Impertinent half serious question...

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josh358

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Re: Impertinent half serious question...
« Reply #40 on: 9 Feb 2017, 08:07 pm »
Here is one person's subjective analysis when playing with wings.

http://www.integracoustics.com/MUG/MUG/tweaks/wings/mike.html

This is based on a 1.6, wonder if it holds true on an MMG?

I definitely agree (I assume that I am OP) that I lack knowledge, but that is what I am here for.
I'm sure it's true of the MMG as well, in fact, I read that very post a few years ago and it's one of the reasons I said what I did. I think his principles are good ones -- keep the wing low, use it on only one side to minimize the organ pipe resonance, and keep it away from the tweeter side.

You'll also sometimes see a single wing running the full length of the speaker, as on the woofer side of the Martin Logan CLX:

https://www.martinlogan.com/clxart/gallery.php

Note the way they've tapered it to reduce resonances.

In terms of frequency response, you have to watch out for the response issues that BDP mentioned. The larger the effective baffle size, the lower the frequency at which the bass response starts to roll off at 6 dB/octave. So when you add a wing, you're lowering that point. The diaphragm of a planar is tuned to compensate for the 6 dB/octave rolloff of the baffle. So when you extend baffle width, you start to get too much bass. So I think you have to experiment a bit.

bdp24

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Re: Impertinent half serious question...
« Reply #41 on: 9 Feb 2017, 08:09 pm »
Here is one person's subjective analysis when playing with wings.

http://www.integracoustics.com/MUG/MUG/tweaks/wings/mike.html

This is based on a 1.6, wonder if it holds true on an MMG?

I definitely agree (I assume that I am OP) that I lack knowledge, but that is what I am here for.

No offense intended! We are all here to pick each others brains, especially Danny's!

aceinc

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Re: Impertinent half serious question...
« Reply #42 on: 9 Feb 2017, 10:40 pm »
Takes more than that to offend me.

My dad used to tell me that I was too ignorant to be offended.

aceinc

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Re: Impertinent half serious question...
« Reply #43 on: 9 Feb 2017, 10:43 pm »
Danny, what is the lead time on shipping the 12" OB sub kits? Two of them.

I was thinking about making some sawdust this weekend. If I order the kits on Monday would I have them by Friday of next week?

Danny Richie

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Re: Impertinent half serious question...
« Reply #44 on: 10 Feb 2017, 12:00 am »
Danny, what is the lead time on shipping the 12" OB sub kits? Two of them.

I was thinking about making some sawdust this weekend. If I order the kits on Monday would I have them by Friday of next week?

I ship the day you order unless you order late in the day.

bdp24

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Re: Impertinent half serious question...
« Reply #45 on: 10 Feb 2017, 12:28 am »
Takes more than that to offend me.

My dad used to tell me that I was too ignorant to be offended.

Ha, good one! Are you going to make W-frames, or H?

aceinc

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Re: Impertinent half serious question...
« Reply #46 on: 10 Feb 2017, 03:43 am »
"W" frames, bought the MDF at HD tonight. Had them rip the MDF into strips one 13", two 13.5" and two 15-1/8" wide.

I have a sliding compound miter saw, that I should be able to do the other cuts with. Since I can't easily dado anything I will probably screw and glue the inner cabinet and finish nail and glue the outer cabinet.

The 15-1/8" pieces are for the outer cabinet to give me a 13/16" overhang on the front & the back for a grill cloth frame. Hopefully that additional distance won't cause any issues with SQ.

On another note;

Someone locally has a large (16'x6') CNC router for $4,700, I am very tempted, but I can't really justify it. If anyone in my area wants to get in the business part time, I have the space and the cash, but not the time to do the work. Well, there would be a learning curve for me as well.

aceinc

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Re: Impertinent half serious question...
« Reply #47 on: 10 Feb 2017, 03:56 am »
On a mostly unrelated topic, what is the consensus opinion of an L-Pad vs a fixed resistor SQ wise?

Since I have a tenuous grasp (at best) on what I am doing when designing a crossover network, I tend to use L-Pads in the circuit to balance things out. This also has to do with my lack of test equipment.

Is this OK?

Is this reasonable for testing and then measure the resistance and replace with a fixed value resistor?

If everything is more or less equal, I would leave the L-Pad in there for playing when I get the speaker into the room.

Danny Richie

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Re: Impertinent half serious question...
« Reply #48 on: 10 Feb 2017, 04:16 am »
On a mostly unrelated topic, what is the consensus opinion of an L-Pad vs a fixed resistor SQ wise?

Since I have a tenuous grasp (at best) on what I am doing when designing a crossover network, I tend to use L-Pads in the circuit to balance things out. This also has to do with my lack of test equipment.

Is this OK?

Is this reasonable for testing and then measure the resistance and replace with a fixed value resistor?

If everything is more or less equal, I would leave the L-Pad in there for playing when I get the speaker into the room.

There are different reasons for both, and nothing wrong with having a properly implemented L-pad in a circuit.

I don't recommend designing the crossover based on electrical parameters or resistance levels. They really have to be designed based on acoustic output.

bdp24

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Re: Impertinent half serious question...
« Reply #49 on: 10 Feb 2017, 06:23 am »
On a mostly unrelated topic, what is the consensus opinion of an L-Pad vs a fixed resistor SQ wise?

Since I have a tenuous grasp (at best) on what I am doing when designing a crossover network, I tend to use L-Pads in the circuit to balance things out. This also has to do with my lack of test equipment.

Is this OK?

Is this reasonable for testing and then measure the resistance and replace with a fixed value resistor?

If everything is more or less equal, I would leave the L-Pad in there for playing when I get the speaker into the room.



Ace, if you want to go with Magnepans, there is a pair of MG 1.6 with Sound Anchor stands on Audiogon right now, asking price $1000. They are located in Texas.

Keithh

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Re: Impertinent half serious question...
« Reply #50 on: 10 Feb 2017, 08:25 am »
Quote
bought the MDF at HD tonight

I know it is too late for aceinc, but don't buy MDF from HD unless you know what you are looking at.
In this forum MDF is always treated as a singular product. It is not! What one person finds on a shelf marked as MDF can
be something completely different than what is in another store. Where I work we presently have 9 brands of MDF available and there are
many more out there. Six are totally unsuitable for speaker building but they all will show up on some store shelf marked as MDF.
Stick to brands from the Pacific NW and Canada(SierraPine or Plum Creek for example). Chain stores will usually have junk
from China, Chile or Argentina. It will cost more but buy from small hardwoods dealers that cater to woodworkers and
actually know what they are selling. If you don't know what the brand is you can usually go by weight. Good brands of MDF are quite heavy compared
to a sheet of plywood. If it is the same weight or lighter than plywood, stay away from it.

aceinc

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Re: Impertinent half serious question...
« Reply #51 on: 10 Feb 2017, 01:43 pm »
I did not compare the MDF weight, but it seemed pretty heavy, if I had to guess as heavy or heavier than plywood.

I suppose the 1.6's would work with the OB's sideways as a base. One concern I have with older Magnepans is delamination and deterioration. I once naively purchased a pair of smallish (don't remember the model) Maggies for $150, and the seller told me one didn't work. He said Magnepan would provide parts to repair it. When I got them home and took the failing one apart, the membrane was dark brown literally flaked apart as I touched it. When I called Magnepan the cost to replace the panel was close to or more than the MMGs. I ended up giving them to a buddy who bought a turntable from me. I have no idea what he did with them.

Since my crossover designs are fairly simple first order affairs, I use the L-Pads to adjust the levels of the various drivers to balance the volume of the tweeter/midrange vs the woofer which is usually lower.

Danny Richie

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Re: Impertinent half serious question...
« Reply #52 on: 10 Feb 2017, 01:51 pm »
Since my crossover designs are fairly simple first order affairs, I use the L-Pads to adjust the levels of the various drivers to balance the volume of the tweeter/midrange vs the woofer which is usually lower.

We have a testing and measuring service. You just cover the shipping cost both ways and we'll run a complete set of measurements, evaluation, and recommendations, for free.

If it is a big heavy speaker though then you might have to show up with it and help set up and take down.

Shakeydeal

Re: Impertinent half serious question...
« Reply #53 on: 10 Feb 2017, 02:07 pm »
We have a testing and measuring service. You just cover the shipping cost both ways and we'll run a complete set of measurements, evaluation, and recommendations, for free.

If it is a big heavy speaker though then you might have to show up with it and help set up and take down.

Now that's what I call "customer service"............

Shakey

aceinc

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Re: Impertinent half serious question...
« Reply #54 on: 10 Feb 2017, 02:12 pm »
Danny, if I were closer, I might be there weekly.

josh358

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Re: Impertinent half serious question...
« Reply #55 on: 10 Feb 2017, 05:10 pm »
I did not compare the MDF weight, but it seemed pretty heavy, if I had to guess as heavy or heavier than plywood.

I suppose the 1.6's would work with the OB's sideways as a base. One concern I have with older Magnepans is delamination and deterioration. I once naively purchased a pair of smallish (don't remember the model) Maggies for $150, and the seller told me one didn't work. He said Magnepan would provide parts to repair it. When I got them home and took the failing one apart, the membrane was dark brown literally flaked apart as I touched it. When I called Magnepan the cost to replace the panel was close to or more than the MMGs. I ended up giving them to a buddy who bought a turntable from me. I have no idea what he did with them.

Since my crossover designs are fairly simple first order affairs, I use the L-Pads to adjust the levels of the various drivers to balance the volume of the tweeter/midrange vs the woofer which is usually lower.
Magnepan changed their adhesive in IIRC 2005 after an R&D effort to find a more stable adhesive. The ones made before then are moisture sensitive or in the very early years sensitive to ultraviolet, but the ones made since then don't delaminate. So what I'd do is get the serial numbers of the Maggies in question, then call Magnepan's service department. They'll tell you when they were made and if they use the newer adhesive.

You can repair delaminated Maggies yourself, by the way -- Magnepan sells you the wire and glue for a nominal price (they can't ship the glue in the winter, though, since it freezes). It's a weekend project -- you remove the fabric socks, take off the old wire, foil, and adhesive with acetone, put new wire and foil on with 3M spray cement, then lightly brush the adhesive over it. But of course if you have to do that, you should pay less for the speakers.

By the way, I heard from Wendell Diller, Magnepan's director of sales -- he's the guy you spoke to. He remembered your call and saw your post on the Asylum. Wendell said he thought that the .7's would work well in your application. The problem with the MMG's from his perspective is that the midrange drivers aren't fast enough. Remember that the MMG is a budget speaker -- Wendell referred to it as a Volkswagen. It offers incredible bang for the buck, but it's entry level and it isn't suited for every application. So rather than couple an entry-level speaker to a pair of OB subs I think you should either go for the .7's, which are maybe $300 above your budget, or buy used 1.6's. The .7's would be great because they use the latest technology and they're really compact -- with the GR woofers you don't need all of the bass diaphragm area of the 1.6.

If it were me, I'd go with the .7's, they've gotten rave reviews.

aceinc

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Re: Impertinent half serious question...
« Reply #56 on: 10 Feb 2017, 06:28 pm »
I am sure this one had UV damage.

I wonder why Magnepan never went the "printed circuit board" approach, where a layer of material was deposited on the membrane. I had a pair of Carver AL III+ that used that technology for the mid/tweeter and it seemed to work pretty well.

bdp24

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Re: Impertinent half serious question...
« Reply #57 on: 10 Feb 2017, 07:39 pm »
I am sure this one had UV damage.

I wonder why Magnepan never went the "printed circuit board" approach, where a layer of material was deposited on the membrane. I had a pair of Carver AL III+ that used that technology for the mid/tweeter and it seemed to work pretty well.

Eminent Technology does as well in their LFT line of magnetic-planar loudspeakers. Bass, midrange, and tweeter drivers, all with etched vapor-deposited conductors, not high-mass wires like Magnepan.

aceinc

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Re: Impertinent half serious question...
« Reply #58 on: 10 Feb 2017, 08:36 pm »
Spoke with Bruce at Eminent Technologies, unfortunately they won't sell their panels separately for DIY use.

josh358

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Re: Impertinent half serious question...
« Reply #59 on: 10 Feb 2017, 11:05 pm »
I wonder why Magnepan never went the "printed circuit board" approach, where a layer of material was deposited on the membrane. I had a pair of Carver AL III+ that used that technology for the mid/tweeter and it seemed to work pretty well.
They did build a facility for that purpose up on the second level of the factory -- I didn't get an interior shot but you can see part of the outside wall on the left in this shot of the factory floor, with a red fire extinguisher on it:



The reason they chosen not to do it that way is that they found that it was too difficult to make production changes. It's a good technology for small drivers like the Eminent Tech or the BG Neo 8 which require a lot of traces and/or can run hot enough heat to melt adhesive, but for larger drivers, it's more practical to use adhesive and wire by hand and most manufacturers of large planars seem to use that approach.

I wonder if the new large ink jet printed circuit technology will change that?