EXCEL22DXTCompact large speaker
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|Hersteller / Marke der Chassis||Seas Excel|
Pictures from the Loudspeakerbuilding community to this speaker kit
Corresponding articles from our community
Music is part of our life, and everyone has their own soundtrack. Some started out with (mostly) black discs on a turntable, while others had an audiotape in a little plastic case (also known as a compact cassette). The younger generation began their soundtracks with mirrored silver discs or went straight to files, and more recently streaming music.
Over the course of time, listening habits changed, sometimes more and sometimes less. The playback devices changed, too. While in the 60s it was hip to have furniture for playing back music in the living room, in the 70s that turned into a music system with two speaker boxes, which many times were as big as coffins. The idea of the WAF had not yet been invented when it came to playing recorded music.
The ’80s came up with the portable private music room. No, not the smartphone. Just as big and clunky as the first smartphones, though (like the Nokia Communicator), were the first Walkmans. The speaker boxes were no longer so important, since headphones shaped the soundtrack of everyday life. In the ’80s, boxes grew smaller and narrower, and had to conform to interior design trends. The WAF was born. Today the soundtrack of our life often comes out of yogurt cups, almost invisibly imitating the soundscape of a shopping center and often accompanied by wobbly sounds from bluish glowing boxes. But let’s go back to the generation that grew up with black discs on a turntable.
May I present: my father. His listening habits haven’t changed in the last few years, but the focus has shifted. Less rock, more jazz and opera. Over the last 20 years, the listening experience for his soundtrack has been largely shaped by the wonderful JBL 4301Bs. These boxes, with a two-way bass reflex system, were distinguished by their extraordinary voice reproduction. No wonder – the things were designed for studio use in radio or television productions.
Now, after more than 20 years, the surround material in the woofers was worn out again. A professional repair job, including replacing the electrolytic capacitors in the crossovers, is fairly expensive. A decision was made: he needed a replacement! From helping with my DIY projects, he was familiar with the advantages of DIY boxes: you can combine your desired sound with the WAF.
But what should we choose? The offerings in this online magazine are very well stocked with 2-way bass reflex systems. The standard is the “Blues Class.” And people buy them “sound unheard,” too. After a few considerations, the choice fell to the dual exhaust unit: the Seas Excel 22 DXT. The reason was the size of the bass mid-range speaker, since he didn’t want it to be smaller than that. The behavior of the new box needed to be similar to the old one – hardly any dependence on the angle, and a little more pressure in the bass if necessary. Picking up the assembly kit turned into a multi-generational family outing: Grandpa, son and grandson. After a surprisingly long visit on the couch in the famous listening studio, the family drove home with a big box.
However, the double exhaust unit (see picture above) failed the WAF test, and it was denied access to the living room. The two holes were quickly transformed into a narrow line, and the boxes got a foot in the door. Now it was time to finalize the outside appearance: we decided on beech to match the existing furniture. Whew – the WAF was nearly achieved. Since the multiplex edges do not really resemble wood, we used a small visual trick: the baffle board was attached on top of the walls. Now the boxes were allowed into the living room, and they are even a little smaller than the JBL 4301B.
My father was given a copy of the plan. The reinforcements were based on an old civil engineering tradition: safe is not safe enough. Good thing he knows a carpenter who is reliable at cutting wood to size. It’s less good when the engineer mentality takes over, and the planned 18-mm multiplex (MPX) is replaced by much sturdier 20-mm multiplex.
Once my father had gotten the 3-D wood puzzle home, I was allowed to take a crack at it. How were we going to glue it, my father wondered, without any dowels and with just some Ponal joint glue. Finally he built up enough confidence in my explanations, and we were able to start on the practical part. Half an hour later, the first pieces were glued together. It’s much easier with four hands. My father glued in the rest of the boards himself.
The milling work on the front was finished with a division of labor: I worked with the router while my father held the vacuum hose close to the router head. It’s worth mentioning here that beech MPX turns out to be very hard. The cost-effective router set did not hold up long under the load. The 6-mm slot cutter broke off while cutting out the chassis opening. Its 8-mm comrade took over the job, but with some reluctance, and very dully after cutting two openings. Still, it finished the job, even though it got fairly hot while it was working.
The 16-mm slot cutter gave the beech MPX the respect it was due, giving off more than a little smoke in the process. While cutting out the bass reflex slit, it failed completely on the second baffle board. Since it was getting pretty late, we moved the next routing session a few days later. Plenty of time to buy some new cutters.
My father is one of those people who can’t stand an unfinished project. So he grabbed the plan and the unfinished baffle board and drove to a friend’s house – the cabinetmaker with the CNC router. The master was supposed to cut a quick line into the wood with his CNC tool. Who knows why, but the baffle board didn’t stay in its place in the CNC router – while the router head followed the correct path…
A new piece of 22-mm beech MPX was quickly conjured up from a corner somewhere, cut to size and firmly clamped into the CNC. A cup of coffee later, the baffle board was completely done.
One final detail was planned to decorate the boxes: the bass reflex channel needed to be black. A couple of passes with the brush and it was finished. But we hadn’t considered the merciless capillary effect. Dry wood fibers can also resist gravity and absorb the paint. Then you get ugly little black fringes under the crepe band, which can’t be removed even with sandpaper.
While my father was busy gluing the wood boxes, his grandson leapt into action. Since he had enjoyed soldering the crossover for his own boxes, he was happy to help his Grandpa build the new boxes. A couple of coils, capacitors and resistors were quickly distributed among four little boards, attached with hot glue and soldered together. An almost eleven-year-old can do that all by himself. I just did the final inspection, and there were no complaints.
Installing the chassis would almost have been a routine step, but Seas had a little surprise for us in the form of the basket design. The outer diameter of the top edge of the basket is about 0.7 mm smaller than the bottom edge. Which is only a problem if the opening has been cut out very, very precisely. We didn’t notice it, either, because in the trial with the magnet on top (easier to hold), the chassis fit wonderfully. Still, this minor hitch was quickly fixed with a little sanding.
Transporting the 18-kg boxes from home office to living room didn’t take long. It was fast to connect the boxes with a loudspeaker cord and the right plugs, but it was already too late for an extensive listening session. That came a couple of weeks later.
My father set up this longer listening session for me, so that I could hear some of his own personal soundtrack. To make the transition easier for me, we started with a piece from the late ’80s: Tracy Chapman, “Talkin’ Bout a Revolution.” A singer with a distinctive voice and an acoustic guitar. It sounded like she was putting on a private concert for us. Every detail was there, from changing the chord fingering to slapping the strings and of course her voice, right there in the living room with the two listeners. Next, a Paul Anka CD made its way into the player. The name didn’t mean anything to me, but the Seas knew the sound, and brilliantly recreated the atmosphere of the 1960s. The singer of “My Hometown” was even positioned at the right center, in front of the drums in the background on the left. The plucking of the double bass at the front right was there, along with the piano behind it. It’s amazing how much life there is in those old recordings. My father was completely lost in the rhythm of his younger days, and he got out another CD: the King was up. Listening to “Don’t Be Cruel,” it was clear to me why Elvis Presley so successfully influenced his era. The King’s deep and warm voice, reproduced by the Excel 22 DXT Ensemble, was brimming with emotion and clarity. Behind him was the backup band, and throughout we heard the typical sound of a plucked deep double bass, which effortlessly and calmly set the rhythm together with the drums.
A musical shift was announced with Dave Brubeck, “Take Five.” It’s incredible how gentle a saxophone can be. And since we’re almost in the jazz corner now, we followed it up with a CD from a local band. The Foss Dolls played “Ain’t No Sunshine” at medium indoor volume. The reproduction of the deepest electric bass notes knocked me over. You could almost reach out and touch the vibrations from the fat strings. That’s what bass precision means. My BOSE sound system in the car always goes on the fritz there, slinging bass mud around the room. Even my son’s SB12ACL (SB Acoustics) gives up the ghost at slightly higher indoor volumes when it’s faced with this slowly played electronic bass. But in my father’s living room, the Seas Excel drivers played their cool “Slow Sound,” and wonderful vibrations filled the room. I felt like I could reach out and touch the striking and fading out of the strings.
In contrast to our previous session, there now came some music from the classical department. We started with the “Canto Gregoriano” and “Puer natus est nobis.” They transported us to an enormous church nave – the living room seemed to have grown. It might have been the recording or the loving detail from the boxes, but we were able to pick out the individual monks’ voices. You just need to take some time and pay attention to the details. Since I’m not a classical fan, I didn’t share my father’s enthusiasm for opera recordings. The only thing I remembered was Anne-Sophie Mutter with the Carmen fantasy “Gypsy Melodies.” Until now, I had no idea what high notes a violin could play, and without being annoying. Quiet or soft – the boxes didn’t care.
I also did a small sound check by myself. The Metallica song “One,” played by four Finnish musicians on cellos, needs to be heard at least at a higher indoor volume. The volume knob was quickly moved to 1:00, and then we started. The power of “One” was paired with Nordic precision. Each cello had a place on the stage. Then came the plucking of the strings in the first chords – you can almost hear the finger movements. After that, the power came from the #22 and aligned itself with the bows sawing across the strings. Although it didn’t seem quite as loud to me, the visitors in the garden on the other side of the building were disturbed.
This is the “Slow Sound” from Seas Norway: no detail of a good recording is left out, whether it is loud or quiet. But the listeners should take the time to hear every detail and practice a little “Slow Listening” themselves.
The Seas Excel 22 DXT loudspeaker kit can be ordered here.
(The assembling kits always include all speakers, crossover components, terminal, damping, cable for one box. The wood for the cabinet is not included.)
Excel 22 DXT
Excel 22 DXT
Hermann? Right, of course, it’s Hermann! It’s hard to say why I remembered his name as soon as he walked into the listening studio – like the man himself, it just resurfaced. We agreed that his last visit must have been almost 15 years ago, although I think just under 20 years is a more realistic guess. Back then, he had picked out my first transmission line with Seas equipment, which he had used happily and to his great satisfaction until just recently. But the teeth of time had been gnawing away at his loudspeakers too, and the surround material on the basses had been almost swallowed up. No, no, he wasn’t thinking of a repair – sometimes you have to let go of the old, even if you are very fond of it and always enjoyed its company. Nothing lasts forever, and new things have the great advantage of making it easier to break free from well-trodden paths. While good old groovy rock music was once the main musical element where he felt at home, recently he had started adding a little classical music to his faithful turntable, along with more and more jazz. “Of course, old age,” I reassured him. I had reached that point long ago myself. Of course, that was by no means the only reason to completely replace the box, because of course it could handle jazz and classical music too. Doris – hands down the best wife in the world, he said – had also wished for some smaller boxes, so he was happy to oblige. As a long-time reader of the magazine, he had been attracted to the smaller two-way speakers from the Blues class. But being used to large boxes, he was having trouble coming to terms with a membrane area that was almost cut in half. The big SB 18, Doppel 7 or Phase 34 would have helped, but those are free-standing boxes too. The compact version of the Kera 360.2 wasn’t really what Hermann considered compact. If we had one #20 instead of one #17 in a comparable-sized cabinet, with a sound level that could still handle the old rock music, that would be the box for him. Oh dear – I didn’t have anything like that on offer because it doesn’t really work. A #20 needs a certain amount of air volume, and it’s almost impossible to connect it to a tweeter because they can’t be separated out at a deep enough level. When Hermann left that day, I promised him I would work on fulfilling his completely understandable request.
Measurements as a Zip-file
|Membrane:||coated paper||Air gap height:||6 mm|
|Surround material:||rubber||Winding height:||14 mm|
|Pole piece hole:||nein||Mounting holes:||6|
|Centering:||raised flat spider||Outside diameter:||220 mm|
|Shielding:||no||Installation opening:||144 mm|
|Voice coil:||39||Milling depth:||5,5 mm|
|Voice coil former:||aluminium||Installation depth:||106 mm|
|Frequency response and phase||Impedance||Frequency response under 0/ 30/ 60°|
|Distortion for 90 dB||Step response||Waterfall|
Measurements as a Zip-file
|Qts||0,72||SPL 2,83V/ 1m||92||dB|
|Frequency response and phase||Impedance||Frequency response under 0/ 30/ 60°|
|Distortion for 90 dB||Step response||Wasterfall|
The little box for the W 22 NY 001 did not just need to be compact; it needed to be significantly smaller than 35 liters. When I said that 5/7 of that volume would do it, Hermann nodded at the other end of the telephone line, so I went ahead and had the wood cut to size at the hardware store. To add a little bit of color to my pictures, I used black MDF for the interior boards; I had beech multiplex cut to size for the sides. At this point, I’m no longer worried about cracks in the woodwork. A bigger problem is glued wood’s tendency to bend when it is only painted or oiled on one side. A milled groove all the way around helps to prevent that, by providing a larger gluing surface in two directions. I captured the creation and assembly process of the boxes in photos.
Cross over network
Separating loudspeakers close to their limits requires more than just one or two components per branch in order to create the right addition. Here, third-order filters were needed for both chassis elements just so they could hit the same notes in even a small range. For the W 22 NY 001, I also needed to compensate for the peak between 300 and 2000 Hz, which involved three more components in a suction circuit. I ignored the narrow dip around 850 Hz, probably caused by the membrane suspension and accepted by the chassis builder as a compromise for other benefits. I was able to skip a volume adjustment for the tweeter using a voltage divider. Its connection pulls it down to the level above 10 kHz, which is around 88 dB. The addition of the branches is fault-free if the bass and tweeter are connected out of phase..
At 88 dB of sound pressure and given the tonal standards I set for my Excel 22 DXT, smoothing the impedance for tube listeners was a basic requirement.
A common follow-up question from our do-it-yourselfers relates to building the crossover, which I like to glue to a wooden board. In this case it has two parts, so I took a picture to provide an easier explanation.
The last part of the documentation is also essential: installing the components in the cabinet.
Once they were assembled, I was able to measure the boxes as a finished product.
|Frequency response and phase||Impedance||Frequency response under 0/ 30/ 60°|
|Dsitortion for 90 dB||Step responce||Watefall|
When the boxes were finished, I called Hermann. He came right away, bringing Doris and a few records with him for a listening test. It was a good thing I had just set up a new little treasure in the store – two days earlier, Walter Fuchs had installed my Benz system with his best technical competency and measuring equipment. My new turntable was called “Destiny Incantare” – Thorsten Langer gave it to me in anticipation of my retirement, hopefully 20 years too early.
We started with Neil Young’s “Harvest,” an album that is being reissued soon on vinyl, in an old-style design with rough cardboard on the outside and a glossy interior along with hand-written printed texts. The artist himself does not demonize the CD, but he does say that the small atmospheric sounds are reproduced more delicately on record. A good test of this was “Heart of Gold,” which confirmed the singer’s statement in a comparison with the silver disc; at the same time, it confirmed the dynamic skills of the Excel 22 DXT, which are unique to the Blues class. Hermann was smiling, and Doris took notice. “Meddle” by Pink Floyd was the next disc. It started off very calmly with “Echoes,” its floating vibrations completely freed in the deep space, and then moved on to more rock-based elements. The listener sitting in the middle wasn’t the only one who enjoyed it. Clean basses, bone-dry and clearly drawn, rang out on “Telegraph Road,” since Dire Straits and Knopfler’s distinctive voice were essential to this trip down memory lane. The increase in tonal quality compared to the previous box, which was by no means bad, was clearly reflected on Hermann’s face. “Beautiful!” said Doris, moved, when she heard Pavarotti sing “Nessun Dorma” as if it were the easiest thing in the world. No, we didn’t miss the mid-range speaker. The bass and tweeter had come together as a harmonic unit that didn’t need a third party.
When Doris and Hermann said their goodbyes a couple of hours later, they were both beaming. They had found a compromise between box size and space constraints that made them both happy. “Of course, I would have let him build some big boxes too if the little ones didn’t work,” Doris said to me as they left.
Technology Excel 22 DXT
|Chassis||Excel W 22 NY 001||Wood list in 19 mm MDF:|
|Seas 27TBCD/ GB-DXT|
|46,0 x 30,0 (2x) sides|
|Sales||Intertechnik||46,0 x 23,0 (2x) front/back wall|
|Construction||Udo Wohlgemuth||26,2 x 23,0 (2x) lid/floor|
|Principle:||Bass reflex||Milling depth:|
|Nominal impedance:||8 Ohm||Bass: 5 mm|
|Damping:||2 bags Sonofil||Tweeter: 6 mm|
|Approx. cost per Box:|
|Assembling kit:||326 EUR 340 USD||Wood cut: 15 EUR 20 USD|
In case you want to build this kit by yourself all components are available from Intertechnik.