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How to start measurements when you have multiple subs

16K views 97 replies 6 participants last post by  thsmith 
#1 ·
REW is working for me now and no more manual measurements, yahooooo!

My room (Living room)as most everyone elses is challenging, 4200cf, 8' to 12' sloping ceiling, hardwood floors, fireplace is 10' wide and 12' high. 6' frech door, all windows have heavy drapes and large opening in back of the room to the right from sitting position.

I have a HSU VTF3-MK3 Turbo in front left corner and HSU MBM-12s behind each main.

When I start my measuring I know I need to remove the mains, should I also turn off the MBMs and focus on just the 3 3 T and then turn off 3 3 T and turn on 1 MBM at a time to find best location for subs ?

3 3 T XO is in set at 55hz
MBMs XO out (50hz-150hz)
AVR (Denon 2808) XO set to 120hz

Thanks
 
#34 ·
Take some comparison graphs of the 3.3 in 0 versus 180 phase like brucek mentioned. Also try max extension versus max output mode. I take it, this last graph was with the mains turned on? Keep the turbo off for now. We will add that variable later.
 
#35 ·
Thanks Bruce. I have added a pic of my room in case that helps.

I will move the sub tomorrow to see if I can tackle the 32hz dip. Unfortunately the sub only has 0 and 180 degree phase adjustments but I will try it as I move the sub.

I also want to put one of the MBMs near field and see if it will integrate. Looks like the only place it might help is the 70hz dip.

Are there other graphs I need to look at that may reveal a need for BFD?
 

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#37 ·
Unfortunately the sub only has 0 and 180 degree phase adjustments but I will try it as I move the sub.
You may also use the subwoofer distance setting in the receiver. It is a close proxy for the phase adjustment.

Are there other graphs I need to look at that may reveal a need for BFD?
Waterfall plots will reveal the time domain. Use the same scaling as response graphs.

brucek
 
#38 ·
Here are my latest measurements with just the 3 3, no turbo or MBMs. I used different phases combined with AVR distance. Audessy has the sub at 20' but real distance is 14'. I made test on distance focused primarly on these 2 ranges as either side of 14' and 20' had worst results.

Looks like second graph is the best.

1st graph is phase 0 AVR distance 14'
2nd graph phase 0 AVR distance is 20'
3rd graph is phase 180 distance 14'
4th graph is phase 180 distance 20'
 

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#40 ·
I would agree on the second also. How does it sound? Are you planning on a BFD? Have you read about making a house curve? Depending on your answers to these questions will help decide what your next steps are.
 
#41 ·
Sounds ok not as strong as it was before with MBMs. Also I think I screwed up as I had Audessy on during my testing so I need to redo with out it.

Have not gotten to the House curve reading yet, sounds like once I can get back to chart 2 without audessy then that would be next steps.
 
#42 ·
That's what I found too. When the bass is flat with the highs, everything sound FLAT. No depth to the music. You are going to want to start reading the house curve sections next. It sounds complicated, but it is not too bad. It will be the most subjective part. Meaning your ears will be the deciding factor.
 
#43 ·
Well Audessy is definately helping me in the 33hz dip. Without Audessy I am unable to raise that dip by moving the sub in its corner which I have about 24"s to play with. I am able to raise the 72hz by setting phase to 180 and using the distance as measured from sitting position.

How important is it to take Audessy out of the equation ?
 

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#44 ·
How important is it to take Audessy out of the equation ?
You can keep it on for now. Even with it, it is clear you could benefit from a BFD. If you choose to pursue a house curve, you will probably be fitting Audessy and will definitely need a BFD.
 
#45 ·
Weverb, I do not understand. Where and how would I benefit using a BFD, lower my peaks ? It looks like I have a lot to deal with. Should I start setting filters to see how flat I could get without actually having a BFD in order see at least graphically what could be done.

Briefly reading the house curve article it looks like you first need an EQ, is the correct?

Kind of lost in the digital dust or analog dust at this point.

I do know that I have really done nothing except shut down the MBMs, taken off the Turbo and changed the phase on the sub and distance on the receiver.
 
#46 ·
Weverb, I do not understand. Where and how would I benefit using a BFD, lower my peaks ? It looks like I have a lot to deal with. Should I start setting filters to see how flat I could get without actually having a BFD in order see at least graphically what could be done.

Briefly reading the house curve article it looks like you first need an EQ, is the correct?
Yes, a BFD will help tame those peaks and get a smoother response. I would start reading Wayne's very informative section about filters. Make sure you understand the basics and then you can start playing with filters.

A BFD is very important to dialing in a house curve. You can start doing the listening and measuring point now. You will probably have to revisit it after you smooth out your current situation.
 
#48 ·
Sub graph with filters - Feedback/direction Welcomed

Not sure I have this right but here goes. SUB only on (HSU 3 3), AVR xo at 80hz and Audessy is on. Without Audessy I have a nasty dip at 35hz. Do not have a BFD yet but simulated using 1124P

REW picked 6 filters. I set max peaks to find at 70hz as I read you do not want to use filters at the XO.

Thanks in advance for feedback and directions.
 

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#50 ·
Thanks David, AVR (Denon 2808 does not a sub EQ just the other speakers and goes down to 63HZ. Not sure why having Audessy on helps me at 33hz (just sub or sub and mains). The chart looks better but it the sound has alot less punch.

I have a new post with just sub and sub and mains letting REW pick the filters.
 
#51 ·
#52 ·
Re: Sub graph with filters - Feedback/direction Welcomed

Just to let you know, you probably could get away with only 2 filters (the first two). :bigsmile:
 
#55 ·
You can now start reading about house curves. Let's get those MBM's back! :bigsmile:
 
#56 ·
Yep that is in the plans. I did pick up a 1124P yesterday but did not have time to pick up the right connectors and cables, will do that today.

I think first I will focus on just the 3 3 going through the entire process using filters then load a house curve and once I get to a happy place then start to integrate the MBM or MBMs.

Seems integrating the 1124P should not be too tough, famous last words.

Was kind of surprised that once I have the input level on the BFD setup that to balance the sub and mains I will have to use the sub amp which will make balancing the sub and MBMs more challenging.

Hopefully next post will have some correct measurements and graphs leading up to the house curve which should be the next steps.
 
#57 ·
BFD 1124P is now integrated with system.

First graph is measurement with using auto filter instructions. Rew identified 2 filters.
Second graph is measurement with both filters applied to BFD no smoothing.
3rd graph is measurement with both filters applied to BFD 1/3 smoothing.

Looks good to me and I can see where the filters have reduced the peaks as intended.

Looks like next steps are to set up a house curve. WHen setting up the house curve will it get set as a 3rd filter ?

Thanks,
 

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#58 ·
Do not use smoothing for sub graphs. Looks great otherwise. You may be able to do something about that dip after 70Hz. Don't know where your xo is set though or how thing look with your mains on. No, a house curve is not a 3rd filter. You will probably create a few new filters once you develop a house curve. They can be saved to a different memory setting in the BFD. I have two saved on mine. One has Wayne's hard knee house curve settings and the other has one with a little more mid-bass, but still a 6dB house curve.
 
#59 ·
kewl weverb. Graphs were with just the sub and the xo is 80hz.

Just trying to feel more confident about REW and what I am doing so keeping it simple.

Thanks for the feedback and confirmation. I will start working on the 70hz and see how it looks with mains on.
 
#61 ·
Looks good.
 
#62 ·
I have setup a house curve just as a test sample as seen in the graph below.

Where I am lost is what to do next, I have read Waynes House curve article several times but just don't get the next step.

I have my 2 filters loaded to make my bass flat.

Suggestions very much appriciated.
 

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#63 · (Edited)
Turn up the dial on the back of the 3.3 to get the 15-30Hz section to straddle the target line like your graph does in post #60. Then create new filters to bring down the rest of the response to the new target line. Save these settings to a different memory position. Redo the steps for measuring for a house curve to verify they "sound" the same volume. Play some of your familiar reference material (music, movies, etc.) and see how it sounds.
 
#64 ·
AH-HA ! 2 more questions for clarification.

Turn up the dial on the back of the 3.3 to get the 15-30Hz section to straddle the target line like your graph does in post #60. Am I still using the previously created filters in the BFD ?
Then create new filters to bring down the rest of the response to the new target line.
Will the previous 2 filters need to added in manually or they irrelevant at this point?

Was the whole point of getting the bass response flat using the 2 filters to just see if it is possible then at the point you set the House curve and create a whole new set of filters?
 
#65 ·
The point of getting it flat was to make everything measure the same so that it would be easier to calculate how much of a dB slope you would need to make them "sound" the same.

I would save/copy the setting you have in post #60 to another memory setting (say #9). I would temporarily bypass the BFD and then turn up the 3.3 until the 15-30Hz section straddles the target line. Once that is dialed in, repeat the steps you did to create the original 2 filters. You may only have to turn down the gain on the two you already have, or you may need to create three new ones.
 
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