Topic: Rycote Single Lyres vs. Duo-Lyre Stiffness / Compliance

[aaronji]

I guess pretty much any equation with either mass or weight can be re-written in terms of the other, so, at least mathematically, they are interchangeable, if not in engineering terms. Here is an example I saw (for tractive force), where they provide the formula in terms of both weight and mass. Of course, nothing is so simple, as they note about the moment created by the engine during acceleration. I was kind of gratified to see "slugs" in there; I am not sure why that term still occupies some sliver of memory more than 30 years after my last physics class...

[Gutbucket]

I guess pretty much any equation with either mass or weight can be re-written in terms of the other, so, at least mathematically, they are interchangeable, if not in engineering terms.

 
..as long as the inertial axis in question is aligned with the vector of gravity. When cornering, the inertial forces acting on the mass of the vehicle are no longer aligned with the gravity vector.  Going up a hill the gravity vector is no longer normal to the contact patch between tire and road surface.  How well does that tractive force equation apply to a near vertical surface?  It then only works if we substitute force normal to the surface for weight.  We need to be very careful of the unstated simplifications in the mathmatical and engineering models, which sometimes become more apparent when the mathematical truths are applied to concrete engineering examples.  Same math though. 

Fun puzzlers, thanks.

[voltronic]

I just checked in on this thread expecting some questions about shock mounts. I wasn't prepared to learn science-y things!

[capnhook]

Better get the lyres that won't freeze or melt.  Crazy temps on the Moon.

 

[Gutbucket]

I'm double posting the message below from a mic bar question thread over in Ask The Tapers- https://taperssection.com/index.php?topic=196577.0 because it falls right in line with the discussion we've been having above, and were I'm headed myself-


The key to effective shock-mounting is achieving a reasonable match between the springiness/compliance of the suspension and the weight/mass of whatever is being suspended.  For very light microphones that are shock-mounted individually, one can add weight which is suspended along with the microphone to load the suspension so that the decoupling becomes is effective.  That helps in a pinch, but is unwieldy so it generally works better to shift to suspending the entire mic-bar along with a pair of lightweight mics.

With a large bar such as that nice looking t.bone StereoBar 1 Pro Voltronic linked [in the other thread], supporting micrphones of typical weight (not super small and lightweight), typical individual suspensions along the bar for each microphone will be the most straight forward and easiest approach.  If trying to suspend and shock mount a large and relatively heavy mic bar along with microphones rigidly attached to it, a larger and relatively more stiff suspension would need to be used.  This is the opposite problem of trying to individually shock-mount tiny lightweight microphones that don't have enough mass to effectively load the suspension on their own.

AEA used to make a big heavy-duty stand decoupler for use with large arrays like a Decca tree that they referred to as a "floater".  I searched for but can no longer find it nor a photo of one.  I'm in search of something like that myself for use between my multichannel microphone array contraption and its mounting stud that fits into the top of a mic-stand, clamp or support arm.  I don't need something as heavy duty as the big HD AEA Floater, so I'm thinking something like this: The Hook Studios Large Size MD-175-70 Mechanical Decoupler - https://thehookstudios.com/filters.html, or this Neumann decoupler -https://en-de.neumann.com/z-26-mt might work effectively while being sufficiently compact and streamlined aloft for me.  Otherwise I might build something myself using some Sorbathane samples I have on hand.  Of the 8 microphones I have in the array, 6 will benefit from improved decoupling, but 5 of those are tiny and weigh almost nothing, and I'd much rather achieve it using a single compliant element at the common support point. 

Rycote Lyres are great but not really the most appropriate geometry for something like this.  Annoyingly, none of the decouplers I've found including the one's linked above indicate a target weight range.

[Gutbucket]

The first two photos on the linked page show the two different sized decouplers.

The first shows the bigger one, Large Size MD-175-70 Mechanical Decoupler (diameter: 1.75") supporting an AKG C12.
The second shows the smaller one, Standard Size MD-150-70 Mechanical Decoupler (diameter: 1.50"), supporting an AKG 460 (held via another shockmount clip)

In both cases the Spin Grip mount (I've never seen one before) is on the support side, not the suspended side the decoupler.

I'll probably order the larger one, its probably about right and not too pricey.  I'll weigh my rig to see how close it is to a C12, and contact them to inquire about weight ranges.  Guessing the weight is pretty close, although I will be supporting long leverage arms extending outward.  I'll need to use 3/8" adapters on either side of it, maybe turning down and re-threading the stud side on the lathe in the shop.  If I end up making my own, it will likely be of similar construction using a larger diameter Sorbathane "puck".  The Sorbathane pieces I have are quite compliant and I think I'll need a somewhat larger plate on either side to limit sag. May incorporate a locking ball mount between the decoupler and mounting stud for tilt and swivel.. or maybe just a simple locking hinge, which should be sufficient.

[voltronic]

The first two photos show the two different sized decouplers.

The first shows the bigger one, Large Size MD-175-70 Mechanical Decoupler (diameter: 1.75") supporting an AKG C12.
The second shows the smaller one, Standard Size MD-150-70 Mechanical Decoupler (diameter: 1.50"), supporting an AKG 460 (held via another shockmount clip)

In both cases the Spin Grip mount (I've never seen one before) is on the support side, not the suspended side the decoupler.

I'll probably order the larger one, its probably about right and not too pricey.  I'll weigh my rig to see how close it is to a C12, and contact them to inquire about weight ranges.  Guessing the weight is pretty close, although I will be supporting long leverage arms extending outward.  I'll need to use 3/8" adapters on either side of it, maybe turning down and re-threading the stud side on the lathe in the shop.  If I end up making my own, it will likely be of similar construction using a larger diameter Sorbathane "puck".  The Sorbathane pieces I have are quite compliant and I think I'll need a somewhat larger plate on either side to limit sag. May incorporate a locking ball mount between the decoupler and mounting stud for tilt and swivel.. or maybe just a simple locking hinge, which should be sufficient.

Well, that was piss poor reading comprehension on my part! I completely missed the part about two different sizes. I'm deleting my earlier reply for being completely off base.

For either this commercial version or what you are envisioning for your DIY version, are the threaded fittings with their flanges simply epoxied to the Sorbothane?

[Gutbucket]

I assume the flanges are flat surfaced and adhered to the Sorbothane using some kind of adhesive effective enough to resist edge pealing away from the flanges when a side-load is applied.

Making the flanges of sufficient diameter to counter excessive "floppiness", in combination with sufficient thickness to effectively isolate, while keeping the thing relatively compact will be key if I end up building something. We have some funky industrial two part fusion adhesive we used to join rubber pads to stainless or aluminum which may work.  We also just had a sample of super sticky backing tape adhesive stuff dropped off which might work.  Its the adhesive with a release paper backing found on the backside of the lighytweight foam footing surface material originally used on surfboards, then jet-skis and wave runners, and now as decking surface pads on small fishing skiffs and ski boats.  We had some custom panels of that foam decking cut for a job and after I applied one of them I realized how tenacious its adhesion is.

I've considered worst case failure modes if the decoupler were to disassemble itself while aloft and I was recording. In that case the microphone cable bundle in its techflex sheath is secured both above and below the coupler and would keep the assembly from completely falling to the floor from atop the stand.  Obviously I'll test it extensively first and check for wear to prevent that, and could design in some sort of restraint which allows free movement but not complete disassembly, but I don't expect I'll need that complication.  Hopefully the off the shelf Hook Studios decoupler works as is or with slight modification.  Stay tuned.

[DSatz]

I've had Neumann Z 26 decouplers for many years and have used them in the occasional, odd situation. With their stiffness, to me they seem designed for heavy microphones. I often stack a pair of them for use with smaller, lighter microphones.

I don't feel as if they do me much good, frankly--but in some situations it's a choice between some good and none.

--best regards

[Gutbucket]

Thanks for that input.  Is the compliant part made of rubber or some sort of squishy urethane (which is what Sorbathane is)?  I included the Neumann Z 26 because it was the only other one that came up in my web-search, even though it didn't seem ideal for this application.  It looks rather stiff to me in the photo, but I have to question my own perception on that - what does stiff look like in still photo such a part?  I guess its the length x width ratio of the rubber part.  If it were compliant enough along its primary axis, it would flop over easily under a bending load.  It actually resembles the small motor mounts we use at work on electric motor hydraulic power units, which are relatively hard rubber and not nearly complaint enough for an application such as this.

[phil_er_up]

Could use some help:

Here is the Shapeway DIN-NOS-402X v1 mount I have and would like to use it with a Rycote shockmount.
https://www.shapeways.com/product/SZGZH5YJD/din-nos-402x-v1

Looked through this thread and not sure which one I would need. Already have the Rycote softer ones just for the DPA402X.
Can someone recommend which Rycote shockmount I would need to purchase to support that weight and 4 mics and being a vertical mount?

Thanks in advance.

-p

[scottsch3]

Patrick - The InVision INV-HG mkIII should work well with that setup. I could almost get away with using that shock mount with the same Shapeways NOS/DIN mount for the MMP-C bodies which weigh twice as much as the MMP-ERs but I ended up buying the Duo-Lyre, 72 (19/34) Modular Lyre upgrade for it to accommodate the extra weight. I can let you try out the standard INV-HG mkIII if you want to make sure it works before you buy one - just let me know.

[jbell]

The single Rycote Lyre will work fine with the DPA's!  I also linked the Duo Lyre and SRS base.

https://www.bhphotovideo.com/c/product/809861-REG/Rycote_042255_042255_Pair_of_Softer.html/?ap=y&ap=y&smp=y&smp=y&lsft=BI%3A514&gclid=EAIaIQobChMIqNWE-ba08wIVy-2zCh0B2QugEAQYASABEgJpxPD_BwE

Duo Lyre
https://www.adorama.com/ry040138.html?gclid=EAIaIQobChMIiIHkyre08wIVFa_ICh3iTwrYEAQYASABEgIDC_D_BwE&gclid=EAIaIQobChMIiIHkyre08wIVFa_ICh3iTwrYEAQYASABEgIDC_D_BwE&utm_source=adl-gbase-p

SRS base

https://www.ebay.com/itm/133298041528?hash=item1f092eb2b8:g:7XMAAOSwy-le44sI

[voltronic]

Patrick - The InVision INV-HG mkIII should work well with that setup. I could almost get away with using that shock mount with the same Shapeways NOS/DIN mount for the MMP-C bodies which weigh twice as much as the MMP-ERs but I ended up buying the Duo-Lyre, 72 (19/34) Modular Lyre upgrade for it to accommodate the extra weight. I can let you try out the standard INV-HG mkIII if you want to make sure it works before you buy one - just let me know.

I agree that either the standard INV-HG mkIII (with the 68-shore Duo-Lyre) or with the 72-shore Duo-Lyre will be what you need for this quad-DPA setup. A pair of individual Lyres isn't going to cut it.

If it turns out the standard 68-shore Duo-Lyre works, you can save yourself money by purchasing this mount, which is the same performance as the 68-shore Duo-Lyre in a non-modular config:
https://www.bhphotovideo.com/c/product/1544187-REG/rycote_41138_invision_on_camera_universal_shotgun.html

Also, as much as I am a fan of the SRS Base jbell linked, it is not going to work for that Shapeways mount, because you need the pitch adjustment found on standard Rycote bases.

[phil_er_up]

Thanks Scott, Jbell and Volt for your suggestions. Will have to ponder this more...