TechnologyCLD (Constraint Layer Damping)

Constraint Layer Dam­ping (CLD) is a mecha­nical engi­nee­ring method for the absorp­tion or mini­mi­zation of vibra­tions. In audio compo­nents CLD techno­logy is usually imple­mented by using sand­wich designs that ’embed’ a damping material layer between mate­rials that do not them­selves have suffi­cient dam­ping proper­ties. A cart­ridge will only track a record unaffec­ted, if it finds a quiet sur­face without reso­nance inter­feren­ces. Accor­dingly, it is neces­sary to deve­lop vibration-free chassis and platter designs – this must be done in addi­tion to the reso­nance-reducing mea­sures for motors, drive and bea­ring cons­truc­tion.

In order to achieve this, we already exten­ded the typical CLD techno­logy approach more than 20 years ago. Beyond the classic sand­wich cons­truc­tion, we presen­ted an absolute novelty to the high-end world: the Acoustic Signa­ture silencer platter, which imme­diately set new stan­dards in vibra­tion absorp­tion. Our twin-track CLD approach, which is mainly used in our high-mass turn­tables, is still unsur­passed in its effec­tiveness.

In the course of plan­ning and deve­lo­ping our NEO product line, we have been working inten­sively on impro­ving our CLD con­cept. First, our tests led to an opti­mized material combi­nation consis­ting of two layers of a special alu­minum alloy and an inter­mediate brass layer. Second, this also led to a new arrange­ment as well as an adjust­ment of size, weight and position of our silencer brass bolts when imple­mented in our platters.

In addition, we had to sensibly pair the two CLD tools descri­bed above with the NEO chassis to maxi­mize the effect. The elabo­rate material experi­ments and listening sessions were worth the efforts: in our NEO turn­table series we have succee­ded in taking the inter­action of all techno­logies to a stun­ning new level! A rigid, yet energy-absor­bing chassis based on finite element design princip­les, and our new CLD approach creates unbea­table units in terms of reso­nance behavior.

The CLD techno­logies that we imple­ment in the Acoustic Signa­ture NEO turn­table gene­ration have clearly excee­ded our metro­logical expec­tations and also show off in terms of sound perfor­mance – with an even blacker back­ground, larger ima­ging, increa­sed trans­parency and, above all, breath­taking musicality.

Since we invented the Silen­cer platter in 2000 we have conti­nuously impro­ved the perfor­mance results and have now achie­ved a platter dam­ping that is unbea­ten by any other product. The gold plated Silen­cers are of course visually attrac­tive and make the Acoustic Signa­ture turn­tables even more desi­rable than with­out them. But good looks was not the reason to imple­ment them into our products.

The Silencers absorb and reduce vibra­tions whilst the vinyl disk is play­ing and you are liste­ning. So, where do the vibra­tions come from, that we so wish to remove from the platter?

There are several sources. First, the cart­ridge needle itself, playing a record causes vibra­tions and reso­nance in the vinyl, due to the move­ment of the needle tracking the record groove. It’s easy to check by simply turning the volume down on your ampli­fier, you can still listen to the music directly from the needle/vinyl with your ear close to it. The needle is actually putting vibra­tion back into the record as it tracks the groove, cau­sing vibra­tion in the whole vinyl record. This leads to micro mis­tracking of the cart­ridge, when picked up by the needle along­side the actual signal you want from the track, with a very small time delay between the two. The Silen­cers in the platter absorb some of this unwan­ted vibra­tion and improve the sound reproduc­tion drama­tically.

The second source of vibra­tion is air waves hitting the platter and turn­table body from your loud­spea­kers whilst you’re liste­ning to music. Your cart­ridge/stylus doesn´t care where move­ment comes from, be it the grooves or other vibra­tions. Your cart­ridge simply produ­ces an electri­cal signal when vibra­ting and all vibra­tions coming through the turn­table will result in unwan­ted signals, resulting in a loss of detail reso­lution and imaging from your pre­cious vinyl records. The Silen­cers absorb these unwan­ted vibra­tions, lea­ding to a huge improve­ment in sound fidelity, impro­ving your liste­ning expe­rience.

To give you an idea how much the Silen­cers will improve the liste­ning expe­rience, we have con­duc­ted tests in an inde­pen­dent labo­ratory on two identi­cal platters, one with and one without eight silen­cers fitted. The results are dramatic.

50 mm platter without Silencers
Here you see the ringing of an alu­minum platter. A peak at about 2.2 kHz and multi­ples up to 15 kHz. The peaks are more than 80 dB louder than a damped platter!

50 mm platter with 8 Silencers
Here you see the result with 8 Silen­cers in the same alu­minum platter. Virtually all reso­nances and peaks are removed. The Silen­cers dampen the reso­nan­ces more than 80 dB.