DIY: Dipole 8" array with Neo 130cm Ribbon

[Bent]

Hi!

I used to ferquent these threads quite a bit and had planned my "Ultimate Speaker" for years but time wasnt on my side. Anyway, Having made it a priority, I have finally cut up all the wood, have all the components ready to go. It helped alot having a neighbour who works at a private school with a programmable router to make the jigs to route the speaker holes!

Anyway, I guess I could find my old thread, but here is an update with a photo taken this moring of me and my front panel!

Each Speaker is as follows:

1 x Tony Moore Neo Magnet Ribbon (96db/watt @ 1m), Dipole
8 x HiVi M8a Woofer, Dipole
2 x Peerless 12" XLS 830500, 100 Litres sealed/ported option
1 x KSC Plate Amp. B&O Icepower 1 x 250A, 1 x 500A, 1 x 500ASP and DSP.

There are two concessions in these speakers. The power on the woofer section and the choice of Midwoofers. Will see how we go with both and will change if needs be.

I hope to complete within 2 months, probably will be 3 or so....

[Few]

Hey Bent, lookin' great! I'm taking forever to complete my own 8" woofe arrayr-based OB system, but it'll use an ESL for the upper frequencies instead of a ribbon. It's already clear your system is going to look very nice. My 2-3 month long project has just completed its first year of "under construction" status , --if I could find a "hang my head in shame" smiley I'd throw that in as well. It looks like you're on a roll, though, so I'm looking forward to monitoring your progress.

BTW, I'm unfamiliar with Tony Moore ribbons--perhaps because we live on (almost) diametrically opposed points of the globe. Can you direct me to any information?

Good luck on your project. It really does look like it'll be well worth the effort.
Few

[Bent]

Hi FEW, do you have a link to your photos?

There is a webpage for Tony Moore - "Ambience or Speakers". The ribbons are not available commercially, he was nice enough to sell me a pair of his top of his range ribbons.

I could not make up my minds for ages on the final design I would run with......that is what took the biggest chunk of time. At least you have started - I bought the midwoofers 3 years ago....talk about shame!

I also want to make these speakers look as "Wife Friendly" as possible, so the final finish will have to be nothing short of exemplary. I will probably get the finish done proffesionally to guarrantee this and save some time.

The front panel is to be stained to several shades darker than Jarrah - Jarrah is to be used on the sides and the wood is there on the left of the photo. There is an optioon to change the wood for the sides and go light instead of dark....my house has alot of Jarrah in it though (ballestrades, Dorr frames, Floor etc etc).

[chinsettawong]

I'm sure the speakers will turn out very beautiful. Please keep us updated and do post a lot of pictures.

Wachara C.

[LineSource]

Hi Brent,

I've seen a few ribbon + cone speakers that put the delicate low mass ribbon on a physically seperate baffle from the robust higher moving mass cone speakers. This isolates physical vibrations, and also allows the option to turn the midbass array at a different angle from the ribbons relative to the listener.

Some midbass and bass line arrays add steel struts to strengthen and weight the baffle, and/or include sand filled volumes to absorb vibrations with friction heat.

cheap joke: Rock and Roll should come from the music and not the cabinets.

[Few]

Here's a link to the thread I started back in the early stages. I've not done a good job keeping it up to date, primarily because I've been focusing my attention on the ESL side of the project. There have been so many false starts I didn't want to waste readers' time--or embarrass myself unnecessarily--by documenting every wrong turn I've taken. Things are making a bit more progress lately, though, so I'm hoping to post some updates.

I bought my woofers and magnet wire (for the ESLs) well before the start date I alluded to earlier, so your three year head start isn't far off from my situation. Let's just call ourselves "careful" and think of it as a virtue. Your final result is sure to be more than wife friendly so keep up the good work.

I'll be very interested to hear about your experiences with the B&O Icepower modules. I may be looking for a new way to drive my ESLs.

Maybe we should start an 8" woofer array OB builders' club... I really think 8" (mid)woofers hit a sort of sweet spot. Big enough to move some air, especially when there are several of them, yet small enough to keep break-up modes out of the critical range. Very Zen, or perhaps that should be Goldilocks.

Few

[Bent]

Hi FEW, thanks for the Link.

Speaker look very cool, cmon then and finish - I will race you!

I think I might try the "pour" technique for the front panel, that was a great find, and I have heaps of solvent based urethane from when I did my Jarrah floors!

I dont have any cool curves in my panel. One day I would like to do a monopole setup with curved cabinet - really arty!

[Bent]

True about the 8".

My rational was regarding "beaming" of cone break up and the 2nd and third harmonics. If I cross these at 300-400Hz, I can eliminate most of the nasties - that is my theory anyway. Has anyone ever wondered about this on this site? If so I havent read it. Beaming on an 8" is around 1500Hz right? Cone break up for the M8a is near this point too.

I plan to equalize the 8" array flat to 40Hz and then cross low order (1st?) at 60-70Hz with an ultra steep step at 40Hz. Hopefully to maximize the Dipole bass.

This technique (cross over at low order and then use a steep filter) is one I would like to experiment with betwen the Ribbon and the Array also.

Since I have a powerful DSP, I can do everything like this, correct for room nodes, correct for phase, everything!! This way it is stand alone and can be used in almost any room!

[Bent]

LINESOURCE:

I did initially design this way (separet baffels for mids and tweeter) however it wasnt practicle size wise. I can still see many benefits though.

My sub section actually sits at the bottom (500mm high, 615mm deep, 500mm wide) and the lower two 8" mids fire out the side. I will explain via photos in a few weeks.

So far all you have seen is the front baffel :-)

[cowanaudio]

G'day Graeme

I'm delighted to to hear you have finally made a start on this project of yours. It's funny, I've just made a start on a high efficiency line source planar system, too. I have some 2M long neo planars that I'll be building in with six Peerless 830669 per side. This will all end off in the games room down the other end of the house from the Unity system. Listening to the planars in monopole enclosures at the moment and they sound great. Just a touch of eq required to get them +/-1.5dB at the listening position from their 300Hz X/O on up.

Don't go too low in the crossover to your ribbons.

PS. How about I give you a deadline? I'll be over in Perth in 12 months. Have a 90th birthday party to attend. Think you can get your system built in time for me to have a listen?

Cheers

William Cowan