Thank you.The Sointuva is available in real wood or mdf options, currently at the same cost. Just fyi.
Thank you.The Sointuva is available in real wood or mdf options, currently at the same cost. Just fyi.
Understanding Bolted joints, torque retention, and pull out strength of inserts in various panel materials is absolutely and aerospace thing…When it comes to MDF or solid timber, these threaded insert nuts are the preferred mounts for anything that needs a specified fixing torque that is not affected by changes in board thickness due to gassing-off of manufacturing adhesives/binders and/or absorption of moisture resulting in dimensional changes. MDF is remarkably stable in lateral dimensions, but average to poor when it comes to thickness stability.
These inserts are suitable for 16 to 25mm MDF or timber from 20mm and up.
Insert nuts maintain a specific fixing force over the lifetime of the board, assuming correct installation and suitable torquing. ie, they don't come loose or expand the hole they have been jammed into...
View attachment 216064
The fact that March appears to be using well nuts, means he has little idea about timber or board construction techniques. Furniture construction is vastly different to aerospace.
Ha, well it's not being said that wood is the material of choice for space exploration!Like in the "spruce orbiter"?
Unless we’re talking about wooden satellitesWhen it comes to MDF or solid timber, these threaded insert nuts are the preferred mounts for anything that needs a specified fixing torque that is not affected by changes in board thickness due to gassing-off of manufacturing adhesives/binders and/or absorption of moisture resulting in dimensional changes. MDF is remarkably stable in lateral dimensions, but average to poor when it comes to thickness stability.
These inserts are suitable for 16 to 25mm MDF or timber from 20mm and up.
Insert nuts maintain a specific fixing force over the lifetime of the board, assuming correct installation and suitable torquing. ie, they don't come loose or expand the hole they have been jammed into...
View attachment 216064
The fact that March appears to be using well nuts, means he has little idea about timber or board construction techniques. Furniture construction is vastly different to aerospace.
Hickory Mars Rover (HMR2025), actuallyLike in the "spruce orbiter"?
Alan is gossiping amir and OP in his own forum now LOL.
When it comes to MDF or solid timber, these threaded insert nuts are the preferred mounts for anything that needs a specified fixing torque that is not affected by changes in board thickness due to gassing-off of manufacturing adhesives/binders and/or absorption of moisture resulting in dimensional changes. MDF is remarkably stable in lateral dimensions, but average to poor when it comes to thickness stability.
These inserts are suitable for 16 to 25mm MDF or timber from 20mm and up.
Insert nuts maintain a specific fixing force over the lifetime of the board, assuming correct installation and suitable torquing. ie, they don't come loose or expand the hole they have been jammed into...
View attachment 216064
The fact that March appears to be using well nuts, means he has little idea about timber or board construction techniques. Furniture construction is vastly different to aerospace.
Insert nuts are great, funnily enough though, of all the types available the version in your image are the worst kind for longevity in MDF. They separate the MDF into layers which can fail, at least that is my experience with them. The expensive EZ-LOK or cheap mass made types with a thread on the outside hold much better.The fact that March appears to be using well nuts, means he has little idea about timber or board construction techniques. Furniture construction is vastly different to aerospace.
Given the rounding on the corners in the design getting a high quality paint finish is really hard on most other materials. To find anyone in Australia to paint to that standard is expensive especially for small production runs.For $4K is it unreasonable to expect the use of real solid wood cabinet enclosure versus low cost MDF ?
Insert nuts are great, funnily enough though, of all the types available the version in your image are the worst kind for longevity in MDF. They separate the MDF into layers which can fail, at least that is my experience with them. The expensive EZ-LOK or cheap mass made types with a thread on the outside hold much better.
I'm not sure why anyone would mount those another way in a speaker but someone probably has. Fail was a bad word as I didn't mean that the insert would pull out.Insert nuts (like the flanged one pictured) can also be inserted from the rear of the board and that prevents the issue you mentioned as the board is then pulled together as the torque is increased.
Insert nuts come in a large variety of course. I spent a decade with the largest manufacturer of RTA furniture in the southern hemisphere at the time, where our MDF was arguably some of the best on the planet. All E0 from sustainable pine plantations in NZ. No poor quality Chinese board like everyone uses these days. Insert nuts, combined with superior board, all CNC routed holes and alloy thread connecting rods, meant board delaminating or separation just didn't happen.
Obviously, people with cordless drills and too much torque would cause troble, but mostly, you'd shear off connecting rods before pulling out an insert nut.
Insert nuts (like the flanged one pictured) can also be inserted from the rear of the board and that prevents the issue you mentioned as the board is then pulled together as the torque is increased.
At the end of the day, there has been more suitable mounts for large/heavy loudspeaker basket rims to timber cabinets for the best part of a century. Spiked t-nuts into the rear of the board, with a suitable compliant gasket under the driver rim is better for consistency, resistance to transport degradation and long term secuity of the mount itself.
Funny thing about the Purifi driver, the magnet assembly mass and total driver mass is not quoted in the spec sheet.
And we should not forget using spring washers together with the fixing bolts...
@Nuyes
Thanks for all the information and data!
Controversy aside, what is shown is that, even the smallest things (amount of filling, gap in the binding posts, uneven seal between waveguide and tweeter, loose cables, etc.) can -substantially- affect the performance of a speaker, even if its built with the very best parts (Purifi components and beryllium tweeter).
You would have seen plenty of those under your Yamaha NS-1000/1000M/1000X/2000 etc driver screws. Yamaha had lovely JIS #2 size head machine threads, captive flat washers and spring washers going into rear mounted insert threaded nuts.
I've sheared a few of those soft screws due to the fact some adhesives got into the threads by mistake in the factory and set like stone or the adhesives corroded the threads in situ after several decades! Normally, you can wick some acetone down threadlocked shafts to soften the glue residue. I think they were a type of torque-to-yield screw as they are considerably softer than most Japanese speaker mount machine screws. Plenty of people have changed the screws to hex SS as it looks better.
While there may be a driver resonance in Purifi driver, there is definitely a port resonance. It shows up in the modeling of the SPK5 in Bassbox Pro. See here...Driver resonance is evident in every test for speakers that use this Purifi driver including their very own SPK5 design. See ASR review below. The peak at around 380Hz is driver resonance not port resonance.
Purifi SPK5 Speaker Review (Prototype)
This is a review of the Purifi SPK5 reference speaker design for their PTT6.5W04-01A 6.5 Inch Woofer. It was built and sent to me by the company, Celuaris (member @sgoldwin). The unit was shipped from UK and did not travel well. Just about everything that could come loose, did come loose. I...www.audiosciencereview.com
Purifi has staked their reputation on low distortion in their products and I would probably avoid buying any speakers that use this Purifi driver until they resolve this flaw.
Distortion, The Sound That Dare Not Speak Its Name - PURIFI
Read any discussion about loudspeakers and you get the impression that distortion as a topic is eagerly avoided. If it is mentioned, it is done sotto voce, implicitly. For instance: “you can’t get good bass out of a small long-stroke driver. There’s no substitute for cone area when you want to...purifi-audio.com
While there may be a driver resonance in Purifi driver, there is definitely a port resonance. It shows up in the modeling of the SPK5 in Bassbox Pro. See here...
View attachment 216154
This seems a bit strong a call considering that this resonance is in one version of this driver and is not even clearly audible. Purifi's focus has been on IMD rather than HD. Not saying they should not try to improve but would avoid sacrificing the good on the altar of some notion of perfection (that does not exist in this domain).
With the utmost respect @Rick Sykora , if resonances or 'blips' on the impedance curve are picked up, why on earth aren't people zooming in with a linear sweep centralized around the problem frequency/ies? I'm genuinely asking.
Whenever I found a 'resonance' issue, I just switched to a linear sweep with a start/stop and step freq to highlight and locate the problem area. Amir's sweeps are log, log and more log. As the frequency goes up, those aberrations become less and less illuminating.
For $4K is it unreasonable to expect the use of real solid wood cabinet enclosure versus low cost MDF ? These are bookshelves right? Is that not reasonable in today’s market? At $2k per ? Honest question here.