# Listening mode Question



## gmanned23 (Aug 25, 2009)

I am starting to use REW with some pretty nice results. 

My question is. Which listening mode should i use when using REW. I have used Stereo, All channel, and PLxII Movie. All have given me different results.

I know there is a difference between them but which mode do you guys recommend using.

Thanks

GMAN


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## tonyvdb (Sep 5, 2007)

Hi Joe, it is important to get the main left and right channels EQed properly along with the sub. The surround channels come second and using all channel stereo is the best mode if your looking for an all around flat response on all speakers.


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## glaufman (Nov 25, 2007)

I agree with Tony, but since the main channels and the sub are most important to match, I'd start in 2ch stereo mode (assuming the AVr will be using the sub even in that mode, which some don't)...

and Welcome to the Shack Joe!


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## gmanned23 (Aug 25, 2009)

How does this look?

This is with Stereo mode on. Speakers and Sub.

Joe


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## laser188139 (Sep 19, 2009)

Welcome, Joe. 

That's a start. But it is a little difficult to ensure much because the vertical scale is so wide. That's why the recommendations include the suggestion that the vertical scale be 45dB-105dB. 

Does your graph include smoothing? Generally, smoothing is recommended for full range graphs of the mains, but no smoothing is used for the sub range to see the details. Your sub response looks very smooth, but I'm not sure if this is valid, an effect of the broad vertical range, or from your choosing to smooth the results. 

Did you set the crossover at 80Hz? Perhaps there is a room null there, but frequently a dip right at the crossover indicates that the phase/polarity of the sub needs to be reversed, that the sub is subtracting from the main at the crossover instead of adding to it. 

If you re-post the graph with the vertical scale modified -- no need to take the measurement again -- it would be easier to see if the sub is elevated in level relative to the mains. 

If you do take new measurements, it would also be interesting to see the graph of the sub without the main. 

Bill


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## gmanned23 (Aug 25, 2009)

Here is the graph with the corrections.

I have smoothing set to none under Trace Adjustments.

Crossover for the sub through the receiver is 120Hz.

Joe.


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## tonyvdb (Sep 5, 2007)

What speakers are you using for the mains? 120Hz crossover is a bit high.


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## glaufman (Nov 25, 2007)

Is that a fairly open plan room? Lots of bass traps? Lots of bass EQ? Audessey?


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## gmanned23 (Aug 25, 2009)

I have 2 fairly big fluffy couches. I did run audessy. Also i have 2 bass traps 1 behind the sub and the other on the side towards the wall.

I will try and run a measurement with only the sub and see how it comes out.

As far as bass eq i have none unless you count audessy. I ran it then fine tuned it with my SLP meter.

Also i did the "bass crawl" took me a while but i positioned it in the place where the spl was the best.

Joe


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## glaufman (Nov 25, 2007)

Yes, I do count Audessey. Is the room well sealed or open plan to other rooms?


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## gmanned23 (Aug 25, 2009)

It has 1 opening towards the living room. I will run another measurement with my other PC to see if it comes out the same.

I will post back once i get it done.

Joe


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## gmanned23 (Aug 25, 2009)

Sorry for not posting back quickly.

Here is the subwoofer measurement and speaker measurement (all channels).

These were taken with my PC, i was using my laptop for the other ones.

There seems to be some noise going on at the 72Hz area since its in both charts.

Joe

1st chart - Subwoofer
2nd chart - Speakers (all channel mode)


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## glaufman (Nov 25, 2007)

Do you have 8' ceilings? 7 3/4? 72Hz would be a mode at those distances.
But what changed from your original scans to these? The originals don't show the dip from 90-110?


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## laser188139 (Sep 19, 2009)

Besides smoothing, in the earlier graph the crossover was set to 120Hz. 

Obviously that is no longer the case in the most recent graphs. So the dip around 100Hz is perhaps the interaction of the mains with the room, or perhaps the bottom end of the mains themselves. 

Bill


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## gmanned23 (Aug 25, 2009)

Alrighty i re-measured and this is what i came up with. I used both laptop and PC before so decided to use the laptop for this measurement.

I do have 7 1/2' rear surrounds. They used to be toed down towards the listening position now they are pointing straight forward.

I have adjusted the "phase" in the sub and re-ran audyssey for the new position on the rears. (since i didnt do that on the last graph).

Smoothing is OFF for the measurement, and have fixed the dip at around 100Hz. I did this by just playing with the crossovers, and phase on the sub. Also verified the distances with a tape measure.

Fronts - 80Hz
Side surr - 80Hz
Rear surr - 50Hz -- HTiB rears.
Sub - 80Hz - phase 100.
Listening Mode - All channel

I might have to mess with the position of the rears to see if i can bring that 72Hz down.

Joe


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## laser188139 (Sep 19, 2009)

Besides affecting the dip at 100Hz, did you find that changes to the phase affected the peak at 72Hz, too? I had a similar experience, that changing the polarity on my sub would solve one problem but introduce a worse issue. As you apparently have a true phase control, you may have more options here. 

Did changing the phase affect the distance calculation Audyssey gave for the sub? Or did it leave it alone? 

Given that the other crossovers are at 80Hz, I would certainly raise the crossover on the rear surrounds to match. 

Bill


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## gmanned23 (Aug 25, 2009)

Adjusting the Phase worked great but only for the 100Hz area. I tried and adjust the phase to work for both the 72Hz peak and the 100Hz drop with no luck.

What helped with the 72Hz peak was raising the crossover on the rears to 80Hz even at times to 100Hz but would make the 100Hz drop go even further down. This might be because i have cheap rears i need to upgrade :R

As for the audyssey it didn't effect the distance... maybe its because my receiver has Audyssey 2EQ.

I will raise the crossover on the rears and mess with the phase some more and see if i can lower the 72Hz peak and raise the 100Hz which drops even more if i raise the crossover.

Joe


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## glaufman (Nov 25, 2007)

If the surrounds are exciting that peak at 72Hz, then raising the crossover on the rears would get rid of it, but only if those were the only speakers running... as long as the sub shows the peak, and the sub is part of your scan, you won't see much difference changing the rear crossover.

But to get rid of that you may have to play more with speaker position, listener position, treatments, and/or EQ.


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## tonyvdb (Sep 5, 2007)

Cant changing the subs distance in the receivers settings also help get rid of or at least change some dips and peaks?


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## glaufman (Nov 25, 2007)

Yes, I believe that's true, but usually that's a peak that's caused by a phase problem, what you're doing by adjusting the distance is adjusting the timing and therefore the phase... in this case the peak is there with the sub only, so it can't be a phase issue...

Although it might be an interesting experiment to try and counterract the peak with a phase dip, if that's what you mean... I wouldn't mind seeing the results of that effort....


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## tonyvdb (Sep 5, 2007)

I may actually play around with that myself tomorrow afternoon when I have some time, It made me curious when I thought of that. The distance is a sort of phase adjustment and could also affect how it reacts with reflections in the room.


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## glaufman (Nov 25, 2007)

Looking forward to it!


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## tonyvdb (Sep 5, 2007)

Well, I did some testing yesterday afternoon and adjusting the distance on the sub did very little to change any peaks or dips in the REW tests. I did some really broad swings from 5' to 25' and it did not change things as much as I thought it would. Moving the sub and adjusting the phase really made the biggest changes.
Fortunately my subs are fairly good right where they are I just have a small 10db dip at 60Hz that I cant seem to raise but they sound really good.


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## glaufman (Nov 25, 2007)

I would think you'd want to try smaller increments... too large and you can go right past the good spot... you also could look at it real time with the RTA...


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## tonyvdb (Sep 5, 2007)

Sorry, I should have mentioned that. I did do some small adjustments as well.


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## glaufman (Nov 25, 2007)

Ah well, I can't win'em all


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## cyberbri (Apr 27, 2006)

Here is my sub and speakers, with a different sub distance setting in the receiver. Distances are in increments between 3'6" and 8 feet. You can see how much effect this setting has. 

*Speakers crossed at 70Hz.


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## tonyvdb (Sep 5, 2007)

With the crossover on the sub set at 70Hz your graphs dont make much sense. most of the change is above 90Hz where the sub has little to no impact. Your slight fluctuations in the 40Hz range would not be noticeable as its only about 5db and very narrow. Im not really sure that the distance adjustments made much difference at all.


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## cyberbri (Apr 27, 2006)

The sub still plays a lot above the crossover point because it's a slope and not a brick wall. 

The only change made between the time of taking the different graphs was the sub distance setting. So your comment that "Im not really sure that the distance adjustments made much difference at all" doesn't make much sense at all. Time alignment changes how in our out of phase the other frequencies are.


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## tonyvdb (Sep 5, 2007)

cyberbri said:


> The sub still plays a lot above the crossover point because it's a slope and not a brick wall.


I know that, however by 90Hz it will be almost gone. There should not be that much difference.


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## cyberbri (Apr 27, 2006)

Both of these were taken just now. 

Sub at 70Hz crossover, with mains on, and with mains off.










There's a small boost at 80Hz, and a small cut the same size at 105Hz. 

Here's the sub with no eq, with and without the mains. As you can see, there's a lot of gain I have to deal with.












My receiver is a Sony 5300ES.


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## tonyvdb (Sep 5, 2007)

Thats is correct, what you are seeing is the room interaction with the sub. The stuff on the graph above 100Hz is reflection from the room not what the sub is doing. So in a way yes there is information above the crossover but that is more to do with placement of the sub not distance.
You have allot of reflection, do you have bass traps set up?


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## cyberbri (Apr 27, 2006)

But you can't separate the room interaction from the sub distance unless you completely move the sub and/or seating. That graph literally showed the different sub distance settings at that positioning (my previous sub position, at right side of rear of couch, raised off ground 2~ feet).

My sub is behind my couch at the center of the couch, driver about 2' from wall facing couch (it's on it's side, even though it's a down-firing sub). I have bass traps in front right and rear right corners of room (from left corner is door opening, and rear left is where the computer is, although I have a 2" panel there for echoes.

This was taken a long time ago and shows with and without my bass traps. The bass traps were in same location as they are now, but the whole room setup 90 degrees (wide across the narrower dimension of the room, with more depth to the room, now have projector screen on longer wall, turned 90 degrees).


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## tonyvdb (Sep 5, 2007)

In your case placement will be the key to getting it right. Have you tried it in the front corner of the room? Room reflection is a fun one to deal with and sometimes we just need to accept that it can not be perfect. I understand that the distance settings can make a difference (I know in my case it did not). In your case the settings changed the reflective points of the 90-150Hz range but that is the room reacting to the sub and not the sub its self.


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## cyberbri (Apr 27, 2006)

It actually used to be in the front right corner, and it had the same giant peaks, although not exactly the same. I moved it to behind the couch because I wanted more visceral slam without having to upgrade the sub itself.


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## tonyvdb (Sep 5, 2007)

What are the dimensions of the room? I had a look at your photos of the room, very nice.:T


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## cyberbri (Apr 27, 2006)

Thanks!

About 14' deep, and 18' wide at the rear, 23' wide at the front. The front door is in the rear right, hence the difference in widths, with a walkway on the left side of the room.


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## tonyvdb (Sep 5, 2007)

Its too bad you cant turn the room so the room is deeper rather than wide. That would help dramatically with how things sound.


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## glaufman (Nov 25, 2007)

Hmm... I too am confused by how the distance settings are actually affecting the curve right around the crossover. That being said, even with a 4th xover at 70Hz, the sub channel should only be about 10dB down from the mains at 90Hz. That being said, the sub only scan sure doesn't look like the xover is set to 70Hz.
But it sure does look like that peak at 72Hz is gone...


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