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Post by audiobill on Jul 28, 2019 7:13:04 GMT -5
My room is 40' x 20' x 18', 14,400 cubic feet. I have found that the best distance from the front wall is when I can walk between my 3.6/Rs, and hear no difference in clarity, frequency response or volume as I do. I think that's the point where the direct and reflected sound are equal. In my room, that's about 4-5', and my listening position is about 10-12' further back. Have you considerred Maggie MODIFICATIONS? Easy to do would be Mye stands. More expensive and controversial would be the Peter Gunn take on Magnestand, which comes with a new crossover and very good woodwork. www.indiespinzone.com/magnestand.htmlThough I don't think he does 3-series any more.... www.myesound.comThe Myestands are what I call 'bridgework and not the way I'd go, but the reviews are generally positive and the mod is doable in your house in just a few hours. Countless DIY options, including various damping and crossover modifications....... Above all? Have FUN. I've been toying with the idea of trying mini-dsp active crossovers, with each speaker segment driven by a 140 watt channel of my C-J Premier 140s. Others have used active crossovers to good effect, and the parameters are available online to match Magnepan's slope and crossover points......I'm just a bit hesitant to stick anything digital in my amplification path from my VTA SP14 or C-J et5 preamps to the Premier 140s. |
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Post by leonski on Jul 28, 2019 12:06:45 GMT -5
Crossover project is viable and on the table. Good. It's too much to go into here, but the Physics of panels and what most consider the awful stuff they ar made of (MDF) works against ultimate SQ. Reframing with wood, a natural composite is of benefit. Another project consists of pole piece damping using Dynamat or similar. Look THAT one up. And I have my own take using Bamboo Plywood for frames. PlyBoo is very heavy, stiff and made of what is technically a grass. As for MiniDSP? Maybe a 2x4HD per speaker. You can use balanced connections to avoid noise pickup in the longer interconnects you'll end up with. And I believe the HD model supports FIR crossovers which have NO Phase Shift thru the passband. dspguru.com/dsp/faqs/fir/basics/ |
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Post by pedrocols on Jul 28, 2019 20:52:21 GMT -5
Crossover project is viable and on the table. Good. It's too much to go into here, but the Physics of panels and what most consider the awful stuff they ar made of (MDF) works against ultimate SQ. Reframing with wood, a natural composite is of benefit. Another project consists of pole piece damping using Dynamat or similar. Look THAT one up. And I have my own take using Bamboo Plywood for frames. PlyBoo is very heavy, stiff and made of what is technically a grass. As for MiniDSP? Maybe a 2x4HD per speaker. You can use balanced connections to avoid noise pickup in the longer interconnects you'll end up with. And I believe the HD model supports FIR crossovers which have NO Phase Shift thru the passband. dspguru.com/dsp/faqs/fir/basics/I wonder what is the beef with the Maggies MDF frames. Aren't subwoofer boxes made out of MDF? |
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Post by leonski on Jul 28, 2019 21:07:36 GMT -5
 Different problem.....but related. Maggie panels dissipate energy into the frame which bounces it back and colors the sound. MY design using wood, and freely based on the ideas of Peter Gunn is to use a natural composite to dampen those vibes.... You will note that heavy speaker BOXES are supposed to be as INERT as possible. The 'Rap Test' tells the story. If its like rapping on a poured concrete wall, you're probably OK. Look at Stereophile tests of box speakers and you'll see that any resonance in the enclosure FEEDS BACK into the sound. And sometimes, even in more $$$ speakers can color the sound. Here is my design for a panel frame made from PlyBoo.....You can clearly see the rounded, difraction limiting front. The rear support is just sketched in but will triangulate and work in such a fashion as to minimize 'twisting' and torsion stress on panel. What you CAN'T see is the panel suspension and other design features which I will sit on until I can test.....And a few other features, including variable tilt..... |
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Post by donh50 on Jul 29, 2019 13:45:45 GMT -5
The panels themselves have resonances (the little "dots" on the panels are to help break them up) that will usually by far swamp resonances in the frames IME/IMO. Decades ago I measured a couple of pair of MG-II or III (forget), one stock, and one with a heavily modified frame. The measured impulse response was a hair better with the massive frame but in listening tests (DBTs) nobody could tell which pair had the extra frame work.
I had occasional issues (service calls) with construction flaws that caused buzzing in the frames or diaphragm mounting points.
Other popular mods "in the day" were to bypass the fuses (usually resulting in a non-warranty repair charge for a blown tweeter), replacing capacitors in the crossover networks (rarely measurable, not sure ever passed a DBT), replacing inductors (again measurable but sometimes audible due to lower driving impedance, mainly in the bass, but a very subtle change if any), removing the socks (minimal benefit IME/IMO and leading to more dust on the panels), replacing the crossover with a different (passive) design (mixed results, and some of the audible changes were not always good ones), using active crossovers to bi- or tri-amp the speakers (usually better performance when done right but an expensive tweak -- I bi-amped my MG-IIIa's for many years), etc.
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Post by leonski on Jul 29, 2019 18:11:03 GMT -5
The panels themselves have resonances (the little "dots" on the panels are to help break them up) that will usually by far swamp resonances in the frames IME/IMO. Decades ago I measured a couple of pair of MG-II or III (forget), one stock, and one with a heavily modified frame. The measured impulse response was a hair better with the massive frame but in listening tests (DBTs) nobody could tell which pair had the extra frame work. I had occasional issues (service calls) with construction flaws that caused buzzing in the frames or diaphragm mounting points. Other popular mods "in the day" were to bypass the fuses (usually resulting in a non-warranty repair charge for a blown tweeter), replacing capacitors in the crossover networks (rarely measurable, not sure ever passed a DBT), replacing inductors (again measurable but sometimes audible due to lower driving impedance, mainly in the bass, but a very subtle change if any), removing the socks (minimal benefit IME/IMO and leading to more dust on the panels), replacing the crossover with a different (passive) design (mixed results, and some of the audible changes were not always good ones), using active crossovers to bi- or tri-amp the speakers (usually better performance when done right but an expensive tweak -- I bi-amped my MG-IIIa's for many years), etc. So much in your post.....some right, some myth and some opinion which other maggie types may or may not agree with. First? Fuse removal and bypass? NEVER do this on a speaker under warranty. And only after your habits are set and you are confirmed as NOT a fuse-killer. Removing by bridging connections is generally considered a good thing. The wiring under the panel is a mess, to be gentle. OH! The Ribbon has a reputation as a fuse protector. This applies to 2 series and 3 series speakers as well as earlier models with ribbon. Frames / Stands? Common misconception is to make 'em like a bridge and massive. IMO, this is a wrong approach since you are after rigidity which can be gotten thru proper materials and design. Peter Gunn puts SCREWS thru the driver to the frame which to me is NUTS. I've designed a clamping system which applies even pressure to the edge AND floats us driver using a 3M product......non-adhesive 8mil Teflon Tape.... Skiing Ninja had crossover replacements for the MG1.6 line but they were $$$. But did use premium parts, like AIR core inductors which have several advantages over the Iron Core used by Magnepan. Designing an air core inductor with the Same DCR as the stock unit is, however a trick. Some crossover modders went to the lowest DCR they could buy, which were non-optimal shaped inductors AND changed the frequency balance of the panel....even if only slightly. Block diagram shows how it would all be connected, IF you wanted a single amp per speaker solution with ultimate biamp flexibility. It even has a sub out which is also completely configurable. Don't forget the MiniDSP has all sorts of input / output options including parametric as well as some of the Mini products able to use FIR filters.......  |
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Post by donh50 on Jul 29, 2019 18:30:11 GMT -5
The mods in my post were all done by folk when I was working for a Magnepan dealer, not something I did or endorse. As a tech it was often my job to clean up the mess, but I also was able to do a number of DBTs to compare various mods (measurements and audibility). It should be apparent from my post that I was not a fan of most mods (then or now).
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Post by pedrocols on Jul 31, 2019 15:52:42 GMT -5
The panels themselves have resonances (the little "dots" on the panels are to help break them up) that will usually by far swamp resonances in the frames IME/IMO. Decades ago I measured a couple of pair of MG-II or III (forget), one stock, and one with a heavily modified frame. The measured impulse response was a hair better with the massive frame but in listening tests (DBTs) nobody could tell which pair had the extra frame work. I had occasional issues (service calls) with construction flaws that caused buzzing in the frames or diaphragm mounting points. Other popular mods "in the day" were to bypass the fuses (usually resulting in a non-warranty repair charge for a blown tweeter), replacing capacitors in the crossover networks (rarely measurable, not sure ever passed a DBT), replacing inductors (again measurable but sometimes audible due to lower driving impedance, mainly in the bass, but a very subtle change if any), removing the socks (minimal benefit IME/IMO and leading to more dust on the panels), replacing the crossover with a different (passive) design (mixed results, and some of the audible changes were not always good ones), using active crossovers to bi- or tri-amp the speakers (usually better performance when done right but an expensive tweak -- I bi-amped my MG-IIIa's for many years), etc. So much in your post.....some right, some myth and some opinion which other maggie types may or may not agree with. First? Fuse removal and bypass? NEVER do this on a speaker under warranty. And only after your habits are set and you are confirmed as NOT a fuse-killer. Removing by bridging connections is generally considered a good thing. The wiring under the panel is a mess, to be gentle. OH! The Ribbon has a reputation as a fuse protector. This applies to 2 series and 3 series speakers as well as earlier models with ribbon. Frames / Stands? Common misconception is to make 'em like a bridge and massive. IMO, this is a wrong approach since you are after rigidity which can be gotten thru proper materials and design. Peter Gunn puts SCREWS thru the driver to the frame which to me is NUTS. I've designed a clamping system which applies even pressure to the edge AND floats us driver using a 3M product......non-adhesive 8mil Teflon Tape.... Skiing Ninja had crossover replacements for the MG1.6 line but they were $$$. But did use premium parts, like AIR core inductors which have several advantages over the Iron Core used by Magnepan. Designing an air core inductor with the Same DCR as the stock unit is, however a trick. Some crossover modders went to the lowest DCR they could buy, which were non-optimal shaped inductors AND changed the frequency balance of the panel....even if only slightly. Block diagram shows how it would all be connected, IF you wanted a single amp per speaker solution with ultimate biamp flexibility. It even has a sub out which is also completely configurable. Don't forget the MiniDSP has all sorts of input / output options including parametric as well as some of the Mini products able to use FIR filters....... View AttachmentI am pretty sure that 99% of Magnepan owners are very happy with the way the speakers sound right off the assembly line or Magnepan would have been out of business a long time ago. |
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Post by leonski on Jul 31, 2019 15:58:25 GMT -5
The mods in my post were all done by folk when I was working for a Magnepan dealer, not something I did or endorse. As a tech it was often my job to clean up the mess, but I also was able to do a number of DBTs to compare various mods (measurements and audibility). It should be apparent from my post that I was not a fan of most mods (then or now). I get it and have no heartburn. But I must add that some measurements taken by the folks on AA are at odds with your results. And Peter Gunn even made the wildly unsubstantiated claim of large increases in sensitivity. I don't think that's likely given the basic physics of the drivers. Some VERY highly qualified persons there with all sorts of related backgrounds. But when you go to first principles and DO see what works, and some with measurments and others by persons with lots of DIY time on the panels, it's clear a few things DO help. Increasing panel rigidity helps. Damping the Pole Piece also helps. I've heard Magnestand verions of both the MMG (really neat but $$$) and the 1.6 which I'm quite familiar with. Both were improved over stock. the MMG owner has incredible hearing and has been thru LOTS of system changes / mods including Apogee speakers and his latest, some MG20 panels which are incredible. His MMG are neat and his claims of slightly improved bass are to be believed. Other characteristics of the panels are also to the 'plus'. I thought they had better prescence than my 'stock' 1.6 panels. I personally think the road to panel improvements are as follows: In no particular order Real wood frame of high rigidity. I'd personally experiment with PlyBoo...bamboo plywood. Proper attachment of driver TO frame. NOT the staples that magnepan uses! Active crossover STARTING with a duplication of the stock crossover transfer function. This will net 1 or 2 db sensitivity depending on model. Tilt adjustment. Some panels already have this feature but I want it calibrated.....a little trig goes a long way! Experimental areas include pole piece damping, adding super tweeters like the NEO8 driver to NON ribbon models and FIR filters in the crossover.... The last is in itself a gigantic project and would require much noodling, experimental time and listening. |
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