DIY Flat Panel Speaker Love

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Hey Unbiasedsound,
How did you prepare your EPS panels? What size are they and did you listen to them on stands or? If not on stands, how did you suspend them for listening?

Bought some cheap EPS and curious what you built specifically.

Later boys!

I am pretty much burnt out right now lol....The eps I bought at lowes is probably the standard normal grade, while my bertagnis use a higher grade of eps exactly which grade I am not certain but it is harder then the grade I currently have. Ive learned there are 5 grades of eps with each one being stiffer/harder/stronger then the next there is SL, S , M , H and VH. If I had to guess my bertagnis would probably be at least in the M grade or as high as the VH. Until I can acquire some H or VH grade eps I am going to take a break from this project, because the sound from these low grade eps does not come close to the sound of my bertagnis.


I have also read the whole 130 something pages on that other forum about nxt panels. I have seen zygadr go from claiming Gator board to be the best then to VH eps to plywood then to cardboard and back again to vh eps. I think the problem lies when there is no DIRECT comparison of a set standard, hence why I use my Bertagnis as my DIRECT comparison standard. If I did not have my bertagni speakers to compare them too I would probably believe or say that my DIY panels sound pretty good after listening them for prolonged periods of time, but as soon as I switch them back to the bertagnis the difference is as clear as night and day as in a blind fold test I would always be able to pick out which speaker was playing. My goal is to create a panel where I would have a hard time telling which speaker is which. If I can get some hv eps material then hopefully the sound will be even closer to the sound of my bertagni speakers. I have to also take into account that it could be this particular exciter itself as I have not tried any other exciters. If the Ultras were more durable I would of opted to buy them as my first choice. If all else fails like my gal said I could just buy another pair of bertagni speakers where ever they are available.

[Kornbread]

Re: DIY Flat Panel Speaker Love

[QUOTEI have also read the whole 130 something pages on that other forum about nxt panels. I have seen zygadr go from claiming Gator board to be the best then to VH eps to plywood then to cardboard and back again to vh eps. I think the problem lies when there is no DIRECT comparison of a set standard, hence why I use my Bertagnis as my DIRECT comparison standard. If I did not have my bertagni speakers to compare them too I would probably believe or say that my DIY panels sound pretty good after listening them for prolonged periods of time, but as soon as I switch them back to the bertagnis the difference is as clear as night and day as in a blind fold test I would always be able to pick out which speaker was playing. My goal is to create a panel where I would have a hard time telling which speaker is which. If I can get some hv eps material then hopefully the sound will be even closer to the sound of my bertagni speakers. I have to also take into account that it could be this particular exciter itself as I have not tried any other exciters. If the Ultras were more durable I would of opted to buy them as my first choice. If all else fails like my gal said I could just buy another pair of bertagni speakers where ever they are available.[/QUOTE]


That was one of the big reasons I wanted to get some raw measurements out there. Not everyone 'hears' the same. If all one were ever exposed to was WalMart HiFi, then just about anything that made noise would sound good. :o

It's been about a month since PE last told me they were escalating my issue (exciters dying after light use) to a superior. It looks like I may be eating those Dayton DAEX32EP-4's. That's a shame as I've put some time and material into furthering this type of speaker, and possibly helping their sales.

[rmeinke]

Re: DIY Flat Panel Speaker Love

I am pretty much burnt out right now lol....The eps I bought at lowes is probably the standard normal grade, while my bertagnis use a higher grade of eps exactly which grade I am not certain but it is harder then the grade I currently have. Ive learned there are 5 grades of eps with each one being stiffer/harder/stronger then the next there is SL, S , M , H and VH. If I had to guess my bertagnis would probably be at least in the M grade or as high as the VH. Until I can acquire some H or VH grade eps I am going to take a break from this project, because the sound from these low grade eps does not come close to the sound of my bertagnis.


I have also read the whole 130 something pages on that other forum about nxt panels. I have seen zygadr go from claiming Gator board to be the best then to VH eps to plywood then to cardboard and back again to vh eps. I think the problem lies when there is no DIRECT comparison of a set standard, hence why I use my Bertagnis as my DIRECT comparison standard. If I did not have my bertagni speakers to compare them too I would probably believe or say that my DIY panels sound pretty good after listening them for prolonged periods of time, but as soon as I switch them back to the bertagnis the difference is as clear as night and day as in a blind fold test I would always be able to pick out which speaker was playing. My goal is to create a panel where I would have a hard time telling which speaker is which. If I can get some hv eps material then hopefully the sound will be even closer to the sound of my bertagni speakers. I have to also take into account that it could be this particular exciter itself as I have not tried any other exciters. If the Ultras were more durable I would of opted to buy them as my first choice. If all else fails like my gal said I could just buy another pair of bertagni speakers where ever they are available.

Hey UBS,
I'm still very interested in your panels and what you have done. Maybe I missed the post or posts, can you point me to the post about your panel details, how you have them setup and positioned? Would appreciate it.

As you point out, its hard to determine what panel material, exciter for what implementations and listening preferences are best. I proposed a common build (or builds as it progresses) that could be used as a reference but that didn't get much traction. Establishing a common reference or set of reference panels might be easier said then done, honestly, as I use EQ for proper balance. To make the best panels, I still feel EQ is required. So some type of EQ would/should be part of the reference build.

To defend Ziggy, that was over a 6 year span with different configurations and new exciters along the way (they got more powerful). Like any other new technology with no real historic data, there was large portions of learning, mistakes, twists and turns for sure. I felt the same way when I first read it but after building lots of panels with different materials, sizes, exciters, etc. I understand it and appreciate it a lot more now. Still learning.

[Dirk]

Re: DIY Flat Panel Speaker Love

Rich, one of these days I gotta hear/see what you're up to. I'm sure Marty would, too. :D

[rmeinke]

Re: DIY Flat Panel Speaker Love

Yeah, we really ought to get the fellas together some time. I'm surprised by the number of folks we have on the forum... Marty, Chris R, yourself just to name a few of the regulars around here. There are a few others but can't remember their forum names. Good turn out for the Valley either way...

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Hey UBS,
I'm still very interested in your panels and what you have done. Maybe I missed the post or posts, can you point me to the post about your panel details, how you have them setup and positioned? Would appreciate it.

As you point out, its hard to determine what panel material, exciter for what implementations and listening preferences are best. I proposed a common build (or builds as it progresses) that could be used as a reference but that didn't get much traction. Establishing a common reference or set of reference panels might be easier said then done, honestly, as I use EQ for proper balance. To make the best panels, I still feel EQ is required. So some type of EQ would/should be part of the reference build.

To defend Ziggy, that was over a 6 year span with different configurations and new exciters along the way (they got more powerful). Like any other new technology with no real historic data, there was large portions of learning, mistakes, twists and turns for sure. I felt the same way when I first read it but after building lots of panels with different materials, sizes, exciters, etc. I understand it and appreciate it a lot more now. Still learning.

My Panels are 20 inch by 36inc. 1inch thick EPS from lowes. Panels have been sanded on both sides with rounded corners with the 50/50 glue and water mixture on both sides as well. I made a rectangle shaped wooden frame using 1inchX2inch wood with a bar in the middle as well as one on the top corner to hold the exciters in place as I am using 2 exciters per speaker just like my bertagnis. I was going to build some 2 inch stands for them like my bertagnis but choose not too due to them not sounding to my satisfaction...They are positioned around 2ft. out from the back walls and about 8ft. apart.

Like I've said before I use my Bertagni speakers as my reference speakers to compare them too as I use the A and B speaker switching for direct comparison. I also believe from first hand experience that they do sound better with eq, even my bertagni speakers sound better with eq....but as of now my current diy panels do not come close to my bertagnis even with eq as the clarity is just not there. My next goal is to get some good quality EPS most likely the VH grade. I would also like to try some honeycomb material just like they use in the podium speakers.

Dont get me wrong I was not putting down ziggy in any way I was just stating one needs a DIRECT standard reference to compare it too or else everything can sound good like Korn bread mentioned. I did some comparison experiments using some of my family relatives as the judges. First I played my DIY panels and asked them how it sounded. With nothing to compare it too all of them said it sounded pretty good compared to what ever speakers they last remembered. BUT when I switched to my bertagnis and then back to my diy panels I asked them how do they compare and all of them said the bertagnis were hands down better. I actually commend Ziggy on all his galliant efforts to finding the right/best design/sound for these panels and doing a lot of the experimentation. I also have read if I am not mistaken that Ziggy has passed? If so my condolences for his family and loved ones.

[Fshow]

Re: DIY Flat Panel Speaker Love

My Panels are 20 inch by 36inc. 1inch thick EPS from lowes. Panels have been sanded on both sides with rounded corners with the 50/50 glue and water mixture on both sides as well. I made a rectangle shaped wooden frame using 1inchX2inch wood with a bar in the middle as well as one on the top corner to hold the exciters in place as I am using 2 exciters per speaker just like my bertagnis. I was going to build some 2 inch stands for them like my bertagnis but choose not too due to them not sounding to my satisfaction...They are positioned around 2ft. out from the back walls and about 8ft. apart.

Like I've said before I use my Bertagni speakers as my reference speakers to compare them too as I use the A and B speaker switching for direct comparison. I also believe from first hand experience that they do sound better with eq, even my bertagni speakers sound better with eq....but as of now my current diy panels do not come close to my bertagnis even with eq as the clarity is just not there. My next goal is to get some good quality EPS most likely the VH grade. I would also like to try some honeycomb material just like they use in the podium speakers.

Dont get me wrong I was not putting down ziggy in any way I was just stating one needs a DIRECT standard reference to compare it too or else everything can sound good like Korn bread mentioned. I did some comparison experiments using some of my family relatives as the judges. First I played my DIY panels and asked them how it sounded. With nothing to compare it too all of them said it sounded pretty good compared to what ever speakers they last remembered. BUT when I switched to my bertagnis and then back to my diy panels I asked them how do they compare and all of them said the bertagnis were hands down better. I actually commend Ziggy on all his galliant efforts to finding the right/best design/sound for these panels and doing a lot of the experimentation. I also have read if I am not mistaken that Ziggy has passed? If so my condolences for his family and loved ones.

Hi Ubs

My reference speakers are double stacked large Advent Speakers, picking a winner between them is not so easy. One problem I am working on is if I run a frequency generator as an input and monitor the panels (one freq at a time) on an analyzer the panels will show the fundamental freq and sometimes multiple peaks above the fundamental. This shows up most often at the lower frequencies and at higher volumes. Recently I added a second coat of PVA the back of the panels, and this problem became worse and audible. The panel also became stiffer and I noticed a substantial loss of bass. I had to add more bass equalization which made the multiple peak problem worse. Since then I have begun to sand off this layer of PVA and the bass is now retuning and the multiple peak problem has gotten better.
I would be very curious to know how the Bertagni speakers react to inputting one freq at a time while monitoring on an analyzer. I am beginning to think I need much less or no PVA on the upper and lower portions of the panel and having two coats of PVA on the middle of the panel. Since I have begun sanding the panels I have noticed I need less equalization.

Fred

[rmeinke]

Re: DIY Flat Panel Speaker Love

My Panels are 20 inch by 36inc. 1inch thick EPS from lowes. Panels have been sanded on both sides with rounded corners with the 50/50 glue and water mixture on both sides as well. I made a rectangle shaped wooden frame using 1inchX2inch wood with a bar in the middle as well as one on the top corner to hold the exciters in place as I am using 2 exciters per speaker just like my bertagnis. I was going to build some 2 inch stands for them like my bertagnis but choose not too due to them not sounding to my satisfaction...They are positioned around 2ft. out from the back walls and about 8ft. apart.

Like I've said before I use my Bertagni speakers as my reference speakers to compare them too as I use the A and B speaker switching for direct comparison. I also believe from first hand experience that they do sound better with eq, even my bertagni speakers sound better with eq....but as of now my current diy panels do not come close to my bertagnis even with eq as the clarity is just not there. My next goal is to get some good quality EPS most likely the VH grade. I would also like to try some honeycomb material just like they use in the podium speakers.

Dont get me wrong I was not putting down ziggy in any way I was just stating one needs a DIRECT standard reference to compare it too or else everything can sound good like Korn bread mentioned. I did some comparison experiments using some of my family relatives as the judges. First I played my DIY panels and asked them how it sounded. With nothing to compare it too all of them said it sounded pretty good compared to what ever speakers they last remembered. BUT when I switched to my bertagnis and then back to my diy panels I asked them how do they compare and all of them said the bertagnis were hands down better. I actually commend Ziggy on all his galliant efforts to finding the right/best design/sound for these panels and doing a lot of the experimentation. I also have read if I am not mistaken that Ziggy has passed? If so my condolences for his family and loved ones.

I find KornBread and your comments about comparing to a "reference" a bit harsh, speculative and just as likely... inaccurate. Ziggy, for instance, had Maggies and other commercial flat panels over the years as well as a fairly sophisticated set of horn speakers he enjoyed along with his panels. He knew music and live performances well and, if I'm not mistaken, recorded orchestral performances professionally. I personally have a more positive view and find that most DIYers that frequent these forums are generally more experienced and educated in audio systems. Sure, there are some that use DIY to begin their audio journey but, typically, they are modest in there approach and understand that there is learning involved and the design process is not a straight line. It takes time and patience but this learning process is half the fun UBS.

You spent some time tweaking to get the best from your Bertagnis I know. This is tweaking to an existing speaker design that had countless weeks or months of tweaking, trial and error and certainly learning. Reading your posts, seemingly small tweaks improved Bertagnis yes? Now imagine the scenario where someone purchases some foam board, builds a wood frame and slaps a few exciters on the panel. As you might imagine, a tweaking process is needed to work through and complete the design. Seems reasonable does it not?

In the case of your panels, I am sure that there things that can be done to get more out of them. I currently do not have a solidly mounted panel to frame design so you, in some respects, are in uncharted waters for me. However outside of that, I'm sure there are a number of things we can do to improve them straight away.

A few thoughts:
* Believe you are using the DAEX30HESF-4? I haven't listened to that specific exciter yet (I do have a number of them on hand), but have time with it's little brother... the DAEX25FHE-4. As noted in past posts, the DAEX25FHE-4 seems to transfer more energy to the panel that results in higher levels of panel noise. It needs more suspension or a means of reducing the resonance and noise present on the panel. I have to think that the larger and more powerful DAEX25FHE-4 would have this same characteristic. I would consider using a smaller exciter for high frequencies; a smaller voice coil means better extension as the panel goes from DML mode to direct radiator mode (where the length of the frequency is the same or smaller than the size of the exciters voice coil). The output at that point is mainly generated within the exciter's vc cavity and immediate panel.
* If you read my recent posts over at AC, I have used the 3/4" low quality EPS and, like you, *think* I generally prefer the tone and clarity of it compared to 1" XPS. A higher quality EPS, in my opinion, is likely to sound better than XPS. EPS is less dense and has a resilient, spongy nature compared to XPS. It is also less damped... all of these are good qualities in favor of EPS. However the low quality EPS that we use needs some additional attention. My thinner EPS panels saturate VERY EASILY even with a single Ultra exciter. I chose the Ultra's on my test EPS because they tend to be better on light weight panels and transfer less noise to the panel. But even the Ultra completely dominate the EPS panel. A low powered, less expensive exciter will suffice on EPS unless the high density is used. Have to think that your panels are completely over driven by 2 DAEX30HESF-4's. Reading over one of your posts just now, I see you have only one coat the PVS treatment. 2 is a minimum but it is very likely that 3 would be better to both stiffen and damp the panel more.
* You didn't mention how the you isolated the exciters? I assume you have the second exciter on a smaller section of the panel somewhat isolated from the other exciter? How much mechanical isolation did you implement? More detail in this aspect of the design would be interesting. The Bertagnis use a simple passive crossover to reduce high frequency cancellation that occurs between the 2 exciters sharing the same panel. You may want to consider that.
* Do you have a means of measuring your panels? If you don't have a means of measuring, the Dayton Audio iMM-6 Calibrated Measurement Microphone is cheap and accurate. You will need the Audio Tools app to apply the calibration file and a good, high resolution RTA but these are also cheap and very easy to use. Until you have a way to measure and get some insight into your panels performance, its hard to tweak them. The EPS/Ultra combination had a HUGE hump from 200Hz to 1KHz. Until you know exactly what your EQing, it can be difficult getting the panels dialed in.

These are just a few things to consider if you are interested in DIY panels. Its really cool that you have the Bertagnis to compare to, and...model a panel after. I appreciate it and am in the process of stealing a few plays from his flat panel playbook (I have a list of things l like about his design and believe I understand why he did what he did). So we shall see just exactly how far we can go with some of Bertagni's design approaches. Either way... it sure should be fun!

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

I find KornBread and your comments about comparing to a "reference" a bit harsh, speculative and just as likely... inaccurate. Ziggy, for instance, had Maggies and other commercial flat panels over the years as well as a fairly sophisticated set of horn speakers he enjoyed along with his panels. He knew music and live performances well and, if I'm not mistaken, recorded orchestral performances professionally. I personally have a more positive view and find that most DIYers that frequent these forums are generally more experienced and educated in audio systems. Sure, there are some that use DIY to begin their audio journey but, typically, they are modest in there approach and understand that there is learning involved and the design process is not a straight line. It takes time and patience but this learning process is half the fun UBS.

You spent some time tweaking to get the best from your Bertagnis I know. This is tweaking to an existing speaker design that had countless weeks or months of tweaking, trial and error and certainly learning. Reading your posts, seemingly small tweaks improved Bertagnis yes? Now imagine the scenario where someone purchases some foam board, builds a wood frame and slaps a few exciters on the panel. As you might imagine, a tweaking process is needed to work through and complete the design. Seems reasonable does it not?

In the case of your panels, I am sure that there things that can be done to get more out of them. I currently do not have a solidly mounted panel to frame design so you, in some respects, are in uncharted waters for me. However outside of that, I'm sure there are a number of things we can do to improve them straight away.

A few thoughts:
* Believe you are using the DAEX30HESF-4? I haven't listened to that specific exciter yet (I do have a number of them on hand), but have time with it's little brother... the DAEX25FHE-4. As noted in past posts, the DAEX25FHE-4 seems to transfer more energy to the panel that results in higher levels of panel noise. It needs more suspension or a means of reducing the resonance and noise present on the panel. I have to think that the larger and more powerful DAEX25FHE-4 would have this same characteristic. I would consider using a smaller exciter for high frequencies; a smaller voice coil means better extension as the panel goes from DML mode to direct radiator mode (where the length of the frequency is the same or smaller than the size of the exciters voice coil). The output at that point is mainly generated within the exciter's vc cavity and immediate panel.
* If you read my recent posts over at AC, I have used the 3/4" low quality EPS and, like you, *think* I generally prefer the tone and clarity of it compared to 1" XPS. A higher quality EPS, in my opinion, is likely to sound better than XPS. EPS is less dense and has a resilient, spongy nature compared to XPS. It is also less damped... all of these are good qualities in favor of EPS. However the low quality EPS that we use needs some additional attention. My thinner EPS panels saturate VERY EASILY even with a single Ultra exciter. I chose the Ultra's on my test EPS because they tend to be better on light weight panels and transfer less noise to the panel. But even the Ultra completely dominate the EPS panel. A low powered, less expensive exciter will suffice on EPS unless the high density is used. Have to think that your panels are completely over driven by 2 DAEX30HESF-4's. Reading over one of your posts just now, I see you have only one coat the PVS treatment. 2 is a minimum but it is very likely that 3 would be better to both stiffen and damp the panel more.
* You didn't mention how the you isolated the exciters? I assume you have the second exciter on a smaller section of the panel somewhat isolated from the other exciter? How much mechanical isolation did you implement? More detail in this aspect of the design would be interesting. The Bertagnis use a simple passive crossover to reduce high frequency cancellation that occurs between the 2 exciters sharing the same panel. You may want to consider that.
* Do you have a means of measuring your panels? If you don't have a means of measuring, the Dayton Audio iMM-6 Calibrated Measurement Microphone is cheap and accurate. You will need the Audio Tools app to apply the calibration file and a good, high resolution RTA but these are also cheap and very easy to use. Until you have a way to measure and get some insight into your panels performance, its hard to tweak them. The EPS/Ultra combination had a HUGE hump from 200Hz to 1KHz. Until you know exactly what your EQing, it can be difficult getting the panels dialed in.

These are just a few things to consider if you are interested in DIY panels. Its really cool that you have the Bertagnis to compare to, and...model a panel after. I appreciate it and am in the process of stealing a few plays from his flat panel playbook (I have a list of things l like about his design and believe I understand why he did what he did). So we shall see just exactly how far we can go with some of Bertagni's design approaches. Either way... it sure should be fun!

It appears to me that you seem to be a little defensive about what Ive said about Ziggy but you have to keep in mind that this topic is not about Ziggy. Once again I am not trying to put ziggy down (far from it) or question his credibility or experience. My focus is on trying to build some speaker panels that can match or come close to my bertagnis speakers that I use as my reference standard. When I say my reference standard I do not mean my standard applies to everyone as it only applies to me the same way if you have YOUR reference standard it applies only to you and not to everyone else. But for DIRECT comparisons there needs to be some type of your own standard to compare it directly too, if not what are you comparing it too a distance sound memory?. If one shows you a picture and then asks you a 3 months later what you remembered on that picture in every detail, 99% of all people will not remember it UNLESS they have a Photographic memory and I believe in my opinion sound is similar in a way. Sound is also very subjective, so subjective that it can even vary on any given day be it weather changes or you just not being in a good mood , or listening to it for prolonged periods of time that your ears actually adjust to that sound etc and so on thats why a direct comparison to a reference standard of YOUR OWN is needed IMO.

When it comes to tweaking a (my bertagnis) existing speakers design one can only do so much unless you actually alter the existing speakers actual design. This is no different when purchasing any new speaker and trying to incorperate/adjust/tweak that speaker into your own (home) settings. When tweaking a speaker from scratch there is a lot more you can do/control since the whole speaker design process is in your hands to change/alter as one pleases hence why there is way more tweaking involved.

I agree there is probably a lot more things that could be done to get more out of them and one of my main goals in bettering the sound is to get a higher quality VH grade of EPS but untill then I will take some time off as I am pretty much burnt out and or a little low on cash as I have spent over $150.00 on materials and have not reached my desired sound yet.

I have many panels that I have experimented on using some type of coating from glue and water mixture to trying to use other materials to act as the skin of the panels like from all types of papers including wood fiber veeners to wrapping paper to baking parchment paper etc.... I have made some panels that have 3 coats of glue on one side while the other side has none some have 2 coats on one side while the other side has 1 coat or some panels with one side coated with glue mixture and the other side that has another type of material to act as the skin like wood fiber veener etc....so far I have not found the one that sounds to my satisfaction.

As for the isolation part I tried making indentions/craters similar to my bertagni designs but I used my dremmel which was not even nor accurate lol .....I need to buy and use a router to make it even but at $100 and up for a router I just dont have the money for it now. Yes I was considering a passive cross over but for now I will wait until I can get some high quality vh EPS.

No I dont have any type of measuring tool nor do I have the money for it right now. IMO the best measurments is my ears. If any panel I build can come close to the standard of my bertagni speakers then that is all the measurments I need for me to be satisfied.

I can sense my ole lady wanting to tell me> I TOLD YOU SO!!!! LOL

[rmeinke]

Re: DIY Flat Panel Speaker Love

Yeah, its fine UBS... I was being a little defensive indeed. The Walmart sound comment and the seemingly, ever changing panel material in the AC thread appeared like a jab at Ziggy and those involved in the thread over those many years. Initially, I didn't see a constructive message in the post but after rereading the post I do see it was in earnest and get what your position is. Of course that was not an accurate assessment as I think it is safe to assume that all involved had an existing system before embarking on their DIY panel journey.

In any event, I wanted to comment on that aspect tonight yet... later UBS..

Oh... before signing off... can you explain more about Bertagni's scalloped edges?? That was one aspect of the Bertagni's that I wanted more info on... I couldn't make out scallops in the panel edge itself. My feelings where that large scallops to the front of the panel combined with grooves all the way around the edges on the back of the panel, this should help to better terminate nodes at the edges/panel to solid frame transition. But one of the pics that I saw the scallops looked to be to the back of the panel????? Can you validate?

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Hi Ubs

My reference speakers are double stacked large Advent Speakers, picking a winner between them is not so easy. One problem I am working on is if I run a frequency generator as an input and monitor the panels (one freq at a time) on an analyzer the panels will show the fundamental freq and sometimes multiple peaks above the fundamental. This shows up most often at the lower frequencies and at higher volumes. Recently I added a second coat of PVA the back of the panels, and this problem became worse and audible. The panel also became stiffer and I noticed a substantial loss of bass. I had to add more bass equalization which made the multiple peak problem worse. Since then I have begun to sand off this layer of PVA and the bass is now retuning and the multiple peak problem has gotten better.
I would be very curious to know how the Bertagni speakers react to inputting one freq at a time while monitoring on an analyzer. I am beginning to think I need much less or no PVA on the upper and lower portions of the panel and having two coats of PVA on the middle of the panel. Since I have begun sanding the panels I have noticed I need less equalization.

Fred

Last time I heard any advents were in the 90's and the only advents I actually owned were the baby ones cant remember if they were 1s 2s or 3s?

I have experimented with using the pva glue water mixture and I have noticed the same thing about the untreated side having more bass and a little more clarity to my ears. Here is a experiment we can do together try putting some thin duct tape on the back side where the exciters reside and place the exciters directly on the duct tape and then tell me how they sound.

Sorry I dont have any analyzer or test equipment......I just use my ears lol

[Fshow]

Re: DIY Flat Panel Speaker Love

Last time I heard any advents were in the 90's and the only advents I actually owned were the baby ones cant remember if they were 1s 2s or 3s?

I have experimented with using the pva glue water mixture and I have noticed the same thing about the untreated side having more bass and a little more clarity to my ears. Here is a experiment we can do together try putting some thin duct tape on the back side where the exciters reside and place the exciters directly on the duct tape and then tell me how they sound.

Sorry I dont have any analyzer or test equipment......I just use my ears lol

Hi Ubs

That's ok about not having the tools, I was just curious.
About the duct tape. I have tried various tape on the panels several different times with always the same result which was negative.
I have the panels with the exciter side facing me, sounds better that way.

Thanks Fred

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hi Ubs

My reference speakers are double stacked large Advent Speakers, picking a winner between them is not so easy. One problem I am working on is if I run a frequency generator as an input and monitor the panels (one freq at a time) on an analyzer the panels will show the fundamental freq and sometimes multiple peaks above the fundamental. This shows up most often at the lower frequencies and at higher volumes. Recently I added a second coat of PVA the back of the panels, and this problem became worse and audible. The panel also became stiffer and I noticed a substantial loss of bass. I had to add more bass equalization which made the multiple peak problem worse. Since then I have begun to sand off this layer of PVA and the bass is now retuning and the multiple peak problem has gotten better.
I would be very curious to know how the Bertagni speakers react to inputting one freq at a time while monitoring on an analyzer. I am beginning to think I need much less or no PVA on the upper and lower portions of the panel and having two coats of PVA on the middle of the panel. Since I have begun sanding the panels I have noticed I need less equalization.

Fred

Hey Fred! This is very interesting. This behavior sounds very similar to what you find with light weight panels like XPS/EPS free mounted; most notable in low frequencies. Typically a fundamental peak and trough and sometimes a double but less pronounces peak and trough a bit higher in frequency.

Here are a few examples of different poly panels:


Does the response you are measuring similar? I wonder if the extra coat of PVA make the panel stiff enough to cause the panel AND frame structure to operate in DML mode?!?!

Really interested in this as the next panel/frames I'm building now are thin 1/4" x 1 1/4" pine. Sounds like I might be able to confirm this assumption before I route grooves along the panels edge to better isolate the panel from the frame.

Thanks for the post thread... good stuff!

[Fshow]

Re: DIY Flat Panel Speaker Love

Hey Fred! This is very interesting. This behavior sounds very similar to what you find with light weight panels like XPS/EPS free mounted; most notable in low frequencies. Typically a fundamental peak and trough and sometimes a double but less pronounces peak and trough a bit higher in frequency.

Here are a few examples of different poly panels:
[ATTACH=CONFIG]63272[/ATTACH]

Does the response you are measuring similar? I wonder if the extra coat of PVA make the panel stiff enough to cause the panel AND frame structure to operate in DML mode?!?!

Really interested in this as the next panel/frames I'm building now are thin 1/4" x 1 1/4" pine. Sounds like I might be able to confirm this assumption before I route grooves along the panels edge to better isolate the panel from the frame.

Thanks for the post thread... good stuff!

Hi Rich

I was hoping you read my last post and that I'd hear from you. As you read I put another coat of PVA on the backside, a pretty heavy coat. As you know after doing this you have to wait a long time for it to cure, but what I noticed was a large loss of low bass.
Yes, definitely these panel act in Dml and piston mode. The frames, panels and mounting act together especially at low frequencies. If you run the panel at a single low frequency signal and place your hand on the upper portion of the panel you will feel minimum vibration as opposed to the whole bottom of the panel which is vibrating like mad. The node appears to be large at lower frequencies, which makes sense. So I sanded the panels on the top portion and bottom portion and the bass is returning. One side benifits is I require no equalization on the middle frequencies now which before were always elevated.

Our panels are different because I am working on full range speaker and you are doing it the right way making it a two way. I am unclear on your frame. They are 1/4 X 1 1/4" pine but which way are you configuring the pine frame, is the frame a 1/4" wide and an 1 1/4" deep or the other way. When I tested for this distortion by looking at one frequency at a time it mostly showed up at lower frequencies so your design is much less susceptible to it.
Concerning your panel mounting or suspension I am not sure what you intend , but if the panel was infinitely large, it wouldn't matter if you had a frame or suspension, so taking it a bit farther if you had a frame solidly fixed to each other and the panel was infinitely large there also would be no issue. So at what size of panel and frame would the suspension be an issue?

Also another thing I noticed while testing was if I turned one speaker off and just ran one speaker at say 40 hz both panels would vibrate almost the same intensity. Evidently the resonant point of the panel or the room, or both. This is another reason or benifits of a two way panels.

With all these negative things going on with full range, the speakers still sound great and I am still continuing on.

Fred

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hi Rich

I was hoping you read my last post and that I'd hear from you. As you read I put another coat of PVA on the backside, a pretty heavy coat. As you know after doing this you have to wait a long time for it to cure, but what I noticed was a large loss of low bass.
Yes, definitely these panel act in Dml and piston mode. The frames, panels and mounting act together especially at low frequencies. If you run the panel at a single low frequency signal and place your hand on the upper portion of the panel you will feel minimum vibration as opposed to the whole bottom of the panel which is vibrating like mad. The node appears to be large at lower frequencies, which makes sense. So I sanded the panels on the top portion and bottom portion and the bass is returning. One side benifits is I require no equalization on the middle frequencies now which before were always elevated.

Our panels are different because I am working on full range speaker and you are doing it the right way making it a two way. I am unclear on your frame. They are 1/4 X 1 1/4" pine but which way are you configuring the pine frame, is the frame a 1/4" wide and an 1 1/4" deep or the other way. When I tested for this distortion by looking at one frequency at a time it mostly showed up at lower frequencies so your design is much less susceptible to it.
Concerning your panel mounting or suspension I am not sure what you intend , but if the panel was infinitely large, it wouldn't matter if you had a frame or suspension, so taking it a bit farther if you had a frame solidly fixed to each other and the panel was infinitely large there also would be no issue. So at what size of panel and frame would the suspension be an issue?

Also another thing I noticed while testing was if I turned one speaker off and just ran one speaker at say 40 hz both panels would vibrate almost the same intensity. Evidently the resonant point of the panel or the room, or both. This is another reason or benifits of a two way panels.

With all these negative things going on with full range, the speakers still sound great and I am still continuing on.

Fred

Hey! Well, there is no single right way as you have experienced yourself Fred. Your panels do play full-range and play full range very well my friend!

My framed panels... the frames will be glued edge wise so the 1/4" edge is facing to the front and back of the speaker. Or looking at the panels from the side, the frame is 1 1/4" thick. So the frame will be very light. I'm considering this a learning experience to see how a lightweight frame will interact with the panels.

The panels are 24" by 5'4" with 2 exciters per panel and isolated by a routed groove in the back of the panel. The plan is to test the panel and build from there as needed. First to route grooves around the edges of the panel close to the frame. If the panel and frame are still operating in DML mode together, I can add heavier wood frames which *should* remove and isolate the frame so it is not operating in DML mode with the panel.

On a side note, adding black ink to the PVA treatment makes it dry slowly and doesn't seem at hard. Not encouraging. :(

Interesting about the 40Hz coupling of the 2 panels! Have you played with toe-in? Test and check adjusting until the coupling is reduced/goes away? Then maybe play with distance to back wall if the toe in doesn't work? This is excellent learning (those panels are lightweight!) Fred but also speaks to how strong LF output is generated by your panels!!! Impressive!

note : I listen to my panels crossed 1 foot in front of the listening position. This is popular config. for open baffles.

Cheers!
Rich