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Post by fbczar on Jan 6, 2023 16:54:44 GMT -5
Relative to power requirements what effect do you think using subwoofers has with Maggies? Since Maggies use shallow crossovers between their bass and midrange panels, and in some cases forego a crossover in favor of mechanical tie downs to control what frequencies are handled by which panel, it seems to me giving the big panel less to do may improve the midrange. I am talking about using an electronic crossover like the one in the XMC-2 rather than playing the Maggies full range and trying to blend a sub in. Short answer: I agree. I have used a subwoofer since my first pair of Maggies back in 1979. The panels have limited displacement so large bass signals require large area and even then distort heavily when driven by deep bass signals. A look at equal loudness curves shows we are less able to hear bass frequencies, so deep bass (~100 Hz and under) requires 10x to 1000x the power of say a 1 kHz tone, exacerbating the problem. Adding a sub to offload the panels (applies to ESLs as well) greatly improves their performance over most all frequencies and means you can get away with (much) less power. My first sub was a DIY servo design and I incorporated an active crossover to roll off the bass at 18 dB/octave. It made a huge improvement both subjectively (to my ears) and measured (much lower distortion, greater dynamic range before the panels were overdriven, extended frequency response from the sub which went to 16 Hz before rolling off). Since the bass/midrange panels are not mechanically decoupled (isolated) the improvements definitely went well into the midrange. The design has changed somewhat since then, but the principles and improvement possible by adding a sub still apply IME/IMO. Integration is not all that difficult these days when DSP is readily available. Back then, my sub control included all-pass stages as well as the servo control and crossover circuits so I could time-align the sub(s) and panels. After that initial setup, I upgraded from MG-I to MG-IIIa speakers, but kept the sub and controller. I worked for a store that sold Magnepan and helped other customers integrate subs into their systems as well, including several Tympani and MG-20 owners who weren't sure they needed or wanted a sub until after they heard the difference. It is not just the LF extension, it is the cleaner sound from the panels, and ability to locate the sub to counter room modes, that made (makes) a difference. I still have the old MG-IIIa speakers boxed up, may pull them out again someday. My last stereo system with them used an ARC D-79 for the mid/tweeter, Counterpoint SA220 on the bass panel, and my old sub; they sounded glorious to me. They continued to serve in the HT days when I added a CC3 center and four MC-1's for surround and rear duty, with a set of Rythmik subs, before finally retiring them in favor of a set of conventional speakers. The HT system used several AVRs, lastly an Emotiva XMC-1 with Emotiva Gen1 XPA-2/XPA-5 amplifiers. I am still using the amplifiers though have changed the processor to a JBL SDP-75. FWIWFM - Don Great post! I saw a recent pair of videos posted by a YouTuber called OCD HiFi Guy who made a tour of the Magnepan factory. The videos were full of info from Magnepan employees. If someone who owns Magnepans watches those videos a sub will be in their future. Their description of how the bass and midrange panels combined to create an effectively larger bass panel was eye opening. The new Magnepan Di-Pole Subs should be really interesting. They handle higher frequencies so well I think they will supplant bass panels entirely in existing Magnepan designs. What do you think of removing the fuses for midrange panels and the ribbon tweeter in a 3.7i? Is the danger of blowing a tweeter really that great, especially if you use a sub and lower the demands on the main amp so the possibility of clipping is practically eliminated? |
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Post by donh50 on Jan 6, 2023 17:49:15 GMT -5
Great post! I saw a recent pair of videos posted by a YouTuber called OCD HiFi Guy who made a tour of the Magnepan factory. The videos were full of info from Magnepan employees. If someone who owns Magnepans watches those videos a sub will be in their future. Their description of how the bass and midrange panels combined to create an effectively larger bass panel was eye opening. The new Magnepan Di-Pole Subs should be really interesting. They handle higher frequencies so well I think they will supplant bass panels entirely in existing Magnepan designs. What do you think of removing the fuses for midrange panels and the ribbon tweeter in a 3.7i? Is the danger of blowing a tweeter really that great, especially if you use a sub and lower the demands on the main amp so the possibility of clipping is practically eliminated? Thanks! Magnepan has had dipole "woofer" panels for some time; they supposedly have a new dipole sub array using conventional drivers but I've not seen it (it was shown as part of a smaller 30.7 "apartment" system). I am not really a fan of dipole subs; they sound appealing and seem like the perfect match, but in practice they tend to be boomy and hard to align. The panels act like a point source at sub frequencies anyway, since wavelengths are much longer than the panel size, and I prefer to roll off the bass steeply below the crossover to offload the panels. IME/IMO the "blending" problem is way, way overplayed and the "speed" issue is bunk. Magnepan has done some interesting things over the years and I've lost track. They have done things like asymmetric crossovers with a low slope to "use" the greater panel area, and either they or one of the other panel makers interleaved bass and midrange wires/traces to create a larger effective bass panel area. Blowing the midrange takes some doing, but the ribbon tweeter is much more fragile. When I called 10+ years ago about getting my MG-IIIa's refurbished they told me I must be the only one who still using the original ribbon tweeter...  (Exaggeration I am sure but...) The problem is less clipping (though that will do it) than just playing too loudly and blowing the tweeter without realizing it, or an accidental "pop" from a failing component or user issue (e.g. tripping over an interconnect or power cord, sending a full-volume blast to the speakers, don't ask how I know this). I have been hearing users claim great improvements from strapping the fuses for years. What I know are (a) repeated blind tests have shown no difference and (b) when I was a tech strapped fuses were a great revenue stream for the repair shop. I wouldn't do it. I tried it, convinced myself I heard a difference, and then blind testing proved it was nothing more than perceptual bias. My advice is to leave the fuses in place. When Magnepan says they are "fragile" they aren't kidding. Other popular ways to blow the tweeter include vacuuming the dust off the panels and accidentally letting them "flop" flat on the floor pulling them out of the box. More than one customer "back in the day" rued waiting a day for me to bring them and set them up, instead taking them home and doing it themselves, then slipping (big, awkward panels) and letting one drop flat whilst putting on the feet. One poor fellow had them all set up and slipped pulling off the magnetic protection strip, blowing a tweeter right before his first listen. Then there are pets and kids... I had to repair mine twice when my Blaze Linear 700 self-destructed but the fuse saved the ribbon. Anyway, FWIWFM - Don |
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KeithL
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Post by KeithL on Jan 6, 2023 18:03:18 GMT -5
The real issue with dipole subs is basically that they are in fact dipoles. At relatively high frequencies "sound waves" act quite like waves... so sort of like light. But, at relatively low frequencies, they act more like "moving air" or "air pressure". Basically, the panel moves forward, pushes air away from the front, and pulls air into the back. The only way to avoid this effect is to make the panel size larger than a wavelength of the frequency of the audio. And, even then, it only works effectively if the room dimensions are also larger than that. The wavelength of a 20 Hz tone is 50 feet. Therefore a dipole can only achieve "proper wave launch" if both the panel and the room are VERY large. And the only way to "avoid" this effect is by moving a lot of air and using active equalization to compensate for the resulting 12 dB/octave "loss in efficiency" that it causes. A normal subwoofer avoids this issue because it is able to "pressurize the room" rather than to "launch a wave into it". Since the dipole cannot do this, it has to work very hard to "launch its wave", and the effect only works well if you're sitting in the proper location. If your seating position is to the side of the panel then the wave, travelling around the edge of the dipole panel, "passes you", and you get to hear it as sound. Unfortunately, along with being impractical, that is usually NOT a good listening position for the speaker otherwise. You're MUCH better off crossing over to a normal sub at the frequencies where a dipole becomes impractical. Short answer: I agree. I have used a subwoofer since my first pair of Maggies back in 1979. The panels have limited displacement so large bass signals require large area and even then distort heavily when driven by deep bass signals. A look at equal loudness curves shows we are less able to hear bass frequencies, so deep bass (~100 Hz and under) requires 10x to 1000x the power of say a 1 kHz tone, exacerbating the problem. Adding a sub to offload the panels (applies to ESLs as well) greatly improves their performance over most all frequencies and means you can get away with (much) less power. My first sub was a DIY servo design and I incorporated an active crossover to roll off the bass at 18 dB/octave. It made a huge improvement both subjectively (to my ears) and measured (much lower distortion, greater dynamic range before the panels were overdriven, extended frequency response from the sub which went to 16 Hz before rolling off). Since the bass/midrange panels are not mechanically decoupled (isolated) the improvements definitely went well into the midrange. The design has changed somewhat since then, but the principles and improvement possible by adding a sub still apply IME/IMO. Integration is not all that difficult these days when DSP is readily available. Back then, my sub control included all-pass stages as well as the servo control and crossover circuits so I could time-align the sub(s) and panels. After that initial setup, I upgraded from MG-I to MG-IIIa speakers, but kept the sub and controller. I worked for a store that sold Magnepan and helped other customers integrate subs into their systems as well, including several Tympani and MG-20 owners who weren't sure they needed or wanted a sub until after they heard the difference. It is not just the LF extension, it is the cleaner sound from the panels, and ability to locate the sub to counter room modes, that made (makes) a difference. I still have the old MG-IIIa speakers boxed up, may pull them out again someday. My last stereo system with them used an ARC D-79 for the mid/tweeter, Counterpoint SA220 on the bass panel, and my old sub; they sounded glorious to me. They continued to serve in the HT days when I added a CC3 center and four MC-1's for surround and rear duty, with a set of Rythmik subs, before finally retiring them in favor of a set of conventional speakers. The HT system used several AVRs, lastly an Emotiva XMC-1 with Emotiva Gen1 XPA-2/XPA-5 amplifiers. I am still using the amplifiers though have changed the processor to a JBL SDP-75. FWIWFM - Don Great post! I saw a recent pair of videos posted by a YouTuber called OCD HiFi Guy who made a tour of the Magnepan factory. The videos were full of info from Magnepan employees. If someone who owns Magnepans watches those videos a sub will be in their future. Their description of how the bass and midrange panels combined to create an effectively larger bass panel was eye opening. The new Magnepan Di-Pole Subs should be really interesting. They handle higher frequencies so well I think they will supplant bass panels entirely in existing Magnepan designs. What do you think of removing the fuses for midrange panels and the ribbon tweeter in a 3.7i? Is the danger of blowing a tweeter really that great, especially if you use a sub and lower the demands on the main amp so the possibility of clipping is practically eliminated? |
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Post by audiobill on Jan 6, 2023 18:48:13 GMT -5
And sometimes you’re lucky.
Working with careful placement in my 20w x 18 h x 40d listening space, my Maggie 3.6/r speakers are about 4 1/2’ out from front wall and 2’ in from side walls.
With multiple careful measurements using REW, I’ve been able to achieve my desired target curve with no bass augmentation. Filters produced by REW are so minimal as to be unnecessary.
I try to avoid subs because I prize deep, articulate natural bass in lieu of boom boom from acoustic basses used in jazz, lowest frequency 39hz. Timbre and natural harmonics over volume.
Nor do I regularly listen much over 80-85 db, wanting to preserve my hearing, so the maggies do fine for me.
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Post by donh50 on Jan 6, 2023 18:55:24 GMT -5
And sometimes you’re lucky. Working with careful placement in my 18w x 18 h x 40d listening space, my Maggie 3.6/r speakers are about 4 1/2’ out from front wall and 2’ in from side walls. With multiple careful measurements using REW, I’ve been able to achieve my desired target curve with no bass augmentation. I try to avoid subs because I prize deep, articulate natural bass in lieu of boom boom from acoustic basses used in jazz, lowest frequency 39hz. Timbre and natural harmonics over volume. Nor do I regularly listen much over 80-85 db, wanting to preserve my hearing, so the maggies do fine for me. "Luck" often involves quite a bit of work... Which it sounds like you've done! Proper subs properly integrated are not boomy or inarticulate... My problem was my 3a's exhibited high distortion (10's of percent) in the bass region even at relatively moderate average levels (80 dB is loud to me). You've a nice big area, however, larger than most places I've had mine. But clean bass below 50 Hz (really closer to 100 Hz) can still be a challenge. I have not heard 3.6's in years now (and never the 3.7); have you done distortion sweeps in REW? Curious - Don |
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Post by audiobill on Jan 6, 2023 19:01:03 GMT -5
Yes, but don’t recall them being an issue at my typical spls of below 80 db. Of course, panels tend to not be the best for loud rawk, but I left that behind many years ago. Miles for smiles! 🥸
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Post by audiobill on Jan 6, 2023 19:33:52 GMT -5
Fyi, here's an REW 20-200 hz sweep vs target curve (w/o subs) taken from my listening position:  |
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Post by stlaudiofan1 on Jan 6, 2023 20:02:53 GMT -5
I have had Magnepan 1.6QR speakers for years for my fronts. I never cared about air movement, waves, etc. You simply need to work on positioning them. As you experiment, you learn “if I change the placement like this, it sounds like that”. They are very sensitive to placement and toe in, with very small changes giving almost drastic differences. Through the 10+ years I have owned them, I pretty much know the best positions in my room. My home theater room is 20’ x 12’, and the seating position is roughly 2/3 the length of the room back from the front wall. The best STEREO position for the Magnepans is roughly 1/3 the length of the room from the front wall and well into the middle of the room…tweeters on the outside with almost no toe in. It’s magical there, but not practical for theater, because it’s in the way of the 103” projector screen. I have 2 subs on the front wall. The crossover point that works best for stereo is 50hz, which is roughly 10hz above the speaker’s minimum rated capability. For home theater, I found that about 2 and a half feet from the front, about a foot from the side walls, more toe in and tweeters to the INSIDE works best. The crossover point that works best for integration with all the other speakers in my system is 70hz. 80hz sounds a tiny bit thin, 60hz & lower doesn’t integrate as well. Every time I listen to traditional speakers, the “cone “sound is annoying. As an example, singers sound like they have their hands cupped around their mouth when they are singing. I will always have my fronts either a planar speaker, or at minimum speakers with ribbon tweeter and mid range drivers. Attachments:
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Post by audiobill on Jan 6, 2023 20:09:34 GMT -5
Agree, tweeters outside, very little toe -in, tweeters inside,more toe-in, practically pointing at listener. Point is bass side a little closer than tweeter.
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Post by donh50 on Jan 6, 2023 20:54:34 GMT -5
Fyi, here's an REW 20-200 hz sweep vs target curve (w/o subs) taken from my listening position: View AttachmentNice response! I've a big null due to room dimensions around 30 Hz that I've had a hard time canceling with my subs (pretty close now). You are down ~10 dB at around maybe 35 Hz, about what I saw with my Maggies, and that is certainly low enough for many (perhaps most) music. I still have the old Telarc 1812, some organ music (my wife plays), like the percussives from drums and such (son plays), so wanted lower than that (and distortion that low was high in my system). Then I started down the HT hole and subs were a requirement... I was very surprised at the soundstage my current (conventional) speakers provided when I first set them up. I did not lose anything from my Maggies when seated in the MLP, driver/sound integration through the midrange was good (one of the things I found lacking in many speakers, even some "high-end" models), and gained a good octave of bass. I suspect much of that is because I have a fairly small room so sit fairly close, and it is well-treated so imaging is stable. Onwards - Don Edit: General comments on Maggies... As mentioned by everyone, they are very picky about placement, and in my case I almost invariably damped the wall behind to gain better imaging and lack of comb filtering that always drove me nuts (a short drive). I only had a large room a few times so they were usually within 2' - 4' of the wall behind, and usually 1'~3' from the side walls (though they are not picky about side walls -- panels have not much radiation in that direction). Tweeters in or out very much depends upon their distance from each other and the listener; I have had it both ways depending upon the room, but usually found tweeters inside provided the best imaging and smoothest transition to the midrange. Magnepan suggests (or did, anyway) tweeters in and toed in a little as the mid/bass panels tend to "lag" the tweeter panel a little (crossover phase). I have usually had modest room sizes so sat fairly close; in a large room, sitting further away, tweeters out can "open up" the soundstage but you have to ensure there's no hole in the middle. It is still one of those preference things. My best setup had them roughly equilateral with ~12' sides, tweeters in, and very little to no toe-in. It was also bi-amped as mentioned above with my sub centered between them crossed at 60~70 Hz. I don't remember the bass to mid/tweeter crossover; I think it was close to factory, but I used 12 dB/oct on both sides. I have run a pair tri-amped but found it really didn't help and made for a very complex integration process (especially in the days before DSP). To me the full true-ribbon tweeter was worth the cost, but smaller ribbon tweeters always seemed too "beamy" to me unless there was an array of them. I had Infinity QRS-2s with a similar array (EMIT and EMIM) that sounded good, but their planar "ribbon" drivers (really they were planar dynamics too) were unreliable -- the connections were forever needing repair, a problem they (Arnie, RIP) dealt with in later models, I think. |
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Post by fbczar on Jan 7, 2023 0:13:25 GMT -5
Fyi, here's an REW 20-200 hz sweep vs target curve (w/o subs) taken from my listening position: View AttachmentI do not see how you could do better with those measurements. Congratulations 🎈 |
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(Exaggeration I am sure but...) The problem is less clipping (though that will do it) than just playing too loudly and blowing the tweeter without realizing it, or an accidental "pop" from a failing component or user issue (e.g. tripping over an interconnect or power cord, sending a full-volume blast to the speakers, don't ask how I know this). I have been hearing users claim great improvements from strapping the fuses for years. What I know are (a) repeated blind tests have shown no difference and (b) when I was a tech strapped fuses were a great revenue stream for the repair shop. I wouldn't do it. I tried it, convinced myself I heard a difference, and then blind testing proved it was nothing more than perceptual bias. My advice is to leave the fuses in place. When Magnepan says they are "fragile" they aren't kidding.
