27th December 2012
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#151 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by Mctwins Hallo...
In your measurement in "A Foor Corner to D Ceiling Corner", did you have the mic inside the wardrobe at tri-corner or outside in front of the door?? Because in this measurement you have flatter freq response and less resonances, which puzzeled me.
In "B Foor Corner to C Ceiling Corner" you have a resonance at 46Hz.
Just want to know how you have the mic positioned, the mic schould be pointed in the tri-corner around 10-15cm. | Yes it was measured inside wardrobe and mic was at 10 cm
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27th December 2012
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#152 | | Lives for gear
Joined: Sep 2011
Posts: 645
| Quote:
Originally Posted by Alejandro Varela Yes it was measured inside wardrobe and mic was at 10 cm
ahaahahaaaa | Thanks for the clarification  , I find this very interesting.
Did you have all the doors of the wardrobe open or closed when you measured? If not...Is it possible to redo the measurements in that tri-corner with all the doors fully open and one with the doors closed.
The speaker in A corner on floor!! Off course.
I suspect that the wardrobe is working like a big Helmholtz resonator in that D corner. This has to be verified when measurements have been done in that tri-corner.
Last edited by Mctwins; 27th December 2012 at 11:02 AM..
Reason: spelling
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27th December 2012
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#153 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by Mctwins Thanks for the clarification  , I find this very interesting.
Did you have all the doors of the wardrobe open or closed when you measured? If not...Is it possible to redo the measurements in that tri-corner with all the doors fully open and one with the doors closed.
The speaker in A corner on floor!! Off course.
I suspect that the wardrobe is working like a big Helmholtz resonator in that D corner. This has to be verified when measurements have been done in that tri-corner. | Wardrobe has 6 doors: 3 upside (little) and 3 downside (bigger). I only leave 1 open, the one that is on corner.
The 3 upside doors has the same compartment. That compartment is fulled of "wretched old things"
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27th December 2012
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#154 | | Lives for gear
Joined: Sep 2011
Posts: 645
| Quote:
Originally Posted by Alejandro Varela Wardrobe has 6 doors: 3 upside (little) and 3 downside (bigger). I only leave 1 open, the one that is on corner.
The 3 upside doors has the same compartment. That compartment is fulled of "wretched old things" | Ok, I see.
Open all the doors and measure again.
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27th December 2012
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#155 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by Mctwins Ok, I see.
Open all the doors and measure again. | Later I will.
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27th December 2012
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#156 | | Lives for gear
Joined: Apr 2009 Location: State of Insomnia, sleepless USA
Posts: 2,177
| Quote:
Originally Posted by Alejandro Varela What do you recommend me?
Maybe adjust the low-end and add reflections treatment to high end?
That's my conclusion, not what it should be... | Getting the low end under control should be the first priority. High frequencies are a cinch to tame/control as they don't carry nearly as much energy. Low frequencies are where the majority of the energy resides (and thus takes the most effort)
Carpet on the walls may be a fire hazard, besides only soaking the highest of frequencies (leaving the mud you're hearing)
There are a variety of methods to tame these frequencies. If you go with porous absorption (THiCK and LOW density) to get your LF tamed, but you find it is over-dampening the HF-- it's relatively easy to dial back in the highs/mids with some scattering or diffusion while leaving the low end still controlled.
You can always use a combination of devices/methods to attack specific problems. Your panel resonators (assuming built correctly) should do a good job, but you will likely need several of them.
Generally, porous absorption is the first thing recommended because it doesn't have a big learning curve/trial-n-error for the uninitiated. Get results with little fuss. I'm not an expert, but i usually recommend starting with the porous, and using the other devices to do the finish work if any specific problems remain. YMMV
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28th December 2012
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#157 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by AwwDeOhh Getting the low end under control should be the first priority. High frequencies are a cinch to tame/control as they don't carry nearly as much energy. Low frequencies are where the majority of the energy resides (and thus takes the most effort)
Carpet on the walls may be a fire hazard, besides only soaking the highest of frequencies (leaving the mud you're hearing)
There are a variety of methods to tame these frequencies. If you go with porous absorption (THiCK and LOW density) to get your LF tamed, but you find it is over-dampening the HF-- it's relatively easy to dial back in the highs/mids with some scattering or diffusion while leaving the low end still controlled.
You can always use a combination of devices/methods to attack specific problems. Your panel resonators (assuming built correctly) should do a good job, but you will likely need several of them.
Generally, porous absorption is the first thing recommended because it doesn't have a big learning curve/trial-n-error for the uninitiated. Get results with little fuss. I'm not an expert, but i usually recommend starting with the porous, and using the other devices to do the finish work if any specific problems remain. YMMV | Thank you very much. AwwDeOhh, really very useful. It must be a sticky...
Just 1 question Tim Farrant. The Lowest Feq Box, should it be yes or yes mounted on the triple corner, cause y 1 corner (A) 1' ve got the AC and havent enough space (34 cm) to put in...Other Box less deep can fit fine, but it will be higher in Freq?
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28th December 2012
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#158 | | Moderator
Joined: Jun 2002 Location: New Zealand
Posts: 2,605
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Yes, it should be OK.
If you are good at carpentry you could make some of these Tim's Corner Slat 2 Helmholtz resonator
__________________ "Opinions are like arse holes, everybody has one" Dirty Harry (Clint Eastwood) Visit Buzz Audio |
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28th December 2012
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#159 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by Tim Farrant | Then I'll leave this corner empty to put a smaller box and put the actual beside.
I' ll make the same on the other corner (B) to maintein proportional view.
Thanks
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28th December 2012
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#160 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter |
Hey McTwins, here is the measurement you asked me: Wardrope open Doors.zip |
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28th December 2012
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#161 | | Lives for gear
Joined: Sep 2011
Posts: 645
| Quote:
Originally Posted by Alejandro Varela | Thanks,
Ok, it looks much the same, closed or open doors, just wanted to clarify if there was any difference. There isin't. I was hoping to see some resonances at 50Hz as in the other corners.
Too me, this is your best corner, why it is so, I don't know, maybe the construction off the wall, rigidy and so on. Leave this corner as it is for the moment.
Corner D can be seen as your reference corner. Corner ABC schould be looking like this and in your listening position. The flattest freq response and minimal resonances compared to the others corners.
I would only concentrate to treat the corner A and B and see what's happens in your listening position.
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28th December 2012
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#162 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by Mctwins Thanks,
Ok, it looks much the same, closed or open doors, just wanted to clarify if there was any difference. There isin't. I was hoping to see some resonances at 50Hz as in the other corners.
Too me, this is your best corner, why it is so, I don't know, maybe the construction off the wall, rigidy and so on. Leave this corner as it is for the moment.
Corner D can be seen as your reference corner. Corner ABC schould be looking like this and in your listening position. The flattest freq response and minimal resonances compared to the others corners.
I would only concentrate to treat the corner A and B and see what's happens in your listening position. | I started hanging boxes at C (finished) & D (little time to end), and then I ll continue with A & B corners :( Quote:
Originally Posted by Mctwins Thanks,
Ok, it looks much the same
... just wanted to clarify if there was any difference...
...as in the other corners.
Too me, this is your best corner...
...Corner D can be seen as your reference corner. | What this mean to you?
If it's the same as the other corners, why should I take it as my reference corner?
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29th December 2012
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#163 | | Lives for gear
Joined: Sep 2011
Posts: 645
| Quote:
Originally Posted by Alejandro Varela I started hanging boxes at C (finished) & D (little time to end), and then I ll continue with A & B corners :(
What this mean to you?
If it's the same as the other corners, why should I take it as my reference corner? | I mean like this.... you don't have to treat corner D. This corner have the best freq response and no resonances. Compare this measurement with corner ABC, here you have resonances and peaks at around 35Hz and 50Hz. Corner ABC schould have the same result as in corner D
Do you understand now.
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29th December 2012
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#164 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by Mctwins I mean like this.... you don't have to treat corner D. This corner have the best freq response and no resonances. Compare this measurement with corner ABC, here you have resonances and peaks at around 35Hz and 50Hz. Corner ABC schould have the same result as in corner D
Do you understand now. | Yes. thank you. I had put boxes in that corner. Must I take off?
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29th December 2012
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#165 | | Lives for gear
Joined: Sep 2011
Posts: 645
| Quote:
Originally Posted by Alejandro Varela Yes. thank you. I had put boxes in that corner. Must I take off? | Don't know, depends if it has changed something when the box is there.
You can measure at LP and see if there is a difference.
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29th December 2012
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#166 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by Mctwins Don't know, depends if it has changed something when the box is there.
You can measure at LP and see if there is a difference. | OK, thank you.
I couldn't hang Box's ceilings at A & B corners cause I' m using a "J Type" aluminum strap and today went to the shop, to buy more, and it was closed.. 
I will finish my boxes next year...
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30th December 2012
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#167 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter |
Hi, I recently read this in one topic.
Can someone explain me what it means? Quote:
Originally Posted by Weasel9992 It's good that it's big...modal issues won't be as prominent, but you'll have to work on low frequency decay time (if you haven't treated the room already). With subs, placement is critical...I prefer using prime numbers like 1/7th the length and 3/7 the width, for example. Don't place it in the middle (usually) or in a corner.
Frank | I musn't place my sub in the middle?
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31st December 2012
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#168 | | Lives for gear
Joined: Apr 2009 Location: State of Insomnia, sleepless USA
Posts: 2,177
| Quote:
Originally Posted by Alejandro Varela Hi, I recently read this in one topic.
Can someone explain me what it means?
I musn't place my sub in the middle? | You place your sub where it works best. But that spot is usually found off-center.
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31st December 2012
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#169 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by AwwDeOhh You place your sub where it works best. But that spot is usually found off-center. | Thank you... I didn't know it!!!
...but how can I find "where it works best"?
My Sub has an option about 0º & 180º... Where it must be placed?
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31st December 2012
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#170 | | Lives for gear
Joined: Apr 2009 Location: State of Insomnia, sleepless USA
Posts: 2,177
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that's a matter of trial and error. Use your Analyst software (REW?).
There really isn't a one-size-fits-all answer, as it is largely dependent on your particular setup/room.
It (sub) doesn't need to be centrally located, as the frequencies it will be pushing aren't directional.
Try the placement(s) you quoted above first, and tweak from there.
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2nd January 2013
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#171 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by AwwDeOhh 
that's a matter of trial and error. Use your Analyst software (REW?).
. | What should I read at REW?
Thanx
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2nd January 2013
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#172 | | Lives for gear
Joined: Apr 2009 Location: State of Insomnia, sleepless USA
Posts: 2,177
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You're looking for linear response across the frequencies.
It helps to calibrate levels (85dB is the SMPTE standard for monitoring levels) so all speakers are pumping the same level and not out of wack.
When you get them calibrated, next you're looking for phase/time alignment between the sub and the satellites. Along with relative location, that's what the 180º switch is for on the sub.
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3rd January 2013
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#173 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by AwwDeOhh You're looking for linear response across the frequencies.
It helps to calibrate levels (85dB is the SMPTE standard for monitoring levels) so all speakers are pumping the same level and not out of wack.
When you get them calibrated, next you're looking for phase/time alignment between the sub and the satellites. Along with relative location, that's what the 180º switch is for on the sub. | Thank you AwwDeOhh. You're the Bible!
Finally 8 Box built & Mounted. (I hadn't cut back earlier ones, 2. And leave at A & B floor corners)
Here are REW's Clean measures.zip Boxed measures.zip |
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3rd January 2013
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#174 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter |
I don't know what to think, but maybe I should rotate B floor box to D Floor Corner. IMHO... Sure I'm wrong!!! |
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3rd January 2013
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#175 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter |
Can someone analyze my new measurements pleaz?
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3rd January 2013
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#176 | | Lives for gear
Joined: Aug 2003 Location: Cork Ireland
Posts: 8,659
| Disappointing
Alejandro, I am very sorry to see this. There is very little effect from whatever treatment you have just measured. There are tiny improvements in the FR and an improvement in one null in the Waterfall. However lower down the Waterfall has become worse.
Tuned or resonant traps are tricky to get right. That is why they are not recommended for DIY. Unless there is obvious tested success and seemingly little possibility of failure due to simple design.
e.g. This works Perforated Panel with Porous Absorber trap
DD
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3rd January 2013
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#177 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by DanDan Alejandro, I am very sorry to see this. There is very little effect from whatever treatment you have just measured. There are tiny improvements in the FR and an improvement in one null in the Waterfall. However lower down the Waterfall has become worse.
Tuned or resonant traps are tricky to get right. That is why they are not recommended for DIY. Unless there is obvious tested success and seemingly little possibility of failure due to simple design.
e.g. This works Perforated Panel with Porous Absorber trap
DD | Really? WOW These is the worst thing I wanna read!!!
Year is lost!!! |
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3rd January 2013
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#178 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter |
Is something that I can do with those boxes?
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4th January 2013
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#179 | | Gear maniac
Joined: Dec 2012 Location: Buenos Aires
Posts: 170
Thread Starter | Quote:
Originally Posted by DanDan | I am reading entire post (and links) but I didn't notice (yet) a rule about certain freq to treat on! I only notice 2 layers with a peace of metal between each layer, isn't it?
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4th January 2013
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#180 | | Lives for gear
Joined: Sep 2011
Posts: 645
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Alejandro....
I really don't like to repeat myself over and over again but here it goes... If you don't take care of the first axiell modal resonances the result will always be like what you have now, absolutely no difference between before and after measurements.
It seems that those boxes is not working.
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