Fertin project - calling all open baffle experts

[Oz_Audio]

I have just read this thread and I am fasinated with this speaker!

bcherry, what are the dimensions of your "Golden Ratio" open baffle?

Also, could someone please post any links to 'Black Forrest' or any other info on the Fertin.

As I understend the 20ex, it needs separate power supply, is this 240/250v and would a 55watt AKSA be OK to drive them?

I have built a single Linkwitz Peerless 830500 woofa and intergrated this very sucessfully with my TLb's. I think this would integrate well with this speaker. Comments?

Mark

[fdegrove]

Hi,

BLACKFOREST

The AKSA would drive these with ample reserve.

Mark,

Brian is off to an audio show in Guangzhou so he may not respond for a while.

Cheers,

[dice45]

All,
tonite i inserted polarity reversing switches into my speaker cables. To be able to change absolute polarity on my Fertins.

Sonic deterioation caused by the switch is negliglible if present at all at this signal current level. But sonic difference between right and wrong absolute polarity is night and day.

[fdegrove]

Hello,

Detecting absolute phase inversion on dipoles or open baffle speakers is not easy at all.

IMHO polarity switching should be done at preamp level.
It won't hurt to know the absolute phase behaviour from first to last stage in the amplifying chain either.

Be aware that any single amplifying stage WILL invert absolute phase.

Ciao,

[dice45]

Frank,
methinks this is scaretalk. Preventing the folks from trying it out themselves, weaving a fog of mystery around something which is very easy to try it out themselves.

I happen to have a dipole and i had a guest tonite and we both agreed it was night and day.

Tell me, is this habit of yours to have the last word on any topic your are participating in, is this compulsive?
I observed lately that in the forums boards your are active in, your name shows up as last poster in 8-9 out of 10 posts. And in few cases this last word was a valuable contribution to the topic.
I remember during your timeout i gave you hints more than once to either contribute constructuve stuff or stay shut.
It is clearly observable you are not feeling even faintly inclined to take that hint serious.

-----------
Bernhard

[Peter Daniel]

I also tried reversing polarity on my open baffle dipoles, and indeed it's night and day.

[planet10]

Originally posted by fdegrove
IMHO polarity switching should be done at preamp level.
It won't hurt to know the absolute phase behaviour from first to last stage in the amplifying chain either.

Be aware that any single amplifying stage WILL invert absolute phase.

With more or less random absolute phase on the recording, it doesn't matter where you flip the phase and knowing what your system does to the absolute phase is unimportant since the only way to judge is to listen to the cut (some records will change abs phase from song to song) both ways and choose which way sounds best. Of course some multi-track recordings will have different abs phase from track-to-track and in that case it will be a hopeless task.

dave

[Variac]

here is a group that sells Supravox that popped up on another thread. Thought you guys might be interested

http://www.audiokit.it/ITAENG/Altopa...x/SupraVox.htm

Supravox seems to make field coil drivers too. One with Silver wire!! I think they are a lot cheaper than Fertin. Any good? I don't know, do you?

I must say Frank seems to have mentioned them at a very appropriate time.

[dice45]

Dave,
agreed, absolute phase changes from album 2 album if not from track 2 track.

I started yesterday to paint "+" and "-" signs on albums as Allen Wright does it, well, i do it on inner sleeves where i do a lot of other marking too. It is easy to listen for the changes (no, i am not giving hints, not gonna spoonfeeding y'all, you folks listen yourselves) and once one has settled on a choice (after a bit of practising done within seconds)

I settled on a record i got marked from Allen (+) and (i did not expect it other than that) with my Huber amplifiers haveing the polarity unchanged, i.e. (+), the record played better. So Allen and me have the same basis for abolute polarity now and could exchange marked records and be sure the other person can use the marking without thinking. Allen, thank you for showing me this!

For a multitrack recording with phase behaviours messed up, it's pointless and not worth the hassle.
For a track2track changing of absolute phase, well, the list on the sleeve on becomes longer.

Mark,
if you go thru this thread, you will find derogatory remarks on Supravox' QC. This has not changed, this rather has become worse, so JeanMichel LeCleac'h informed a few weeks ago when we met.
Yes, i knew that Supravox has a fieldcoil driver version of his 215-2000. AlNiCo and FC cost the same, about Euro 1000 a per piece. Both have the same manufacturing quality problems.
Compared to the outstanding manufacturing quality of the Fertin, this was no Q to me. I am not wealthy, i couldn't have afforded the Fertin after i tried the Supravox and .. e.g. the FC motor came off. I knew about their problems before and said to myself "well you are not going to find out the hard way about Supravox QC rumours"

I have read few report about Supravox. One guy on Melhuish's FR forum reported he had treated the cone with Ennemoser C37 and regretted it; he was asking who would like to buy them. On QQ why he did it he said that he thought there must be more to win. No further comment except that hmmmh, a thing having sonics like my Fertins noone dares to endeavour treatments to improve-worsen the sonics out of fear to destroy it and apart from that, the Fertin's sonics do not create any inner urge to do so.
I have heard from others that the Supravox is fine as midrange but needs a tweeter. It has outstanding spec parameters, considerably better than the Fertin. The Fertin however needs no tweeter.

Fertin/BlackForest:
I looked at the site yesterday and found he is charging close to 1000 Euro for a piece meanwhile. Yes, this is for his superspecially tweaked version.
Well, i presume i listened to that version (i paid about 750 Euro per piece) and he gave me the tweaking kit. No, i am not volunteering the tweaks, i promised him.
But what i can tell is that his drivers had about 50hours on them and he had tweaked them already. My Fertins had a very long break-in phase, they became better and better and better. 300hours is not enough. So judge yourself if the tweak was rashly done.
For the record, Kühn from Black Forest is utterly honest business-wise, no problem to expect if you order from him.

[fdegrove]

Hi David,

With more or less random absolute phase on the recording, it doesn't matter where you flip the phase and knowing what your system does to the absolute phase is unimportant

When one uses recordings as professional demo material it is important to know whether the marked plus is really a plus and the minus a minus.
Recordings with a variety of tracks taken from different tapes may show a lot of variety as far as absolute phase goes.
IMO,and at least to me,knowing wheter my own system respects or inverts absolute phease is important.
Imagine the situation where you carefully test a collection of recordings for phase correctness and marked them accordingly only to find out that the system used is phase inverting?
Bummer!

Also I mentioned this since quite a few systems nowadays use a single amplifying stage as a preamp and this is always going to invert absolute phase from the source.

Bernhard,

Keep in mind when using a switch at the output terminals of an amplifier, as you do, you may come across both solid state and tube amplifiers that do not appreciate getting an input signal and being deprived from a load at the same time.
Your switch has the potential of frying OPT or outputbank of the amp.
When I said that phase inversion is harder to detect on dipoles such as yours and especially ESLs I know exactly what I'm saying.
And if you think a little bit about it you will soon see why.

All,

So other than for safety reasons there is another reason to do absolute phase inversion at preamp level:

First of all it is much easier to operate from close by than to get out of the chair and reverse phase,get back to the chair again and listen again and so on.

Secondly since the amp is going to amplify the difference between absolute and inverted phase it makes it all the more easy to detect.

Good tools for determining phase correctness are Cheskys' test record (CD) and Ortophons vinyl test record.
Both of which are invaluable for setting up a system correctly.

There is much more to be said about this and for those interested
in the topic there is a lot of info available on the web.

Cheers,