REW Newbie with Salon2

[Luvchampagne]

Hi
I'm dipping my toes into REW and measurements.
Setup: - Mcintosh MacAir -> RME ADI2 DAC FS -> Krell HTS7.1-> Mcintosh MC7270 -> Salon2
Microphone UMIK1

Mcintosh just got rebuilt. New capacitors, resistors, bias checked. Bench tested at 0.005 THD, 98db S/N.

I have quite a challenging room that is open to the dining room/kitchen/hallway
27' x 22' x 18'

Measured at 6 feet. Could someone please help me understand what this graph is saying?

Greatly appreciated.
Thank you

 

[levimax]

That does not look right even for a challenging room. I would try taking a MMM RTA measurement at the listening position.

and see if that makes more sense.

 

[Luvchampagne]

Hi
I'm dipping my toes into REW and measurements.
Setup: - Mcintosh MacAir -> RME ADI2 DAC FS -> Krell HTS7.1-> Mcintosh MC7270 -> Salon2
Microphone UMIK1

Mcintosh just got rebuilt. New capacitors, resistors, bias checked. Bench tested at 0.005 THD, 98db S/N.

I have quite a challenging room that is open to the dining room/kitchen/hallway
27' x 22' x 18'

Measured at 6 feet. Could someone please help me understand what this graph is saying?
1/6 graph adjustment

I've attached Stereophile graphs anechoic and listening room for a baseline.

Greatly appreciated.
Thank you

 

[GXAlan]

Something is weird with your bass rolling off so quickly. It’s as if there is a broken woofer (maybe the rear jumpers aren’t configured properly?)

 

[Keith_W]

I copied the anechoic measurement from Stereophile then used an image editing program to paste it as a transparency on top of your REW measurement. I edited the vertical scale of the Stereophile measurement so that it is comparable. The Stereophile measurements are a little different to the Klippel measurement of the Salon2.

Strictly speaking, the measurements are different. The Stereophile is a measurement of the Listening Window, your measurement is only on-axis. At least I assume it's on-axis. Regardless, it looks as if you are missing a tonne of bass below 180Hz.

Please read this and make sure you are taking measurements correctly.

 

[alex-z]

First off, don't measure the LR combined. You can get phase cancellation which will throw off the results, likely what is happening at 3000Hz. The dip at 1000Hz is inherent to the speakers, and the rolloff above 10000Hz is likely due to microphone angle or location.

Something is wrong in your signal chain because these speakers should not be rolling off sharply below 200Hz. Even in a bad room you would still get bass output, just with peaks and dips caused by the room modes. I recommend connecting your source directly to the amplifier, bypassing the Krell HTS7.1 for now.

I would also strongly recommend measuring at a higher SPL, at least 85dB. You are not getting accurate measurements of the decay rate because of the noise floor, particularly below 600Hz.

For each channel take measurements at your most common listening locations. This is valuable data because you can see how the bass changes, in 99.9% of rooms you will find dedicated subwoofers improve the seat to seat variation.

 

[Luvchampagne]

First off, don't measure the LR combined. You can get phase cancellation which will throw off the results, likely what is happening at 3000Hz. The dip at 1000Hz is inherent to the speakers, and the rolloff above 10000Hz is likely due to microphone angle or location.

Something is wrong in your signal chain because these speakers should not be rolling off sharply below 200Hz. Even in a bad room you would still get bass output, just with peaks and dips caused by the room modes. I recommend connecting your source directly to the amplifier, bypassing the Krell HTS7.1 for now.

I would also strongly recommend measuring at a higher SPL, at least 85dB. You are not getting accurate measurements of the decay rate because of the noise floor, particularly below 600Hz.

For each channel take measurements at your most common listening locations. This is valuable data because you can see how the bass changes, in 99.9% of rooms you will find dedicated subwoofers improve the seat to seat variation.

Thank you for your post.
I will need to wait until tomorrow AM to measure. Noise floor is way too high - 60db+ - in the middle of a windstorm.
Couple Qs.
Don't measure LR combined - should I just select L or R?

Should I disconnect the Krell and use the gain knobs on the Mcintosh to control the input from the RME DAC?

Dumb question but does using a USB cable that is 20 feet long affect the measurements?

 

[staticV3]

The Stereophile is a measurement of the Listening Window, your measurement is only on-axis.

OP's measurements are most certainly in-room, making Revel's own EIR/PIR measurements the most comparable:

Easily compare loudspeakers measurements

www.spinorama.org

Though the result hardly changes: bass and treble are weirdly absent.

 

[Luvchampagne]

One more try for tonight. Looks like my gain setting was not correct. Swapped in my Yamaha MXD1 to see what it would do

 

[alex-z]

Thank you for your post.
I will need to wait until tomorrow AM to measure. Noise floor is way too high - 60db+ - in the middle of a windstorm.
Couple Qs.
Don't measure LR combined - should I just select L or R?

Should I disconnect the Krell and use the gain knobs on the Mcintosh to control the input from the RME DAC?

Dumb question but does using a USB cable that is 20 feet long affect the measurements?

Yes, measure the L and R individually by selecting them in REW.

Yes, RME ADI-2 directly into the MC7270. The ADI-2 has a relatively high peak output voltage, so set the input level switch on the MC7270 to 2.5 volts and gradually increase the volume on the ADI-2 so you don't cause clipping.

No, USB is a digital connection. The signal either makes it through properly or not at all, there is no quality difference like you would get with an analogue signal.

Your most recent measurement looks more like what I would expect from the Salon 2. Bass output down to 30Hz, smaller dips at 1000 and 3000Hz, no high frequency comb filtering. Looks like some dips at 50, 125, and 180Hz due to room modes which is expected.

 

[Luvchampagne]

Thank you. Greatly appreciated. Will do as stated in the AM when I hope the windstorm dies down and my Amazon delivery of USB extension cables comes in.

 

[Luvchampagne]

Was able to find some problems in my system chain while hooking up the mic.
Took measurements with the RME alone and then again with the Krell. The overlays are identical so I'm just posting the Krell+RME.
There's a trough at 44hz and then a spike at 35hz and then the drop from 30hz down which is to be expected.
Lots of room modes. I tried experimenting with the RME and didn't get that far. Lots of tradeoffs.

 

[just1n]

You’ll need to change the scale of that window. -250db to 150db isn’t going to show you anything useful. I think almost every speaker in the world would look straight as an arrow like this. Try 45db to 95db

 

[kemmler3D]

One more try for tonight. Looks like my gain setting was not correct. Swapped in my Yamaha MXD1 to see what it would do

As @alex-z said, this graph looks pretty normal.

My next step (in your shoes) would be to:

1) Download and configure SoundSource for Mac ($40)

2) Use REW to create a set of EQ filters to correct the bass (lots of tutorials on this, it's mostly automatic)

3) Load those into the headphone EQ slot in Soundsource (I know it's not headphones but it works anyway)

4) Enjoy your dramatically smoother bass.

BTW - when you do the graphs, it's important to select the right scale so you can tell what's going on. Normally it's a 50dB scale, in the most recent set it's zoomed out to show 400dB which is more than enough to show the full waveform of a nuclear bomb going off 8 feet from the mic... it tends to make your speaker / room issues look small in comparison.

 

[Luvchampagne]

You’ll need to change the scale of that window. -250db to 150db isn’t going to show you anything useful. I think almost every speaker in the world would look straight as an arrow like this. Try 45db to 95db

Thx. Figured out to do that.

 

[concorde1]

I had similar nightmarish bass rolloff with my setup for many months. I had thought my speakers were faulty.

After much confusion, it turned out:
(a) my DAC at the time had the two channels out of phase with each other -> try phase flipping one channel (it's an option in REW measurement window)
(b) my DAC at the time also was faulty - with strange frequency response anomalies - even my onboard motherboard audio was better.

Also it's worth noting I have or have had other equipment (amps or DAC's) which flip the phase of one channel.

If I ever buy a new device I always will check the phase in REW before making any judgments.

Hope this could help.

 

[Luvchampagne]

I had similar nightmarish bass rolloff with my setup for many months. I had thought my speakers were faulty.

After much confusion, it turned out:
(a) my DAC at the time had the two channels out of phase with each other -> try phase flipping one channel (it's an option in REW measurement window)
(b) my DAC at the time also was faulty - with strange frequency response anomalies - even my onboard motherboard audio was better.

Also it's worth noting I have or have had other equipment (amps or DAC's) which flip the phase of one channel.

If I ever buy a new device I always will check the phase in REW before making any judgments.

Hope this could help.

Are you referring to the top photo? If so, my setup was faulty. One of my RCA jacks was not plugged all the way in. If you're referring to the most recent photos, could you please explain the "nightmarish" bass rolloff comment? Not sure what you're referring to.
Thx

 

[concorde1]

Are you referring to the top photo?

Yes.

Well it's great you resolved it - I didn't realise - I just found this thread now!

 

[boxerfan88]

Glad you found your gain problem, and fixed it.

View attachment 437549

The above chart looks normal for an in-room measurement. The in-room response look pretty good.
(May I suggest using VAR smoothing, makes it easier to see the bass issue.)
I guess you can now move on to the next step of smoothing the bass response with PEQ.
.

 

[alex-z]

There's a trough at 44hz and then a spike at 35hz and then the drop from 30hz down which is to be expected.
Lots of room modes. I tried experimenting with the RME and didn't get that far. Lots of tradeoffs.

Had a look through your latest .mdat file. I would start by using EQ to reduce the peaks around 350, 640, 1300Hz, and 6000Hz. Those problems occur above the Schroeder frequency of your room so fixing them should improve overall tonality and stored energy without harming off-axis response.

For example:

https://prnt.sc/nMz7lZP_U9Wf - right channel EQ

https://prnt.sc/ZlaoKGaI_voo - left channel EQ

The bass is tricky because any corrections will only be useful for a narrow listening window. Before using EQ below 300Hz I would add 1-2 good quality subwoofers. This will fix the bass deficit below 80Hz and reduce the peaks and dips caused by room modes.

Low-pass the subs at 80Hz, high-pass the speakers at 80Hz. I assume your Krell processor supports this, if not you can add that functionality with an external DSP such as a miniDSP Flex.

As for the room acoustics, your decay times and clarity values (ratios of direct vs reflected sound) reach their highest point in the mid-bass region, and gradually worsen at higher frequencies. The bad news is you are losing a significant amount of vocal and instrument detail. The good news is that simple/cheap 2-4" absorption should correct this problem nicely, most residential rooms have the opposite problem and need much thicker absorption.