REW interpretation guidance

[RicD]

Hi Folks,
First post after a few weeks of reading.
I'd appreciate some guidance as to whether the REW measurements I performed warrant room treatment.

I recently updated my stereo in a different house.
I have an integrated amp (Simaudio 340) powering Monitor Audio gold 300 5g speakers.

I did some left and right speaker measurements using a calibrated UMIK-1 on a tripod at the listening position, aimed between the speakers.
The room dimensions are 11'6" x 21', with a height that is 7'3" at each end, peaking to 10' high in the middle of the length.

My main concern is the differences in what I recorded for the left vs right speaker.
The left speaker is near a couch and the wall along that side opens into another room.

I'll try to post some images.
I took two measurements for each of a variety of room and speaker arrangements, thinking that I may need to average them for each condition, but the results of the duplicate measurements are essentially identical.

The left speaker result has two dips between 50-70Hz, and the right speaker result has a peak at 300Hz. I changed the toe-in angle from nearly straight, to aimed at the listener with no significant difference. I took the ottoman out of the room, with some differences around 200Hz, see plot. I slid the couch 6" further from the left speaker, with little difference.

I welcome opinions on how significant my room issues are and if so, how easily they might be treated.
The system sounds good to me currently, especially for piano concertos etc.

Thanks!

Richard

Room

LvsR

effect of removing ottoman

 

[Miniyouuuu]

Untreated room with severe bass issues and quite unbalanced L/R channels due to asymmetric layout. Your problem is not the ottoman…
20-30hz on both channels is + 8dB which to me is a tad high. Good for cinema and usually not a problem for music because very few song reach these frequencies (current electronic bass heavy songs).
R channel remain almost stable +6/8 dB up to 100hz. High but coherent. I suggest a monster basstrap behind the speaker for more even and controlled 80hz bass.
L channel has a huge cancelation (up to -20dB) from 35 to 75hz. That range is really complex to fix. No basstrap can help, you need a sub strategically located to fill that cancellation but be aware where you put it. And symmetric monster basstrap will help to create a more even soundstage.

Comparing both sides, on the right you have a large shelve with many books and little partition that help difraction of sound.
On the left white wall with no difraction, pure reflection and a coach in the lower part that can have some absortion.

You can play with toeing, and moving the speakers, but I suggest 2 o more monster bass traps (more than 150mm depth) behind the speakers, some difraction on the white wall and 1 subwoofer located in the middle o wherever does improve your symmetry of sound and fills the huge cancelation at 40/70hz

Did you considered locating the speaker in front of the shelve? At least you could enjoy music from the coach and shelve will help an even dispersion of sound. Your actual layout is solely focus on music, while TV is in the perpendicular axis. You could have both in the same axis.

 

[kyuu]

Welcome to ASR! One thing I can tell you is that our measurement gurus usually like it if you attach the .mdat to your post so they can see the full suite of measurements for themselves. It's also helpful if you label all your graphs and include the labels in your screenshots. For example, without further context it would be difficult to know what the two lines on your first graph are.

One thing I might recommend trying is moving your speakers closer to the wall (the one behind them) and taking the measurements again to see what, if any, difference that makes. It's likely the large cancellation on the left speaker is due to room modes though. Your best bet for fixing issues in the bass is generally (a) subwoofer(s) and DSP.

 

[RicD]

Thank you both for your time and insights.
I hesitated to load the .mdat file since it contains 18 poorly labeled measurements. It was my first time getting it working, so I'd need to prepare one that's better organized.
My hope/fear was that the Lspk bass dip was a glaring issue and I could get some initial feedback based on that plot.

One clarification: the photo does make the speaker placement appear asymmetrical, but they are placed following a guideline on the Cardas site, and are actually both about 38" from the sides, and just over 4' from the back.

Changing the toe-in significantly made essentially no change to the measurements, so I'll undo that and test moving them back towards the back wall while I'm at it. I don't think I can rearrange the room to place them on the long wall.

I initiated a consultation with GIK, but appreciate the advice received here, since I imagine that a company selling room treatment will always find things to suggest.

Based on your comments it seems likely that I'll end up with bass traps and perhaps a diffuser.

Thanks!

 

[Miniyouuuu]

Perfectly symmetric layout with reflecting walls that have very different absortion and diffusion values will affect the perceived symmetry at the sitting spot. Direct sound is important, but close walls will affect very hard.

Do you listen to music from the ottoman or from the coach? Because the coach has a horrible disposition for sound.

 

[RicD]

I sit in the recliner visible on the lower right of the room photo. The speakers are 5'6" apart, and my head is 8'6" straight back. I think the toe-in is 18 degrees.

 

[Mort]

That's quite far back. The ideal is about 4'9" straight back with speakers that far apart . The stereo image might be messy from that far. Toe in could make it worse.

 

[RicD]

Thanks, I'll try moving it way in, though I'll have to move it back when others are watching the TV...

 

[RicD]

I moved both speakers back so that the front of them is 36" from the back wall, and reduced the toe-in. The difference seems pretty dramatic for the left speaker, compared to yesterday's placement. The huge dip between 50-70Hz is now a peak, although a new dip appears just below 100Hz. I don't know whether to be optimistic about further adjustments, or concerned about how sensitive it is. The third image is L vs R in the current configuration.

 

[Ruhled]

That repositioning really helped that lf dropout. Narrow peaks are less audible than wider ones, all things being equal, so keep trying you might be able to get it even better. Move the ottoman around too. I've found my room is much easier to correct when I use a loveseat vs a chair in the same listening position, so all that stuff matters! People that move furniture out of the room to measure are doing it wrong IMHO.

 

[RicD]

Thanks, yes, I will try some more adjustments. Mentally interpolating between the results from yesterday and today, I think I'll undo about 25% of the move.

 

[RicD]

Last update for now.
I had moved the speakers from 48" from the wall, to 36" and seen an improvement. I guessed that slightly less adjustment might be better and brought them out to 39", but it was worse. Finally I went even further, to 32" and got a result that I'm happy with, at least until I add room treatment.

The first plot shows the left speaker result at 4 different positions, and the second plot shows L (blue trace) vs R at the 32" that I've settled on for now.

 

[Marin]

Monitor Audio gold 300 5g speakers

https://www.stereophile.com/content/monitor-audio-gold-300-loudspeaker
Is this the same speaker's?

 

[RicD]

That article says fifth generation, so yes, that should be the one I got.
There is a new g6 out now which is why I could just about afford these.

 

[Marin]

That article says fifth generation, so yes, that should be the one I got.
There is a new g6 out now which is why I could just about afford these.

Wow
Really is beautiful looking speaker.
The measurements are some of the better ones I've seen in Stereophile.
Congratulations on a good choice.

 

[RicD]

Thanks, they do sound great. I had a great experience at a local dealer. They let me audition various speakers, powered by the same amp I have at home, and even got out a tape measure to roughly match my listening position at home. I was handed an ipad to stream familiar recordings.
Of course the room is quite different as I'm working on now.

 

[Marin]

Last update for now.
I had moved the speakers from 48" from the wall, to 36" and seen an improvement. I guessed that slightly less adjustment might be better and brought them out to 39", but it was worse. Finally I went even further, to 32" and got a result that I'm happy with, at least until I add room treatment.

The first plot shows the left speaker result at 4 different positions, and the second plot shows L (blue trace) vs R at the 32" that I've settled on for now.

First measurements is better looking one.
I would move your seating position for better ratio direct-reflect sound.
Easier than moving speakers.
Especially if you like the boost you get in the subbase?
Right now you listen mostly reflections... Basically your room instead of speakes.
Also notice how much high frequencies eat that couch and bookshelf.
You can't have effect of toe in,or stereo imaging that far away... you see that highs don't change and it should be if you create stereo equilateral .
I still don't get how much subbase you get without Sub?

 

[RicD]

First measurements is better looking one.
I would move your seating position for better ratio direct-reflect sound this way you get mostly or maybe the speakers if you listen reflection basically your room instead of speakes.
Also notice how much high frequencies eat that couch and bookshelf.
I still don't get how much subbase you get without Sub?

Sorry, which measurement are you saying looks best to you?
I'm looking into some room treatment from GIK, so hopefully the room will be improved somewhat.

 

[Marin]

Sorry, which measurement are you saying looks best to you?
I'm looking into some room treatment from GIK, so hopefully the room will be improved somewhat.

This looks good to me.
How is the ratio between bass and higher tones?
The most important thing is how they sound to you.
Is it high-low tone ratio balanced while you listen to your music?

 

[Marin]

Sorry, which measurement are you saying looks best to you?
I'm looking into some room treatment from GIK, so hopefully the room will be improved somewhat.

I say again, it's a shame you don't listen to that great AMT twitter.

Your room basically dumpend that great little air motion tweater.
Did you try listening 1,5 meter away, because that is the right distance if they are about 2 meters away and not much toe in.15-20 degree looks fine.