why?

Especially during music, this is a huge problem... I understand that with poor subwoofer placement, I will have peaks and nulls throughout the room but why is it localizable? Anything I can provide for you to understand better or anything I can try?


People are giving you suggestion after suggestion. Crap or get off the pot (and stop posting/whining about it).

Hire a professional to try and EQ the sub response.

You can't / won't move equipement
You can't / won't add bass traps
You haven't EQ'd (that means read about REQ and purchased the requisite hardware).

The definition of insanity is trying the same thing over and over again and expecting different results.

If you can't/won't do any of the above then stop wasting everyone's time by posting about it.

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A DIY'er likes to talk about how little they spent and how good it sounds.

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post #26 of 58 Old 12-30-2011, 12:28 PM
 
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This thread is a bit painful to read.
Bass, contrary to what many assume, in a bounded space can be localizable, as has been correctly pointed out.

Unfortunately this thread vacillates between a focus on modal issues, which are concerned with localized regions of minimum and maximums, and a concern with EQ, but which have nothing to do with bass source localization; and localization issues reinforced due to asymmetrical close proximity.

The problem is not with the actual behavior, but with the erroneous assumption that bass cannot be localized that is presumed in the question itself. Unfortunately it is generally easier to modify one's assumptions and expectations than it is to redefine the rules of physics.

A solution has already been suggested above that addresses symmetry and the use of two sources to balance the current source of the signal or the movement of the sub to a more neutral position in the front of the room that allows the bass to correlate more closely with the full range sources - which has been summarily dismissed.

So, as much as the options may not suit the constraints of ones desires, the solutions are actually rather simple (in terms of understanding if not in implementation): Adjust the location of the sub and/or add a second sub as suggested; and while you are at it, address the additional modal issues (that have nothing to do with localization but allot to do with the quality of the bass within the space) through trapping and possibly EQ.


Edit;
I will add one other option that I am not positing as the most accurate solution but it does seem to be effective in such a situation, and that is to add a bass shaker to the seating. The visceral conduction tends to reinforce and dominate over the 'heard' portion of the low frequencies.

Now I am not going to claim this is the most analytically accurate LF, but then we are dealing with HT and I am not sure we really want to be sitting around debating whether the last sun you heard explode was "accurate" or not - especially as I am still waiting on an explanation as to why, in such movies, 2 spaceships always seem to be shown encountering each other precisely aligned in the same 90 degree 'up' orientation out of a possible 360 degrees despite there being no independent reference for such an alignment....other than we 'expect' it. Rather like we 'assume' that near field bass cannot be localized.
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post #27 of 58 Old 12-30-2011, 05:39 PM
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i am still waiting on an explanation as to why, in such movies, 2 spaceships always seem to be shown encountering each other precisely aligned in the same 90 degree 'up' orientation...


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post #28 of 58 Old 12-30-2011, 08:28 PM - Thread Starter
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Originally Posted by BIslander View Post

What's your crossover? 80Hz and lower should not be localizable. Higher can be a problem.

Both my receiver and amp x-over is set at 60hz, I can go a little lower on the sub amp but it doesn't make any difference.

Quote:
Originally Posted by ap1 View Post

You really need to measure sub output, and not only level, but spectrum too. If you have too high THD, then you will hear these harmonics. Also try to set crossover frequency to something really low, like 40Hz (both in receiver and sub amp too).

I will make up a couple of REW graphs and see what that shows, I'll post the results

Quote:
Originally Posted by John Schneider View Post

My first suggestion would be rearanging everything (place the speakers and sub on the left or right hand wall in the diagram above), but I see you say that you can't move the sub.
Have you tried swapping the sectional for the TV/speakers location, leaving the sub basically where it is? This moves your position relative to the sub and you may move to a better/more enjoyable location.

I'm not going to do surgery to the room, in fact, I don't want to move anything, just want to uderstand why some ppl say they can't locate their sub when it is right behind them, but I can, so easily too.

Sorry for sounding like I'm wining and not doing anything, it's just that most of the suggestions that have been given are to rearrange equipment, I already posted that it's not an option, I'm not taking this setup that seriously, it's just that it seems like I'm missing something.. when the guy who designed this cab told me that roughly 80hz and lower are non directional frequencies. His cab is right behind him and he can't tell it's there, this is why I'm just so confused.

I mentioned on another site that I did some playing around and placed the sub up front firing at the front wall corner and what a difference that has made, stronger bass and more evenly spread out, but, it doesn't tell me why I can localize it in the corner.

I'll go setup and take a few REW graphs, 20hz to 150hz or so, with all other speakers unplugged and see what that shows.

You didn't have to be so harsh Jin, I'm still learning..
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post #29 of 58 Old 12-30-2011, 08:48 PM
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Quote:
Originally Posted by Digital_Chris View Post

I'm not going to do surgery to the room, in fact, I don't want to move anything, just want to uderstand why some ppl say they can't locate their sub when it is right behind them, but I can, so easily too.

when the guy who designed this cab told me that roughly 80hz and lower are non directional frequencies. His cab is right behind him and he can't tell it's there, this is why I'm just so confused.

That guy and the other people most likely do not have the same room dimensions and layout that you have, or anything even close, so where other people have placed their subs is irrelevant unless you also take the other factors into consideration.. They may have done treatments and bass traps. They may not have the bass nulls that you have, or have compensated for them, whereas you have not. It's not just the sub placement that is causing the localizations.

It's hard to say exactly what is causing your localization without taking readings, but some of the posters here have given some pretty good suggestions.

Also, I don't know why you're disregarding bass traps, as they are hardly "major surgery." You're just hanging some panels that may do a lot of good. I don't think there will be some "magic bullet" setting adjustment for your situation.

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post #30 of 58 Old 12-30-2011, 09:13 PM - Thread Starter
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Sorry, when I said major surgery, I meant rearranging the room, and every time I hear bass trap, I think of huge corner traps, I always forget about the other types of bass trapping, sorry

Here is a basic graph from 30hz to 150hz that I took with REW, I don't know if it will tell you anything of importance but here it is. I'm new to REW as well so if you have any suggestions on how to take other readings, I'm all ears ...

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