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Speaker Position Problems Magnepan 20.7's


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I have a DSP for the subs - DSPeaker Antimode 2.0 and it works well to manage the subs and room modes.

My objective here is to try and find the right position for my Maggie 20.7's without a sub because I would actually prefer not to use them.

I'm also trying to achieve this without expending more money and adding to the complexity of the system.  I have a very strong slant to the KISS principle.

 

I'm hoping the combined knowledge of others may lead me to find a good speaker position.  So far I'm very grateful for the suggestions, so I try them (if possible) and have made progress.

I can now see that an extreme toe in position addresses some of the problems so I'll need to try that amount of toe in on all the positions in my grid to see if there is a spot where the frequency response improves further.  It may be incremental but that's the only way I know how. :)

Edited by Bilbo
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I do understand your desire to maximise your Magnepans and minimise (or not use) your subs.  I had the same intent for my SGR Audio CX3Bs, but MSO (Multi Sub Optimiser) did such a good job of integrating the SVS subs in my untreated family room that it became a non story.  MSO flattened the bass response way way better than what I tried with REW.

 

MSO gives you the ability to determine how much influence the subs have on your setup by constraining the subs gain and the crossover.

 

Given that you know REW, why not try MSO (which is free)?

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Because I run a HDD direct into a SOtM SMS-200 then into my DAC.

I prefer the sound compared to running it from my PC via Ethernet.

I might try MSO later down the track but my focus is on cracking the code of my listening room.

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Bilbo,

 

the boing in the bass is a harmonic much higher than the modes you are trying to sort.

Slam, often felt with drum kits, is also a harmonic around 8kHz !  Nothing to do with bass.

You can toe the speakers as much as you like, it will make minimal difference to bass. Bass is "the room"..

You are fighting the room dimensions. Work with them, learn to love them...

Move the mic around the room, find several locations that measure bass well, then decide which of those possible listening

positions allows the main speakers to be moved to an isosceles triangle. (My isosceles is v close to equilateral).

 If it can't be done, it can't be done, you will never get the flat freq response, like 98% of everyone else's systems.

 

Edited by Nigel
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9 minutes ago, Nigel said:

 If it can't be done, it can't be done, you will never get the flat freq response, like 98% of everyone else's systems.

 

 Quite true but I haven't exhausted all possibilities yet.

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Hi Bilbo, just found your thread...

 

As soon as I saw your schematic, I said " turn your system round".

I still own Maggy 1.7's with twin SVS sealed subs...then upgraded to Sanders Sounds 10c with twin Sanders amps and a DEQX hp4.

It took  2 years, a house move, a room tear-down and lots of Superchunk traps but finally I am ecstatic! But that is another story.

The DEQX is a wonderful piece of kit, but I hear you re. $$$. Now Roger Sanders likes DSP gear, but never offered the DEQX in his "kit" as it moved him into a different market. He stuck with Behringer gear for quite some time. His latest 10e offering includes combined xover and DSP machine and I was so curious I search for a long time to find it. He offers a DBX Venu360.  http://dbxpro.com/en-US/products/driverack-venu360 Worth a ponder, perhaps.

Also, Roger Sanders encourages an asymmetrical setup...Dipoles largely remove side and ceiling refections and he reasons asymmetrical bass causes asymmetrical nulls and we wont hear that as much.

Oh yes, I have 2 friends with 20.7s. 1 built stands out of car engine hoists !!!!! and the other bought stands off Bill Mclean in East Gosford. NSW. Both grip the wood cheeks to at least 1/2 way up. And elevate. And tilt. All good, IMHO.

Of all the dipoles I have owned, I have always tilted forwards, never back. Same with the current set up. Square up to the ear.

Phil

 

Edited by smiledon
spelling base to bass
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I thought long and hard about which way to orient the system when we first moved in two years ago.  I did some basic REW sweeps with the system the other way round but the peaks and dips were more accentuated so I settled on the current orientation.

If I can't achieve a reasonably smooth response below 400hz then I may have to resort to full range DSP.  But not just yet - more position & toe in moves to make before the white flag gets raised.

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  • 3 months later...
On 22/06/2017 at 12:06 AM, Bilbo said:

I thought long and hard about which way to orient the system when we first moved in two years ago.  I did some basic REW sweeps with the system the other way round but the peaks and dips were more accentuated so I settled on the current orientation.

If I can't achieve a reasonably smooth response below 400hz then I may have to resort to full range DSP.  But not just yet - more position & toe in moves to make before the white flag gets raised.

@Bilbo Just wondering if you've achieved any improvements recently? Clearly you have a difficult room shape to deal with. I am just going through a similar process with 3.7i's in an irregular room space with some unusual wall geometry, Particularly looking at getting the bottom end right, mids and hf are already excellent.

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32 minutes ago, mjs said:

@Bilbo Just wondering if you've achieved any improvements recently? Clearly you have a difficult room shape to deal with. I am just going through a similar process with 3.7i's in an irregular room space with some unusual wall geometry, Particularly looking at getting the bottom end right, mids and hf are already excellent.

Yes the mids and hf sound wonderful - it's just that pesky region below 300hz that the issues occur.

 

I've taken a radical approach just yesterday by giving the "Limage" setup a go. I was expecting it to sound totally weird but it's not that bad.

I haven't got it set up properly yet because it will involve some furniture moves to facilitate the 40% position plus the listening position closer to the back wall.

It certainly gives a wide & deep soundstage plus the bass is enhanced but the imaging is a bit off.  I'll post more once I find the "Focus" point in the room as per the setup recommendations.

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On 9/28/2017 at 7:55 AM, steven365 said:

Why not try some of the diffusers that I’m selling in classified section? I’m using Maggie 1.7i and these diffusers really help open up the sound stage and smooth out the highs : )

Thanks for the offer but I already have diffusers and absorbers through the room.  My problem is with the actual dimensions of the room and the resulting modes.

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  • 1 month later...

From your initial freq sweep in that room the 1.7 is operating nicely in the more audible 40hz bass umph region vs the 20.7 in less desirable 70hz region, translating to what you are not happy with. 

 

The speakers on the narrow end of the room with only 4m odd width is not enough for any panel speaker unless a narrow one, the Magies are too big in width each with not enough distance to side wall and your listening position, based on your first illustration, is too far away and not forming the recommended equidistant stereo triangle. 

 

With the listening chair out in the middle of the room there is less bass reinforcement and in a suck out bass zone. Try re-orienting speakers to the right wall 3m apart (inner edge of speakers) with toe in so tweeters fire 10cm wide of ears, tweeters on the inside, with about 2m to left corner or similar in another part of the room, speakers 1m from rear wall and listening chair against opposite wall to get rear wall bass reinforcement. This will put you in a 3m equidistant listening triangle that should get ideal imaging plus wall bass reinforcement behind listener. If the 3m distance is not enough because the speakers sweet spot is further out, then relocate to the largest part of the room to achieve the stereo triangle larger than 3m.

Edited by Al.M
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Well the Maggie 20.7's are certainly a wide speaker and giving them room is essential.

I did consider the alternative sideways layout but I don't think the Maggies sound as good if you have to sit close to the back wall.  I have tried the equilateral triangle layout which works reasonably well but I find I get a better soundstage size with a bit of extra distance to the listening position.  To my ears that helps the soundstage take on life size proportions for instruments and vocals.


At the moment I am trying quite a radical layout with the panels almost 1/3 into the room and the listening position 3/4 of the way into the room.  The interesting thing is the extreme toe in.

The panels are at almost 45 degrees to the side wall and only 300mm from the wall.  The panels are focused about 1m in front of the listening position. The distance between inside edges is 2.5m.  This results in minimal first reflections when viewed via a mirror as you mostly see the narrow side of the panel, plus, all other lateral reflections are at least 6ms behind.  The rearward panel excursion reflects off the side wall and then into the front wall before traveling onward to the listening position.  I shall give this position a bit more time as it does sound very good.

I'll put some REW graphs up soon.

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Chair against wall will definitely increase bass and doesn’t affect imaging in my setup. 

 

Panels at 45 to side wall crossing in front of listener is very weird. Tweeters should be on inside normally. 300mm to side wall is normally to close. What you are trying to do is fit a very wide panel speaker into an odd narrow and long room, but the option to try is position speakers against the longest wall, i.e 90 degrees to current setup. No harm in trying to confirm or discount that unless it totally upsets the furniture layout functionality.

 

Speakers on the narrow end of a narrowing long room is not good in my experience.

Edited by Al.M
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As I previously said, I used the long wall layout (in my previous house) but front and rear wall reflections were a problem due to proximity/boundary effects.  I do have the tweeters on the inside at the moment but that may change.  The problems created by the close proximity to the walls were worse than the ones I'm trying to deal with in this case.

As you say - this setup is quite weird (to me also) but strangely enough it works quite well.

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  • 2 weeks later...
  • 1 month later...

What a magnificent room!
How does it sound with the speakers where they are, just with less toe in?
I’m on an iPhone so tricky (for me anyway) to go back and review what remaining issues you’re looking to solve?
I bet it all sounds pretty damn good now!
Mike

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I have slightly reduced the amount of toe in but the majority of the back wave still hits the side walls before being reflected and partially absorbed by the front wall.  This provides a lot of depth and width to the soundstage.  If I reduce the toe in further then I start to get a slight rise in the frequency response between 1k and 3k.  This creates a slight glare in those higher frequencies that is unnatural to me.

I’m hoping to get some measurements done during the Xmas break and I’ll post them for comment.  Overall it sounds pretty good at the moment but I think I can get it better with more experimentation.  It will be good once I no longer have to move the speakers that’s for sure!

Edited by Bilbo
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5 hours ago, DMax said:

Have you tried having the tweeters on the outside?

 

No, Maggie ribbons need to be clear of the wall - hence Bilbo set them up as he did.  (And, the way it is, he gets side-wall reinforcement of the bass.  :thumb: )

 

Andy

 

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No, Maggie ribbons need to be clear of the wall - hence Bilbo set them up as he did.  (And, the way it is, he gets side-wall reinforcement of the bass.  :thumb: )
 
Andy
 
Really? I always have the tweeters on the outside and sound much better to my ears with wider soundstage [emoji14]
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38 minutes ago, DMax said:

Really? I always have the tweeters on the outside and sound much better to my ears with wider soundstage emoji14.png

 

Just read this from website:

 

"Once you have located the best position for the speakers and your chair for bass performance, separate the speakers by 50-60% of the distance from your chair to the speakers. For example, if your chair is 10 feet from the speakers, move the speakers 5-6 feet apart. Now, move the speakers apart in increments of 3 or 4 inches at a time, listening carefully at each position. At some point you will start to hear two separate speakers instead of a stage effect or continuous image. When this occurs, your speakers are too far apart. Begin moving the speakers back in small increments until you notice a point at which you achieve one cohesive sound stage.

Depending upon the acoustics of your room, the imaging and sound stage may be better with the tweeters on the inside for listening only in the "sweet spot". For a larger audience or listening off to one side, tweeters on the outside will keep the image centered for those listening off-axis."

 

manual_30.7_001.jpg

 

Confirms your thoughts

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49 minutes ago, DMax said:

Really? I always have the tweeters on the outside and sound much better to my ears with wider soundstage emoji14.png

 

IMO, soundstage width is chiefly influenced by the distance apart of the tweeters - not the bass panels - so of course you get a wider soundstage when the ribbons are on the outside!

 

But the Maggie ribbons need space around them, to sound their best.  In my last room, my IIIas had ribbons on the inside - as there was only a 600mm gap between the edge of each panel and the wall.  In my current room, I have about 1.5m between the outside edge of the panels and each wall - so my ribbons are now on the outside.

 

Andy

 

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6 hours ago, DMax said:

Really? I always have the tweeters on the outside and sound much better to my ears with wider soundstage emoji14.png

I have previously had the Maggies with the tweeter out, in fact I ran the 1.7's like that.  When I did that with the 20.7's I certainly got a nice wide sound stage but it caused some frequency anomalies that I refer to at the start of this thread.  I am trying them with the tweeters in at the moment to try and get around some of those problems.  What the current setup provides is some bass reinforcement (as @andyrrefers to) and a very deep and wide sound stage.  The disadvantage as you note is a much narrower sweet spot.  Sitting in the outer seats shifts the center image fully left or right.  When I have friends over for a listening session they take it in turns to sit in the center seat.

 

Once I have found the optimal position with tweeters in I will swap them back to tweeters out and see if I can improve it any further.  If not I'll swap them back again.

Then hopefully that is where they will stay!  

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Going down the DEQX path requires money I don't have. I'm still recovering financially from purchasing the 20.7s!
Not sure what you ended up doing but have you thought about a less expensive but equally good option such as a DSPeaker Antimode 2 or a Minidso Dirac series. I have the former and run the whole signal through it, that is Maggies and subs, as if the subs were part of the Maggies.
This solved the timing issue beautifully and the subs are now perfectly integrated with no mudding if the sound, which I did have when I was running the DSPeaker on the subs only.
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