[kevin gilmore]

if someone wants to send me pictures detailed enough to read the values of the signature, its a matter
of minutes to do the schematic. I have the rest of it done. Its the same as the other 2.

 

[davidsh]

Will these pcitures suffice?
http://www.head-fi.org/g/a/754837/stax-ed-1-signature-diffusfield-eq-extremly-rare/

 

[kevin gilmore]

nope. I think I already have better pictures than that.
 
I need extreme high resolution closeups of the circuit board, both sides.
or someone that can read the resistor values on all the resistors
on the back side, the values of the pots, and all the caps on the front side.
 
This is the same schematic as the ed1 with 2 of the filters removed
and different values for the remaining filters.
 
The resistors may in fact be the same, hard to tell, the capacitors are
definitely different.

 

[MLudovic]

Quote:

I have thought a bit about it and tested with a violin concerto. Don't really like those custom settings. The tonality is fairly nice, but the EQ'ing of the upper overtones of the violin makes it sound boxed in and slightly smeared, but on the other hand it makes for a more weighty sound than the original ED-1.
 
The original ED-1 sounds a bit more thin with 2 much upper mids in my opinion, but it has a nice sense of being at a venue with the instruments reverberating a bit and 'standing tall', and it does add some sense of spatiality. The problem with the music I heard can be that the sound is suddenly like being in a very big hall, but the instruments still retain the same characteristics as when they were recorded. Violin recorded up close sounding like it is very far away is not good and makes for a strange sound... it might work well with big orchestras and such, will maybe try that later.
I just think the instruments are too slim/thin, and the sound seems slightly grating and on the verge of being harsh, which is not nice.
 
I like the original ED-1 the best. I am using the lambda sig's. Overall I think I'd prefer the sound without the ED-1 emulation, as I think it can be a bit fatigueing.
 
Just some thoughts based on a listening session. The music used was 'La Stravaganza' performed by Rachel Podger.

 
Very interesting feedback, I share the same feeling towards the stock ED-1, bright and adds a lot of air to the music but may be too detailed and light sounding depending of the type of material. Definitively not for rock/heavy/metal stuff.
 
The custom curve is to me the best compromise between diffuse field Eq and taming the terrible hi-mid resonance that cripples the 404. It certainly suits my particular ear and my musical tastes, but it also sounds very close to my equalized speakers (JBL 4311) : "neutral" and not fatiguing even at high level.
Quote:

nope. I think I already have better pictures than that.
 
I need extreme high resolution closeups of the circuit board, both sides.
or someone that can read the resistor values on all the resistors
on the back side, the values of the pots, and all the caps on the front side.
 
This is the same schematic as the ed1 with 2 of the filters removed
and different values for the remaining filters.
 
The resistors may in fact be the same, hard to tell, the capacitors are
definitely different.

 
Kevin let me thank you for the schematics pdf I found on your website. I noticed very strange values on the ED-1 trimpots, could you elaborate on that ?
 
If only an ED-1 Signature owner with enough electronic skills could write us down the schematic, or even send a dirac pulse in it and record the output, we would eventually be able to close that case...

 

[Jonathan66100]

Hi everyone,
You think the ED-1 can operate fully with a no pro lambdas?
 
I would also say that the curve made ​​by MLudovic at a effect for me on the Sigma with convolver DSP, maybe because he has the driver of the first Lambdas and this curve was made for the Lambdas pro.
Anyway this curve ( for me ) reduces reverb, makes everything a little more natural and adds to a space between the instruments and enlarged thus the already large soundstage Sigma.

 

[milosz]

Don't these Stax unit do some frequency selective crossfading  (or crossblending  whatever you want to call it) as well? Does the FOOBAR plugin do this as well, or is the FOOBAR patch just the EQ?

 

[MLudovic]

No, the two channels are independent, but nothing prevents you from adding a crossfeed to the DSP chain.
 
 
 

One ED-1 channel

 

[Julez]

Hi Guys,
 
I had a audio measuring system during my bachelor thesis. So
I did measure the ED-1 Signature with a sine sweep test signal
and got the IR of the ED-1!
Here's a picture of the curve:
https://www.dropbox.com/s/l23dd03lqb4gly3/Stax%20ED-1%20Signature%2044.png?m
 

 
Here's a link to the IR Wav file for those how are interested:
https://www.dropbox.com/s/zzjbiqwn0nf23tw/Stax%20ED1%20Signature%20Diffusefield%20EQ%2044kHz%2016Bit%20256%20Samples.WAV
It was sampled in 44.1kHz at 24bit (cut down to 16bit) resolution and is 512 Samples long and it was only one channel taken from the measurement
to have identical IRs on each channel. Just use any convolver programm. It was cut to 2^9 Samples so it can be used with FFT directly.
For any questions please ask me!
I have the IR also in 48, 88.2, and 96kHz but not ready as wav. If anyone has the monkey forrest measurement system he could get the
spectral files to process them to an wav outputfile!
 
I hope this can help you all!
 
Regards Julez
 
PS: If someone could explain how to add pics to the text or include files to the post please let me know!

 

[Jonathan66100]

I am not a pro but Thank you Julez : )
I test as soon as my friend give me back my sigma.

 

[MLudovic]

And we have a winner 

 
That's exactly the type of data I've been looking for, and the good news is that the impulse can be used directly in the convolver plugin. It suits my SR-404 better than the Monitor curve btw.
 
Finding the schematic is only a matter of time now...
 
Thanks again Julian!

 

[Julez]

Just to make it clear:
As far as I understood the ED-1 is ONLY for the Lambda Pro. The ED_1 Signature can be used for all other
Lambda models including the x07 range. It is NOT suited for the Sigma as the Sigma has a totaly diffrent
frequency characteristic!
IMO the diffusefild EQ makes only sense for dummyhead recordings with a diffusefild compensated recording
technique as the Stax Kunstkopfaufnahmen. The ED-1 changes the frequency curve of the Lambda models
from direct-field to diffuse-field (have a look into theory of soundwave propagation for more details). It was not 
intended to use with normal recordings! And it is not a good alternative for a working digital virtual acoustic simulation
(or auralization). I think it sounds very bad with normal recordings! The diffusefield eqs where desinged for audio
engeneering. Not really for home use.

 

[MLudovic]

You're right saying that these boxes were designed with a specific use, since the amount of EQ they add is rather important, but they can sound surprisingly well with certain type of music (acoustic recordings, jazz, electro) by adding air and emphasising a range of high frequencies.
 
I was very curious to see and to ear what these mysterious boxes actually do to the signal, and studying their behaviour was very helpful to find the right EQ for my SR-404. Now I can do long listening sessions without getting the feel that a red hot nail is being slowly introduced in my ears 

 

[davidsh]

^Still, amazing you chimed in... The ED-1 is made for the lambda sigs afaik? Anyway, are you telling us the ED boxes are only good with binaural music that is recorded with diffues field eq in mind? I'm sad to hear that..

 

[Jonathan66100]

Hi All,
 
@ Julez.
 
Yes i know about ED-1 Monitor and Sigma but i say more up 
"I would also say that the curve made ​​by MLudovic ( based on the shematic of the ED-1 Monitor ) at a effect for me on the Sigma with convolver DSP, maybe because he has the driver of the first Lambdas and this curve was made for the Lambdas pro.Anyway this curve ( for me ) reduces reverb, makes everything a little more natural and adds to a space between the instruments and enlarged thus the already large soundstage Sigma."
while it has no effect on my 207.
 
if the curve of ED-1 Signature was made for all Lambdas, I'll try tonight with my 207 and I'll tell you what I think with the STAX CD BINAURAL and on the normal CD music.
 
@Davidsh
 
Yes if it's this the case,  it is really shame that the ED-1  was realized only for Binaural CD : /
 
@MLudovic
 
Hi : ) 
On my Sigma the curve of the ED-1 Monitor adding air too but no effect with my 207.
 
 
Anyway thank Julez for your curve of ED-1 Signature !

 

[MLudovic]

Here are the impulses for the 3 Stax boxes and my SR-404 custom :
 
http://www.petit-fichier.fr/2013/09/02/stax-ed-1-monitor/
http://www.petit-fichier.fr/2013/09/02/stax-ed-1-signature/
http://www.petit-fichier.fr/2013/09/02/stax-ed-5/
http://www.petit-fichier.fr/2013/09/02/stax-sr-404/
 
 
I'll try making custom curves for other Stax models by working on their frequency response measurements...