The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
JBL Cabinet Resonance, Anyone? Studio Monitors
Old 6th March 2014
  #1
Here for the gear
 

JBL Cabinet Resonance, Anyone?

Has anyone experienced any cabinet resonance from the LSR305s?

I recently bought a pair of these amazing monitors. I was very happy with them until.. I was playing a VST Synth through them (sine waves) and noticed an annoying resonance coming from the left monitor when I played the A note on my midi keyboard (220hz or A3). As I turned up the volume a little on my audio interface, I began to hear it in the right monitor as well. So I decided to see if anyone else had this problem, and found this video on YouTube: Resonant Cabinet (in G note - Bass) JBL LSR-305 (monitor on right) - YouTube This guy had the same resonance problem I had, but at the G note instead of the A note. So I exchanged my LSR305s for a new pair, but I still hear some resonance from the left monitor at the A note, and it's more pronounced at the B note (247hz). The weird thing is that everything sounds amazing on these monitors except for the sine wave at 247hz. I was wondering if anyone else had experienced this same problem.

Best Regards,
-Ed
Old 6th March 2014
  #2
Lives for gear
What are the dimensions of your room?

Sounds like a resonance/standing wave caused by your room
Old 6th March 2014
  #3
Here for the gear
 

My room dimensions are 11 ft by 11 1/2 ft. by 7 1/2 ft.

Quote:
Originally Posted by tenderboy View Post
What are the dimensions of your room?

Sounds like a resonance/standing wave caused by your room
Old 6th March 2014
  #4
Registered User
First thing to do is swap them around - if it's still the Left one (as in, if the problem moves to the other physical speaker) then it isn't a problem with the speaker, but a problem with that particular location int he room. Speaker boxes of just about any quality and construction can have resonance problems - that's the nature of pumping air with lots of watts. It used to alarm me when I spent serious money on speakers to hear resonance problems, so sometimes you just have to accept what you can't change.

I've read about a famous engineer who have build monitor speakers out of marble slabs - that's pretty much what you would need to do to banish resonances forever.
Old 6th March 2014
  #5
Here for the gear
 

I swapped them around and the same speaker still resonates. I also tried playing the speakers in different sized rooms, but the resonance doesn't go away.

Quote:
Originally Posted by Kiwi View Post
First thing to do is swap them around - if it's still the Left one (as in, if the problem moves to the other physical speaker) then it isn't a problem with the speaker, but a problem with that particular location int he room. Speaker boxes of just about any quality and construction can have resonance problems - that's the nature of pumping air with lots of watts. It used to alarm me when I spent serious money on speakers to hear resonance problems, so sometimes you just have to accept what you can't change.

I've read about a famous engineer who have build monitor speakers out of marble slabs - that's pretty much what you would need to do to banish resonances forever.
Old 7th March 2014
  #6
Here for the gear
 

Can anyone that has the LSR305s let me know if they also have the same resonance problem?
Old 7th March 2014
  #7
Registered User
I think if you play sine waves into any monitor speaker you will find it's resonant frequencies and drive yourself nuts. All speakers are compromised somehow - it's the laws of physics. How do they sound with a well mastered audio file? If you are listening to a sine wave in isolation you are probably playing it too loud, relatively speaking.
Old 7th March 2014
  #8
Here for the gear
 

With a well mastered audio file they don't have any problems.

Quote:
Originally Posted by Kiwi View Post
I think if you play sine waves into any monitor speaker you will find it's resonant frequencies and drive yourself nuts. All speakers are compromised somehow - it's the laws of physics. How do they sound with a well mastered audio file? If you are listening to a sine wave in isolation you are probably playing it too loud, relatively speaking.
Old 7th March 2014
  #9
Gear Guru
 
drBill's Avatar
Learn the beauty and "secret" of HPF's. After that, start down the never-ending journey of the perfect mix room.
Old 7th March 2014
  #10
Lives for gear
 

subscribing.. No time but to say as apposed to 'in a mix' mastered or not, this could rear it's head within the processes in mixing. As in any bass track for example.
Very interesting if JBL let this happen.
Old 7th March 2014
  #11
Lives for gear
 

I think its more to do with the control room and the gain structure than the speakers itself.

It sounds like the room needs to be less cube. break up the 90 degree angles. take a small mirror go flat against the side walls, move from back to the front (where the speakers at) when you see the speakers in the mirror, go ceiling to floor with a blanket stapled.

master fader at 0db, use a monitor controller or some other volume device for attenuation.
an spl meter is nice too so you can hear what goes on at 85,90,95, and 100 db. remember this: the louder it is, the more the room will color the sound, and make the mix lie. especially in a not so ideal mixing room.
Old 7th March 2014
  #12
Registered User
The fact that one speaker does it and the other, supposedly identical speaker, means there is a difference in construction between them. However - all affordable speakers are compromised, and even the less affordable ones are still compromised. Choice and quality of material and construction are all decided by accountants, not by the ultimate desirable technical solutions. If you made speaker cabinets out of something very dense and heavy they would perform wonderfully, but they would be super expensive and the freight would be excessive, and people would complain about the weight. So you are going to get lightweight cabs made from plywood or MDF, and they are going to rattle. Sorry, it happens.

Any monitor speaker is a less-than-perfect window giving you a view of the sonic landscape you are creating. Any monitor and room combination is going to be different, so stop thinking that somehow you are going to get yourself the perfecting monitoring enviroment: it does not matter. What matters is that you create a mix that will sound good on any number of wildly different speakers that will be used by your target market. So get several different monitoring options - all with flaws in them - and learn each one and focus on the music you are creating, not on any one particular set of monitors.

It's like windows or optical glasses - everything is flawed, but you can learn to look "through" them, not "at" them. Same with audio monitors - you need to listen "through" them, not "to" them.
Old 7th March 2014
  #13
Lives for gear
Quote:
Originally Posted by Kiwi View Post
The fact that one speaker does it and the other, supposedly identical speaker, means there is a difference in construction between them. However - all affordable speakers are compromised, and even the less affordable ones are still compromised.
+1

If you ever try building them, and then trying to get rid of all resonances you realize it takes a hell of an effort to make speakers that don't have any of these things. My current subs are over 200lbs each and I image could be even a tad cleaner (and insanely expensive) if they were made out of the same thickness of phenolic resin. But eventually the cost to even DIY becomes an issue ...wilson audio is an example what it costs to build speakers from eg phenolic. And even they are not without their sacrifices.

Speaker building/design is an ultimate lesson in the quid pro quo nature of physics.
Old 20th March 2014
  #14
I have the exact same resonance in my lsr 305 speaker (at 225hz). I found it using a weird conga loop in logic pro. When mixing at normal volume, everything sounds great though. Except that particular loop, wich has an incredible amount of energy at around 230hz. Funny thing is that if I place my monitor horizontally, the resonance dissapears... Guess we´ll just have to learn to live with it
Old 20th March 2014
  #15
Here for the gear
 

Now I know I'm not the only one experiencing this problem...

Quote:
Originally Posted by Guillermo Berta View Post
I have the exact same resonance in my lsr 305 speaker (at 225hz). I found it using a weird conga loop in logic pro. When mixing at normal volume, everything sounds great though. Except that particular loop, wich has an incredible amount of energy at around 230hz. Funny thing is that if I place my monitor horizontally, the resonance dissapears... Guess we´ll just have to learn to live with it
Old 21st March 2014
  #16
Lives for gear
 
lame pseudonym's Avatar
 

There's a free program called Boxnotes that takes the internal dimensions of your cabinet and gives you all the resonances -- wall to wall and speaker to wall.

It's pretty useful. I recently bought a relatively top-shelf pair of speakers and the cabinet dimensions were pretty close to 1:1:2. Needless to say, the music found the frequency and howled like nuts there.

Boxnotes - Free Speaker Design Software
Old 21st March 2014
  #17
Lives for gear
 

First tighten up anything you can with the speaker. If it continues see about getting a replacement for that one speaker. There are damping products that can be applied to the inside of the cab but why go through that if you have a defective product. For all you know the damping wasn't applied right inside the speaker giving you trouble.

All material will vibrate and resonate at specific frequencies with enough energy. The trick in design is to minimize and damp that natural occurance.
Old 22nd March 2014
  #18
A little warning about opening up the LSR 305's:

After noticing a resonance on one of my speakers i decided to tighten up all the screws, it did help minimize the resonance but it came back after a while.
If i pressed on the back plate with my finger the resonance stopped so i decided to remove the screws and the back plate to see if i could spot anything loose on the inside.
I didn't see anything unusual so after putting the plate back the monitor refused to turn back on.
I didn't force anything inside the speaker and was very cautious so maybe the best is to send it back for fixing/replacement instead of opening the unit.
Fortunately the shop replaced the unit with no questions asked, now all is fine.
Old 1st May 2015
  #19
Hi: the same happened to me 2 days ago, a resonance around 200 Hz on the LF ring, so I guess it looks like a kind of common issue because I have found several people talking about it.

The speaker is still a great performer, maybe some of them just failed...



BTW, this has nothing to do with the room at all.

Last edited by felipousis; 1st May 2015 at 03:31 PM..
Old 3rd May 2015
  #20
Hi: I fixed!

The resonance was related to the ring in the LF driver, so I removed the screws and added Teflon thread seal tape to them, and screw it again, resonance is gone.

Hope this help!
Old 15th November 2016
  #21
Lives for gear
 
dirtROBOT's Avatar
Quote:
Originally Posted by felipousis View Post
Hi: I fixed!

The resonance was related to the ring in the LF driver, so I removed the screws and added Teflon thread seal tape to them, and screw it again, resonance is gone.

Hope this help!
hey sorry to necro - were you referring to the actual front ring around the woofer?
Old 23rd November 2016
  #22
Here for the gear
 

I have a new pair of LSR305 speakers and experience this exact same problem. There are certain low frequencies that when playing my keyboard through the monitors result in a buzz or rattle. I've swapped the speakers (moving left to to right, and right to left) and the sound still happens. So, has nothing to do with the room. Seems to be a design or build quality flaw. I will try the teflon tape suggestion and report back.
Old 23rd November 2016
  #23
Here for the gear
 

I seemed to have resolved the issue. What I did was loosen (not tighten) some of the larger perimeter screws on the back of the speaker. I systematically loosened screws until the buzz caused by low A and G notes/frequencies was gone.
Old 7th December 2016
  #24
Quote:
Originally Posted by dirtROBOT View Post
hey sorry to necro - were you referring to the actual front ring around the woofer?

Yes sir, in my case one screw was the one resonating with the ring with some frequencies, the moment I made the screw wider with the Teflon tape, the problem was gone, in fact, gone forever.
Old 14th December 2016
  #25
Lives for gear
 
dirtROBOT's Avatar
Quote:
Originally Posted by felipousis View Post
Yes sir, in my case one screw was the one resonating with the ring with some frequencies, the moment I made the screw wider with the Teflon tape, the problem was gone, in fact, gone forever.
thanks! going to try that
Old 14th December 2016
  #26
Lives for gear
 
Poinzy's Avatar
 

I've never had resonance issues with my LSR305's. I once owned a set of monitors that did have resonance issues, but those were remedied by tightening the nuts on the bass driver mounting rings. I've never had to make any adjustments on the JBL's.
Old 15th December 2016
  #27
Gear Addict
 

I have a honking resonance on my JBL308's around 150 - 200 range. The back plates on these are a relatively thin metal, and the amp modules preclude just simply applying a stiffening laminate of some sort. There was an article about someone taking one completely apart and filling the front plastic molded cavity spaces with I think spray foam of some sort. They do sound good and my initial reaction to build method was that they were pretty smart incorporating resonant panels into the acoustic modes to stay pretty flat. After hearing mine start honking - I sort of changed that thinking I'll take some advice here and look into checking the component fasteners - definately the easiest first step. I noticed mine when playing synths. In general lower to moderate level playback I didn't notice anything - and I was very impressed by the waveguide dispersion - they're great for general playback ,which is what I bought them for.
Old 15th December 2016
  #28
Gear Addict
 

Great you tube of the issue there.
Old 15th December 2016
  #29
All wooden speaker boxes resonate. Tap on them to hear it. If you hear anything other than what you would hear tapping on concrete, that's resonance.

There are fixes for that. DeFlex panels are one source. Those are latex panels that are glued to the inside walls. One molecule short of a liquid state, these damp any resonances internally and tighten up the low end. Standard box wool will not do that.
Old 2nd January 2017
  #30
Gear Addict
 

To follow up on my comment about the honking cabinet resonance : I found that my issue was the table my monitor was resting on was resonating and vibrating the leg. My bad - and I wanted to clear the air about the cabinet issue. I took the woofer and plastic surround wave guide out on a couple of occasions trying to find if the wave guide was rattling. I did a couple of non-destructive fixes when I discovered the table issue. Fixed that and all is well. JBL in good graces.
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump
Forum Jump