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post #46 of 151
Quote:
Originally Posted by pachku View Post

My guess is that there will be things it does better than the O2, things it doesn't, and at the end some things will be listened to on the 009, others on the O2, others on the LCD-2, and so forth...


That would be disappointing - I hope the SR-009 is all-around better than the SR-007 and other headphones such as the HD800, HE-6 and LCD-2. If it turns out to be yet another high-end headphone which is good for some things but not others, and a good choice for some types of music but not others, then it wouldn't be worth the particularly high price in my opinion.

 

Needing a full arsenal of headphones and amps to cover different types of music is somewhat ridiculous in my view...

 

post #47 of 151
Quote:
Originally Posted by visualguy View Post

Needing a full arsenal of headphones and amps to cover different types of music is somewhat ridiculous in my view...


Agree 100%

 

post #48 of 151
Quote:
Originally Posted by pachku View Post

We'll see. The SR-009 is announced for a mid-April release, and the guy who sold it on ebay looks credible so far, so it shouldn't be more than 2-3 weeks. Had good experiences so far with shipping from Japan. I'll be able to run comparisons of the SR-009 against O2MK1 and HE60 on the BHSE as well as on the 007t - although the race will almost certainly be decided on the BHSE. According to 2nd hand rumours, the SR-009 has been heard on the BHSE and is said to sound great - proving that there ain't such a thing as too much power L3000.gif  My guess is that there will be things it does better than the O2, things it doesn't, and at the end some things will be listened to on the 009, others on the O2, others on the LCD-2, and so forth...


In regards to amplification, sometimes less is more you know? My d/a is an example. Also, stax seem to confirm that the new electrode is easier to drive, which corroborates with existing listening impressions out of 727.

If you can spring for / own a legendary amp like the bhse, all the power to you, i don't doubt the sr009 sounds marvelous out of it. But in some circles, simply asking for reconsidering the needs for so much reserve of power with the new electrode causes quite some stir... Almost as if there's big vented interest in not interfering with ongoing dyi project / non stax amp offerings... Could there be such thing, I can't imagine wink.gif.
post #49 of 151

If the sr-009 turns out to really non-require the same level of power, I can see the ges turning into a great bargin. Very exciting!

post #50 of 151
Have ordered one from sofmap yesterday. Hope I can get it at the same day of release and have my friend shipped to me.

Although it might not be as good as HE90 but currently HE90 is at a unreasonable high price level.

2 years ago one of my friend bought Aristaeus + HE90 (last batch production in good condition) + a few spare pairs of headband and earpad only for $9000

Currently 1 pair of HE90 will cost the same amount....too expensive I just do not want to pay for it so I choose SR-009 instead.
post #51 of 151
Quote:
Originally Posted by Chefguru View Post

If the sr-009 turns out to really non-require the same level of power, I can see the ges turning into a great bargin. Very exciting!


I am viewing the new interview from Fujiya Avic and, although I have a hard time catching all the words, Stax is clearly saying the efficiency of the new electrode is superior to old design because they're using an even thinner moving diaphragm. Also, if I got it right, they could make the stator thinner by using reinforcement ribs (the idea is to have the stator as thin as possible to increase its acoustic transparency while at the same time making sure it's stiff enough to prevent unwanted vibration from the stator.

 

Anyhow, bottom line is that it should be no surprise if the new design is easier to drive...

post #52 of 151

The new drivers are more sensitive (says so right there in the spec sheet though the difference is tiny) but when has that ever had anything to do with how easy a transducer is to drive?  We are still dealing with the same 66K to 66M load of the other Omegas so why is the SR-007 harder to drive than the SR-Omega when it is indeed more sensitive?  Thinner diaphragm means you need a better amp to control it but I guess these new drivers could be able to defy Ohm's law...

 

As for "In regards to amplification, sometimes less is more you know", how the hell does that apply to the 727? 

post #53 of 151
Quote:
Originally Posted by spritzer View Post

The new drivers are more sensitive (says so right there in the spec sheet though the difference is tiny) but when has that ever had anything to do with how easy a transducer is to drive?  We are still dealing with the same 66K to 66M load of the other Omegas so why is the SR-007 harder to drive than the SR-Omega when it is indeed more sensitive?  Thinner diaphragm means you need a better amp to control it but I guess these new drivers could be able to defy Ohm's law...

 

As for "In regards to amplification, sometimes less is more you know", how the hell does that apply to the 727? 

 

Indeed on the electrical side of things, I have no idea the different the load is to the amplifier. However, on the mechanical side, stax specifically refers to increase in "ease of displacement" of the membrane by using a thinner diaphragm (with less inertia). With the o2, isn't the issue of uncontrolled bass at least partly due to the lack of control of this membrane inertia unless the amplifier has sufficient drive capability? At least, this is how it works with traditional electro-dynamic speakers. The membrane mass in electrostatic transducer is much lower and the stiffness very high by it's still got some elasticity and inertia.

 

Then, in regards to the less is more, indeed I have no idea how different the 727 is from say a KGSS (not so different then?). But the point was also about the power: in an electro-dynamic amp, the first watt matters much more than the 300 Watts of reserve given this is 90% of the typical recording (unless you're listening to overly compressed crap recordings eh ;) ).

post #54 of 151
Quote:
Originally Posted by arnaud View Post




I am viewing the new interview from Fujiya Avic and, although I have a hard time catching all the words, Stax is clearly saying the efficiency of the new electrode is superior to old design because they're using an even thinner moving diaphragm. Also, if I got it right, they could make the stator thinner by using reinforcement ribs (the idea is to have the stator as thin as possible to increase its acoustic transparency while at the same time making sure it's stiff enough to prevent unwanted vibration from the stator.

 

Anyhow, bottom line is that it should be no surprise if the new design is easier to drive...


BTW, the ribs on the stators is driving the manufacturing the costs up as it's a multi-layer fused together under high heat and pressure. Also at the beginning of the video they show the arc assembly and if I heard it right it's milled from aluminum bloc, hence not cheap either compared to previous designs.

 

post #55 of 151

Overall I'm very pleased with the design of the headphone.  To me, the only questionable aspect of the assembly is where the metal frame connects with the plastic headbad.  I just hope that it is a strong connection and won't break.  I hear the SR-507 headband is very beefy, so hopefully it will stand the test of time.  I also with the headband arcs were covered in leather ;)

post #56 of 151

 

Quote:
Originally Posted by n3rdling View Post

O2mk1 definitely changes more with better amplification than the Omega.  I love both.


 

Quote:
Originally Posted by spritzer View Post

The new drivers are more sensitive (says so right there in the spec sheet though the difference is tiny) but when has that ever had anything to do with how easy a transducer is to drive?  We are still dealing with the same 66K to 66M load of the other Omegas so why is the SR-007 harder to drive than the SR-Omega when it is indeed more sensitive?  Thinner diaphragm means you need a better amp to control it but I guess these new drivers could be able to defy Ohm's law...

 

As for "In regards to amplification, sometimes less is more you know", how the hell does that apply to the 727? 


 

Quote:
Originally Posted by arnaud View Post

Indeed on the electrical side of things, I have no idea the different the load is to the amplifier. However, on the mechanical side, stax specifically refers to increase in "ease of displacement" of the membrane by using a thinner diaphragm (with less inertia). With the o2, isn't the issue of uncontrolled bass at least partly due to the lack of control of this membrane inertia unless the amplifier has sufficient drive capability? At least, this is how it works with traditional electro-dynamic speakers. The membrane mass in electrostatic transducer is much lower and the stiffness very high by it's still got some elasticity and inertia.

 

(...)

 

Very interesting discussion.

 

According to Chu Moy, there is a correlation between the mechanical model and the electrical model of an electrostatic transducer.

 

Quote:

The Transducer Frequency Response

 

Mechanical and electrical equivalents of an electrostatic transducer. 
Figure 2

 

Figure 2a shows the mechanical-equivalent circuit of the transducer. m is the mass-per-unit area of the diaphragm, S is the suspension of the diaphragm in the transverse direction, and 2Rm is the damping in the mid frequencies from the impedance of the air. Fo is the peak force-per-unit area on the diaphragm.

 

The electrical-equivalent circuit in figure 2b converts m to an inductance of M = jwm henries, the suspension S to a capacitance of S-1farads, the damping to 2Rm ohms, and the force to a voltage Fosin(wt)V. The high frequency response of this circuit is constrained by the inductance M, which is directly proportional to the diaphragm's mass-per-unit area. Therefore, the lighter the diaphragm, the smaller the inductance and the wider the frequency response.

 

Diaphragm Resistivity

 

 

The motion of the diaphragm is affected as follows: by the diaphragm tension at low frequencies, by the acoustic resistance of air at mid frequencies, and by the mass-per-unit area of the diaphragm at high frequencies. The resonance frequency of the transducer determines the lower frequency limit. If the resonance frequency is too low, it could limit the apparent sensitivity of the transducer.

 

To ensure that the diaphragm maintains a constant charge at low frequencies, no significant current should flow in less than half the time period of the lowest frequency to be reproduced. Given a diaphragm with perfect conductivity and a transducer having capacitance C farads, and low frequency response to 27Hz, then the diaphragm must be fed via a resistance R ohms, such that:

 

RC > 1/(2 x 27) (approx.) 
If C = 150pF (C= eA/d) 
then R > 1 x 108 ohms.

 

However, R cannot be so high as to prevent the diaphragm from charging.

 

 

 

I would like to understand the transducer amplifier interaction in its three main parameters:

 

1) Low frequencies, diaphragm tension, suspension of the diaphragm (S) and capacitance (S-1);

 

2) Mid frequencies, acoustical resistance of the air, damping in the mid-frequencies (2Rm);

 

3) High frequencies, mass-per-unit area of the diaphragm, inductance (M in heries).

 

Transducers specifications:

 

SR-009

SR-007

Frequency response: 5 - 42,000Hz

Frequency response : 6 to 41,000 Hz

Electrostatic capacitance: 110pF (including cable)

Capacitance : 94pF (including cable)

Impedance: 145kΩ (including cable, at 10kHz)

Impedance : 170 KΩ (at f = 10 KHz)

Sound pressure sensitivity: 101dB / input 100Vr.m.s. / 1kHz

Sensitivity : 100 dB / 100 V r.m.s. at f = 1 KHz

Maximum sound pressure level: 118dB / 400Hz

 

 

Since the high frequency response is so-so similar, I do not think there will be a relevant change in the inductance.

 

Is it true that to achieve the same mid-frenquency sound pressure SR-007 will need more power due to the fact of a higher impedance? 

 

So why sensitivity in the 1 khz frequency is so close?

 

I would imagine a frenquency vs. sound pressure chart (always with 100VRMS) and the 1khz region could be the peak. For instance, 500hz and 2 khz will be sightly decreasing, like a parabola.  Is that true? If yes, there would be a relevant difference in sensitivity in the whole mid-frequencies range.

 

How much energy does the amplifier need to deliver to the transducer in other to allow the same sound-pressure with low-frenquencies and high-frenquecies? Do you think SR-007 would need more energy to sound flat (let's say that our limit to say it sounds flat is +/- 3dB 20Hz-20Khz)?

 

I am eager to see the enlightment of these doubts!

 

biggrin.gif

 

p.s.: I am not saying that flat frequency response is the sole parameter to analyze a transducer our the whole sound reproduction chain.


Edited by jgazal - 4/6/11 at 4:26am
post #57 of 151
Quote:
Originally Posted by hentai View Post

Gentlemen.... i've pulled the trigger. Once i've obtained them , i will do a comparsion and post my impression. It won't be a lenghty one as its beyond my ability to write essay long reviews on audio stuff


Congrats on ya pricey purchase! Was wondering where abouts are you located? Hearing your predicament about space and nagging parents have me thinking you might be on this sunny island i call home too.

post #58 of 151

I currently run O2 Mk. 1 using a BHSE amp.  I like the sound, but of course, if something comes along that sounds better that is great.  I would welcome any form of progress.  My problem is that I don't really know of anywhere that I could audition the new model. 

 

Also, I am NOT one of those in the camp of O2 owners that think it is too dark or warm sounding.  I would NOT want greater "clarity" if that means a leaner midbass.  I would only consider a model an improvement if it were actually a bit warmer sounding.  If I read comments saying that it is warmer, then I would find it worth my time hunting down a dealer that would allow me to hook up my BHSE amp for a trial.

post #59 of 151

Nice, thank you for the link! I am reading through it, it is quite fascinating! It's funny, I never really looked into details of electrostatic transducers. How ironic for an engineer who spends his days trying to put some logic into everything ;).

 

As for your questions, I am incapable of answering and will leave this to Birgir... ;)

 

Quote:
Originally Posted by jgazal View Post

 


 


 

 

Very interesting discussion.

 

According to Chu Moy, there is a correlation between the mechanical model and the electrical model of an electrostatic transducer.

 

 

 

I would like to understand the transducer amplifier interaction in its three main parameters:

 

1) Low frequencies, diaphragm tension, suspension of the diaphragm (S) and capacitance (S-1);

 

2) Mid frequencies, acoustical resistance of the air, damping in the mid-frequencies (2Rm);

 

3) High frequencies, mass-per-unit area of the diaphragm, inductance (M in heries).

 

Transducers specifications:

 

SR-009

 

 

SR-007

Frequency response: 5 - 42,000Hz

 

 

Frequency response : 6 to 41,000 Hz

 

 

Electrostatic capacitance: 110pF (including cable)

 

 

Capacitance : 94pF (including cable)

 

 

Impedance: 145kΩ (including cable, at 10kHz)

 

 

Impedance : 170 KΩ (at f = 10 KHz)

 

 

Sound pressure sensitivity: 101dB / input 100Vr.m.s. / 1kHz

 

 

Sensitivity : 100 dB / 100 V r.m.s. at f = 1 KHz

 

 

Maximum sound pressure level: 118dB / 400Hz

 

 

 

 

 

 

Since the high frequency response is so-so similar, I do not think there will be a relevant change in the inductance.

 

Is it true that to achieve the same mid-frenquency sound pressure SR-007 will need more power due to the fact of a higher impedance? 

 

So why sensitivity in the 1 khz frequency is so close?

 

I would imagine a frenquency vs. sound pressure chart (always with 100VRMS) and the 1khz region could be the peak. For instance, 500hz and 2 khz will be sightly decreasing, like a parabola.  Is that true? If yes, there would be a relevant difference in sensitivity in the whole mid-frequencies range.

 

How much energy does the amplifier need to deliver to the transducer in other to allow the same sound-pressure with low-frenquencies and high-frenquecies? Do you think SR-007 would need more energy to sound flat (let's say that our limit to say it sounds flat is +/- 3dB 20Hz-20Khz)?

 

I am eager to see the enlightment of these doubts!

 

biggrin.gif

 

p.s.: I am not saying that flat frequency response is the sole parameter to analyze a transducer our the whole sound reproduction chain.



 

post #60 of 151
Thread Starter 
Quote:
Originally Posted by crumpler View Post




Congrats on ya pricey purchase! Was wondering where abouts are you located? Hearing your predicament about space and nagging parents have me thinking you might be on this sunny island i call home too.



Yes, the little red dot on the world map .....  I am mainly a frugal person,,,, except when it comes to headphones and Japan vacations (but too bad this year is a no-no) , i can spend alot.

 

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