Before and after break in


mr man

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I have 4 15 inch subwoofers and different resellers are giving different specs its either 29 or 36 Hz fs is this after and before break in specs?
 

Slo_Ride

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29 and 36 is a big difference. What subs? Why are you going by what a reseller says instead of the actual specs of the subs?
 

THATpurpleKUSH

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I don’t know of any subs that change Fs after break in. One seller just has the wrong numbers.
This is a factually incorrect and complete ignorant statement.

When a driver's suspension loosens after break in, an inherent effect of the suspension softening is in fact a drop in fs.

The amount that fs changes depends on the driver and materials used to build it.

This change can be further backed up with equipment that can measure tsp data like the Klippel or Dayton DATS system by completing a before and after measurement of ts parameters.

That being said, manufacturer listed tsp data is rarely accurate and often manipulated by the manufacturer's marketing department. Often listed specs are an average from the production run.

The only true way to know is by physically measuring the data with a Klippel, DATS or other reputable accurate method.


edit: further example using a Blaupunkt GBW801 pre break on the left and post break in on the right.

Break in consisted of playing 25hz free air on roughly 25% power handling for 10 mins.

Note the roughly 14% drop in fs after break in, I still wouldn't call the #'s 100% accurate due to the vas measuring method needed for the DATSv2 but there's enough data there that I would call close enough to make analysis.


26141


compare that to what the manufacturer provides:

26144
 
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JRsmoothee

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he makes all sorts of factually incorrect statements.....as i stated in another post "he is the new forum hero/moron" and nobody should take advice from him
 
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Marve_Lous

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When a driver's suspension loosens after break in, an inherent effect of the suspension softening is in fact a drop in fs.

The amount that fs changes depends on the driver and materials used to build it.

This change can be further backed up with equipment that can measure tsp data like the Klippel or Dayton DATS system by completing a before and after measurement of ts parameters.

That being said, manufacturer listed tsp data is rarely accurate and often manipulated by the manufacturer's marketing department. Often listed specs are an average from the production run.

The only true way to know is by physically measuring the data with a Klippel, DATS or other reputable accurate method.


edit: further example using a Blaupunkt GBW801 pre break on the left and post break in on the right.

Break in consisted of playing 25hz free air on roughly 25% power handling for 10 mins.

Note the roughly 14% drop in fs after break in, I still wouldn't call the #'s 100% accurate due to the vas measuring method needed for the DATSv2 but there's enough data there that I would call close enough to make analysis.


View attachment 26141

compare that to what the manufacturer provides:

View attachment 26144
Good info. Learn something new everyday. Now I’m curious. Isn’t Fs a spec used in programs like winisd to design an enclosure? If so, if that figure will change after break in, how big of an effect does that have on the box you designed based on the pre break in figure?
 

Buck

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Good info. Learn something new everyday. Now I’m curious. Isn’t Fs a spec used in programs like winisd to design an enclosure? If so, if that figure will change after break in, how big of an effect does that have on the box you designed based on the pre break in figure?
Fs can change port velocity quite a bit at different frequencies. Fs can be important if it's really off.
 
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Buck

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Several manufacturers post T/s after a short break in. But a lot of recommendations for woofers are from playing them a lot. But I've ran across quite a few t/s parameters where they seem way off. Like memphis mojo6 vas was like 450 liters off.....
 

Marve_Lous

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Several manufacturers post T/s after a short break in. But a lot of recommendations for woofers are from playing them a lot. But I've ran across quite a few t/s parameters where they seem way off. Like memphis mojo6 vas was like 450 liters off.....
Ahh, so the manufacturer’s Fs is or should be the subs post break in figure. 👍🏼
 

THATpurpleKUSH

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Ahh, so the manufacturer’s Fs is or should be the subs post break in figure. 👍🏼
Ideally yes but that varies highly depending on the manufacturer.

A company like Sundown that monitors their quality control relatively closely, I would trust the tsp info they provide, esp since they pull data with a Klippel.

A less reputable company like Skar or a large company with a big production batch is more likely to provide an averaged crapshoot of numbers that in actuality will vary widely.
 
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Buck

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Ahh, so the manufacturer’s Fs is or should be the subs post break in figure. 👍🏼
Hopefully lol. That's where experience comes in with box designing like I do. I've done so many boxes that I know what subs are going to do in certain situations, regardless of what the t/s say. You can spot bad t/s in modeling software like winisd, or bbp6 or whatever. Designing boxes is largely an art form, when it comes to tuning and sometimes airspace. I mean I use very accurate math to calculate displacements and net airspace, but determine tuning and what size box a sub wants from t/s alone can be dangerous, because t/s is misleading sometimes or even often. I don't care what the situation is- whether it's box designing or rocket science or quantum physics- it doesn't matter what the math says, it matters how the situation actually works in reality. People get obsessed with numbers too much, and don't have enough experience to make an executive call. The t/s is an important but sometimes useless part of box designing. The real world doesn't lie fyi
 
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Slo_Ride

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Several manufacturers post T/s after a short break in. But a lot of recommendations for woofers are from playing them a lot. But I've ran across quite a few t/s parameters where they seem way off. Like memphis mojo6 vas was like 450 liters off.....
That's because Memphis Audio is trash. I hate that company. I'd buy Skar before them
 
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hispls

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This is a factually incorrect and complete ignorant statement.

When a driver's suspension loosens after break in, an inherent effect of the suspension softening is in fact a drop in fs.

The amount that fs changes depends on the driver and materials used to build it.

This change can be further backed up with equipment that can measure tsp data like the Klippel or Dayton DATS system by completing a before and after measurement of ts parameters.

That being said, manufacturer listed tsp data is rarely accurate and often manipulated by the manufacturer's marketing department. Often listed specs are an average from the production run.

The only true way to know is by physically measuring the data with a Klippel, DATS or other reputable accurate method.


edit: further example using a Blaupunkt GBW801 pre break on the left and post break in on the right.

Break in consisted of playing 25hz free air on roughly 25% power handling for 10 mins.

Note the roughly 14% drop in fs after break in, I still wouldn't call the #'s 100% accurate due to the vas measuring method needed for the DATSv2 but there's enough data there that I would call close enough to make analysis.


View attachment 26141

compare that to what the manufacturer provides:

View attachment 26144
This is all true and the specs you have posted seem to change roughly as much as I'd expect to be consistent with woofers I have measured. Also I would say that after 10 minutes of hard play (or whatever test tone ritual you prefer) you shouldn't expect much more variance in the future. The vast majority of TSP change from suspension softening happens very quickly.

As to what manufacturers chose to publish, who knows who is doing what, but as an interesting aside I pulled TS paremeters from an old Clarion 32" woofer that belongs to a friend and got precisely the specs that Clarion published back in the 90s. I've pulled some specs from midranges as well that lined up within a very tight tolerance of published.
 
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Buck

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This is all true and the specs you have posted seem to change roughly as much as I'd expect to be consistent with woofers I have measured. Also I would say that after 10 minutes of hard play (or whatever test tone ritual you prefer) you shouldn't expect much more variance in the future. The vast majority of TSP change from suspension softening happens very quickly.

As to what manufacturers chose to publish, who knows who is doing what, but as an interesting aside I pulled TS paremeters from an old Clarion 32" woofer that belongs to a friend and got precisely the specs that Clarion published back in the 90s. I've pulled some specs from midranges as well that lined up within a very tight tolerance of published.
I'd be interested in seeing a thread with tested parameters vs posted parameters by the manufacturer.
 
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hispls

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I'd be interested in seeing a thread with tested parameters vs posted parameters by the manufacturer.
Not sure how many people buying factory made subs own the measuring equipment (or care to set up a test bench to measure and do the math long-hand). Or for that matter how many people who bought measuring equipment (probably to measure stuff they're building) who will buy off-the-shelf subs.

In any event 15% give or take variance in Fs, Vas, and Qts is to be expected after you stretch out the suspension for a few songs.
 
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