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Stax ED-1 and ED-5 EQs emulation - Page 5

post #61 of 71

Yes I just saw this, I will drop "head-acoustics"
In more must taken a HRTF of all channels 7.1, no only stéréo, therefore impossible to reproduce in Windows.

Therefore it is mandatory to have a "head-acoustic" box or the Smyth box for to use it fully the HRTF.

Edited by Jonathan66100 - 9/17/13 at 10:45am
post #62 of 71

Arnaud, this might interest you for your binaural recordings.


post #63 of 71
Originally Posted by Jonathan66100 View Post

Arnaud, this might interest you for your binaural recordings.

Thanks, been there and back already actually... Issue at the moment is to get my money back, not an easy thing with US businesses I have noticed...
post #64 of 71

Ha, it does not work well ?

post #65 of 71

It is theoreticly possible to use all very small microphones for recording the hrtfs.

But there are several issues to be handled. Small mics have a bad snr ratio.

I used two Sennheiser KE4-211-2 microphones. The snr is 55dB wich is good for

a small mic. It is electret and needs very(!) thin cable to fit into the ears with foam

to block the ear canal (and a battery and little circuit to energize).

I sugest for interested persons to read some papers or books about that matter

before starting. It depends on what one expects to do with the HRTFs.

Binaural simulations need very complex measurements and more complex

corrections to be simulated realisticly.

First problem is to present the needed sound incidence directions accurate enough.

That is essetial for later reproduction.

The Smyth Realizer works therefore with a headtracker and in ear mics to record

a set of HRTFs but with room information for exact reproduction of that specific

room for only this exact person. It measures also the FR of the used headphone

to invert that (or equalize the HRTFs whatever is done there). Again personalized.

Then you can feed a binaural renderer with the HRTFs and the actual orientation

(as done with the hardware box that has a binaural renderer inside). 

Static representation of the HRTFs is not very satisfying as I learned with my

properly recorded (horizontal) HRTFs. One confuses often front and back.

That can be overcome by headtracking. Nevertheless it makes the sound more

speaker like (or a bit like the Sigma but with clearer presentation).

If you want a static sim you can just record the left and right speaker seperatly and 

hold your head at exactly the same position and use that for left and right channel.

With more speakers it's clear what to do then.

post #66 of 71

Hi Julez

Thank you for your technical comments.


Have you ever tried Smyth?
To see if the effect of the head tracker is really convincing.

When I listen to a binaural recording like this.




I find the effect striking, even so it is not registered with my head.


I me said at the same time it's a shame to spend 3000 euro in Smyth  whereas if the sound engineers recorded directly binaural it would cost us nothing.


You compare the binaural effect at the sigma.
I admit that the sigma really gives me the impression of "out of the head" except for the sounds from the rear, which is a shame for video games.


The sounds rear left and the sounds rear right is very well represented.


So I wonder if spending 3000 euros for Smyth is reasonable, just for the reproduction of sound back.

Edited by Jonathan66100 - 9/19/13 at 5:25am
post #67 of 71
Thread Starter 

First post edited with the correct impulses!


Reading your discussion about HRTF is very informative, but to make a personalized set of impulses one doesn't need a perfectly flat speaker as a source ?


Sigma EQ curve to come. I'll also make an impulse from the Head "subjective filter", just because I can't help myself from converting the curve to a .wav... :D



post #68 of 71

Perfectly flat speakers don't exist!

But as flat as you can get is good. If you have some peaks and dips

this meens that in the dip frequency areas there is a worse snr than

at the flat parts and peaks. That's it. The FR of the speakers will be

removed by the reference measurement. So it will be perfectly flat

after treating the HRTF measurements with the reference measurement.

Remember when you divide every HRTF measurement through the

reference youll get only the difference between the measurement

with and without a person and therefore only the differences that a

head in the soundfield causes compared to a soundfield without a 

human head (and that is what you want to measure)!

post #69 of 71
Thread Starter 

Ok I understand, that totally makes sense. I guess bass response is still a tricky part to manage, how low do you go when you measure a HRTF btw ?


Here is the "Subjective Filtre" impulse : http://www.petit-fichier.fr/2013/09/29/head/

Not a very spectacular EQ, but adds a bit of warmth and thickness.

post #70 of 71

Bass doesn't matter too much when it comes to HRTFs anyway AFAIK.

post #71 of 71

For all people interessted in HRTFs a very good basic paper:




Have fun!

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