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Klipsch SUB-12 Subwoofer (1 Viewer)

BraveHeart123

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Ok but my probelm is that YPAO on RX-V3900 sets my mains to large during calibration and sends them full signal then it applies PEQ setting to them for acoustical correction, which I think is wrong becasue I dont want my mains to run as large and the PEQ settings are as per large. Changing them back to small is easy but PEQ is still set for the large. Shall I not worry about it?
 

Robert_J

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Don't worry about it. For the frequencies that are still sent to the speakers, the PEQ settings still apply. If (and it's a big if) they EQed anything under 80hz on your speakers, it won't matter anyway.
Subs are a different story. It may be a small range of frequencies but they are the most impacted by the room. From 100hz to 15hz, you can have multiple peaks and valleys. If the peaks are large, you want to tame them and run YPAO again. If it is anything like MCACC, it sets the level based on the largest peak. In my case it was a 14db hump at 55hz caused by the inductance of my subwoofer's voice coils. I used a BFD to pull that peak and 2 others down as well as boost the low end a little. I used 7 of the 10 filters available to me on that EQ setting. The nice thing about that EQ, I can dial in any subwoofer frequency response I want and save it in one of the 4 (maybe 5) memory banks.
 

BraveHeart123

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Ok got it. I downloaded sine wave generator (NCH Tone Generator) n its fairly easy to use.
Do I need to create pink noise sine wave files??
Also can u pls specify how many test tones do I need to generate from 20 hz to 120 hz??? Wat I mean to say is.....should each test tone be 1 hz apart like 21, 22, 23, etc?
Also, do I need to save every test tone as a seperate wave file e.g. 40hz.wav, 42hz.wav, 100hz.wav??
 

Robert_J

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Pink noise is across a range of frequencies. Sine wave is a specific frequency. You want sine waves at the same frequencies as the PEQ spreadsheet (post 14). Each one is saved as a separate file. Yes, it's a pain but you only have to do it once. I'd do 10 seconds each. On your burning program you can put a 20 second gap between tracks.
I guess I used NCH as well. I have a bunch of their software installed.
 

BraveHeart123

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I was just looking at the spreadsheet in post 14, it has multiple tabs i.e. BFD, Measured Response, IO Data, EQ Data, and Settings. I guess this is for BFD, which I don't have. How do I use it??? It uses 1/60 octave setting, whereas my AVR can dig to only 1/3rd octave.
I've noted these frequencies (20 / 25 / 32 / 40 / 50 / 63 / 80 / 100) from Frequency (Hz) cell in the BFD tab. Are these the ones for which I need to generate sine waves???
 

Robert_J

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You need to create .wav files matching the frequencies on column A of the Measured Response worksheet. As you measure, you enter your SPL into column B. Choose the RS Calibration from the drop-down. Column E becomes your actual SPL at each frequency. Then go look at the BFD worksheet and uncheck all filters. That is a graph of your sub's in-room frequency response. Then you can simulate a BFD in software. If you can flatten the response in software, you can do the same in real life if you buy a BFD.
 

BraveHeart123

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Robert_J said:
You need to create .wav files matching the frequencies on column A of the Measured Response worksheet. As you measure, you enter your SPL into column B. Choose the RS Calibration from the drop-down. Column E becomes your actual SPL at each frequency. Then go look at the BFD worksheet and uncheck all filters. That is a graph of your sub's in-room frequency response. Then you can simulate a BFD in software. If you can flatten the response in software, you can do the same in real life if you buy a BFD.
1. So does it mean that column E becomes my actual SPL reading and not column B? What do the other columns in Measured Response tab mean?? Is there any usage manual available on this spreadsheet???
2. There is a drop-down list at the bottom of BFD tab containing 2 values (Measured Response and Imported FRD)??? Which one do I select???
3. My AVR uses 1/3rd Octave PEQ settings, whereas x/60 octave is used in the spreadsheet....um lost. How to go about it???
3. What do u mean by "Simulate a BFD in software" ???
It will be a great help if u can explain the exact stuff that I have to do in this spreadsheet instead of me bugging u again n again over things that may be tiny for you but they confuse me big time. thanx
 

Robert_J

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1. Yes. The Radio Shack meter is not accurate across the entire frequency range so correction values for each frequency are applied.
Column C are the RS correction values. Column D are the custom values you would use if you had a different meter. I don't know about the other two columns.
No manual but you may be able to send Gomer a PM here. He is a member. In fact my sister met him when I bought some of his subwoofers years ago. He wouldn't ship but they were local to each other. Nice guy.
2. Measured response.
3. The BFD tab literally simulates a Behringer Feedback Destroyer in the software. As you apply filters on that worksheet, you can see the response graph change. Get it like you want it and then enter those settings into a BFD. When I measured a 2nd time, the response graph was exactly as the software had predicted. If you aren't sure what a BFD is - http://www.amazon.com/Behringer-DSP1124P-Suppressor-Parametric-Equalizer/dp/B0002E58D8 and http://www.behringer.com/EN/Products/DSP1124P.aspx . There is a "pro" model out that is more expensive but completely overkill for sub EQ duties.
I don't mind. I'm used to training people in remote locations so this is nothing new. Only the subject is much more fun.
 

BraveHeart123

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I was finally able to measure the response of my room today. Here's what I did;
1. Ran YPAO along with auto PEQ/distance/level etc.
2. Then calibrated all 5 speakers to 75 db and subwoofer to 80 db at my reference volume on AVR using Avia I and RS analog meter.
3. Set the volume at the reference level on AVR and played all the test tones (Created using NCH) one by one and noted the SPL in "PEQ ver 1.05b1" after setting "RS Calibration" in Measure Response tab. I only created test tones from 20Hz onward coz my sub goes as low as 24hz.
I am attaching the Measured Response along with the frequency/SPL sheet. Pls advise me on what to do next
[ATTACHMENT=139]RoomResponse.JPG (127k. JPG file)[/ATTACHMENT]
[ATTACHMENT=141]FrequencyData.JPG (67k. JPG file)[/ATTACHMENT]
 

Robert_J

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Pls advise me on what to do next
Looking at the graph, you want to pull the peaks down to the green line (or between the line above it and the line below it which will be + or - 3db). The first peak is a pretty wide one starting at 35.5 hz and ending at 44.7hz (see the 2nd attachment for exact frequencies). On the PEQ tab, set the first frequency to about 37hz. Put the gain at 0. Click the On check box. Now adjust that filter down (lower the gain). You want to adjust the bandwidth to make the filter wider or narrower as required. Do the same for the 2nd filter but put it near 41hz. These two filters will pull down the first peak. You probably only need 1 filter each for the 2nd and 3rd peak.
That first peak is almost 9db which makes for a very boomy sound. I suggest getting a BFD and adding it to your system. You can see the predicted frequency response on the spreadsheet and it is very accurate to what you can get in real life. You can get the BFD and a pair of cables for under $100.
 

BraveHeart123

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Sorry.....All channels were set at 85 db and sub at 88db.
I had mentioned earlier that I didn't have BFD and it's not avaiable here in Pakistan.
All I can do right now is to play around with the built in PEQ (1/3 Octave) in my AVR (Yamaha RX-V3900). It has 7 frequency bands with each band having multiple frequencies in it.
Pls guide me on it.
 

Robert_J

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The PEQ worksheet is technically a generic setup. Only use the first 7 filters. The settings are the same as any parmetric EQ = Center frequency, width and boost/cut.
99% of the members of this forum are US based. There is a nice little feature in your profile to put your location. That allows us to tailor our equipment suggestions to what is available to you. But I'll bet you can find Behringer products somewhere in Pakistan. Google searches on behringer electronics pakistan yield over 140,000 results.
 

BraveHeart123

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Yes Behringer products are in abundance in electronics shops in my town but not BFD. Its mainly recording studio related products. The closest I can get one is from Singapore, which is no problem. I will get it in a couple of weeks.
Anyway, for the time being I am playing with BFD software. I have used the first 6 filters matching the same frequencies given in my AVR to bring the measured response to within +/- 3 db of reference level as much as possible. Since my AVR operates in 1/3 octave, where as BFD software does the same in X/60 octaves, can you pls translate the exact value of Q (bandwidth) in the attached snapshot as per my AVR?
Also AFAIK, smaller the value of Q; wider the bandwith. But the formula given in BFD software yeilds the opposite. It is confusing .... explanation required pls. I am attaching the spreadsheet snapshot.
[ATTACHMENT=147]My_Settings.JPG (96k. JPG file)[/ATTACHMENT]
 

Robert_J

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Odd because the BFD is a live sound piece of equipment. It just happens to have a great parametric EQ that the home theater crowd takes advantage of.
When you set the bandwidth to 60, you are 1 octave wide. Some of your filters are really, really narrow. Try fewer but wider filters. You can also double up on them. One wide and one narrow both on the same center frequency. But you are on your way to getting everything set up correctly.
 

BraveHeart123

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I need to cut the average spike of approximately 10 db between 33.5 hz and 75 hz using PEQ on my AVR.
Pls suggest the value of Q and the middle frequency for a filter, such that it doesn't affect the frequencies below 33.5 hz and above 75 hz.
 

Robert_J

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It's trial and error. That's why you have the spreadsheet simulator. If you are getting too much cut outside of your 33.5 - 75 hz spike, then boost a little on the outside area. The number of filters on the BFD make it extremely versatile. If you using a limited number of filters on the receiver then you can only do your best.
I only had time to glance at this earlier today. Sometimes real life gets in the way of this hobby.
 

BraveHeart123

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Hi Robert....I was in the US a couple of weeks ago and bought this most talked about BFD DSP1124p alongwith two Hosa XLR-to-RCA connectors.
Using the PEQ ver 1.05b1; I've been trying to tame the beast (Klipsch SUB-12) to submission and finally achieved the desired house curve as smooth as possible @least in theory. But in doing so I ended up exhausting all the 12 filters. I will install the BFD tonight to see the theory in practice.
0bd443a1_ResponseCurve.bmp

Looking at the filters, pls lemme know if it is ok to use all the filters. Ive tried every possible location in my room and the current position is the best for this response. I've tried to achieve maximum extension out of this sub at least in my room.
 

Robert_J

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It's fine to use all of your filters. your summed response is a little bass heavy down low for me.
I see you have a 15 db boost down around 29hz. If your average output is 100w without the EQ, that boost will require the amp to produce 1,500w at 29hz. If the amp can't keep up you are looking at distortion and clipping, damaged driver, burnt up amp, etc. Nothing good happens when you boost that much. I EQed my system FLAT and didn't use anything more than a 6db boost. I also have 1,600w of headroom to play with.
 

BraveHeart123

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Sorry but I had to change the sub location. It now sits in the place of bedside table with the port firing towards the bed. I first captured the FR in new location and then achieved the house curve in the simulation spreadsheet.
b3266c7d_BFD_Simulation.bmp

Then i added the same filters in BFD and played my favourite movies. First up, the response was like sucking life out of a novice movie goer with the shock waves litreally shaking the entire bed and brick walls along with very subtle but pronounced LFE details. It was like opening up a new dimension in sound that I never heard in my test movies e.g. Casino Royale, Saving Private Ryan, Prince of Persia, Texas Chainsaw Massacre.
But I wanted to confirm these settings. So, I again captured the frequency response and to my surprise this is wat I got.
I'm a bit confused here. See the response below;
7991c8f0_Response_After_BFD.bmp

That is after reducing 7 db gain on first filter at 22.4 hz and also reducing the sub level on receiver by 5 db. So even after reducing 12 db collectively, the response is nowhere close to what the simulation had plotted in the spreadsheet before adding BFD in the sound chain. Even 60 hz up the response is not sloping smoothly as was predicted by simulation. Am I doing something wrong here or what? Um cross-eyed. Pls advise what to do.
 

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