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Derrick

Is a test tone from an iPad even remotly accurate?

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So, I downloaded a test tone generator on my iPad to see if the specs that my speakers are supposedly able to play were even close to accurate. The spec sheet says that they can play down to 20hz which I think is very  optimistic. I went through the frequency range with the tone generator and I can clearly hear sound from the woofers at 20-21hz. I am not going to buy additional equipment to verify this. Just wondering if anyone with more knowledge has an opinion on whether or not the test is even remotely accurate. 

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8 minutes ago, jimjimbo said:

The question is....which speakers?

 

Avid 330 from 1989. 12 inch woofers, acoustic suspension design. 

 

 

Avid 330.jpg

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You need to do a sweep and record the relative output. For example, my La Scalas have output below 40Hz, but relative to  400Hz, it's a few db lower.

 

Bruce

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8 hours ago, Derrick said:

 

Avid 330 from 1989. 12 inch woofers, acoustic suspension design. 

 

 

Avid 330.jpg

 

WTH is a voice coyle??  What's the story of those speakers?  Tons of spelling, grammatical and punctuation errors on that tag. 

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I suggest using a cheap RMS voltmeter (or borrow one) and measuring the AC voltage out at low, middle and high frequencies. Is the AC output within 10-15% across these frequencies. If so, then it is accurate enough. If it is off by 50%, then that is off by 6dB, If it is down by 30% that is about 3 dB. 

 

That is for the output. As far as the input (the exact frequency), it will be close enough. 

 

Now, the big question regards the speaker  output (you have only measured the voltage going into the speaker). That is the open question .... it depends on the speaker. That will require a microphone. Measuring this at very low frequencies can be problematic (mic placement and speaker location relative to walls, corners, etc).

 

Good Luck,

-Tom 

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They call it a sub woofer, but list no bass driver. Looks like they are saying that driver goes from 20 to where the midrange picks up, hard to believe. Also hard to believe that design goes from 20hz - 20mhz, must be in the Wokmanship as they say ?

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14 hours ago, Derrick said:

This is the original brochure. It lists the low end at 35 hz +-3db.

That would be closer to believable.

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18 hours ago, wuzzzer said:

 

WTH is a voice coyle??  What's the story of those speakers?  Tons of spelling, grammatical and punctuation errors on that tag. 

That's for warranty purposes. When the voice coil blows, they only cover voice coyles. 😁

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They sound good to me so I guess that is all that really matters. I was under the impression that if the specs say from 35hz then I would not hear anything at 20hz. It seems more like a low amount of sound at 20 with full sound starting at 35.


Sent from my iPhone using Tapatalk

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I did a similar test. I wouldn't trust the app's accuracy. I've done a similar test on klf30s that said they go down into the teens hz. As long as you're happy. If you really want to know, get a mic and rew software to test it.

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55 minutes ago, Derrick said:

I was under the impression that if the specs say from 35hz then I would not hear anything at 20hz. It seems more like a low amount of sound at 20 with full sound starting at 35.


Sent from my iPhone using Tapatalk

 

Some times the woofer is moving violently/pulsing and making sound but its distortion. Just because its making a noise @ 20 hz doesn't mean its accurate to the input signal. A low frequency transducer will do some crazy things at or below its rated FS.

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You may be able to put 20 Hz into the speaker, but what you are likely hearing is harmonic distortion.

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Thank you for the education. Makes sense. I have an SVS sub to fill in the bottom end anyway.


Sent from my iPhone using Tapatalk

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