Followup-Magnepan 1.7s in a 10x13' dedicated room?


Well I brought the demo MG12s home from the dealer for the weekend and they actually worked very well in my small listening room. Everything I love about Maggies was there with a couple of surprises. First, I ended up with the speakers fairly close to the side walls, though the walls are treated. Second, I obtained the best imaging with the tweeters on the outsides. I assumed they would work better on the insides considering their close proximity to the side walls. The sound stage was wide, deep and well defined. I was able to hear and feel bass in the low 40s, which was another surprise. I give credit for that to the 4 inch thick bass traps I made myself. It's amazing what those have done for a room that literally sucked bass out of the room without them. Some recordings were a little bright, but I think I could remedy that with resistors applied to the tweeters. The dealer didn't supply with resistors to take with me. The MG 12s worked so well in fact that I'm seriously considering the 1.7s. Especially since I hope to be moving to a larger room in the future.
linesource
Zd, I used this technique with both the 1.6s and the 3.7s. This technique does not roll off the high end, which would more likely occur by turning or tilting as you suggested. What this technique does is reduce the time smear from an individual driver to the extent possible, but it certainly does not reduce it to zero. The speakers sound better, but it does not really change the tonal balance to make them more or less bright or warm. If you think about how this plays out with, for example,the ribbon, when the panels are tilted to achieve a perpendicular from the mid point to ones ear, then the distance from the top of the ribbon to one's ear and the bottom of the ribbon to ones ear is equal. This would give the lowest total amount of smear. On the other hand, if the panels are tilted back, then the bottom of the ribbon may be 6 -8 inches closer to one's ear than the top, and each point from top to bottom is a different distance from one's ear. This arrangement gives the maximum time discrepancy possible. In practice, I found this improvement to be more significant with the 1.6s, but it also helped with the 3.7s.

Bombaywalla, I take it you are not a big fan of Maggies!

Obviously, I draw a different conclusion than you do, while conceding that the unique Magnepan design brings with it some unique compromises. Those you have heard may not sound right to you, but Magnepan has a lot of fans who are not tone deaf knuckleheads, who would express a much different conclusion. Magnepans can sound heavenly in the right room with the right ancillaries.

Sometimes, the problem is the recording. Some times, the problem is the room. Sometimes, it is the wrong speaker for the room, but would work well in another room. I have recounted several times in this forum a concert experience from the late 80s, listening to an Isaac Stern recital. If I had closed my eyes, I would have said this is the worst screeching ear-bleed inducing bad digital recording I have ever heard. It was a world class violinist, playing a superb instrument, but unfortunately, it was the wrong seat in the wrong hall for that violinist and violin. It sounded really really bad. I don't know that it had anything to do with time coherence. Later that year, I heard Itzhak Perlman from the same seat, and his playing was sweet as honey.

Likewise, any room not constructed as a perfect sphere or an anechoic chamber is going to reinforce and diminish certain frequencies. This has nothing to do with speaker design. Treating a room to reduce unnaturally reinforced frequencies makes sense to me.

As I said before, if there were a perfect no compromise design everyone would use it and life would be simple.
" On the other hand, if the panels are tilted back, then the bottom of the ribbon may be 6 -8 inches closer to one's ear than the top, and each point from top to bottom is a different distance from one's ear. This arrangement gives the maximum time discrepancy possible."

I was thinking pretty much the same thing with regards to the bottom of the ribbon moving toward the listener and the top moving away. I'm just questioning the why of it. How do you know its a time coherence issue, and not a roll off/freq. response issue? Magnepans do measure poorly in that area. I don't know for sure, so you may very well right. I know freq. response can be measured. Is it possible to measure time coherence?
Zd, I have no way of proving the improvement is time coherence. The person who suggested this to me explained it that way, and it made sense, so I just accepted the statement.
With the right equipment, one could evaluate any change in frequency response, but all ll I have is my ears.
Bombaywalla, I take it you are not a big fan of Maggies!
Brownsfan, I wouldn't put this strongly. I've heard a couple of Magnepans - one was at a friend's house - I believe it was the MG12 - they were quite narrow & not very tall. He was using an Anthem power amp. It was very nice for vocals but lacked any dynamic drive to get-up & boogie. Another time I heard a MG1.6 at a dealer's place driven by a Musical Fidelity integrated amp & an iPod dock for the front end. Very nice sonics. I enjoyed that brief session. In another room this same dealer had the 20.6 full ranges driven by Rowland Model 10 amps but he was such a stick-in-the-mud & refused to give me a demo because I hadn't set up an appointment!! :(
No, I wouldn't say that I do not like Magnepans but I recognize their severe limitations & their inherent design flaw & decided that I did not want to partake in such a speaker.

.....Magnepans can sound heavenly in the right room with the right ancillaries.....
...Sometimes, the problem is the recording. Some times, the problem is the room. Sometimes, it is the wrong speaker for the room, but would work well in another room.....
Brownsfan, these are exact excuses one has to make when one is dealing with a flawed design loudspeaker. When a loudspeaker is properly designed, it works well in any room & works even better in rooms that are correct for its size & correctly treated. Of course, common-sense has to be exercised - I cannot put a Wilson Maxx into a 10X10X8 room & hope to make it sound its best.

At any rate, this discussion with you is NOT to argue with you or be contentious; rather, it is to point out the loudspeaker design flaw & as a result all the tricks you need play to minimize (but never eliminate) an inherent design flaw. If all you dedicated Magnepan users understood what time-coherence is & what its importance is to music playback, you could go back to Magnepan & demand it from their speakers. The manufacturer will make what his clients ask for/demand lest he should go out of business. In such a case both the Audio industry & the user-base would much better off & maybe the following of Magnepan would grow even more.....
Is it possible to measure time coherence?
Zd542 (Threads | Answers | This Thread)
yes, Zd542 it is very much possible to measure time-coherence. For example, look at Fig 4, Fig 5 of the Quad ESL63 as measured by Stereophile & read the text immediately below Fig 5:
http://www.stereophile.com/content/quad-esl-63-loudspeaker-measurements

I don't know if you remember Meadowlark speakers? The owner/designer was Pat McGinty & he built time-coherent loudspeakers. He wrote a very easy to read article about understanding time-coherence & its importance to music playback thru loudspeakers. Here is the link.

http://www.patmcginty.com/Dbench2.htm

If you don't want to read the full article, take a look at these 3 pages that have animations (hope you have Adobe Flash installed):
http://www.patmcginty.com/Dbench8.htm
http://www.patmcginty.com/Dbench9.htm
http://www.patmcginty.com/Dbench10.htm

These animations should make the importance of time-coherence clear to you.

You'll also note that almost 99% of the speakers in the market have the step-response shown on page 10. And, you can troll the various forums to read all the issues people have with such speakers -
just the right ancilliaries,
just the right recording,
just the right cables,
just the right room size,
just the right recording,
just the right music genre,
just the right toe-in
& the list goes on & on.....
it all goes away once you have time-coherent loudspeakers because the speakers are not further distorting the music signal coming down the pipe from the electronics.