Evolution Acoustics MM7 thoughts and impressions

microstrip

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Perhaps it would be a good idea to get the actual specification for the crossover point before we lambast the design...

Lee

Even if we get the actual specification it will tell us very little. You can get fantastic results with non conventional crossover techniques - thing that the highly praised Dynaudio Consequence Ultimate Edition is a 5 way speaker with crossover frequencies of 800 Hz / 1400 Hz / 2700 Hz / 15000 Hz. The bass speaker holds up to 800 Hz (although it is mounted at ear level, the super -tweeter is at the bottom). As some one wrote before, what counts most is the implementation.
 

RBFC

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Even if we get the actual specification it will tell us very little. You can get fantastic results with non conventional crossover techniques - thing that the highly praised Dynaudio Consequence Ultimate Edition is a 5 way speaker with crossover frequencies of 800 Hz / 1400 Hz / 2700 Hz / 15000 Hz. The bass speaker holds up to 800 Hz (although it is mounted at ear level, the super -tweeter is at the bottom). As some one wrote before, what counts most is the implementation.

Folks were on the rampage about the chosen crossover frequency when they didn't even know what it was! Experienced listeners will probably detect anomalies in a speaker's response that lie in the voice region, and it's all about the listening anyway.

I hope Mike gets his set soon, and enjoys the heck out of them!

Lee
 

rockitman

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Lee, good point, but it for this very reason I never post our crossover points. The only thing that matters is how it sounds. People can speculate all they want, but there is no way they can tell you how it sounds by reading specs.

+1 JT


Congrats Mike !!!!
 

microstrip

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Folks were on the rampage about the chosen crossover frequency when they didn't even know what it was! Experienced listeners will probably detect anomalies in a speaker's response that lie in the voice region, and it's all about the listening anyway.
(...)

Lee

Lee,

I am sure these folks will hate (or love, after listening to it ) :) the voices of sopranos played by a speaker with crossover points at 55Hz, 180Hz, 250Hz and 3kHz - the human voice range goes between 60 and 7000 Hz.
 

FrantzM

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Hi

Audiophile orthodoxy has come up with the notion of "slow" woofers and "fast" midrange drivers. The physical reality is that most woofers are comfortable up to 1000 Hz and that includes 18 inchers. yes they beam at those frequencies but they work well there.. So a 8 inch working up to 500 Hz is not a problem at all .. it is actually a very interesting approach... leave the woofer to work up to the Schroeder frequency. Leave the midrange and the upper frequencies to a MTM configuration. The arrangement of the MM7 as I have seen would tend to carry the same flavor throughout most of the frequency band .. I am almost certain the ceramic drivers of the midrange would be at ease up to 6~7 KHz or even higher ... In that design I can infer that 90% of the audible range is carried by the ceramic drivers ... Talk about one flavor
While I do not plan to acquire this speaker (The MM3 is all that I need) I can imagine how good it must sound based on what I have heard about the MM3 ... I know I wil audition it however ;)

I believe however that a manufacturer should be a little more forthcoming with the specs. There is nothing to hide there .. Really ... Let's not play take too many pages from the Bose playbook... I know specs alone will not tell me how a given product sounds but it can give me an idea... i may need some specs to decide if auditioning is worth my while.
 

Mike Lavigne

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Lee,

I am sure these folks will hate (or love, after listening to it ) :) the voices of sopranos played by a speaker with crossover points at 55Hz, 180Hz, 250Hz and 3kHz - the human voice range goes between 60 and 7000 Hz.

i know your 'hate' comment is tongue in cheek; but i can say i heard vocals from the MM7 that were to die for.
 
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mep

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People, please relax. I merely asked a question with regards to the 500 Hz crossover point. The designer of the Evolution Acoustic speakers has been very successful with his designs. I was in JTinn's room at RMAF and was blown away at how good the cheapest pair of Evolution Acoustic speakers sounded. I enjoyed hanging with JTinn and Mike Spitz and getting a chance to hear a 30 ips tape of Louis Armstrong singing St. James Infirmary. The memory of the sound of that tape is not something I will soon forget.

The bottom line is that I was just a little surprised when Mike said the midrange driver crossed over to the woofer at 500 Hz. Who knows what the true crossover point is and what the slopes are? Only a couple of people I'm sure. You can't pass judgement on something you haven't heard and I'm not passing judgement because of course I have never heard them.
 
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MylesBAstor

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andromedaaudio

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I dont want to discuss speakers here to much , but letting a 15/18 inch go up to 1000 hz without large distortion is nearly impossible and will not sound nice ,at least not to me , in the mm3 the 15 inch are crossed at 120 and in the mm7 they are crossed at 35 -50 hz if i recall correctly .
the accuton 7 inch mid will certainly not be at ease (without a lot distortion)at 6-7 khz and it is not designed to do that .
Most designers stay well between the freq extremes of a particular unit to implement it into a loudspeakersystem
Hi

Audiophile orthodoxy has come up with the notion of "slow" woofers and "fast" midrange drivers. The physical reality is that most woofers are comfortable up to 1000 Hz and that includes 18 inchers. yes they beam at those frequencies but they work well there.. So a 8 inch working up to 500 Hz is not a problem at all .. it is actually a very interesting approach... leave the woofer to work up to the Schroeder frequency. Leave the midrange and the upper frequencies to a MTM configuration. The arrangement of the MM7 as I have seen would tend to carry the same flavor throughout most of the frequency band .. I am almost certain the ceramic drivers of the midrange would be at ease up to 6~7 KHz or even higher ... In that design I can infer that 90% of the audible range is carried by the ceramic drivers ... Talk about one flavor
While I do not plan to acquire this speaker (The MM3 is all that I need) I can imagine how good it must sound based on what I have heard about the MM3 ... I know I wil audition it however ;)

I believe however that a manufacturer should be a little more forthcoming with the specs. There is nothing to hide there .. Really ... Let's not play take too many pages from the Bose playbook... I know specs alone will not tell me how a given product sounds but it can give me an idea... i may need some specs to decide if auditioning is worth my while.
 
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Mike Lavigne

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I dont want to discuss speakers here to much , but letting a 15/18 inch go up to 1000 hz without large distortion is nearly impossible and will not sound nice ,at least not to me , in the mm3 the 15 inch are crossed at 120 and in the mm7 they are crossed at 35 -50 hz if i recall correctly .
the accuton 7 inch mid will certainly not be at ease (without a lot distortion)at 6-7 khz and it is not designed to do that .
Most designers stay well between the freq extremes of a particular unit to implement it into a loudspeakersystem

the 15" woofers in the MM3 have an adjustable crossover for room tuning which nominally can be adjsuted to crossover to the 7" mid-range anywhere from 50hz to 150hz. practically speaking the range of use is about 70hz to about 115hz. about 100hz is typical. you can also adjust bass gain, 'Q', and bass extention independantly.....as well as turn on or off a 'rumble filter'.

like anything, it's the execution that counts; and once dialed in, the mid-bass <-> deep bass transition sounds seamless and lively.
 

Mike Lavigne

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above a few posts there was discussion about the MM7's and the crossover. i found an explanation on the Evolution Acoustics website which goes much further than i could to explain how Kevin Malmgren approaches crossover design. i knew it was first order and quite simple but rather than my viewpoint here it is from the designer himself. and to be very clear, Kevin never told me that the woofer and mid-range crossed over around 500hz, that was simply me throwing that out. so my bad.....and i'm sorry i did that as it sort of side tracked the speaker discussion.

i hope this helps;
Question 9:



Evolution Acoustics speakers (with the exception of the subwoofers) employ a “Constant Voltage” crossover. Would you explain how such a crossover is constructed, how it differs from an ordinary passive crossover, and what its benefits are?



Response:



First of all we need to clarify that a Constant Voltage Crossover Network is not that mysterious. It is simply a passive network which exhibits constant voltage transfer, and is the only type of engineered design that will result in true time coincidence and phase coherence, otherwise known as first-order. Typically, most manufacturers will try to obtain this result through a common parallel network design, having one part in series with each driver. However, we employ what is known as a series design which is inherently advantageous.



Crossover components and transducers all have various tolerances in their values. These tolerance differences will always affect the total network voltage response in a typical parallel network, making it almost impossible to guarantee a true constant voltage design from speaker to speaker. In a series network, the drivers are connected in series across the amplifier output, and there are no crossover component tolerances in the direct signal path to contend with. In this type of design the sum of the voice coil voltages will always be equal to the driving voltage, thus a true constant voltage design.



The main benefit to this type of design is that there is no energy or driving voltage loss. This results in a much more dynamic presentation, because there is nothing between the amplifier and the drivers. Basically, transients are fully in tact and not suppressed by capacitors, inductors or resistors. So, when we rate a speaker at 93 dB sensitivity that is an extremely conservative estimate. You basically will experience greater dynamic contrast than with traditional parallel network speakers rated at higher sensitivities.



Another benefit to this type of design is extreme purity of signal. Because there are no capacitors or inductors directly in the signal path, there is nothing to color the integrity of the signal. Not even the most expensive capacitor in the world will sound better than a direct wire from the amplifier to the tweeter, and there is no arguing that. It is true that all of the shunt or parallel components can have some influence on the overall resulting sound of the speaker, so that is why we use all top shelf components in our crossover network, from hand made reference grade film and foil capacitors to heavy gauge pure copper flat ribbon air core inductors.



The final advantage of this type of crossover topology is the way it handles driver behavior above and below the crossover point. Without getting too technical, this type of design maintains a wide overlap of typical first order slopes around the crossover point and then sharply falls off after a few octaves in each direction. The result is true phase coherent performance with added protection on the bottom end of the tweeter and filtering of upper frequency break up in the midrange, which aids in providing better off axis response than typical first order parallel network engineering.



We must also point out that all of our crossover engineering is performed through the use of very sophisticated computer-aided design applications. However, we do not rely entirely on computer generated optimizations for final circuitry, as some manufacturers do. We perform real time measurements as well to verify all computer-based suggestions. We do use our ears to also verify results, but unlike some manufactures that design by ear, we always insist that the design must be as perfect as possible from a measurement standpoint, and will always double check through measurements that any changes made by ear are truly valid. We do this to ensure that we are not imparting our own coloration preferences on the design to ensure as natural a presentation as possible.
 

fas42

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A first comment about this "constant voltage" crossover is that if the amplifier goes bad, and puts a DC voltage across the speaker it will take out every single driver, unless the speaker has very sophisticated protection. And if it has the latter, how much "damage" does that do to the sound?

Frank
 

Mike Lavigne

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A first comment about this "constant voltage" crossover is that if the amplifier goes bad, and puts a DC voltage across the speaker it will take out every single driver, unless the speaker has very sophisticated protection. And if it has the latter, how much "damage" does that do to the sound?

Frank

so far i lived with that 'constant voltage' crossover for close to 6 years with zero incidents; and i've had multiple amps in my system. and i've not heard about any other Evolution Acoustics customers toasting a driver. and the mid-range is ceramic so it would explode with a bad DC spike if it was a problem, as i did experience in the past. so seems like it is a safe design.

not sure we'd like speakers (very much) with enough protection to guard against spikes from amplifiers. you'd need to be listening thru that protection. you need to choose your poison.

the solution is get a high quality amplifier. if you have an OTL tube amp then you are vulnerable....my Tenor OTL's did take out some ceramic mid-range drivers in my Kharma Exquisites back in the day a couple of times. but they sounded lovely!
 
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garylkoh

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A first comment about this "constant voltage" crossover is that if the amplifier goes bad, and puts a DC voltage across the speaker it will take out every single driver, unless the speaker has very sophisticated protection. And if it has the latter, how much "damage" does that do to the sound?

Frank

No, it will not.

The crossover components are in parallel with the drivers. If the amp goes bad, the DC voltage will be shunted across the inductors in parallel with the drivers. Since they use excellent inductors with almost zero ESR, if anything, the amps will blow up before the crossover or drivers.

This type of design also takes into account bad SS clipping as the capacitors in parallel with the drivers will shunt the high-frequency, protecting the tweeters as well. In all, an excellent design that does no wrong.

Series crossovers are wonderful things - it's just that loudspeaker designers of old never had the computational resources to design them properly. Now, with good mathematical modelling and computer aided design, we can use them at ease.

Sorry, jtinn for intruding in your thread, but I had to right a common misconception.
 

fas42

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No, it will not.

The crossover components are in parallel with the drivers. If the amp goes bad, the DC voltage will be shunted across the inductors in parallel with the drivers. Since they use excellent inductors with almost zero ESR, if anything, the amps will blow up before the crossover or drivers
Good point, Gary! I was thinking of the normal situation where a capacitor "protects" the high frequency drivers, but as you say, at least in the case of a first order crossover, the paralleled inductor will take the majority of the current.

But, since I've got your attention, and you have much experience in this area, can one do better than a first order crossover while still having no components in series with the drivers?

But I don't get the SS clipping thing, which brings up another point. Evolution Acoustics tries to claim that the components are not on series with the drivers: well, take the tweeter for example, the actual current which is driving the tweeter passes in series through the capacitor paralleling the low frequency drivers, so all non-ideal behaviour of those capacitors is well and truly bestowed upon the speaker ...

Frank
 

FrantzM

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Good point, Gary! I was thinking of the normal situation where a capacitor "protects" the high frequency drivers, but as you say, at least in the case of a first order crossover, the paralleled inductor will take the majority of the current.

But, since I've got your attention, and you have much experience in this area, can one do better than a first order crossover while still having no components in series with the drivers?

But I don't get the SS clipping thing, which brings up another point. Evolution Acoustics tries to claim that the components are not on series with the drivers: well, take the tweeter for example, the actual current which is driving the tweeter passes in series through the capacitor paralleling the low frequency drivers, so all non-ideal behaviour of those capacitors is well and truly bestowed upon the speaker ...

Frank

Frank

Do you have the schematics of the MM7 crossover? Your statements suppose that you know the particulars of the MM7 implementation do you? Where did you get them?
 

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