Ron's Speaker, Turntable, Power and Room Treatment Upgrades

[Ron Resnick]

The dilemma is that once those cavities are closed up -- whether they are filled with absorptive material or left empty -- they are never being opened up again.

I could leave them empty, and if any absorption is needed up there, then put it on the face of the soffit.

 

[audioguy]

sorry if my tone was negative, not my intention. I did not intend to be critical.

this was just such a passionate subject and expensive lesson for me to learn.

No problem.

My "It's Always The Room" mantra is because many of the sonic issues that folks are trying to ameliorate with equipment changes/upgrades are first best addressed by passive room treatment - yet their rooms have NONE or close to it!!

When I purchased my first pair of Wilson speakers, I had this horrible 15 db bump at 65Hz - and the dealer who sold them to me said I could fix it if I would dump my Krell amps and get some other (don't recall) amp. We got into this huge argument (he was in my home) and I thought he was going to take a swing at me. He exited my home screaming all kinds of obscenities at me. THAT's when I started investigating room acoustics and am now more passionate about room treatment (ALL kinds) than any other aspect of audio.

 

[shakti]

I am currently reading the owner manuals of Gryphon Poseidon and Gryphon Pendragon speaker systems, as it is possible, that a Gryphon Poseidon will become my next speaker system.
(Pendragon and Poseidon have the same BassTowers)

Fleming Rasmussen of Gryphon has a clear understanding of room treatment, so he hates any absorbation and prefers Diffusors a lot. 2 decades ago , Gryphon was even selling Diffusors under the Gryphon brand.

Also Bass „tubes“ and „holes“ are seen critical, as the Gryphon specific Q-Damping of the bass towers interacts with the room.


My room currently is optimized for my former YG speakers, incl Absorbation and Bass corner tubes..

Integrating the Gryphon Poseidon will become a challenge, as I cannot forecast the interaction of my corner Bass tubes and Q- factor adjustment.

here you can read some of Gryphons advices for the room.

http://www.gryphon-audio.dk/media/1408/manual-pendragonv2.pdf

The Poseidon manual is slightly different, but has the same message.

 

[audioguy]

The dilemma is that once those cavities are closed up -- whether they are filled with absorptive material or left empty -- they are never being opened up again.

I could leave them empty, and if any absorption is needed up there, then put it on the face of the soffit.

Putting absorption on just the face will not not act as bass traps but rather just mid and high frequency absorbers. What are you planning on covering the soffits with? Fabric or drywall? If just drywall, then I HIGHLY recommend you fill them. Not as bass traps but they will act as huge resonating chambers if you do not. When I built the columns which hide my surround speakers, I built them out of MDF but they were empty. All I had to do was knock on them and you could hear the resonance. Quickly added insulation (lots of it) and problem went away. If you are covering them with cloth, then just don't cover them until you finish the room, get your system up and running and do some listening and measuring.

 

[Ron Resnick]

Putting absorption on just the face will not not act as bass traps but rather just mid and high frequency absorbers. What are you planning on covering the soffits with? Fabric or drywall? . . .

I agree. The only reason I would cover the soffit at all is to absorb mid and high frequencies, rather than have that sonic information bounce off the soffit and back somewhere else into the listening room. Otherwise I would not cover the soffit at all. If I cover them I would cover them only in the future, since it is just a matter of gluing on absorption panels.

The soffit actually used to have three large, zig-zagging cavities. The framing you see closed in those large cavities, and I am using the largest cavity in the middle as a storage space accessible from a guestroom upstairs. That storage space will be filled with boxes, so I am not concerned about it resonating.

. . . If just drywall, then I HIGHLY recommend you fill them. Not as bass traps but they will act as huge resonating chambers if you do not. When I built the columns which hide my surround speakers, I built them out of MDF but they were empty. All I had to do was knock on them and you could hear the resonance. Quickly added insulation (lots of it) and problem went away. . . .

This makes sense. So the only question is what material do I fill the cavities with before closing them up with drywall? Does that entombed material even matter sonically?

 

[audioguy]

This makes sense. So the only question is what material do I fill the cavities with before closing them up with drywall? Does that entombed material even matter sonically?

At the recommendation of GIK, I stuffed my soffits and side/rear columns with the fluffy (and itchy) pink stuff from Home Depot. Cheap and the fact that is ugly won't matter since it is covered !!

 

[Ron Resnick]

I am currently reading the owner manuals of Gryphon Poseidon and Gryphon Pendragon speaker systems, as it is possible, that a Gryphon Poseidon will become my next speaker system.
(Pendragon and Poseidon have the same BassTowers)

Fleming Rasmussen of Gryphon has a clear understanding of room treatment, so he hates any absorbation and prefers Diffusors a lot. 2 decades ago , Gryphon was even selling Diffusors under the Gryphon brand.

Also Bass „tubes“ and „holes“ are seen critical, as the Gryphon specific Q-Damping of the bass towers interacts with the room.


My room currently is optimized for my former YG speakers, incl Absorbation and Bass corner tubes..

Integrating the Gryphon Poseidon will become a challenge, as I cannot forecast the interaction of my corner Bass tubes and Q- factor adjustment.

here you can read some of Gryphons advices for the room.

http://www.gryphon-audio.dk/media/1408/manual-pendragonv2.pdf

The Poseidon manual is slightly different, but has the same message.

Thank you, shakti -- very thoughtful of you!

Yes, Flemming suggests the "Rule of Thirds."

I think it makes sense for me to start with the acoustic treatment I would apply if left to my own devices. Since Bonnie is engaged, I will use her products to accomplish the elements I know I want (carpet pad under carpet, three-sided curtain for the rear third of the room, Tube Traps in corners, absorption or diffusion at first reflection points).

I have in storage basic ASC 4' X 8' X 2" absorption panels. I will start by simply leaning this absorption product up against the walls at the first reflection points.

I would like to identify the right RPG diffusion product (Skyline?, Diffractal?) or RPG combination absorption/diffusion product (BAD Panel?) to test in comparison to the big ASC absorption panels.

 

[Ron Resnick]

At the recommendation of GIK, I stuffed my soffits and side/rear columns with the fluffy (and itchy) pink stuff from Home Depot. Cheap and the fact that is ugly won't matter since it is covered !!

Do you mean basic pink fiberglass attic insulation stuff in thick rolls?

 

[microstrip]

(...) I would like to identify the right RPG diffusion product (Skyline?) or RPG combination absorption/diffusion product (BAD Panel?) to test in comparison to the big ASC absorption panels.

As far as I know the best RPG diffusor is the diffractal - however it is really deep (9"). http://arqen.com/store/rpg-diffractal/ It is a compromise - if you want diffusion in the low middle you need depth. Some thinner panels have a cutoff around 600 Hz.

If you want detailed information you can find a master thesis just on (!) it here: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0ahUKEwj2p82s6v3WAhWLJhoKHdAwB5kQFgg2MAI&url=https%3A%2F%2Fnew.oberlin.edu%2Farts-and-sciences%2Fdepartments%2Fphysics%2Fdocuments%2Fprojects%2Fhonors%2FLandremanThesis.pdf&usg=AOvVaw0GFNECdYUm5pXcC4Af14Kk

 

[microstrip]

Do you mean basic pink fiberglass attic insulation stuff in thick rolls?

The more important parameter is fiberglass or rockwool density. The classical Owens Corning 703 in 3cft .

You can see absorption versus frequency of several well known types bellow .

Frequency……..100hz…..125hz….250hz….500hz…1000hz…2000hz …4000hz
Ecoustimac……..0.38….…0.39…….0 .63…..1.18……..1.11…….1.06……..1.09
703 (3pcf)……………........0.22 …….0.67…..0.98……..1.02……..0.98…….1.00
705 (6pcf)………..……......0.16……..0.71…..1.02……..1.01……..0.99……..0.99
1240 2" (4pcf)……….....…0.20……..0.61…..1.07……..1.06……..1.04……..1.07
RXL 40 2" (4pcf)……….....0.26……..0.68…..1.12……..1.10……..1.03……..1.04
OFI-64 2" 4 pcf .0.16.....0.22……..0.54…..1.19……..1.16……..1.11……..1.09

 

[Ron Resnick]

Thank you, microstrip.

I see the RPG Diffractals can be ordered in a custom eight foot length. I could just leave the RPG Diffractals free-standing against the side walls so I could experiment with the Diffractals versus the ASC absorption panels I have (which I could just lean against the walls).

The Diffractals can be ordered in natural walnut, which would match the seven foot deep natural walnut wood strip where the speakers and amplifiers will be located. I think the plan is coming together . . .

 

[Ron Resnick]

After processing comments here and comments on my Best Acoustic Products for First Reflection Points thread at http://www.whatsbestforum.com/showt...Acoustic-Products-for-First-Reflection-Points it is clear to me that it makes no sense to design and build into the listening room a prescription for acoustic treatments without the complete stereo system functioning in situ. As MikeL and others have admonished me these things cannot be figured out definitively a priori.

So, my revised plan is to work with Bonnie and her measurements in an empty room to make educated guesses to figure out the elements I know I want:

-- acoustic drapes in the rear third of the listening room covering the entire rear wall, and the opening to the equipment and back to the rear wall and the opening to the kitchen and back to the rear wall, in each case from the floor up to a height of nine feet from the floor to dampen reflections and provide absorption around the rear third of the room, and to delineate visually a rectangular space;

-- absorbers (my existing 4' X 8' absorptive wall panels) or diffusers (RPG Diffractals or Modfractals or wood SMT V-wings) at the first reflection points; and

-- towers of my existing ASC 16" round Tube Traps in the front corners of the room

This will leave the front two-thirds of the room reflective and untreated, except for wall-to-wall carpet (other than the walnut floor equipment strip) and the first reflection points which will require patient experimentation and A/B comparisons to figure out the correct methodology (absorption or diffusion) and the correct product (absorption panels or RPG Diffractals or Modfractals or wood SMT V-wings).

After these initial acoustic elements are in place in the room I will spend a long time fiddling with speaker positioning (maybe I will engage Jim Smith to make a recommendation on this, as PeterA suggests).

Only after these phases are completed does it make sense to have Bonnie come back, measure the room again, and make final acoustic treatment recommendations and decisions.

* * *

The beauty of my plan for curtains on the rear wall and on the rear third of each side wall is that they can be bunched to one side and decommissioned for audio use and retained solely for aesthetic use to delineate a rectangular room. I even could put RPG Modfractals or SMT wings in front of the curtains, retaining my small aesthetic objective about a rectangular looking room. The curtains just give me flexibility for the future and an aesthetic result I know I want, if nothing else.

 

[Ron Resnick]

MikeL writes:

Ron,

I just spent a few minutes on the Gryphon website studying the Pendragon details. I was trying to understand exactly the interface between the bass tower signal path and the main tower signal path. I was not able to determine where the bass towers receive their signal. it only describes a separate active crossover for each bass tower; but it is not disclosed where the signal for the bass towers is received.

do they take the signal from the main tower speaker terminal?

or do they take it from your preamp?

my question is; whether the character of the amps for the main passive towers with the Pendragon are part of the signal source for the bass towers?

with my Evolution Acoustics MM7's; the active bass towers take their signal from the speaker terminals of the main towers; which allows the character of whatever amplifier is used to be mimicked by the bass tower amps. which allows for a seamless character between the two towers in the bass. I've had a few tubed amplifiers in my system and never had a discontinuity in the bass related to different topographies.

if the Pendragon does get it's signal from the main tower speaker terminals, then the integration will be done for you already regardless of the amp you choose for the main towers.

we can all have an opinion or guess on how this might work. but I live with this approach, and it's awesome and the best bass integration I've yet heard anywhere.
​

Thank you very much, Mike, for looking into this!

The ribbon panels receive a full-range signal. If a pre-amplifier has two sets of outputs then the bass towers receive a full-range signal and the ribbon panels receive a full-range signal.

If a pre-amplifier does not have two sets of outputs then the bass towers receive a full range signal and there is a "loop" in the bass tower electronics which directs a full-range signal to XLR and RCA jacks. Those jacks are then used to feed a full-range signal to the amplifiers driving the ribbon panels.

To answer your question, the character of the amps for the main passive towers are not part of the signal source for the bass towers.

I like the EA and the REL method of tapping into the high level-speaker output of the amplifiers to feed a signal to subwoofers, so that that signal inherits the character of the amplifiers driving the main speakers. I think the Gryphon bass towers do not work this way.

So, that raises the question of how I get a full range signal to the bass towers and to the ribbon panels. The Aesthetix Io has XLR and RCA outputs, which I think are connected in parallel.

Can I use both the XLR and RCA outputs of the Io at the same time as though the Io had two pairs of outputs? I suspect not, because I think there would be some impedance issue with having two loads tapping the outputs at the same time.

So I could send one pair of interconnects from the Io to the bass towers, and use the loop built into the bass tower electronics to send the signal to the amplifiers of the ribbon panels, but then the length of the interconnect cables to the ribbon panels is longer than the length of the interconnect cables to the bass towers. Does this tiny time delay cause any issue?

Am I better off using a "Y" adapter at the ouput of the Io to simulate two pre-amp outputs? Or does this cause the same impedance issues as using both the XLR and the RCA outputs at the same time?

What would you suggest?

 

[Rodney Gold]

So I could send one pair of interconnects from the Io to the bass towers, and use the loop built into the bass tower electronics to send the signal to the amplifiers of the ribbon panels, but then the length of the interconnect cables to the ribbon panels (do you mean bass panels) is longer than the length of the interconnect cables to the ribbon panels. Does this tiny time delay cause any issue?

I dont see it as being a problem.
Ron what is the sensitivity of the pendragon passive panels... will you get enough volume with a lowish powered amp?
if you , for example are sitting 4 m from the speakers, you will be -12db down from that sensitivity figure at the listening position
(The sound level will decrease by 6 dB every time the source to the listener's distance is doubled.)

 

[trueblue]

The bass towers to the Pendragon are fed from a preamp output.

 

[bonzo75]

The bass towers to the Pendragon are fed from a preamp output.

So will the preamp driving them influence the sonics?

 

[trueblue]

That could depend on the preamps ablllity to drive 2 outputs or perhaps a long capacitive cable. ( some tube preamplifiers may not like it ) Given the low frequency area of operation from the towers, any sonic signature is quite unlikely.

 

[shakti]

As I have some experiance combining the Hypex driven subwoofermodels of my YG system with SET tubes for the satellites and as I am currently looking to theoretically merry Gryphon Poseidon mid/high's with the active Gryphon subwoofers, I like to share some thoughts.

Apart from any sound / performance results, the set up should work from the technical point of view, which is complex in it's own.

Let us have a look to the Aesthetix IO, which is a typical tube PreAmp, expecting high Impedance figures at the Amplifier side:


Aesthetix IO
Output impedance: 1K ohms SE, 600 ohms balanced
Recommended load: 10K ohms or greater (SE), 20K ohms or greater (Balanced)

( not using SET and XLR in parallel)



Looking to the Pendragon , it shows, that the XLR input would fit the bill with 40kohm:



Gryphon Pendragon
active crossover section included.

Input Impedans, balanced (20-20000Hz) 40KOhm
Input Impedans, single ended (20-20000Hz) 20KOhm

Gain +32dB


First logic would be, to combine the IO with a Gryphon amp and and the Pendragon on XLR. But unfortunately, the Gryphon Amps do have an input impedance between 10 kohm and 20 kohm which would give (using parallel cabling) a parallel input impedance of 8kohm or 13kohm, which is far below the IO can drive! So hard distortion would be the result.

The other aspect is the gain of the amps, the Pendragon has a gain of 32 db, the Gryphon amps do have 31dbm which is within the range you can adjust.


Let us have a look to the

NAT New Magma:

Input impedance 100 kohms
Gain +27.50 dB


Using at the IO the XLR output for the Pendragon bass towers (40 kohm) and the RCA output in parallel for the NAT New Magma, the IO would see a combined load of 29 kohm, which is within the Threshold.

But we would face a gain problem, as the NAT new Magma has only 27,5 db, which is 4,5db less than the bass tower.

But I do still assume, that this is within the adjustable range, as the most power amplifiers do have a gain of 26db, so the Pendragon Tower should cope with this.

If not, you can put the RCA cable to the Pendragon, which will give the basstower a arround 3db less powered signal and use the XLR cable for the NAT new Magma, which would make no difference , as the NAT is SET anyhow.


This is a pure technical view to the situation.

My current plan is similar, as I like to combine Gryphon Poseidon (if I can manage to get them) basstowers to Air Tight SET or NAT SE3 SET amps, having an Air Tight tube Preamp.

I heard Poseidon and Pendragon with Unison Reference tube Preamp and Unison Reference tube mono Amps, the results were great. On Poseidon, I had the comparison to Gryphon Mephisto Poweramp, I preferred the Unison mono amps.

 

[Bobvin]

Ron, I had a lot of questions re a soffit space a little like yours. If closed with sheetrock without some openings (which would turn the space into a resonator and require who-knows-what for calculations) I would fill the space between the studs with recycled blue-jeans cotton insulation. That stuff is dense and a great sound absorber. Behind sheetrock it isn't going to act like classic exposed absorber, but will reduce sound from bouncing around in the space. It was used in my room in joist bays (ceiling) and in the walls. In my opinion better than pink fiberglass, certainly provides much more sound transmission reduction. I had front corner spaces to treat but didn't fill the space just lined with the cotton insulation. Filling the entire void unnecessary.

I also have the Noiseout mass loaded vinyl between sheetrock and studs. It was spec'd for the ceiling, but I had so much I also put it on the sidewalls where we'd removed sheetrock. Overall I think the cotton insulation and mass loaded vinyl act to give the walls effectively more mass and prevent them from resonating.

Of course, as my thread described, we also had the custom diffusion/absorbtion panels covered with Guilford of Maine fabric — the fabric not totally dissimilar to what Mike L placed to cover hard reflective surfaces (if I understand his application correctly).

 

[Ron Resnick]

Bob, thank you for detailing this. Did you use two offset layers of screwed and glued sheet rock, or the NoiseOut covers a single layer of sheetrock?