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Magnepan 2.7/QR image / focus issue

75.142.228.102

I have a pair of Magnepan MG2.7/QR speakers. I am the original owner and purchased the speakers around 1998. I have made no modifications or upgrades to the speakers. My listening level is low to mid volume. I have never had a fuse blow in either speaker or any amp used to drive the speakers.
My issue is my 2.7 speakers do not image as well as they used to or as I remember them. When I swap in my pair of MMG's the speakers are spot on in their focus and deep soundstage imaging but missing the deeper bass and presence of the larger speakers. This listening test is immediate and I had a second pair of young ears agree with the results.
I moved a short while ago and this is the second home that I have compared the MG2.7's to the MMG's with the exact same listening results. I do not hear any buzzing or slap from the 2.7's. When I pull the fuses I can hear the tweeter and midrange drop out and when I replace the fuse the mids and highs return so my belief that all drivers are producing some level of sound. Does not appear to be a left or right speaker issue as the overall sound quality is the same from both speakers. Any suggestions welcome thanks.

Follow Ups:

RE: Magnepan 2.7/QR image / focus issue - gmack 20:57:30 12/19/16 (0)
I floated the idea of capacitors going bad several months ago when I called Magnepan to order a box for my MMG's. The woman I spoke to in service had not heard of that being an issue.

I will inspect the panels for delam and measure the resistance on the drivers as well after the holidays. thanks for your inputs.
RE: Magnepan 2.7/QR image / focus issue - Satie 00:56:06 12/19/16 (7)
Have you changed amplification?

Try measuring DC resistance between the terminals:
The mid and tweeter are both in series with caps so can not be measured from the fuse or main terminals, but only from within the speaker.

If the sound is getting over ripe and bassy and the top end and mid are getting underpronounced it may be due to corrosion of the wires which tends to raise resistance and lower output. They are 30 years old. My mids had that problem at 22 years old but they were living in the SF bay area with salty sea air before I bought them. The wires will eventually get too thin and break. You can deal with it yourself or send them to magnepan for repair.
If you are considering doing the repairs yourself then you can use Mart's recipe for modifying the crossover with higher grade parts.
- http://www.audioasylum.com/cgi/t.mpl?f=mug&m=66328 (Open in New Window)
- RE: Magnepan 2.7/QR image / focus issue (update) - gmack 16:18:00 01/12/17 (6)
  Ok I started testing. I pulled the sock off the right speaker. I disconnected the spade connections to the woofer, mid and tweeter so the crossover would not affect the pure resistance readings.
  Tweeter 4.1 ohm
  mid 4.2 ohm
  woofer 4.2 ohm.
  
  These readings seem to be the same (allowing for slight meter difference) as those listed in the speaker diagram attached.
  
  No delam was found in tweeter or mid wires. There is slight delamination on the woofer. Maybe up to an inch on bottom but not all loops and up to 1/2 inch on top again not all loops. There was only one woofer trace with a delam in the middle and that wire was delaminated about 3 inches where the vibration button is.
  
  The crossover only has one bipolar cap and that is on the woofer 50uf. would not expect the film caps to go bad on the tweeter (solen) and mid (elpac).
  
  I hope to pull the sock off the left speaker and insepect it soon.
  - RE: Magnepan 2.7/QR image / focus issue (update) - gmack 10:23:25 01/15/17 (3)
    Inspected the left speaker. measured resistance on all drivers and all good. less delam (almost none) than the right speaker. I will make one change at a time to the crossover when the parts arrive starting with the bipolar 50uf caps.
    
    Question has anyone heard of the magnets degrading with time?
    - RE: Magnepan 2.7/QR image / focus issue (update) - Satie 14:36:41 01/16/17 (2)
      Not really an issue with these types of magnets. It would be an issue with AlNiCo that needs occasional remagnetization - at least with the old formulations. Which is why they fell out of favor, well that and cheap high power SS amplifiers that made the high cost of stronger magnets unjustifiable..
      - RE: Magnepan 2.7/QR image / focus issue (final results) - gmack 19:08:15 01/26/17 (1)
        
        In Reply to: RE: Magnepan 2.7/QR image / focus issue (update) posted by Satie on January 16, 2017 at 14:36:41
        
        First thanks to all who posted. I did three things that improved the sound. The first was I replaced the bipolar 50uf on the bass with a dayton film of same value. This cleaned up some of the sound but was still lacking in dynamics. The second was, and I am still in testing phase, is I bypassed all the capacitors with a 10uf MRO-2 russian PIO capacitor. I am not saying these are the ideal values but simply what I had on hand. Much more of a dynamic speaker with more detail at every frequency range. I will by trying other values and caps to see what results I can get. Third, If you remember I compared my 2.7QR with my MMG's and believed that the MMG's focused better. I moved my 2.7/QR tweeters to be in the same location as the MMG's tweeters. I believe this improved the focus of the 2.7's. Both speakers tweeters outside slight toe in. In the past when I swapped speakers I would align on the inner part of the speaker, but the tweeter was on the outer part of the speaker. I hope this information is useful to someone else who is going through a like issue.
        
        RE: Magnepan 2.7/QR image / focus issue (final results) - Satie 22:23:31 01/27/17 (0)
        
        In Reply to: RE: Magnepan 2.7/QR image / focus issue (final results) posted by gmack on January 26, 2017 at 19:08:15
        
        That is a bit too big of a bypass, you actually lowered the crossover point a bit. But if you like it then it is fine. If it is practical, then try to match the values of the original crossover more closely when you include the bypass cap so that you are not departing too far from the original design.
  - RE: Magnepan 2.7/QR image / focus issue (update) - Satie 21:34:52 01/12/17 (1)
    Since you have the speakers open then outside the delam you spotted, the other ageing related shift in performance is often the decline of the bipolar electrolytic cap in the crossover. Even if it is still ok now, I would not expect it to last that much longer. Get a film cap to substitute. Does not have to be expensive. It may be the culprit in your imaging problem.
    - RE: Magnepan 2.7/QR image / focus issue (update) - gmack 08:35:38 01/14/17 (0)
      I am pulling the staples on the second speaker. I have ordered film capacitors to replace the 50UF bi-polar caps.
a wide guess but - Green Lantern 19:53:58 12/18/16 (1)
perhaps the capacitors are going South on you. I'd recommend you give Magnepan a call and see if Wendell has any suggestions.

Edits: 12/18/16 12/19/16
- sorry- meant 'wild' lol..nt - Green Lantern 20:15:52 12/19/16 (0)
RE: Suggest you ... - andyr 00:06:14 12/18/16 (10)
contact 'Peter Gunn', as he has a pair of 2.7s and loves what they do.

Andy
- RE: Suggest you ... - Roger Gustavsson 02:18:24 12/18/16 (9)
  Is his pair not converted to two-way?
  - RE: Suggest you ... - RickeyM 20:24:36 12/20/16 (6)
    I don't know about 1.7's but the 2.7QR's were 3-way's wired up to use a 2-way crossover.
    - RE: Suggest you ... - Roger Gustavsson 22:31:07 12/20/16 (5)
      "At this time I am not going to reveal what we did or how we did it, but we were able to make a 2 way out of it without removing anything."
      
      The whole story, http://www.integracoustics.com/MUG/MUG/tweaks/peter_gunn/2.7.htm
      - Potatoes, potatos. - RickeyM 15:29:28 12/21/16 (1)
        
        In Reply to: RE: Suggest you ... posted by Roger Gustavsson on December 20, 2016 at 22:31:07
        
        The woofer, mid & tweeter panels are still there. The mid and tweeter are (with the help of the x-o) integrated to work as a single driver
        
        RE: Potatoes, potatos. - Roger Gustavsson 23:02:12 12/21/16 (0)
        
        In Reply to: RE: Potatoes, potatos. posted by RickeyM on December 21, 2016 at 15:29:28
        
        That is a really strange 2-way! Such a wide "tweeter" must be very directional.
      - RE: Suggest you ... - Davey 07:43:56 12/21/16 (2)
        
        In Reply to: RE: Suggest you ... posted by Roger Gustavsson on December 20, 2016 at 22:31:07
        
        Classic Peter Gunn. Paragraph after paragraph of silly rhetorical nonsense and zero real information. How does anybody take this guy seriously?
        Regardless, the OP noted his 2.7's did, in fact, image well at one time. It shouldn't take a modification/redesign to recapture that. Some aspect of the speakers has deteriorated and is probably in need of repair.
        Dave.
        
        Edits: 12/21/16
        
        RE: Suggest you ... - RickeyM 15:22:49 12/21/16 (1)
        
        In Reply to: RE: Suggest you ... posted by Davey on December 21, 2016 at 07:43:56
        
        "Classic Peter Gunn. Paragraph after paragraph of silly rhetorical nonsense and zero real information. How does anybody take this guy seriously?"
        Because the end product speaks for itself.
        "Regardless, the OP noted his 2.7's did, in fact, image well at one time. It shouldn't take a modification/redesign to recapture that. Some aspect of the speakers has deteriorated and is probably in need of repair."
        Of course, you are correct. What can I say, we got a little carried away :)
        
        Edits: 12/21/16
        
        RE: Suggest you ... - Davey 09:37:05 12/22/16 (0)
        
        In Reply to: RE: Suggest you ... posted by RickeyM on December 21, 2016 at 15:22:49
        
        Is turning the 2.7 and 1.7 speakers into bastardized two-way designs because you don't understand how they work considered good end-product engineering??
        
        Regardless of the end-product, the silly rhetoric is not appropriate from a "manufacturer" who, I assume, wants/wanted to be taken seriously.
        That 2.7 post is now nearly ten years old and I gather the number of magical 2.7 revamps he performed could be counted on one hand. Is that a successful end product??
        
        Dave.
  - I believe it was 1.7's he converted to two-way. nt. - MWE 10:07:27 12/18/16 (0)
    nt.
    "The thought that life could be better is woven indelibly into our hearts and our brains" -Paul Simon
  - RE: Don't think so, Roger but I haven't discussed them with him for a number of years. nt - andyr 03:38:09 12/18/16 (0)
    .

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