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Discussion Starter · #1 ·
I did some measuring the other day with my new PB-2000 and the mains on at the same time. I may be posting prematurly since I still have a lot of data to gather, but I wanted to see what everyone thinks initially.
140325 sub with mains.jpg

140325 sub with mains spectrogram.jpg

View attachment 140328 room Assembly2.zip

The zip is there for fun. It is a 3D model of my room I have been working on during lunch. It is an Autodesk Inventor viewer file that opens in internet explorer.

I think the spectrogram shows the most. Can someone tell me if I am interpreting correctly? I think that I have a big room gain below 60 hz that causes the 2 big humps. I think that means that I need to do something about bass traps/room treatments. For now I am thinking of using equalizerAOP to reduce the humps then turn up the sub so that it removes the low spot around 70-80hz. I have plenty of room on the sub volume. I also think I need to do the 2 mains individually from MLP and the sub individually from MPL, then do FR and sub, FL and sub, then some overlays to see if I have a phase issue around 200hz.

What does everyone think?

Thanks
 

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Are you using the crossover in your AVR, and what is it set at? What do you have for mains? Sorry, not familiar with your system :). Looks like you might be crossed a little low, for starters.
 

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Discussion Starter · #3 ·
I am crossing over at 80Hz using my Yamaha AV receiver. The sub is connected to the LFE and the crossover knob is all the way up at the LFE setting. My speakers are an old pair of Kossfire floor standers. They have roughly 10" woofers.

679373-koss_kossfire_speakers_model_210.jpg

This is a set of readings I took a while ago with the old sub turned off. I was a little low on the volume I think, but the idea is there.

140315 mains.jpg
 

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I am crossing over at 80Hz using my Yamaha AV receiver. The sub is connected to the LFE and the crossover knob is all the way up at the LFE setting. My speakers are an old pair of Kossfire floor standers. They have roughly 10" woofers. This is a set of readings I took a while ago with the old sub turned off. I was a little low on the volume I think, but the idea is there.
Have you tried different sub placement, and phase adjustments?i agree with taking all the other measurements, and doing overlays and such. I was able to cure a big null with only a phase adjustment. Btw, those are some really cool looking speakers.
 

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Discussion Starter · #5 ·
Thanks for the compliment, those speakers were my father-in-law's before he passed. I like those big ole speaks.

I played with the phase quite a bit to get rid of a null at 57hz. Weird thing is it seamed to cause the null at 200. There is something I don't fully understand, but I feel like I am close to understanding.

Could the phase change I made in the sub made a reflection bounce into the 200 hz. That doesn't sound right, but I don't know how to explain changing phase in the sub causing a change at 200hz. I can take any measurements that will help explain.

I am trying not to move it far. The WAF is golden right now, so if i can keep it in the neighboorhood of where it currently is, no problems. The room sim shows it is a good location, so i figur it should work close to there if I play with enough settings.....maybe.
 

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Thanks for the compliment, those speakers were my father-in-law's before he passed. I like those big ole speaks. I played with the phase quite a bit to get rid of a null at 57hz. Weird thing is it seamed to cause the null at 200. There is something I don't fully understand, but I feel like I am close to understanding. Could the phase change I made in the sub made a reflection bounce into the 200 hz. That doesn't sound right, but I don't know how to explain changing phase in the sub causing a change at 200hz. I can take any measurements that will help explain. I am trying not to move it far. The WAF is golden right now, so if i can keep it in the neighboorhood of where it currently is, no problems. The room sim shows it is a good location, so i figur it should work close to there if I play with enough settings.....maybe.
Yeah, fixing the null at 57, could have caused the one around 200. I'm using your first graph, and it looks like the dip at 200 seems narrow-ish, so it might not be too noticeable during playback. I wonder if moving your mains a little bit would help that. A 200hz wavelength is just a little over 5-1/2 ft long so it would be sensitive to small movements. Just afraid it would make a mess somewhere else. What are your room dimensions, and where are your mains compared to the walls? I definitely understand the WAF. I've been pushing mine to the edge for a long time! If the sim looks good, and WAF Is good, I'd agree with your theory about settings, and eq and such. ...
 

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Discussion Starter · #7 ·
The room is 17 x 24. We sit facing the long wall. The speakers and sub are about 2ft off the front wall. We sit about 4-5ft from the back wall. The mains are symmetrical at 7ft in from the short wall. The sub is dead center. Puts us 10 ft from the sub and the projector screen. My screen is 4 x7 ft in between the mains. I sit offset left almost mid between the sub and left main. The zip file is cool shows it all in 3D. The mains are sitting on a shelf about 28" off the floor.

I had not thought about the wavelength at 200hz. If it's 5.5 ft, we are at about double that.
 

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The room is 17 x 24. We sit facing the long wall. The speakers and sub are about 2ft off the front wall. We sit about 4-5ft from the back wall. The mains are symmetrical at 7ft in from the short wall. The sub is dead center. Puts us 10 ft from the sub and the projector screen. My screen is 4 x7 ft in between the mains. I sit offset left almost mid between the sub and left main. The zip file is cool shows it all in 3D. The mains are sitting on a shelf about 28" off the floor. I had not thought about the wavelength at 200hz. If it's 5.5 ft, we are at about double that.
Yep, you are at about double that. Multiples of even displacements are often problematic. I noticed your fronts are close to 1/3s. That's good. 1/5s is usually also. I'm still waking up, but it occurred to me, that at 17', you have a room mode at 199.41hz! Ironic? I think not. I think I might try moving the mains closer/farther to the front wall to bolster that range around 60 and up. If you then pull the peaks down in the subwoofer range, it should flatten you out...maybe. ...I'm gettin some coffee. Then I'll get out the pen and paper! Btw, my phone won't open the zip. I'll hit my PC later. Sounds cool.
 

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Discussion Starter · #9 ·
Would moving seating toward the speakers have the same effect as moving the speakers away from the walls? Maybe a compromise.
 

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Yes, that could work. You might wanna wait a little til she breaks in too. I think she'll open up a lot, and that will change your graphs. Btw, new A7X(hail to the king), has a nice full, rounded low end. New Korn is solid too. ...saw your nod to megadeth.
 

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Discussion Starter · #11 ·
Thanks for the help. I haven't listened to any korn in a while. Great suggestion. I'll check them both out.

I spent all day yesterday raising my shelf/screen 7". My lense shift was maxed an gave me a bit of distortion. Gonna take a break today. I'll eq the humps down and restart calibration in a month or 2.
 
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