# 1st Graph--how's it look?



## allredp (Feb 7, 2007)

Wow, after quite an odyssey, I've finally gotten my first graph! :bigsmile: 

I have an SVS PB12+/2 in a 27W x 15D x 8H room. It is corner-loaded in the top right about 15' from my main listening position. 

I haven't done any phase adjustment. I do have a BFD waiting to be employed--however, I don't see any REW filter assignments/suggestions under this measurement. 

Take a look and tell me what I can do to improve my sound! I can't thank everyone enough for aiding me in this mad obsession for audio nirvana...


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## brucek (Apr 11, 2006)

> I don't see any REW filter assignments/suggestions under this measurement.


I think you would benefit a lot by reading the REW HELP files. They explain all this section quite well.

I don't think you pressed the SET TARGET LEVEL button as shown the upper arrow in the attached jpg. You have a target level over 95dB. Before you do the Measurement and after you've executed the CALIBRATE SPL routine in REW you need to SET TARGET LEVEL.

You also won't have any peaks recommended if you're that far above the target line. 

Once the correct target level is set, to get peaks and filters you need to press FIND PEAKS, ASSIGN FILTERS, OPTIMIZE PK GAINS as shown by the bottom three arrows in the attachment.











It's a fairly good response though. You won't have much to do once you get the target levels set.

brucek


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## allredp (Feb 7, 2007)

Very helpful, Bruce.

I've now read ahead all of the REW Help files--I didn't know about the "set levels" etc. below the "measure" chapter!

So, I'm set to run some more measurements tomorrow and I'll get back with the results.

Thanks for all the help!

-- Phil

btw, doing this with a Media Center HTPC is actually quite a pain --I have to unplug the spdif digital coax to get the REW to recognize that analog imput, but then I have to unplug those and re-plug the others when I want to watch TV/DVD through the HTPC. I also am using my remote access to see the whole screen in REW on my non-monitor Sony TV--which then messes up the video settings for XP media center until I reset the HTPC.:dizzy: 

Oh well, its going to be worth the learning curve and the bother in the end once my SVS is properly filtered to reproduce in my room!:T


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## allredp (Feb 7, 2007)

Finally! I've set the target level, before measuring, and came up with the following graph. 









From what REW is saying, I need to input cuts at 37 and 45, right? Here's the graph:









I'm reading the BFD manual/help files and see that I need to know how wide to make the filter. According to REW I need to cut 37.2Hz back 6.3db, and also cut 45.5 back 4.0db, but how do I know how wide to make it?

Much thanks on the help--I'm thrilled to be this close!

Also, what to do about the 70Hz dip?

The Shack rocks...

-- Phil


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## terry j (Jul 31, 2006)

just click on optimise in the filter tasks tab. The program does it all for you!! no need to work things out for yourself. That, of course, is what makes it useful to me hahaha.

Don't know what sub you have or how capable it is, but if I want to bring something up I usually just try it with a few db of boost, then remeasure just to see if it responds. (just saw your sig, but have no knowledge of the sub) If it doesn't respond then leave it well alone. Comes up as a result, well then there are a number of camps ranging from NEVER boost to those who feel you can get away with around 6db of boost most times. I fall into the second camp, but only if it responds as expected as outlined above.


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## brucek (Apr 11, 2006)

> According to REW I need to cut 37.2Hz back 6.3db, and also cut 45.5 back 4.0db, but how do I know how wide to make it?


REW tells you what to enter into the BFD in the Filters panel. Its in the REW HELP files. Just enter the values into the BFD. Bandwidth is width.









If you want more of those peaks considered in the REW filter suggestions, simply Delete the Peak Table and lower the target line manually a few dB with the target setting thumbwheel and then press the Find Peaks, Assign Filters, Optimize again and you'll see the filters are a bit more aggressive in the corrected line.


brucek


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## allredp (Feb 7, 2007)

Bruce has the patience of Job, I tell you!:clap: :hail: 

Can't thank you enough for hanging in there with Mr. Low-tech...:R 

So, what is a reasonable drop in the target line? I was at 74.4 (I think) and now I've dropped it to 70--which results in the following additional peaks and suggested filters.

















Would you think these will make a difference in the sound quality? Are they enough to bother with, versus the original two at 37Hz and 45Hz?

With my SVS I've had tons of deep LFE, but I've wondered if I'm missing some "slam" and what you might call "tight" bass. 

Is my dip at 70db the cause of this? 

I'm leary of boosting anything and I don't want to corrupt the sound quality any more than absolutely necessary...

Thanks so much for the help!!!

--Phil


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## brucek (Apr 11, 2006)

> Would you think these will make a difference in the sound quality? Are they enough to bother with, versus the original two at 37Hz and 45Hz?


The new filters are far better. Use them - remove the old and add the new. I don't like to go too far above a -10dB cut and you haven't...



> Is my dip at 70db the cause of this?


Don't bother with the dip at 70 until you have loaded the 4 filters in the BFD, and then added your mains speakers and do a new measure (using the same method as before except the mains are now included with the sub).

Observe the area around the crossover (60Hz to 100Hz) and you may then need to adjust your subwoofer phase or distance setting to get rid of any new dip or peak. Sometimes that isn't effective and you need to tweak or add a filter to fix any new peak.

For your graphs, best to use the standard axis we normally use here of 45dB to 105dB vertical and 15hz to 200Hz horizontal. Just enter it into the Graph axis popup and invoke it any time after that if the axis changes on you....









Anyway, test those 4 new filters and then add the mains and retest..........

brucek


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## allredp (Feb 7, 2007)

:jump: Fantastic! :jump: 

Here's the graph (sub only) with the four new filters! I think that looks much better--what do you think? 









Now, I'm going to run the mains in with the sub--I just plug in the L channel from the soundcard to the AVR and turn on my Speaker A on the AVR, right?

Here's the graph for that:









I still have a nasty dip about 65hz--anything I can do for that?

Thanks so much for the great help!!! :T 

-- Phil


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## brucek (Apr 11, 2006)

> I still have a nasty dip about 65hz--anything I can do for that?


1) Adjust the phase dial switch of your subwoofer amplifier.

2) Adjust the subwoofer distance setting of your receiver a small amount (couple feet back and forth)

3) Move the subwoofer.

brucek


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## allredp (Feb 7, 2007)

OK, here's the phase adjusted to 180 degrees (originally at 0):









Here's the original 0 degree phase graph:









So, this is much better overall. It shifted the dip to 72Hz, and softened it some--looks like some of the other FQ were also positively affected!!! :bigsmile: 

Wonderful! That's moving in the right direction. 

Sadly my AVR doesn't have a sub distance setting! Nada, zip, zilch... :rant: 

Question: Just for complete clarity, I don't have to do anything other than plugging in the L channel and turning on my mains to test this, right? 

I'll experiment with some other phase settings, and possibly try a little sub movement--I'm limited in what I can do that direction...

BTW, Ken (I'm sorry I've been calling your Bruce :nono: ) would you advise a small boost of that 72Hz? If so, how much would you guess at what bandwidth, etc.?

-- Phil


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## Otto (May 18, 2006)

allredp said:


> So, this is much better overall. It shifted the dip to 72Hz, and softened it some--looks like some of the other FQ were also positively affected!!! :bigsmile:


Yeah, looks much better! :T 



> Sadly my AVR doesn't have a sub distance setting! Nada, zip, zilch... :rant:


Does it have a time delay setting for the mains and/or the sub? That would work equivalently, where 1 foot ~1 mS. The shorter the time, the "closer" the speaker.



> Question: Just for complete clarity, I don't have to do anything other than plugging in the L channel and turning on my mains to test this, right?


That sounds correct. Additionally, I'd just leave L and R connected from the PC to the AVR all the time. Then, mains on, re-run the sweeps.



> BTW, Ken (I'm sorry I've been calling your Bruce :nono: ) would you advise a small boost of that 72Hz? If so, how much would you guess at what bandwidth, etc.?


I would try it if I were you (or Ken, but I know brucek won't recommend it :bigsmile: ). Looks like it's almost 10 dB down from where you are at 60 Hz. Just watch your levels. Does it sound better? Another alternative is to turn up everything and continue to quash peaks. Also, are there any filters already nearby that you can tweak with?


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## brucek (Apr 11, 2006)

> OK, here's the phase adjusted to 180 degrees (originally at 0):


You're done...... many don't get it that good. 



> I'm sorry I've been calling your Bruce


With two first names, you can bet about half the people call me bruce... that's why I use brucek. 

Hopefully, after all your work it sounds better?

brucek


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## allredp (Feb 7, 2007)

Thanks for the ideas, Otto. I appreciate the help. 

I must say that things are sounding really good right now.

Ken, you are da MAN! :flex: I really appreciate your step-by-step help with this. I have some mental block about new things--especially technical gadgets. But, with your patience I've been able to get this done right and make my investment in my SVS and the BFD really worth it! 

The Shack and all those involved in making (JohnM) and elucidating (Ken, Wayne, Sonnieet al) REW and the BFD are to be seriously thanked!!!

Yes, Ken, what a difference the BFD filters are making! :woohoo: I can really tell the difference. 

I tried WOW chp. 5 where the machine emerges. :holycow: I've played that a fair amount and was thrilled that the one-note sound was gone. I have very distinct sounds now that are free from bloating. I'm hearing different noises now--not just the same note louder or softer.

Next I worked over some favorite music--John Mayer's _Continuum_ is also free of heaviness and rewardingly distinct. I also have a great song redone by B-Tribe that has very heavy deep bass which usually drives my wife from the room :rolleyesno:. Now it is just powerful without boominess. Other selections (Sting, Jesse Cook, Simple Minds, Enya) are sounding better than ever before!

The killer and most satisfying scene is the famous "ring drop" in FOTR EE DTS ES. I've always heard people talk about this as so impressive. However, my room must have been killing that fq, because neither my SVS, nor my M&K could produce anything worth noting there! It was loud, but nothing special. It was so frustrating--especially buying this fairly expensive SVS (PB12+/2), not to experience what so many others have exclaimed about. Well, thanks to REW and the BFD I get it! Now I love it. When the ring falls it hits with authority and clarity! :fireworks3: The following reverse sweep is really powerful and no drops to speak of. My 15 yr. old son who had worked on calibration and placement with me was notably impressed with the difference. He high-fived me and said "congratulations" (he's watched me be tortured over setting up REW, etc.)

Interestingly, my favorite scene with the previous one-note unfiltered setup was the Council of Elrond scene in FOTR EE (chp. 27). Previously that had just rocked with waves of pressure throughout the scene--albeit with one main effect. Now, it is ever-so-slightly less pressurized, but has multiple varied LFE effects. I don't mind the difference--apparently that's what the scene was designed to sound like. 

So, Ken, my great appreciation to you again! :thankyou: 

I'll take your advice and just let further tweaking go (for a little while at least  ). Besides, my wife is calling for a :time-out: on all this calibration stuff :bigsmile: 

-- Phil


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## allredp (Feb 7, 2007)

Oops... After such spectacular results I should have left well enough alone... but, I decided that I might experiment with a more aggresive filter set to catch that dip at 70hz and try a house curve.

Problem is once I unhooked all the gear so I could watch my HTPC through its SPDIF digital out and have now rehooked up all the REW input/outputs, etc. I have something goofy going on.

I've run through the usual soundcard preparations (meaning I've set the speakers to stereo, disabled the SPDIF output, made sure the RS meter is connected to the blue, and my green output is being stereo to mono split out to my AVR. I've even unhooked the SPDIF output and unplugged/replugged my analog output plugs (green)--even repeatedly rebooting the HTPC to make sure my soundcard is auto-detecting appropriately.

What's happening is that I'm getting some pronounced fuzz from my front R speaker and when I turn up my volume much to get my SPL at 75db I begin to get feedback from the RS meter! I'm also getting that loop effect in my graphs like before--sounds like I need to turn off something in my record mixer, right? Well, I've been trying that with no results. I have the line in selected and nothing else. I have gone to my AC97 UI and turned off the digital output and selected stereo and no soundeffects. 

Still, everytime I reboot I end up having to reselect the AC97 soundcard--and when I go to start REW it has a screen that says I have no input mixing drivers (something about PCM stereo). Here's the screenshot:









Help!

One more question also--how do I turn off, delete filters? I know how to set them, but what do I do if I want to ditch old ones (e.g. I had originally 4, but then overwrote those with a new 9 a couple days ago)--how do I go back to those original 4. I know how to overwrite the first 4, but what about the last 5? Is there a way to turn them off? 

Thanks as always.

Phil


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## Otto (May 18, 2006)

Hi Phil,

Not sure about the soundcard thing. Is there a setting in your control panel that tells it to turn on SPDIF that then implies that analog is OFF?

As to killing filters, just to the left of each filter setting in REW is a pulldown that allows you to select "PA" or "None". Select "None" for the ones you don't want, and it should wipe them out. You can also do it through the BFD itself, but I can't quite recall how. I think it's the "Filter" button on the front panel, and then you can jog dial to each number, and select "OF", "PA" of "FB" I think (off, parametric and feeback destroyer modes, respectively). Something like that....


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## brucek (Apr 11, 2006)

> how do I turn off, delete filters?


Set the Gain of the filter to zero or turn its mode to 'OF'



> when I go to start REW it has a screen that says I have no input mixing drivers


Once you have the soundcard working in Windows with the analog working, then start REW and go to the Settings pulldown and select Delete Settings and Shutdown and then restart REW and redo your settings. 

Switching between an HTPC and REW duties is always going to take extra messing around. You should get some resonable filters set (which you already have accomplished) and maybe call it a day. Or, best find an old laptop to use with REW....... 

brucek


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## allredp (Feb 7, 2007)

Thanks Otto--I'm not an owner of a midi-setup, but that could change one day!

Ken, sage advice. I'm hanging onto the original 4 filters (25, 40, 50, 80hz) and calling it a day. I was able to set the gain to 0 on the other filters in #4 and they appropriately disappeared from the BFD LEDs. Cool, I know how to do that now. 

When I decide to undergo another technological game of twister, I'll work that last bit of counsel in and I'm sure that will make things work...

For now the sound is noticeably better--mission accomplished! :yes: 

Thanks again,
Phil


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