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Sorry if this has been discussed before.
But, how would a pair of moderately modded 3.6 (using active x-over for biamping and Mye stands) sound in comparison to a stock 3.7?
Follow Ups:
It would not be that difficult to improve the stock 3.6 XO such that the sonic result would equal or exceed a stock 3.7. In my opinion the XO difference between the 3.6 and 3.7 is of much greater magnitude than the change to foil from wire.
There's more to the crossover than the component values, though. There are changes to the way the diaphragm is tuned, visible in the photograph. There's no practical way to achieve the same effect with a 3.6.
OK - how would a pair of moderately modded 3.6 (using active x-over for biamping and Mye stands) sound in comparison to a stock 3.7?
Providing the 2-way active XO was a good sounding - and flexible - one, so you could try different slopes & roll-off points, I would suggest the result would be on a par with a stock 3.7.
But if you went to the next step - replacing the stock MDF frame of the 3.6s with a hardwood frame - I would say the modded, 2-way active 3.6 would be better.
And if you then rebuilt the internal mid/ribbon XO on the 3.6 with the sorts of components that Barry did ... it would be streets ahead of a stock 3.7.
Good luck,
Andy
It's pure speculation. The 3.7 reportedly uses flat foil (QR) rather than round wire for the bass and mid-driver. Whether this is a big advantage or not, I can't say. I would expect that foil would eliminate the problem with delamination - has anyone had their 1.6 tweeters delam? Intuitively it would seem that having the drivers designed the same would make for better integration but I don't know if having both foil is any better than having them both with round wire. Integration with the tweeter may be better with the QR drivers but I don't know that.
The other feature of the 3.7 is the use of 1st order xo's which have lots of theoretical advantages over other types of filters. The downside is a shallow slope so the drivers extend beyond the normal bounds. However the Maggie drivers have quite a good range and don't suffer from edge effects, etc. like cones, so this is a minor drawback.
Biamping 3.6's and doing some other tweaks definitely improves their already prodigous sound. Biamping is tricky but if you get the slopes and crossover correct, then the gains are significant and the sound is going to be hard to beat.
The question then remains how much bang do you get for your buck. Modifying 3.6's by either triamping or rebuilding the internal xo and biamping and building new frames and stands is going to be close to the price range of the new 3.7's. If you get the 3.7's you can push them further later on with wood frames (they cannot be multi-amped) and better crossover components.
Bottom line, you won't go wrong either way. If it were me, I would go with the 3.7's and plan on moding them down the road. OTOH when I was contemplating replacing my IIb's with to be modified IIIa's or stock 3.6's, I went with the IIIa's.
On the violin: "Heaven reward the man who first hit on the idea of sawing the innards of a cat with the tail of horse."
Edits: 03/19/12
IMO, it seems there are only 3 mods you can do to a 3.7 which are guaranteed to improve its sound quality:
1. Substitute a hardwood frame for the stock MDF frame ... which includes doing away with the staples and rigidly fixing the bass/mid driver assembly to the frame.
2. Get some Mye stands, or equivalent, to stop them swaying.
3. Rebuild the all-6dB (internal) XO with high quality parts (same values).
Undoubtedly, these mods will make 3.7s sound better. But, IMO, it remains to be proven whether, having done the above, they will sound better than a pair of fully tweaked, active 3.6s. :-))
Regards,
Andy
You could also go active on the 3.7's, if you didn't mind bringing a few wires out (or repurposing the attenuator connectors).
They did make significant changes to the tuning of the diaphragm on the 3.7. I'm not sure that the 3.6 would allow you to use single pole crossovers without compromising performance, e.g., the usual issues of dispersion/power response, power handling, and resonances.
Valid point but it seems that Mr Gunn produced a good-sounding 3-way mod using 6dB (series) XOs? At least, his customers thought so (the only complaint I've ever seen - the F111 pilot - was complaining about the woodwork, if my memory serves me.)
Regards,
Andy
As DR said, the results weren't so good, though I don't think we were ever absolutely sure that it was the crossover (the problems were in the midbass IIRC and the listening room has a big effect there).It's actually pretty hard to do a single pole crossover, because of the much higher demand it puts on the drivers vis a vis mass, power response/dispersion, IM, power handling, and resonances/breakup.
Edits: 03/20/12
Gunn's mods include rewiring the 3.x models into a 2 way. This results in an overwhelmingly big midrange.
Davy (UK) is reporting very good results with his 6 db mods to the 3.3.
The bass still has to be done in 3rd order and possibly 2nd (he dumped his behringer so can't confirm and his current active is fixed 3rd order).
Very interesting.
I was going to pass on something I just read about IV woofer crossovers on Arthur Salvatore's site, but then I read two letters from you (and one from Mmlrot1), so I figured you'd already read it.
I agree Josh, but then why did magnepan move to 1st order on the new mmgs?
I always thought it was to mess them up in relation to the 12s so that there was a reason to trade up...
Afterwards we discovered faith; it's all you need
I figured it was to save money. They also leave off the bypass cap. Also, they did redesign the MMG's tweeter when they made the change. The narrower tweeter would have a different polar response. I think the main point is that you have to tune the speaker for the crossover and vice-versa. Forex, if there's a resonance in your driver a bit above the crossover point, like the one Satie pointed to in the 3.x woofers, you have to either use a sharper crossover or change the driver to eliminate the resonance. Conversely, he was able to use the 6 dB/octave driver with his IV's because they were designed to cross at about 350 Hz and he's crossing them over lower to his Neo-8 midrange.
Here's another photo of the 3.7 woofer panels, you can see that they've changed the tuning substantially, and there's no more clamp, rather an acoustical filter made out of tuning dots. These look more like 3.5-way speakers now, with sort of a physically sliding frequency range:
http://www.avguide.com/blog/first-listen-magnepan-s-new-flagship-207-loudspeaker?page=1
This should improve power response and I think reduce crossover lobing.
Well at some stage soon, I'm going to prove it - one way or the other! :-)) After discussions with Satie, the mulleted midget and (the English) Davy, I intend to substitute 6dB boards into my active XOs ... except that I'll keep the current 18dB bass LP slope.Regards,
Andy
Edits: 03/20/12
Now, if we could only get you properly set up to measure the response of the Frankies before and as you make those changes!
I am only interested in how they make me feel , after the change. :-))
So I'll substitute the new XO board having:
* 6dB mid HP
* 6dB mid LP, and
* 6dB ribbon HP
... and leave my existing 18dB bass LP board in place. This will require me to flip the ribbon polarity so that it's now the same as the mid (which is inverted, relative to the bass). Getting the ribbon connected in the same polarity as the mid is the only reason for doing this change, IMO - and then I'll start listening to all my favourite pieces of music, to see if I like it better. :-))
Measurements I'll leave to engineers like Davey! :-))
Regards,
Andy
Yes, the "feel" is key.
Being a possessive bastard, I tend to measure after a change that makes me feel good. This helps to insure that I can replicate that "feel good" experience later. It quantifies a few things for reference; as a practical mix of the subjective and the objective. It often also suggests ways to fine tune for a better feel.
LOL! Davey will soon show up and set us both straight. You have a couple of intentions listed there that should do nicely to ruffle his engineering feathers.
Anyway, one of my favorite bi-amp PLLXO configs has both MMG drivers in the same polarity, in 1st order. To do so and still retain the same tonal personality (while adding other attibutes), the tweeter high pass cap has to be different, and the level adjusted.
If I measure this vs my other 1st order xover version with the mic, I'll get the same pretty flat response. They virtually overlap. One inverts electrically, the other doesn't and yet, tonally, they are the same. The difference is in the soundstage each one projects. I am guessing that it is a phase-related thing. There are caveats but that is another story.
OTOH, my most accurate (to me) bi-amp xover config is one that pretty much mimics the original 1st/2nd order slopes; what these old-version MMGs came with. This is what I use most of the time.
So, I have 3 PLLXO configs that I can live happy with. If any of them starts sounding wrong, a quick mic reading may suggest that someone messed with the system...or, more likely, confirm that I just had too many beers. : - ))
Interesting to read that.
Was it you who posted about the audience applause & whistling at the beginning of HFOT "Hotel California" coming from above & behind ... and I then posted that this didn't happen with my setup?
If so, that's the sort of result I'm hoping will be produced by my mids being in the same polarity as my ribbons, with the 6dB XO.
Regards,
Above and behind usually has to do with high directionality, the absence of room reflections, or suppression of interaural crosstalk, as well as *relative* phase between the two speakers (being exactly centered, and also maybe having any early reflections timed right).
Well, the impression I got was that the LP recording that you have is of a different Hotel California session. Even if it is the same, it may be that the LP renders it differently.
Luckily, there's an easy way to find out. Let me not clog the thread...check email in a few minutes for an idea.
Hey Andy,
I thought you had to reverse the polarity even on the 1st order slopes. Well the current mmgs have the polarity reversed but have 1st order slopes.
Neo did his best to explain it but I didnt FEEL like getting it :)
Afterwards we discovered faith; it's all you need
My only experience with this comes from simulating many (certainly scores ... and maybe over 100) Maggie XOs in lspCAD.
I have found that the "normal" situation with 6dB XOs is that the drivers need to be connected with the same polarity (and this is what I see as the big advantage with 1st order slopes ... which outweighs the problems associated with increased driver overlap. etc) - otherwise a big hole opens up at the XO point.
But every now and again, I found that a particular combination of LP & HP roll-off points required the tweeter to be flipped, to get rid of the hole.
So have no idea what causes this behaviour - simply that it happens. Maybe Davey could give you a more technical expose?
Regards,
Andy
For a symmetrical 1st order crossover (same fc), polarity is irrelevant except perhaps to those freaks who can hear absolute polarity. Let's assume the phase at frequency x for the LP is 0 deg., then the phase for the HP is 90 deg. and the difference is 90 deg. Inverting the polarity on the HP makes it -90 deg. and the difference is still 90 - same difference. Now for asymmetric 1st order xo's the phase difference are not the same (not 90 deg) at all frequencies so inverting will result in a different phase difference. If the fc are far apart, then one may get the drops in the output and inverting may correct this.
As an example here is a bode diagram for the MG-IIb. The fc's of the LP and HP are 2 octaves apart and you can see the drop out for the same polarity that flattens with the inversion.
And here is a Bode diagram for a symmetric 1st order XO that crosses at the same frequency. Note the output only shows as a white line (the magenta line coincides and is obscured). The output is dead flat and if you look at the phase plots they are are always 90 deg apart.
On the violin: "Heaven reward the man who first hit on the idea of sawing the innards of a cat with the tail of horse."
Maybe...
Hey Andy,
I think your memory is a bit off.
Anyhow here is a bit from the review:
So am I happy? No, I would have to say this was not a forward step for me after listening for the past couple of months and tweaking for the best sound compromise I could achieve in my room. The stock 3.6R's had a more "seamless" sound with cohesive soundstage and balance between the frequencies. They had to be "pushed" more for their best sound, but could be listened to for hours as reasonable high volumes levels. The Magnestand 3.6R's are better at conversational levels, but I believe the stock 3.6R is better everywhere else. I have a lot of $ invested and cannot afford to sell them at a loss, so I will apply my own expertise and see if I can get them a little more balanced to my taste. This is not the first step backward I have taken in 42 years and it won't likely be my last. It's part of the journey.
See the whole post below and I thought that Saties post about 1st order crossovers was interesting. And I dont recall another 3.6 owner with this mod, but we have seen how memory is a funny thing so I could be wrong :)
Afterwards we discovered faith; it's all you need
I read through the posts since you so thoughtfully provided the link and I have to wonder.. PG started doing mods initially on SMGs, MG1s, and the smaller two way Maggies and I believe that these speakers come tilted back away from the listening position and are tilted away on his Magnestands. So, I was wondering if his mods to the 3.6Rs included tilting the speaker back like is done with the smaller models and if so, if this might lead to the gaps or holes in the soundstage that Varkdriver was describing.
I have no idea, but I was just curious.
Good day
His system was updated 3 months later and contains this comment:
"Magnestand mod is growing on me, but the jury is still out"
Hi SB,
You are right, I had missed that.
But I dont know if that is such a ringing endorsement since that line is listed under system weaknesses !
IIRC Waz went through that with his modded speakers. It took him a while to get used to them and then he did, but ultimately went back to stock.
It will be interesting to see what Andyr concludes.
Afterwards we discovered faith; it's all you need
Hi. DR
In regard to the inmate with the Gunned 3.6's---- IIRC, he specifically changed-out his pre-amp to acquire a pre-amp with TONE CONTROLS.
old guy
A tone control to counterbalance the one built into the speakers!! Not that is so music lover it is crazy!
Hey Old guy 42!!
Jben and I thought you passed or something. We were at this club he takes me to. It is the same old thing, some cuban band is playing and the drinks are flying and then he smiles and takes out his papers full of measurements. My eyes glaze over and I look around the room. But last tuesday when I looked, I saw this old dude slumped over and drooling. "Holy crap, its old guy 42", I said.
Jben looked perturbed and grabbed another stack of papers. These were drawings of faces. Then he said, "Close. That is old guy 43. 42 probably passed making that MM842R cable. Now look at this graph Dawnrazor"
I have been thinking about your config of magwire. The "old guy twist" i'll call it. I think it might make a great interconnect. If you give me a while I will make such an IC and maybe a few other configs. I can send them to you and you can see which ones you like. I dont really have any rca connections these days so those extra tips I have are kind of useless. I was thinking too that we could send them to some other inmates and see what they think as well. Would 3 ft be enough?
Afterwards we discovered faith; it's all you need
Hi. DR
First of all---My condolences to 43's family.
Second of all--My apologies to the OP.
As I read your account of the evening at the club with Jben....At the table, I pictured you as Flash Gordon and Jben as Dr. Zarkoff. Then, Dr. Zarkoff tells Flash.."Pay attention, this is important!!! And forget about a lap-dance, Flash".
Your story was truly, funny as hell!!!!
I took your advice and made a second pair of speaker cables and wired it shotgun. Still, great clarity, a bit fuller, and the best, so far, imaging.
In regard to ic's, you flatter this old, tech. challenged, guy with "old guy twist". I have read pros & cons in the cable asylum about star-quad ic's. I think I would consider Al's idea about the Highwire RFI coils. Only 10 bananas at Music Direct. As far as construction goes, I was going to put 5 runs of 100% cotton yarn in the drilled holes of the wood pieces. Then attach the 30 ga. & twist and then wrap with teflon tape and then slide on the Tech Flex. I was going to wait till August to do this, and I would be very interested in knowing how you would build the ic's. Also, I would be super-happy to have an ic made by you!!! I just need a 24"er for my Thomas Edison..errrrr my CDP.
I think the Star-Quad works for my speaker cable because of the close proximity of my amp. to the aux. AC outlet that I tried to hide from my wife.
I also think that I took up enough of your time. Next time...Listen to Jben :-))
Take care....old guy
LOL! You did leave out the part where you stealthily left me hanging with the tab. Serves me right for mixing with too smart folks.
Hey, last night I was making preparations for an upgrade to the Stixbees. The MMGs wound up on their original stands, fully leaning back and with no Stixbees...just the Razoring. I had never heard them this way (slanting back + Razoring, no frame reinforcement). So, it was a chance to hear what the rest of the mods do with just your tweak, on "full slanties".
It was rather good...actually, surprisingly good. I might as wll mention that the Razoring benefits have held just fine over the almost 2 years since I installed the tweak. You can now increase the warranty to 2 years and charge a little more. : - ))
I did make a few quick frequency scans just out of curiosity...not that you would care for that kind of thing, lol!
I was waiting for you to show up, Andy. Even if I agree, mine is not a fully qualified opinion when it comes to large frames.
I might as well add that the next experimental upgrade to my MMG has "ulterior motives". If the new wood works as good as I hope, it may be the my choice for frame reinforcement in case a pair of 3.6s suddenly fell on my lap. One never knows when, but one prays...LOL!
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