Sub has terrible rolloff in REW

[jcfuller]

Hi all,

Issue:
I have a Monolith M-215 that I recently purchased. I'm having trouble getting a trendline that looks halfway decent in REW with a UMIK-1. I have tried using the THX settings on the sub and also turning THX off and EQ'ing the sub myself. Every thing I've tried produces similar results. My crossover in the AVR is set to 80 Hz with Audyssey on and 80Hz on the sub with Audyssey OFF.

Between 80 and 70 Hz everything appears okay, then starting at 70Hz, the slope drops off dramatically, almost linear to 0dB at 33Hz (See attached REW Graph). I would expect a flat trendline with nulls here and there, but not sloping straight down.

I've tried moving the sub to different locations in the room. I've also taken measurements at other locations in the room. I've disabled Audyssey in the AVR. All with similar results There are no acoustical room treatments at this time. I wanted to see where I needed to add room treatment based on my REW measurements, but this seems way off.

Any ideas are greatly appreciated.

Equipment:
Denon AVR-X4500H
Emotiva XPA-7
Monolith M-215

Configuration: 5.1.4

 

[lovinthehd]

It's just a bass-sucking room? You sure it's not the sub? Have you used other subs with different results? How does it sound? Looks like it's more a matter of level overall but as to the why/what no particular ideas for you....

 

[ryanosaur]

It could be room placement and where your LP/measurement positions are.
Also, it is not unheard of for a U-Mik to not measure properly, though this usually applies up high, I've seen some mention of lower frequency borked-eness.

That Sub is a beast, but nothing can destroy a good subwoofer's performance like room acoustics.

It'll be a total PITA, but have you tried the Sub Crawl to see if there is a better spot in the room for your Sub?
Sometimes the corner is the absolute worst location. It's a shame that this is almost always the first place people think about putting their Sub.

 

[jcfuller]

It could be room placement and where your LP/measurement positions are.
Also, it is not unheard of for a U-Mik to not measure properly, though this usually applies up high, I've seen some mention of lower frequency borked-eness.

That Sub is a beast, but nothing can destroy a good subwoofer's performance like room acoustics.

It'll be a total PITA, but have you tried the Sub Crawl to see if there is a better spot in the room for your Sub?
Sometimes the corner is the absolute worst location. It's a shame that this is almost always the first place people think about putting their Sub.

Thanks for the reply. I did put the sub in the LP and listened around the room, and believe it or not, that was one of the best spots. I have the sub on a furniture dolly so I can wheel it around the room to test different locations.

 

[lovinthehd]

I was just looking at what you had under the sub, thanks

 

[ryanosaur]

Thanks for the reply. I did put the sub in the LP and listened around the room, and believe it or not, that was one of the best spots. I have the sub on a furniture dolly so I can wheel it around the room to test different locations.

There is still a trick in this... Corner loading a Sub makes it Louder... not necessarily cleaner or better. Be careful to not fall for the common trap of believing louder sounds better. Listen carefully to the quality of sound rather than the quantity.
Clearly, something isn't right, though...
What you should be looking for when doing the Sub Crawl is clean bass, and hopefully where it matters.
I would try again, and use some different material. (What did you use when doing it before?) I found music works best for me, but others swear by pink noise and a few replay movie scenes.
For music, you want something that has some range to the bass, and hopefully consistent. I used Gorillaz Laika Come Home which was not consistent, but had good range. It's trite, but Daft Punk Get Lucky is a good cut as it is repetitive and all over the place.
It took me almost an hour the first time I did it, and it was crawling into and out of the corners that helped me start hearing what was really going on!

 

[lovinthehd]

The amount of drop off below xover is so extreme it must be audible, yes? Don't even know how measuring that swing is possible (100dB drop?).

 

[William Lemmerhirt]

Looks like it’s not even active. Is this sweep done in direct mode? Or somehow sub off?
The 215 should be going well bell 20hz so, I suspect configuration.

 

[jcfuller]

Looks like it’s not even active. Is this sweep done in direct mode? Or somehow sub off?
The 215 should be going well bell 20hz so, I suspect configuration.

Exactly my thoughts on it not event appearing active. It looks like only the mains are active. In fact the sub is on and moving, obviously not moving as much as expected.

I'm not sure what direct mode is. I'm a noobie when it comes to REW, just starting using it with this issue since I expected way more low end sound/feel. I read the instructions on setting it up and taking measurement. Attached is the measurement window screenshot. No input right now since I don't have the mic connected.

The AVR settings are: speaker configuration 5.1.4. Sub crossover 80Hz, LFE 120 Hz, Sub Level setting is currently +4dB.

I even tried hooking up my old receiver to it and got the same slope. I connected my old DIY 15" subwoofer and its slope has a similar trend by with less volume.

 

[jcfuller]

There is still a trick in this... Corner loading a Sub makes it Louder... not necessarily cleaner or better. Be careful to not fall for the common trap of believing louder sounds better. Listen carefully to the quality of sound rather than the quantity.
Clearly, something isn't right, though...
What you should be looking for when doing the Sub Crawl is clean bass, and hopefully where it matters.
I would try again, and use some different material. (What did you use when doing it before?) I found music works best for me, but others swear by pink noise and a few replay movie scenes.
For music, you want something that has some range to the bass, and hopefully consistent. I used Gorillaz Laika Come Home which was not consistent, but had good range. It's trite, but Daft Punk Get Lucky is a good cut as it is repetitive and all over the place.
It took me almost an hour the first time I did it, and it was crawling into and out of the corners that helped me start hearing what was really going on!

When doing the bass crawl I used different frequency tracks. 30, 40, 50Hz, and tried to find the best sounding location.

Right now I'd just like to get a trend line that doesn't go straight down. If I could get that, then I could worry about smoothing out the bass frequency.

 

[Pogre]

Looks like it’s not even active. Is this sweep done in direct mode? Or somehow sub off?
The 215 should be going well bell 20hz so, I suspect configuration.

Agreed.

What are your speaker settings? Large/small? Crossover setting? LFE or LFE + Mains? It doesn't look like your sub is even operating. Are the drivers moving when you do sweeps?

 

[Pogre]

Exactly my thoughts on it not event appearing active. It looks like only the mains are active. In fact the sub is on and moving, obviously not moving as much as expected.

I'm not sure what direct mode is. I'm a noobie when it comes to REW, just starting using it with this issue since I expected way more low end sound/feel. I read the instructions on setting it up and taking measurement. Attached is the measurement window screenshot. No input right now since I don't have the mic connected.

The AVR settings are: speaker configuration 5.1.4. Sub crossover 80Hz, LFE 120 Hz, Sub Level setting is currently +4dB.

I even tried hooking up my old receiver to it and got the same slope. I connected my old DIY 15" subwoofer and its slope has a similar trend by with less volume.

Direct mode is a setting in your receiver. Have you run Audyssey MultEQ? Again, check your speaker settings. They should be set to SMALL and we usually recommend 80 hz as a starting point for crossing over. If your speakers are set to LARGE it will bypass your sub altogether.

A M215 in that little room... you ain't messing around! Ha ha!

 

[William Lemmerhirt]

Ok. So the sub moves with normal content. If I understood correctly.
When you run a sweep, can you hear/feel the sub? If yes, then it could be a setup thing, or some anomaly in rew. I’ve never seen a sweep like that, and still found the sub to be outputting sound during a sweep.
And yes, as @Pogre mentioned, direct is a sound mode in the AVR. In most cases, it disables the subwoofer. So for music, or anything without an actual .1(LFE) channel prerecorded it will disable the sub. This would include REW sweeps since there’s no LFE. It’s just redirected bass from below the XO, just like music.
For movies that DO have a .1 channel, it will activate the sub, but won’t use any processing/audyssey.

So if the AVR is set to “Direct” when running sweeps, the sub will not have output. Not all inputs are set to the same sound mode , so for example. BD/DVD could be set to DSU(Dolby surround) and the CD, or aux input(assuming that’s what your using for the PC connection)could be set to stereo(uses sub) or direct(no sub). All you have to do is scroll through the sound modes to find what you want. I usually sweep in “stereo” for subwoofer integration. Some will sweep in a surround mode, using only the CC to avoid comb filtering with the mains. Or simply use one, then the other main. That’s later though lol.

 

[Mark E. Long]

Direct mode is a setting in your receiver. Have you run Audyssey MultEQ? Again, check your speaker settings. They should be set to SMALL and we usually recommend 80 hz as a starting point for crossing over. If your speakers are set to LARGE it will bypass your sub altogether.

A M215 in that little room... you ain't messing around! Ha ha!

That’s the biggest sub I’ve ever seen!! That’s definitely impressive looking .

 

[lovinthehd]

Back to a question that I still don't see answered.....what does it sound like? It should be completely devoid of lower bass from the measurement. Or is there somewhat normal sounding bass? You say the cones don't move as much as you expect, which sounds right (would take a lot to get significant visible cone movement).

 

[Mark E. Long]

Back to a question that I still don't see answered.....what does it sound like? It should be completely devoid of lower bass from the measurement. Or is there somewhat normal sounding bass? You say the cones don't move as much as you expect, which sounds right (would take a lot to get significant visible cone movement).

That big boy ought to pressurize that room I’d think from the looks of his readings it looks like he doesn’t have something set right in his avr or the sub itself .

 

[jcfuller]

Hi guys, wanted to post an update. I installed REW on a different laptop and now my measurements are looking more normal (See attached). I wonder if there is a problem with the laptop sound card or configuration.

I think I'm on the right road now.

Thanks everyone for your advice and feedback.

Back to a question that I still don't see answered.....what does it sound like? It should be completely devoid of lower bass from the measurement. Or is there somewhat normal sounding bass? You say the cones don't move as much as you expect, which sounds right (would take a lot to get significant visible cone movement).

Wanted to answer you question. It was devoid of bass when using the signal generator and measure action on the laptop using REW. When I played low frequency sound clips from YouTube, it would do OK. That is what lead me to trying a different laptop after unsuccessfully tweaking the sound card settings on the first laptop I tried. Thanks for the help!

 

[Pogre]

That looks WAY better! Now you're on the right track.

 

[William Lemmerhirt]

That’s more like it!!!
Nice work.

 

[Pogre]

Are your speakers Focal? Just curious, they look like Focal. I've been admiring some of their speakers from afar. They make some beautiful looking speakers.