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AE Dipoles "Eloquence"- my 5th dipole project                                                                                                                                                  I                                                                                                                                                                                                             DANISH 

Latest update - 18 January 2020

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Acoustic Elegance Dipole 15 - my 5 th dipoleproject! (started april 2015)

I have made my own speakers since the 70’ies.  This is my dipole system no. 5, and my DIY speakers no. 25 or close. Before I describe the new dipole system using AE woofers and midrange drivers, first some history.
If you want to go directly to the new system, please scroll down..

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Each dipole was with four 10" Peerles woofers mounted on two solid baffles. Two each side 10" apart. I did not know about dipoles at that time and of course it did not work. Maybe some EQ would have helped, but no, that was not a part of the project.  Inexperience is expensive, but you get wiser!

2001 - My next dipole project was much better. The Delta Dipole project was published in the Danish magazine HIGHfidelity in 2001 (I was editor and reviewer from 1989 to 2009, when they closed down). 2001 - The Delta Dipole. This one used Eight 8” Peerles drivers each side in a modified M-baffle (slot loading). They were used with active X-over and EQ. Stunning results.  Had a visit from a well known Danish High End manufacturer, who suggested that we made it public. We just had to narrow it down from 60” to 10” and put some shiny solid steel plates on the sides! Sure he did not understand the principle. The midrange is the famous 3" ATC dome. The top 3/4" dome is from Oscar Wrønding  - OW2.  Later the ATC was substitued with a 6,5" from Focal, which was a much better choise is this speaker. This DIY speaker project  was published in the Danish HIGHfidelity magazine. I was editor and reviewer at that time.

I

n 2004 the new speaker “Tantalizer” used six 12” Peerless woofers each side. This was a folded “U”-baffle. Lot more power and extension. This time with a Behringer digital X-over and EQ.

As can be seen from the picture there was two woofers on each side and two on the front. The back was open. The 10" midrange is from  French PHL Audio and the ribbon is from Aurum Cantus. 

On the left a look into the "machine". Through one of the side wooferholes you can see the 4 opposite woofers.  The dipoles  covered the range  from 25 Hz til approx 200  Hz.

The tower dipoles "Turbulence" - LAT 2000 

These were my “all out” giant open baffles using four Tymphany LAT 700 each side. They were 220 cm (87”) high and weighed 100 kg each (240 lbs). Each LAT 700 is equivalent to 2 x 12” woofers, so in total eigth 12" woofers each tower. Total surface area approx. 4.000 cm2 (660 square inch) each tower. This system aptly named “Turbulence” could producer absolutely earth shaking lows down to 20 Hz in room. Playing Yello was a physical experience where you could feel your clothes moving.

This project was also published in HIGHfidelity. I do not know how many there were made. I think smaller version witth one or two LAT 700 were more popular.

I used them with a Danish digital cross-over from Ground Sound. The power amp diriving the towers were a 300 Watt Ground Sound designed for PA use. Measurements (see picture below) showed 20 Hz to be 6 dB down in room. with approx. 10 dB eq.

2011 I moved in with my girlfriend. No room for 220 cm high woofer towers, so the next project was a closed box system in a more room friendly size. But the dipoles still lured in the background.

The rule used to be, that each 3rd year i made a new set of speakers. This was how it used to be, but maybe i have reached the end of the road? This time it is dipoles again. They do something special and couple to the room in a way i like. At the same time you get rid of the "box-sound". 

I read that the American speaker manufacturer Acoustic Elegance made the best woofers for dipoles. But they were expensive and delivery time could be long. But now all four Diple 15 are in place in very solid and heavy baffles. The baffles weigh approx. 70 kg (154 lbs) each. 

The AE Dipole 15 has been designed for dipoles. In other words with a high Qt around 0.85 and a low Fs - 20 Hz. At the same time it has an underhung voicecoil with a linear stroke of +/- 12 mm (+/- ½"). If you accept that the voice coil leaves the magnet system the mecanical stroke is +/- 18 mm. Please note that this happens without any noise or ratteling, a thing that could not be said about the Peerles drivers i used in my older dipoles. The sensitivity is high so max stroke happens at around 100 Watt, which is the max recommended power for the double voicecoil. The two woofers have been connected in parallel / series, which gives an 8 ohm load. 

The speaker baffle is made of 2 layers of baltic birch ply, each 21 mm thick (0.9"). On the back there is a solid ash frame 26 mm thick (1.1"). Each side have a hinged 10 mm (0.4")Makrolon plate. (A very solid material used for caging wild animals - rhinos and elephants!) The plates increase the 46 cm wide baffle wiht 22 cm in each side. Total width is then 90 cm (36") and height 120 cm (48"). 

Two Dipole15 Acoustic Elegance. 
One Accuton C173N 6,5" midrange
One Scan Speak Beryllium dome.

It all runs through my DEQX HDP-5 which is a combined preamp, X-over, DAC and room correction. 

Midrange and treble is driven by a four channel Holton Precision Mos Fet amplifier (DIY). It puts out 4 x 60 Watts / 8 ohm. It contains an 800 VA transformer and 200.000 uF CLC PSU. There are plenty of current reserves. 

The woofers are powered by a 2 x 150 W Maranz amp. A big 2 x 350 Watt Holton poweramp is under construction.  

Why new speakers?

Yes, I was very satisfied with my old 3-way acoustic suspension system using two 10" woofers from SB Acoustics (Wide Baffle project - in Danish). But dipoles have always had something special in my view. So back to the dipoles again. The AE drivers got really fantastic reviews and looked like the right thing. But 9 months delivery time! After having borrowed a set of the dipole 18 and made a simple baffle, I was hooked! Four Dipole 15 were ordered thruugh a Swedish group buy (Denmark is very close to Sweden). We got a fair price, but still delivery time was 9 months (a tough pregnancy) End november 2015 I received my 4 woofers.  http://aespeakers.com/shop/dipole/dipole15/

During the waiting time i started  the heavy wood work. The new baffles are SOLID! The same thing can be said about the base and everything else on these speakers. 

I have seen many open baffles made from a single layer of MDF or plywood. They are coupled to flimsy feet so they stand rocking for minutes threatening to tumble over. 

Not like that here. For the center baffle two layers of 21 mm baltic birch plywood were glued together. (42 mm/1,7").

On the backside i put two 28 mm (1,1") thick pieces of solid ash along the outside. On the front there is another thick frame of solid ash. This time two layers of 26 mm, totalling 52 mm (2"). Seen from the side the baffle is 112 mm thick (4.4").

The base is constructed from two layers of solid ash. It is glued and bolted to the baffle.  

Two reinforcing flanges are each made from two layers of 21 mm birchply. They connect with the base at a point right under the midrange. The distance between the flanges has been calculatied so that the big magnets from the woofers fits in between. 

This reinforcing may not be necessary, but it looks good and better sure that sorry. Don't forget there are big forces i play here as the two woofers will move at lot of air og put quite som energy back into the baffle.

This "finished" speaker then played for at few months. Everything worked according to plan. The sound in my livingroom was really good - especially the lower frequencies felt correct and with lots of energy.   

But then ......

Denne

As mentioned above my speakers normally "lasts" 3 years. Not quite that long this time! Based on the good result with the Dipole 15 i ordered two Acoustic Elegance TD10M midrangedrivers. But why? I had been using the Accuton for many years and was very pleased with it. But no, something new had to happen and tonally i thought that the TD 10 M would fit better with the Dipole 15. On top of that the TD10M had some really good reveiws on American sites, where frequency measurements as well as distortion showed amazing figures. You can find specs for the TD10M on the AE site.

At the same time I also "happened" to invest in my dream top range driver! Poul Ladegaard as well as Ole Lund Christensen (Jern Speakers) have been using this unit for many years for professional applicaitons as well as in high end hifi systems. As Ole told me: "This is the best high end driver in the world, you will not regret it".

See frequency plot below. My own measurement.

Stage Accompany SA 8535 is a big Dutch planar driver - NOT a ribbon! It's been improoved through many years and now stands as something quite unique. Frequence range from around 1.2 kHz up to 30 khz. Sensitivity 102 dB/1W into a totally flat impedance of 13 ohms. The price here in Denmark is 14,000 DKR for a set (approx. 2,200 US$) A lot of money, but with this driver it is possible to cross over at a fairly low frequency to the TD10M, which will fit perfectly with my plans. With the DEQX HDP-5 digital x-over I run 48 dB/oct, so the planar driver wil not be stressed at all. 

The the new baffles should simply just be taken apart and made 19 cm (8") higher! There should be made room for two new bigger drivers. This turned out to be a much bigger project than i had imagined. It also caused a broken big toe (5 places!) as i dropped one of the 70 kg (150 lbs) speakers on my foot! Apart from that some of the reinforcement on the backside did not fit with the new drivers. A lot of problems, but they were solved.



The total Dipole 15 mk. II speaker now looks like this:

Acoustic Elegance Dipole 15 x 2. 
Acoustic Elegance TD 10M  10" midrange
Stage Accompany SA 8535 planar high frequency driver

I still use the old cross over points at 220 Hz and 2,200 Hz. But new measurements will be made, to show where the optimal points shall be placed.  

The remodelling!

It was with a bleeding heart i put the big cutter to my speakers. But it had to be done. They should be 19 cm higher to make room for the new drivers. At the same time i had to cut out a big piece of the baffle itself to make room for the big magnet on the backsite of the SA 8535. This was a bit more difficult than I had foreseen. The big heavy speakers should be mooved to my workshop in the cellar, and solid ash and plywood is heavy. It is also very hard to work with.  

Here pictures of the speakers before and after the makover. The two front solid pieces of ash have been removed. Don't think they wil come back. 

At last the allmost finished speaker looks like this ....



Around the Stage Accompany planar small strips of velvet has been glued on. This hides the rough edges where the leather has been cut. 

The baffles are normally placed quiite close to the back wall, but when l listen more seriously they ar moved out into the room. The next thing wil be some room treatment behind the speakers. I just have to convice my girlfriend that this is a good idea! ;o)

Just put them on a weight. 80 kgs - 176 lbs each. Solid and heavy.

Latest picture - january 2020

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