[OB_Newbie]

OB_newbie
Cardboard cc was the first material I used I believe,I could get my hands on all sorts for free at the place I worked at the time,the thinnest was 3mm approx ,this was my favourite.
The main problem with cc was the it sounded like cardboard ,also the sound would travel along the flutes but be blocked going across them ,a bit like the wave breakers that you see at the beach,adding shellac just makes the panel heavier and makes things worse,although I do remember coating the exciter side and noting it helped the sound spread across the back of the panel,coating both sides over damped it,to my ears anyway.
Luckily I discovered eps which is still my favourite ,so far.
I'm afraid I'm going to be showing another couple of panels soon ,one of them my new ply panel and maybe my other harder type panel,if all goes well.
Steve

LOL... more panels... your killin' me here.  Can't wait to see them!

I can see that PVA + water does not work on CC the way I had hoped... I tried to soak them to get the flutes and that resulted in, as you pointed out, a over damped panel.  My old shellac panels hardened really nice after almost 2 years.  I think they would sound much better.  Did you go back to your old shellaced panels after they hardened?   Mine seem like they may sound decent... the knuckle test to the panels had me thinking they may sound good?!? 

Looking forward to more of your panels!

[OB_Newbie]

OB_NEWBIE
Have also pulled out an old eps panel from the loft,an odd shaped one but I haven't thinned the front area ,so could take some measurements then do some thinning and so forth,I now have too many panels to work on at one time,5 in all
As for EQing panels ,I'm trying to make panels that do not need EQing or very little at most,so if we could have the measurements without EQ it would be very helpful.
These last few weeks or so have opened my eyes about the way hard and heavy panels differ from the lighter eps types ,they both need different mounting to produce their best.
Hopefully if all the tests go well I will post the results,just not 100percent sure yet!
Steve

That sounds good Sedge... looking forward to the test.  Do you use pink noise with your RTA?  I ask because while I got good, directional results with mine (1/12 resolution) it was hard picking out small changes.  For instance, I went back to my original 2x2 XPS panels that didn't have rounded corners or edges.  I noticed that, by keeping the corners and edges square, the panels were more rigid.  I took 1 panel and rounded the corners and edges and measured against the original and saw that from 9KHz and up the original had about a 2dB raised level through that entire HF range.  I don't think I would be able to see that via RTA even with 1/12 octave resolution... not with pink noise anyway.  Just thoughts I had when I did measurements on these panels.

My measurements should always show both raw and EQed results (see Reply #2670 on: 29 Dec 2015, 10:02 pm).  EQed results really don't provide much value other than show what can be done with a little carefully applied EQ.  My approach to EQ has changed over time.  Generally, I apply less EQ than I did originally.  I typically don't boost any frequencies and try to only flatted peaks.  Only if there is a broad, shallow dip will I add a little EQ.   

[sedge]

OB_NEWBIE


This is an old pic from my gallery,as you can see a 5db roll of above 10k is easily spotted ,raising this by 2db would show up also,although this might not excite me much ,as moving the Mic around would probably change all that,but it is the large dips and peeks in the room that would interest me the most,as in this old pic .

How they drive the room is very important so seeing them in this 30db window wort's and all is helpful,a 90db window would pretty them up to much,smoothness of response is not what I am looking for .but generally to make sure the panel is covering as much of the frequency between 20hz and 20k as possible without large deviations,but at the end of the day it all comes down to how it sounds ,this next smooth pic was one of my first panels that I was very excited about but as I said at the end of the day it just sounded tooooo smooth

I thought I had it made with the response within a 5db band from 100hz to above 10k and only one or two db down at about 16k ,so I use measurements only as a guideline,but they can  show up bad faults in panels that are less than ideal.
Happy New year all.
Steve

[OB_Newbie]

I thought I had it made with the response within a 5db band from 100hz to above 10k and only one or two db down at about 16k ,so I use measurements only as a guideline,but they can  show up bad faults in panels that are less than ideal.
Happy New year all.
Steve

You got that right brother...only measurements for a guide!!  All of these measurements don't mean that much on their own... both good and bad soundings panels are squiggles and you can not tell what panel would sound good by simply looking at these measurements.

Happy New Year to you all!!
Rich

[osssyvan]

Hi,

Here is graph for 900mm x 600mm x 3,5mm ply panels. Teal is with exciter on the dayton audio proposed position and the pink is one with around 2/5 from side and middle from top as I cut the panels shorter. Red is from dayton position when the panels were still 1200x600 sized.

Interestingly there is still the dip in 8-11k region and cutting the panels seemed to affect the LF suprisingly little.



-Ossi

[sedge]

Osssyvan
Hi
Just a few questions.
What was the distance of the Mic.
Is the scale in 5db increments,it's a bit hard to see.
What exciter was used and how was it mounted.
Did you think the sound changed much between sizes and exciter positions.
Thanks for sharing.
Steve

[Odal3]

Back home from the Holidays and a big box filled with exciters from my latest order awaited me at home! The new year couldn't have started better. Happy new year everyone!

[sedge]

Exspec
I presume that you will be able to have all the panels out from the walls 3to4ft?
If the exciters are the same 10watt cheapo exciters I bought some years ago they will be fine with eps and xps and probably ply.
If ply is used they will be struggling with the movie LF below 50HZ ,so xo above this.
Small poly type panels could also work for smaller rooms but more powerful subs would be needed ,and capable of a good quality of sound up to match the panels xo.
Steve

[osssyvan]

Hi,

Roughly 2m away. I did make too good comparison but both of them have sounded still fine. New charts are 2db steps. The exciter is
DAEX32EP-4.






I think the measurement spikes are not telling the truth. I have to figure out what is happening but I would guess that with that big jumps you would hear something is wrong but it is sounding quite nice. If EQ to max flatness they sound boring.

-Ossi

Osssyvan
Hi
Just a few questions.
What was the distance of the Mic.
Is the scale in 5db increments,it's a bit hard to see.
What exciter was used and how was it mounted.
Did you think the sound changed much between sizes and exciter positions.
Thanks for sharing.
Steve

[OB_Newbie]

Hey Ossi!
Unfortunately, this is the way these panels measure.  In my opinion, measuring with 1/6 smoothing is more telling of how they will sound/tonal balance.  It has been said that our ears are not as sensitive to dips in the response but can more easily identify the peaks.  This I believe make these panels sound very detailed.

I do agree with you that they sound more boring EQed closer to flat.  But then again, insert a smooth, well balanced speaker and listen... they are boring as well.  The panels still sound more clear and detailed, even after EQing, than most traditional speakers. But what sounds best to your ears is always what is most important...  we only need to make our own ear happy!      

I can listen both ways and be happy!

[OB_Newbie]

Back home from the Holidays and a big box filled with exciters from my latest order awaited me at home! The new year couldn't have started better. Happy new year everyone!

Ahhhhh, it is a happy new year huh Odal!!!   YES!!!!!

[OB_Newbie]

Interestingly there is still the dip in 8-11k region and cutting the panels seemed to affect the LF surprisingly little.

Even my tiny 14.5"x12" panels has roughly the resonance frequency IIRC.  The low freq. are not as strong naturally, but the Fs was roughly the same as the larger 24"x30" panels.  I will look for the measurements and post here in a bit...

[sedge]

Osssyvan
I too have been doing some head scratching ever since OB_newbie mentioned the difference between pink noise and I presume swept tone response .
You also say that you don't think your results are telling the truth!
This got me thinking ,so I measured my panels with a sweep test tone and would you believe it ,they differed mainly in the lower end,will post pic later if you wish.
But then I was looking at your pics and suddenly thought ,modal,what if as the single tone moves up through the frequency you are just measuring the panel modal resonances ,nodes and anti nodes.
I then went onto YouTube to remind myself about what happens when panels vibrate ,and found a vid called ,amazing resonance experiment, and the longer version ,resonance experiment,there's also one called ,the pyro panel,worth a look.
I'm thinking random noise could be better ,so as not to start up the resonance modes.
I always have my Mic and room analyser on and the response after playing lots of music usually matches the pink noise quite well.
Your thoughts on this would be greatly appreciated ,it's just a thought but what do you think?anyone.

Steve

[sedge]

Am still having problems uploading pics on my computer ,having to Finnish off on the kindle!
This is at about 2m from a hard but light test panel using pink noise

This is using a swept tone


Note the heavy roll off below about 1k .


This is a ply test panel using pink noise.

The fourth pic is using a swept tone ,note the more jagged up and down response and the drop of about 10db below about 100hz
Steve

[sedge]

there is an interesting company site called soundRight.Org.UK  they have some nice looking panels for pro work  and cardioid subs for PA ,they measure using swept tone and gated pink noise ,there is also some technical papers of interest  for panels and subs,also interesting placements for good spread of LF.
There seem to be more stuff out there every time I look.
Steve

[Gary.M]

there is an interesting company site called soundRight.Org.UK  they have some nice looking panels for pro work  and cardioid subs for PA ,they measure using swept tone and gated pink noise ,there is also some technical papers of interest  for panels and subs,also interesting placements for good spread of LF.
There seem to be more stuff out there every time I look.
Steve

On their website they spell analysis as analisis multiple times. They quote measurements using a calibrated Behringer ECM8000. Signs that this is not a professional outfit. No problem with diy... but that is the level this site seems to be at.

[guest42212]

These days many spelling errors are due to
not having English as a first language.
One could be an audio genius and not be
able to spell ere.

[exspec]

Sorry double post.

[exspec]

Exspec
I presume that you will be able to have all the panels out from the walls 3to4ft?
If the exciters are the same 10watt cheapo exciters I bought some years ago they will be fine with eps and xps and probably ply.
If ply is used they will be struggling with the movie LF below 50HZ ,so xo above this.
Small poly type panels could also work for smaller rooms but more powerful subs would be needed ,and capable of a good quality of sound up to match the panels xo.
Steve

I was hoping I could wall mount but I guess its not possible.

Has anyone tried to use a foam to absorb some backwave? As well, how did the Mission and Wharfedale DML implementations address the issue of wall mounting? I presume the Mission are meant to be set on tables/stands?

Hoping to play some this weekend as I am away for training at the moment. Thanks for all the advice everyone, much appreciated.

[sedge]

Exspec
If you use a 3mm 3x2ft ply  panel, you can mount this on a 1 1/2x2 1/2inch solid wood frame ,this could be used in open space or hung on the wall with good results ,foam could be used between frame and wall to stop rattling,not sure if foam is needed behind panel ,I tried to hold the panel on the wall to see if it needed it,but it sounded ok,it's very difficult holding a panel on the wall listening and trying to measure at the same time.
On that soundRight site there is a paper by Peter mapp and he suggests you can totally enclose the back of the panel with the loss of the rear output ,the choice is yours
You will lose some of the LF but if you are using a sub ,this shouldn't matter.
If using this panel full range with a 10watt exciter I would use a  xo say 48db at 50hz or higher to keep the large amounts of movie LF sound effects well away the poor little exciter,this panel rolls off heavily below 40hz anyway.
All the best.
Steve