SEAS FA22RCZ vs. Fostex FE206En

[Joachim Gerhard]

The easiest whould be to make a solution with Dammar in Spiritus. Put so much Dammar into the Spiritus until it is fully saturated. You can buy Dammar at the pharmacy. It is also used by artists to ground a painting. Use a small paint brush and coat it thin, wet in wet.
Wait for a day and coat it a second time. I did not use Dammar but a liquid polymer especially developped to coat membranes. I can not tell you the recipy. I buy it from a trusted source. I could imagine that you use a 2 component epoxy glue that does not dry too fast and thin it somewhat out. Try first your home made brew on old and cheep drivers. Gather experience. That is what i did. Also posible is a coat of Schellac. You can buy liquid Schellac for restoring historical furniture. You can also use violin laquer that is sold to intrument builders. I whould use a somewahrd hard variety. The trick seems to be that you stiffen and damp the wizzer so that it does not move caotically any more but more like one piece as a piston with a higher speed of sound then before. The peak and dipps come from out and in phase movement of the wizzer that interfer with the cone. It is a combfiltering effect.

[superlian]

And you cote the whole inner area of the wizzer, not the backside?

[Secips]

Originally Posted by simplymortified

Has anyone built an Aperiodic box? I am think of modding the sealed boxes with some home made 'variovents'.

Interesting driver. Keep us informed of your progress.

IME, what little there is of it , sealed and aperiodic designs work very well with FR speakers. I use Variovents, the Scanspeak version is still available. I prefer aperiodic designs as the enclosures are much smaller.

I find that you get better results using room acoustics (room gain) to get better bass. Furthermore, I find that bass produced by FR speakers "slow" or "wooly." I think that because its a point source that group delay effects becomes easily discernable, simply because it stands-out, even if group delay is within one cycle. FR speakers may require as little as a quarter wavelength.

[bluewater]

Hi Dave,

Have you had a chance to test the FA22RCZ's and maybe treat them.
Any comment's on the improvement?
I'm thinking about buying a pair and attempt to treat them my self after breaking them in. After reading the latest burning amp article I want to try Mr.Pass's nice and simple OB with the F2J.

Thanks,
Eric

Originally Posted by planet10

Got mine today. 1st impression: packaging is unimpressive. Some of these are probably going to get damaged inside the packing box.

Open spider is nice... looks like room to put substantial damping on the front face of the magnet behind the spider.

Cone has interesting strands of light coloured stuff in it.

Cone shape & wizzer look vintage.

dave

[planet10]

Originally Posted by bluewater

Have you had a chance to test the FA22RCZ's and maybe treat them.

No they are still sitting untouched... drivers that people have bought are keeping them down in the queue

dave

[tiefbassuebertr]

Originally Posted by steviedon

They won't be in direct competition until the seas has proven itself to be DIY friendly, and a few ambitious diyer's have experimented with it. With the 30hz FS it's not IMO in direct comparison with really any fullranger I'm aware of.

I agree. One can say, that the SEAS FA22RCZ is better suitable, if there is no possibility to add a subwoofer system. Thus I can operate down to the aera arround 30Hz (i. e. real full range operation in a closed or vented box) because fres is also 30 Hz and the linear excursion (X-max) is much larger than 0,8mm - the X-max from the Fostex FE206En.

If I use the Fostex FE206En in such an application, a high pass filter is necessary, even without the desire of an additional subwoofer. Nevertheless the highest possible output SP level is strongly limited. OTOH - the clearness and resoluition so as the dynamic behaviour of sonic quality is much more better in all respects (in opposite to the SEAS FA22RCZ) except inside the lowest frequencies.
by post #7 about
fostex FE206En
you will find a Boom-Box (Hoge BB-4) simulation example from me include high pass filter in front of the FE206EN.

What could therefore the reason?

I think, mainly the material of the surround. Rubber composition with good acoustical behaviour - i. e. low losses independend of the degree of excursions - is still a challenge. SEAS (actually DKM) has useful but not the best ingredients for their rubber surrounds. Thus the Qms value was and is still very low and the audible sonic quality - particularly the resolution - can not exceed a certain level, especially in the lowest level aera. Fostex prefer textil rubbers.

An additional shortcoming is the magnet by this Seas full range model (to weak BL product) compare to the Fostex.

If I start with both models a loudspeaker project include a subwoofer operation (x-over arround 70 Hz), one can say, that both transducers will enhance enormously the sonic quality in the midrange - high frequency aera, mainly because the X-max is significantly lower by the same SP levels at both models - but only in cases, if one chooses a BB-4 alignment include a correct designed high pass filter.

Nevertheless the Fostex has even in this filtered (satellite box) mode still a significantly enhanced audible resolution in opposite to the SEAS (and all the other full range drivers with rubber surround).

Here the pdf datasheet URLs:
http://www.seas.no/images/stories/pr..._datasheet.pdf
http://www.fostexinternational.com/d...df/FE206En.pdf

To investigate the exactly context in detail, I need an loudspeaker evaluation kit consisting of various magnets, spiders, cones (diaphragms) include voice coil, surrounds and baskets. I have seen such kits (special made for high end loudspeaker manufacturers) by a japanese supplier some years ago, unfortunately I can't find it in the moment.
Perhaps one of the members here can find the associate URL.