ESL and Dipole hybrid system.

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi all,
I just made a very rough experiment, I don't know if there is a system like this before.
I like the sound from ESL system, but it's beyond my budget, so maybe I can DIY it, but again, it seems not easy to build and the transformer price is high too.
Then I remember the dipole system is very similar with ESL, both is open baffle system, so why not use ordinary driver to drive diaphragm and the experiment began:
I use 6" driver that I used with open baffle system but with 40x60cm baffle it rolled off too early (started from 200Hz), it's because small size baffle and small size cone area.
I made 40x60cm diaphragm frame and then I streched out very thin plastic wrap as a membrane on it, behind this membrane I glued 35x55cm 1" thick solid styrofoam panel ( it's very rigid but lightweight).
The styroform can move back and forth around 6mm, it is close to xmax of the driver.
Next step was fixed out Diaphragm frame with the driver, so it became one part, then using some spacer (styroform block) I fixed out styroform panel to the driver's cone, that's all!
Hearing result, the first thing I notice, there is more bass came out, more balance sound not just mid and high only, remember I used the same baffle size as dipole system.
Because it is very rough experiment, it needs expert to do more test with a good equipment.

Chris.
 

Attachments

  • hybrid.gif
    hybrid.gif
    10.1 KB · Views: 672
Haha little misleading title, but yes this sounds like a great experiment.

I have often thought of doing something like this. Except maybe like a line of drivers that all drive a single membrane. This way you get super surface area, plus only one emitting surface.

A fun, yet cheap experiment!
 
Interesting.

This is an interesting experiment.
The performance might be poorer in HF than the normal driver.
Since the radiating surface has mass , it might not be able to move fast enough as the frequencies go up. In addition coupling of the flat panel to the cone could also eat up some of the HF.
Do you get as much HF as you do with the normal cone?
It might also sound smoother than the cone as it could roll off any cone break up effects of the original cone. For LF it probably still behaves just like a normal speaker with more mass. So the resonance will go down and Qts will probably go up. So you could get slightly deeper or more bass.

If you want to make something that is closer to an ESL ( a planar speaker !) , you should check the forum for flat speakers. I saw something long ago. It was a small speaker ( 3 or 4 inches) facing upwards and covered on top with a round plate with a small hole in it. This hole opened out into the space between two films of PVC held apart by two vertical posts. The top end was closed. So the cone movement caused air to pump in and out through the hole into the space between the two films and caused them to vibrate ( outward) like a BIPOLE driver. Sound was considered to be good . Apparently it has lots of limitations and so is not commercially seen . The picture showed a device used as a computer speaker with decent sound.
It might do what you want it to. You could agument the bass with an external driver.
Have fun !
 
That's a very cool speaker you came out with :cool: In the late '80's there was a Sumo Aria speaker which later became the Meitner speaker. It had a magnetic structure just like a normal driver but instead of a cone it used a large sheet of stretched Mylar. Sound was quite good actually but there were some resonances which they tried to control by gluing some felt strips on the mylar membrane. Your idea of using the styrofoam is a good one do keep us updated on how it sounds and btw is there any change in the loudness/efficiency of the speaker?
 
Hi all,
thank's for positive comment.

Hybrid,
any better name for it?
Multi driver setup, I though of that too, however I wonder using multi driver will cause non uniform movement of the membrane, because each driver movement not 100% similar, or we can tolerate it because the different is too small?

Ashok,
I didn't hear HF lost, because maybe I use mid driver not fullrange.
The benefit is I hear more bass for the same baffle size than dipole system, with dipole system I need around 80X120cm size of the baffle for the same bass output.

BTW,
yes, I lost a fraction of efficiency compare with box system, but with dipole system it's almost the same volume.

Guys, I can't give more than just subjective hearing report, but what I like with this setup is: it's dipole system with all the good thing of it but with smaller baffle size I get more bass!
It's beyond my capability about the theory and formulas behind this setup, it will be a great help if somebody can explain the +/- of it and make a deep measurement, so we all can learn more.

thankyou,

Chris.
 
christophorus said:
Hi BTW,
Thank's for the link, although it's rather different, they use point source system to drive the membrane.
How's the sound of that speaker? do you own it?

Chris.

Hi Chris,

A friend of mine who used to run a audio shop, brought in the Meitner spk and I spent a lot of time listening to them. I'm actually very impressed with this speaker very natural sounding indeed. Too bad it never received the commercial success it should have.
 
Uhhhh.......

i guess i want to ask why you have choosen to do this in this manner....

One of the big reasons ESLs sound good, and one of the reasons people buy them is becuase thier diaphram is weightless enabiling it more agility then a normal cone speaker....

Why on earth would you then use a cone speaker to drive a membrane to get the ESL sound? The membrane will now only sound as good as the driver.

Its like: I can't afford to fix my awsome Jag XKE engine, but instead of paying the money to fix it, I'll through a ford taurus engine in the trunk and have it push the drivetrain.

Save up the money, buy the transformers.

Brian
 
Hi Charles,
Where did you get the image? Is there any explanation or article or some measurement test for it?

Hi VictorG,
you wrong! at least I can hear more LF than normal baffle with normal driver.
Do you know how much a good transformer cost?
Do you know how difficult to DIY real ESL?

Hi BTW,
when I wrote this thread, I have no idea what should I name it, so I put the title from what I know so far, too bad I can't change the thread name, or maybe I open a new thread with that name and link to this thread?

Actually, it's very easy DIY to try, I use it for 2 week's now, the LF is extended and mid freq attenuated slighly, with dome tweeter, the sound look's balance without any complicated active XO.

Chris.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.