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(sciency) Measuring Speaker Performance?

593 Views 8 Replies 6 Participants Last post by  craig john
Hi,
So I'm not extremely well educated about audio and home theater.
I have learned enough to get myself into trouble and to buy some expensive speakers over the years when I catch them on sale.

I recently snapped up a few jbl sp8ii speakers. Fairly well rated, pretty expensive in-wall speakers. But I live in an apartment :)

To my naked ear, my much cheaper, housed, polk monitor 30 series ii bookshelves sound a lot better than these things when I simply hook them up and prop them against the wall.

Yes I understand that I'm not using the in-walls for what they were designed for.

I want to move forward with building boxes for the in-walls to see where I get. I will of course do reading on what people have found in the past. I'm not saying my plan is a great plan nor am I saying that I am doing the smartest thing.

However, I would like to know if any pro's out there have a way to test speakers that they would consider a valuable way to measure the performance of a speaker. If I play a frequency series and measure what the speaker produces using, say, a blue yeti microphone, would that be some sort of useful test?

I know I can't expect miracles, but I'd like to see what I can do that's better than using my ears and relying on subjective impressions.

Thank you!
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Measuring an inwall speaker, out of a wall, will always produce undesirable results.

Which is also why it sounds bad.
Measuring an inwall speaker, out of a wall, will always produce undesirable results.

Which is also why it sounds bad.
Thank you for taking the time to respond. I felt that I had acknowledged that it is to be expected that the speakers won't perform well when not used as intended.

The true purpose of my post is to ask about ways of measuring performance in a quantifiable way. That is to say, in a way that is repeatable and doesn't rely on opinion.
Thank you for taking the time to respond. I felt that I had acknowledged that it is to be expected that the speakers won't perform well when not used as intended.



The true purpose of my post is to ask about ways of measuring performance in a quantifiable way. That is to say, in a way that is repeatable and doesn't rely on opinion.

Ah.

Yes, they do make microphones and software for us consumers to measure our speakers.

Look up REW and/or Umik-1.

REW is the software, Umik-1 is the most common mic and is the least expensive for this purpose, good luck.
Thank you for taking the time to respond. I felt that I had acknowledged that it is to be expected that the speakers won't perform well when not used as intended.

The true purpose of my post is to ask about ways of measuring performance in a quantifiable way. That is to say, in a way that is repeatable and doesn't rely on opinion.
Like Russdawg said you can get a Umik 1 and REW to make measurements but you definitely need to put them in a box before doing that, the reason they sound bad is because the front wave of the woofer is cancelling with the back wave and making a mess of the frequency response.
You might want to buy Floyd Toole's book.
You might want to buy Floyd Toole's book.
Lots of free info on the website too.https://routledgetextbooks.com/textbooks/9781138921368/

Everything you want and need to know (and more) is in the book!
Thank you everyone! I really appreciate your help!
Like Russdawg said you can get a Umik 1 and REW to make measurements but you definitely need to put them in a box before doing that, the reason they sound bad is because the front wave of the woofer is cancelling with the back wave and making a mess of the frequency response.
The JBL SP8ii are an "infinite baffle" design. Before measurement, they should be put in a baffle, (such as a wall.) They should only be put in a box, if the optimal box volume is known. The box volume can be calculated from the Thiele-Small parameters of the driver, (if they are known.) https://en.wikipedia.org/wiki/Thiele/Small_parameters If they are not known, it is best to ask the manufacturer for the minimum box volume and the optimal box volume.

Craig
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