Has anyone seen the short video from Virtual Dynamics showing the owner replacing all his speaker screws with all brass screws? I was wondering if you could hear an improvement. It's a cheap tweak, so I thought I might go to Home Depot and try out a set. What can I lose?
Exactly..You got it going thats great. The whole idea is not to store excess energy whether it be a musical instrument a speaker cabinet or an electronic device. You want to lessen the time signature much as you would in a capacitor. You want the note to bloom on its own and disperse before the next note enters and blurs the previous. The bigger and more inert the more important it is to couple this mass to the higher mass below . There are drivers that have bronze baskets. I have not listened to any. Tom
Tom, yes I've thought about aspect that since I posted originally. I'm still amazed that screws alone could have a big impact on sound in a typical speaker mounting situation. The low mechanical impedance of brass is still constrained by the gasket material around a speaker basket, the vibratory characteristics of the speaker basket, and the vibration damping capacities in the many materials used in a speaker. I wonder how much relevance can be drawn from the musical instrument analogy. An instrument is designed to vibrate and radiate sound, no surprise increasing mechanical coupling to the floor enhances sound. A speaker, to greater or lesser degree depending on manufacturing budget and skill of designer, is supposed to be as inert as possible. Of course we know from looking at all of the accelerometer graphs in Stereophile that all cabinets vibrate to greater or lesser degree, so the coupling angle you mention may well be a factor. This all got me wondering what effect might be had from using brass or bronze as speaker basket material instead of the usual suspects.
Whatever else you do, don't buy the brass screws from Lowe's or Home Depot. During some repair work to back door, while gently easing in--i.e. *not* high torque--a longish brass screw bought from Lowe's it just sheared off.
Experiencing the audible advantages that brass has added to floor mounted musical instruments, I believe that the active harmonic structurer of brass fasteners in relation to the mass of a speaker cabinet would be a benefit. The extraneous active vibration of the driver would be drawn away, to and thru, by the low impedance reactive nature of the brass material and grounded to the much higher mass of the speaker cabinet. It would then be up to the owner to properly terminate or ground the speaker to the flooring surface a much greater mass again. Tom
I thought I was an audiophile nut, but I just can't bring myself to try this one. At 52, I must have reached the end of that perfect sound quest.....until something else comes around.....
Photon You are right about those fasteners in use with mdf. I dipped my brass screws in Cascade Audio paste. The paste product is like concrete when it drys and it is drawn into the pores of the wood or mdf. When my Dunlavys were in use I sealed all reachable internal surfaces with Cascade. Major hours and pain endured. When I was finished with this part of the project, the stage was wall to wall or 21 feet wide. New brass fasteners ideally should have a deeper cut thread to reach further into the wood surface. Brass around the tweeter dome and all crossover standoffs and fasteners should be brass..There is a sonic difference..certainly cleaner more articulate and less confused..Tom
We've got too much time on our hands! Brass mounting screws vs. steel, don't you wonder how much affect this can really have when their mass is so insignificant relative to their proximity or lack thereof to the voice coils magnetic field? I wish my brain could retrieve this tidbit in totality from memory, but I remember a speaker manufacturer speaking about the issue of screws, speaker mounting, and mdf. It may have been the owner of Magico in a recent Stereophile or Absolute Sound issue. Anyway... he talked about the dangers and deficiencies of using mdf as cabinet material because of it's propensity for losing ability to lock screw threads with the stresses of constant vibration and the passage of time. No doubt part of his spiel is self serving, but as someone with a bit of experience fabricating sculpture and furniture, I can attest to the potential for weakened threads if you back out and replace screws in mdf. Personally, I think the dangers likely outweigh the potential rewards. At the very least, I'd think about putting the speaker on it's back side after removing the screws and reinforcing the thread walls with tiny amounts of thin superglue applied with a needle applicator.
Most tweeters use metric size to hold the domes in place. Vifa, Seas, Scanspeak, Peerless all use metric. Brass the metal of music, on a t-shirt coming your way soon. Tom
Ouch! They must not have been packed very well. Are you still contemplating trying out a pair in the future? I saw a used pair for sale recently( maybe that's the same guy that sold to you) as it was marked for sale in the heading but the ad remained there for a while.
Grant, It depends if your screws are US or metric. You'll need to take one of each type of screw you intend to replace to a hardware store or Home Depot,Lowe's and measure for thread type, length, pitch,etc. so that you exchange out for the same in brass. I actually had to buy two types, one wood for the external tweeters and woofers and metric machine type for the tweeter internal screws. I can send you some of mine, but if they're not the same size, you could strip out or damage your speakers. You could always contact the Silverline tech and ask them what the screw measurements are for your speakers. That would save you the time of taking them out and to a store to measure them. If the size is the same as mine, I'll send you some. We'll e-mail privately at that point. I had a very positive transaction with McMaster-Carr( my first). I got the screws from two different warehouses within 3 days from ordering. If you look at the McMaster site, you'll see that they have a variety of heads to choose from. My external driver screws are panheads( factory screws are allen type, but I chose philips. Slot head might also be available. My internal tweeter screw heads are flat heads, philips, that are for presunk machine thread holes so that the heads are flat with the tweeter plates.
I searched all my local hardware stores as well as the more popular "nuts and bolts" boutiques and let me tell you folks, brass screws, particularly brass machine screws in small metric sizes( ones needed for my tweeters) were very difficult to find. Most don't stock specilty brass screws because brass screws were almost all replaced by stainless steel screws a while back for most contractors. Although stainless steel is non-magnetic and holds up better to the environmental forces), it still causes "Hysteresis"( did I spell that right?) when in close proximity to magnets. Brass is still the screw of choice for things audio related. Most of the sales people told me that brass screws these days is mainly used for decorative purposes. After a lengthy google search I found a good supplier where I could order directly from their website, Mcmaster-Carr. here is a link for those interested in pursueing special-sized all brass screws for their speaker drivers:
http://www.mcmaster.com/
Just type in "brass screws" in the search window on the left and it will take you to a list to choose from. Prices are very reasonable. I got a box of 50( minimum order. I only needed 16 total, so I have plenty extra) of a metric machine brass screw of M4.7 x 6mm for $9.00. I just replaced the steel screws on the inside of my speaker tweeters and the sound is much more natural and open. I haven't yet experimented with torque, but just changing to brass made a nice improvement. I also found a very nice calibrated Proto torque screwdriver, made by Stanley, (retails for $200.00) for $40.00 on Ebay.
To place a Sistrum platform under a speaker like yours would require at least two people. The first step is to predetermine where the speaker sounds best and to mark that area. If the floor is carpeted I stand on the platform so the points penetrate the carpet and pad. With the help of a friend or two I would then place the speaker on the upper set of points. I would have on hand 3 APCD discs for each speaker to rest on. These offer surface protection but also in this case allow you to slide the speaker front to rear left to right and adjust for toe in. The discs before they settle in allow for a smooth surface for the speaker to be tweaked geometrically. This is important to match all the angles of say the left speaker to the right speaker. Some speakers sound better, different with or without the APCD discs engaged. They can be removed after the angles are determined. One at a time by tilting the corner of the speaker and allowing for the disc to fall away.
The platforms vary in their reactance. All 3 will improve your speakers. The speakers will sound better on the platforms from the get go. They will need to settle in as will your speakers. Vibrational drain will develop a pattern over time usually complete after 96 hours. Its very informative to hear this steady progressive improvement. Enjoy and if you have any further questions I will be happy to answer as I can Tom
Take a screwdriver that has a magnetic tip along for the ride. If its sticks or it has a draw its ferrous. Go for the brass not the stainless. Brass is the metal of music.Tom
Its the brass material 95% and the torque the balance..thats the measure of it all. The torque measurement device has much to do with adjusting for the shear strength of the brass material. Versus that of the inferior sound and greater shear strength of the steel usually supplied and installed by the factory. Brass is the metal of music. Tom
I could not find brass screws which were a close match. I did tighten the screws on my TAD 805SD a couple inlbs. They still sound great, especially for the price, but nothing startling to report here either.
I kept waiting for you to say the wrench lost grip of the hex driver, slipped and went through a woofer. A real relief to read you lost only time and not parts.
This is the same outcome as my test. I admit I did not even look for brass screws, although that is probably the valuable part of the tweak.
Hi Tom, One guy used toothpaste on his Jordan's as a reversible experiment. Someone else used Post-It's!
[url=http://www.diyaudio.com/forums/search.php?s=&action=showresults&searchid=1163808913&sortby=lastpost&sortorder=descending]diy audio[/url]also has foam triangles you stick on the back of the driver. Called Mamboni process or something close to that.
[url=http://www.hawthorneaudio.com/forums/viewtopic.php?f=2&t=1429&p=20995&hilit=enabl]hawthorne audio[/url]has detailed info on applying EnABL by Budp Nov 29-30,2007.
I don't know why the links look so funny but they work.
Cdc, Very interesting. I remember a fellow writing in Audio Amateur some years back about gluing felt strips on the face of a cone driver with the idea of breaking up standing waves and how well he thought that worked. If I decide to EnABL my drivers I will use the AVM acoustic paint instead of the paint sold in the kit. Tom
Albert, You would make a great candidate to do the brass for steel swap out. Lotsa drivers lotsa steel. I performed that surgery on my Dunlavy 4's some years back. I used brass machine screws intead of wood screws. The machine screws had a higher number of threads and they extended all the way to the head unlike the wood screws. Made for a more tuneful sound that was also less noisey. Tom
Having been around audio for a long time and a past filled with car racing and engine building, when I say tighten with all my might I should have clarified the situation. Torx can be set up to fit two screwdriver handles or a ratchet drive. For something like a woofer I deliberately used the small handle Torx that limits leverage.
I don't know the exact amount I'm able to exert with the small drive, but it's like tightening brass parts on a carb when assembling an engine, you don't want to overdrive it and ruin the whole assembly.
I believe Dali must have used a locking compound on the screws, keeping the torque uniform over time. I have no proof but this behaves that way in my opinion.
No question that the ratchet handle and reverse motion could break the bond if a driver needed replacing, but I think they have it right where they want it and it was planned that way during assembly.
Albert, Maybe you can check with your Dali dealer or ask a factory technician about the torque. They might pre-torque these to factory specs and then, as you mentioned, they might put some lok-tite on the screws to keep them from loosening with time. It made me cringe to see that you couldn't tighten them with " all my strength..." You don't want to break off a screw or strip the wood out.
This thread made me wonder if my Dali Megalines might benefit from torquing the woofer screws. The ribbons are suspended in space, so they are non adjustable.
I removed the top section grill cloth on each side (of the six sections) and located in my tool chest, the Torx star bit that fit the mounting screws.
I was surprised that with all my strength I was unable to tighten any of the screws on six woofers that I checked. Granted, I gave up before testing all 24 woofers, but it appears that in the case of this particular speaker the screws have not backed off, or perhaps the factory applied a bonding agent, set the torque and it resists further movement.
Whatever the case, it was a grand experiment and got me to vacuum those dusty grill cloths. I'm looking forward to reports from others on the benefit of this. I love cheap tweaks that have potential to improve sound.
Thanks, Grant. I did start this thread, but I'm looking forward to some more positive posts( or negative, if that be the case) from others. Sometimes I feel like I'm talking to myself. Hey, wait a minute! I DO talk to myself! Anyway, I'd sure like to hear your impressions when your Fat Wrench comes in.
Tom, I understand the tuning by ear. Although I was experimenting with the torque using a screwdriver with a torque setting, I could hear the difference with each incremental setting. All this tweaking with the brass screws and proper torqueing not only puts the soundstage into perspective, but the best tone, timbre, and dynamics are also achieved when the setting is "just right". Currently, I am using some heavy metal stands filled with playground sand. My floor is a concrete slab that is carpeted with a 1/2" foam padding under the carpet. The stands have basic cheap steel spikes that came with the stands. I am considering buying some Audiopoints, but I have read that the Audiopoints are more effective on a wood floor. I am de-coupling my mini-monitors from the stands with squishy isonode feet.
Sherod, The torque to "tune" applied would vary from speaker to speaker. Cabinet structure and material.. driver frame material and even the number of fasteners.....T Nuts used? Hey what about speaker stands? Coupling or de-coupling materials? How about the flooring material, it too would make for a difference. Yea but its easy. Tom
Torque would indeed be a factor. As I said my bass driver,crossover and amp are tuned ..by ear. I have not recorded the settings by torque measurements but by ear and then recording the postion like the hands on a clock. During shipment of any device that is "tuned" at the factory the tuning will change in transit to the end user. The tuning will also "relax" with use. Retuning may also be required with changes in cables, electronics, tube brands and room acoustic additions. Increased resolution as I found with the addition of the modified Altmann Dac, D-Clock, PS Audio transport all AVM treated and Rick's magnetic replacement fuses made for quick apparent retuning by ear. Yep that feels right! Now sit down and enjoy. Right was obvious. Tom
Tom, besides switching to brass screws for your drivers, have you experimented with the torque? I'm curious what the proper torque should be for those inner screws for the tweeter, or maybe it depends on the type and brand of tweeter. I recall finding a thread on AA how the Merlin speaker driver's screws are properly torqued at the factory and some owners check for torque maybe twice a year. I remember that the inner screws on the tweeter are torqued higher than the outer screws.
The screws that matter most are those that hold the diaphragm and voice coil in place to the magnet assembly and face plate. The ferrous screws do just that, they screw with the field of flux as the coil moves back and forth in the gap. So the smallest speaker with the smallest coil is held in place with ferrous material at the closest distance to the motor assembly. Replace those screws one at a time that hold the dome in place. All of these that I have ever replaced have been metric size. Tom
The bass driver of my mains and its crossover both have resonance control brass tuning bolts that do make for a obvious change when tightened or loosened. My amps also can be tuned in a similar manner. Vibration can be given direction. Tom
My speakers are Reference 3a Dulcet. I e-mailed the main man, Tash, at Divergent Technologies and attached the VD video. He emailed me back telling me that the video was interesting and that it made sense to him. Tash asked me to run my personal tests with the brass screws and torque tests. I followed up telling him how the brass screws made a nice difference and explained to him how I came to fine-tuning the torque to achieve the best sound possible from the Dulcet. I suggested to him that he try his own tests in the factory and asked him for his results. So far, no answer from him. We'll see. I feel that this is a very good tweak and the laws of physics are in play here. I'm no physicist, but I'm thinking that the proper torque somehow is related to the screws matching the resonation of the cabinet with the speaker drivers. Perhaps someone can explain this phenomenon. It's obvious that the brass, being non-ferrous, doesn't negatively react with the driver magnets and brass has good drain-resonating characteristics. Help me here, tech guys.
Several years Rick came on these pages saying that the use of use of magnets in and around electronic circuitry was of great benefit. He got pushed around and laughed at as a result. He now uses magnets in many of his upper end designs. With more to come along. I used one magnet in a friends system, replaced the line fuse in his Bat 31SE preamp. The difference was huge and immediate. Now when music is played in the room his birds come down off their perch and sing and dance to tunes he has played way to many times before. Toe tapping I suppose. Sounds crazy but I've been there many times before. Maybe Rick will chime in to say why magnets work so well. Tom
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