The Loudspeaker Break-In Process

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Robert C. Schult

The Loudspeaker Break-In Process
« on: 26 Aug 2006, 06:39 pm »
Since the break-in process is (we, obviously, believe) an issue common to all cone-type (dynamic) loudspeakers, the principles mentioned in this email exchange will be useful for owners of other makes of loudspeakers.

From time to time we get comments on how long it takes for the Sason Ltd to break in. I wanted to share a recent purchaser's same concerns and address some other items with him that I hope will answer other owner's questions or others that may take interest in owning one of the world's finest full range monitors, regardless of price (and certainly not $22,000/pr.)

Steve Rothermel
Engineer/Associate
Ridge Street Audio Designs


-----Original Message-----

From: David Tackes [mailto:dtackes@wavecable.com]
Sent: Saturday, August 26, 2006 8:02 AM
To: Ridge Street Audio
Subject: After 50 Hours

Hello Steve,

I've been off-site a lot lately so I haven't had a chance to put the cones under the stands or level them yet but they continue to break in at about 15 hours a day.  I am a bit nervous about tipping them to insert the cones but I'll figure it out.  The carpet they're on has a pretty thick pad under it so that is one major reason they are pointing up in the air a little - the back is heavier.  Besides your cones, I also have some very nice (and heavy duty) cones that came with my Rowland's [amplifiers - SR].  They are the same height, have a larger top diameter but more importantly have a steeper angle. The reason I mention it, if the Sason cones don't pierce the thick carpet and pad to make them stable, I may try the Rowland cones.

Anyway after 50 hours....

·   The soundstage is noticeably bigger
·   Human voices are more focused
·   The tonality or timber of instruments still is not quite right
·   They still sound constrained

My wife still favors the Sound Labs and their huge presentation.  They were excellent speakers so it's not any easy task to compete with them.  I know what the Sason's can do so we'll see what she thinks as we continue on and I get them set up better and get more break in time on them.

So far I'm happy with the progress - just impatient.  I appreciate being able to email you with progress reports.

Regards,
David

_______________________________________ __________________________________


Hello David,
 
(I know this is long but I think you can appreciate gaining some insight into the technical nature of why you hear what you do at this point.)
 
Yep - these are all issues totally in line with the nature of break-in. The tonality/timber issue is related to two items.
 
The first is capacitor break-in, which is affected by internal materials, their polarization and dielectric values, static build-up (and dissipation over break-in) and other issues that are not fully understood in the audio engineering community. This issue is related to the constricted nature you describe as well as depth of field, focus, coherence, and liquidity or "grainless-ness" and upper-harmonic and top octave reproduction.
 
The second has to do with the fiber matrix of the Kevlar woofer cone and its suspension spider (the cloth-like ring of material holding the voice coil in place behind the woofer cone).
 
As things begin to normalize with the woofer cone, the event taking place within the woofer cone diaphragm is a "relaxing" of the Kevlar fibers and the binding epoxies that help give the cone its general shape. As it relates to musical timber and tonality, the center section of the cone affects a greater change through this relaxation process than the outer portion of the cone, since the upper harmonics (i.e. the higher frequencies where our hearing is most sensitive) are reproduced nearer the center. This definitely affects the manner of reproducing micro dynamics and timber/tonality as you can imagine.
 
The suspension spider in the Sason Ltd is designed to have a long travel range, which implies additional surface area (and more material) of the Sason Ltd spider over conventional spiders. Therefore, the break-in process takes a little longer on the Sason Ltd spider than others due to this "larger" spider. This relates to the tonality/timber issue and to a lesser degree the constricted sound.
 
These long-term issues are a challenge for determining the true "normalized" character of a driver and can play hell on a loudspeaker designer, not to mention a driver manufacturer. This is a great reason to trust Scan-Speak drivers. I know that they arrive on a final design based on data proven out with totally familiar break-in characteristics. Their listening trials happen over very long periods of time with drivers that represent what the consumer can expect after owning the product for many years. Timber and tonality are key items that can only be determined through drivers that are fully normalized.
 
Since the process is slow for these break in items (and hence one reason for our 45-day money back guarantee) you can expect to miss a single defining moment that indicates finality of break-in. In other words, patience and confidence will be the guiding factors to get through this! ;) I know it is a pain in the a__ but it will surprise you how far things can come. The biggest thing I still find uncomfortable to get through is the constricted nature of the sound during break-in. It definitely is an uninvolving sound until one day, while you are distracted with other tasks, a particular passage from a recording will jump out to capture your attention. That is when you will know you are over-the-hump with the break-in process. After that, the Sasons surpass nearly all other two-ways in dynamics - whether micro- or macro-. And they will play very loudly without constriction!
 
You will find the timber and tonality will improve once the damping materials are in the stand pillars. The bass improves as well - quicker, tighter, cleaner.
 
Do not be afraid to tip the Sason/stand to get the cones under the stand! I assume you have the wife or an assistant to place the cones while you tip it forward. As long as you are grasping the top plate of the stand while tipping the rear up (i.e. holding the plate underneath the speaker cones), nothing will catch you off-guard. Tip: placement location of the cones is not critical! Just get them near the edges but not poking out. Have your assistant place the cones (flat side up) against the underside of the granite base while the stand is tipped up, and then slide the cones to their approximate location. Also, it helps to place a small piece of tape on the granite base to indicate where center is for the front cone...this measurement is 4" over from the side edges.
 
I know the rear-heavy nature of the speaker/stand assembly is a bit awkward. (A concession toward aesthetics.) You will find by adding the lead shot to the front pillars the balance will improve appreciably. The Rowland cones sound like a good alternative to ours for piercing the carpet. However, you may be surprised to find ours making good contact with the subfloor. Your call!
 
Since you and the wife were accustomed to the large panel's sound presentation, I can imagine it will take quite a while to acclimate to what we believe is the truer reproduced sound image and soundstage. That is quite a paradigm shift between loudspeaker design philosophies. Eliminating the constricted nature the Sasons present during break-in will go a long way and you can expect quite a change over the next 50 to 100 hours. Can you tell me, David, with what other cone-type loudspeakers you have spent time?
 
In addition, I would like to know if the overall frequency response balance, top-to-bottom, is similar to the Sound Labs in your room. If there is a radical difference, it can suggest we need to readjust the room acoustics for the change in speakers. Balance is critical - it is the difference between a speaker you can live with versus one you cannot live without.
 
I appreciate that you are emailing me with progress reports.
 
Steve
 

« Last Edit: 26 Aug 2006, 07:31 pm by Robert C. Schult »