FR as to LCR & Subwoofer

[kgveteran]

I have been running sweeps using TruRta for the last few hours and trying to get my mains (LCR) flat. After some tweaking at the XO point (100hz) I have really got it flat with the exception of a null between 44hz and 56hz , about -6db.When I smooth out the response to 1/3rd oct it is ruler flat.

I started with the subwoofer.I ran sweeps and really only found one peak centered at 34hz and cut by -10db (not sure of the width on the cut).Once that was done and the response looked good I started on the center without the sub.I worked on the XO point.The center had a rise below the XO point that gave the sound a bit of a "chesty sound".I did all this with an Ashly analog PEQ.I ran one sweep with the subwoofer in, and the response was perfect.I then did the mains the same way.First without the sub to get an idea of the response at the XO point and adjusted for that.So now the mains are set along with the subwoofer.

What are your thoughts on the method of my work.I like the way it "Looks". I'll give it a whirl with some movies and music DVD's to see if I like the "Flat" sound.

Now the surrounds and I'm done......ya..done :B

[Kal Rubinson]

Two questions: Where did you put the microphone and did you try more than one site?

Kal

[kgveteran]

I have a sofa recliner that hold three adults.I put the mic where our heads would be in the relined position.I ran sweeps in all three places.They all were different , but just slightly.

I think this is a problem with the processor, but the right main is about 2db off from the left.I have an Outlaw 990, and have read this before.

As of now the mains are vertical.They shouldn't be.I use three RS centers as mains.I'm getting new stands that will raise them up and orient them on their sides where they belong so the tweeters and midranges are vertical like the center channel is.

I was just wondering if this method is right.I started with the center and then blended the sub in at the XO point. The center sounds better than the mains because of the horizontal orientation.Can't wait to get my stands.

KG

[Kal Rubinson]

I am surprised that you don't find lots of varying nodes/nulls with different microphone positions. That is highly unusual.

Kal

[kgveteran]

I setup the speakers on a 1/5th point and the head position on the sofa is on a 1/3rd position in the room.

It took quite a bit of moving and sweeping with TruRta to get things flat.I do have the 50hz issue, but that isn't very wide.

The subwoofers seem to only have one problem and one filter fixed that.

One issue with the monitors is I have to give them a little dip around 2k.I like the BBC curve.I have to be very careful to do each speaker one at a time and not too much and not too wide.Thats a taste thing though.

I only use three positions when running sweeps.Those are the three head positions on the sofa.

[Kal Rubinson]

OK. I've found that one can get quite varying measurements by moving the microphone 2-4" even though I can replicate the same measurements at other positions on the couch. EQ-ing the FR for the "matching" positions on the couch does not have the same effect at the intermediate positions. What I am saying is that, unless the head is rigidly fixed, the ears are sampling different effects. Assuming you have a substrate of a decently treated acoustic environment, of course, these effects can be minimized.

Kal

[kgveteran]

OK. I've found that one can get quite varying measurements by moving the microphone 2-4" even though I can replicate the same measurements at other positions on the couch. EQ-ing the FR for the "matching" positions on the couch does not have the same effect at the intermediate positions. What I am saying is that, unless the head is rigidly fixed, the ears are sampling different effects. Assuming you have a substrate of a decently treated acoustic environment, of course, these effects can be minimized.

Kal

Oh, lets put it this way....I end up with a smoothed 1/3rd response.I would agree that there are variation, but when I smooth it out it looks quite similar.

[Kal Rubinson]

Oh, lets put it this way....I end up with a smoothed 1/3rd response.I would agree that there are variation, but when I smooth it out it looks quite similar.

Ha. I know that drill. The narrow-bandwidth variations are always there. If they disappear with the 1/3 or 1/6 octave smoothing, they probably are minor. Besides, perfection is elusive.

OTOH, did you do any spectral decay measurements? I've been fooling with many measurement and/or correction devices and there are some really narrow-bandwidth modes with extended decay and getting rid of those makes for a significant subjective improvement.

Kal

[kgveteran]

Ha. I know that drill. The narrow-bandwidth variations are always there. If they disappear with the 1/3 or 1/6 octave smoothing, they probably are minor. Besides, perfection is elusive.

OTOH, did you do any spectral decay measurements? I've been fooling with many measurement and/or correction devices and there are some really narrow-bandwidth modes with extended decay and getting rid of those makes for a significant subjective improvement.

Kal

Spectral decay would be time based anomalies? Thats all I have now is TruRta.I'm stuck with FR software for now.I would like to see how my room treatments work, what software do you use.

I use to kill myself trying to manage 1/24th oct...Wow..too many jaggies for me! And I'm hoping too many for my ears too.

[Kal Rubinson]

Spectral decay would be time based anomalies? Thats all I have now is TruRta.I'm stuck with FR software for now.I would like to see how my room treatments work, what software do you use.

I use to kill myself trying to manage 1/24th oct...Wow..too many jaggies for me! And I'm hoping too many for my ears too.

1/24th octave is the way to go for the EQ measurements! In any case, download RoomEQ Wizard for time-based measurements. You may change which frequencies you choose to fix.

Kal

[kgveteran]

Kal,
My learning curve is huge.I'll have to read a bit before this all sinks in.