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silverhairbp 30th January 2013 03:05 AM

Breakin question
 
I'm working with a pair of Alpair 10.2s. Mark's breakin recommendations call for 100 hours of low level music followed by gradually increasing the level until it reaches normal listening levels.

I'm currently about 72 hours into the breakin using the Telarc Vivaldi Four Seasons CD on continuous play (boy, is THAT exciting or what) at a low level not really audible if there's any other noise it the room. The drivers are NOT baffled, just sitting face-up on top of their cardboard boxes.

In a day and a half or so, I plan to change to a different CD, Bach Harpsichord Concertos (more bass and transients) and continue the breakin at a little louder level for a couple of days. I'll then change to something with a little more bass and increase the level for a few more days.

I'm patient. Plus, I'm a little behind schedule on constructing their enclosures. ;)

My questions start with how long does it really take for "full" breakin? Is there a risk of damage since they are not enclosed? Is this breakin plan overkill? How long until I can expect best performance?

Thanks,

Bill

Richard Ellis 30th January 2013 04:10 AM

No, no, no..........don't run your driver un-loaded other than the low-levels your doing now.
Remember, your driver either sealed or ported...mainly ported, as it approaches Fs & starts to "ring"..... the lack of enclosure will ram it past Xmax.
On one occasion (I don't do it anymore since)........I had a pair of Minimus 7 speakers & I decided to remove a driver as it was playing a decent volume.
The immediate lack of "acoustic suspension" had the driver banging against the 'stops', I was so startled at the "noise". What was once pleasant was now an angry growling sound....I almost dropped the driver, it was so nasty sounding.
Driver loading is the same.....free-air driven can easily whack-up the guts of our pride & joys...in a heart-beat.........especially these drivers which are typically just a few millimeters worth of Xmax.

__________________________________________________ ______Rick......

Richard Ellis 30th January 2013 04:43 AM

I would bet 'Mark' has a break-in procedure for his particular drivers.


__________________________________________________ ____Rick..........

silverhairbp 30th January 2013 05:06 AM

Quote:

Originally Posted by Richard Ellis (Post 3348126)
I would bet 'Mark' has a break-in procedure for his particular drivers.


__________________________________________________ ____Rick..........

Yes. I noted them in my original post. Here is the procedure from the 10.2 data sheet:

"For the first 100 hours, operate them at very low volumes. After this period, gradually increase the volume to a normal listening level. If you see the cone of the speakers making large movements, immediately turn the volume down."

My questions remain: How long does it really take for full breakin? Is this plan overkill? How long of a breakin before I can expect full performance?

zman01 30th January 2013 06:05 AM

silverhairbp,

What I have picked up from a number of discussions on break-in of MA Alpair drivers is:

1. Recommended music for initial period (100 hours?) should be of non-repetitive structures - i.e. soft jazz, vocal, acoustic, instrumentals without deep bass. Stuff like techno, pop, or rock with repetitive bass lines not recommended by Mark.

2. Volume levels should be "low" - it should be audible, but the cones should not move. Too low volumes (barely audible) is not likely to achive break-in.

3. After intital period mark advises introduction of some music with some rhythm/bass (but not rock/metal stuff :D)

4. Slowly increase the volume as the drivers get more hours on them - again nothing "loud"

5. For larger drivers (Alp 10, 12) ideally 4 hours of break-in playback at a time then a rest, for smaller drivers 6 hours of break-in at a stretch followed by a rest. Mark advises against playing the drivers non-stop.

6. For CHR/CHP drivers the break in period is less (150 hours)

If I have made any wrong assumptions/statements, please feel free to correct.

- Zia

silverhairbp 30th January 2013 02:18 PM

Thanks, Zia. This deviates a bit from the instructions provided on the data sheets. I will adjust accordingly.

I know it's been discussed, but how long is the typical breakin to get to full performance out of an A10.2?

It's not like I'm in a hurry. I just want to carefully get the drivers in the best condition they can attain.

mikje 30th January 2013 05:00 PM

I have apair of 10.2s that I broke in for the original period, 100 + hours in the boxes in which I recieved them. After that, I mounted them in the enclosures I built for them (Jim Griffin's MLTL) and have been listening to them as I break them in. It will take quite a while to get 300+ hours on them this way, but like you, I'm patient. I have noticed that they continue to improve in SQ as I play them more. I take this as evidence they are still breaking in. I've been pretty gentle with them, but I have been adding more volume to them a little at a time. I think the main idea is to start listening to them at moderate levels, and slowly increase the volume. For me, my typical listening volume is probably well below their capabilities. YMMV.
Bottom line... I'd recommend mounting them in their enclosures, listen to them this way, and gradually add volume to them.
Mike

soundnovice 30th January 2013 05:53 PM

low bass content for first 100h means can i take cutoff as 100hz? after filtering out low bass content can we play any music during breakin? also when we say low volume, how much dB we are talking about?

Scottmoose 30th January 2013 06:24 PM

There's a danger of over-complicating this. You don't need to start brickwall filtering or anything like that. Just use some material for the first 100 hours or so that doesn't have a heck of a lot of LF content, and play them quietly, so there is very little visible cone travel. This is not a matter that requires extreme precision, just some common sense. Afterwards, start lifting SPLs gradually, and begin to bring in some material with more low-end output. They'll continue to bed in for the next few hundred hours or so.

One point to stress. Although the MA drivers have a considerable Xmax (not that Xmax as a value means all that much without a heck of a lot of context & qualification), they won't thank you for hammering them with continuous 1/2in travel or similar. Few drive units will, and certainly not widebanders, where on top of the potential electromechanical distortions there are acoustical ones to think about too -FMD, AMD etc. As Mark points out, the travel is there for what in engineering terms he referrs to as 'shock loads', which in the world of audio are probably better known as occasional large low frequency dynamic peaks.

markaudio 1st February 2013 12:22 AM

Quote:

Originally Posted by soundnovice (Post 3348825)
low bass content for first 100h means can i take cutoff as 100hz? after filtering out low bass content can we play any music during breakin? also when we say low volume, how much dB we are talking about?

Hi Soundnovice,
Please DON'T filter out the bass. Remember you have a single cone driver that emits wide band (both mechanical oscillation and semi-stationary to stationary resonances). Its most important for the cone and power-train to receive full band, at low volumes while running in.

Ideally, drivers are best run-in when mounted in their speaker boxes but I appreciate many Diyers like to break-in the drivers in the pack boxes to save time. This is ok so long as they carefully choose music with modest bass and keep volumes low. Watch out for power-train movements that visually appear to exceed 1mm on the draw stroke (cone moving inwards) during the first 100 hours. Ease back the volume, or change the music if needed.

Cheers
Mark.


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