A26 frequency response and impedance response graph

A26 cabinet with vintage white grill cover

Seas A26 10" 2-way Kit PAIR (based on the classic A25)

Manufacturer: Seas Prestige

6 Customer Review(s)

Product ID: A26 Kit Pair

$1,239.00

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Seas A26 10" 2-way Kit Pair - a new spin on a true classic!

Price is for a PAIR and includes a 10% discount on all parts.

Designed by Håvard Sollien & Diego Ivars at the SEAS R&D laboratory.

Seas of Norway and Madisound are excited to provide the A26 speaker kit. This kit utilizes the A26RE4 10" classic paper cone woofer and new T35C-002 1.5" textile dome Excel line tweeter, in a 1 cubic foot aperiodic enclosure (12 3/16" W x 20 1/16" T x 10 1/4" D).

Carefully designed drivers with complementary response characteristics allow for a crossover network using only two components. The classic 10" paper cone woofer is run full range and the tweeter is rolled off by a capacitor. The 10 ohm resistor can be adjusted to meet your listening preferences. We suggest using a bi-wire cup so that you can make the resistor adjustment outside of the cabinet, using the resistor as the jumper to the tweeter (-) terminal. 3 different resistor values are included with the kit.

After spending several days with the A26 during its debut at the Rocky Mountain Audio Fest and later at Axpona in Chicago, we fell in love with the speaker. It has a very warm and comfortable sound, as you would expect from a driver combination like this. It is actually pretty true to the sound from the original A25, but with much better highs and slightly more dynamic overall presentation. The 1.5" dome Excel tweeter has no problem with the simple slope and low crossover point. Although people often talk about the extended highs of tweeters, often beyond the audible listening range, the true magic occurs in the lower frequencies and this tweeter excels in that range.

The aperiodic loaded woofer and excellent roll off on the low end of the tweeter has resulted in a speaker with very good transient response. Pure, simple, and elegant.

Link to Seas A26 Application Notes

Each A26 Speaker Kit Includes:

(2) Seas Prestige A26RE4 10" Classic Paper Cone Woofer
(2) Seas Excel T35C-002 1.5" Textile Dome Tweeter
(2) Mundorf M-Cap Supreme 3.3 mfd Capacitor
(6) Mundorf M-Resist MOX Resistors - 8.2, 10.0, & 12 ohm
(0.22 lb) Acousta-Stuf - 0.11 lb fluffed and filled in each cabinet
(2) Acoustic Foam Piece for Aperiodic Vent
(20) OXSOCKET8X1 Socket Head Wood Screws
(7 ft) Supra Classic 1.6 Internal Hookup Wire - 18" for woofer, 22" for tweeter
(8) QC205 Quick Connects
(4) WBT Copper Crimp Sleeves - for installing cap in + line of tweeter
(1) Acoustic Foam Sheet - line internal walls of cabinet
(1) Wool Felt piece - line rear wall of cabinet
(8ft) Foam Tape - for airtight seal of drivers to baffle

Optional Items From Drop Down Menus:

(2) Pre-finished Cherry Cabinets (as pictured) w/ TD-CUP input cups included
(2) Input Cups - or - (4) Binding Posts - if not purchasing cabinets
Alternative Capacitor Options

All kit pricing shown includes at least a 10% discount on all drivers, parts, and cabinets!

Beautifully Simple Crossover Network

For the kit we use the Mundorf Supreme capacitor for its low distortion and musicality.

The crossover closely follows the original A25 design, and is a model of simplicity. The use of linear drivers with complementary roll off characteristics allows for excellent performance without the need for complex filter networks. The well behaved roll off of the woofer’s paper cone, aided by the four layer voice coil, allows it to be connected directly to the amplifier, just as in the original. The tweeter is easily matched to the woofer using a first order network; consisting of a single capacitor (3.3μF), along with a series resistor (10) for level matching. The resistor value can be adjusted to fine tune the tweeter level (12, 10 or 8.2).

Tweeter Level Options

We recommend using the the TD-CUP dual binding post input cup for ease of tweeter level adjustment. Wire the tweeter to the top set and the woofer to the bottom set. Remove the (-) strap between the top and bottom binding posts, and insert the resistor in its place, and tighten down the binding posts. This will allow you to swap resistor values to taste without having to open up the cabinet to make those changes. Run your speaker wire from the amplifer to the bottom set of binding posts.

Seas Prestige A26RE4 Woofer

A classical paper cone and matching natural rubber surround produce a smooth response and reduces potential resonance problems.
A four layer voice coil provides a well behaved roll off characteristic.
The magnet system has a T-shaped cross section of the pole piece for low modulation distortion.
Extremely stiff and stable injection moulded metal basket keeps the critical components in perfect alignment. Large windows in the basket both above and below the spider reduce sound reflection, air flow noise and cavity resonance to a minimum.

Woofer Curve

Seas Excel T35C-002 Tweeter

The T35C002 is a classic dome midrange tweeter with high sensitivity and a smooth, extended frequency response.
A coated fabric dome with integral surround manufactured by Dr. K. Müller in Germany ensures excellent performance and consistency. This supplier was among the first in the world to offer fabric dome diaphragms, and did produce the diaphragm for the famous 1.5” Dome Tweeter H087, developed by Seas in 1968 for the Dynaco A25 speaker.
A small, high efficiency Neodymium ring magnet in a carefully designed system contributes to high sensitivity and low distortion. The top plate and T-yoke are CNC machined for excellent precision. A well damped vented pole and a rigid rear chamber ensure a low resonance frequency and smooth response.
A generously underhung 35mm voice coil wound from copper-clad aluminum wire further enhances the sensitivity. Flexible lead-out wires and venting holes in the aluminum coil former help reduce noise to a minimum.
A 7 mm thick precision machined aluminum front plate with moderate horn loading ensures linear frequency response and represents an extremely stable platform for the magnet system and the moving parts.

Tweeter Curve

The Enclosure Design and Stuffing

The SEAS A26 loudspeaker is based on a 28-liter cabinet. Position of the drivers and dimensions of the cabinet walls and vent opening are all very similar to those of the original Dynaco A25. For best performance, these dimensions should be followed closely. Adding internal bracing to stiffen the cabinet is a good idea for the advanced builder, and will further enhance the performance.

The cabinet stuffing (50g) is distributed evenly inside the box. The highly damped vent acts as an acoustic resistor, resulting in a non-resonant (aperiodic) system. The quantity of polyfill stuffing used in the vent is 12 grams. We suggest mounting a piece of screening material over both sides of the vent to hold the stuffing in place. Decreasing the vent stuffing will improve the time response of the bass system, but will lower the bass output due to the lowered Q. If, on the contrary, more polyfill stuffing is used, the enclosure will behave closer to a sealed box and a higher Q will be obtained. However, the time response will be slightly deteriorated. We find 12 grams of polyfill to achieve the best balance between the time and frequency performance of the bass system. This amount of stuffing is based on measurements and extensive listening tests. The result is a smooth, yet detailed reproduction where the entire frequency range is in balance. We encourage you to follow the above guidelines, but you may also try experimenting with the stuffing quantities yourself, to achieve your preferred bass performance. (Madisound uses a strip of acoustic foam instead of the fill, and the speaker measured and sounds the same. At the RMAF show designer Diego Ivers also agreed that it was perfectly fine to use this material. Kits that we provide will be sent with the foam as it is much easier to use.)

Madisound Fully Finished A26 Cabinets (optional)

The Madisound A26 Cabinets are made in the USA and constructed of high quality MDF and finished with a real cherry wood. The only side not veneered is the back, which features an attractive piano black finish. The front baffle is cut for precise flush mounting of both the woofer and tweeter. The back side is cut for a precise flush mount of the TD-CUP dual binding post input cup. Also included are removable magnetic grill covers finished with a retro style white grill cloth.

Cabinet Dimensions: 12 3/16" W x 20 1/16" T x 10 1/4" D

Link to cabinet plans in inches
Link to cabinet plans in metric

High quality birch flat pack cabinet are also available for purchase through Speaker Hardware.

Listening Room and Placement
High quality stands should be used to bring the tweeter approximately to ear level or slightly above. Even in the best listening room, it is important to determine the positions where the loudspeakers will perform optimally. Placing the cabinets too close to the walls or corners will result in more powerful bass, but may also cause response irregularities in the bass/midrange area. Some experimentation is recommended in order to find cabinet positions that result in a good tonal balance and freedom from coloration.

The tweeter diaphragm is relatively large for sensitivity reasons. Consequently, the highest frequencies are more directional, making it worthwhile to experiment with toe-in of the enclosures towards the listening position.

The SEAS A26 is a refined, yet simple and fun loudspeaker, meant for enjoying your music to its fullest!

Assembly Instructions & Tips

Clear you work space and lay everything out
Take note of the accessories packing list that came with your kit
Cut the foam sheet into the designated sizes and press fit, glue, or staple to internal walls
Cut the wool felt sheet in half, hand place on rear wall, trace rectangle cutout for input cup with sharpie on the felt from the rear of the cabinet
Cut out rectangle, glue or staple sheet to the rear wall
Cut the wire to length and strip the ends
Attach the tweeter wire to the top set of binding posts, crimp capacitor in the + line of headed to the tweeter
Attach the woofer wire to the bottom set of binding posts
Install input cup on back or cabinet and feed wires into the cabinet
Tease out the Acousta-Stuff, split in half, and insert half into each cabinet
Tease out the Acousta-Stuff and insert into cabinet
Attach wire to tweeter, tap pilot holes with drill, mount tweeter with included screws
Attach wire to woofer, tap pilot holes with drill, mount tweeter with included screws
Remove the (-) strap between the top and bottom binding posts, and insert the resistor in its place, then tighten down the binding posts
Attach speaker wire from your amplifier to the bottom set of binding posts
Done, enjoy!

6 Customer Review(s)

Trip Back to the 60''s

Reviewed by adydula on 07/18/2023

Gosh Dynaco A25's when I was growing up were a really neat speaker with thousands and thousands of them built and sold. For some reason I missed this gem of a speaker. Well move forward in time and Seas has made a new version of this 2 way Dave Hafler design available with updated drivers! Seas A26.

I have owned many speakers over the years, from the $99 bookshelves to the $10K 180 lb floor standers. For the past few years, I noticed that a few vendors were offering this A26 design. Madison has the kit with all the new updated internals. Well, I finally bit the bullet and called Madsionsound and spoke to Josh and ordered the entire kit. Yes the price has risen but what hasn't lately! After a few questions we placed the order and included the Cherry cabinets built by John up in Conn. I also selected to top of the line Mundorf EVO Silver/Gold/Oil caps. Well worth the expense.

I no longer have the tools to make cabinets, so this was a quick way to get up and running. Well made, SOLID, nice Cherry Veneer, all openings cut out precisely to fit all the drivers and rear panel connection assembly. I asked John about additional bracing as mentioned in the SEAS application notes, and with his 30 years of building speakers did not think this was needed and if not done correctly could cause more issues. When I got the cabinets, there is no need for bracing imo. Solid, well built. Cabinets add $599 to the just north of $1200 for the internals.

Started at 8:30am and had sound tests at 3:30pm. Drilled pilot holes for the drivers and connection assembly. Cut all the foam panels for top/bottom and sides. Not enough foam for the back panel. A call to Adam and he sent me a supply of 1/4 wool felt for the rear panel. I used Loctite spray adhesive for all the damping.

I choose the 10 ohm resistor, soldered it all up. Used the slip on connectors. The ones on the tweeter were very tight and had to open up the connectors just a tad. All nice and tight, snug...no need for soldering. But if your anal go for it...just be careful.

If your mechanically inclined and can work with hand tools, this is an easy DIY project. Just take your time and think things through. You dont want to put a screwdriver through a speaker cone!

I used the foam for the front bottom slot instead of the 12 grams of polyfill.

I took the bag of acoustic filling and split it into 2 equal parts and weighed it...right around .11 lbs or 50 grams. I pulled it apart and placed behind the woofer area...with the internal wiring its easily suspended.

Did a sound test. Went well. Removed the drivers and applied the speaker gasket material re-installed and put on the soft feet.

Sound. One Word EXCELLENT. These speakers are just made for Acoustic material....I use a Van Alstine Ultravalve tube amp...the great granddaughter of the Dynaco ST amps...absolutely wonderful pairing.

Good ole Jazz at the Pawnshop...Limehouse Blues was superb..These are not bass monster but hey it doesn't have a dedicated woofer, its a mid-woofer!
A simple but elegant 2 way design that just works so well.

Very clean clear crisp sound, Wonderful airy presentation in my listening room, slight tow in. Have them on 24" sand damped stands. Dave Grusin's Sticks and Stones material will amaze you with how these 26's reproduce bass and sharp Strataco sounds, drums and the like. Piano, guitars sound so natural and "right".

In the end I wish I bought these years ago, but these are supposed to be even better than the original design. I highly recommend this kit and the folks at Madisonsound were nice and helpful. Great folks to deal with.

Ok...back to re-listening to my music collection, its all new again!! Dont wait! Life is short....

Alex

Easy Awesome

Reviewed by deuceadam on 04/08/2021

WOW, very easy build these speakers are so well matched. I haven't even broken them in and they sound great. I disagree with the tow in for staging I built these for my wife's vinyl-only system and put on Grover Washington live we hear a symbol coming out of the left channel we both stare at it then suddenly directly in front of us right above our heads we hear the guitar and sax we both look up in shock almost scary as if we are in front of the stage.

We are using a Denon 450 turntable and a Denon 3805 AVR receiver

Verified Purchase

Search is over

Reviewed by waterclocker on 06/29/2018

With as much praise as the original vintage Dynaco A25 get, I knew I had to hunt down a pair. The challenge of hunting down a pristine pair set in after seeing many listings for overpriced and poor condition examples. Not to mention them arriving safely if not found locally. In comes the A26. I came across this kit in my many searches and researched it's performance in popular DIY audio forums.

I decided to go the easy route and purchase the cabinets also. This made the build a snap and they are very well made. I had a small cosmetic issue with one of the drivers and Madisound was quick to make things right. They were also very helpful with clarification on the assembly. I would recommend picking up a tube of Goop to secure the foam inside and soldering the wires inside vs using the crimp on clips.

On to their performance! These have easily outclassed my other vintage speakers! The included tweeter really steals the show with the Mundorf Gold/Silver/Oil option. Any source is accurately represented and upstream changes in gear are very noticeable. They do not sound harsh or bright unless your gear is tuned that way. I love their sound with my Inspire KT-150 Hotrod tube amp, sweet sounding and very realistic clarity. Probably not the ideal match for a single ended tube amp, but the results are impressive in a smaller room with enough bass for most recordings. Pairing them with my Pioneer SX-980 worked nicely in a larger room and they benefit from the extra power with more low end slam. Anyone looking for a vintage style speaker with high end sound should not pass up this kit!

My only minor complaints would be the fabric grills and the spade connectors. The grills look really nice, but they affect the clarity of the sound. The material used is not as acoustically transparent as I would like, but you would probably run into the same issue on various vintage speakers anyway. They are easily removed and the speakers look great without them. The spade connectors didn't seem to fit well on all the connections. The speaker terminal cup mainly. No big deal though, I would rather solder my connections anyway. They could be a little fiddly if you are trying to build without soldering. All in all though, the quality and performance overshadows these issues. Highly recommended and I look forward to ordering from Madisound again!!

Verified Purchase

Happy

Reviewed by rkuimelis on 01/25/2018

Long overdue feedback. Very happy with the SEAS A26. Use them daily as my main speakers. They work especially well with my First Watt diy Class A amps (M2 and VFET). Fun speaker that does most things well. Nice tweeter. Was expecting more low end from the large woofers, but things really came into balance after I rotated in the class A amps.

This was my first ground up build. I opted for some beefy internal bracing and surface damping. Build details here: http://www.diyaudio.com/forums/multi-way/301540-seas-a26-build.html

BK

Verified Purchase

Wide Boxes Sound Good

Reviewed by bdbender2 on 01/02/2015

Back in the day I had several ARs, a KLH, and I still have an Advent. Fate never brought one of the Dynacos my way although I thought the stuffed vent was intriguing.

I have been listening to skinny speakers for years: small Focals, SEAS Loki kits, Snell skinny towners. In 2012 I built some Eton S7s, and did a review here on Madisound that links to DIY Audio. I also have some Focal 918s at the moment.

The Focal 918s are really nice speakers, with molded asymmetrical cabinets and reall good drivers in them. I recently changed from tube amplification (back) to solid state, and the Focal tweeters didn't like it much. The S7s went back in the system, and the Focals went back in the shipping boxes and back out into the shed. (Surprised the heck out of me.)

I built the A26s with the Dynamat and the Mundorf fanciest "gold" tweeter. I soldered the input connections and did not bi-wire. Used the 10 ohm resistors. No photos for this build, it was really straightforward.

It took a couple of weeks to get used to the appearance of those fat speakers up on stands in my living room, and I ended up with shorter stands (EPOS ST15), but boy is the sound "out in the room". The larger tweeters just sound great. The S7s are back in their boxes, too, out in the shed.

I have been listening to some of the Blue Note reissues from Acoustic Sounds. I am of a certain age and can't hear much above about 8,000Hz any more, but I can say that well-recorded cymbals sound full and you can hear the shimmer. The saxophones, too, just sound wonderful. At the "audiophile" end of things, Shelby Lynne is all there, and so is Daft Punk. (Although I should point out that I am running self-equalizing subwoofers below about 46Hz.)

Be sure to check WAF, though. These fat tan obviously veneered things replaced skinny shiny piano black things in my house...

A True Dynaco A25 Clone

Reviewed by jgrabertmd@yahoo.com on 02/27/2014

I own several pairs of original Dynaco A25s. This new kit is as close to the originals than any other clone I have evaluated. They have a much better high frequency extension than the Dynacos however. Because of the this the clarity is better with better imaging while still maintaining the mid-range warmth. Do not go cheap on the capacitor or resistor. I recommend the mundorf silver/oil as it is the best band for the buck in this kit. The enclosures provided by madisound are gorgeous. I absolutely love the original A25s but the Seas A26 takes them to an entire new level.