Acoustics for Maggies ...

J. Royce Baron · « **on:** 31 Aug 2009, 10:00 pm »

I picked some Maggies 1.6 last year and just placed them in the same spot where the Vandersteen?s used to reside, all DIY acoustic panels were customized for the Vandys.

I'm now getting around to the Maggies and would like to customize some panels / absorption for the dipoles. Any rule of thumb that might be of benefit before I start?

bpape · « **Reply #1 on:** 31 Aug 2009, 11:39 pm »

Many people prefer diffusion behind the Maggies to expand the soundstage, kill the comb filtering, and do both without killing the back wave.

Bryan

J. Royce Baron · « **Reply #2 on:** 1 Sep 2009, 12:07 am »

At first rear reflections points?

On another note, would it be beneficial when building a ?super chunk? floor to ceiling to face it with kraft paper prior to cloth finish?

Thanks Bryan

bpape · « **Reply #3 on:** 1 Sep 2009, 02:43 am »

Chunk corner absorbers (faced or not depending on situation) can usually be of benefit.

The QRD diffusers would go directly behind the speakers and will scatter side to side and also in the time domain.

Bryan

Brown · « **Reply #4 on:** 2 Sep 2009, 01:04 pm »

Good advice Bryan [ as always] . Maggies love diffusion behind them as well as an absorbing rear wall. BTW put those tweeters on the outside and toe in about 3 inches or so. Depending on room size try about 7 feet apart for starters. Try using brass cones to lift them off the floor. A rear brace will also add to the performance. Check out Mapleshade Maggie stands for ideas.

Emil · « **Reply #5 on:** 2 Sep 2009, 02:06 pm »

Quote from: Brown on 2 Sep 2009, 01:04 pm

Good advice Bryan [ as always] . Maggies love diffusion behind them as well as an absorbing rear wall. BTW put those tweeters on the outside and toe in about 3 inches or so. Depending on room size try about 7 feet apart for starters. Try using brass cones to lift them off the floor. A rear brace will also add to the performance. Check out Mapleshade Maggie stands for ideas.

Here's a link to brace them for cheap. I've made them and they do work.

http://www.integracoustics.com/MUG/MUG/tweaks/green_lantern/

bdiament · « **Reply #6 on:** 4 Sep 2009, 04:18 pm »

I would not put diffusion near any speaker and particularly not a dipole.
Early reflections need to be absorbed. Scattering them with diffusors will defocus the soundstage and smear both the images upon that stage and the tonality of the instruments.

Diffusion can be a benefit with late reflections but in my view, is a liability with early ones. I would suggest comparing both and hearing this for yourself.

A bit more info can be found at
www.barrydiament.com/monitoring.htm

Just my perspective.

Best regards,
Barry
www.soundkeeperrecordings.com
www.barrydiamentaudio.com

J. Royce Baron · « **Reply #7 on:** 4 Sep 2009, 06:45 pm »

Barry ... looked forward to reading more info from your link unfortunately it's not working, can you fix it please?

bdiament · « **Reply #8 on:** 4 Sep 2009, 07:22 pm »

Quote from: bdiament on 4 Sep 2009, 04:18 pm

...A bit more info can be found at
www.barrydiament.com/monitoring.htm

Sorry for the typo.
That should be
www.barrydiamentaudio.com/monitoring.htm

And if you really want to hear your Maggies (or other speakers) really sing, try "floating" them:
www.barrydiamentaudio.com/vibration.htm

Best regards,
Barry
www.soundkeeperrecordings.com
www.barrydiamentaudio.com

Spirit · « **Reply #9 on:** 4 Sep 2009, 07:32 pm »

Barry:
Need a little clarification if you don't mind.
I own a pair of Apogee Ribbon speakers and reading their users forum, it appears that many Apogee owners use diffusors as apposed to absorbers BEHIND the speakers; on the front wall (as per what Bryan mentioned above).
When you stated in your post not to use diffusion near the spekers, did you also mean behind them as well? What kind of acoustic material do you use behind your Maggies?

Spirit · « **Reply #10 on:** 4 Sep 2009, 07:46 pm »

Barry:
How would you "float" a pair of Maggies (or Apogees in my case)? Do you mean to use an inner tube on the floor and sandwich a piec of plywood between the tube and the spikes?

bdiament · « **Reply #11 on:** 4 Sep 2009, 08:31 pm »

Hi Spirit,

Quote from: Spirit on 4 Sep 2009, 07:32 pm

Barry:
Need a little clarification if you don't mind.
I own a pair of Apogee Ribbon speakers and reading their users forum, it appears that many Apogee owners use diffusors as apposed to absorbers BEHIND the speakers; on the front wall (as per what Bryan mentioned above).
When you stated in your post not to use diffusion near the spekers, did you also mean behind them as well? What kind of acoustic material do you use behind your Maggies?

I would not use a diffusor facing a loudspeaker. This means directly behind speakers too, particularly a dipole, which will be firing right at the diffusor.

I believe many folks use diffusors behind their speakers because that is something they read on the web or in a "studio design" article in a magazine. Diffusion an early reflection, in effect scattering it will diffuse its effects, which in my view, should properly be removed from the listening equation by absorption.

In my own system and in rooms I design, I employ a modern day iteration of Harry Olsen's "functional sound absorbers". These are available in commercial form as ASC's wonderful Tube Traps and there are also a number of DIY (do it yourself) recipes on the web. The current style of functional sound absorber is cylindrical in shape. Half the cylinder's length is fully absorbent, while the other half is reflective in the treble. The shape of the reflective side does a great job at diffusing late reflection, when aimed away from the loudspeakers. That is to say, aiming the "dead", fully absorbent side toward the nearest speaker will help control early reflections, while the "live" side, facing away from the speaker, will diffuse late reflections.

And of course, the whole cylinder functions as a bass trap, lowering the "Q" or room modes and making for more dynamic bass response while preserving low level detail in the source by stopping the room from "filling in" the spaces between notes.

Do keep in mind that as with any other acoustic treatment, these must be used in sufficient numbers and they must be properly placed (and oriented - as mentioned above with regard to the live and dead sides).

Best regards,
Barry
www.soundkeeperrecordings.com
www.barrydiamentaudio.com

bdiament · « **Reply #12 on:** 4 Sep 2009, 08:39 pm »

Hi Spirit,

Quote from: Spirit on 4 Sep 2009, 07:46 pm

Barry:
How would you "float" a pair of Maggies (or Apogees in my case)? Do you mean to use an inner tube on the floor and sandwich a piec of plywood between the tube and the spikes?

While I use air bearings along with roller bearings for everything else, I do not find air bearings practical for loudspeakers. In my view, the risk of the speaker tilting and falling is one I don't want to take.

Instead, I use a trio of roller bearings under each speaker, as always with rollers, placed in the largest equilateral triangle that will fit under what they are supporting. (In my case, I use my own design, which I call Hip Joints.)

In order to give the balls in the rollers a hard, smooth surface to contact, I place a dead marble tile, smooth side down against the rollers, atop the roller bearings. With box type speakers, the speaker can then be placed atop the tile.

With speakers like my Maggies, which have a footprint that looks like an "H" and that is larger than the largest, dead tiles I've been able to find, I add a 1" plywood "platform" (sized to fit the Maggie's footprint) atop the tile, then place the speaker atop the platform.

WARNING: Small children and large pets should be kept well clear of floating speakers. Also, I make it a point to warn guests to stay clear as well.

In addition to the method outlined above, there is a commercial equivalent. Townshend makes a "Seismic Sink Speaker Stand" (or perhaps it has a different name now). I've heard many demos of this with the speakers on, then the speakers off the devices. To my ears, they accomplish the same thing floating with well designed roller bearings do, which is to free the speaker in ways I would not have imagined until I tried the idea. Every area of performance I know how to describe takes an immediate and obvious step upward in quality.

Best regards,
Barry
www.soundkeeperrecordings.com
www.barrydiamentaudio.com

Spirit · « **Reply #13 on:** 5 Sep 2009, 01:24 am »

Yikes, how this hobby can make you batty!!!
On one hand the mavens on the Apogee Users site insist that diffusers behind the dipoles is the way to go, and here, Barry, with his esteemed record and experience, believes that absorbtion is the only correct method.
Oh well!!

Spirit · « **Reply #14 on:** 5 Sep 2009, 02:11 am »

Now I feel really stupid!:
I didn't realize that when I was posting back and forth with "Barry" that he is in fact THE Barry Diament!!!
OMG - what an honour! Barry, forgive me. The CDs that you have mastered are legendary and if you tell me that diffusion should not be placed behind the Apogees that is gospel for me!!
For those who don't know who Barry is, read this thread at your leisure:
http://www.stevehoffman.tv/forums/showthread.php?t=79864&page=8

bdiament · « **Reply #15 on:** 5 Sep 2009, 11:31 am »

Hi Spirit,

Thank you for your kindness.

Regarding diffusion vs. absorption behind loudspeakers (or anything else), I can only report on my own experience. I suggest trying both if you have the opportunity to do so. That is the best way to find out the differences and how *you* feel about them.

Best regards,
Barry
www.soundkeeperrecordings.com
www.barrydiamentaudio.com

srlaudio · « **Reply #16 on:** 14 Sep 2009, 08:27 pm »

I for one, am more amicable to the use of diffusion behind the Maggies, even diffusion on the rear wall as well! Maybe even overhead and at the early reflection points. Am I crazy? Check out Blackbird Studios in Nashville Studio D. The Massenburg room. We recently took some of our products to the Nashville Guitar Amp Expo, where we exhibited in the Peavey room. They were demoing an acoustic guitar amplifier with an open back, and had requested that we "block off" the bedroom part of the room, which was behind the guitar amplifier. I placed a 4 ft tall 3 ft wide diffuser behind the guitar amp, and the effect was immediate, and positive. Everyone went "wow" that sounds better! So keep an open mind and check us out!
http://www.srlaudio.com/

Allen Rumbaugh

oneinthepipe · « **Reply #17 on:** 15 Sep 2009, 06:02 am »

How does your diffusion product compare, price-wise, with acoustic fiberglass panels? Also, what opportunities are there for DIY'ers? I have (22) 4'X8' acoustic panels in my room. How much would 176 square feet of your diffusers cost? No one here disagrees with diffusion. I would like some diffusers in my room. The problem is the cost. Just to replace the ( 8 ) panels on my ceiling with low/moderately-priced diffuser panels would cost $800.00 plus shipping. The four panels on my ceiling cost less than $50.00 each to make.

NekoAudio · « **Reply #18 on:** 15 Sep 2009, 06:14 am »

My personal preference is absorption behind my Magnepan 1.6 speakers. If I remove the absorption panels, the rear wave hits a column which is not exactly a diffusor but it does send the sound sideways into open areas instead of directly back to the listening position. I find the sound much more focused and accurate with the absorption panels. But I could easily see how someone might prefer diffusion because it creates a more interesting soundstage.

bpape · « **Reply #19 on:** 15 Sep 2009, 11:23 am »

It certainly is a preference.

On most speakers, I'd agree, no diffusion behind. On a full range dipole like a Maggie or any electrostat, fully 1/2 of the output of the speaker is from the rear wave and we don't want to lose that output. It's part of what gives a panel speaker it's unique sound. Also, absorbing behind a full range dipole can minimize the natural bass cancellations to the side of the speaker.

I do generally recommend absorption in between the speakers on the front wall.

Bryan