MM7's are here

[JackD201]

i wonder with other 2 tower set-ups or separate subwoofer set-ups how much this issue has an effect. especially where the bass towers are behind the main towers. how can it not be significant?

It is significant IMO and they deal with the time domain issues/group delay in many ways. The question is, why go for the complexity of added circuits instead of a purely mechanical approach. There is something they are avoiding.

In pro sound you almost never see "walls" anymore. They are now convex arrays of high directivity speakers with minimal interaction with each other. Sub units are flown too but you will find the bulk of them below stage level.

Then there's the other other debatable issue. When do you "hear" the initial transient of low notes? Is it at the moment of pressurization at the ear or is it when the brain links together the stimuli from the ear and the pressure wave at 1/4 and 1/2 wavelength felt by the body. The latter could have loudspeakers placed farther than 15 ft back of the mains. I think it is a matter of implementation as there is a lot that can be done to bridge the divide if the designer knows what he is doing.

 

[Champ04]

However, I do agree for a speaker this expensive the quality of build is underwhelming. I make this comment because when I replaced a woofer, much to my dismay I found the woofers are screwed straight into the MDF cabinet, using MDF screws! This caused some problems positioning the woofer for assembly. I would have expected threaded inserts and bolts.

I have to admit. I found this very shocking! There are a lot of things I can certainly appreciate about the EA design. But this was totally unexpected.

 

[Mike Lavigne]

It is significant IMO and they deal with the time domain issues/group delay in many ways. The question is, why go for the complexity of added circuits instead of a purely mechanical approach. There is something they are avoiding.

In pro sound you almost never see "walls" anymore. They are now convex arrays of high directivity speakers with minimal interaction with each other. Sub units are flown too but you will find the bulk of them below stage level.

Then there's the other other debatable issue. When do you "hear" the initial transient of low notes? Is it at the moment of pressurization at the ear or is it when the brain links together the stimuli from the ear and the pressure wave at 1/4 and 1/2 wavelength felt by the body. The latter could have loudspeakers placed farther than 15 ft back of the mains. I think it is a matter of implementation as there is a lot that can be done to bridge the divide if the designer knows what he is doing.

i suppose anything is possible, but i'd be skeptical that any separate enclosure bass reinforcment whether from something designed in or added on can be completely optimal when not time aligned. either the wave launch is done in time or it's not. not that it can't be very very good, just not optimal. bass timing in music is pretty critical and we are very sensitive to it.

understand that in my case basically i just moved the main towers back about 1-1.25 inches and aligned the bass towers. the bass towers were not moved other than aligned. that is it. big difference. the main towers had been laser aligned in their previous spot already.....although not laser leveled so that is another minor variable.

prior to this little experience i would have agreed that proper execution of separate bass enclosures on a different plane from the main speakers might acheive the same result but not anymore.

as far as how we hear bass and how that might be a variable, i think our senses do 'align' things automatically. but the more there is a proper 'real' bass event the easier and more confidently our senses interpret it as real. on some cuts it is a subtle improvement, on other cuts it is much more significant. the higher frequency components are percieved by our hearing and our bodies feel the lowest frequency waves in the proper time sequence. until the time smear is exposed by getting it corrected you don't realize what was missing.

if i had bass enclosures not time aligned i would at least experiement to find out how it might factor in. maybe logisitics don't always allow for that but possibly if improvement was heard then choices can be made.

 

[FrantzM]

i suppose anything is possible, but i'd be skeptical that any separate enclosure bass reinforcment whether from something designed in or added on can be completely optimal when not time aligned. either the wave launch is done in time or it's not. not that it can't be very very good, just not optimal. bass timing in music is pretty critical and we are very sensitive to it.

understand that in my case basically i just moved the main towers back about 1-1.25 inches and aligned the bass towers. the bass towers were not moved other than aligned. that is it. big difference. the main towers had been laser aligned in their previous spot already.....although not laser leveled so that is another minor variable.

prior to this little experience i would have agreed that proper execution of separate bass enclosures on a different plane from the main speakers might acheive the same result but not anymore.

as far as how we hear bass and how that might be a variable, i think our senses do 'align' things automatically. but the more there is a proper 'real' bass event the easier and more confidently our senses interpret it as real. on some cuts it is a subtle improvement, on other cuts it is much more significant. the higher frequency components are percieved by our hearing and our bodies feel the lowest frequency waves in the proper time sequence. until the time smear is exposed by getting it corrected you don't realize what was missing.

if i had bass enclosures not time aligned i would at least experiement to find out how it might factor in. maybe logisitics don't always allow for that but possibly if improvement was heard then choices can be made.

Mike

Not sure I completely understand your points .. What do you mean by "aligned"?
The second thing t is that the fact that the speakers are at the same distance with the mains doesn't make them "time aligned" .. This is an entirely different concept.
You may have heard differences when you moved your speakers, I am not debating that fact but it isn't an issue of time alignment. It is rather an issue that by moving the speakers you alter the level and distribution of modes in your; these are a function of both the room dimensions, position of LF sources and room treatments absorption.. You move the speakers a few inches in your case a full range speaker , your mains and you change many things in the bass (thus overall sound balance) ... whether the new position is optimal is an issue that is best dealt with measurements.. however adverse you may be to the notion, and verified by ears.
Last my personal experience with tower speakers suggest that the bass towers do not necessarily provide the best when they are in the same plane as the main speakers, for the most part it did not provide the best results with those I am familiar with mostly the Geneis speakers. My further experience with multiple subwoofers corroborated this as well. As usual YMMV ... but the facts remain that putting the bass tower with the main is not time alignment.

 

[JackD201]

Well, we don't know what's inside the towers Frantz. There's a long list of "it depends" at play. Depending on the design, they may very well be time aligned. I'm assuming the guys at EA did their math and figured the towers blocking the outer radiation of the main towers is a non factor for their intended use (spaced widely).

 

[Mike Lavigne]

Mike

Not sure I completely understand your points .. What do you mean by "aligned"?
The second thing t is that the fact that the speakers are at the same distance with the mains doesn't make them "time aligned" .. This is an entirely different concept.
You may have heard differences when you moved your speakers, I am not debating that fact but it isn't an issue of time alignment. It is rather an issue that by moving the speakers you alter the level and distribution of modes in your; these are a function of both the room dimensions, position of LF sources and room treatments absorption.. You move the speakers a few inches in your case a full range speaker , your mains and you change many things in the bass (thus overall sound balance) ... whether the new position is optimal is an issue that is best dealt with measurements.. however adverse you may be to the notion, and verified by ears.
Last my personal experience with tower speakers suggest that the bass towers do not necessarily provide the best when they are in the same plane as the main speakers, for the most part it did not provide the best results with those I am familiar with mostly the Geneis speakers. My further experience with multiple subwoofers corroborated this as well. As usual YMMV ... but the facts remain that putting the bass tower with the main is not time alignment.

here is the designer, Kevin Malmgren, thoughts on this subject he sent to me in an email. no doubt i'm no speaker designer.

I will try to simplify this as much as possible. The MM7 was designed to have the subwoofer towers side-by-side with the main towers in a complete time and phase aligned orientation, as shown in the picture on our website, and also as how you listened to the mono channel when you were at my place.
While it is true that the lower frequencies have much larger waves, getting them to integrate in phase with the main tower is really not much of an issue when it comes to room placement, meaning you will not experience much if any wave cancellation. However, the wave launch, when having the towers perfectly time aligned to the listening chair is needed to provide a tighter presentation with greater impact, and also to align the harmonic series from top to bottom to produce a seamless and tonally lifelike presentation. This is not to say that you can not move the towers around, because you can.
Remember, we are only talking about a subwoofer tower that is coming in at around 30 to 40Hz at most, so most all music information will be coming from the main towers. The benefit of being able to move the sub towers is if you have a room that is not friendly in the deep bass region (this would have to be a really bad room where even the amplifier controls on the subwoofer modules can not bring the bass up enough). In this case, you may want the main towers where you get the best sonic presentation, but you may have to push the sub towers to another region of the room to get bass all the way down below 40Hz flat. If this was a speaker system contained all in one tower and the best location for sub 40Hz range was all the way against the back wall, imagine how the mid-bass, midrange, depth, etc. would suffer.
The only other reason I could see for moving the sub towers is for aesthetic purposes within the listening space. Some people may not want to have a wall of speakers, and being able to push the sub towers to another location may be more acceptable.

In a nutshell, if you want to stay true to my design, then yes you must have the towers all perfectly time-aligned to the listening chair. However, if your room is not producing good frequency response in this situation and you value that over time domain launch, then you can always move the subs to get the best frequency bandwidth. Or, you may just want to visually downsize the appearance of the speakers in your room.

 

[FrantzM]

Mike

Not much I can make of this as being time aligned ... If you like what you hear ...

 

[audioguy]

The wave length at your crossover (30hz to 40hz) is between about 28 to 37 feets feet. Moving a sub 1.5 inches from the mains is not going to make "much of" a difference in time aligning the subs to the mains.

However, the advantage of separate subs is that they can be placed in the best place in the room for flattest FR and keep the mains where they exhibit the best response/imaging/soundstage/etc. And if I read and understand what the speaker designer said correctly, he is saying just that.

 

[Steve williams]

I thought the same Chuck

 

[Gregadd]

The Wilson WAMM

 

[GaryProtein]

What Kevin, the MM7 designer said in his email to Mike is similar [not exactly the same, but close] to the intentions of the design of the Infinity IRS-V and the Genesis G1.x speaker systems. The bass towers can be positioned over a range of positions to give excellent response and integration of all the drivers.

With regard to being time aligned, one could say in response to the statement that a side by side set of towers could not be time aligned, that neither can a set of standard speakers that have all the drivers in one cabinet [the Wilson being an exception because the drivers are adjustable in their positions], only in those, the drivers are stacked on top of each other, with the woofers generally on the bottom or top and bottom for symmetry, and the midranges in the middle or symmetrically placed more centrally and with and the tweeters on top or grouped in the middle for symmetry cannot be time aligned either, only the discrepancy there is a vertical one rather than horizontal.


edit after Gregadd's post: same thing with the subwoofer placement with the WAMM and/or Alexandria and Thors, and the ML-Statement e2

 

[Gregadd]

ML Statement e2
The Wilson and Martin Logan take the place the woofer where it sounds best vs time alignment.

 

[FrantzM]

Gary

We may have to tkae the discussion elsewhere .. Wilson speakers are not time aligned. Time alignment is much more than physical alignment of drivers .. Crossovers play an important role in time aligning speakers.. DSP may help in aligning drivers but simply moving them won't time-align the drivers...

There are some debate about the need for time alignment and how it is achieved.. THe IRS V are not Time aligned .. this doesn;t stop them from sonding exeedingly good ...

The speakers I have found myself attracted are not time aligned for the most part... so ... not a huge concern for me and having dealt with Genesis and Infinity and multiple subs a la Geddes.. Not much of a concern for me ...

Back to Mike and his MM7 ...

 

[Mike Lavigne]

Gary

We may have to tkae the discussion elsewhere .. Wilson speakers are not time aligned. Time alignment is much more than physical alignment of drivers .. Crossovers play an important role in time aligning speakers.. DSP may help in aligning drivers but simply moving them won't time-align the drivers...

There are some debate about the need for time alignment and how it is achieved.. THe IRS V are not Time aligned .. this doesn;t stop them from sonding exeedingly good ...

The speakers I have found myself attracted are not time aligned for the most part... so ... not a huge concern for me and having dealt with Genesis and Infinity and multiple subs a la Geddes.. Not much of a concern for me ...

Back to Mike and his MM7 ...

i can't argue speaker design on a technical level. i do know that the MM7's do have a first order crossover and are suppose to be time aligned according to Kevin.

but forget about all that technical stuff.

the bottom line is the degree of improvement i heard in my large room with the main towers being moved back 1 inch and the bass towers turned slightly. length of a 30hz wave? who cares. time aligned? don't know.

result.

much much better up and down the whole frequency range. yes.

and after hearing that it caused me to consider how lots of set-ups might also benefit. hopefully someone reading will try it and get a free performance upgrade due to an open mind. or at least learn something.

will all other multiple tower/subwoofer systems get the same benefit?

no idea at all....but my feeling is that many would get some benefit. likely the precision and resolution of my system optimizes any benefit.

 

[rbbert]

It really depends on the crossover, as Frantz has mentioned.

 

[A.wayne]

Gary

We may have to tkae the discussion elsewhere .. Wilson speakers are not time aligned.

Agree ...

Time alignment is much more than physical alignment of drivers .. Crossovers play an important role in time aligning speakers.. DSP may help in aligning drivers but simply moving them won't time-align the drivers...

Dis-agree,

DSP is attempting to do electrically , what one does physically by time aligning, there is no substitute for physical alignment , electrical signal processing does not come close and is just band-aid ...

Agree acoustic phase alignment from the xover design is necessary, but is equally critical to physical placement ...

There are some debate about the need for time alignment and how it is achieved.. THe IRS V are not Time aligned .. this doesn;t stop them from sonding exeedingly good ...

The speakers I have found myself attracted are not time aligned for the most part... so ... not a huge concern for me and having dealt with Genesis and Infinity and multiple subs a la Geddes.. Not much of a concern for me ...

Back to Mike and his MM7 ...

If you favor accuracy and 3dim sound, you will favor time alignment, all the panel speakers i have ever heard suffers from smearing, lost details are not missed by those favoring their big open sound, some like it , others not , I'm greedy , i like both....


TIme aligned speakers have better perspective, big is big , small is small, not so for none aligned speaker, where sizing of instruments are lost , remember now very difficult to get this right , no speaker is technically fully aligned (esl57 is the closet i have ever measured) , but the closer you get, the better the details , seated distance is very critical for alignment ...


Regards,

 

[Gregadd]

Yeah I've posted detailed articles on phase and time alignment before. I posted the pictures of the WAMM and Statement to show examples of placing the upper frequency modules where they sound best and the woofers where they sound best.
With respect to the MM7 I would go with the designers' preference. Especially if you are getting good results.

I think what most are discussing is aligning the drivers along the baffle so that the driver voice coil is in perfect vertical alignment.

 

[Champ04]

When John Dunlavy first came out with his TSW subs they were designed to sit right next to his other speakers with precisely the same distance to the listening position.
Of course, Dunlavy was best known for being first and foremost about time and phase coherency. He was able to show, in his sota anechoic chamber that this was best.

I've found it to be sometimes challenging to get the positioning correct when the slopes are not first order and/or different from each other.
Getting a pair of subs (2nd order) to match well with my mains (1st order) meant tweaking the phase angle on the sub control quite a bit.
My conclusion was that, if both mains and subs are 1st order slopes, then definitely place them side by side and tweak output level if necessary. If there is a mismatch OR either one uses a higher order slope, then the "optimum" position could be almost anywhere. (relatively speaking.)

 

[rbbert]

...I've found it to be sometimes challenging to get the positioning correct when the slopes are not first order and/or different from each other.
Getting a pair of subs (2nd order) to match well with my mains (1st order) meant tweaking the phase angle on the sub control quite a bit.
My conclusion was that, if both mains and subs are 1st order slopes, then definitely place them side by side and tweak output level if necessary. If there is a mismatch OR either one uses a higher order slope, then the "optimum" position could be almost anywhere. (relatively speaking.)

Quite to the point. If the Xovers are other than 1st order, there will be a phase shift (making physical time-alignment essentially meaningless), and I doubt many (any?) subwoofer low-pass filters are 1st order, although digital Xovers can easily compensate for that phase shift.

 

[Champ04]

I doubt many (any?) subwoofer low-pass filters are 1st order,

Vandersteen's and the Dunlavy TSW are the only ones I've ever come across.