[richard51]

This headphone greatly improve with a bit of the right equalization....

Personnaly like i already said i decrease a bit the db level near 500 hertz to decrease the perceived effect of bass unwanted diffusion on mids and i increase much around 4 KHZ to plug the "hole" there or lack of the lower highs relatively to the upper region ....
I forgot to say it is rewarding to increase progressively the domain between 60 hertz and a little bit more near 30 hertz...

Then at the end the principle is to reinforce the electret cells and the dynamic cells effects by acting on the lower frequency domain of the 2 mainly, with also and importantly a slight decreasing action needed too in the critical 500 hertz where bass encounter mids frequencies.... ( use your hearing to pick the right balance between the db level in your own audio system but the general idea i suggest will stay true i think because another poster here had suggested the same general rule i think in a past post)

The end result is spectacular, i means : a great refinement....

I wait for my three other set of pads now and 2 power cables at low cost and also an extension of better quality for my headphone.....But i already enjoy an audiophile experience rivalling all that i ever have in the past....Not bad for an audio system, all in all, way under 1000 bucks....

I will not kill myself now because fate force me to let go of my speakers and acoustically dedicated room....

 

[Krassi]

Headphone Jack or speaker output?

simply in the headphone jack.

i was actually surprised that those old amps have so freaking much power.
a Atom amp was not able to make them loud enough in comparison... well those technics can destroy planets when i turn on the volume

ill try my tube amp also again if its nicer or not.

well richard51 i really share your enthusiasm regarding the K340 ! i got 3 pairs
I still think about sending them to someone who can mod the crap out of them.

everything sounds amazing on them! If you look at the frequency response graph you would say "i guess they sound crap" but they are the best example that those graphs are pure crap

In 1981 AKG really did a great job to built this milestone!

 

[richard51]

Now for the so call "veil" attributed to the K340....

There is no veil at all at the end, IF, dac, cables ,pads, amplifiers, vibrations and resonance or the synergy of any linked component are adressed to begin with....

At the end of my optimization process now, almost done, no veil subsist....

But someone used to unnatural presentation of most headphones can say that there is a veil in the AKG k340... It is not false, i experimented this "veil" effect for the first time i used the K340 till a month ago....Now, AFTER the completion of my optimization process, i will not call this a veil but a more natural presentation of music with sound "out of the head effect" (holography in 3-d)... People prefering a more 2 dimensional artificial microscopical analysis of sound may go on with the "veil" perception.... I will not contradict them nor approve either....Each has the right to express his experience in his own term because of our different history in audio experience for sure....I am in search for musical reproduction of a string quartet in my room and not confined in my head, i am not in search for sound "precision" for the sake of it.........

I listened some bass impact with my body and feet better than from my past speakers: try Philip Glass "Akhnaten" opera or Bach Organ....

I listened high frequencies of celestial sound just this evening; try Locatelli "arte of violin"....Shivers along spine....High frequency made of steel who melted in silk and duvet....But their geatest attribute for me is a 3-d holographic presentation out of the head....

There is a veil with this headphone if the recording is veiled to begin with or if any audio component linked to them is not in synergy with this marvel of headphone....This is my experience....

Sorry but i think equalization is mandatory with the AKG K340 because of the difficult task posed by the problem of the electret cell and dynamic cell perfect subjectively perceived integration....This headphone is so sensible to external condition and to resonance and vibration of his shell too, that the integration of the electret and dynamic cells CANNOT be objectively installed OPTIMALLY once and for all ears and all external audio condition a priori.... A slight Equalization at the right frequencies weakness points made them celestial.... It is not hard to figure it out, i draw the great line in the post above of this equalization and the rest is a slight personal touch adaptation to each audio environment and ears....

Yes they may be hard work or take some time to optimize but.....I cannot say more, it is the best deal price/S.Q. ratio possible in audio.... They can be purchase for 100 bucks sometimes.... Incredible.... I apologize for my joy.......But this headphone is one of the best kept secret deal in audio world.... I dont know a better one.....

 

[richard51]

Now i am interested by a comparison between the Dharma headphone and the K340....

Someone know that this comparison exist? Here the beginning of one :

https://www.stereophile.com/content...-driver-headphone-enigmacoustics-dharma-d1000

Here also the problem of integration of these 2 cells being presented and attributed also to the Dharma like i did it here for the k340, anyway the reviewer did not compared an optimized K340 with the Dharma and the way an optimized k340 could solve this integration problem in subjective S.Q. term....Anyway the reviewer observed that the Dharma electrostatic driver enter the auditory scene at 12 khz instead of the 5 khz of the k340...And there exist no crossover for the Dharma .... And it seems also there is a bass problem with the Dharma if i read this article correctly which problem did not exist with the design of the k340 at all in my experience, the bass is extensive in the k 340 (the bass raining in the mids problem is easy to solve in the k340 case with a slight equalization decreasing the db level near 500 hertz and vibrations controls of the shell)....It seems at first sight for me, it is easier to optimize the 2 cells problem with the k340 than with the more different non optimizable or less optimizable Dharma in relation to this integration treshold problem between the 2 cells....

Anyway for the price difference the K340, 100 versus 1,400 dollars for the Dharma, the k340 is the better choice for me.... No doubt....

But once the integration of the 2 cells problem is relatively cured, the K340 is very good and better than my 7 other headphones and competing my acoustically embedded speakers/room, if not improving on them....I will choose anyway my k340 instead of my speakers/room now....

 

[richard51]

One of the main reason why AKG K340 is able to recreate an out of the head soundfield are these 5 passive resonators inside the shell and the hybridization of electroacoustic and dynamic technology and their well chosen croosover point at 4 khz where human voices, the guitar and the piano exist at this scale more by their "presence" than their "fundamental" and their "body" ....

There is other tech for example this completely different one from Japan based on elementary acoustic and psycho-acoustic science using like K340 more than one drivers ....
https://www.crosszone-audio.com/products/cz-10/



Then is this "out of the head soundfield" something possible near 100 dollars, instead of more than one thousand dollars in case of the Cz 10? No....

Save for a used pair of AKG K340.....

Modulo some modifications, pads change, vibration controls, equalization, right source,cables and amplification, the price of sonic heaven could be low for us...


For sure the AKG dont rival exactly probably or perhaps perfectly the japan new acoustic tech using many drivers to actualize in one ear the other channel like when we listen to speakers, with ear A listening what is coming from not only speaker A but also from speaker B and from reflecting walls, and the same for ear B relatively to the two speakers A and B and the walls, but in the AKG K340 the internal passive 5 diaphragms resonators and diffusers and the active dual drivers coupled to a crossover at 4KHZ where the guitar for example and the human voice plays with not only their fundamental here not with their body only but now with their presence and air, these passive diaphragms and these 2 cells and their crossover, make possible and make very impactful a slight equalization for the better, making for each of our own different ears and their different specific filtering comb effect a way to play and enter the scene in an improved way compared to homogenuous and one single cell dynamic or planar or electroacoustic headphone , transforming then this hybrid headphone in a more speaker-like experience...

This is my experience with the K340 and the reason why i am not sad and no more frustrated to loose by fate of retirement my mechanically acousticaly equalized room/speakers experience...By the way i created hundred of Helmholtz resonators and diffusers in my room to improve the relation between speakers and room and also i created my own acoustic mechanical crossfeed between my speakers, i am then used to a stereo sound coming all around me and filling the room and not the common sound between speakers and a sound coming from the speakers... Then listening to conventional one cell driver headphone , of any kind, be it dynamical, electroacoustic or planar, is highly frustrating for me....With my room /speakers i was no more using any of my 8 headphones because they sound all of them UNNATURAL.... But fate make me coming back to headphone and the only possible one for me to listen to without frustrations was the AKG K340 AFTER optimization....This is why i am in this thread....

For sure i am eager to buy someday a CZ10 and compare it to the K340 for "out of the head" effect but also for timbre experience and other acoustic characteristics.... I will, but not this year alas!....

 

[richard51]

Anyway if i trust this 6moons review (see under my post) the limitation of the Cz-10, will not be a contender to demolish the AKG K340 it seems.... It seems the tonal balance of the japan headphone will not beat the tonal balance of the K340.... If i read well ....
Vintage or old technology does not means for sure always an underperforming technology ...
By the way the resulting final tonal balance of the K340 is related also the the crossover 4khz thresold, and beside the multiple drivers of the same kind and his complex internal acoustic labyrinth the CZ-10 has no crossover....No electrostatic driver either.... Only dynamics one....Then i guess the tonal BALANCE OF MY k340 is perhaps better for use in all musical genre....

After this review i am not sure i will investigate the cz-10 to improve over the K340...

Any other contender to suggest by anyone here?

My goal is an headphone with high frequencies like razor metamorphosing in silk and bass i listen with my body and voices which are natural and especially a out of the head effect with appropriate recordings....Then an headphone superior to most speakers especially those in a non acoustically treated room....


https://6moons.com/audioreview_articles/crosszone/3/

 

[AmericanSpirit]

One of old K340 users passing by.
I feel K340 has a little hiccup for lower-mid echoing, but it could be EQ’d away. It is one of very unique electrec + dynamic hybrids still. For an electrec full size headphone I personally prefer Sennheiser’s Unipolar 2002

It has crystal razer clear imaging with very neutral tuning.

Also nowadays, I tend to prefer IEM over fullsize cans, because now IEM can also bring you that out of head experience, especially those equipped with Sonion Electret drivers.

Thieaudio’s Monarch is a very very neutral sounding one if you have any interest in trying those.

 

[richard51]

There is 4 points to keep in mind to equalize for your specific ears the AKG K 340 :

I adress each cell, the electret one and the dynamic by increasing substantially the db level of the 30 to 100 HZ frequency range and i increase in the same way the electret over 13 KHZ...Then the 2 cells are reinforced at the same times in the 2 frequency region where they rule ALONE....

Last 2 points: I decrease slightly the 500 hertz point... ( update: it seems a slight decrease around 125 hertz is better then i reset 500 hertz to normal ) This help to solve completely the diffusion effect of bass frequencies into the mids ...Bear in mind that my headphone are heavily damped already then your own optimal point to control this diffusion of the bass in the mids may vary for you, you must listen....

Last but not least, I adress the sensible crossover point the "hole" located at 4KHZ by increasing the db level much there....

All the rest of the range ask for continuous slight specific adjustement proper to our own specific ears needs....I gave my principle and 4 points for equalizing them, the details is dependent upon our own ears/Audio system choices and decision....




Just a word now about the "out of the head effect" of the AKG K340.... this effect is recording dependent ONLY in the k340 case, contrary to the japan headphone i mention above, the CZ-10, which was created to reproduce this "out of the head" effect for all recordings even at the cost of losing the original tonal balance and original recording acoustical atmosphere of each specific music album....The K340 was not designed with this "out of the head " only goal...A more natural sound was their designer prime goal... It is the reason why the K340 and the CZ-10 are completely different beast, save for the fact they use multiple drivers in each case.... The tonal balance of the K340 is probably better if i trust reviews analysing them and if i think about the difference between their technologies...I will not invest now over 1000 bucks to verify the CZ-10 anyway ...

I dont want IEM because the good one cost like a high end headphone anyway....And i dont fell any inconfort with K340 good pads....And anyway which portable amplifier and IEM will beat my Sansui alpha with the k340 in the bass domain? i hear deep bass with my body now, no other headphone i own come near them...

I dont want uni cellular driver too, be it dynamic, planar or electroacoustic, for acoustic and psychoacoustic reason now i dont believe single cells headphone can give all acoustic cues necessary to reproduce timbre and acoustic room cues, and speaker like effect like the "out of the head" effect without losing intimacy, details, realistic timbre and tonality balance ....

It is the reason why after the K340 my search to improve is limited not only by the low cost of what i already own, the k340, but because of his specific astoundingly revolutionary technology even competing with today technology .....

 

[Majoox]

I wanted to add one measurements of the screen mod - indeed, there are some changes in the frequency response. Have now also done this with my other pair.

In fact, as I have already described, the headphones become brighter in the range of the electret from 4 kHz. The few openings of the electret are partially covered by the grille, so I'm not surprised. By the way, I uncovered everything in the grille and in the waterfall measurement there is a weak resonance at 800 Hz since then - overall, the room between ear and driver now have more "space", as with thicker ear pads, because the entire hollow area from the baffle is added. I could not tell whether this had a positive or negative effect on the sound.

Edit: The thin metal of the electret resonates at a high frequency whenever you stop bass-heavy songs. This was "held in" by the plastic grille. I'm going to buy some alubutyl like Dynamat for this to lower the resonance.

Please note that the frequency response is without compensating.

About the green drivers again: The description "bass light" is really wrong. I just played a random auto playlist while analysing the measurements, and modern pop music in particular has such an impact that I was scared (without any EQ).

 

[richard51]

Interesting....

I used self gluing piece of sorbothane duro 70 1/8 inches thick, i glued them inside and some other piece around the external shell instead of dynamat, and a japanese paper Fo.Q Ta 42 designed to eliminate some vibration...

http://www.foq.jp/foqhp_e/product/ta32.html

I also cut off the center of the plastic grid not the perimeter and i think it was better... I only put a thin foam coming with some pad between the driver and my ears.... I cut off the grid first because it was not confort for my big ears....
The end result is higher frequencies so pure and beautiful that nothing i listen to even compared a bit....

To test the high frequencies try the album The arte of violin by Locatelli the version with Wallfisch

https://www.amazon.com/Locatelli-LArte-Violino-Concerti-Op-3/dp/B003XWFLYM/ref=sr_1_14?qid=1669508653&refinements=p_32ietro+Antonio+Locatelli&s=music&sr=1-14

Here the violin plays hours at his highest frequencies and the recording is audiophile grade and the interpretation is perfect....no fatigue at all for 3 hours of violins which a solist playing all along at the highest note possible in a sort of musical game.... it is a marvel of an Italian master of the violin.... Vivaldi was only one, Locatelli is another one master....

Listening to this we know for sure now that the AKG K340 is high end product not only 35 years ago but nowadays too....The reason of this superiority over some electroacoustic is the hybridation impact, and the 5 little Helmholtz resonators around the 2 cells the dynamic one and the electret.... The sound is more realistic and for me more natural.... The AKG are not perfect like i already said.... But which headphone is? My guide and my meter is the ratio S.Q./price.... Here it is over the roof....

And even if timbre perception is the main important factor in sound experience for sure, i want also a reproduction of the recording of an organ in a church like i was in the church listening and with an "out of the head" sound if the recording make it possible, like Marie Claire Alain Bach recorded rightfully integral on organ make it possible........Anything less will kill me after losing my speakers and acoustic room.... K340 give me that.....And i pay them 100 bucks few years ago....

Think about that, and ponder this fact: is the Raal headphone or the atmasphere headphone better on ALL acoustic count anyway? I never listened to these 2 headphones but i know what the k340 can do....To be frank the Akg K340 can be improved but his actual state make me more than happy....I doubt i will throw big money for slight improvement if there is, and i dont think that many headphones at any price can give an "out of the head " effect with most choral music or symphonies or chamber music .....

For high frequencies experience, before the AKG K 340 the continuous listening for only few minutes of high frequencies was painful.... Now i can listen hours without pain the highest audible frequencies possible who melted in the hear like ice becoming warm honey.... I dont joke, try Locatelli 3 cd albums....

I wanted to add one measurements of the screen mod - indeed, there are some changes in the frequency response. Have now also done this with my other pair.

In fact, as I have already described, the headphones become brighter in the range of the electret from 4 kHz. The few openings of the electret are partially covered by the grille, so I'm not surprised. By the way, I uncovered everything in the grille and in the waterfall measurement there is a weak resonance at 800 Hz since then - overall, the room between ear and driver now have more "space", as with thicker ear pads, because the entire hollow area from the baffle is added. I could not tell whether this had a positive or negative effect on the sound.

Edit: The thin metal of the electret resonates at a high frequency whenever you stop bass-heavy songs. This was "held in" by the plastic grille. I'm going to buy some alubutyl like Dynamat for this to lower the resonance.

Please note that the frequency response is without compensating.



About the green drivers again: The description "bass light" is really wrong. I just played a random auto playlist while analysing the measurements, and modern pop music in particular has such an impact that I was scared (without any EQ).

 

[richard51]

After reading this "review" confession, article ( see under the adress) from someone who has listened the raal and atmasphere, i feel happy with my imperfect 100 bucks confortable with big pads AKG K340....
The upgrading reoccuring neurosis is cured for me, more and more, reading this honest review from an honest reviewer.... Thank to him....

He is right on the spot.... There is no perfect headphone on all acoustic counts and confort.... There is no perfect speakers too, save the very costly one embedded in a dedicated costlier acoustic room acoustically tailor made for them.... Thats all....

By the way this line from the article kill the Raal upgrade possibility for me and my K340 : «The SR1a came the closest to frontal localization. Unfortunately, the brain is way smarter than we think. (lol) It sounded like two speakers hung in front of the ear near the face.» The underlining is mine.....The K 340 dont sound like that at all....

I you dont have an acoustically treated speakers/room, try a 100 bucks headphone like me then but choose the right one and stay happy ....

But after choosing the right one you will be in the work of taming them , on shell resonance count, and you will be obliged to equalize them too, and look for synergetical components....

But unlike the author of this article and like me, you will feel happy by sound and spare money....

https://stereoskunk.wordpress.com/2020/10/28/thoughts-on-raal-sr1a-and-mysphere-3-2-vs-raal-sr1a/

Here are an interesting observation from the same article this reviewer confess now that :
« I almost want an earphone that sounds nothing like real. Trying for soundstage or natural tonality is a fools errand. The result, at leas for now, lands you squarely in the uncanny valley. (get it? )
That is, we can adjust for frequency response but without compensating for the timing effects of HRTF, pinna and canal, it’ll just sound natural but inside our heads.»

My imperfect K340 with his 5 Helmholtz resonators and diffusers inside shell and his dynamic and electret cells give confort with big pads, at least for me, tonal realism, and holographic "out of the head" soundstage .... I dont want earphone and i dont need too....No amplifier in a dap will beat my Sansui alpha anyway.... I dont want an organ sound without deep bass and with a sound only in my head at all...

 

[richard51]

Why is the K340 so good?

Simple, the 5 Helmholtz resonators/diffusers fooled the brain to compute the sound in shell cup A coming from the 2 cells with the delay echo coming from the resonators and also the same in shell cup B.... Then we have here like in real life in a room with 2 speakers the wavefront coming from speakers A and B for ears A and B and the brain computing the time delay for recreating the localized sound image.... The brain is fooled by these 5 diaphragms delayed sound and these 2 cells direct sound , acting like speakers A and B for ears A and the same for ears B....In fact for the brain there is 4 speakers: the real speaker A and the virtual speaker B as perceived by ear A and the same for ear B, the real speaker B and the virtual speaker A....I simplified here for sure because reflected timing waves coming from walls also play a role....But it is the same in a cup shell for the reflecting sound coming from the walls of the cup...

Then the magic of the K 340 comes not only from a wise hybridation and crossover well chosen point at 4KHZ where voice, guitar and piano make their "presence" felt and sensible but also from this Helmholtz passive mechanical resonators...I used Helmholtz resonators in the same way near my speakers to improve the holographic filling of the room by the sound when i devised my room .... In my room the sound never came from the 2 speakers but was raining around the room so to speak...I had near 100 Helmholtz resonators among other devices ... The most important one were located near the 2 speakers drivers....

Then you know why i look for an headphone which will make the same thing or something not too different that my room/ speakers did for me...

I dont really look for a K340 replacement or upgrade.... It is unnecessary soundwise, but i am curious, is it possible to crush them with another design headphone? It seems none of the headphones i spoke about here in these last posts will did the job... Changing an headphone for the hype and the pleasure of changing it, especially a magical headphone like the K340 is deceptive endeavour at best and at worst neurosis....


But i am curious, then open to suggestion.... Not completely cured of neurosis perhaps like audiophile are.... After all i am one.... Even if i am satisfied now..... I was satisfied with my room, and now without it i am satisfied by the K340 replacement of my room... I am lucky yes, but it takes a lot of time to figure out my acoustic room and a lot of time to figure out which is the best headphone and how to optimize it.... Luck without work go nowhere....

 

[richard51]

Like i said in a post above i just changed today my equalization to erase this diffusion of bass in the mids frequencies, but i decided to change instead of decreasing the db level around 500 hertz which was my first try to go to 125 hertz instead because the effect near 500 hertz was a relative improvement only but gave me also some unnatural timbre very evident on some instrument like the harpsichord for example ....

WOW !

I just discovered doing so the exact resonance point of my specific headphone, you must know that my headphone are heavily damped against vibration with sorbothane and some other materials, then compensating for this unknown new resonance point after this damping and decreasing very slightly the db level for this 125 hertz frequency was magical.... How did i know? The timbre perception improved for sure, but the timbre will change for ANY modification on any frequency range especially near mid range.... What is causing my Wow! moment was not the change in timbre perception for the better only but also the huge change in deep bass clarity.... This is how this resonance point of the cup shell was destroying the sound and when we discover its location precisely, a slight modification at this point will have a huge impact more than at any other point....

Then be patient, listen many non electrified acoustic instrument, to judge each single timbre modification, and you will do a great job and discover also the resonance point of your specific k340 shell...Mine is not yours because i took off the plastic grid inside and i put damping materials all around inside and outside, then you will do it right also if you listen attentively, I did....

The Akg K340 in truth for me is better than what was said in all positive reviews i ever read before buying them 5 years ago.... And there is many reviews indeed for this "cult" piece of audio engineering .... I cannot believe i pay them 100 bucks....By the way i bought them 5 years ago but i was at this times in my room acoustic experiments and i have not at this time create yet the right environment for the K340, they were only good, not the marvel i have today after the last month, buying for them pads, cables, equalizer, amplifier etc....Fate forced me too work for them....Then dont think that they will be a "marvel" out of the box without any effort from you nor thinking time to optimize them....They are not an easy piece to only plug and play sorry....But they are virtually better than anything i ever listen to speakers included after their rightful installation ....At 100 bucks i call that a miracle....

The hype and paid reviewers induce often a neurosis: upgrading for the "gout du jour" is the "mot d'ordre"....The truth is that what was a good engineeering marvel in the past is always a very good piece today and way better than the 400 bucks Hifiman He 400 i bought 10 years ago for example not even in the same league at all, and anyway, ( they were so badly designed they break up in two for no reason) the K340 trump any of my 8 headphones which i will never listen to again anyway .... Price of an audio piece and hype say nothing about acoustic quality most of the times sorry... We must listen.....We must learn to listen to.....And we must think twice before buying....

 

[richard51]

Majoox,​

I just read your excellent review of the K340 and some of your interesting posts... I feel my actual K340 extraordinary and without no more defects really, my question is : how do you describe the rewiring effects you had done compared to a non rewired one?

I will not dare to do it with my only one pair though, because damping them the right way, with the right pads, without the plastic grid, and with the right amplifier (low noise floor) and source ( very neutral and a more analytic than a "warm" one ), and a slight equalization reinforcing the deep bass frequencies and reinforcing the highs over 13Khz and also reinforcing the 4KHZ crossover point, and last aiming at the specific target equalization for the resonance point of the shell ( in my case slightly decreasing at 125 hertz), after all that, there is no more veil, they give one of the best timbre experience i ever listen to, a bass so deep and clear i feel it with all my body and trembling feet, high "pure silk " frequencies that exceed anything i know even with my 2 Stax, and holographic 3-d imaging "out of the head" filling the room in most well recorded classical albums, an effect existing in none other headphones i ever listen to.... They are not perfect, but among all i know the best thing among all headphones for me....

I dont feel at all after optimization this desynchronization between the dynamic cell and the electret cell and i can listen them for hours without fatigue at all even with the more higher frequencies possible on a violin, i did it.... Then why rewiring them?

To be frank i cannot imagine they could be improved a lot right now to say the least....I could not go back to any headphone i know of after them.... Happily no one know that or could believe it, then they sell used around 100 bucks....

Describing them is impossible using the audiophile terms of neutral, light or dark, because like you said rightfully, they are neither, they are " out of the head" the more natural timbre experience for sure with all good recordings , then roughly half of classical albums for me....

With the Talich quartet, the Beethoven quatuors for example, the musicians are in my room, not in my head behind my forehead....And the high of the violin and the body of the violin are to die for....I listen EYES OPEN, do you know why? Because i look at the musicians who are in some case in front of me and i see them better with eyes open.... I did not joke at all....

​

 

[Majoox]

My posts and reviews are also scattered in time, half a year ago I had a completely different opinion of the K340. But thanks for the praise!

As I have already written: I consider amping more important than any modifications. I currently have the exact comparison with a rewired K340 and a standard one, both now with the (as I find) useful and simple screen mod. I don't hear the differences, neither do I hear a different phase. In the past there were models (exclusively gray) where you could hear that - now (with green drivers) I don't hear any problems at all. The phase problems are probably less obvious, since the green version actually drops off at 4 kHz. I do not consider less than 1 cm difference between two drivers that take over their own "frequency areas" as serious, with conventional speaker designs the way faster tweeter is also not noticable.