DML woofer questions

[WrineX]

Originally Posted by rmeinke

No worries WrineX... you will have great fun with the Monacor exciters I an absolutely sure of it. Now you are really on to something... a honeycomb panel should be fun to play with and also bet you could create a very nice sounding (state of the art possibly??) panel at some point.

If I were to do something with a CNC, I wonder how a think ply (baltic birch) core and very thin wood skins on both sides would sound. Easy enough to make the honeycomb inside panel with a CNC but the skins on the outside are probably be the challenge?! Possibly a 1/32 inch thick veneer for the skins?!? I have not listened to thin ply yet, but other than the muted high freq. everyone else seems to like the wood panels.

I don't know for sure, but to me the XPS might be responsible for a bit of the muffled characteristic. I REALLY like XPS, and calling it "muffled" or "veiled" is harsh, but there is something to the presentation... the lack of presence... that bugs me the most about my panels.

But to be clear, I really do like the sound of these panels. They are addicting. After last nights listening session, I am nearly ready to ditch my Tang Band full-rangers in open baffles for these panels.

I am building a 2 panel full-range panel for my living room... that is a given. But also wondering about building a more narrow and tall panel with OB bass support for a smaller speaker that will sound just as good in a smaller space like my dedicated listening room.

Want panel love in both systems...

finally got the exciters, and tested one, the other one has a broken mounting plate


i am rather disapointed so far. its sound distorted muffled compressed. a small glass plate sounded best so far. i notce that the side where the exciter sits sounded best for the high fequency's, seems that the esciter itself radiates a big ammount of music themself. not what i wanted. i will play some more with it. but so far its not a winner.

[rmeinke]

Originally Posted by WrineX

finally got the exciters, and tested one, the other one has a broken mounting plate


i am rather disapointed so far. its sound distorted muffled compressed. a small glass plate sounded best so far. i notce that the side where the exciter sits sounded best for the high fequency's, seems that the esciter itself radiates a big ammount of music themself. not what i wanted. i will play some more with it. but so far its not a winner.

Hello WrineX,
Something definitely is not right here with the panels.

I don't know what Monacor exciters you have but I did have a bad experience with the Visaton's that have a square plastic base that attaches to the panel... it was a waste and plucked them from the panel before they were even broken in. I hope that its not the exciters. That would be a major bummer after waiting for them to arrive.

Outside of that, I don't know how long you have listened. But even after playing them with a 40Hz signal over night and into the next day the best Dayton "Thruster" took a few hours to break in once mounted on the panels. I had a lot of panel "self-noise" for 4-5 hours I'd say before it started to clean up and become listenable. It still toke some 20 hours I would say before they sounded totally "clean". The cheaper Dayton's that I initially used didn't sound good for about 30 hours and probably didn't break in fully until 60-70 hours or so.

Next would be the panel material. I used cheap EPS first as I was told even the cheap stuff sounded similar but I did not find that to be true and ditched them immediately. I didn't even build a second panel to have stereo and went out right away and got the 24inx24in 1 inch thick XPS panel and it sounded MUCH better right from the beginning... even with the self-noise. Any details on the panel material and its treatment might help.

Other than these 2 aspects the only other thing I can say that would impact the sound quality is how they are mounting or set free standing. Any details there might uncover up something but it still seems like a exciter/panel issue or just plain break in time.

Hard to go back to the beginning of my panel journey but I do remember that too could not believe what others were saying when I first started listening to them... I did not hear the lovely panel sound that others described. Ohh, as I type... I remembered one more detail....tell me about the room!?

Nearly forgot... I was close to giving up on them when I decided to remove them from my small listening room and took them down into my living room which is much larger and I'm able to pull them out into the room 4+ feet. This is when I started to hear more enjoyable music. My panels remain in the large living room propped up on chairs. I don't think that this is your issue as this doesn't make them play as you describe but I did get a fairly large boost in performance as I moved them out into the room. Wanted to state that.

1 more thought and general impression and NOT related but wanted to state for the record either way. I have found, at least with the Thruster exciters, that they seem to take a good 20-30 minutes to "warm up" before I start to hear panel magic. Very similar to my old Quicksilver mono-blocks. Then, and now with the panels, I would often stay up late listening to music and found myself in almost a meditated state where I could hear even the smallest nuances in music.. its incredible enjoyable. However when after I wake up in the morning, wanting to continue that enjoyable listening experience, and turn on my system it sounds flat and lacking and largely disappointing. I would have to think its the steel spider Dayton exciters and that the heat makes the metal more flexible and must go through a critical warm up period before they begin to sound good. Again... not related specifically and very likely not a not a cause of your problems but throwing it out there as something I've experienced the last few weekends.

Anyway, let us know about your build details. Surely something is wrong if you are hearing muffled and distorted sound from the panels there are issues that we need to work through.

[WrineX]

Ok well the exciters are the Monacor AR 30 weather proof, so its all in a sort of plastic housing, there is a screw terminal where a plate screws in to attach to a panel with screws. (or tape) the spider of these things are insanely rigid. i can hardly push them in. but when connected to the amp they do vribrite pretty hard, not like high excusrion but brute force or something i dont know.

AR-30




Panels materials different sizes (although all in range of 13 x 10 inch or so). Main concern was highs, i dont mind not having BASS since i dont expect one exciter for each panel to deliver that (also not on this size panels). i first want good mid and highs before i decide to move on.

something that all panels had was, the exciter side had more enjoyable treble then the other side


materials used

XPS 2 inch thick (5cm) , sounded loud but dull. best highs when positioned near edges or at least out of the middle horizontal and vertically. ringing in low mid region as well

acrylic 2 mm thick small piece. ok but still not enough highs for my taste and some ringing like oempfff in the mid low end

Glass 2 mm thick sounded pretty good but also ringing in mids and again not enough high end and to low spl

Polysterene Louvre and the small acrylic panel taped to each other, i think it sounded the best even though i taped the acryl on the louvre with double sided tape.

(the louvre panels is like a raster grid, but in squares. i might need to sandwich with 2 acrylic plates and use hard glue instead of the softer tape.
could create pretty much low for the size, and high where really critical with placing of the exciter, still i founded i need a bit more top end. less ringing then the other meterials

tried wood and related objects but all sounded crap.

[rmeinke]

Originally Posted by WrineX

Ok well the exciters are the Monacor AR 30 weather proof, so its all in a sort of plastic housing, there is a screw terminal where a plate screws in to attach to a panel with screws. (or tape) the spider of these things are insanely rigid. i can hardly push them in. but when connected to the amp they do vribrite pretty hard, not like high excusrion but brute force or something i dont know.

AR-30

Panels materials different sizes (although all in range of 13 x 10 inch or so). Main concern was highs, i dont mind not having BASS since i dont expect one exciter for each panel to deliver that (also not on this size panels). i first want good mid and highs before i decide to move on.

something that all panels had was, the exciter side had more enjoyable treble then the other side

materials used

XPS 2 inch thick (5cm) , sounded loud but dull. best highs when positioned near edges or at least out of the middle horizontal and vertically. ringing in low mid region as well

acrylic 2 mm thick small piece. ok but still not enough highs for my taste and some ringing like oempfff in the mid low end

Glass 2 mm thick sounded pretty good but also ringing in mids and again not enough high end and to low spl

Polysterene Louvre and the small acrylic panel taped to each other, i think it sounded the best even though i taped the acryl on the louvre with double sided tape.

(the louvre panels is like a raster grid, but in squares. i might need to sandwich with 2 acrylic plates and use hard glue instead of the softer tape.

could create pretty much low for the size, and high where really critical with placing of the exciter, still i founded i need a bit more top end. less ringing then the other meterials

tried wood and related objects but all sounded crap.

This is purely speculation but given what I heard from the Visaton exciter I imagine that is mainly exciter related and what is responsible for much of the poor sound quality. It appears to have a larger than normal plastic "boot" like the Visaton. the Visaton measured fine but they sounded dreadful to me... even compared to the cheap $8 Dayton exciter. The Visaton also had a very still spider. I believe this results in more panel noise and the reason why you are hearing so much panel noise and muffled sound. Even going from the Dayton Thruster exciter to the Ultra (lower Fs and more compliant spider) the panels were notably quieter (the first thing that hit me within seconds of pressing play... not even broke in I noticed this immediately). I explained over at the PE forum as like having a better signal to noise ratio.... best way to explain it. A stiff spider appears to result in a fuzzy sounding panel... but I reserve the right to change my mind as the Thruster model sounds very good! Possibly some combination of spider stiffness to magnet strength?!?


Not sure about the design decisions that lead to the use of these plastic plates. Even the NXT modeling software shows HF impact as you move from a small 25mm voice coil to a 32mm vc. How a larger large plastic mounting plate does to the performance... as we now know... destroys all panel magic. Further, the extremely stiff spider likely contributes to the poor sound as well... especially on light-weight materials like XPS. But if you say these exciters also sound horrible on ply (which I thought was the intended material or like material) I really wonder what the target panel material was? have to wonder if the designers of these exciters have actually listened to them?!? maybe they are shooting for high power-handling and durability. Can NOT be fidelity... this is for certain. I'm amazed the differences in how each exciter sounds. Possibly more of a difference than going from a cheap woofer to a ScanSpeak quality driver. Not what I would have expected honestly.

To panel material. With such small panels I would try 1/2inch to 3/4 inch XPS or high density EPS sanded and treated. Really need to get the "skin" sanded off or they sound like... well, plastic. The 1:1 water to glue wonder treatment is needed to damp the panel... they need a few days to cure but I continue to hear improvement over 1 weeks time before they seem to stabilize. Also, round the corners and break the edges as well and get the Ultra or Thruster Dayton exciters and the world of delicious panel sound will begin to fill your listening room.

Sorry to hear about the poor results... majorly sucks man.

[WrineX]

well looks like i must keep my eyes open for some thusters then i hope they can be bought in europe


im gone take a look . Thx for all the information!


what do you say Ultra or thruster . wich one is better , especially in the high frequency ? its funny they are 24 euro in europe compared to 16 dollar in US almost 2 as expensive. the rats



the monacor is a bit like the dayton http://www.intertechnik.nl/Shop/Luid...nl,7052,147899

[rmeinke]

WrineX ... you have a PM

[mexican]

Hi folks, my english is bad, I do not use exciters, I use speakers to drive membranes for bass with good (I think) results. (ok it is a exciter)

I have a little prototype (10x5 in) playing (on my side) Eva Cassidy "What a wonderful world" right now, I never heard that bass so clearly in a speaker that size.


I want to share a video of its sound, I have an Iphone 5, It is a good reference?

Impresive posts!

[rmeinke]

Hey Mexican,
Would love to see a video! Some measurements would be awesome too! I have used an RTA on my iPhone 5 with pretty decent results. "RTA Lite" is good for a free app but for $5 the "Audio RTA" is excellent with 1/12 octave bands for better resolution.

Curious how big the voice coil is and how its mounted to the panel. With such a small panel it would be interesting to see if it is operating as a DML or semi pistonic?!? But either way, cool that it sounds really good. :-)

Have you visited the AudioCircles form... "Open Baffle" circle and thread "NXT.......rubbish??....THINK AGAIN!" ?? Seems to be the home for DML magic panels.

[mexican]

OMG rmeinke NXT.......rubbish??....THINK AGAIN! is not a Thread is an encyclopedia !!! ...poor Zyggy!! Rest in peace
hanks for the hint, I have to go translating and go slow, there is much homework to do for me.

This picture is from my exciters

radiator.jpg

I put the analizer in my daughters iphone
I live next to a populated street so I have to make this test at 3 am and isolate noise from the computer.
Can I use pink noise?
Can I use equalizer?
The ideal distance?
Sorry! too much questions.

And now a hint from me: The panel do not have to be anchored firmly, if it bends got to have freedom to shorten its distances. linked or roller
https://ecourses.ou.edu/cgi-bin/eboo....1&page=theory

Thanks
BTW I think is semi pistonic

[mexican]

3x4 in. Flat panel

Some experiments creating graphics, do not take them seriously I do not know if in the correct protocol.
mex1.jpg sweep with and without eq in bass at 1 inch
mex2.jpg sweep diferent volumes at 1 inch
mex3.jpg pink noise from 1 inch to 30 inchs