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Understanding measurements


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#1 murrmax

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Posted 01 March 2012 - 11:28 AM

I'm slowly getting my head around what all the measurements mean but starting with the basics , these are measurements I made indoor and outdoor on the bass cabinet.

Outdoors there's one significant drop at around 39hz

Indoors there's a drop at 33hz a spike at 37hz and another drop at 42hz

Both measurements were made with mic around 20mm at cone centre

The lounge has wooden floors and wonder if that's causing the spike at 37k? floor is not particularly solid and could be a bit of a passive radiator.

But it's the 39hz drop outdoors that i'm initially trying to understand the reason, winisd indicated a steady rolloff as it does but the big dip I don't understand..

otherwise i'm happy with the frequency response measurements; for mid and highs both pretty flat in their respective ranges,

#2 murrmax

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Posted 01 March 2012 - 05:59 PM

Ah, the box's resonant frequency is 39hz, as intended well close enough to 40, question is what to do about it?

#3 davewantsmoore

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Posted 02 March 2012 - 08:13 AM

the bass cabinet


Tell us more. Much more. dave wants moore :)


.... I believe you're on the right track with box tuning, ports, etc. .... however, I'm waiting for somebody smarter so I can learn from them :-)

#4 murrmax

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Posted 02 March 2012 - 04:59 PM

Im guessing that when the box tuning frequency meets the speaker driver frequency they effectively cancel each other out to some degree,

#5 davewantsmoore

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Posted 03 March 2012 - 10:34 AM

Don't guess. However, nobody is going to be able to help you without much more info. Box size, tuning, port size/position, driver, rescaled graphs.

#6 Nigel

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Posted 03 March 2012 - 10:50 AM

room dimensions, different colours, nice font,...
If the US govt can force Coca Cola off the market until they removed cocaine from their product,
then govts can do the same to cigarette companies who add nicotine to their product.
Raising revenue is not an excuse for allowing manufacturers to use addiction to sell product.
Imagine the public outrage if supermarkets put addictive chemicals in meat or vegetables.

#7 murrmax

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Posted 03 March 2012 - 02:34 PM

Ok, when the weather clears i'll take a speaker outside and do it properly; room dimensions I can do, not sure about fonts & colours though..