SEAS CNO-T25
Copyright 2010 Troels Gravesen

CROSSOVER     CABINET      MEASUREMENTS     CNO-T25 KIT 


Download data sheets:
W18NX001 + T25C003  or T25CF001

Based on response from the CNO construction, a few people think the T29 tweeter prices are a bit steep - and they are indeed, thus this T25C003/T25CF001 version. The obvious question is: How much better are the T29 versions? Hmm....that is a tough one. I do think the T29s are better, but if I had to pick either in a blind test, I'd probably be in trouble. If I had to point out some difference, it might be that the T29s are better handling large sound volumes, i.e. they can play louder before compression. At moderate listening levels, the differences are more subtle.
I won't do a lot of writing on this one. For more comments on drivers and construction, please read
CNO mkII article.


Crossover
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Crossover schematics.

The crossover in many ways resemble the CNO, being a series construction - and including some modest equalisation to the midband. This caused some controversy with the CNO and I strongly disagree the equalisation "kills the sound". It is very easy to fool the ear (our brain) by rising a specific frequency band that will spew out details - if the musical source allows - but basically it's low-fi and not how the reproduction was meant to be.


Crossover components
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Crossover components + drivers from
Jantzen Audio

Contact
contact@jantzen-audio.com

Download Kit Sales Presentation here.

All kit and component prices may be subject to change and are always to be confirmed by Jantzen Audio Denmark.


Please all technical question at troels.gravesen@hotmail.com


Cabinet
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Make cabinet from 19-21 mm panels and front panel from 29-21 mm laminated panels.
Make base plate to tilt cabinet 5 deg. Click image to download drawing.
Port is the same as for CNO mkII, 68 x 150 mm.


CNO-T25 testcabs. 2 x 16 mm MDF laminated for front panels.
Remember to chamfer W18 driver hole well for proper rear ventilation!


Measurements
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Left: SPL @ 1 meter/2.8 volts. System sensitivity = 85 dB/2.8 volts.
Right: Blue = tweeter with inverted polarity. Point of crossover = 2700 Hz.


Left: Impact of mid notch filter. Right: System impedance, minimum = 6 ohms.


Left: CSD/40dB. Right: CSD/20dB

 

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