A Study of DMLs as a Full Range Speaker

Burntcoil.
Hi ,the first picture is of the ply panel,the second pic is the 3mm hardboard at about 1m.
The low end goes all the way down to 20hz on both panels ,with the upper peak higher on the hardboard ?
No weights or paper used,just the basic panel.
Might measure the 3x2ft and do a recording ,I can play louder as the panel is glued as well as screwed together solidly.

100ohms.
Can't say I'm not a little confused,it could be the drink I had earlier,you glued a ply panel on the cardboard panel and drilled 5mm holes around the exciter and stuck cardboard rings near the top corners .
It's all part of the learning curve.
Steve

Hi Steve
how is your impression with your ply-/hardboard panel at the low end? Have you switched your sub on and off while listening to music and is the sub not any more required?

Sorry for confusing. Will check out some more strange fruits;-)

By the way, the bass is booming on the corrugate cb panel. Together with the honeycomb cb on the other chanel, the sound is better balanced for me but not yet ready for a presentation.
Eric
 
100ohms.
I suppose it depends on how much of a bass head you are,if you like trousers flapping bass,then a separate LF driver is essential.
If you mainly listen to classical music or jazz then the panel is fine,I can't really push it to the limits because the panels are not properly glued together ,they are far too big for my room,and were always intended to convert in to room treatment panels, when filled with damping.
There reason I did the recording was so that you could hear the bass response over headphones,I did adjust the LF with audacity to make up for the short Cummings of the microphone,but only to match what I was hearing in the room,no more.
I personally would always use a separate LF driver for all of my panels,to save the exciter and panel from large movement.
On some CD's there is excessive amounts of LF that can catch you out ,and start the exciter banging about on the back of the panel.
I might do a recording of the 3x2ft panels without LF units to see how they compare, although one of the panels has only two sides Framed.
Hopefully I should be able to turn up the volume a lot more,as they are properly glued together.
Steve
 
Hi there,
I didn't read the whole thread, my question is: Has anyone tried a push-pull arrangement of the drivers? Means one driver on the backside while a oposite polarity driver on the frontside?
Also, I wonder if there would be any positive effect of having a stiff adapter plate, e.g. CFK plate, where the drivers are mounted on that couples to the regular panel (e.g. XPS)?

Another one: I didn't find any information about multi-layer Balsa plates (e.g. Google Ubersetzer)
Thanks, Markus
Markus
 
Hi Markus,
My thoughts on doing the push pull is not that effective because in that configuration one covers up the high frequency emitting area by having the exciters blocking each other.
If you listen to the panels most of the high frequency is emitted right where the exciter is.
I have found by placing a passive radiator right over the exciter on the front surface gives the best response. This radiator can be a hemisphere or a cone of thin metal foil.

Cheers,
Steve
 
audio

hi this recording was 8.5mb but would not upload, so cut to 6.3mb ,i was a little surprised at the loss of detail that converting to mp4 has on the fine detail ,like the rain beads individually falling.
it will be interesting to hear what it sounds like once it is uploaded.
steve
 

Attachments

  • codona3 cut mp4.mp4
    6.3 MB
The microphone was placed between the two EPS panels ,with the panels turned towards the microphone,the volume was turned up very high,so that the trumpet was quite painful at 3m where I was sitting.
When setting up and testing the recording,i was trying to demonstrate the shear unrestrained power of the trumpet , unfortunately My wife poked her head round the door to call me for garden duties,and was only a foot or two away from the left panel when the trumpet blasted out,she let out a painful yell , eye's and mouth wide open!!
I had to laugh out loud as her face was a picture,total shock!!
The metallic sounds are also awesome,even in the recording,which hopefully shows up well.
Because of the way it is recorded I would recommend headphones for the best monitoring of the sound.
Hope you liked it.
Steve
 
Annoyingly after listening to this recording many times , I've come to the conclusion that the recording gives no impression of the volume I was playing the music.
Maybe I should have clapped and shouted like the guy in the tech ingredients video ,to give the volume a reference?
Trying to record good sounding music in an ordinary room isn't easy, minimising room responses and reverberations while trying to record atmosphere and depth!!
But this is the best I can do with what I have.
Steve
 
I presume you are not making a dummy head for binaural recording?
The old stereo microphone I use surprising sounds very good to me , except for the excessive noise.
Even if I built my own mic , which would be fun, I would still have to find a way of recording to my computer,which would cost more money.
And as it would only be used for posting on this site,I can't justify the time , effort ,and money, I'm afraid it is another distraction from panels.
I'm not even sure if posting recording is of any help or not,but thought it would show that DML works,and works well, whether large or small, heavy or light,they just have different characteristics,but with a similar sound.
Not sure if I'll post any more recordings as I've covered most of the materials I like.
At the moment I'm more interested in smaller panels,that aren't really relevant to this full range site,even though the XO point is only a few hundred HZ difference from what I would XO my large panels.
Steve
 
I presume you are not making a dummy head for binaural recording?
The old stereo microphone I use surprising sounds very good to me , except for the excessive noise.
Even if I built my own mic , which would be fun, I would still have to find a way of recording to my computer,which would cost more money.
And as it would only be used for posting on this site,I can't justify the time , effort ,and money, I'm afraid it is another distraction from panels.
I'm not even sure if posting recording is of any help or not,but thought it would show that DML works,and works well, whether large or small, heavy or light,they just have different characteristics,but with a similar sound.
Not sure if I'll post any more recordings as I've covered most of the materials I like.
At the moment I'm more interested in smaller panels,that aren't really relevant to this full range site,even though the XO point is only a few hundred HZ difference from what I would XO my large panels.
Steve
Hi Steve
Your thoughts about recording the DML-impressions I do appreciate a lot and the published audio-files are very useful for me. I think about a 4- / 5-track record with a stereo-mic for the room and 2 / 3 (1 for sub) mics close to the speakers could give a different result. With the mixdown to 2 ch you may get closer to the sound, you experience.
I wonder, if there are ways with smaller panels and being still in this fullrange site. Mr Heil e.g did a tweeter which goes very low for its size. Is it because the diaphragm is folded?
Eric
 
Hi all, lurking this topic for a very long time and slowly getting a idea of the way I want to go.
I have 1 small question.
Does anybody have some experience with Aluminium Dibond with a polyethyleen core (solid) which is used by all those photo print companies?
Would love to learn about some experiences.

Kr

Arjan
 
So I finally got my materials. I got the cheap EPS foam from Home Depot and I got the Dayton Audio DAEX32U-4 Ultra 32mm Exciters. I just need to cut the foam to size and put the glue/water mixture on. I plan to test it out in phases just to see the differences. First the EPS foam as is, then cut to size, then with the glue mixture applied, then I’ll probably EnABL them to see if it does anything at all. At that point not sure we’ll see what that gets me. I still need to download a good freq program so I can post on here. Haven’t decided how I’m going to mount, the exciters are heavier than I thought so I might have to figure out a way to implement a support spline depending how well the exciter can hold itself to the foam. Has anyone that’s used foam noticed any benefit on how they attached or supported the exciter? I’ve read and seen about the frames, but right now I’m not quite at the full diy wood cutting, glueing etc phase. I don’t want to go all out till I figure what material I like best. If the foam pleases enough I’ll stop with the foam, but I have a feeling due to plywood here being a fav I’ll end up trying it out as well.