A first crack at dipoles

[Roscoe Primrose]

OK, so I just finished at first cut at a full dipole system (OK, so it's only dipole up to 2.6K). System consists of dipole subs based on Linkwitz's Phoenix woofers, but scaled up to handle Pyle PPA15s. Woofers are powerd by a pair of Pars Express 250W sub amps, 300-796. Main panels have 6 Audax 6.5" drivers, Parts Express 299-434 and an Audax dome tweeter, PE 276-106, crossed over 2nd order at 2.6kHz. Woofer to main panel xover is at 100Hz.

There is currently no EQ applied to the system, give it time. Panels are powered by 2A3 single ended amps, about 1.5W/channel. I'd estimate panel sensitivity at 95dB/W/m based on the fact that I'm not padding the 96dB/W/m tweeter at all and it's only ever so slightly hot as it sits.

How do they sound? Well, considering the very low cost of the panels (the 6.5s were only $5.65/ea) remarkably good. They're not as dynamic as my normal horn system, but that's to be expected, especially with only 1.5W/channel driving the panels. I think a little dipole EQ would be a help both for the panel & the woofers, but I've still got a lot of playing around to do in that area. Imaging is quite good, with very good depth that extends well beyond the front wall of the listening room. The speakers are very non-fatiguing, which is surprising considering that the tweeter is slightly hot, but at least it's not peaky.

Pictures here: Roscoe's Dipoles

[5th element]

Pretty impressive looking beasts you've built youself there. Good to hear they sound good too!

Depending on the quality of the tweet you can have it turned up quite a bit over the mids and it wont fatigue, it just sounds brighter.

[tom1356]

Very cool! I don't know why they are not more popular with the DIY crowd.

I recently added a second pair of 12" woofers to mine and I can't believe how good they are. Clear tight bass flat to 30Hz with no EQ and a passive pre driven with 300b mono blocks. This system breaks all the rules and sounds incredible.

Since I built the dipoles my wife suddenly wants to listen to music.
2-3 hours a night now. It used to be less than that a month.

I bet you inspire a lot of people.

[Roscoe Primrose]

Originally posted by 5th element
Pretty impressive looking beasts you've built youself there. Good to hear they sound good too!

Depending on the quality of the tweet you can have it turned up quite a bit over the mids and it wont fatigue, it just sounds brighter.

The tweet is an Audax TW025A12 3/4" textile dome tweeter. Not the be-all/end-all of tweeters, but it's hard to find an affordable, decent sounding tweeter that can keep up with 6 6.5" drivers with a passive xover. I'd never heard this tweeter before, but it looked like a good match on paper, for once paper and sound actually agree ;-)

I'd never heard a non-planar dipole before (I've owned Maggies & Acoustats before though) so I didn't want to break the bank on the "proof of concept" pair, heck, the two tweeters cost more than the 12 6.5s...

Originally posted by tom1356
Very cool! I don't know why they are not more popular with the DIY crowd.

I recently added a second pair of 12" woofers to mine and I can't believe how good they are. Clear tight bass flat to 30Hz with no EQ and a passive pre driven with 300b mono blocks. This system breaks all the rules and sounds incredible.

Are you running dipole subs as well? From the 300Bs? That's a heck of a choke for that low an xover!

Since I built the dipoles my wife suddenly wants to listen to music.
2-3 hours a night now. It used to be less than that a month.

I bet you inspire a lot of people.

Ha, my wife's in the 2-3 hours a decade camp. I don't expect to notice much of a change there. One of the guys in our local DIY group (the only one who's heard mine yet, and before they had ANY breakin time) is already working on a set of his own, although he may be using different drivers.

I fully expect these will end up in the home theatre, I do miss the horns in the main system. I plan to build a better pair if dipole subs to go with the horns though!

Peace

[JoeBob]

I'm a convert ot the dipole crowd as well. Don't give up and if you try another more ambitious pair I'm sure you won't be let down.

As for the bass, dipole bass is what everyone raves about, and with eq it can be very easy to do, although the great bass isn't what I like most about dipoles, the midrange is just superb if done right, I've never had a speaker "just be there" and not seem like the source of the music the way some dipoles can...

Getting back on track, those do look impressive they do. I hope you enjoy the sound.

[tom1356]

Originally posted by Roscoe Primrose

Are you running dipole subs as well? From the 300Bs? That's a heck of a choke for that low an xover!

Yes I am running each three way 5 driver system from the 300b mono amps alone. Plenty of volume and bass. Nice small (24" wide 32" tall) baffles for the woofers. The mids and tweets have seperate small baffles for a total of three baffles per side.

Originally posted by Roscoe Primrose

Ha, my wife's in the 2-3 hours a decade camp. I don't expect to notice much of a change there. One of the guys in our local DIY group (the only one who's heard mine yet, and before they had ANY breakin time) is already working on a set of his own, although he may be using different drivers.

I fully expect these will end up in the home theatre, I do miss the horns in the main system. I plan to build a better pair if dipole subs to go with the horns though!

Peace

I am almost as surprised as she is with her new found interest.
Will you do a dipole center for the HT setup?
Dipole bass is so sweet.
I bet they just get better with some hours on them.
Good luck with the new ones.

[Nuuk]

I recently added a second pair of 12" woofers to mine and I can't believe how good they are.

Tom, could you give us full details: drivers, crossover, housing etc?

I have temporarily added a small sub to my OBs and the effect is amazing but my eventual goal is dipole bass when I sort out how to do it.

I too am surprised that dipoles are not more popular with the DIY croud!

[Nuuk]

Roscoe, nice work but you do realise how envious you make us all in Europe etc when you talk about buying 6.5 inch drivers for under 6USD

[Leonidas]

Your setup looks great!!! and very impressive !!! ,
Please tell some more about X-over etc.
Do You use a "Bessel-array" ? And if you did ; how did you manege to regulate the impedance off the midrange for your amps?
Please help me out , I'm planning an "open baffle line array" for a long time now.

[tom1356]

Originally posted by Nuuk


Tom, could you give us full details: drivers, crossover, housing etc?

I have temporarily added a small sub to my OBs and the effect is amazing but my eventual goal is dipole bass when I sort out how to do it.

I too am surprised that dipoles are not more popular with the DIY croud!

Be careful what you ask for you just might get it.

These are a work in progress...
The only thing facing the listener is the tweeters.

This is a pic of the left speaker from the listening position.
The woofers are vintage 12" Pioneer TAD with a Graphite cone, faraday ring, and dual voice coils. One 4 ohm voice coil in each driver plays from 40 Hz down. The other 8 ohm VC plays from 300 Hz down. They were designed to do this. The two woofers are wired in parallel.
The midrange is a vintage Pioneer TAD 4" with a Boron/titanium cone, and faraday ring. They are mounted on Corian spiral shaped baffles covered in leather. They are run full range. The baffle has a natural low roll off at 300 Hz. They play up to about 12 kHz. I am about to start the process of incorporating a second set of midranges to wire in series which will allow me to use less L-pad attenuation.
Everything is wired with single strand silver wire.
The Tweeters are PT-2 planar ribbons placed back to back. They are wired in series to help reduce the need for L-pad attenuation.
The crossover point is 12 kHz.
I have been involved in retail high end audio off and on since 1985 and these are the best speakers I have ever heard. They do have a way to go till completion and that makes me smile very wide.
If you are looking to play pipe organ music and hit 20 Hz than you will need a sub but other than that most people will be very happy with these.