S16 - Constant Directivity Dipoles

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Hi Orang Kota...

Never glue something !!! In case you get badly centered coil, the driver will be hard to fix up. For me the solution has been to make a front plate, exactly like in any dome tweeter. It has to be well done, but it's not very difficult. The most delicate is the four holes for the screws that have to match the holes of the driver.

In my Hutan universe, the evidence was to make this in wood (kayu uru, perfect !). It's router friendly (more than plastic or metal), the thickness allows rounded edges, the precise adjustment is much easier than with metal, and no metal parts (if iron) will dive in the magnetic gap.

I have been using an adhesive that never gets dry (Dow Corning LDC7091) to secure the coils planes in case of vibration. It also makes the adjustment easier (check with a sinus tone that the coil is not touching something when you close the driver).

The last problem is the cables connexion that have to be secured. And don't forget that this kind of magnet attracts any screw or tool from far and dent the membrane.

Have fun !
 
So I started thinking about Waveguides + dipole midranges an it looks like you beat me to it.

I was wondering if you ever matched your waveguide and mid to a sealed or ported sub for low end instead of the dipole you are using now. Sort of a waveguide (pro audio/gedlee) , dipole mid (linkwitz), sealed or ported sub bass (watt/FAST) mashup. I have a feeling it's a wining combination. The two concerns I would have would be that 1) the sealed sub will not mate well with the rest of the system, 2) The waveguide will not mate well due to it's monopole response.

Your measurements seem to look good when you were just using the waveguide and not a second tweeter, but you said that it sounded off. Was this something that sounded very wrong or something that you just weren't accustomed to? What if you used matching compression drivers and waveguides and mounted them back to back? Is it worth going to that level?
 
Your measurements seem to look good when you were just using the waveguide and not a second tweeter, but you said that it sounded off. Was this something that sounded very wrong or something that you just weren't accustomed to? What if you used matching compression drivers and waveguides and mounted them back to back? Is it worth going to that level?

Hello, yes it sounded off because there was no rear radiation. For a long time I tried to get myself accustomed to the sound, but they simply sounded wrong after sometimes.

Logically the way to fix this is to add rear firing waveguide+CD, but it will be expensive and physically ugly approach.

My last compromise was to use small Monacor waveguide mated with Vifa XT25. The polar response is not as great as large waveguides, but the rear can be easily implemented. Check out the pics on my blog.
 
Hi guys

Can I make a different suggestion? Have you considered the Beyma TPL150-H? It has a horn on the front, and then you just remove the rear cover from the driver. This is less destructive than with a compression driver, and on a open baffle you will have the rear radiation you seek for free. There are threads discussing this on the forum. Just a thought.

Enjoy,
Deon
 
I took a look at your Monacor waveguide mated with Vifa XT25 setup. It seems to me that if you are willing to get that far, you might as well try an addition waveguide+compression driver. To be honest, it's on the back, you really don't see it and you are already 90% of the way there with your monacor + XT25.

did you take time to do directivity tests with the speakers facing away to see if you are getting a true figure 8 response? It looks like the rear waveguide would have a negative effect on your response where it is mounted. I am not sure how much it matters in the real world but Linkwitz seems to make it sound like it is important.

Looks like a great build, wish I could hear it.
 
A release of this design, hence I call R16 is being commissioned.

Some unfortunate work situation made me unable to do it by hand, so I had to 'outsource' it. It's pretty hard to explain the goal to a furniture maker so I took out my S19 and ask for 'something like this' minus the top speakers ...!

Some pictures and more to follow :). The subs will be W-Frame dipoles.

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