First time OB builder

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Already started to formulate some ideas of suspension. The idea of using some clear acrylic sheet appeals to me, even though it can be expensive in thicker sizes, I think it would look kind of cool if the drivers looked like they were suspended in mid air.

Am initally thinking springs to hold them in place but a piece of threaded rod would probably work just as well.
 

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No I was actually refering to the vertical spacing. As you can see in my current speakers there is a gap between the mid and the woofers. Was wondering if that was still required in OB /NB.

Requirement here is the same as with any speaker, ideally within 1/4 wl.

Attached is a pic of my dipoles as they are currently, sorry for the quality it's a phone shot.
 

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Thanks for that Nate much appreciated. Its good to see the ideas of others and draw some inspiration.Last night the neighbours car alarm went off three times at 1.30am and then I couldn't sleep. While trying to get back to sleep an idea came to me... For the last few days I have been kicking around the idea of using an acrylic holder to mount the drivers, but hadn't really finalise a method of holding the holder in place. Well last night the idea of using bicycle spokes popped into my head. The idea is drill some small hole in the acrylic plate near the edge and push the spoke through. If I could get a die the same as the thread they put on the rim end I could make them whatever length I want.
 
On the weekend I was moving the tweet/mid crossover point up and down the range (never lower than 1600) and every time I keep coming back to the factory recommended 1600Hz with 4th order L-R crossover.

No 3 x 2 for L-C-R, and 1 in each of 4 rears, or 2 x 2 if I only make 2 rears.

Not sure how loud you listen and I know CTC suffers, but I do not like the Raal below 2KHz. I don't even use them in my system under 3KHz right now. Above 3KHz, they might be the best sounding drivers out there.

Greg
 
Not sure how loud you listen and I know CTC suffers, but I do not like the Raal below 2KHz. I don't even use them in my system under 3KHz right now. Above 3KHz, they might be the best sounding drivers out there.

Greg

lm not doing a MTM, it will be MMTMWMW like StigErik (or TMMMWMW). M and MW will be in pairs with the cones from each pair facing opposite directions. That's why I am looking at using the acrylic shown above, each pair of the same drivers would be mounted together one facing forward the other facing back.

Not sure what the crossover will look like once the drivers are mounted. What size mids are you using?
 
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lm not doing a MTM, it will be MMTMWMW like StigErik (or TMMMWMW). M and MW will be in pairs with the cones from each pair facing opposite directions. That's why I am looking at using the acrylic shown above, each pair of the same drivers would be mounted together one facing forward the other facing back.

Not sure what the crossover will look like once the drivers are mounted. What size mids are you using?

Right, I got that your were going the S.E. route, but the higher you cross, the more you need to consider CTC even btw the two mids or btw the mid and the Raal. I'm running dual Neo10 planars. I'd could turn one of my mids around too but it wouldn't buy me anything! Haha, got Stig on that one.

Greg
 

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Greg there is nothing to stop me doing something similar to what you have done if it isn't going to cause M-T issue (see pic)

BTW very nice speakers you have there... Do you find the planars harsh when used with the RAAL? Also is that one solid block of wood?

Curious as to what you used for your bass, and if you feel it is in the same league as the other speakers (distortion, quality wise etc)
 

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There is one good reason for doing push pull with both woofers and midranges, and that is distortion reduction. Odd order harmonics are reduced with a factor up to 10 because of phase cancellation of the distortion products between the drivers.

That would be even order cancelation.

This the main reason for having the drivers opposed.
 
ohhh . I see:rolleyes:
And what do they say about reflections from the basket and the cylinder
( the magnet ) ? Are they less important than distortion cancellation ?

You need to think about the wavelengths involved. He's looking at crossing at 2k which is a wavelength of 6.75".

As far as woofer isolation, in my application the naked driver "scaffolding" is mounted to the u-frame, but the wire suspending the drivers hangs from rubber grommets. That plus the "swinging" action of the cable ensures little to no vibration transfer from the woofer to the upper drivers. They pass the touch test at least when the woofer is doing 40hz, which is as scientific as I'm willing to get here.
 
Greg there is nothing to stop me doing something similar to what you have done if it isn't going to cause M-T issue (see pic)

BTW very nice speakers you have there... Do you find the planars harsh when used with the RAAL? Also is that one solid block of wood?

Curious as to what you used for your bass, and if you feel it is in the same league as the other speakers (distortion, quality wise etc)

Those Illuminator mids are soooo cute! I can't believe both of them basically fit right next to the Raal. Even of to the side, you have to be aware of the CTC distance. Like I said, I'm not using my own advice and crossing technically too high at 3KHz, but I trade off poorer off axis performance for easier task for the Raal. Plus, I think meaty snare drums sound more powerful with more of their top end coming from the Neo10 than the Raal. It's just my preference after trying every combination possible.

Using the Neo10 with the Raal is in no way harsh. Just the opposite actually as long as you get off of the Neo10 by at least 3KHz, they are smooth as silk. No break-up like a metal or hard paper cone.

The wood is 4 layers glued up. Bamboo plywood-mdf-bamboo plywood-baltic plywood. first layer is tung oiled, back 3 are Rustoleum speckled finish paint.

Woofers are B&C 15NDL46. see here:

B&C 15NDL76 15" Neodymium Woofer 294-683

I started with Lambda Dipole 15, but sold those and went with the lower Qts B&Cs.

Greg
 
lol problem is they are too cute... I am having trouble convincing myself that they are big enough to handle the job of a mid.

If I was using a typical tweeter that crossed over higher, I could justify having them in there and just slip something a bit bigger in underneath to fill in the bottom end.

Their sheer physical size is mucking with my head because in the past small speakers just didn't do low frequencies. I was toying with the idea of yanking them out of there and replacing them with the 18WU's, but as you can see from the graph they don't go much lower and the graph is no where near as smooth.

Problem is getting my brain to jump from a 120mm mid to a 393mm woofer.

Currently I am running 2 x 8ohm 12MU's in parallel, but I am wondering if perhaps it should run 2 x 4ohm 12MU's on separate amps, and just split the signal from the Digital X-Over. (I have 6 x 8ohm and 4 x 4ohm available)

Is this too big of a jump for OB or is it just me?
 

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