What do I need to measure speaker cab resonances?

Jump to Latest
#21
tmuikku said:
What I'm trying to say is that its more complicated than that 😀 You can start from there but as you develop the speaker further you might notice things need to change and now your box might need more or less bracing, or no box at all! so, this is as good starting point as any, use some bracing and adjust when needed.

Look for username augerpro, he has done quite extensive testing recently about these, damping and all.
Click to expand...

ha!

well the ‘ adjusting’ part is the one I am asking about.

yeah speaker building can get as complicated as the space shuttle. No doubt.

but practical solutions my man. Practical.

did you see those braces I showed in my attachments?

ok, so I add them. They are hardly any mass so they won’t change the cabinet volume. Wonderful.
ok , the plan is to add two.
my speakers are MTM. 35” long box. Not large at all.
i plan on putting two braces on the sides of each speaker.

ok , then I power the suckers up and listen…………..now what? Lol
what do I adjust and how do I know.

thats the question.


when I dove into doing treatments for my room. Yes it took a long while of trial and error. I put treatments on certain walls. Measured , then tried again.
eventually I started to see a pattern in my room. On what helped. What made certain changes and what didn’t. It took awhile but I finally , after two years pretty much dialed it in.

i guess this is the same
 
#22
stv said:
tmuikku is just trying to give you some background.
don't be mad at him.

because the effects of panel resonance are usually rather small compared to many other factors (ok - I know, that's a dangerous statement).
and it's a rather complicated issue.

you will find plenty of accelerometers (or contact microphones), just use google.
Click to expand...

i am not in the least mad at anyone.
pardon. You don’t know my personally and of course I don’t know yours.
its all good.

i just want to find a way to brace and then to measure what the bracing is doing ( as with my room treatments) and then adjust.

pardon if that came off as I was angry.
i am not at all.

thanks
 
#24
tone? said:
ha!

well the ‘ adjusting’ part is the one I am asking about.

yeah speaker building can get as complicated as the space shuttle. No doubt.

but practical solutions my man. Practical.

did you see those braces I showed in my attachments?

ok, so I add them. They are hardly any mass so they won’t change the cabinet volume. Wonderful.
ok , the plan is to add two.
my speakers are MTM. 35” long box. Not large at all.
i plan on putting two braces on the sides of each speaker.

ok , then I power the suckers up and listen…………..now what? Lol
what do I adjust and how do I know.

thats the question.


when I dove into doing treatments for my room. Yes it took a long while of trial and error. I put treatments on certain walls. Measured , then tried again.
eventually I started to see a pattern in my room. On what helped. What made certain changes and what didn’t. It took awhile but I finally , after two years pretty much dialed it in.

i guess this is the same
Click to expand...

Aa yeah there was some suggestions already how to evaluate difference, I guess you are set. The eventual judgement is your ears and if there is no noticeable change then its a moot point. I suggest you to figure out what you actually need to be doing with the braces to actually make noticeable change thats worth it. Hence good background for it all is necessary 😉 With the products on first post you could tune the wall resonances but they are only gonna get higher up in frequency. Can you push them outside woofers pass band is the question? If not then damping would yield potentially more audible results I speculate. Perhaps the accelerometer or piezo mic or something is fine enough tool to find where the resonance is currently and how much, then see what happens to it when you add a brace and try figure out if it made audible difference.

If its just single brace, put it mid of panel way to push resonances octave up or off center to spread them out, tension the brace some to perhaps push them even higher up. If at all possible stiffen the joints (box corners) and with the bracing make higher aspect ratio panels than it was before to get the resonances up even more. Dampen to reduce the resonances.
 
Last edited:
  • Like
Reactions: tone?
#25
tmuikku said:
Aa yeah there was some suggestions already how to evaluate difference, I guess you are set. The eventual judgement is your ears and if there is no noticeable change then its a moot point. I suggest you to figure out what you actually need to be doing with the braces to actually make noticeable change thats worth it. Hence good background for it all is necessary 😉
Click to expand...

thanks man !

would the braces placed properly and doing a good job affect the freq response positively ?
im assuming that would be a yes.
if it is getting rid of ringing then that should make for a smoother response , or smoother RT60 decay or waterfall.
is my assumption correct?

much appreciated
 
#26
I guess so, what ever it takes to visualize them and evaluate how to reduce them. If there is ringing could be also due to standing wave inside the box, a mode. Any of these would affect frequency response, at least to some direction. In a room one is listening a soup, speaker radiating to all direction and stuff coming to ear from multiple directions and time. It might be hard to discriminate what is what and hearing improvement might be tough. It would be great to see the improvements in the measurements but as already pointed out it might be hard to figure out how to actually make it better.

Actually, I don't have anything to present to you to say for example if box resonances are more or less problematic than standing waves inside the box. What I'd do is try and minimize both with system design and thats it. Improving ready made speaker its just gonna be experimenting with it, try simple brace and evaluate if it was worth it. Perhaps try more complicated scheme if you feel like it. At least its fun to do stuff like this, and a possibility to learn 🙂 It might turn out that all you do is shift issues around but not deal with them. Perhaps damping would help better or getting rid of the box altogether.

edit.
Here is augerpro thread mentioned earlier https://www.diyaudio.com/community/...n-methods-shootout-thread.356130/post-6768728 if you wish to evaluate what the difference might be with or without a brace for example. To me it looks like bracing just shifts the stuff around and it takes damping to actually reduce the resonances. For the box size augerpro is using the resonances happen at midrange like every other issue related to loudspeakers from cone breakup to floor bounce 🙂 What is audible and what is not is again the question that is not directly answered by the graphs. If one wants very good audio quality then of course it pays off to reduce any and all "issues" while not creating worse.
 
Last edited:
  • Like
Reactions: tone?
#27
tmuikku said:
I guess so, what ever it takes to visualize them and evaluate how to reduce them. If there is ringing could be also due to standing wave inside the box, a mode. Any of these would affect frequency response, at least to some direction. In a room one is listening a soup, speaker radiating to all direction and stuff coming to ear from multiple directions and time. It might be hard to discriminate what is what and hearing improvement might be tough. It would be great to see the improvements in the measurements but as already pointed out it might be hard to figure out how to actually make it better.

Actually, I don't have anything to present to you to say for example if box resonances are more or less problematic than standing waves inside the box. What I'd do is try and minimize both with system design and thats it. Improving ready made speaker its just gonna be experimenting with it, try simple brace and evaluate if it was worth it. Perhaps try more complicated scheme if you feel like it. At least its fun to do stuff like this, and a possibility to learn 🙂 It might turn out that all you do is shift issues around but not deal with them. Perhaps damping would help better or getting rid of the box altogether.

edit.
Here is augerpro thread mentioned earlier https://www.diyaudio.com/community/...n-methods-shootout-thread.356130/post-6768728 if you wish to evaluate what the difference might be with or without a brace for example. To me it looks like bracing just shifts the stuff around and it takes damping to actually reduce the resonances. For the box size augerpro is using the resonances happen at midrange like every other issue related to loudspeakers from cone breakup to floor bounce 🙂 What is audible and what is not is again the question that is not directly answered by the graphs. If one wants very good audio quality then of course it pays off to reduce any and all "issues" while not creating worse.
Click to expand...

thanks so much man

it was a pleasure having you chime in. Honestly.

yeah I have read about bracing and how there are different schools of thought , that the bracing just shifts the resonances upwards.

i will carry out the experiments and if you would like to report back.

thanks again for chiming in. i appreciate the knowledge and opinion you brought for me to ponder upon.
 
#28
Of course please post results and observations. Thats most I do, think upon observations and then write about them as it makes better learning process than just reading. And I would be happy to learn more, like you and all of us I think 🙂 Have fun with it!

ps. check the augerpro thread, there might be thing or two about measuring the stuff.
 
  • Like
Reactions: tone?
#29
tmuikku said:
Of course please post results and observations. Thats most I do, think upon observations and then write about them as it makes better learning process than just reading. And I would be happy to learn more, like you and all of us I think 🙂 Have fun with it!

ps. check the augerpro thread, there might be thing or two about measuring the stuff.
Click to expand...

yeah I will definitely read it.
got plenty of time to.
lol

i will post my findings for sure.
i wish I could give more scientific results. But I’ll deal with that when the time comes.
again thanks. Really appreciate it


and yeah it’s so fun.
keeps me feeling well.
 
#38
As a rather crude and makeshift method - I've had some success simply measuring external cabinet walls at close proximity with a standard measurement mic and REW. This will give you a baseline measurement, which you can then compare against after modification.

I used this idea on a Pensil design speaker to identify a resonance around 270hz in the side walls, which I reduced with additional temporary bracing. In saying that, I'm not entirely sure there was any audible difference at the listening position afterwards - maybe if I listened with my ear pressed to the cabinet wall 😉
 
  • Like
Reactions: tone?
#40
Earplay2020 said:
As a rather crude and makeshift method - I've had some success simply measuring external cabinet walls at close proximity with a standard measurement mic and REW. This will give you a baseline measurement, which you can then compare against after modification.

I used this idea on a Pensil design speaker to identify a resonance around 270hz in the side walls, which I reduced with additional temporary bracing. In saying that, I'm not entirely sure there was any audible difference at the listening position afterwards - maybe if I listened with my ear pressed to the cabinet wall 😉
Click to expand...

hmmm.
i had a thought like that as well

good idea.

thanks man!
 
You must log in or register to reply here.
Top Bottom