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Author Topic: Max SPL on a sub  (Read 6248 times)

Helge Dr. Bentsen

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Max SPL on a sub
« on: May 02, 2017, 02:51:52 am »

Is there a reliable and practical method of determining the real-world SPL from a subwoofer "in the field"?

I'm building a prototype for a sub and wish to have some idea about how much SPL it put's out within it's intended bandwidth.

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Chris Grimshaw

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Re: Max SPL on a sub
« Reply #1 on: May 02, 2017, 03:59:45 am »

My usual test method is this:

- Set processing etc as normal.
- Play pink noise
- Increase volume until bad sounds start, or the amp clips/limits
- Record SPL

If you want more complicated than that, you need to start reading here: http://www.data-bass.com/systems

Chris
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Ivan Beaver

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Re: Max SPL on a sub
« Reply #2 on: May 02, 2017, 07:14:09 am »

Is there a reliable and practical method of determining the real-world SPL from a subwoofer "in the field"?

I'm building a prototype for a sub and wish to have some idea about how much SPL it put's out within it's intended bandwidth.
It depends.

Are you looking for the maximum SPL that it can produce at some freq?

Or the maximum it can produce in the intended bandwidth?

Are you looking for the maximum "listenable SPL"?

What are you using to determine this SPL? What is the response time of the meter?  What is the weighting used?

You can easily come up with a different answer to each of the these questions-from the same speaker cabinet.

So first you have to narrow down the meaning of the question.  Different people can see the same question different ways.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
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David Sturzenbecher

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Re: Max SPL on a sub
« Reply #3 on: May 02, 2017, 07:49:47 am »

Helge, this may be what you are looking for

http://www.prosoundtraining.com/site/synaudcon-library/the-loudspeaker-toaster-test-revisited/


Sent from my iPhone using Tapatalk Pro
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Keith Broughton

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Re: Max SPL on a sub
« Reply #4 on: May 02, 2017, 08:34:19 am »

It depends.

Are you looking for the maximum SPL that it can produce at some freq?

Or the maximum it can produce in the intended bandwidth?

Are you looking for the maximum "listenable SPL"?

What are you using to determine this SPL? What is the response time of the meter?  What is the weighting used?

You can easily come up with a different answer to each of the these questions-from the same speaker cabinet.

So first you have to narrow down the meaning of the question.  Different people can see the same question different ways.
Also, what SPL at what distortion level?
(Sigh)...It's never easy  ::)
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Ivan Beaver

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Re: Max SPL on a sub
« Reply #5 on: May 02, 2017, 10:37:18 am »

Also, what SPL at what distortion level?
(Sigh)...It's never easy  ::)
What distortion at what freq?  The distortion number changes with freq-kind of like the impedance changes with freq.

A "simple single number" does not accurately describe the whole operation.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

Helge Dr. Bentsen

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Re: Max SPL on a sub
« Reply #6 on: May 02, 2017, 03:13:43 pm »

Helge, this may be what you are looking for

http://www.prosoundtraining.com/site/synaudcon-library/the-loudspeaker-toaster-test-revisited/


Sent from my iPhone using Tapatalk Pro

That looked similar to what I've been thinking about. Thanks for the link :)

Ivan: I wish to address two things: RMS limiter threshold to keep the sub from releasing it's magic smoke and a number I can tell people who will ask "how loud is it". I'm fully avare that this is not a simple question, so let's try to narrow it down.
I have Smaart 7, a DPA 4007, a SPL calibrator and a Powersoft K20.
I wish to be able to measure the maximum SPL the sub can produce for an extended time (3minutes or more) without failure within it's intended bandwith(hp/lp and eq in place), preferably with the same kind of accurancy that any reliable manufacturer would have on a SPL number in the datasheets for a high quality subwoofer.
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Jeff Permanian

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Josh Ricci

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Re: Max SPL on a sub
« Reply #8 on: May 03, 2017, 01:09:42 pm »

That looked similar to what I've been thinking about. Thanks for the link :)

Ivan: I wish to address two things: RMS limiter threshold to keep the sub from releasing it's magic smoke and a number I can tell people who will ask "how loud is it". I'm fully avare that this is not a simple question, so let's try to narrow it down.
I have Smaart 7, a DPA 4007, a SPL calibrator and a Powersoft K20.
I wish to be able to measure the maximum SPL the sub can produce for an extended time (3minutes or more) without failure within it's intended bandwith(hp/lp and eq in place), preferably with the same kind of accurancy that any reliable manufacturer would have on a SPL number in the datasheets for a high quality subwoofer.

Hello,

Chris already posted a link to my site earlier, the link is in my sig,  but I would suggest browsing around there starting with the "know how" section which briefly describes the equipment, measurements used and then check a few links to the subwoofer measurements. The "know how" section is a little out of data but it gives a close enough idea to how and why the measurements are taken. I have been doing something similar to what you are asking about for about 10 years. A quick tip is that you need to click on the system name and then the measurements tab to get to the full measurements packet for each unit. It can be a bit of information overload but as mentioned by others the correct answer will never be a simple 1 data point answer. At minimum there would have to be a number of qualifiers to that number. Anyway if you have any questions I'd be happy to help. I wish there were many more people qualifying their speakers in this manner.
« Last Edit: May 03, 2017, 01:16:15 pm by Josh Ricci »
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Marjan Milosevic

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Re: Max SPL on a sub
« Reply #9 on: May 09, 2017, 07:27:18 pm »

Most often the max spl data is calculated.
Honestly i would not bother trying to measure the real max data because as a figure has very little to the real world usage.
What is the most important is the sustained spl that it can produce with AES power rating applied to the drivers.
Then there is the program power handling and program SPL. Now this is now very tricky mater. Program power handling is always calculated figure by simply doubling the power. But things are far from this simple.
Music material varies in dynamics, and while live gigs can have great dynamics and program power is not a problem to the drivers, modern recorded music is quite compressed and average dynamic is quite smaller, thus average power sent to the drivers is much higher. Meaning they will most probably blow up with program power applied.
And all this does not account for the power compression. So the max spl figure to me is a pure fiction in real world use. But everyone love putting big numbers because they look good on paper. This force everyone to do the same, or they then look weak on paper.
Its a spec war there, and it is ugly.
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