[Danne]

Can't find info about where the XO frequencies are the 1.7. Anyone knows?
Thanks
/Danne

[josh358]

I haven't seen them, but if you go to the Magnestand website's 1.7 page, you'll find a schematic (along with some egregiously incorrect information that you can safely ignore). If you plug the component values in you should be able to find the crossover frequencies -- the woofer/tweeter is a single pole series crossover and the tweeter/supertweeter is .5-way.

[Davey]

I would want confirmation on the accuracy of that 1.7 schematic on the Magnestand page. 

At this point, I don't see any reason for Magnepan not publishing the schematics of the X.7 speakers. 

Cheers,

Dave.

[josh358]

I asked Mark Winey about that, and he told me that there policy is to make the schematics of discontinued models freely available. Then he smiled and said he knew that people would eventually open them up to see what's inside, but that he preferred to keep the schematics of the current models proprietary.

I'm surprised that more people haven't, but I guess no one except PG is eager to modify brand new speakers.

[mav52]

About the only measurements I've ever seen on the 1.7's where here
http://www.hometheaterhifi.com/floor-standing-speakers/floor-standing-speakers-reviews/magnepan-magneplanar-mg-17-flat-panel-quasi-ribbon-full-range-speakers/page-4-the-magneplanar-mg-1-7-speakers-on-the-bench.html

[Davey]

Josh,

The 1.6, 3.6, MMG, etc, schematics were all made available before those models were discontinued.

At this point, I don't know what the big secret really is.  Everyone knows they've switched to a series (or quasi-series) arrangement for the newer models.  We just don't know the details.

Cheers,

Dave.

[josh358]

Now that Jim Winey has handed over active management of the company to Mark it's his call, and while I didn't ask him specifically I gather that he's concerned that Magnepan might lose some competitive advantage if they disclosed the schematics. I do think there's some plausibility in this since the ones we do know about, such as the .5-way supertweeter in the 1.7 and the acoustical .5-way midbass in the 3.7, seem pretty clever to me and not without potential applicablity to the competition (much of which is based on Magnepan's lapsed patents). Through much of the time that Jim was running the company, they were protected by their patents, and this might have had something to do with their decision as well (pure speculation on my part, I never asked).

Also, I imagine that there isn't much of an upside for them to revealing the info, which would interest a few modders and curious engineers who should be cutting vinyl flooring now rather than hanging out on the Planar Circle. And of course the modders can always just open up their speakers and look, as PG did -- they don't seem to have effaced component values or potted anything, the way people normally do when they're trying to hide something.

One argument against keeping them confidential is I think would be that by convention, schematics of audio gear have almost always been made available to facilitate troubleshooting, repair, and modifications. In particular, if something goes wrong and a customer wants to scope out the problem himself, a schematic would make the process easier. Another I think is that their reluctance to discuss the basic technical details that are usually disclosed, e.g., crossover points, has led to a certain amount of resentment online -- although there are other reasons for this than competitive secrecy, in particular, Wendell's principled aversion to the phony "specsmanship" game that is so common in audio marketing and that he feels, rightly, I think, misleads audiophiles into craving components on the basis of features and specs when they should be listening and judging on the basis of actual performance.

Mark also pointed out that today's audiophiles seem less interested in customizing crossovers and the like, and said that when they produced a box with adjustable crossover components (IIRC -- I may have the details wrong) only three people bought it. I gather that this influenced his decision (I've heard) to eliminate the external crossover box, which led to the requirement of a single-pole crossover (due to component size) and the loss of rear-panel biamping capability.

I didn't have the impression that Mark was fanatical about it -- he's an easygoing guy who astounded me with his openness on many topics that most companies would keep confidential -- but rather that he thought it was probably best to keep things under wraps while they can and guard their technical edge, since the basic principles are now known and the patents have elapsed. Their R&D effort is significant for a company that size and remembering how paranoid I was when I was filing for patents I can understand why they might be reluctant to "give it away," though I have no idea whether it's really significant or not.

[SteveFord]

The answer I got was the crossover points are close to the 1.6s. 

[josh358]

The answer I got was the crossover points are close to the 1.6s.

Must have been the woofer/tweeter crossover (about 1 kHz, I think), since the 1.6 doesn't have a supertweeter.

[Danne]

Thanks

I can understand (sort of) if Magnepan won't disclose the schematics. But why not give info about where the crossover freq are ?
All other vendors I know of will give information like that, like giving away speaker weight ...

I thought the 1.6 crossed over at 600Hz. And the 1.7 is a 3-way so saying it has crossover point similar to 1.6 gives just half the information needed.

By the way, anyone knows where is this "supertweeter" or what's it called? placed? I think the 1.7 looks like the 1.6, I see the tweeter on the sides, but I see nothing that shows this is a 3-way. Where is it placed? and can it be seen from the outside?

/Danne

[SteveFord]

I'm running up to the factory this Summer so I'll make it a point to do some 1.7 inquiries for you if no one here can answer.
Just out of curiosity, why do you ask?

I also want to know about incorporating 20.7 technology into a 3.7 size for the possible DIYer.
The last bit is for purely selfish reasons. 
I love the 20.7 sound but they're just too large and overpowering for my house. 
If the factory won't do it, what could an enterprising soul do to make a pint sized version?
I know that people would pony up to buy them.
If I would buy them a lot of other people would as well.
The question is, would you pay ten grand for the 20.7 sound in a 3.7 size? 
I don't believe you can get there with subs and DMWs all over the place.

That's for another day - off to get my new motorcycle!

[josh358]

Thanks

I can understand (sort of) if Magnepan won't disclose the schematics. But why not give info about where the crossover freq are ?
All other vendors I know of will give information like that, like giving away speaker weight ...

I thought the 1.6 crossed over at 600Hz. And the 1.7 is a 3-way so saying it has crossover point similar to 1.6 gives just half the information needed.

By the way, anyone knows where is this "supertweeter" or what's it called? placed? I think the 1.7 looks like the 1.6, I see the tweeter on the sides, but I see nothing that shows this is a 3-way. Where is it placed? and can it be seen from the outside?

/Danne

Yeah, I think they should release basic info like crossover points too. I know where Wendell is coming from -- he wants people to buy Maggies on the basis of their sound and dislikes the usual audio marketing phoniness that makes you cover components on the basis of technology and specs, when those don't really tell you anything about the sound. But, as you say, these specifications have always been released. I know where Wendell is coming from -- he hates phony specsmanship -- but by the same token, not all of us are black box-type people who don't want to know what's under the hoods of their cars. I can't understand going through the world that way, as some kind of dull-eyed cud chewer who simply accepts that there's grass under his feet and sun on his tush.

Anyway, the supertweeter of the 1.7 seems to be the outermost loop (two foil traces) of the tweeter. And it seems to be .5-way, that is, the whole tweeter + supertweeter is driven above 1 kHz, and then the highest frequencies are shunted to the supertweeter segment alone. That would improve high frequency dispersion and also reduce mass. This on the basis of a schematic that PG made, Magnepan hasn't released an official one.

[josh358]

I'm running up to the factory this Summer so I'll make it a point to do some 1.7 inquiries for you if no one here can answer.
Just out of curiosity, why do you ask?

I also want to know about incorporating 20.7 technology into a 3.7 size for the possible DIYer.
The last bit is for purely selfish reasons. 
I love the 20.7 sound but they're just too large and overpowering for my house. 
If the factory won't do it, what could an enterprising soul do to make a pint sized version?
I know that people would pony up to buy them.
If I would buy them a lot of other people would as well.
The question is, would you pay ten grand for the 20.7 sound in a 3.7 size? 
I don't believe you can get there with subs and DMWs all over the place.

That's for another day - off to get my new motorcycle!

I've long thought they should make a small room high-end speaker as well. Of course I don't really know how it would sell, just that there's some demand for it, judging by what people say on these groups.

But -- how can you *get* the 20.7 sound in a 3.7 size? It's easy to do in the mids and highs, but the nature of open-baffle speakers is that the bass they make is proportional to baffle size. So -- how do you do that at a reasonable price?

Another problem presumably is that they're limited in the number of models they can have in their range and different people have different needs. My own pet idea that I mentioned here years ago in the suggestions thread is a modular Tympani -- sell a top end midrange/tweeter panel that goes down to 100 Hz, and can be used either with a conventional sub in a small room or with bass panels that are sold separately. And you could add panels to size the speaker to the acoustics of the room. And it turns out they actually did sell a Tympani mid/tweeter separately in the early days. However, it would presumably be more expensive than a single speaker since each panel adds to manufacturing costs.

[Danne]

Anyway, the supertweeter of the 1.7 seems to be the outermost loop (two foil traces) of the tweeter. And it seems to be .5-way, that is, the whole tweeter + supertweeter is driven above 1 kHz, and then the highest frequencies are shunted to the supertweeter segment alone. That would improve high frequency dispersion and also reduce mass. This on the basis of a schematic that PG made, Magnepan hasn't released an official one.

Thanks for that info, interesting.

Just out of curiosity, why do you ask?

To make a long story short (and probably not understandable) it's about having tweeters in or out on the front 1.7's. I (or my acoustical designer) was just asking since depending on tweeters in/out, we get more/less of HF/LF reflected into the diffuser wall (front wall) and also lower frequencies will not be reflected into the diffusors but instead be absorbed in a membrane absorber.
So XO point was just to understand a little of what frequencies we are moving from in/out.

Thanks for the replies.
/Danne

[josh358]

So XO point was just to understand a little of what frequencies we are moving from in/out.

The general rule about tweeters in/out seems to be that you have to try it both ways, since your room and setup influence which works best. However, in general, the tweeter seems to have more influence than the woofer on image width. So if you're after say a standard equilateral triangle setup, whichever you use, the tweeter should be at an apex. (I use that as a guideline -- many people prefer Maggies somewhat closer together.)

Diffusion is another issue, since most diffusers are effective in the midrange, some in the highs, few in the bass. Since the woofer handles part of the midrange in the 1.7, it seems to me that ideally, you'd want the diffuser to be positioned so it covers the first reflection point of both the tweeter and the woofer, perhaps with some bias to the woofer side since the waves are more likely to diffract around it (i.e., you need a wider diffuser for lower frequencies).

[Danne]

The general rule about tweeters in/out seems to be that you have to try it both ways, since your room and setup influence which works best. However, in general, the tweeter seems to have more influence than the woofer on image width. So if you're after say a standard equilateral triangle setup, whichever you use, the tweeter should be at an apex. (I use that as a guideline -- many people prefer Maggies somewhat closer together.)

Diffusion is another issue, since most diffusers are effective in the midrange, some in the highs, few in the bass. Since the woofer handles part of the midrange in the 1.7, it seems to me that ideally, you'd want the diffuser to be positioned so it covers the first reflection point of both the tweeter and the woofer, perhaps with some bias to the woofer side since the waves are more likely to diffract around it (i.e., you need a wider diffuser for lower frequencies).

Don't want to turn this into a diffuser thread, but..
I know how diffusers work, mine start to work at about 400Hz (most diffusers don't go lower), so in my case it will diffuse the tweeter. The diffusor does not have to cover the first reflection point, in my case it's the second point (getting longer ISD times by doing this), it's still diffused before it gets back to the listening position, which I think was your point. But, getting it diffused has not been the main target, getting a long travel time before it comes back to me was the important thing. Aiming at 15ms ISD.

/Danne

[josh358]

Don't want to turn this into a diffuser thread, but..
I know how diffusers work, mine start to work at about 400Hz (most diffusers don't go lower), so in my case it will diffuse the tweeter. The diffusor does not have to cover the first reflection point, in my case it's the second point (getting longer ISD times by doing this), it's still diffused before it gets back to the listening position, which I think was your point. But, getting it diffused has not been the main target, getting a long travel time before it comes back to me was the important thing. Aiming at 15ms ISD.

/Danne

Actually, I was after the same thing you are -- a long ISD. 10 ms would be minimum, agree that 15 ms would be better. I'm a bit surprised that the second reflection point is making more of a difference here, since, usually, the first reflection to hit your ears is from the first reflection point behind the speakers. Perhaps your room treatment is absorbing it? Just curious.

[Danne]

Actually, I was after the same thing you are -- a long ISD. 10 ms would be minimum, agree that 15 ms would be better. I'm a bit surprised that the second reflection point is making more of a difference here, since, usually, the first reflection to hit your ears is from the first reflection point behind the speakers. Perhaps your room treatment is absorbing it? Just curious.

Yes 15ms is good in a room of my size. Behind the speakers, in the front corners there is like bass traps with a very sharp angle out at the side walls, seen from above there's like a triangle with a very sharp corner at the side wall, so wave first hit this surface (LF gets absorbed since it's a membrane absorber) and then reflects into the front wall, which is covered with diffusors. That means the second reflection point is at the diffusor.
But, as I said, not sure (at this point) how much of the sound that goes into the diffusor, some gets reflected just across the room, sidewall to sidewall, which is what we want, it gives us a much higher ISD. To get a ISD of 15ms in my room that is just over 26"x12" and 7.5" in height is very good and has (as you see) made us use some clever solutions.
But the MG is perfect since there is virtually no floor and ceiling reflections to treat. Though a few Polar pattern measurements we did (too bad Magnepan don't do them and save them, at least they say they don't...) showed more horizontal dispersion than expected, given what everybody says and writes about MG.

/Danne

[josh358]

Yes 15ms is good in a room of my size. Behind the speakers, in the front corners there is like bass traps with a very sharp angle out at the side walls, seen from above there's like a triangle with a very sharp corner at the side wall, so wave first hit this surface (LF gets absorbed since it's a membrane absorber) and then reflects into the front wall, which is covered with diffusors. That means the second reflection point is at the diffusor.
But, as I said, not sure (at this point) how much of the sound that goes into the diffusor, some gets reflected just across the room, sidewall to sidewall, which is what we want, it gives us a much higher ISD. To get a ISD of 15ms in my room that is just over 26"x12" and 7.5" in height is very good and has (as you see) made us use some clever solutions.
But the MG is perfect since there is virtually no floor and ceiling reflections to treat. Though a few Polar pattern measurements we did (too bad Magnepan don't do them and save them, at least they say they don't...) showed more horizontal dispersion than expected, given what everybody says and writes about MG.

/Danne

OK, now I see. Sounds like an interesting room -- sort of an RFZ arrangement for planars? I've toyed with that idea over the years.

I'm not surprised that the polar response is good, the narrow supertweeter means that the tweeter should have much better dispersion than the quasi ribbons tweeter on the 1.6. I'd expect the woofer to have some power response problems at the crossover point since we're talking a 1' wavelength at 1 kHz and it's only single pole, but you're going to get horizontal lobing there anyway due to the crossover. The larger Maggies in particular have excellent power response (narrow midrange and ultra-narrow tweeter, plus the consistency of a full-range dipole pattern rather than the omni bass, cardioid treble pattern of most boxes), and I think this contributes to the naturalism of the line.

I've experimented with suppressing the first sidewall reflections (in a conventional room) by using a mirror so that they're right in the dipole null, and you can hear the added clarity -- subtle, but easily audible. But when I've tried nulling the first reflection point on the front wall with the dipole null it never sounded good.

[SteveFord]

Josh,
The highs should be the same between the 3.7 and 20.7, I just want more midrange and bass but not tons of it.
I'm sure that they're not going to come out with a super 3.7 but if they would I'd be in the market.
Time to hit the sack, I just spent 12 hours in an airplane and on a motorcycle so I'm a little beat.