1st REW SubWoofer measurements

[PG55]

Hello,

This my 1st attempt at taking measurements of my 5.1 system and I could use some guidance. I am not sure which speakers I should be measuring and how I should group them for the measurements. I took a few measurements of my Sub Woofers (attached) and would appreciate some feedback if you can interpret these measurements and provide some guidance on how best to measure going forward to optimize my room and suggestions on sub placement given these measurements.

My room is 18WX20L > long side opening into the kitchen. I have 12 foot vaulted ceilings. I have 2 subs as you can see from the measurements. They are Paradigm Millenia subs and shaped like a small suitcase so they are versatile with placement under and next to furniture. Sub 1 is in the front middle under the center channel and Sub 2 is in the middle of the back wall.

Thanks,
PG55.

 

[shadyJ]

First of all, try to have a consistent window that we can see your measurements in. Try sticking with a Y-axis of 50 dB to 100 dB, and an X-axis of 15 Hz to maybe 200 or 250 Hz. It looks to me like you get a pretty decent response with both subs together, although there is a bump from around the lower 50 Hz range which extends to the low 60 Hz range that could use a trim.

Run a sweep with both subs playing at the same time to see what happens.

 

[MalVeauX]

Heya,

I would alter your limits (top right icon with arrows in all directions) so that your image scale is more appropriate to the resolution of your measurement so that you can see meaningful information. Isolate your subwoofer and do not have it joining the mains & surrounds when doing its measurement so you can see its individual room response and get it's placement in the room as best as you can via measuring room response with it. Then after that, do a full sweep and blend into your main system. Then when you do a final sweep on the sub, do 10hz to 200hz and take a look. Again, room placement is key, and the measurement you're doing on the sub is actually room response not the speaker's actual output out of context of the room. So correct it via placement ideally first. Then you can do an EQ to fix anything else that isn't a major null.

Here's an example of room response followed by EQ to get a lovely flat response curve for bass (and this is my mains, not my subs):

Very best,

 

[shadyJ]

Heya,

I would alter your limits (top right icon with arrows in all directions) so that your image scale is more appropriate to the resolution of your measurement so that you can see meaningful information. Isolate your subwoofer and do not have it joining the mains & surrounds when doing its measurement so you can see its individual room response and get it's placement in the room as best as you can via measuring room response with it. Then after that, do a full sweep and blend into your main system. Then when you do a final sweep on the sub, do 10hz to 200hz and take a look. Again, room placement is key, and the measurement you're doing on the sub is actually room response not the speaker's actual output out of context of the room. So correct it via placement ideally first. Then you can do an EQ to fix anything else that isn't a major null.

Here's an example of room response followed by EQ to get a lovely flat response curve for bass (and this is my mains, not my subs):

View attachment 36969

Very best,

That is not a lovely flat response, that is 1/3rd octave smoothing. Post that measurement with no smoothing if you are man enough!

 

[MalVeauX]

That is not a lovely flat response, that is 1/3rd octave smoothing. Post that measurement with no smoothing if you are man enough!

Fair point, I will have to re-measure as I didn't keep the data file. It was similar though, I didn't have any major nulls and nothing past +/- 3~4db really. But again, you make a fair statement. My other points stand unless you disagree.

Very best,

 

[lovinthehd]

Also consider multiple mic positions and using an averaged response. Or is that already what we're looking at?

 

[MalVeauX]

Also consider multiple mic positions and using an averaged response. Or is that already what we're looking at?

Averaged response from multiple listening positions. Nothing special. I do not have special gear. I just note that a well treated room with good placement has a huge effect on low frequencies, since its mostly room response and not just "quality" of the speaker itself.

Not trying to distract from the spirit of this thread; just was trying to point out that excellent response can be had if care is taken with the room.

Very best,

 

[PG55]

Here is my room. I don't know where to start?

Heya,

I would alter your limits (top right icon with arrows in all directions) so that your image scale is more appropriate to the resolution of your measurement so that you can see meaningful information. Isolate your subwoofer and do not have it joining the mains & surrounds when doing its measurement so you can see its individual room response and get it's placement in the room as best as you can via measuring room response with it. Then after that, do a full sweep and blend into your main system. Then when you do a final sweep on the sub, do 10hz to 200hz and take a look. Again, room placement is key, and the measurement you're doing on the sub is actually room response not the speaker's actual output out of context of the room. So correct it via placement ideally first. Then you can do an EQ to fix anything else that isn't a major null.

Here's an example of room response followed by EQ to get a lovely flat response curve for bass (and this is my mains, not my subs):

View attachment 36969

Very best,

I will follow your process as described and post the results. I have been told my room is very challenging acoustically. See Attachment.

 

[MalVeauX]

It looks like you will not have a lot of options for placing anything, other than wiggling small amounts in its current position. Granted, 2" can make a difference so it's worth moving it around a little bit to see what the room response is. A challenging room it probably is, slanted ceiling, brick, wood, lots of hard surfaces. You could do room treatment, but it doesn't look like a room that you'd want things on the walls.

Very best,

 

[William Lemmerhirt]

Fair point, I will have to re-measure as I didn't keep the data file. It was similar though, I didn't have any major nulls and nothing past +/- 3~4db really. But again, you make a fair statement. My other points stand unless you disagree.

Very best,

Iirc rew auto saves. So when you open it, I think you go up to “file” and it should be in there. I think...been a little while.

 

[MalVeauX]

Any updates from the O.P., @PG55 ?

Following up...

My better half rearranged furniture with the kids, so had to remeasure anyways, worked out either way. I wiped everything and started from scratch. Just the mains, nothing else, no sub. This is 10hz to 400hz to represent room response. Was targeting reference +/- 5db. Looks like I have a trough up in 250hz range to fix up. But from there down it looks good for a living room (not a dedicated room). 25hz sounds pretty good, despite no sub. Not as strong as a 112db 25hz from a sub, but for every day, this is where my living room is at. Anyhow, just following up to before. This was smoothed to 1/6th octave as standard to reveal any booboos and is indeed "less lovely." But it tells me where to start looking to treat/correct for the room.

Very best,

 

[PG55]

@MalVeauX - I will be working on it tonight. I was having issues with ASIO4ALL but I think I have it figured out so I should be able to run some frequency tests on the Sub, tonight.

Thanks,
PG55

 

[Pogre]

Heya,

I would alter your limits (top right icon with arrows in all directions) so that your image scale is more appropriate to the resolution of your measurement so that you can see meaningful information. Isolate your subwoofer and do not have it joining the mains & surrounds when doing its measurement so you can see its individual room response and get it's placement in the room as best as you can via measuring room response with it. Then after that, do a full sweep and blend into your main system. Then when you do a final sweep on the sub, do 10hz to 200hz and take a look. Again, room placement is key, and the measurement you're doing on the sub is actually room response not the speaker's actual output out of context of the room. So correct it via placement ideally first. Then you can do an EQ to fix anything else that isn't a major null.

Here's an example of room response followed by EQ to get a lovely flat response curve for bass (and this is my mains, not my subs):

View attachment 36969

Very best,

I do not use any smoothing when I'm calibrating. It doesn't look as nice but too much smoothing hides problem spots. When I get everything as good as I can I'll go to 1/12 smoothing to pretty it up a little bit.

 

[Pogre]

Any updates from the O.P., @PG55 ?

Following up...

My better half rearranged furniture with the kids, so had to remeasure anyways, worked out either way. I wiped everything and started from scratch. Just the mains, nothing else, no sub. This is 10hz to 400hz to represent room response. Was targeting reference +/- 5db. Looks like I have a trough up in 250hz range to fix up. But from there down it looks good for a living room (not a dedicated room). 25hz sounds pretty good, despite no sub. Not as strong as a 112db 25hz from a sub, but for every day, this is where my living room is at. Anyhow, just following up to before. This was smoothed to 1/6th octave as standard to reveal any booboos and is indeed "less lovely." But it tells me where to start looking to treat/correct for the room.

View attachment 37000

Very best,

Do you have a MiniDSP also, or are you using room correction and positional eq? No sub in the mix?

 

[MalVeauX]

Do you have a MiniDSP also, or are you using room correction and positional eq? No sub in the mix?

I don't have a MiniDSP, I wish I did. I will eventually get one later this year to work with 4 subs. For now, no though. The above has no subwoofer in the mix. That's strictly my left and right mains in stereo in my living room. Furniture moved significantly yesterday, so it was good to re-run everything to see how it changed. No room correction from the AVR. Simply running REW to see the response and altering position of speakers as I can (within reason of the room) and then if I want to do a little EQ to it, I do that to try to get closer to a house curve.

I'm fairly new still to measuring and interpreting graphs as I just got my mic recently and I'm enjoying finally putting metrics to what's going on in the room. It really is an eye opener. I have stopped using my sub(s) in the living room for now, just seeing what the experience is like with movies, shows, games with the family and the measurement and the listening experience seem to correspond, the low end sub-bass is quite good. When running a sub I like to run it a bit hotter than the rest, as do most, for movies, but for general use I don't feel the need to turn on my subs day to day if not watching a specific movie in the living room.

Very best,

 

[Pogre]

I don't have a MiniDSP, I wish I did. I will eventually get one later this year to work with 4 subs. For now, no though. The above has no subwoofer in the mix. That's strictly my left and right mains in stereo in my living room. Furniture moved significantly yesterday, so it was good to re-run everything to see how it changed. No room correction from the AVR. Simply running REW to see the response and altering position of speakers as I can (within reason of the room).

Very best,

We work with what we have. Most don't care enough to even bother with measuring. I didn't see which avr you have, but I've found running room correction (Audyssey MultEQ XT32) does help flatten my response. Audyssey does a really good job with peaks especially.

 

[William Lemmerhirt]

@MalVeauX - I will be working on it tonight. I was having issues with ASIO4ALL but I think I have it figured out so I should be able to run some frequency tests on the Sub, tonight.

Thanks,
PG55

I would recommend not using asio. It’s a pain and unnecessary.

 

[MalVeauX]

We work with what we have. Most don't care enough to even bother with measuring. I didn't see which avr you have, but I've found running room correction (Audyssey MultEQ XT32) does help flatten my response. Audyssey does a really good job with peaks especially.

It's a Yamaha, nothing special, 100wpc 8ohm at 2 channel. In the living room we don't have a surround, it's just for TV, games and some movies (kids mostly). Nothing serious in there. But I like to use it for measuring because its a complex room, a living room, with a family, not a dedicated room. I'm soon to build a house and will gain a dedicated larger room, so practicing on learning how to measure, interpret and treat or correct so that I can get the most out of things. The mains on that living room setup are some 15 year old Monitor 70 II's, inexpensive, but sound good when placed and corrected.

With multiple subs, its eye opening to measure. Something the room correction softwares on the AVRs don't seem to do well enough.

My primary listening room (music) currently is a 2 channel setup without an AVR, just stereo integrated amp with bookshelves and I do run a sub with those. Some old Monitor 30 II's and a PSW505, again, nothing special at all, stuff I got 15 years ago before kids. I had a lot of fun measuring that system and manually tweaking everything and blending since it has no processor doing any of that.

Very best,

 

[Pogre]

It's a Yamaha, nothing special, 100wpc 8ohm at 2 channel. In the living room we don't have a surround, it's just for TV, games and some movies (kids mostly). Nothing serious in there. But I like to use it for measuring because its a complex room, a living room, with a family, not a dedicated room. I'm soon to build a house and will gain a dedicated larger room, so practicing on learning how to measure, interpret and treat or correct so that I can get the most out of things. The mains on that living room setup are some 15 year old Monitor 70 II's, inexpensive, but sound good when placed and corrected.

With multiple subs, its eye opening to measure. Something the room correction softwares on the AVRs don't seem to do well enough.

My primary listening room (music) currently is a 2 channel setup without an AVR, just stereo integrated amp with bookshelves and I do run a sub with those. Some old Monitor 30 II's and a PSW505, again, nothing special at all, stuff I got 15 years ago before kids. I had a lot of fun measuring that system and manually tweaking everything and blending since it has no processor doing any of that.

View attachment 37009

Very best,

That looks pretty nice!

As far as AVRs not working well it depends on the RC software. Audyssey XT32 can set levels and phase independently for 2 subs and really does a pretty good job for me. I have a complex room too. It's good sized, open to another room on the right, a hallway and vaulted ceilings. I do have a nasty null that Audyssey struggles with but I can coax it the rest of the way with my mini. Here's a before and after sweep I did with my Ultra towers by themselves (no subs).

The green trace is the "before" with no room correction and blue is "after". The target is ~80 dB at that volume and it's significantly better (no smoothing), especially with taming the peaks. Still not quite there, but I'll bet it'd look a lot better with 1/3 smoothing!

 

[MalVeauX]

That looks pretty nice!

As far as AVRs not working well it depends on the RC software. Audyssey XT32 can set levels and phase independently for 2 subs and really does a pretty good job for me. I have a complex room too. It's good sized, open to another room on the right, a hallway and vaulted ceilings. I do have a nasty null that Audyssey struggles with but I can coax it the rest of the way with my mini. Here's a before and after sweep I did with my Ultra towers by themselves (no subs).

View attachment 37010

The green trace is the "before" with no room correction and blue is "after". The target is ~80 dB at that volume and it's significantly better, especially with taming the peaks. Still not quite there, but I'll bet it'd look a lot better with 1/3 smoothing!

Looks good, that null at 45~46hz probably cannot be fixed even with the miniDSP or correction though, that's likely the room itself, you'd have to move the speakers physically to correct/improve that I think? The big mode next to it is nearly 12db delta followed by a pretty significant null. Granted, I imagine your subs cover that up so it doesn't matter likely. Still learning.

Very best,