First REW Measurements-Newbie REW Graph Interpertation- Help me interpret

[tjm2]

You could leave them where they are and see what effect blocking the ports with some foam or a washcloth has.

I will expereiment and see what happens. They also have switches to adjust the Low, Mid and High frequency. I can lower low frequency by -4db, maybe I'll do that and see what effect it has. Is the idea to get the area between 40Hz and 80ishHz to be more in line with the rest of the response?

 

[raindance]

I will expereiment and see what happens. They also have switches to adjust the Low, Mid and High frequency. I can lower low frequency by -4db, maybe I'll do that and see what effect it has. Is the idea to get the area between 40Hz and 80ishHz to be more in line with the rest of the response?

Ideally you want a gentle downward slope from the low frequencies to the high frequencies, but yes, you don't want anything "sticking up" above anytime else.

 

[SIY]

I will expereiment and see what happens. They also have switches to adjust the Low, Mid and High frequency. I can lower low frequency by -4db, maybe I'll do that and see what effect it has. Is the idea to get the area between 40Hz and 80ishHz to be more in line with the rest of the response?

Job One: make those interference dips as innocuous as possible.

Get the mains right first. Get the mains right first. Get the mains right first. Stop worrying about bass extension until you get the response smoother.

 

[tjm2]

Job One: make those interference dips as innocuous as possible.

Get the mains right first. Get the mains right first. Get the mains right first. Stop worrying about bass extension until you get the response smoother.

Aye Aye Captian! I think I am understanding now that changing those things (putting dirty clothes in the ports, adjusting the levels of Low frequencies) will not affect smoothing the frequency of the mains.

 

[SIY]

Aye Aye Captian! I think I am understanding now that changing those things (putting dirty clothes in the ports, adjusting the levels of Low frequencies) will not affect smoothing the frequency of the mains.

Yes, this is almost certainly a question of positioning in the room.

 

[Salt]

Yes, this is almost certainly a question of positioning in the room.

Yes, this is all about to teach someone absolutely untouched of anything about sound reproduction at all, by highly educated persons.
Tell me the place on this earth where you will get this for free?:

 

[tjm2]

Yes, this is all about to teach someone absolutely untouched of anything about sound reproduction at all, by highly educated persons.
Tell me the place on this earth where you will get this for free?:

I played around with speaker positioning tonight for a few hours after work today. I think I made some progress. I'm sure I have created more issues but I think I got some of that bass shelf ( I think thats what you called it) down a bit. The other dips I'm struggling with. Let me know what you think, I tried a ton of positions and think this one appears decent to my untrained eye.

I surely appreciate the knowledge you are parting with to help me get some great sound from my system. How about I teach you about what I'm highly trained in (human teeth) and you teach me about sound reproduction?

Ive attached a screen shot and a link to the .mdat files.

Let me know what you think?

New vs Old positon.mdat

drive.google.com

 

[sam_adams]

Let me know what you think?

You are measuring the L + R speakers together. This is great if you wish to demonstrate comb filtering, but far from useful when trying to determine the frequency response of your speakers. Your measurements lack an acoustic timing reference. Without that, evaluating the response of the subwoofer(s) and their interaction with the L + R speakers will be extremely difficult.

Check and set the levels of the left and right speakers using the pink periodic noise signal. Check and set the level of the subwoofer using the subwoofer pink periodic noise signal. Set the levels to 75 dB or at least 30 dB higher than the noise floor of the room.

Use the acoustic timing reference for all measurements—all the time. Comparisons of impulse responses of the speakers—which will reveal the relative timing/distance differences between them—is impossible without a common timing reference.

Once your levels are set for all speakers, select which channel you wish to use as the timing reference for all measurements. Then measure the left speaker alone. Then measure the right speaker alone. Then measure the subwoofer alone. Then measure the left speaker with the subwoofer. Then measure the right speaker with the subwoofer. Responses can then be combined and compared using the various trace arithmetic functions in REW. Remember, meaningful comparisons of measurements cannot be made without a timing reference.

Answers to questions regarding many of the functions of REW can be found in the REW help files.

 

[Keith_W]

Your new position looks much better. Keep experimenting.

 

[raindance]

Try plugging the ports. It costs you nothing. It should remove the large peak. Of course I'm sure someone will come along and tell you to ignore that.

 

[Ruhled]

Turn on the high pass filter and I bet you can get rid of most of all of that peak.

 

[tjm2]

Try plugging the ports. It costs you nothing. It should remove the large peak. Of course I'm sure someone will come along and tell you to ignore that.

I know, sometimes it is overwhelming on the forums - like a firehose of information and its easy to get lost in what is best for your situation. I'm a tinkerer (I think like most of us) and love learning, but can get obsessed with perfection and forget why I like this hobby- to enjoy music and escape for a little while.

I played around with the REW room simulation and put speakers and listening position in a new location with those recommended measurements. To my ears it sounds much better and less bass heavy.

I did not plug the port but I lowered the Low frequency setting on the speaker by -4 (it has a setting as they are powered speakers). It definitely takes out that peak. I have attached both with the -4 setting engaged and flat in the new positions.

Ive attached the newest REW report.

New positions and Flat and -4 LF settings.mdat

drive.google.com

 

[Ruhled]

Maybe show same measurement with variable smoothing as well?

 

[tjm2]

Maybe show same measurement with variable smoothing as well?

Here it is with Variable smoothing

 

[Ruhled]

Where is your mic positioned and is it on a boom or tripod? The 10db waviness around 1khz seems a bit much. I'd be tempted to try just a bit of a cut on the mid just to see the effect of that. The bass looks much nicer though. You can "season to taste" from there with bass control.

 

[tjm2]

Where is your mic positioned and is it on a boom or tripod? The 10db waviness around 1khz seems a bit much. I'd be tempted to try just a bit of a cut on the mid just to see the effect of that. The bass looks much nicer though. You can "season to taste" from there with bass control.

It is on a mic stand. My listening position is on a couch center seat. I have it behind the couch holding the mic at ear level in my spot.

 

[Salt]

At first glance with your modification the FR is almost as perfect as can be down to 40 Hz and then decays with 24 or more dB/octave.
If a sub really is needed below this, this should LP at 40 Hz or less with 4'th order or higher.
And keep in mind delay and phase.
It's all not as simple as estimated ...

 

[RayDunzl]

Downloaded NewVsOldPositon.mdat

Impulse response, using % for the graphing..

Mine is Black, yours are red and blue.

Whats going on in your room, to create what looks like a jumble of reflected sound?

 

[SIY]

Whats going on in your room, to create what looks like a jumble of reflected sound?

That's something you see a lot when you measure both speakers simultaneously. Move the mic a little, and the jumble changes accordingly.

 

[RayDunzl]

My measurement was for both speakers.

Here is my L/R/Both, from the listening position.