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Discussion Starter · #1 ·
Good afternoon all!

I have reached the point where I am trying to determine if the bass trapping I have done to this point is not enough / sufficient / too much and then continue on to full room response.

I have been moving subs and mains around to determine best possible locations and I hit a point with a question.

Here is the response I had with the 2 subs:

12-9 subs.jpg

With that steep of a drop in SPL after around 50 Hz, am I looking at an example of too much trapping? I am not certain if the amount of trapping I have done has deadened the room or if I have something else going on. I have front corner super traps and the soffits were built to absorb from 20-200 Hz. The crossover is set in the AVR for 80 on both the mains and CC and the LPF of LFE is set to 120 Hz.

I attached the mdat file for the sub measurement. Any suggestions / constructive criticism welcome! :bigsmile:

Thanks!

Joe
 

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Couple of questions Joe.
  • What mic are you using?
  • Did you calibrate the sound card?
  • What sub are you using? Is it ported?
 

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Discussion Starter · #5 ·
Couple of questions Joe.
  • What mic are you using?
  • Did you calibrate the sound card?
  • What sub are you using? Is it ported?
Dale,

I am using the CM-140 for a mic and I did do the sound card calibration. I have 2 of the SVSOUND PB-13 Ultras and both are ported. I have not plugged any of the ports and have the setting on 20 Hz.

How big is your room? Is that sub-only with or without LPF?
The room is roughly 14' wide by 19' long with a height of just under 7.5'. If you mean the LPF setting on the AVR, I have that set to 120. On the subs, I have the crossover turned off.

Thank you both for your help. If it helps, I can post that graph with the sound card cal on......
 

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Your room isn't that big and with a low ceiling it isn't a huge volume, I'm wondering if your room contribution is dominating your response. Unless the subs are out into the room and not in the corners, the room interaction shouldn't be making anything dip. Can you block the ports on your PB13s (if they are meant to do that) and repeat measurements? Your room might do best with sealed subs...
 

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Discussion Starter · #10 ·
Got some time today to do more measurements!

First thing I did was to plug ports and retest (after changing the setting on the back) sealing it, then removing one plug at a time. I saw a drop in SPL, but the overall pattern of the response was the same.

So, I started really moving them around and taking measurements. Let me say - REW is a wonderful thing!

I made it to this point - I got one in the middle of the front wall and one toward the front corner where my sump pump closet dips out (I will try to get a photo up later to give a visual). Here is what I ended up with for a response:

12-10 two subs mids.jpg

I am by no means an expert, but that does not look half bad. This is only with the two subs - I have not done the mains as of yet (well, I did them by themselves but not with the subs) but this looks like something I could work with on the ydp2206 EQ.

What do you guys think?

View attachment 12-10 two subs mids.mdat
 

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That looks much better! I'm surprised that plugging the ports didn't make a bigger difference. Since it didn't, you might leave them plugged since you apparently don't need the extra LF. You can verify from the waterfall, the persistence below 30Hz could all be the room... I'd set your LPF at 80-90Hz and give the system a listen and see how you like it?
 

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Discussion Starter · #12 ·
Spent a few more hours doing measurements - I moved the mains around and incorporated them as well as the CC - both are crossed over at 80 Hz. Here is the response I came up with:

12-10 lcr and subs.jpg

As I have no point of context, I am not sure if this is bad or good. I think it looks pretty good (before EQing) but would love to hear other people's opinions.

I am including the waterfall - except for 60 Hz and below @25 Hz, it looks like I have sufficient trapping if I am reading it correctly. Does that look correct?

12-10 lcr subs waterfall.jpg

As always, I am attaching the .mdat files and thanks for any assistance!

Joe
 

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Discussion Starter · #13 ·
That looks much better! I'm surprised that plugging the ports didn't make a bigger difference. Since it didn't, you might leave them plugged since you apparently don't need the extra LF. You can verify from the waterfall, the persistence below 30Hz could all be the room... I'd set your LPF at 80-90Hz and give the system a listen and see how you like it?
Ha! You snuck a post in on me! :)

I forgot - in the measurements I just posted up - I did find that plugging one of the ports on the front sub gave me a bit more even response @20 Hz so I left it plugged for that measurement.

I never considered if plugging the ports would tame some of that persistance below 30 Hz - I will plugs the ports tomorrow and see what happens. I am actually going to be adding a 3rd sub in the room and locating it in the rear corner of the room - I was able to talk my wife into getting me a PSA XS30 for Christmas. :devil: With that being the case, I will probably plug them when I incorporate it.

Now, I just need to read through the documentation on the ydp2206 EQ and see if I cannot try to do a house curve. I got 2 of them used so it is worth a shot.....
 

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Discussion Starter · #14 ·
Finally got a chance to do some measurements experimenting with plugging ports. I found that plugging all ports on both subs really tamed that persistance below 30 Hz - good call mate! :)

So, prior to adding the 3rd sub, here is the response I think I will be going into EQ with:

12-13 lcr subs sealed.jpg

Here is the associated waterfall:

12-13 lcr subs sealed waterfall.jpg

Will be trying my hand at full range measurements next......

View attachment 12-13 l-c-r subs sealed.mdat
 

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Discussion Starter · #16 ·
The sub in the front of the room is pretty much exactly in the middle of the wall. The one on the side wall is closer to the end where the sump pump is.

I noticed when I was moving the side wall one around that the further I moved it from that corner, the more dips I saw.

Really anxious to get the XS30 in here and move them around a bit again to see how much better I can get it. Plus, I have only measured from the main LP to this point. When I get time, I will take measurements from the other listening spots and see what kind of response I have there. As I will always be sitting in the main LP, that was the one that was important! :bigsmile:
 

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Discussion Starter · #18 ·
Exactly what I thought - I started off in the middle of that side wall because I thought that would be the best location as you suggested. But, it just kept getting better as it moved closer to the corner!

I have ordered the Master Handbook of Acoustics - it just bugs me to look at results and not know if it is a good response or not! Hopefully, I can at least get to a point where I will not need to post every graph and ask how it looks.... :R
 

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Discussion Starter · #19 ·
Now that I received the XS30 and I am nearing the end of the construction road, I will be getting back on the REW wagon! I started taking measurements and finding the best locations for the mains. Placement is very limited so I am going to have to accept some shortcomings, but I hope to smooth everything over with the 3 subs.

More to come.....
 

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Discussion Starter · #20 ·
So, after a few hours of moving subs and mains around, I got to this point:

1-31 all 5.3 channels.jpg

I was really happy with the way it came out - it looked like a great starting point for a house curve.

Then, I ran Audyssey thinking it would dial it in further. Here is the post Audyssey REW result:

1-31 5.3 channels with aud run.jpg

I was astounded - I made an assumption (and probably a bad one) that Audyssey would only make it better. So, I turned Audyssey off and thought "no problem, I will just turn it off and be good to go". No such luck:

1-31 aud now turned off.jpg

Of course, I foolishly did not write down pre-Audyssey settings so I could not get back to where I was. So, I am in the process of trying to get close to where I was before.... more to come!
 
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