What speaker would you choose and what are those dips

[Duper]

Hello,
Based on the frequency response below, would you choose speaker A or B for the LR speakers in the 5.1 system. Both speakers were crossed at 80hz to the sub at the receiver. Measured at MLP
Also, what are those big dips at about 350hz and 2khz regions? Must be room modes? Any way to improve them?

Here is the sketch of the living room. 8ft ceiling height.

thanks for your input

 

[AudiocRaver]

Are you measuring with the L and R speakers both running at the same time? If so, you will most likely get horrendously inaccurate results, mainly at higher frequencies, but potentially affecting down into the mids, too.

 

[Duper]

Are you measuring with the L and R speakers both running at the same time? If so, you will most likely get horrendously inaccurate results, mainly at higher frequencies.

No, I measured only Left channel and by physically swapping the speakers.

 

[AudiocRaver]

Good.

The highly reflective wall on the left will cause a reflection/cancellation problem, as will the mirror behind the listening position. Some call his phenomenon "boundary interference." These could be causing the big dips you refer to, A floor reflection could be involved, too.

Beyond that, it is tough to say how the sound of the two speakers compare just from the measurement shown..

 

[AudiocRaver]

Scuse me, just noticed you included the mdat file, I will take a closer look after dinner.

 

[AudiocRaver]

Looking at the impulse response, and estimating distances from your diagram, it looks like the reflection off the glass side wall might be causing the 300 to 400 hz dip (1.3 ms delayed reflection on impulse diagram), and the reflection off the side wall to back mirrored wall might be causing the 125 hz dip (3.8 ms delayed reflection on impulse diagram), and the reflection directly off the mirror to the LP might be causing the 185-ish hz dip (2.6 ms delayed reflection on impulse diagram).

I'm going to go with speaker B with port plug, less boominess in the bass around 100 to 150 Hz and better/smoother midrange presence above 2 kHz. This could change with other changes in the room, like...

The couch should be out from the wall and so should the speakers for better soundstage and imaging (SS&I). Replace the mirror with an absorptive panel and add thick drapes that can be drawn closed to cover the side window while listening. All subject to WAF (wife acceptance factor) of course.

That's my 2cents worth.

 

[Duper]

Looking at the impulse response, and estimating distances from your diagram, it looks like the reflection off the glass side wall might be causing the 300 to 400 hz dip (1.3 ms delayed reflection on impulse diagram), and the reflection off the side wall to back mirrored wall might be causing the 125 hz dip (3.8 ms delayed reflection on impulse diagram), and the reflection directly off the mirror to the LP might be causing the 185-ish hz dip (2.6 ms delayed reflection on impulse diagram).

I'm going to go with speaker B with port plug, less boominess in the bass around 100 to 150 Hz and better/smoother midrange presence above 2 kHz. This could change with other changes in the room, like...

The couch should be out from the wall and so should the speakers for better soundstage and imaging (SS&I). Replace the mirror with an absorptive panel and add thick drapes that can be drawn closed to cover the side window while listening. All subject to WAF (wife acceptance factor) of course.

That's my 2cents worth.

Thanks for your input AudiocRaver. I see your point about speaker B with port closed. However, when looking at the waterfall (not that I understand a lot) for the speaker B with port closed, it looks like it has the highest and longest lasting peaks out of all 3 measurements, continuing past 1Khz. Is this something that I should be concerned? Are they created by the port being closed?

Moving couch away from the wall is not an option in an already small Livingroom. Speakers, maybe I could move 1" away from the wall but any more than that.

 

[AudiocRaver]

Good question, I just looked at the waterfalls now. The "speaker b with port plug" measurement has a very high noise floor, that's what you are seeing in the waterfall. Take a look at the distortion diagram and it stands out very clearly. A re-take of the measurements is in order before making any decisions, taking care about noise sources. When in doubt, it is a good practice to glance at the distortion diagram after each measurement. It's an easy way to see if the noise floor is at an acceptable level. It is not uncommon for noises to be picked up that are easily missed if you are not listening for them with eagle ears. With practice you will develop your talent for hearing the noises that mess up the integrity of a measurement. Watching the little sonogram plot on the measurement panel during the sweep will help you catch them in real time.

 

[ddude003]

It does not look like the two different speakers matter much... The room is the problem... I would be tempted to set up the tv and stereo where the sofa currently sits... Center the system and speakers on that wall... The mirror wall needs base traps in the corners and a wide band absorber or two across that wall... Put the sofa where the tv is and get it off the wall by a foot or more, please add a wide band absorbers behind it... If you do EQ push peaks down... The the rest you will go crazy trying to push up... Just don't... Other than that... I agree with @AudiocRaver 100%...

 

[Duper]

Good question, I just looked at the waterfalls now. The "speaker b with port plug" measurement has a very high noise floor, that's what you are seeing in the waterfall. Take a look at the distortion diagram and it stands out very clearly. A re-take of the measurements is in order before making any decisions, taking care about noise sources. When in doubt, it is a good practice to glance at the distortion diagram after each measurement. It's an easy way to see if the noise floor is at an acceptable level. It is not uncommon for noises to be picked up that are easily missed if you are not listening for them with eagle ears. With practice you will develop your talent for hearing the noises that mess up the integrity of a measurement. Watching the little sonogram plot on the measurement panel during the sweep will help you catch them in real time.

I looked at the Distortion tab. From what I have read before I should be looking at 3rd Harmonic and THD. Is that correct procedure? Can you explain what those graphs mean? It is very possible that the car was driving near by when I took the measurement. I do live near busy road.
To add to your comment "it looks like the reflection off the glass side wall might be causing the 300 to 400 hz dip " when I was taking measurement I did had the sliding door closed to minimize outside noise. However, 95% of the time when I am listening to the audio system the sliding door is open. I will take another measurement with the door open to see if this dip goes away of is the reflection is still there. the room noise will be much higher but it will represent more realistic listening situation.

 

[Duper]

It does not look like the two different speakers matter much... The room is the problem... I would be tempted to set up the tv and stereo where the sofa currently sits... Center the system and speakers on that wall... The mirror wall needs base traps in the corners and a wide band absorber or two across that wall... Put the sofa where the tv is and get it off the wall by a foot or more, please add a wide band absorbers behind it... If you do EQ push peaks down... The the rest you will go crazy trying to push up... Just don't... Other than that... I agree with @AudiocRaver 100%...

Thanks for your input, that will make my speaker selection much easier if you also think that both speakers are about the same. It is absolutely not the option so switch the room around. Just so I have an idea, how would switching the room help to improve the audio? Unfortunately Base traps out of the scope too as this is a living room and wife will not approve. I did get temporary approval to put some make shift diffuser/absorber on the mirror wall to if it will make any difference. More importantly will there actually be any difference that we can hear. I do not have any option to push the peaks down other than mini-dsp for the subwoofer. Which is already pushing massive peaks at 50hz.

 

[ddude003]

I thought your Onkyo had EQ... If you temporally pull your sofa out from the mirror wall about a foot and pile some cushions, pillows, comforters and bed spreads up there you can listen for your self to see if it sounds better... Also stuff some towels laundry baskets of clothes or anything with mass into those corners just for fun... Or large potted plants... As far as my thoughts about putting your system & speakers on the mirror wall was was to get more symmetry, a wall with corners, which usually sounds better as well as having a little more room for you to pull your speakers out wider and into the room a few feet... Having a equilateral triangle between your speakers and your main listening position usually works best... Good luck in your experiments...

 

[Duper]

I thought your Onkyo had EQ... If you temporally pull your sofa out from the mirror wall about a foot and pile some cushions, pillows, comforters and bed spreads up there you can listen for your self to see if it sounds better... Also stuff some towels laundry baskets of clothes or anything with mass into those corners just for fun... Or large potted plants... As far as my thoughts about putting your system & speakers on the mirror wall was was to get more symmetry, a wall with corners, which usually sounds better as well as having a little more room for you to pull your speakers out wider and into the room a few feet... Having a equilateral triangle between your speakers and your main listening position usually works best... Good luck in your experiments...

Maybe higher end Onkyo receivers have the option to do some EQ. Mine only has the AutoEQ option with the factory provided mic. I should post the frequency responses here with and without Auto EQ to see if smart people would see any difference. When I looked at it, it did not had any noticeable difference (but I am new to this and most likely was looking at wrong things). I can certainty pull out the sofa to test out how it would sound. The corners of the room are sort of packed with stuff that not necessarily absorb the sound. I will take the pictures of the room and will upload it here. I see what you meant about swapping TV and sofa around, unfortunately it won't happen, it would be just too much work and the room would not be functional.

 

[Duper]

So I did few more tests yesterday. With the sliding door open (normal listening situation), door closed, and sofa moved about 1ft away from the wall. I also added make shift foam diffuser panel on the mirror wall. In my untrained opinion the graphs look about the same if not worst. What am I missing here? Attaching some pictures of the room as well.

 

[sm52]

It seems that during the measurement, not one speaker is working, but two. After the reference signal.

 

[Duper]

It seems that during the measurement, not one speaker is working, but two. After the reference signal.

No idea how that is possible, only left speaker output was selected. Maybe you are referring to the subwoofer and the Left speaker? Also, my room has a lot of reflections, maybe that was the case?

 

[ddude003]

Yea... Your room has a _lot_ of reflective surfaces... Glass windows and doors, mirror wall, hard wood floor, big coffee table... Diffusion won't help much at this point... And styrofoam won't diffuse much if any... Absorption and lots of it is what your room needs... Bass and wide-band... You could only find 3 sofa pillows??? Any chance you can put a rug down in front of the system... That is going to be a tough room... I guess the real question is: how does it sound to you?

 

[sm52]

First you need to measure the left speaker separately, then the right speaker separately, then the subwoofer separately.

 

[Duper]

Yea... Your room has a _lot_ of reflective surfaces... Glass windows and doors, mirror wall, hard wood floor, big coffee table... Diffusion won't help much at this point... And styrofoam won't diffuse much if any... Absorption and lots of it is what your room needs... Bass and wide-band... You could only find 3 sofa pillows??? Any chance you can put a rug down in front of the system... That is going to be a tough room... I guess the real question is: how does it sound to you?

The rug definitely out of the question, with little kid and animals it would be to hard to keep the room clean.
It does sound good when you do not have anything to compare against. Before I added mini-dsp to EQ the sub, base was way too loud, but now it is fine. Improvement in the speech dialogue is always desired, but that is another subject. At least I know that bot speakers will sound about the same, with speaker B being slightly better.