Hi,
my name is Norbert, I'am from Germany, so please forgive me my terrible englisch . Month ago I started reading in here and today I will present the 'JASD' (Just A simple Dipolspeaker).
2 years ago I started with this glasswall und a SALABERT PHY21 which is well known (I think) in this forum. The dipol itself has a flat frequenz response up from 80Hz wenn it is positioned 40-50cm from the backwall of the listening room.
I had 2 problems with the PHY. First, in the high frequency range from approx. 9-10khz the curve is falling down (that means: using a supertweeter) and second: there is a need for an additional subwoofer. But my wish was/is running a fullrange system (55-16000Hz) with only 1 unit.
Weeks ago I found an italien manufactored driver the 'CIARE CH250' http://www.ciare.com/pdf/catalogo/CH250.pdf
which has an Qts=1.36 at 65Hz und this dip fills the hole at 50-80Hz.
Not only in relation of the price (app. 42.00 US$) its sounds wonderfull and I have a lot of fun with this dipole.
my name is Norbert, I'am from Germany, so please forgive me my terrible englisch . Month ago I started reading in here and today I will present the 'JASD' (Just A simple Dipolspeaker).
2 years ago I started with this glasswall und a SALABERT PHY21 which is well known (I think) in this forum. The dipol itself has a flat frequenz response up from 80Hz wenn it is positioned 40-50cm from the backwall of the listening room.
I had 2 problems with the PHY. First, in the high frequency range from approx. 9-10khz the curve is falling down (that means: using a supertweeter) and second: there is a need for an additional subwoofer. But my wish was/is running a fullrange system (55-16000Hz) with only 1 unit.
Weeks ago I found an italien manufactored driver the 'CIARE CH250' http://www.ciare.com/pdf/catalogo/CH250.pdf
which has an Qts=1.36 at 65Hz und this dip fills the hole at 50-80Hz.
Not only in relation of the price (app. 42.00 US$) its sounds wonderfull and I have a lot of fun with this dipole.
An externally hosted image should be here but it was not working when we last tested it.
Hi Norbert, that's a very nice speaker that you have there and let me say straight away that I am a big fan of keeping things as simple as possible.
I am currently using modified Goodmans 201's full-range drivers in open baffles (with piezo super-tweeters) but am looking for something more in the 40-90Hz region. Those Ciare drivers seem like a dream -come-true!
Do you find that you don't need a supertweeter with the Ciare drivers?
I am currently using modified Goodmans 201's full-range drivers in open baffles (with piezo super-tweeters) but am looking for something more in the 40-90Hz region. Those Ciare drivers seem like a dream -come-true!
Do you find that you don't need a supertweeter with the Ciare drivers?
With the low cost of the driver, even the price of the glass baffles doesn't make this an expensive speaker. If they sound anything like mine, this has to be the best sound-per pound speaker going!
Add a Gainclone and something like a modified CD723 and you have a seriously good system for 450UKP. DIY rules.
Add a Gainclone and something like a modified CD723 and you have a seriously good system for 450UKP. DIY rules.
If you want to try it Bricolo, you couldn't do any worse than try these Ciare drivers. Use a piece of ply/MDF for the baffle (brace it though) and you can see if you like it. You can see what sort of size from Norbert's picture.
Try different speaker positions etc. If you do like it (and I can't believe that you won't) just get your glass baffles.
Well, without starting at the beginning and writing a book on the subject of speaker building 
...
When you have an open baffle, the rear waves from the speaker cone can wrap around the baffle and mix with those from the front. What this means is that the rear waves and front ones which are 180 degrees opposite phase will cancel each other out. This mainly affects the bass frequencies so you loose bass. (Get the idea of having a box now?)
Obviously, the smaller the baffle, the more cancelleation you get, hence the largish baffles that you see people using.
There are other effects too like beaming where the 'smaller' high-frequency waves are reinforced when they bounce of the baffle. So the larger the baffle, the more they bounce (or beam).
So you need a larger baffle for bass and a smaller one for high frequencies and just like any thing else to do with speaker building you have to make a compromise.
Now don't let you put this off. Read Norbert's post again. With the right driver and baffle size you can get very good results. And when you hear open baffles you will realise why we put up with the baffle size and other problems.
A good baffle size to start off with if you want to experiment is 1220mm by 610mm. Norbert's look slightly wider than that to me.
And if you type 'open baffle' into the diyAudio search facility, you will find plenty of other threads to answer your questions.
...When you have an open baffle, the rear waves from the speaker cone can wrap around the baffle and mix with those from the front. What this means is that the rear waves and front ones which are 180 degrees opposite phase will cancel each other out. This mainly affects the bass frequencies so you loose bass. (Get the idea of having a box now?)
Obviously, the smaller the baffle, the more cancelleation you get, hence the largish baffles that you see people using.
There are other effects too like beaming where the 'smaller' high-frequency waves are reinforced when they bounce of the baffle. So the larger the baffle, the more they bounce (or beam).
So you need a larger baffle for bass and a smaller one for high frequencies and just like any thing else to do with speaker building you have to make a compromise.
Now don't let you put this off. Read Norbert's post again. With the right driver and baffle size you can get very good results. And when you hear open baffles you will realise why we put up with the baffle size and other problems.
A good baffle size to start off with if you want to experiment is 1220mm by 610mm. Norbert's look slightly wider than that to me.
And if you type 'open baffle' into the diyAudio search facility, you will find plenty of other threads to answer your questions.
Bricolo said:I think I'll try some open bafles made of glass, too
I know nothing about IB design, where can I start with? Do you guys have good links?
Some useful dipole speaker sites:
Linkwitz Lab
Steve Dodd's dipole designs
Big Baffle Development Page
DIY Subwoofer Page (dipole section)
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