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5" with a sub vs 8" inch monitors with no sub
Old 1st November 2019
  #1
Gear Head
 

Question 5" with a sub vs 8" inch monitors with no sub

Hi!

Seems like I'm asking the age old question, but mine has a twist. I have a null at around 115hz (phase cancellation) in my room that needs fixing, and I was thinking a sub would be a good option for that. I own a measurement microphone, I've done rigorous testing, my room is treated to an extent (when I start adding more treatment, the response turns into utter crap filled with many nulls), the null seems to be present no matter the "possible" placements of my studio monitors. Now, it is possible to place the sub at more than just "possible" monitor placements, and it being closer to the floor, should deliver a completely different response.

Here comes the question:

Should I just keep my 8" monitors and not experiment with a sub cause it will most definitely not be able to fix the null, OR is there a pretty good chance it will work, and if yes, is there no point in using the 8" monitors anymore since I don't really need their low end abilities anymore, and can switch to their 5 inch versions, no?

Also, maybe I could introduce more treatment into the room which I purchased and is just collecting dust on my attic by having a sub, basically, by being able to "move" the low end around the room without moving my mixing position.

Thanks!
Old 1st November 2019
  #2
What is the frequency response of your 8" monitors? If your room has the null, then I would fix the room, by tuning it better.
Quote:
Also, maybe I could introduce more treatment into the room which I purchased and is just collecting dust on my attic
No maybe, definitely do it
Old 1st November 2019
  #3
Gear Head
 

I did try using all of it, and like I said above, it just made <500hz response a lot worse, introducing all kinds of nulls (somehow) while not making RT60 and the waterfall graphs much better. My monitors, I own Fluid Audio FX8s, go down to 40hz in my 370cm X 320cm X 255cm room according to REW measurements, although they are capable of going to around 35ish hz based on some charts I've seen of them in anechoic chambers.
Old 1st November 2019
  #4
How thick is your treatment?
Old 4 weeks ago
  #5
Lives for gear
 

Quote:
Originally Posted by Mr. Maki View Post
I did try using all of it, and like I said above, it just made <500hz response a lot worse, introducing all kinds of nulls (somehow) while not making RT60 and the waterfall graphs much better. My monitors, I own Fluid Audio FX8s, go down to 40hz in my 370cm X 320cm X 255cm room according to REW measurements, although they are capable of going to around 35ish hz based on some charts I've seen of them in anechoic chambers.
That's interesting ..or perhaps unexpected?
Could it be the placement of the mic in the room changed? (or the speakers)

That could easily account for changes like that.

Here's a good app for visualizing for specific room dimension and it's trouble frequencies what we're up against.
http://www.hunecke.de/en/calculators...igenmodes.html
Old 4 weeks ago
  #6
Lives for gear
Take one of your current 8" monitors and pretend it's a sub. Make some measurements and see if you can position it to avoid the null.

Chris
Old 4 weeks ago
  #7
Gear Head
 

Quote:
Originally Posted by johannburkard View Post
How thick is your treatment?

I have 2 8" rockwool bass traps for first reflection points and 2 20" rockwool superchunks in the 2 frontwall corners. Those 2 things made the biggest difference in the sound of the room, the more I added, the more diminishing returns I got, yes there was a waterfall difference like I said, although not a huge one, but the response got super weird as well which is why I took out the rest of the treatment (aka more 8" bass traps)

Quote:
Originally Posted by Wayne View Post
That's interesting ..or perhaps unexpected?
Could it be the placement of the mic in the room changed? (or the speakers)

That could easily account for changes like that.

Here's a good app for visualizing for specific room dimension and it's trouble frequencies what we're up against.
http://www.hunecke.de/en/calculators...igenmodes.html
Thanks for the suggestion, I already kinda did that, and it clearly shows I have a mode problem at around 115Hz at speaker height. In REW room simulation it "predicts" that if I got a sub with a crossover at around 100hz, and then place it either to the left or right of one of my speakers, it shows the null would disappear with a very neutral response. That's what I really have right now, everything is KINDA flat below 150hz except a nasty 115hz and 80hz phase cancellation null.

Quote:
Originally Posted by chris661 View Post
Take one of your current 8" monitors and pretend it's a sub. Make some measurements and see if you can position it to avoid the null.

Chris
That's what I thought about too, seems like a very solid idea, measure the response of only 1 speaker, move it around the room and repeat.
Old 4 weeks ago
  #9
Quote:
I did try using all of it, and like I said above, it just made <500hz response a lot worse
?? just because you used all your treatment, doesn't mean you tuned your room.

Tuning your room involves measuring sine waves and moving things around and making sure you have enough diffusers, bass traps and acoustic absorption to tune it flat as possible.
Old 4 weeks ago
  #10
Gear Head
 

Quote:
Originally Posted by CJ Mastering View Post
?? just because you used all your treatment, doesn't mean you tuned your room.

Tuning your room involves measuring sine waves and moving things around and making sure you have enough diffusers, bass traps and acoustic absorption to tune it flat as possible.
Tuning?
Like playing a sine wave live and moving stuff around while a measurement mic is active? Got a guide for that? Sounds intriguing
Old 4 weeks ago
  #11
Quote:
Originally Posted by Mr. Maki View Post
Tuning?
Like playing a sine wave live and moving stuff around while a measurement mic is active? Got a guide for that? Sounds intriguing
If it was only that simple. It took me 5 full days to tune both my rooms.

Here is some reading material that will 'guide' you and its by Ethan Winer, a good man!!
https://realtraps.com/art_tuning.htm

Here is something else also:
https://www.acousticfields.com/tuning-a-room/
Old 4 weeks ago
  #12
Here for the gear
 

JBL 305 & sub -vs- JBL 308

I am looking at similar choice between

JBL 305P MkII Monitors +LSR310S Subwoofer ($572)

-vs-

JBL 308P ($550)

Seems to me the sub would handle that low end more efficiently, and would be more clear at louder volume. Anybody have experience with both?

Thanks!

billy
Old 4 weeks ago
  #13
Gear Nut
That price for the LSR310 sub and 305P MkII bundle is about what the LSR310 costs on its own here in Australia, so if I was choosing I'd go for that bundle. It's like buying the sub & getting the monitors free.
Old 4 weeks ago
  #14
Gear Maniac
 

Don't subs usually kick in lower than 115Hz? I'm not sure how that will help your very specific problem. But maybe the REW program is right. Can you borrow a sub (buy with return policy) just to check?

It does seem like the measurement point is specifically at a null point. If you move the measurement mic around a bit (forward, backward) is the null still there? It doesn't seem possible that the exact same frequency would be cancelling everywhere in the room. It could be as simple as moving your setup forward or back a couple feet.

Alternately, try placing only one bass trap at various places in the room and see if you can kill that one null. Don't worry about what it does to other frequencies at first. If you find a spot, you can build a Helmholtz resonator bass trap tuned to just that frequency and place it in that specific place. You could do another for 80 Hz if needed.

Last edited by dirker; 4 weeks ago at 01:03 AM..
Old 4 weeks ago
  #15
Lives for gear
 
grasspike's Avatar
Quote:
Originally Posted by billy33 View Post
I am looking at similar choice between

JBL 305P MkII Monitors +LSR310S Subwoofer ($572)

-vs-

JBL 308P ($550)

Seems to me the sub would handle that low end more efficiently, and would be more clear at louder volume. Anybody have experience with both?

Thanks!

billy
I run the older LSR-305 inch monitors along with the LSR 10" sub

It's a great combination highly recommend.

I much prefer a pair of 5" speakers and a Sub over a pair of 8" monitors with no Sub.

I used to have a pair of 8" monitors didn't like them nearly as much
Old 4 weeks ago
  #16
Lives for gear
Quote:
Originally Posted by billy33 View Post
I am looking at similar choice between

JBL 305P MkII Monitors +LSR310S Subwoofer ($572)

-vs-

JBL 308P ($550)

Seems to me the sub would handle that low end more efficiently, and would be more clear at louder volume. Anybody have experience with both?

Thanks!

billy
It also improves the efficiency of your 5" nearfields, when you add a sub.
Old 4 weeks ago
  #17
Gear Head
 
JayCutler's Avatar
 

I'm an advocate for 3 or 4 way systems because each driver is doing what's it's best at, and you're not asking those drivers to go into territories they're not all that good at. As a result, you're likely to have clearer mid-range, tighter mid-bass and more controlled and extended bottom end (vs a 2 way set up).
Old 4 weeks ago
  #18
Lives for gear
Quote:
Originally Posted by JayCutler View Post
I'm an advocate for 3 or 4 way systems because each driver is doing what's it's best at, and you're not asking those drivers to go into territories they're not all that good at. As a result, you're likely to have clearer mid-range, tighter mid-bass and more controlled and extended bottom end (vs a 2 way set up).
Likewise, but it depends on the crossover tech and efficiency. Crappy crossovers will be counterproductive to that.
Old 4 weeks ago
  #19
Gear Head
 
JayCutler's Avatar
 

Quote:
Originally Posted by VenVile View Post
Likewise, but it depends on the crossover tech and efficiency. Crappy crossovers will be counterproductive to that.
Agreed. I was coming from an assumption of proper implementation, placement, etc.
Old 4 weeks ago
  #20
Lives for gear
 
tymish's Avatar
 

Quote:
Originally Posted by dirker View Post
Don't subs usually kick in lower than 115Hz? I'm not sure how that will help your very specific problem. But maybe the REW program is right. Can you borrow a sub (buy with return policy) just to check?

It does seem like the measurement point is specifically at a null point. If you move the measurement mic around a bit (forward, backward) is the null still there? It doesn't seem possible that the exact same frequency would be cancelling everywhere in the room. It could be as simple as moving your setup forward or back a couple feet.

Alternately, try placing only one bass trap at various places in the room and see if you can kill that one null. Don't worry about what it does to other frequencies at first. If you find a spot, you can build a Helmholtz resonator bass trap tuned to just that frequency and place it in that specific place. You could do another for 80 Hz if needed.
I was thinking that too. I have the 5 in. monitors and sub setup in my room. The sub crosses over at 80 Hz. The issues between 100 - 200 are there regardless of the sub and from what I've been able to gather from measurements have more to do with distances of speakers and listening position between the floor and ceiling and the front wall. These are classic issues with typical home and office height ceilings and smallish rooms. I notice it smooths out when I put the measurement mic at the standing height of mix position. Do measurements and move the mic up and down.


I've taken out the ceiling and filled the joist cavities with 6-9 inches of rockwool and covered with acoustic cloth. It's certainly helped but that 115 Hz null and 150 Hz peak is still around a bit. It takes a lot of treatment to deal with that. When I can I'll be adding some bass traps but it's a trick to determine where they really need to be placed for best effect.
Old 4 weeks ago
  #21
Gear Head
 

I've done what somebody suggested, place one of my 8" monitors on the ground pretending it's a sub. It did fix the huge 115hz null when placed in either of the front corners, but, it only made things worse introducing a new null when placed in the middle. I can't remember where exactly did it introduce a null to be honest, but I'm sure it was in the range below 80hz.

Take note that moving the "pseudo sub" around the corner area made a difference, but not improvements, as in, yes this spectral range is now more flat, but it also introduces a null at another point, so it's a matter of compromise at this point.

To conclude, not bad at all, I am impressed to be honest, I probably will get a sub at some point and maybe downgrade the speakers to a 5" variant if the above discussed crossover and amp implementations are flawless. After that, I'll probably EQ the peaks and small nulls which are again present even after placing the "sub" in the corner.

Red - Default right speaker measurement at it's current height and position
Orange - Placed in the right corner of the room
Purple - Placed in the left corner of the room


Old 4 weeks ago
  #22
Quote:
Originally Posted by tymish View Post
When I can I'll be adding some bass traps but it's a trick to determine where they really need to be placed for best effect.
When I test positions for acoustic treatment, I basically measure-move-measure-repeat. I spend zero time looking at the results, just trying to get as many measurements in as possible. I look at the results after I'm done.

However, if you have measurements already and can see at what frequency your room modes are, you can use this room mode calculator to find zones of high pressure for specific modes.
Old 4 weeks ago
  #23
Lives for gear
 
tymish's Avatar
 

Quote:
Originally Posted by johannburkard View Post
When I test positions for acoustic treatment, I basically measure-move-measure-repeat. I spend zero time looking at the results, just trying to get as many measurements in as possible. I look at the results after I'm done.

However, if you have measurements already and can see at what frequency your room modes are, you can use this room mode calculator to find zones of high pressure for specific modes.
Oh yeah, I've been using AMROC for a while. Fantastic tool. My room isn't a rectangle and has some odd features so there's a point where gets a bit limited. It also doesn't account for SBIR (speaker boundary interference) which is what I think I'm dealing with.
Old 4 weeks ago
  #24
Gear Nut
 

Quote:
Originally Posted by Mr. Maki View Post

Take note that moving the "pseudo sub" around the corner area made a difference, but not improvements, as in, yes this spectral range is now more flat, but it also introduces a null at another point, so it's a matter of compromise at this point.
And now you've discovered why two subs can sometimes be the right choice!

https://www.soundonsound.com/techniq...t-control-room

https://mehlau.net/audio/multisub_geddes/
Old 4 weeks ago
  #25
Lives for gear
 
tymish's Avatar
 

Quote:
Originally Posted by Mr. Maki View Post
I've done what somebody suggested, place one of my 8" monitors on the ground pretending it's a sub. It did fix the huge 115hz null when placed in either of the front corners, but, it only made things worse introducing a new null when placed in the middle. I can't remember where exactly did it introduce a null to be honest, but I'm sure it was in the range below 80hz.

Take note that moving the "pseudo sub" around the corner area made a difference, but not improvements, as in, yes this spectral range is now more flat, but it also introduces a null at another point, so it's a matter of compromise at this point.

To conclude, not bad at all, I am impressed to be honest, I probably will get a sub at some point and maybe downgrade the speakers to a 5" variant if the above discussed crossover and amp implementations are flawless. After that, I'll probably EQ the peaks and small nulls which are again present even after placing the "sub" in the corner.

Red - Default right speaker measurement at it's current height and position
Orange - Placed in the right corner of the room
Purple - Placed in the left corner of the room


What that seems to be telling us is that the 110Hz issue will still be there even with the sub setup. You're not going to want to have a crossover frequency for a sub nearly that high, usually around 80 Hz so any speaker you put there will be affected whether a 5 in. with sub or 8 in. full range..
Old 3 weeks ago
  #26
Gear Head
 

Quote:
Originally Posted by tymish View Post
What that seems to be telling us is that the 110Hz issue will still be there even with the sub setup. You're not going to want to have a crossover frequency for a sub nearly that high, usually around 80 Hz so any speaker you put there will be affected whether a 5 in. with sub or 8 in. full range..
I planned to set the crossover to 120hz, if that doesn't work then 200hz. Is that a terrible idea? I mean in theory I don't mind those frequencies being mono, but I wonder if everything in practice will sound "localized" and "to one side" of the room.
Old 3 weeks ago
  #27
Gear Head
 
JayCutler's Avatar
 

Quote:
Originally Posted by Mr. Maki View Post
I planned to set the crossover to 120hz, if that doesn't work then 200hz. Is that a terrible idea? I mean in theory I don't mind those frequencies being mono, but I wonder if everything in practice will sound "localized" and "to one side" of the room.
In my experience, 80hz is the highest I could go without hearing localization effects, but you may be okay with 120hz. I would probably avoid going as high as 200hz.
Old 3 weeks ago
  #28
Gear Head
 

have you tried a baffold?
Old 3 weeks ago
  #29
Quote:
Originally Posted by Mr. Maki View Post
I planned to set the crossover to 120hz, if that doesn't work then 200hz. Is that a terrible idea?
When I had a sub to try out, I ran it up to 120 Hz or whatever the maximum of Genelec GLM/SAM is. I felt that it was clearly localizable. So much so that I'd rather get two smaller 8" subs than one 10" sub now.
Old 3 weeks ago
  #30
Gear Head
 

Quote:
Originally Posted by johannburkard View Post
When I had a sub to try out, I ran it up to 120 Hz or whatever the maximum of Genelec GLM/SAM is. I felt that it was clearly localizable. So much so that I'd rather get two smaller 8" subs than one 10" sub now.
So you're saying, getting two subs, placing them in each corner and setting their crossover at something as high as 200hz would still make it sound balanced again? It would screw with the stereo image I'm sure though, especially snares which are panned hard left/right.
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