[OB_Newbie]

These DML panels are very open, spacious and free of any box resonances... akin to an open baffle speaker. 

Personally, I think they will integrate best with an open baffle speaker but Sedge has good success with a transmission line.  Also, commercially Tectonic used a Heil ATM tweeter (fast rise time/transient response) with their bass panels and Gobel uses a really high-tech DML full-range with conventional boxed woofers to handle bass duties below 170Hz. 

I also think placement in the room is more important than integrating with other types of speakers.  I find that they need more room like an OB for best performance (so why not go ahead a build a small U frame or SLOB under the panels???     )   

[OB_Newbie]

dup

[OB_Newbie]

These DML panels are very open, spacious and free of any box resonances... akin to an open baffle speaker. 

Personally, I think they will integrate best with an open baffle speaker but Sedge has good success with a transmission line.  Also, commercially Tectonic used a Heil ATM tweeter 6KHz and above (fast rise time/transient response) and Gobel uses a high-tech DML really full-range with conventional boxed woofers to handle bass duties below 170Hz.  So many different combinations have been produced so no technical limits to what can be done.

I think placement in the room is more important than integrating with other types of speakers.  I find that they need more room like an OB for best performance (so why not go ahead a build a small U frame or SLOB under the panels???     )   

[snerdly]

I have some exciters from PE  I ordered reading the thread over there...can anyone recommend a size panel for mid range?..I'm not worried about bass...looking for live ambiance..thanks for any reply

[Odal3]

Do you look for 300hz to 5000hz?
I haven't tried a midrange only myself, but to get to 300hz, I would start with maybe something like 2 X2 ft. The panels are easy to modify and cheap to buy so the best way is to play around with them until you find something that sound good in your system.

But...if you haven't heard the bass from the panels, I really recommend to try a larger panel first. Take for example a 2 x 4 panel, and if it doesn't work out you can just cut it in half for your midrange only panels.

Have fun and let us know how it goes!

[OB_Newbie]

I have some exciters from PE  I ordered reading the thread over there...can anyone recommend a size panel for mid range?..I'm not worried about bass...looking for live ambiance..thanks for any reply

Hello snerdly, just curious as to the intended use? 

[sedge]

I too have been away for a few days holiday ,just got back,there's a lot of questions,not sure where to start.

Shellac.
It might still be going through it's ageing process? Can't wait a year though,as it is at the moment it adds weight and dampens the panel ,a bit like doping a paper cone,for me not so good as it makes the sound smoother but softer with loss of detail.
As for the pva treatment ,I don't actually regard this as damping if anything it does the opposite ,I first noticed this when used on cc ,the pva helped spread the sound across the panel and helped the panel sound less cardboardy .
It did the same sort of job to the bog standard eps ,but now with the horrible sounding skin removed and replaced with pva ,it's a win win situation.
My TLS have doped cones ,they sound great with jazz or classical music ,but put on some heavy rock and they start to sound like my nan knitted them from old pair's of socks!
Steve

[OB_Newbie]

I too have been away for a few days holiday ,just got back,there's a lot of questions,not sure where to start.

Shellac.
It might still be going through it's ageing process? Can't wait a year though,as it is at the moment it adds weight and dampens the panel ,a bit like doping a paper cone,for me not so good as it makes the sound smoother but softer with loss of detail.
As for the pva treatment ,I don't actually regard this as damping if anything it does the opposite ,I first noticed this when used on cc ,the pva helped spread the sound across the panel and helped the panel sound less cardboardy .
It did the same sort of job to the bog standard eps ,but now with the horrible sounding skin removed and replaced with pva ,it's a win win situation.
My TLS have doped cones ,they sound great with jazz or classical music ,but put on some heavy rock and they start to sound like my nan knitted them from old pair's of socks!
Steve

Hey Sedge, I completely agree on the PVA:water treatment.  XPS is over damp off the shelf.  A panel treated with the magic sauce Is more rigid and the otherwise soft and "fuzzy" character is replaced with a more natural sounding panel with detail but is rarely harsh.  Initially, this was one of the more notable characteristics of the panels as the treatment cured and the exciters broke it... even on poor recordings that otherwise sound harsh.

  If you ever get a chance to build another set of bass bins, I can't recommend an option more than an open baffle.  Clean, clean, clean.  I can't listen to a boxed speaker after listen to my open baffle speakers.  It's amazing how much of an affect a box has on the sound quality.  OB is such a nice mate for these.  To boot, they are very easy to build... much like these panels.   

[irishpatrick33]

Can somebody help me measure frequency response?

So I did a controlled experiment with 12 different materials and a Dayton NXT exciter rig. I ran a linear sine wave 1-20,000Hz through my amp and recorded the speaker with an iPhone from 1" away (I know, not ideal but I work with what I've got).

Anyway, I analyzed the recording with Audacity and got some kind of frequency response graph. However, I am not sure if I am doing this right--especially since the graph seems to change dramatically when I make changes in that Audacity window. Also, I don't know how to compensate for mic or room. Does that matter?

My goal was to help us all out. I have spent my time and money to figure out what materials work best through science. But I am a bit over my head and can't finish the work without some help. Any would be appreciated.

[OB_Newbie]

For a cheap and convenient "starter" system, it hard to beat the Dayton Audio iMM-6 Calibrated Measurement Microphone for iPhone iPad Tablet and Android along with the Audio Tools app. I also have a 1/12 octave RTA ($4.99) which is pretty reasonable resolution all things considered.  You will also need one of the many (free) freq. generators.  I use pink noise to get a general idea of the response.

The DA mic is calibrated and you use AT to import the cal file.  You can't compensate for the room with this simple setup.  For most accurate "measurements" you should make measurements outside.
 
But this is just handy and can be wiped out for quick tests and certainly gets you into the ballpark as to what is going on with the panels from a freq. response perspective.

Sounds like you have been busy!!  Very interested to hear about panel materials, suspension and sizes used and some of the insights you gleaned.  Did you have a favorite or a couple that stood out? 

[snerdly]

First I want to say  this is fun..I couldn't get home depot to cut the xps panels for me the guy told me they can only  cut wood on the panel saw..no  big deal... I got the 2x2 project panels did a quick sand and just held the exciter on to the panel...it's kind of shocking when you hear the quality sound coming from a foam panel..anyway I'm at the point of coating these ...so I'm wondering do you sand the exciter area on the panel thinner? Jut not sure..I intend to use these to accent the Kairos (Jeff B.) speakers I built..I'm running all my music off a laptop into a usb DAC and into the sure 3118 monoblock cards..so are you supposed to thin down the exciter area?

[OB_Newbie]

Yo snerdly!  It is indeed fun and more instant gratification... especially at the beginning.  Addicting.

Just to say, make sure you really sand off the skin of the XPS... it is more than just a matter of "roughing" up the skin that you might do to a surface to make paint stick for instance.  Wouldn't wsnt you to go through the PVA:water treatment only to resand (noooo, I've done that personally :- ).

I typically sand lightly around where the exciter will be mounted.  I light hand sand is all that is needed.

Are you rounding the corners and quarter rounding the edges?  I didn't on my first few panels as I just wanted to hear the panels.  But it really doesn't take long.  To round the corners I use a bowl to mark where to cut and just use a steak knive to make the cut.  It's rough but the palm sander makes quick work making a very nice and smooth corner.  Rounding the edges takes more time as its rough with the router just getting 'close' and the rest is hand sanding.

That's silly at your Home Depot... hopefully the next guy will make the cuts for you.

Let's us know how it goes!

[irishpatrick33]

For a cheap and convenient "starter" system, it hard to beat the Dayton Audio iMM-6 Calibrated Measurement Microphone for iPhone iPad Tablet and Android along with the Audio Tools app. I also have a 1/12 octave RTA ($4.99) which is pretty reasonable resolution all things considered.  You will also need one of the many (free) freq. generators.  I use pink noise to get a general idea of the response.

The DA mic is calibrated and you use AT to import the cal file.  You can't compensate for the room with this simple setup.  For most accurate "measurements" you should make measurements outside.
 
But this is just handy and can be wiped out for quick tests and certainly gets you into the ballpark as to what is going on with the panels from a freq. response perspective.

Sounds like you have been busy!!  Very interested to hear about panel materials, suspension and sizes used and some of the insights you gleaned.  Did you have a favorite or a couple that stood out?

So is all my testing garbage? I can't use the recordings to get a decent idea about material's frequency response? I don't plan to spend any more money on hardware or software.

[sedge]

Snerdly
Even on small panels (9x12ft x5mm) ,the response is not far off full range with acoustic music as long as it is not close mic,ed .
The problem with using a full range panel with a multi drive unit speaker is the xo and drive unit phase ,they usually reverse the connection on the tweeter or midrange to get rid of dips or peeks at xo,so the phase will be wrong for one or the other,that is why you should have the same speakers for surround speakers in theory.
I thin the area in front of the exciter on my panels,I have ripped apart one of my old test panels to do some quick testing,will post some pics tonight if I get a chance.

Irishpatrick 33
Sounds very complicated , audacity isn't the easiest software to use,I have played around with it but wouldn't say I understand how to use it,I've only used it for recording LPs .
As I have said, I will post some pics so that you will know what fr response to expect if you follow my construction guide.

[sedge]

found this old test panel and cut off the wood with a bread knife ,don't tell er indoors!





a bit messy but will do.

this is about 2ft from panel.

this is about 12ft into the room,the lower response was peek hold but at about 4ft or so to the left resting on chair,the hf mirrors the top line well,all around the room in fact even to the side.

this is an old bog standard panel from my gallery for comparison .
not perfect but getting better,
steve

[sedge]

I had so many problems setting up this panel, could not sort out the problems without ripping it all apart and starting from scratch, so mad do with what I had, I nearly gave up and chucked  it in the bin,but given all the problems not a bad response.
but the main thing is the sound improvement ,more up front and easy sounding.
all my pics are of a 30db window a 60db or more would look so much better but would not help me see the problems.
the exciter is in the centre of the width and 2/3 the height .
this was very slap dash but shows the hf above 10k is attainable .
steve


60db snapshot

[sedge]

To all
As to the type of LF reproduction,this I think is a very personal choice,but I think for these exciter panels you must make sure that whatever you use ,that it does not boom or have any bad coloration and can produce cleanly ,loudly without strain,in other words does not draw attention to itself .
I have an old pair of Ditton 44s and used them (the12inch bass that is)to help with the LF below 300hz on pair of my 12x9inch panels,the sound was not very good,it wasn't until I turned the panels off that I could hear the 44s cabinet banging and rattling ,it was way out of its power range,hadn't noticed this before with the 44s because everything else got pretty nasty before be the cabinets got to this stage.
These panels can go very loud and have huge dynamics , the LF driver and cabinet must be able to handle this or the sound will suffer.
Snerdly
As a matter of interest I was looking at the kairos web site and noticed the dome tweeter ,  Jeff b says it is special in that it has a dimple in the centre which is attached to the base ,this prevents the centre of the dome vibrating out of control (tin can effect) and causing frequency anomalies ,cancellation and peeks ,I have always wondered about this problem with domes.
I use a similar method to sort out the noise ,distortion,harshness,tin can effect,whatever you want to call it on my panels,before I used to use a very small blob of bluetak in the centre ,this improved fr response but to me it sounded restrained,slowed things down,too smooth,for me ,the less you do to the panel the better it sounds.
As with foam ,I use as small amount as possible to suspend the panel,the foam must be very soft and not have a sound of it's own,New foam has a rasping sound (that old scratch test again)that is why I use old dish sponges,the foam has started to breakdown and loose its stiffness,much softer,the foam strip can be as long as you like ,it can match the thickness of the 1inch panel ,I use pva to glue to the side edge of the panel, 1 or2inches wide depending on weight of the panel,it's so easy and you can change panels so quickly,I have used clothes pegs to clamp the foam to my supports ,like hanging out the washing
Steve

[sedge]

I'd like to point out that I don't spend all my time in the kitchen washing clothes and cleaning dishes................................. .....i don't have time,not with all the house work I have to do

[OB_Newbie]

I'd like to point out that I don't spend all my time in the kitchen washing clothes and cleaning dishes................................. .....i don't have time,not with all the house work I have to do

Giggle, giggle...

[dbishopbliss]

Its been longer than I expected but I finally got around to measuring two 24x24x1 XPS panels.  One with shellac and one without. The measurements don't really look that different, but the shellac version does sound less "fuzzy" (as someone else has described it). I was going to play with the dimensions next but since people insist PVA is better than shellac, I think I will try that first.