Acceleratied Speaker Breakin

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skyboltone
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Acceleratied Speaker Breakin

Post by skyboltone » Sun Dec 07, 2008 5:33 am

Ok, so let's say we follow Jim's (Southbay) procedures for breaking in speakers.

What happens if we bolt a pair of identical speakers, face to face then wire them to the variac out of phase. One blows, the other sucks, then they switch duties.

Will we have identical excursions as with in phase wiring, or larger excursions?

Will the phase cancellation make the process less noisy?

Would a white noise generator thru an cranked amp be slower? Better? Less effective? What?

Thanks for thinkin'
Dan
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Andy Le Blanc
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Re: Acceleratied Speaker Breakin

Post by Andy Le Blanc » Sun Dec 07, 2008 2:38 pm

that sounds like an isobaric pair, I think there is some cancelation. like a band pass?
you might want to have a break in pattern that includes a variety of tone. noise and impulse.
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Re: Acceleratied Speaker Breakin

Post by billyz » Sun Dec 07, 2008 7:07 pm

I would not expect a phase cancellation if they are wired out of phase to each other. It should actually extend the excursion of the cones. Might want to be careful of over excursion. I think to speed up the breakin process I would use some Acetone around the suspension and even the spider along with the cone movement to loosen the suspension up.

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Re: Acceleratied Speaker Breakin

Post by Scumback Speakers » Sun Dec 07, 2008 8:14 pm

I've got a 100 watt M75-LHDC sitting in my Grendel Dead Room next to me set up with my variac on top of it as I type.

A couple of thoughts for you. You don't want to bolt speakers cone to cone to each other since they need the air gap to move properly. Bolting them together will restrict the cone/suspension movement. Doing it out of phase might help, but you can't expect a perfect movement of "one in, one out" since no two speakers are identical. That means it would have to limit the movement of at least one, if not both. I'd put them in an ISO cab, or in a closed room, garage or closet, cone up, magnet down, and let them "burn in".

As for the "white noise" setup, never tried it. I use the 60 cycle hum of the variac, the cones bounce up and down about 1/8" constantly so that movement is within the excursion limits of the speaker, so you won't damage it that way from "over-excursion". Don't exceed the voltages as the constant heat might damage the coils if you go beyond it. This is setup as 1/3rd the power rating, which should be plenty safe. Going beyond those ratings is definitely "proceeding at your own risk".

The absolute best way of breaking in a speaker is to just play it at higher volumes...period. The speaker will move more this way and break in faster. I have tested that theory to destruction.

One of my clients got four 25 watt M75's. I told him 20-25 hours at decent volumes (20-25 watts). He played his 50 watt on 9 for 10 hours, and emailed me to say that they sounded all broken in to him, and if they got better he'd email me again. He hasn't, so I'm figuring they sound the same (or better) but not any more significantly broken in. His levels were about double what the variac formula provides, so this made sense to me. He also has a soundproof basement, so he's better off than most.

Now if you can dial in your volume for 10-20 hours at levels the speaker moves most at, then you're golden.

I'm going to figure most of you can't play your 50 watt at 6-8 for anything more than 20 minutes or until the cops slap the cuffs on you, so short of that, the variac will work wonders.

Granted, a full break in is 20 hours per speaker. You can do multiples if wired in parallel at the same voltages. Serial wiring doubles the time needed (twice as long for two, four times as long for four and so on).

Variac break in times:

Speaker Imp--Speaker Power Rating--Break in Voltage--How Long?
8----------------- 30w----------------- 8.9----------------- Light = 2 to 3 hours
8----------------- 65w----------------- 13.16-------------- Medium = 8-10 hours
8 -----------------100w ----------------- 16.325------------- Full = 18-20 hours


16-----------------30w----------------- 12.64
16-----------------65w----------------- 18.61
16-----------------100w----------------- 23.094

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Re: Acceleratied Speaker Breakin

Post by Andy Le Blanc » Sun Dec 07, 2008 8:15 pm

did some digging. when two speakers are used in that manner the suspension
of both drivers become coupled, they become twice as stiff, or half the compliance (the box can be half the size if a pair replaces a sigle driver)
and like push-pull with tubes it also reduces 2nd order distortion.
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Structo
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Re: Acceleratied Speaker Breakin

Post by Structo » Sun Dec 07, 2008 9:52 pm

Andy Le Blanc wrote:did some digging. when two speakers are used in that manner the suspension
of both drivers become coupled, they become twice as stiff, or half the compliance (the box can be half the size if a pair replaces a sigle driver)
and like push-pull with tubes it also reduces 2nd order distortion.
I don't know why but when it was mentioned about coupling the two speakers together cone to cone, the word "clam shell" came to mind.

I don't know if this is a legitimate term in speaker terminology or a flash back to the 70's.... :lol:

But how different would that coupling be compared to a sealed box enclosure?
I would guess since the speaker box holds more air in volume the buffering from the air behind the speaker wouldn't be as extreme as having the two speakers bolted together.

But it's an interesting topic like most guitar stuff is to me.

And thanks to Mr. Southbay, who's name escapes me for the moment, for the added info on speaker break in.
There are a lot of old wives tales floating around the internet so it's sometimes hard to separate fact from fiction.

Hey, maybe I ought to write the Mythbusters and see if they will do a program on speaker break in?

How about using a filament transformer?
I have heard of that being used before.

If you don't have a variac that would be a cheaper solution.
Tom

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Re: Acceleratied Speaker Breakin

Post by Andy Le Blanc » Sun Dec 07, 2008 11:13 pm

6.3 v across a 8 ohm load works out to around 5W rms, ok for low watt speakers,
but for drivers 50w and up it might not be so good, might not drive the coil enough to ensure cooling.
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Re: Acceleratied Speaker Breakin

Post by Jana » Sun Dec 07, 2008 11:27 pm

Ah, the isobaric phase modulation held in suspension whilst applying the acetone.
a break in pattern that includes a variety of tone. noise and impulse.
Send them to me, I generally achieve the later two of these three when playing. :)

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Structo
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Re: Acceleratied Speaker Breakin

Post by Structo » Sun Dec 07, 2008 11:33 pm

Andy Le Blanc wrote:6.3 v across a 8 ohm load works out to around 5W rms, ok for low watt speakers,
but for drivers 50w and up it might not be so good, might not drive the coil enough to ensure cooling.
Ok gottcha, and with 16 ohm speakers it's even less power.

So that is not a good solution.

There is a electronics surplus type store in my town.
They have some new Chinese variacs there.
I think the cheaper one was $50 but I don't remember the actual specs.

But it seems I've read some not so good reviews of these Chinese variacs.
Anybody know this for a fact?
Tom

Don't let that smoke out!

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Re: Acceleratied Speaker Breakin

Post by Fretts » Wed Dec 10, 2008 5:17 am

As I understand it, there are two major modes of break-in. The first is to loosen the suspension parts which include the cone surround or edge, and the spider, making them more flexible, more compliant and less resonant at a specific "boxy" sounding frequency. The cone moves as a single unit, like a piston. Anything that will work those flex points would do the trick; a filament transformer, a variac, a low B on a synthesizer, etc. This accounts for the majority of the difference between a new, raw, tight speaker and a broken-in one that has opened up.

The other mode is the cone "nodes", which is areas of the paper cone that flex distinctly from one another, in response to constant or transient music information. This means waves of a sort, that move across the paper, or along its length. The paper cone behaves not so much like a piston, but rather more like a waving flag, or an Australian wobble board. The areas in the paper that must flex to allow this to happen will also become looser and more flexible over time, presumably this would make the speaker sound even more open and musical. This is pretty esoteric, I know, but it is a known effect in the violin world as the reason that a much-played high-quality instrument "settles in" and becomes alive after some years. As far as I know, the only way to work that angle is to play varying music through the speaker to get it "used to" the frequencies of music, and in particular the instrument it is intended for.
Obviously, the #1 way to do that is to play guitar through the speaker - no surprise. It can be approximated by playing guitar-dominated recorded or broadcast music through it, let's say the local hard rock station for example, or a CD of Jeff Beck. Or Andreas Vollenweider.

Whether you couple two speakers face to face or not, it still only addresses the "piston" mode of break-in.

For all intents and purposes, mode #1 is plenty good enough. But since a speaker seems to open up even further after being played for awhile, even though it was broken in via the suspension-flex method, it's my opinion that this secondary type of break-in will take a speaker to that final phase where it is fully opened up and ready for business.

I could be full of it, but I don't see any compelling reason NOT to believe this.

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Re: Acceleratied Speaker Breakin

Post by Abstract » Wed Dec 10, 2008 3:04 pm

I have sprayed Fabreeze onto the cones of a couple speakers that I felt were too harsh. While they are moist, I like the sound...the bass and mids are accentuated, the highs are still there but smoother. It lasts for several days but a week or so later, the sound is back to normal. They sure smell nice though.

I've read that Fabreeze isn't a true "fabric softener", but more of a deodorizer...so I'll probably end up getting some Bounce or something and trying that.

The tech I used was dilute 1part Fabreeze with 4parts water and spray a fine mist over the speaker and surround (while they're being played). I "paint" the liquid onto the cone and surround with a foam brush. This darkens the speaker for awhile (even after it's dry)...for about a week...the same amt of time the speaker sounds good.

Leading me to believe...the fabreeze takes a few days to dry and what I like is the sound of a wet speaker. :?

Perhaps a true fabric softener would soften the fibers of the cone (permanently) and not evaporate?

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Re: Acceleratied Speaker Breakin

Post by skyboltone » Wed Dec 10, 2008 6:08 pm

Abstract wrote:I have sprayed Fabreeze onto the cones of a couple speakers that I felt were too harsh. While they are moist, I like the sound...the bass and mids are accentuated, the highs are still there but smoother. It lasts for several days but a week or so later, the sound is back to normal. They sure smell nice though.

I've read that Fabreeze isn't a true "fabric softener", but more of a deodorizer...so I'll probably end up getting some Bounce or something and trying that.

The tech I used was dilute 1part Fabreeze with 4parts water and spray a fine mist over the speaker and surround (while they're being played). I "paint" the liquid onto the cone and surround with a foam brush. This darkens the speaker for awhile (even after it's dry)...for about a week...the same amt of time the speaker sounds good.

Leading me to believe...the fabreeze takes a few days to dry and what I like is the sound of a wet speaker. :?

Perhaps a true fabric softener would soften the fibers of the cone (permanently) and not evaporate?
Wow Mat. That sure sounds scary. I think I'll pick up a couple of $250 Fanes from Dartanion and experiment with WD40.........just kidding.
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Abstract
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Re: Acceleratied Speaker Breakin

Post by Abstract » Mon Mar 02, 2009 9:26 pm

skyboltone wrote:
Abstract wrote:I have sprayed Fabreeze onto the cones of a couple speakers that I felt were too harsh. While they are moist, I like the sound...the bass and mids are accentuated, the highs are still there but smoother. It lasts for several days but a week or so later, the sound is back to normal. They sure smell nice though.

I've read that Fabreeze isn't a true "fabric softener", but more of a deodorizer...so I'll probably end up getting some Bounce or something and trying that.

The tech I used was dilute 1part Fabreeze with 4parts water and spray a fine mist over the speaker and surround (while they're being played). I "paint" the liquid onto the cone and surround with a foam brush. This darkens the speaker for awhile (even after it's dry)...for about a week...the same amt of time the speaker sounds good.

Leading me to believe...the fabreeze takes a few days to dry and what I like is the sound of a wet speaker. :?

Perhaps a true fabric softener would soften the fibers of the cone (permanently) and not evaporate?
Wow Mat. That sure sounds scary. I think I'll pick up a couple of $250 Fanes from Dartanion and experiment with WD40.........just kidding.

If anyone has any old Celestion Blues they aren't using...


Actually, I'm bumping this because I have some G12H30's in the cabinet I used to have the Vintage30's in...and while the G12's sound a metric shit-ton better...I still think I'd like to 'smooth' them out a bit. Just can't leave well enough alone.

I'll be starting with acetone on the surround. Then I will try actual FABRIC SOFTENER on the cone...no more of this 'fabric deodorizer' crap.



THEN....

I will either acetone or fabric soften the SPIDER!!!

Anyone screw with the spider for speaker breakin accelleration?
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Scumback Speakers
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Re: Acceleratied Speaker Breakin

Post by Scumback Speakers » Mon Mar 02, 2009 11:30 pm

I think you're about to either head into "No Man's Cone-Land" or have a significant breakthrough on "artificial aging"...be sure to let us know which.

Might help if you record and post some clips of the progress along the way, though... inquiring ears will want to know. :wink:

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Re: Acceleratied Speaker Breakin

Post by wscrane » Tue Mar 03, 2009 6:02 pm

Abstract wrote:[I will either acetone or fabric soften the SPIDER!!!

Anyone screw with the spider for speaker breakin accelleration?
No, but the spider is responsible for most of speaker stiffness, so if you can find an easy way to modify it, it makes more sense than messing with the surround.

By the way, I think what you're describing is "design change" not "break-in."

My experience is that good speakers require minimal or no break-in, and in cases where they don't sound good out of the box, break-in won't help much. I've found the effect of an extended break-in is subtle, mainly just a few Hz drop in the resonance.

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