Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ.

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Tweakers' Asylum ]

---

[ Alert Moderator ]

---

Rick's Brass Screw Tweak

Posted by Dryginger2 (A) on June 4, 2015 at 16:59:14

Rick's Brass Screw Tweak

Thanks to ipdtt posting this link here for Rick Schultz's tweak https://www.youtube.com/watch?v=TeG-ARcM2zw , I implemented it last month. Using a 1/4" drill-bit and screwdriver, it took several hours of cautious work to substitute the 32 x M4 brass inserts and machine screws (costing $40 from McMaster-Carr) for the installed #8 brass 1.25" brass wood screws. It should come as no surprise that the much tighter and permanent MDF anchoring achieved by the threaded inserts largely eliminates distorting micro-vibrations between tapering wood screws, speaker boxes and cabinets to allow more detailed definition of even small musical notes and a more natural musical tone to emerge.

Rick warns that this tweak is only for those who have confidence in their woodworking capability since there is the potential risk of doing irreparable harm to the speakers. Perhaps it would help if I more closely identified where, on the basis of my recent experience, such risk is precisely located, so that those considering it may more closely assess their potential exposure in advance before deciding whether to proceed.

Let me start by saying that, if the format of my Vienna Acoustic tweeters shown in the attached shot is in any way typical, then the worst of the risk is in the tweeters and they should be done last when familiarity with drilling holes and the technique for installing brass inserts in the enlarged holes has first been developed on the woofers and mid-range. As you can see, the two right-hand tweeter holes are close to the edge of the aperture so that drilling a less-than-level-and-straight hole would almost certainly remove some of the separating wood edge. Installing a misaligned threaded brass would likely remove more wood as would possibly a later attempt to correct the misalignment. The risk-averse will be wise to avoid such a potential nightmare and take their speakers to a professional wood-worker in order to have this tweak implemented.

For those with reasonably steady hands and nerve, it's not impossible to slowly drill level-and-straight to a depth of 12mm (marked by tape or paint on the drill-bit). Placed 66% of my attention of keeping the drill-bubble dead central and 33% on the drill-bit marker as the MDF cabinet depth was 20mm in very slowly drilling the first woofer hole. There may have been a slightly deeper than 12mm hole (insert is 9mm to which I added 3mm for surface-burying as I ordered 16mm long brass machine screws) but this priority led to the orientation of the all 32 holes being correct after starting the drill-bit in the existing hole.

My nerves were tested when two of the first six basket machine screws did not quite align with their threaded inserts. Using a flashlight to check the direction and degree of misalignment before dismounting the basket and unscrewing those inserts, I took a wood screw and filed away a tiny amount of the obstructing MDF to facilitate the slight re-orientation required and re-installed them as tight as the others. The cause of the threaded insert/ basket hole misalignment was no mystery since it was difficult to screw with force threaded inserts straight-and-level under pressure into 1/4" holes that were sufficiently large to take their threads but not their level front-ends. The consequence was that they had an invisible tendency to vere slightly off the alignment axis despite my best endeavors. The solution became obvious; to first turn the head of 1/4" screwdriver in the screw hole 180 degrees in order to create a large-and-level entry point for the head of the brass insert before starting to screw the thread in. I subsequently never had any further difficulty screwing their threads in straight-and-level to achieve machine screw/ brass insert alignment.

Over-tightening the basket machine screws caused the speakers to be over-dampened and the music to sound like brittle hell but releasing the tension about an eighth of a turn produced the above improvements. Don't yet have the Precision Instrument Fully-Releasing Driver shown beneath to achieve the all-round 15 inch-pounds nor have I yet implemented Rick's recommendation for brass machine screws with a torque-drive reading specification. Given my experience, would advise taking advantage of Uncle Stu's risk-free channel-separator tweak first before even considering Rick's Brass Screw Tweak, partly due to the exceptional level of improvement with the former and partly to the risk exposure with the latter. Am personally delighted that I did both and in that order. Hope this helps.

DG

Item 96686A264 Metric Brass Flat Head Slotted Machine Screw M4 Size, 16MM Length, 0.7MM Pitch, 2 x Packs of 25 @ $14.98*
www.mcmaster.com/#machine-screws/=xdswr6 *note: prices vary with Pan Head/ Flat Head/ Phillips/Slotted
Item 95631A075 Metric Brass Tapping Insert for Wood M4 Internal Thread, 0.7mm Pitch, 9.53mm Length 4 x Packs of 10 @ $4.09
http://www.mcmaster.com/#brass-inserts/=xetlge
Precision Instruments (PREMD1F35H) 1/4" Sq. Dr. 5-35 lb. in. Fully-Releasing Driver @ $143.39 www.amazon.com/gp/product/B007QV1B4U/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A8Y9N35ANEOVV

Edits: 06/04/15 06/04/15 06/04/15 06/04/15 06/04/15 06/04/15 06/04/15 06/04/15 06/04/15

This post is made possible by the generous support of people like you and our sponsors:

Signature Sound

[ Signature Sound Lounge ]

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---