[sedge]

This is one of my old smaller xps panels that I put shellac on,looks very similar to the one posted on parts express site.except mine looks like crap of course,this is the extent of my diy skills ,a couple of dobs of hard as nails and Bob's your uncle.

These are some old panels I shoved in the garden shed about 6years ago ,you can see the trouble I went to to try and stop the panel noise problems I was having,thought I would get them out again and see if if I could now solve the problem ,just for curiosity,and to try out some other idea's I've had,might even buy another 3mm  6ftx2ft ply panel to see how it compares to the 2x3ft panels

One of the 2x3ft panels actually goes down to at least 20hz strongly in my room,that's as low as my Behringer display goes,not expecting the old smaller panels to do this of course ,but will be interesting to see what they can do.
Steve

[sedge]

ABELMA
I too have used a similar method to mount my exciters on poly panels,I used a cube of xps and used masking tape with  foam attached to stop the tape from buzzing.
I have also noticed that having the wire's attached to the sides puts the exciter out of balance on large movements ,you can see the exciter rocking ,this is on my 10watt exciters,am thinking of modifying this.
If mounted on a spine no problem of course.
This rocking and buzzing usually ends with the wire from the exciter terminals breaking ,this has happened many times,I have one on its way out at the moment ,on one of the ply panels ,it's still playing but makes curious noises on loud LF,sometimes I've spent ages trying to find what's making the noise, only to eventually find the wire has fallen off
Steve

[Abelma]

-

[exspec]

Has anyone built a 5.1 system using these panels? I am aware of commercial offerings of days past, but am curious if there is a different approach I need to take if considering a HT build.

My plan is to build my panels approximately 24"x30" but this may change. I am using a receiver that allows a 200hz XO point to the subwoofer and am hoping I can EQ a bit of the response via its built in DSP.

What is the consensus on mounting the panels? It appears that less contact with a frame is best. If those using no frames are happy, what is it that you use to mount them or support them in their mounted positions?

Sorry for all the questions.

[sedge]

Exspec
What material are you thinking of using for your panels?

[exspec]

Sedge,

I was thinking of some XPS. They have it at Home Depot here, in various thicknesses.

I originally wanted to make some stereo panels for a wide band midrange driver, but that project is on the back burner, and I have a 5.1 Receiver and a subwoofer, so figured it would be an interesting experiment. For some reason, I am thinking I will be happier with a home theater setup given that the receiver has DSP functions and the crossover works upto 200hz.

Based on reviews of peoples experiments with DML in HT setups, its worth attempting. Getting them to look decent will probably be a challenge as well.

Note: I am using the PE $3 buyouts - but am planning on upgrading if proof of concept goes as planned.

[OB_Newbie]

Hey exspec!
Member TXATC in this thread has built a DML HT system but can not remember if he finished the frames, etc.  He did report excellent results however.  Odal has listened to his panels in a HT setup (just mains IIRC) and has also said they are very realistic and do recreate the venue (nature/city scenes and noises, etc.) very well.

I'm starting my framed panels tomorrow which will consist of simple .75" x 1.25" pine with corner braces also made of pine.  Panel suspension will be .5" open cell foam that will be glued to the frame with Velcroed between the foam and panel.  Suspension foam and XPS panel will be treated with black ink.  Ink and ink/water for foam, water:ink:PVA for the panels.  The frames will then be wrapped in black grill cloth.

200Hz is pretty high cross over point and if that is what you are crossing at, you can make panels smaller than 24" x 30" IMHO.  Even my tiny 14.5" x 12" panels get flat to 200Hz and they still float a huge soundstage (they do totally disappear).  I'd go bigger than these tiny panels but just use that as a guide as you consider your living space, mounting, etc.

Hope to report back tomorrow with progress.

[osssyvan]

Hi exspec,

I've used my ply panels as 2.0 for movies and they work really well. Very realistic soundscape. Getting roughly to 100 hz should doable quite easily but HT type effects that you feel could be too much for LF. You can get quite realistic LF though.

-Ossi

Sedge,

I was thinking of some XPS. They have it at Home Depot here, in various thicknesses.

I originally wanted to make some stereo panels for a wide band midrange driver, but that project is on the back burner, and I have a 5.1 Receiver and a subwoofer, so figured it would be an interesting experiment. For some reason, I am thinking I will be happier with a home theater setup given that the receiver has DSP functions and the crossover works upto 200hz.

Based on reviews of peoples experiments with DML in HT setups, its worth attempting. Getting them to look decent will probably be a challenge as well.

Note: I am using the PE $3 buyouts - but am planning on upgrading if proof of concept goes as planned.

[exspec]

OB_Newbie,

Thanks for your reply. I did notice that TXATC has a similar HT setup. I took note of the size of his panels. My reasoning for the 200hz XO point was due to my reading of the Mission units which were dependant on the subwoofers ability to go up to 200hz. My existing sub is a small 8" Yamaha I got to compliment a soundbar and it seems to have high output down to about 40hz - good enough for experimenting. It plays up to 200hz.

It's good to know that the panels will not have too much issues with playing lower - may actually allow me to set it up even better than hoped.

In regards to the HF, what suggestions might you have to have them extend without much rolloff? Thinning the panel at the attachment point on the front side seems to be the go to way, and CLS (i believe) on another forum suggested trying a wooden biscuit. It's something to ponder, as I know HF content is important.

[Odal3]

The panels definetely works really well for HT. I havent tried it yet as a center since I haven't figured out how to place the  panel in a WAF friendly manner without blocking the TV stand where I have all the amps and misc components.

But yes, the panels (with subs) sounds super - I encourage everyone to try playing the type of scenes OB-newbie mentioned or something like a gun shoot or the drumming and talking scenes in whiplash. Maybe what could be slightly better is sharp/shrieking/metallic type of sounds you hear in Sci-fi movies. Perhaps because these type of sounds are mixed to be  very direct where panel speakers have more of a diffused sound wave.

Question for the HT crowd - should HT speakers in general be more direct or have a more omni character?

I wouldn't cross the sub that high - especially if you only have one. The problem is that the bass can be localized that high (not omni) and make the soundstage unbalanced. Make the panels larger instead and cross it lower. Just because the spec on the sub says it can play to 200hz it doesn't mean it will play that high nicely. There are only few subs IMHO that can play that high and then they still need to be two in stereo placed closely to the mains. The simple and crude way to test how high you can cross it when you only have one sub is to only play the sub alone and see if you can localize where the sound is coming from.

[OB_Newbie]

OB_Newbie,

Thanks for your reply. I did notice that TXATC has a similar HT setup. I took note of the size of his panels. My reasoning for the 200hz XO point was due to my reading of the Mission units which were dependant on the subwoofers ability to go up to 200hz. My existing sub is a small 8" Yamaha I got to compliment a soundbar and it seems to have high output down to about 40hz - good enough for experimenting. It plays up to 200hz.

It's good to know that the panels will not have too much issues with playing lower - may actually allow me to set it up even better than hoped.

In regards to the HF, what suggestions might you have to have them extend without much rolloff? Thinning the panel at the attachment point on the front side seems to be the go to way, and CLS (i believe) on another forum suggested trying a wooden biscuit. It's something to ponder, as I know HF content is important.

Yo exspec, you can certainly play with different XO frequencies but as long as the sub can cross lower, I wouldn't go higher than 100-125Hz if possible.  Not ideal, but I've crossed as high as 150Hz without to much localization issues but that is higher than I would want.

In regard to XPS measurements... disregard my earlier measurements... totally my bad.  I was in a rush before company came over and didn't scrutinize the results and was paying more attention to the differences between panel materials and exciters.  The inaccurate measurements were the result of lost soundcard/mic settings in REW.      My previous measurements with Omnimic and RTA where extended.  I measured last night (into early morning actually  ) and while I don't have the old Omnimic measurements to compare too, in the process of EQing the XPS panels, the parametric EQ settings/frequencies that I established with Omnimic matched perfectly with the REW measurements so I CAN say that these measurements are very close to what I previously got with Omnimic.

I measured and EQed cardboard, ply and XPS panels and XPS has very good HF response which needed no boosted high freq. EQ... just smoothing larger peaks/dips.  As a matter of fact, if XPS is EQed flat they sound thin and tilted up.  I initially thought that the tilted up power response was responsible for this but I am not sure of that after last night.  Cardboard and ply when EQed flat didn't sound hot as XPS so this appears to be a characteristic of XPS!?  Possibly due to the fact that XPS is so incredibly light and rigid.  Very sensitive, can play loud and with more detail than ply and cardboard.

On to HF response for ply and cardboard... Thruster on 24x30 ply needed approx +7dB to go flat(ish) to 17KHz.  The Dayton 24 watt high efficiency exciter on 18x26 cardboard has a tilted up HF response and had to reduce HF for a flat response. Cardboard is smooth but not in love with how they sound at this point but want to get more time on them before I can say for sure. 

Here are the measurements for a raw XPS panel and one that is crossed at approx. 100Hz and EQed "flat":



My opinion, even the 32mm Thruster has quite good HF extension on 1" XPS and sounds good as well.  However thinning it is not a bad idea and am planning to do that on the panels I *should* be working on right now.     I will also be using lower powered exciters on these as the XPS panels are so efficient and the higher power is really not needed it appears.  While really not needed, the smaller voice coils will only improve the extension.

[Odal3]

Albema - those looks great. Congratulations to finishing them to your liking! I'm sure they sound great.

OB - I also get the peak with the 24W exciters which was an interesting and I guess good surprise on thick ply. I don't have access to the measurements at the moment but think the peak was around 17k

[Odal3]

Sedge - you must be close to setting up a museum with all your panels. Always learning something new from your posts. Thank you!

[OB_Newbie]

Albema - those looks great. Congratulations to finishing them to your liking! I'm sure they sound great.

OB - I also get the peak with the 24W exciters which was an interesting and I guess good surprise on thick ply. I don't have access to the measurements at the moment but think the peak was around 17k

Same here Albema... congrats on another successful DML panel build!!!

I should be building today but after 5 hours of shoveling and snowblowing mine and other's driveways in the neighborhood I've decided to take it easy and listen to the panels this afternoon and evening.  Now another admittance     After hooking up the CD player and listening to them with music I noticed that they sounded bass heavy... ummmm... the loudness button on my Luxman integrated was on.  Soooooooo... once again the measurements are not accurate.   

Can't tell listening to sweeps or after being EQed and crossed but when I went to listen full range I was impressed by the bass output.  Silly boy.  Anyway, had to share... what a day!!

I also got out the KEF's after a long hiatus and am listening to them now.   It is easy to forget certain performance aspects, tonal balances or coloration of a speaker until you inset a new speaker into the system.  I was disappointed by the panels performance when switching from the KEFs and was anticipating that again and be reminded of their neutrality and overall excellent balance and performance.  Strangely, this was not the case.  I was taken back by the boxy resonances and lack of detail and general clarity of the panels.  I asked my wife what she thought and she said the same thing... not as clean as the panels; "vocals are not as clear".  These were the aspects that I enjoyed most when I first put the paneling in place.  The lack of a box has great value to speaker performance.  Beyond that, initially coming from an resonance free Open Baffle system, even compared to them (which uses the highly regarded Tang Band W4-1879 4" full range driver) the DML panels have greater clarity and detail.  Despite the XPS panel coloration's and other tonal considerations these panels absolutely hold a position in the listening room.   

After a few hours of listening, I am really enjoying the Q500s. A really nice sounding speaker with the coherence of a high quality full range speaker (which I favor)... impressed by what KEF has been doing recently.  But I am beginning to fight switching back to the panels for a quick hit of panel magic.      Still feeling love for these flat panels!!! 

[exspec]

Thanks for the extra inputs, much appreciated.

I agree with the assertion that subs should be crossed low and not high into the high 100's. My open baffles tend to stay under 100, and I love it that way. Once I am certain the panels will work, I will contemplate building a pair of quality subs.

In regards to HF extension, if using XPS, it sounds like I may not to add anything, and just try them full range as is. My lack of measurement equipment is going to be an issue, but will address that in time as well. I have pondered crossing over a small tweeter in the high teens if lacking some of that top end sizzle.

Am I best pursuing an XPS panel? (For the record - and my stupid brain - is XPS the stuff thats pink and dense, or is it the white foam like they pack electronics etc in? - Sorry, I keep getting mixed up)


I am hoping to pick up some panel material soon. I suppose some experimentation will be required before finishing the panels - this allows me time to plot something special for a finish

[OB_Newbie]

Sedge - you must be close to setting up a museum with all your panels. Always learning something new from your posts. Thank you!

+1  Steve... you amaze me... every time I think I've seen them all, you pull out yet another panel!!

What are your thoughts on cardboard(CC)?  I built a smaller pair (roughly 18x26) from a Dollar Tree tri-fold board and treated with PVA:water to make them more rigid.  I tried to soak the panel hoping that it would get into the flutes...was not interested in treating the flutes as I did earlier with shellac... a lot of work.  So PVA:water treatment on the surface it was.

The results so far... they measure smooth.  Very easy to EQ flat and doesn't require much EQ to do so.  The one thing that strikes me though, is a lack of transparency... its like the Cc absorbs the energy and is not rigid enough to be excited across the entire panel?!?  Easy to localize and the sound comes more from the exciter.  Ply and XPS does a great job of disappearing... CC not so much.

This is pretty low quality CC so very curious to hear your assessment.   

[OB_Newbie]

Thanks for the extra inputs, much appreciated.

I agree with the assertion that subs should be crossed low and not high into the high 100's. My open baffles tend to stay under 100, and I love it that way. Once I am certain the panels will work, I will contemplate building a pair of quality subs.

In regards to HF extension, if using XPS, it sounds like I may not to add anything, and just try them full range as is. My lack of measurement equipment is going to be an issue, but will address that in time as well. I have pondered crossing over a small tweeter in the high teens if lacking some of that top end sizzle.

Am I best pursuing an XPS panel? (For the record - and my stupid brain - is XPS the stuff thats pink and dense, or is it the white foam like they pack electronics etc in? - Sorry, I keep getting mixed up)


I am hoping to pick up some panel material soon. I suppose some experimentation will be required before finishing the panels - this allows me time to plot something special for a finish

Hey exspec,
You have the sub situation well at hand. Good to see another open baffle guy in the thread. OB bass panels are great companions for these panels.

Yeah, XPS is the pink Owens Corning Formular sheets that are available at all Menards, Lowes, HD, etc.  Cheap, sounds good and uber light weight.  Probably the best option for HT as it gives you more options to mount to walls if that is required.  I'm afraid my inaccurate measurements confused XPS performance.  I have the 16ohm exciters that you are going to use but I've never dropped them on a panel. They are really small and I wonder if they will do a good job.  If you do go with 1/2" XPS will be your best option.  You might also consider multiple exciters per panel.

But to be honest, if I were to do it, I might opt for the Dayton Audio DAEX25FHE-4... cheap and perform pretty well.  The mid-range is a little hotter then some of the other exciters but if you have EQ available (you mentioned DSP?) it would be a no brainer in my opinion if you are going through the effort to get the XPS and built some panels.  Pink panels... get some black ink and add it with the water in the water:PVA treatment... will be easier to hide behind grill cloth.   

Gotta run!

[Abelma]

T

[sedge]

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

[sedge]

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