Seas Idunn 2 Way Loudspeaker Kit
The Idunn is a 2way High end Speaker kit from the Seas prestige range. It utilizes a 20litre, bass reflex cabinet which is ideal for small to medium sized rooms. The Idunn was designed by the R&D team at Seas, Norway and utilizes to optimally shaped drivers for high end performance and power. For a full description of the Idunn kit, we recommend you visit the Seas website here.
Seas Idunn Drive units:
The Tweeter utilizes in the Idunn is the Seas Prestige 27TBCD/DXT tweeter which incorporates a aluminium/magnesium alloy dome and an optimally shaped SONOMEX Surround which ensures excellent performance and consistency.
The Woofer choosen for the Idunn is the Seas Prestige U18RNX/P which is a fairly new driver from seas. This woofer is a 6.5" high fidelity woofer with an injection molded metal chassis along with a new CURV Cone System which incorporates a woven polypropylene cone, offering a smooth extended frequency response.
Seas Idunn Crossover:
The Idunn kit crossover is symmetrical with a 2.2kHz crossover frequency. The Idunn crossover point was chosen so that the directivity of the drivers make the overall power response extremely smooth, as can be seen in the measurements. Complexity of the crossover was held as low as possible witout sacrifising any of the audible perfomance. This is possible to achieve, because of the drivers very smooth response. On the woofer there is a simple 2nd order network, and on the tweeter there is a equally simple 3rd order network and an L-pad to trim the tweeter sensitivity. Together they align the phase of the drivers excellent and a gives a smooth interdriver transition. The rolloff of the drivers is steep enough to alow them to work effortless even at high power levels, thus maintaing the smooth and detailed sound quality at all levels and allowing them to be as dynamic as possible.
Seas Idunn Cabinet:
The Seas Idunn speaker is based on a standard 20 litre vented cabinet. This cabinet was chosen to give people an easy start to building a loudspeaker. See PDF file for cabinet drawings. Ask your local loudspeaker dealer if he can help you obtain this, if your not thinking of building it yourself. The important thing to remember when you are building this, is to keep the baffle width and internal volume of the original enclosure. Adding braces to stiffen the Idunn cabinet is a good tip for the advanced builder to take the loudspeaker just a little bit further. For cutting the holes for the Idunn drivers and port, may we recommended the range of jasper circle jigs.
Seas Idunn Cabinet Stuffing:
The amount of stuffing and port tuning for the IDUNN is based on measurements and extensive listening. The cabinet is filled with 250 g of stuffing. The stuffing is distributed evenly in the box, but kept away from the port openingto allow free movement of air. This is to ensure that the air flow noise stays as low as possible. The port length is 16 cm including the flanged end and the inner diameter is 5 cm. This gives a port tuning of 38 Hz providing a smooth low frequency roll-off.
Seas Idunn Kit Contents:
The crossover components utilized are and Audyn Cap QS Capacitors. Capacitor types are polypropylene. Inductors are Intertechnik along with the wirewound resistors. The crossover kit also includes a universal Crossover board to mount and connect the components. We can, on request, assemble the crossover for you are unsure of the schematic design.
Please note that the crossover pictured in the product photo is the deluxe version which utilizes 1.4mm intertechnik inductors and audyn cap plus and kpsn capacitors which are available on request for additional cost.
Jantzen Audio Crossover Option. Please when ordering, leave a comment to indicate you would like this version. No extra charge.
Seas Idunn Kit Accessories Package:
The accessories addon package for the IDUNN is for those who donot have their own supply of parts needed to complete this build. The accessories package can be selected from the drop down tab below. The accessories included are:
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Internal Crossover cabling. Intertechnik crossover cabling. OFC cable sourced from Germany.
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1.1pound of acousta stuf - loose and fluffy is recommended. Do not block the port.
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Driver surround foam tape - To ensure an air tight fit around drivers.
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Tweeter and Woofer Insulated Terminals - For driver tabs
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Driver Mounting Screws with T nuts - 8pair.
Comment from Seas on the Seas Idunn Speaker Kit
"The Idunn is one of my favorite loudspeakers, and they have been anchored in my living room for a long time now. It has a very neutral and detailed sound, but is still lively enough to get your foot tapping and listen to music for hours. Although, what really separates the Idunn from other speakers, is the controlled wide dispersion. This makes it sound good even outside the sweet spot, when I’m lying in the sofa reading a book, or jumping around the living room."
Håvard Sollien, SEAS R&D Manager
Seas Idunn Kit Measurements:
The measurements are taken in free field at 1metre on tweeter axis. 
As seen in the figure the average sensitivity is 85dB and the response lies within ± 1.5dB. The black curve shows the response with the tweeter connected with opposite polarity. The deep and symmetrical notch, when the tweeter is connected with inverse polarity, shows that the drivers are in-phase across the whole crossover region.
The off-axis respons of the Idunn is shown above. Here we really see the beauty of the DXT tweeter. The power response is perfectly smooth throughout the entire frequency range even at 60 off-axis. This gives a huge sweet spot, while still allowing for pin-point imaging. It also keeps the tonal balance of the loudspeaker all over the listening room.
The figure below shows the 2nd and 3rd order harmonic distortion with an output of 96dB at 1m. The overall distortion is very low and makes the reproduced music very clean and without coloration.
Deluxe Crossover above. Standard below.
The Seas Idunn Speaker Kit from hasaudio. All prices exclude gst.  Download Idunn plans
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