Breaking in a subwoofer

[Brian Steele]

This evidence has changed my thinking about subwoofer break in!

The evidence also addresses the concern that neo-magnet subwoofers will lose magnet strength, as any such change would have adversely affected BL and Qes. Obviously that has not happened here, and this is a cheap neo-magnet sub.


B.

[- Rovin's car audio -]

do all manufacturers state the TS specs on the manual after a sub has broken in or when ts brand new ? ....

[i am an idiot]

So basically what he sayin is speakers would sound the same way from life start to end!

[Brian Steele]

do all manufacturers state the TS specs on the manual after a sub has broken in or when ts brand new ? ....

No idea. I do know that, if you're really interested in this stuff, you'd likely measure them yourself anyway (or get someone to measure it for you - takes 5~10 min with a WT3). Some manufacturers engage in a great deal of specmanship with their t/s specs, so it's a good idea to measure them anyway, if you're really interested in what they say about the driver's characteristics.

[Brian Steele]

So basically what he sayin is speakers would sound the same way from life start to end!

Nope. A subwoofer driver, being a mechanical system with moving components, will eventually start to fail, and the parameters will shift then, perhaps dramatically. I have drivers that haven't seen any significant change in parameters for over a decade though. OTOH, I don't abuse them either .

[jeff]

i think ppl are misinterpreting and generalizing in this thread

from reading through everyones posts you all have good points so no need for ppl to get all excited

brian has indicated that subs do change and that they cannot take full power and the tuners also mention that ppl damage subs by playing at full power etc but how many are actually interested in the actual sound quality or tonal characteristics of a subwoofer which is the real change in a subwoofer after "break in" rather than power handling???

99% of ppl damage subs through incorrect installation ie amp settings, gains levels,cross points and the number one culprit is incorrect enclosures NOT overpowering

and all these ppl talking about breaking in subs prob dont even do that. your sub will never get "full" power anyhow as not many ppl listen to test tones, which was cleared up already

so in reality you will never put "full power" on your subs and more than likely something else called clipping or distortion

so at the end of the day i think if you want to "break in your sub" then go ahead you got nothing to loose no need to fight about it

google will show a million ways to do it

[southside connections]

i am an idiot,


oh gadddddddd

99% of ppl damage subs through incorrect installation ie amp settings, gains levels,cross points and the number one culprit is incorrect enclosures NOT overpowering

[Brian Steele]

New driver measured specs :
Fs : 18.8 Hz
Qms :6.26
Qes : 0.49
Qts : 0.457

I should clarify something here. I took those measurements after I did my usual "excursion testing" to see how much noise was generated by the motor, among other things. It's entirely possible that this constituted "break-in" for the driver and the compliance of the driver changed during the process. However, we are talking about a period of an hour at most, not days and certainly not months!

In any case, Nousaine suggests in his article that his tests indicate that the compliance shift is irrelevant as far as performance is concerned - see my other post where I quote the relevant parts from his article.

It would be interesting to see opposing views on the matter, referring to actual test results, rather than name-dropping, to support their case. So far, I've yet to see this.

And, if you're curious, have a look at this link: http://www.icixsound.com/vb/showthread. ... ge=1&pp=10. There I queried the difference between a driver's measured and published t/s parameters on the manufacturer's forum, was told that I had to "break-in" the driver. I responded with subsequent test results indicating that break-in had no effect (to this day, the driver's specs are still much closer to my measurements rather than the manufacturer's published specs), and the manufacturer responded that I'm seeing different results because I'm using a different tester (hogwash, according to the tester's designer, and I agree with him - I mean, just because I use a different ruler, my inches will be different to yours? LOL).

I'm no longer able to post to that forum, btw.


B.

[DJ Q]

Ok I learned quite a lot from this thread but I also think the original topic was misinterpreted...

The original question was "how to break in a subwoofer"

Most people stated how to do it.
Brian went off to say that it doesn't change the how the sub plays, but what I think the real question is, is whether it is safe to drop a 1500wrms amp on a 1500wrms rated sub and play at full volume on it's first day out of the packaging, hence the need for the sub to be broken in.

That's the misinterpretation I see..

[INDAVID WORKSHOP]

Tell me guys I bought a Soundstream TS 12 subwoofer, followed the guidelines of half volume for one week, then 3/4 volume for the next week.

Now when the sub is played for about 45 mins at high volume it "smells" like rubber heating up, amp is the Soundstream 880.2.

Any help offered is welcome.

[southside connections]

thats just the vc set glue heating up, it eventually cures when it gets hot enough, basically, you won't have that smell for long again

[3stagevtec]

Tell me guys I bought a Soundstream TS 12 subwoofer, followed the guidelines of half volume for one week, then 3/4 volume for the next week.

Now when the sub is played for about 45 mins at high volume it "smells" like rubber heating up, amp is the Soundstream 880.2.

Any help offered is welcome.

make sure your gains are set correctly as well.. do a search if you don't know how to, there should be a few threads on the topic, if not, ask Google..

[INDAVID WORKSHOP]

thats just the vc set glue heating up, it eventually cures when it gets hot enough, basically, you won't have that smell for long again

[INDAVID WORKSHOP]

Tell me guys I bought a Soundstream TS 12 subwoofer, followed the guidelines of half volume for one week, then 3/4 volume for the next week.

Now when the sub is played for about 45 mins at high volume it "smells" like rubber heating up, amp is the Soundstream 880.2.

Any help offered is welcome.

make sure your gains are set correctly as well.. do a search if you don't know how to, there should be a few threads on the topic, if not, ask Google..

[exia_sir]

use it at mid volume for about a week n then gradually go up

[Brian Steele]

To keep things honest, a rep from Infinity did recently indicate that my 122.7Ws were "broken in before shipment". See http://www.diymobileaudio.com/forum/diy ... eriod.html. I don't know if he was being serious or not, LOL. I'm pretty sure that Infinity isn't going to hook up the sub to a test signal for a few weeks before packaging and selling it - doesn't make financial sense IMO. In any case, I've seen similar results with my Shivas and my eD 13Kv.2, the latter of which measured off-spec the day I got it and continues to measure so to this day...

[theblitz]

nice work there Brian

[Makko Jammah]

If your sub is 10" or more, and yuh does blast it all hours of the night at full volume with the intent of annoying everyone, me and my sledge hammer will be happy to help you ....

[DJ Q]

^running a sine sweep free air will not make any noise whatsoever.

[nervewrecker]

so does thread confirm weather or not there should be a break in period?

I will hold my tongue till further notice.

[- Rovin's car audio -]

ppl can do as they please but personally i choose to break in mine ...

[nervewrecker]

well thats the thing huh, some say yay & some say nay.

I am seeing results where it is confirmed that a shift in the parameters occur after the 'break in period' while I am seeing some say they have witnessed no such results.

so one of my question is: if a shift in parameters occur, how do manufacturers quote / give them out to the customer before these shifts in the parameters occur (provided that the subs were not 'broken in' by the manufacturer prior to shipping)?

[Brian Steele]

I am seeing results where it is confirmed that a shift in the parameters occur after the 'break in period'

Please post a link to such results.

[evolution7tt]

Let's say there is a change in T/S parameters. Are you going to be able to hear it?

Esp in a sealed enclosure application nervewrecker?

[nervewrecker]

I am seeing results where it is confirmed that a shift in the parameters occur after the 'break in period'

Please post a link to such results.

BNIB HAT L4SE. Break in @ 85hz for 2.5 hours near xmax. Driver sat for 30 minutes after break in and was tested again.

Before Break In (Fresh out of box):
Re = 4.1110 ohms
Fs = 102.8586 Hz
Zmax = 22.4491 ohms
Qes = 1.1264
Qms = 5.0247
Qts = 0.9201
Le = 0.1213 mH (at 1 kHz)
Diam = 79.0000 mm ( 3.1102 in )
Sd = 4901.6704 mm^2( 7.5976 in^2)
Vas = 1.4701 L ( 0.0519 ft^3)
BL = 3.6210 N/A
Mms = 5.5588 g
Cms = 430.7052 uM/N
Kms = 2321.7734 N/M
Rms = 0.7150 R mechanical
Efficiency = 0.1334 %
Sensitivity= 83.2711 dB @1W/1m
Sensitivity= 86.1626 dB @2.83Vrms/1m


After Break In:
Re = 4.1406 ohms
Fs = 97.3227 Hz
Zmax = 22.4715 ohms
Qes = 1.1078
Qms = 4.9043
Qts = 0.9037
Le = 0.1073 mH (at 1 kHz)
Diam = 79.0000 mm ( 3.1102 in )
Sd = 4901.6704 mm^2( 7.5976 in^2)
Vas = 1.3991 L ( 0.0494 ft^3)
BL = 3.8615 N/A
Mms = 6.5238 g
Cms = 409.9297 uM/N
Kms = 2439.4424 N/M
Rms = 0.8134 R mechanical
Efficiency = 0.1094 %
Sensitivity= 82.4080 dB @1W/1m
Sensitivity= 85.2683 dB @2.83Vrms/1m


Think about what we say changes due to break in and then think about what's not been discussed the past couple pages (hint: suspension... C & K (=1/C).

http://www.diymobileaudio.com/forum/car ... iod-7.html

I have 2 minds about posting it because there are both instances where shifts were reported with the same product & I dont want anyone saying that I against that brand.

[nervewrecker]

Let's say there is a change in T/S parameters. Are you going to be able to hear it?

Esp in a sealed enclosure application nervewrecker?

well honestly, when an enclosure is modeled it is done so by plugging in specific values in a program that gives a result. if some of these values were to change wouldnt how it responds / sounds in that enclosure change as well? I dont know, I am asking.

[Brian Steele]

I am seeing results where it is confirmed that a shift in the parameters occur after the 'break in period'

Please post a link to such results.

BNIB HAT L4SE. Break in @ 85hz for 2.5 hours near xmax. Driver sat for 30 minutes after break in and was tested again.

Before Break In (Fresh out of box):
Re = 4.1110 ohms
Fs = 102.8586 Hz
Zmax = 22.4491 ohms
Qes = 1.1264
Qms = 5.0247
Qts = 0.9201
Le = 0.1213 mH (at 1 kHz)
Diam = 79.0000 mm ( 3.1102 in )
Sd = 4901.6704 mm^2( 7.5976 in^2)
Vas = 1.4701 L ( 0.0519 ft^3)
BL = 3.6210 N/A
Mms = 5.5588 g
Cms = 430.7052 uM/N
Kms = 2321.7734 N/M
Rms = 0.7150 R mechanical
Efficiency = 0.1334 %
Sensitivity= 83.2711 dB @1W/1m
Sensitivity= 86.1626 dB @2.83Vrms/1m


After Break In:
Re = 4.1406 ohms
Fs = 97.3227 Hz
Zmax = 22.4715 ohms
Qes = 1.1078
Qms = 4.9043
Qts = 0.9037
Le = 0.1073 mH (at 1 kHz)
Diam = 79.0000 mm ( 3.1102 in )
Sd = 4901.6704 mm^2( 7.5976 in^2)
Vas = 1.3991 L ( 0.0494 ft^3)
BL = 3.8615 N/A
Mms = 6.5238 g
Cms = 409.9297 uM/N
Kms = 2439.4424 N/M
Rms = 0.8134 R mechanical
Efficiency = 0.1094 %
Sensitivity= 82.4080 dB @1W/1m
Sensitivity= 85.2683 dB @2.83Vrms/1m


Think about what we say changes due to break in and then think about what's not been discussed the past couple pages (hint: suspension... C & K (=1/C).

http://www.diymobileaudio.com/forum/car ... iod-7.html

I have 2 minds about posting it because there are both instances where shifts were reported with the same product & I dont want anyone saying that I against that brand.

IMO, those results are inconsequential to say the least, and the changes can be put down to measurement error or environment-induced variations (e.g. how would "break-in" affect Re, or even mms?). Also Qm, which is related to the driver's mechanical components and would be a prime candidate for a huge shift if "break-in" actually makes a difference, barely changes, from 4.9 to 5.0.

A better analysis would be a series of tests done at random times before, and then after, the "break-in" period. You'll likely find the same sort of variations in the measurements.

Alternatively, repeat the tests under very specific controlled conditions (e.g. ambient temperature and pressure, which can both affect the results if they vary between measurements).

[evolution7tt]

Nerve, don't even worry about a change in T/S. Build your enclosure based on manufacturer's suggestions OR have the woofer tested with a WT3.

[DJ Q]

I am seeing results where it is confirmed that a shift in the parameters occur after the 'break in period'

Please post a link to such results.

http://www.diymobileaudio.com/forum/car ... iod-7.html

I have 2 minds about posting it because there are both instances where shifts were reported with the same product & I dont want anyone saying that I against that brand.

IMO, those results are inconsequential to say the least, and the changes can be put down to measurement error or environment-induced variations (e.g. how would "break-in" affect Re, or even mms?). Also Qm, which is related to the driver's mechanical components and would be a prime candidate for a huge shift if "break-in" actually makes a difference, barely changes, from 4.9 to 5.0.

A better analysis would be a series of tests done at random times before, and then after, the "break-in" period. You'll likely find the same sort of variations in the measurements.

Alternatively, repeat the tests under very specific controlled conditions (e.g. ambient temperature and pressure, which can both affect the results if they vary between measurements).

Even if those results are confirmed... Most things barely changed. I am surprised that the sensitivity would go down... expected that to go up if the suspension is "looser"

It all comes down to my question: Can a woofer take the full rated power as soon as it's out of the box??

[nervewrecker]

I really dont know but despite what was said / concluded in here I still choose to be a bit old fashioned & gradually introduce my sub to more power.