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trying to maximize the 20.7's, a journey....

45.23.36.40
Posted on December 2, 2018 at 22:29:44
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 for the last few months I have pushed ahead hard. My goal is to build the entire setup + room as far as my room will allow. Its a journey (an expensive one for me...) but i would like to share it and promote discussions from others on your journey with Maggie's and what has and has not worked for you.

I also apologize now for the long post but there are many moving pieces to this.

First the room size.
Initially the room was used for both HT and 2 channel. Since my kids have moved out i now converted it to a dedicated 2 channel setup. Its not a size some of you may feel will work, but it does actually work really well. And its now dedicated just for listening which has helped significantly. 23L x 11W x 8.5H. Speakers from front wall are 6 feet. 6" inches from side wall. I sit 17' 10" from front wall or about 11' back from speakers. the exact spot has taken a long time to reach but I am pleased now.

Equipement journey.
the 20.7's replaced Wilson Watt 7's which I never really liked. The WP highs were harsh and fatiguing, bass was good though. About 2 years ago at my very good local shop (HIFI Buys Atlanta) I heard the 3.7's and was blown away. I had never heard Magnepans before. The wall of sound was like nothing else i had experienced. I had audition many other box speakers but the planar sound spoke to me. Well I ordered a pair of 20.7's after much research. And Bigger has to be better right. Yes they are but they took a lot of effort to get the setup right - which is: tweeters on outside, speakers toed in some, and finally some tilt down toward my chair (i made my own adjustable stands, TIG welded). OEM bass was pretty good but i wanted the slam of the WP's. So for a while i tried a single DWM panel (it is actually 2 panel stereo in single enclosure) and it helped - some. After discussions with my shop, they suggested a "pair" of the new Vandersteen Sub 3's with built in EQ and with the optional HP5 cross over topology. And While i was at it i traded up from an AR Ref 5 to a Ref 6. Amps are Mcintosh MC601 monos. Cabling is fairly hi-end AudioQuest (Rocket wire and Colorado XLR). My source is Jriver for ripped/24bit and Tidal MQA through a PS Audio III Cullen modified DAC (for now), I have a Dcs Bartok on order. The wife is not happy and even i said I am done (as buyers remorse for all this crap set in). This has to be enough hi-end stuff surely....


Room correction
initially i had many 2" thick fibreglass absorption panels on side and rear walls (two 4' x 6' on rear wall and four 2' x 6' on side walls) , with just small ones on front wall coexisting with a 100" HT screen (which is now gone). I never really liked the sound though, so a few weeks ago removed all absorption panels just to see what would happen. Well it was an amazing transformation. Suddenly i have massive energy! the entire system woke up. But now there was slap echo. So I just completed building 12 skyline QRD diffusers for front wall. let me say i will never do that again, 1,800 F'en pieces. They are beyond monotonous to build, but they do look cool.

what does it sound like now and what is the last push:
transformed! the energy, imaging and sense of depth now is startling as compared to prior setup. The bass is absolutely kick ass. The Vandy subs are worth every $$. They seamlessly merge with the 20.7's which i surmise is due to the way the cross over topology is designed + each has EQ.

The last push: I have high expectations for the Dcs Bartok which should be here by the first of the year. I also know i need more diffusion. I am leary now of absorption but may still need some. I solved one bass mode issue with a bass trap. So my shop is coming again for an entire room map session and what i hope will result in a decent room correction plan.

If you got to this point, thank you.
Well folks what is there left to do, or is that a recursive question? Have i overlooked something? what have you done with your planars that your pleased with?

Cheers!

hughp3

 

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RE: trying to maximize the 20.7's, a journey...., posted on December 3, 2018 at 08:30:29
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 I would say you pretty much did all you should do, with the exception of trying to get the tweeters out position optimized. You probably want to take the tweeters out a bit further towards the side walls since the room is pretty narrow. I am assuming that you ended up with the tweeters about 24-30" off the sidewalls, leaving you with a rather sufficient but not optimal spread of 8 ft between the tweeters. With the help of some absorption panels on the nearby sidewalls just ahead of the tweeters you can probably move the speakers out more towards the sidewalls, leaving a smaller gap to the wall, thus increasing the spread and thus soundstage width.

Outside of convenience and being up to date, I am not sure that the DCS network player will improve performance, unless you are going for a pure native DSD chain, which the old PS Audio doesn't do. But do report what you get.

The project you did is very impressive and it would be very useful for us all to see some pics.

 

RE: trying to maximize the 20.7's, a journey...., posted on December 3, 2018 at 11:21:34
George6
Audiophile

Posts: 182
Joined: November 18, 2012
 Congratulations on putting in all the work needed to get the most from the 20.7! I have the 3.7i in a room of very similar proportions, much longer than wide.

Having positioned the listening chair in the spot where room modes are at a minimum, and then positioning the speakers where they seemed to sound best - tweeters out, very slightly towed in - I added acoustic damping (3" thick foam wedges) at the various points of reflection.

The points were determined following the method detailed by John Marks in one of his early Stereophile pieces, The Fifth Element #2:

https://www.stereophile.com/thefifthelement/358/index.html

At each of the points behind the speakers and on the side walls, I positioned a vertical line of 12" foam wedge squares, mainly at ear level. This treatment seemed to make the sound snap into focus, more than anything else I have tried.

The front wall (behind the speakers) has a combination of diffusion and absorption, positioned mainly by trial and error, but keeping the reflection points damped at ear level.

The speakers have sonically disappeared, with a soundstage covering the back wall (on some recordings even wider). Had some problem with sibilants seeming to come from one side or another, but more careful damping fixed that.

 

Agreed, posted on December 3, 2018 at 16:39:10
slapshot
Audiophile

Posts: 2248
Joined: January 9, 2006
 I posted several times about how Maggies are a long road. Once you purchase them, you often find yourself upgrading your components, and modifying your room--in my case, building a dedicated listening room.

I don't think many realize what a long road it can be to get the most out of a pair of Maggies. It's worth it, but it isn't for the faint of heart or the causal audiophile.

 

Update, posted on December 3, 2018 at 17:57:23
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014



Thanks to you 3 for the thoughtful replies. George6 I have 6 inches from the side wall. Best I can do. Satie i will certainly be testing acoustic treatments. I really am astounded how much I had over dampened the room. Will post a reply after the room has been mapped. On the Dcs, I was told the improvement will be as large as going from the Ref 5 to Ref 6 which was very noticeable. But it will pale compared to the subs. That was a home run.

I have pics uploaded. You will notice a hole in front wall. That will be filled this week with store bought QRD panels thank the goodness. Most of the pics are from the back of my chair.

Humm looks like I can only post 1 pic??
hughp3

 

RE: Update, posted on December 3, 2018 at 17:59:58
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014



Fixed pic 2

hughp3

 

consider Mye stands, posted on December 3, 2018 at 19:01:32
Green Lantern
Audiophile

Posts: 16952
Location: San Diego, Ca
Joined: November 12, 2002
Contributor
  Since: June 17, 2003
 and perhaps bi-amping a bit down the road.


Great looking setup! Do you have a source on the skyline diffusers?









 

RE: Agreed, posted on December 3, 2018 at 19:10:59
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Hello slapshot would you post a pic of your setup? Would love to see it.
hughp3

 

RE: consider Mye stands, posted on December 3, 2018 at 19:14:26
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 GreenL I am buying these also some hard wood 1D panels from amazon.

https://www.gikacoustics.com/product/gik-acoustics-gridfusor/
hughp3

 

RE: Agreed, posted on December 3, 2018 at 23:08:22
slapshot
Audiophile

Posts: 2248
Joined: January 9, 2006
 Last year, I simplified my system to just an integrated (Pass INT-250) and a Marantz CD player. Speakers are 3.6s. The arrangement is what is called the HKLimage setup; works wonders and might work for your setup as well--do a search for it here on the planar asylum when you're feeling adventurous!

And you can post multiple pictures if, after uploading one, you press "preview message"; then you can upload another...

Love the look of your listening room. Nicely done!







 

RE: consider Mye stands, posted on December 4, 2018 at 00:01:01
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 I thought you already have rigid stands you designed.

 

RE: Update, posted on December 4, 2018 at 00:07:52
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 Can't really do much more than that on the tweeters. Net of the absorption panel it will likely buy you only 8 more inches of spacing. I am surprised that you had not met with some tweeter issues so close to an untreated wall. Perhaps the toe in is helping in that regard. If you still have your old absorption panels, try them on the sidewall opposite the curtains (they act as absorbers). As things are with the one side absorbent and the other side reflective I would expect occasional image shift and surreal etherial images lacking in saturation. There should also be tonal effects, but I can't predict what they would be.

 

RE: Agreed, posted on December 4, 2018 at 04:39:35
Green Lantern
Audiophile

Posts: 16952
Location: San Diego, Ca
Joined: November 12, 2002
Contributor
  Since: June 17, 2003
 beautiful-









 

RE: Update, posted on December 4, 2018 at 07:28:50
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Nice setup Slapshot. I like it a lot. Very soothing. I would have tried some Pass amps if they were available on AG. I just sold some Krell FPB-350MCX monos. What a heater but sounded great. I stuck with the Macs after at least 15 swaps with the Krell's (oooh so heavy). Sonically very very little difference "I" could hear but I love the blue meters. Also, I had my tweeters on the inside too for a long time. Tried them outside while changing everything and they now sound good that way.

Satie - that's my adventure right now, room correction. The left bare wall actually started with three 6' x 4' x 2 inch absorption panels. The curtains are super heavy doubled thick sun blockers. I removed the left side wall panels and have the left speaker turned more flat to the rear wall. Boom instant energy, imaging and depth. In fact before I did the above, I thought my left speaker was damaged. Doing a L/R comparison in mono the left channel sounded as if a blanket was over it. Almost sent the speaker to Magnepan. But after the above its perfect. Now this is funny, I use the curtains to open a small window of glass, I use that to fine tune (ie move) the image to the center of the room. Its very strange but works. The whole acoustic thing is so hard figure out. Will see what my shop measures today + new deflection panels that I will install as they arrive.

Cheers

hughp3

 

RE: Absorption..., posted on December 4, 2018 at 11:36:06
BigguyinATL
Manufacturer

Posts: 3475
Joined: April 10, 2002
 Absorption is a Magneplanar's enemy. Where the initial reflections are the bane of traditional loudspeakers - like WATTS, the dipole minimizes side wall reflections and the line source minimizes the floor and ceiling reflections. Even the 20.x's are somewhat inefficient but you McIntoshes are more than able. Serious audio enthusiast envy here....

One thing you might want to try - it worked great on the 3.7's at Hi-Fi Buys "Middle room", is to try a tweeter in 40-45 degree toe-in.

I think a 7ft Wedge diffusor would have worked just as well for you on the back wall - but the QRD's likely look better. They do have the "expense" of their definite phase based attenuation at 1/4 wave distances - they will do well in an already diffuse room to solve the slap echo issue.

Bravo on your journey...


"The hardest thing of all is to find a black cat in a dark room, especially if there is no cat" - Confucius

 

RE: Absorption..., posted on December 4, 2018 at 19:52:02
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 thanks bigguyatl.

hifi buys mapped the room today. its evidently still on the dark side. guess the carpet and pad are the culprit but thats not going anywhere. room reponse overall was pretty good. thick HT curtains are going away for other coverings. going to try raising the speakers up on a slab, maybe use cheap stuff from homedepot for a test. will will try diffusion on rear wall especially behind my chair. i did add 2 base traps i already had to rear corners. not much i can tell but room sweep measurement said they helped. the feed back was i am close but the sound stage is too far behind the speakers. could be they are too far into the room? i guess moving them as a test is in order. also bass was a bit thick so will try setting the Q on the subs back a bit. the bass impact was excellent just a bit too bloomy.

this is all trial and error but i guess thats just part of the journey. will report back as i make changes.

Cheers
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on December 7, 2018 at 18:49:03
andyr
Manufacturer

Posts: 12548
Location: Melbourne
Joined: September 2, 2000
Yes to subs ... and yes to Mye stands, as GL suggested. Braced stands make a lot of difference to dynamics and sound staging.

Here's a pic of my own braced stands. (With my custom-made hardwood frames - which you needn't worry about, for your 20.7s. PG tells me it doesn't make the same improvement on 20.1s & 20.7s that it does for lesser models - he thinks it's to do with the double-sided magnet array making the 20.7 already stiff enough.)



Andy

 

RE: Absorption..., posted on December 7, 2018 at 19:41:42
timm
Audiophile

Posts: 780
Location: Ann Arbor Mi
Joined: January 15, 2008
 Very interested in your journey. I too have the 20.7 - but my room is 17x30x8. I have them about 9' off the front wall. Am wondering of the impact of diffusion on the front wall at that distance - if any improvements can be made.

My gut tells me your distance from the front wall is fine. What happens to the depth of stage when you remove the diffusers ? Wondering if the diffusion is creating the effect of having the stage behind the speakers?

 

RE: Absorption..., posted on December 7, 2018 at 21:14:01
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014



Update. My shop sent technicians out to do a room test. Attached is a RT60 graph that i was sent but they have not explained it yet. Anyone here know how to read one of these? Anyhow, the guys felt i was close but not there yet. Imaging is still too far behind the speakers, still a bit dark (to them) and bass was a bit bloomy although impact was good. the guys did feel the skyline diffusers helped a lot with the reverb ( if I can read this damn shart :) ).

At their suggestion, i move the speakers back toward the front wall. Initially i was 6 feet out, i settled on 5' 6" or so. 5' did not sound good. I do like this better. Imaging came forward a good bit. I am playing with Q on the bass. I seem to like 3 on a scale of 10.

I bought 3 of these diffusers to play with. Now i am buying 5 more.

https://www.amazon.com/BXI-Sound-Diffuser-Acoustic-Diffusion/dp/B0798SJ77F/ref=sr_1_1_sspa?ie=UTF8&qid=1544245516&sr=8-1-spons&keywords=acoustic+diffusers&psc=1

I tested filling the space between the skylines with 3 panels and also tested 2 of these panels behind my sitting position. Both tests brought even more energy and i liked the difference. Interesting, i tried the diffusers with slats horizontal and vertical. Horizontal sounded better for the upper row. Sound stage moved from near ceiling down a few feet which was good. Next tweak is to leave curtains on right side french doors open but i will add a 2' x 4' x 1/4" slab of lexan to hang over the fixed part of the french door adjacent to the speaker. I hope this adds the same reflection energy as the left side with drywall while killing the glass effect.

hughp3

 

RE: You raise some interesting points ..., posted on December 7, 2018 at 23:14:12
andyr
Manufacturer

Posts: 12548
Location: Melbourne
Joined: September 2, 2000
 "I too have the 20.7 - but my room is 17x30x8. I have them about 9' off the front wall."

Lucky man! :-)) AIUI, the more off the front wall ... the better! (Because the reflections from the front wall become more behind the front-of-panel sound - so the brain can separate them.)

"Am wondering of the impact of diffusion on the front wall at that distance - if any improvements can be made."

In my last house (27' x 17' with a 15' pitched-in-the-centre ceiling), I had my IIIa panels about 6' off the front wall. When I introduced some diffusion panels ("Room Tunes") just off the front wall, in line with the "reflected ray" from the ribbons (on the inside) to my ears ... I got a major increase in soundstage depth. :-))

But, yes - it was depth! IOW, the soundstage reached further back - to beyond the front wall of the room.

IME, a forward soundstage - which starts from the plane of the speakers and comes forwards ... is achieved by having tube amps driving the speakers. It is not an intrinsic artefact of the speaker itself.

Andy


 

Update, posted on December 16, 2018 at 15:12:17
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014



Update: finished installing amazon diffusers. 4 as a group on front and four in groups of two mounted on rear wall. Yes made another large difference. Improved imaging yet again, smoothed the energy from front wall.

Also my shop HIFI Buys loaned me AudioQuest Hurricane power cocrds to try. I poopoo'd these of course. It's wire, it's power wire. Hooked 2 up to the Mac monos, Well crap.... ok so maybe it's me. I sat the wife down who really did not want too. She said Alan had found another sucker. She and I both heard a level of grudge removed that is very real. Small but sweet. I really did not want my Amex near these but even she said go ahead lol. Interesting that the test on the AR Ref6 was kinda a no go. I think it's better but not for the money, the amps a no brainer. Who would have thought, it's wire....

Granite footers for speakers and subs next week. still waiting on the Dcs DAC to arrive then I am done.... maybe
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on December 16, 2018 at 22:33:59
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 What plan did you use for your skyline diffusors?

And more importantly, what Material?


Too much is never enough

 

RE: trying to maximize the 20.7's, a journey...., posted on December 17, 2018 at 08:34:06
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 pictureguy - I used this URL

http://www.mh-audio.nl/DiffusorCalculator2.asp

I made these out of pine 2x2. RT60 measurements from Cory at HiFI Buys said it worked. average delay is about 3MS. do not build these unless you like tedium.
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on December 17, 2018 at 10:58:00
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 You hit RIGHT on the main problem.

Plans for these are variable but usually call for 2"x2" material which '2x2' in wood is NOT.
That's 1 1/2" square.
So?
A 12 x 12 piece matrix will only be 18" on a side.

Excellent on 'ya for the measurements.

How much does each panel WEIGH? 20lb to 25lb, depending on hi/lo frequency limits and cell width would be my guess.

Would you be open to a better material choice?

My version thru the online calculator is 25.3mm X 25.3mm and cell height of 3"+ to about a foot.
Calculated limits are 500hz to 3400hz. That's of course not cast in stone, but I did choose the lower limit to be below the crossover frequency of my panels. (600hz).

Total weigh of my design with my choice of materials is about 2lb with additional weight for stand and thin Masonite 1/8" backing.......
A double panel model will certainly go no more than 10lb. As Installed.

I think for PANEL speakers, front-wall diffusion almost amounts to a 'must'. Especially for those like me who simply can't get the oft-discussed 5 feet minimum to that wall.
Too much is never enough

 

RE: trying to maximize the 20.7's, a journey...., posted on December 17, 2018 at 14:31:35
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Yeah I know about the 2" being 1.5" but it still works if you plug width in. What material did you use for light weight?
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on December 17, 2018 at 16:32:36
pictureguy
Audiophile

Posts: 22597
Location: SoCal
Joined: October 19, 2008
 EPP foam.
Available in sheets of either 1.5# or 1.9# per cubic foot.
Cutting can be a challenge, but CAN be done cleanly and very precicesly.


Too much is never enough

 

RE: trying to maximize the 20.7's, a journey...., posted on December 28, 2018 at 09:06:02
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Update:
Final speaker placement! I hope this is it.
Room length 21.5 f
Room width 11 f
Ceiling 8.25 f
as per pics, a lot of diffusion on front wall and some QRD panels on rear wall behind seat.

Speakers are 6.6 feet from front wall
Seating is 2 feet from back wall
tweeters inboard, tweeters toed in to my ears
speakers 7.5 inches from sidewall wall
2 degrees forward tilt


Thanks to Satie and all of you for all the threads about Limage setup. I tried 8 feet from FW but sounded like in a cave so kept moving back.

Now mids/highs are a bit over bright but very powerful and clear. I have not tried the resistors that came with the speakers since I know you guys have much better ones. Would you share which ones and how to get?

Thanks again...
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on December 28, 2018 at 21:14:36
timm
Audiophile

Posts: 780
Location: Ann Arbor Mi
Joined: January 15, 2008
 Wow. Ginormous change. Tweets in from out. I think a good move given your width. My guess this won't be the last of your experimentation. Your room doesn't seem overly bright and I have heard Mac gear and would never consider it bright. I see the drapes. What are they covering? How much muddling have you done w toe in? Just wondering if decreasing toe in a tad would help with brightness. Also what happens if you move the listening position up a bit to get yourself further away from the rear wall. Do you have any absorption to futz with on the back wall? Even a large blanket on back wall to see what that does? Just some thoughts Forward tilt?? Seems like this would essentially pull the bass panels back while making the tweet and mids more aggressive.

 

RE: trying to maximize the 20.7's, a journey...., posted on December 28, 2018 at 22:34:13
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Lol Tim you must have ESP. i bet while you were writing this up i was doing mostly what you suggested.

I removed toe a fair amount, still have some, i moved my seating forward about 6 inches and returned speakers to level. that helped a lot with brightness/harshness. the curtains cover french doors to outside. I have 2 groups of 2 qrd panels on rear wall (like front wall) but they are spaced apart . i could try absorption btwn them although the highs are better now. i tried the 1 ohm capacitors for the mids but i did not like it.

Lord this has been a lot of work. room sounds good but i need to go hear a reference system again. that would be my shop with Vandersteen 7 m2, pair of Sub 9, full Dcs stack, full D'Agostino gear + wire. a lot of money (about $300k). that system has an amazing noise/coloration floor, there is none and its a big difference. But mine is very dynamic, vocals such as Natalie Cole, are amazing. But i still hear some congestion which the Vandy system does not have. I am still awaiting the Dcs DAC.
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on December 29, 2018 at 07:48:05
timm
Audiophile

Posts: 780
Location: Ann Arbor Mi
Joined: January 15, 2008
 The Dcs replaces ... is that a ps audio dac iii it is replacing. That I think will be something special. Don't know if you noticed up the thread but I too have 20.7s in a less challenging room. I left a folding chair in the room as I was trying to get the seating position. I also put tape on floor to not revisit old positioning. I always tried to deal with one variable at a time. The question becomes what is the driver -1 distance from front wall. 2 seating position 3 toe in. 4 room treatment That was my order of what I thought was important Essentially get first one right and then move on to the next. Depending on the room confines - one of the above might trump the other in importance. I would dump the tilt personally - or put it completely last in the order above as I think it adds a variable that magnepan didn't really take into account design wise. Don't give up. In my opinion the scale you get from the 20.7 can't be touched. Looks like I saw a sub. Are you running it - and what frequencies is it handling

 

RE: trying to maximize the 20.7's, a journey...., posted on December 29, 2018 at 19:20:04
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 Looks like you ended up with a Limage setup. Curious to see if moving the curtains make a difference any longer.

Do tell us what the DCS does over the PS Audio original.

 

RE: trying to maximize the 20.7's, a journey...., posted on December 29, 2018 at 20:21:07
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Hey Tim, yes that's a PS Audio iii Cullen modified. Pretty good but I hope the Dcs will be a big difference. I have a pair of Vandersteen Sub 3 with high end HP7 crossovers installed before the Amps. The subs have sensitivity, 11 band equalizer and Q control. Bass is amazing now, not that the Maggie's were lacking, I just wanted concert level slam. The subs start to take over at 100Hz.

Just listened to my shops reference system. I am still a ways off, it's noise and or congestion. The Vandy system is so very clean. Still could be room reflections. I just can't tell. However the Maggie's have a big wall of music even in my small room with more life sized instruments than the Vandy. Will see how the Dcs DAC affects noise levels.


Satie yeah I think it is Limage or very close
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on December 30, 2018 at 18:43:39
George6
Audiophile

Posts: 182
Joined: November 18, 2012
 The big ceramic resistors Magnepan supplies can dull things down a lot.
I have had better sound with Mills, noninductive resistors. They are not too expensive so you could order several pairs with different ratings and experiment. Parts Express is one source.

Duelund carbon resistors, with silver coated leads, offer the 'purest' sound, but they are expensive and it is not always easy to tell in advance if they will fit into the Magnepan sockets. I have the 0R5 (.5 ohm)carbon/silver and they do fit. Inserted into the tweeter sockets, they will make a very subtle difference but not change the timbre.

Incidentally, the way you have lit your room is very effective -- it takes the eye past the large physical mass of the speakers through to the open space beyond. It may also have a positive psychoacoustic effect when listening.

 

RE: trying to maximize the 20.7's, a journey...., posted on December 30, 2018 at 22:03:48
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 The speaker panels may be a source of trouble in self noise. The driver's magnet boards tend to ring, and you can treat that in a few ways that require work underneath the socks or a simple but awkward mod that you can apply externally.

Look up Dawn Razor's Razoring mod, where the magnet board is covered by thin strips of CLD damping material leaving space for the holes. Very tedious with the two sides of a push pull panel. But you can get the effect without covering the entire surface, just 1/4 should do it.

The bow and arrow mod from Limage in HK is another one that damps the magnet boards. you can try it on the midrange or the bass section or both (that would look really ugly) you will probably want to do both the front and the back magnet boards and I would start with the midrange drivers as the target. Essentially you put a fishing line loop around the speaker horizontally and then pressure mount a chop stick or similar thin dowel between the magnet board and the fishing line. you can use a rubber spacer between the stick and the magnet board. Of course, you need to avoid the holes - or make sure the stick is thick enough not to go through one. You don't want to apply excess pressure as that will bend the magnet board inwards and reduce the membrane/magnet offset and cost you dynamics. You can insert your little finger between the speaker and the stick to gauge how much pressure is being applied.

Heavy bracing to stop sway is also helpful for the clarity you are probably missing relative to the big Vandy setup at higher volumes - if you are adventurous you can try mounting a dowel to the top of the speaker and hooking up the other end to the sidewall a few feet behind - I do this for my Tympani bass panels.

 

RE: "optional HP5 cross over topology" ...., posted on December 30, 2018 at 23:39:26
andyr
Manufacturer

Posts: 12548
Location: Melbourne
Joined: September 2, 2000
 Great story, Hugh.

I'm interested to know what the Vandy HP5 XO topology is? I use a 24dB L-R HP/LP XO with my subs - which works well ... but I can't imagine what anything more complicated would be?

And congrats for building 12x QRD diffusors for the front wall. I can well imagine it was "beyond monotonous to build"! :-))

In my experience, for good depth you need:
1. a good amp,
2. panels at least 5' away from the walls (6' 6" - I'm envious!), and
3. diffusion of the reflected 'sound rays' coming from the ribbons, off the front wall to your ears.

In my last house I had a wonderful listening room - about 27' long x 17' wide. So I was able to have my IIIas about 5' 6" off the front wall (1/5th of the room length). I got some depth to the sound stage but when I made up a pair of 'Room Tunes' (from instructions published here on Audio Asylum! :-)) ) - I found I got a substantial improvement in sound stage depth. I had my ribbons on the inside in that room - and the Room Tunes were placed just off the front wall, so that they interrupted the 'sound ray' from my ribbons, off the front wall to my ears.

As a result of that experiment, after I moved to my current house - where I am constrained to having the panels only 3' off the front wall - I built a diffusion panel ... which has given me some more depth.

Yes, I was thinking about a QRD panel - but, as this is not a man-cave - WAF came into it. So I built this!:







Which my wife is very happy with. :-))

Regards,
Andy

 

RE: trying to maximize the 20.7's, a journey...., posted on January 1, 2019 at 22:47:58
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Satie those are ambitious tweaks! I feel going into the patient may be a bit much for me. Interesting read about how a guy did it though. Brave.


hughp3

 

RE: "optional HP5 cross over topology" ...., posted on January 1, 2019 at 22:56:10
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Thanks for reply Andy.
I tried to find some technical specs on the Vandersteen XO, guess he is not sharing :) but here in the link.

https://www.vandersteen.com/categories/crossovers

Very cool looking setup.


hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on January 1, 2019 at 22:57:33
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Thanks George, I may try these if i cannot get the room tuned further.
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on January 1, 2019 at 23:18:05
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 Update.

I had a thought and since i have a fair amount of this stuff
https://www.auralex.com/product/studiofoam-pyramids/

I decided to fill in the gaps btwn the panels. also playing with placement of additional foam above QRD panels near ceiling corners. Well it works REALLY well. Amazing really. I have not finished as it is trial and error on how much. I over did it initially and it took all the life out of the mids/highs. So took it all off and started back piece meal. I will post pictures once i have the right mix. I think this is going to solve the muddy coloration and brightness. It is cool to add pieces and hear the difference immediately. I am about 85% there and yeah Its the room not the speakers as the improvement is immediate.



hughp3

 

RE: "optional HP5 cross over topology" ...., posted on January 1, 2019 at 23:27:02
andyr
Manufacturer

Posts: 12548
Location: Melbourne
Joined: September 2, 2000
 Thanks, Hugh - but, no, not very helpful. :-((

But it appears the Vandy device is rolling off your Maggies (to match the sub roll-on) - which IMO is exactly the right thing to do. (So many people who use subs don't do this - hence, all the reports of how hard subs are to integrate well with the 'main' speakers.)

Andy

 

RE: trying to maximize the 20.7's, a journey...., posted on January 2, 2019 at 12:36:00
George6
Audiophile

Posts: 182
Joined: November 18, 2012
 If you have the patience, you can play continuous white noise through the system while moving around the walls with a sound pressure level meter at ear level, noting with a light chalk mark where the spl is higher than average.
Then place the foam pyramids in a vertical line at those places you have marked.
It is difficult to get the right amount of damping at the right place, enough to make high, loud violins, with flute doubling for example, more tolerable, but your experimenting will pay off.

 

Another method, posted on January 2, 2019 at 13:18:29
George6
Audiophile

Posts: 182
Joined: November 18, 2012
 You can get a good idea of what problems need fixing by using a recording of a solo voice which emphasizes the sibilants and plosives. I use Tony Bennett's "The Silver Lining", or you could just download tracks 1 and 3 from iTunes (not MP3).
When he gets to the S in "Paris", it sounds like a small nest of snakes.

The voice should be dead centre in your soundstage when listening from your normal position, and the plosives and sibilants should not be at all detached from the voice. If that's the case, you are golden. If the S's etc. sound detached from his voice, one or more foam pyramid panels attached to the wall in the right place should bring things together. Lots of trial and error involved, unfortunately - maybe others have a simpler method.

 

RE: trying to maximize the 20.7's, a journey...., posted on January 3, 2019 at 20:47:15
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 George thanks for the link. Interesting read.

I think i will stop messing with things for a while. I tested 2 more QRD panels below the others. Did not like it, spread the vocals too much.

the sound now, to me, is a full spread, wall to wall with powerful, centered vocals. 95%+ of the music has the illusion of coming from behind the speakers. when i close my eyes the speakers are gone. Voices and instruments, if i point to them with eyes closed are behind the speakers (but not in a hole) and about 7 feet +- high. the front wall is gone. I do hope this is close to optimal as i have no other Maggie system to compare to , just the big Vandy setup.

The highest quality recording(s) i have found is the 24 bit/MQA of Steely Dan, album Gaucho. "Babylon Sisters" is spectacular.

Yeah gonna stop for a while and soak in the room a bit. will report back on the DAC whenever it gets here.

Thanks everyone for the great responses. This has been fun!


hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on January 4, 2019 at 05:48:33
InfinityApogee
Audiophile

Posts: 237
Location: Sk
Joined: February 14, 2014
 When making these difussers, can they be made with rough 2x2's, or do they have to be planed lumber?

 

RE: trying to maximize the 20.7's, a journey...., posted on January 4, 2019 at 17:48:16
George6
Audiophile

Posts: 182
Joined: November 18, 2012
 That is indeed optimal, from my experience.
Enjoy!

 

RE: trying to maximize the 20.7's, a journey...., posted on January 4, 2019 at 18:02:49
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014
 The calculator I used is here. You can put in column info.

http://www.mh-audio.nl/DiffusorCalculator.asp
hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on February 5, 2019 at 16:20:17
Hughp3
Audiophile

Posts: 30
Joined: February 4, 2014



Update 02/05/2019

Finally got the dCS Bartok. Replaces about 6 year old PS Audio DAC III Cullen modified.
How does it sound: Well I no longer need a .5 ohm attenuator or addition high frequency absorption. The harshness IS GONE! My benchmark (as mentioned earlier) was the big, mega dollar Vandersteen MK7.2 system which has an amazingly low noise floor. I think I am now THERE or darn close. The 20.7's + Vandersteen Sub Three's, even in this smallish room, are jaw dropping clear + have all the slam/impact of big boxes. really happy!

Final pics of room setup below.
And I contributed to the asylum for allowing me a place to show these.

Full system:
Magnepan 20.7
pair Vandersteen Sub 3 with HP7 cross overs
Mcintosh MC601 monos
Audio Reseach Ref 6 pre
dCS Bartok DAC
PC tower running Windows 7 (TIDAL MQA, JRiver)
JCAT FEMTO USB card
AudioQuest Hurricane and Dragon power cords
all rest of cabling high end AudioQuest
granite footers for speakers and subs



hughp3

 

RE: trying to maximize the 20.7's, a journey...., posted on February 7, 2019 at 09:35:36
Satie
Audiophile

Posts: 5426
Joined: July 6, 2002
 Great that the DCS Bartok fixed the digital top end. Good DSD/SACD generally solved it for me. But my way outdated Musical Fidelity DAC didn't have that much of a digital hardness.

When the time comes, you can deal with the 20.7's self noise from the magnet boards ringing and by draining the diaphragm from transverse waves. It occurred to me that instead of a bow and arrow mod, you can do a less awkward mod that someone had done here before, where they put in a board clamped to the frame with a screw pressing against a spring and damped by an O ring going through the board to contact one point on the magnet board. The alternative is to strip the speaker and put on damping strips - i.e. Razoring the magnet boards.

 

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