[JLM]

I just picked up a new pair of speakers that I very briefly auditioned and then loaded them in a trailer for a 4 day, 900 mile trip home.  I hooked them up the next day and they sounded horrible (no treble, very limited dynamics).  Two more days later they suddenly opened up (treble and dynamics returned) quite nicely.  Reportedly the drivers were only half way through the recommended 500 hour (!) break-in period.  And even now the sound seems to improve as the listening session goes on.

The speakers use a single Fostex full range driver and I had the speakers laying on their sides for the trip home.  Temperatures in the trailer never reached 100 degrees as I checked on them regularly.  (I've heard of Lowthers doing some of this sort of thing due to the extremely close tolerances between their voice coil and magnets structures.)

Was this "re-break in" effect due to them "resting" for 5 days, laying on their sides while bouncing home, or what?  And what about this phenom of "opening up" the longer the music plays?  I suppose speakers can do the same as tube amps, but I've never experienced it before or heard of this happening with a Fostex driver.

Thanks for your ideas and opinions.

[Mike82]

In the cast of a multi driver speaker with a crossover, I suppose the crossover components might need some current running through them to get back into optimum operating condition. However a full range driver like the Fostex should sound pretty good right away.

Was there a different sound when you first heard them?  Maybe they weren't fully broken in like the seller pointed out.

[Chris_B]

Since speakers are mechanical devices, they will change some as the drivers and seals loosen up.  If you play 10+ hours of loud, dynamic music, they will likely show a nice improvement.

[ieales]

What about the electronics?

They were off for a similar length of time, no?

If I go on vacation, I power my electronics for 24 hours prior to listening.

[David Ellis]

I have found that my Bryston and old Kenwood amplifiers both sound better after being turned-on for about 30 minutes.  When I initially heard this I thought my ears were doing something odd/tricky.  I then learned that some amplifiers take a good long time to get warm.  I think this is the only valid reason why you might hear a change after a day of use.

In the case of your new speakers with the Fostex drivers, your ears might be breaking-in, but the drivers are already mostly broke-in after 20-30 hours of dynamic use.  There might be small changes up to the 100 hours but the changes will be quite small.  500 hours of use seems... well... very extreme.

Probably most imprtant is, how do they sound now?  Are you pleased?

Dave

[ieales]

for time and temperature effects

http://www.ielogical.com/winterblues.html

[JLM]

Thanks for all your responses:

Mike82,

What I heard at the time of pick-up and what I heard the first two days of listening at home was absolutely and completely different.  The brief audition at time of pick-up used a newer Panasonic player and non-descript Yamaha 5.1 receiver, so I didn't bother listening seriously to them.  Using his material they sounded very good, abet with the lack of bass imaging that the Fostex alnico drivers exhibit prior to full break-in.

As far as cross-over type issues go the speakers do include very simple solid state baffle step compensation circuits.  I've never heard of a two day warm-up of solid state circuits.


Chris B,

As I understand, it's the spiders (the suspension of the driver that loosens up, and yes I had about 10 hours of a variety of music on them at home when they "opened-up".  Acutually I was playing Holst's Planets (a very robust, dynamic, bass filled piece) and was it was during the Mars passage (with it's war overtones) that the bass drew my attention and I discovered that the treble and dynamics I had heard during the first audition was back.


ieales,

True, my equipment was off for 11 days prior, but as I mentioned above I've never heard anything remotely like this with solid state and I turn the stuff off whenever I leave the house for the day or longer.  Interesting read, but note that the temperatures of all the associated equipment remained between 75 and 90 degrees the entire time.  BTW guys that maintain heavy electronics prefer 85 degrees (just warm enough to keep condensation off the contact points).


David,

Again, I'd never noticed warm-up of solid state (including my Rotel amp or Sony CD player) anywhere close to this.  As you stated, I'd blame my ears acclaimating first, but this was a very obvious to the point of wondering if I'd somehow broken them or worse.

The guy I bought the speakers from was the cabinet designer/builder.  I had purchased the drivers from Madisound and they were shipped directly to him.  His first step was to burn the drivers in for 20 - 30 hours, then measure the T/S parameters to verify they matched and to develop a design based on actual measurement versus published specifications.  BTW users of Fostex alnico drivers routinely confirm that 500 hours of break-in is required.  These are not the typical high efficiency, whizzer cone Fostex drivers.  They have 2 pound alnico magnets and the frame is machined 3/8 inch aluminum.

[ctviggen]

My Jeff Rowland amplifier burns quite a bit of power (85 watts) to keep everything relatively warm to reduce warm up time.  I've not noticed any warm up time for electronics (although now I do have a tube CD player), but I've never actually sat and critically listened in the first so many minutes.  I almost always turn on the stuff, let it warm up while I'm doing something else, then listen.

[JLM]

Oh and I should have mentioned that my Rotel has a "keep circuits warm" feature (using only about 5 watts I seem to recall), so I rarely ever fully shut it entirely off.

[Steve Rothermel]

I've confirmed over many years of experience that the solid state stuff requires about 40 minutes of "burn in" after initial fire-up before the soundstage opens up and the treble stops calling attention to itself. The bass becomes more authoritative also. And I hear it consistently. I can tell you almost exactly when I hear the change.

George Short of North Creek tells me the break in for speakers involves as much settling in of the cone diaghram material and doesn't require bass-heavy recordings (as we would assume for loosening up the spiders and surround). He recommends playing midrange-heavy recordings and not necessarily at high volumes, to accomplish this.

I don't have experience with breaking in Fostex or other full-range drivers so I can't comment on those types but George's explanation may be relevant in this case. He mentioned such factors as the resins or treatments to the cone as the suspects in needing the excersize in loosening things up.

[JLM]

Steve,

This break-in was the opposite (treble was missing, bass was heavy/muddy, but imaging was there).  Again, the Rotel was left in the "stay warm" mode while gone and the drivers reportedly had about 250 hours on them.  My speaker designer/builder believes that a 20 - 30 initial run in should be sufficient prior to measuring the T/S parameters (which he did to confirm that the drivers matched and to tweak the design).

I would think that the trip I took them on is no worse than how they might be transported via commercial carriers, but somehow the sound at home was nothing like what I had heard prior to the trip.

Thankfully they're sounding very nice now and will make a full report once I'm comfortable and fully familiar with them.

[Steve Rothermel]

I'd suggest the settling in may be with familiarization with the new loudspeakers in your room. You'd mentioned at the outset that you had briefly auditioned them. Your listening skills may be excellent; so it still may be down to  acclimatization with the loudspeakers in a new (different) setting.

I'll bet that the qualities that made you buy them are there and that you can get them to perform as expected with proper room treatments...(please follow up).