[Mikeyb]

I have been moving speakers around, and after putting my Panoramas in their permanent position (not quite ideal - about 6ft apart and approx. 2.5ft from side and rear walls, and Titan II in the front right corner), I used the ACI-supplied subwoofer setup CD to measure system response from 20Hz to 120Hz.

Processor set with all speakers small and 80Hz crossover.  Titan's crossover A turned all the way up and crossover B turned almost all the way down (35hz).  Phase set to zero (I notice no difference when adjusting phase), and level much closer to minimum than the half way point to maximum.  Using line level inputs.

Running the test tones and setting the "control" frequency of 60Hz to 70db, I got horrible results above and below 60Hz:  had steady increase in decibal level peeking at +14db at 90Hz, and going the other way, +21db at 35Hz.  There were no dips below 70db.

I played around some more, plugged the ports on the Panoramas, and recalibrated using Avia (previously, I always calibrated with the processor test tones).  I got much better results above 60Hz, but I still had a peek of +12db at 90Hz, and the response below 60Hz was just about identical to the previous (ugly) results.  I kept adjusting, moving the sub several inches, and nothing I did made the results vary below 60Hz.  The results were nearly identical every time.

The one thing I did not do was play with the crossover settings in the processor.  Any suggestions on what I can do to improve the response (especially below 60hz)?

One other question:  What is the cutoff point on the Panoramas when the ports are plugged?  Should I set the crossover to or about what this cutoff point is?  I am able to adjust the crossover for the main speakers separate from the others.

Soundwise, I only have objections with really low bass - it (sometimes)causes everything in the room to rattle - the tv, the window, pictures, and sometimes items in the kitchen, which is behind the viewing room!

Thanks for any much needed help!  Any suggestions are welcome...

[circularduck]

I think the problem lies with your crossover setting on the sub.  Each of the Titan crossovers is a 12 dB/octave filter (I believe).  At first I would try just turning both crossovers all the way up, and see what the result is.  Then, if you are having problems around the reciever crossover point (80 Hz), try setting one of the Titan crossovers to 80.  This will help transition the sound from the Panoramas to the Titan faster (it gets the main speakers "out of the way" faster).  If you would like it to have an even steeper transition, you would set both crossovers to 80.  Then you can make fine adjustments around that point to try and eliminate problems around the crossover point.

That is my understanding of your problem anyway.  It may or may not fix it, but do think you are not using the crossovers correctly on the Titan.

[kendrid]

If you continue to have room problems, look into using a BFD (Behringer Feedback destroyer).  It is a 24 band parametric EQ that a lot of people use to EQ their subs.  There is a free application that goes wtih the BFD that will automatically measure your room and 'fix' peaks (RS SPL meter required).

BFDs go for around $100.

Here is the manual setup guide:
http://www.snapbug.ws/bfd.htm

EQ application and help thread:
http://www.avsforum.com/avs-vb/showthread.php?t=529224&page=1&pp=30

[Mikeyb]

Thanks for the suggestions!

Before I run out and try the BFD (I might pull all my hair out figuring that thing out), what do you think of this strategy:

1.  Set both Titan crossovers to max and recalibrate using Avia

2.  Test/chart the Titan sub with no other speakers on

3.  If I get bad results, try adjusting the crossovers (either 1 or both)

4.  If can't improve results, try moving the sub (not many options here though).

5.  If still can't improve results, try something more drastic (RDES or BFD)

[kendrid]

Thanks for the suggestions!

Before I run out and try the BFD (I might pull all my hair out figuring that thing out), what do you think of this strategy:

1.  Set both Titan crossovers to max and recalibrate using Avia

2.  Test/chart the Titan sub with no other speakers on

3.  If I get bad results, try adjusting the crossovers (either 1 or both)

4.  If can't improve results, try moving the sub (not many options here though).

5.  If still can't improve results, try something more drastic (RDES or BFD)

That sounds like the proper route to go.  If you can't move your subs and can't get a good response, a BFD (or something similar) is about the only choice you have.  Hopefully changing the crossover and levels will fix your issues.

[Mikeyb]

Well, I am having almost no success in improving measured response.

I have set the Titan crossovers to their max settings, recalibrated, measured bass response with only the subwoofer powered (the amp driving the speakers was turned off), and the below 60Hz response still booms.....to ~+20db at 35Hz or so.  I tried moving the sub up to 2 feet out into the room (from the back wall but still along the side wall), and still the response booms from below 60Hz.  I have played with the subs crossovers...too many scenarios to recall, and still no success whatsoever.

For reference, here's the way I have been testing:
Using the ACI subwoofer setup CD, I play the 60Hz warble tone and set volume to 70db (using db meter) as the reference.   I do this after every change in setup.  I then play the other tones, 1st going up from 60Hz then down from 60Hz.  I am not as concerned with the response above 60Hz - it's not that bad.

What I find strange is that at 60Hz I can set volume to 70db, but just dropping to the 55Hz tone, in every possible scenario, output jumps at least 7db and usually 10db or so.  Dropping to 50Hz, output jumps again, and then continuing down, output climbs to a max of ~+20db (corrected value) at 35hz.

Very frustrating!

It seems I have very serious peeks all the way down the scale below 60Hz.  Will a BFD or possibly the new RDES help flatten this kind of response and make an improvement that is noticeable (in actual movie and music listening)?

For now, I have calibrated the system so that according to Avia, it is dead on flat.  I then reduced the sub output by -3db in the processor speaker settings hoping some of the (room mode) boom will be reduced.

The system sounds (and always has) awefully good, but I wonder how much clearer or more impactful it might sound with better bass response.  What's being covered up because bass below 60Hz is playing twice as loud or more than much of the rest of the system?

One other thought:  In looking at my original graph, it looks like the target db level should be 80db and that I have a dip from 60Hz to 80Hz and a peek at 35 - 40Hz.  It doesn't look near as bad looking at it this way...Hmmm...

[MaxCast]

What size is your room?
It may be useful to readers if you post your readings from 20 to 100Hz.
Try turning your sub down so the spike isn't so bad.  You may be able to play with the xo range to take care of a dip around the 80Hz high pass.

Have you tried you speakers set to large and using the lowest xo setting on the sub?  I find it interesting running tones with just the sub and with just the speakers.  I will help when you run them both together.

Have you tried the sub in a different location, just to see the readings?

[Mikeyb]

The room is a true rectangle:  11' 4" wide by 27' deep.  The room is a kitchen and family room combo, with the TV and front speakers on one of the 11' walls.  The kitchen is directly opposite the TV and is about 10' deep, so that makes the family room portion about 11' by 17' (kitchen 11' by 10').  There is only a breakfast bar that separates the two rooms.  The only entry into the room is a typical doorway along one 27' wall between the kitchen and family room.  The other 27' wall is the back of the house and is mostly windows.

Here are readings that are representative of just about all my measurements (reference is 70db at 60Hz measured, and db is expressed in compensated values rounded):

Hz  20  25  30  35  40  45  50  55  60  65  70  75  80  90  100
db  88  89  90  92  89  86  83  80  71  71  73  75  77  82  80

I have not attempted running the system with the speakers set to large, but in testing only the sub, I did turn both crossovers all the way down, then set the reference 60Hz tone to 70Hz output and got very similar results to my other poor results (excessive boom below 60hz).

I am very limited in where I can place the sub, so I have not tried moving it far from the corner it's in now (a couple feet at most).

Thanks for all suggestions!

[MaxCast]

What are the xo points on the processor?  slopes?  model?

Usually when using the xo in a processor you turn the subs xo up (to a higher xo point, like 100) so it gets out of the way.

Does this sub have a xo bypass?

I would set the sub level so the 30 Hz region is close to the same level as your mains in the 80 and above region.  Then try playing with the xo and see what type of integration you get in between.

[Sonnie Parker]

Mikeyb...

You need a BFD no doubt and it's not that hard to figure out how to use it.

First things first though... if you don't have them, download the 1/6 octave tones and MS Excel Workbook from the GUIDE page.  The tones you are using are not going to work properly.  Take your 1/6 octave measurements and insert the levels into the GUIDE.  Post a pic of your graph here and let's look at it.

There is also the Room EQ Wizard that will take your measurements, figure out what filters you need and then send them to the BFD via a MIDI cable... making the setting of filters on the BFD so much easier.

[ScottMayo]

Have you treated the room? Never mind the electronics - that's for fine tuning. At a guess, you ned some serious bass trapping. *Then* go after the electronics.

[Sonnie Parker]

Hz 20 25 30 35 40 45 50 55 60 65 70 75 80 90 100
db 88 89 90 92 89 86 83 80 71 71 73 75 77 82 80

While these are not really the right choice of measured frequencies, they do tell us somewhat of a story... 1/6 octave measurements will give us a more accurate story.  Keep in mind that correctin values are only available for 1/6 octave frequencies so your measurements are not going to be as accurate when trying to estimate correction values for those frequencies not already calculated.  Correction values:



None the less, there is nothing here that needs more than a little fine tuning and nothing that the BFD at a 100 bucks can't very easily tame.

1/6 octaves may change these but the pattern indicates somewhat of a desired house curve, with a little more drop between 60-75hz than we'd like.  

Trapping 20-35hz bass is no easy task either, right?  Plus it can get quite expensive.  I don't think 100 bucks will even begin to touch acoustical treatments unless someones evented something I haven't heard of.

I'd stick with the electronics on the low end and acoustics on the upper end (for first and second order reflections, etc. if needed).[/img]