How sealed is sealed?

fb · 17th November 2009, 12:50 PM

How can I tell if my sealed boxes are sealed well enough? There doesn't seem to be any shortage of bass, but I've not tried anything too arduous.

Is it possible to tell from these impedance graphs?

Glowbug · 17th November 2009, 01:00 PM

As long as your cuts were straight, joints are tight, used adequate glue/sealant...I wouldn't worry too much about it

Zen Mod · 17th November 2009, 01:23 PM

take 3V battery

apply voltage to speaker ; disconnect ;

if speaker is really sealed , then cone will travel back much slowly comparing to same speaker in BR box or out of box ;

you can try to listen around baskets of all drivers in box - every air leak is pretty easy to hear

be careful , don't push your ear in cone

Eva · 17th November 2009, 01:51 PM

Are both plots from two copies of the same speaker? One reveals a resonance around 160Hz that is probably adding colouration...

badman · 17th November 2009, 02:41 PM

and the other has lots of small ripples.... I think it's box stuffing time!

Dr.EM · 17th November 2009, 03:21 PM

Is sealant required around the inside joins if the panels have been bonded with glue all along? If so, what is suitable to use?

richie00boy · 17th November 2009, 03:25 PM

No you don't need sealent if your glue joints are sound. I just run my finger along the excess anyway to act as a sealer.

planet10 · 17th November 2009, 04:21 PM

Quote:

Originally Posted by Eva

Are both plots from two copies of the same speaker? One reveals a resonance around 160Hz that is probably adding colouration...

You beat me too it... likely a panel that is not well enuff braced.

dave

markus76 · 17th November 2009, 08:14 PM

I don't worry too much about sealing any more. Even drilled a whole (1/16") in the back of my speakers to allow for static air pressure equalization because I had the feeling the box was too airtight.

Best, Markus

Iain McNeill · 17th November 2009, 10:06 PM

If you want to tell from the impedance curve, you have to compare it to the impedance curve for the same driver in free air, away from reflective surfaces. When you put the driver in the enclosure, the impedance peak will shift up and the Q will rise in accordance with the T-S relationships with Vas and Vb. If you're not getting all the frequency & Q rise, then there must be a leak.

Joseph d'Appolito's "Testing Loudspeakers" explains all.

17th November 2009, 01:00 PM	#2
Glowbug diyAudio Member Join Date: Feb 2006 Location: Hillsborough, NC/McLean, VA	As long as your cuts were straight, joints are tight, used adequate glue/sealant...I wouldn't worry too much about it __________________ Jim J.

17th November 2009, 01:23 PM	#3
Zen Mod diyAudio Member Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain	take 3V battery apply voltage to speaker ; disconnect ; if speaker is really sealed , then cone will travel back much slowly comparing to same speaker in BR box or out of box ; you can try to listen around baskets of all drivers in box - every air leak is pretty easy to hear be careful , don't push your ear in cone __________________ my Papa is smarter than your Nelson ! tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; BAF Forum & Gallery;I'm dumb

17th November 2009, 01:51 PM	#4
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	Are both plots from two copies of the same speaker? One reveals a resonance around 160Hz that is probably adding colouration... __________________ I use to feel like the small child in The Emperor's New Clothes tale

17th November 2009, 02:41 PM	#5
badman Custom Title diyAudio Member Join Date: Sep 2003 Location: Sunny Tustin, SoCal	and the other has lots of small ripples.... I think it's box stuffing time! __________________ I write for www.enjoythemusic.com in the DIY section. You may find yourself getting a preview of a project in-progress. Be warned!

17th November 2009, 03:21 PM	#6
Dr.EM diyAudio Member Join Date: Oct 2006 Location: Swindon	Is sealant required around the inside joins if the panels have been bonded with glue all along? If so, what is suitable to use? __________________ My music page 3-Way system build thread


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17th November 2009, 03:25 PM	#7
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	No you don't need sealent if your glue joints are sound. I just run my finger along the excess anyway to act as a sealer. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

17th November 2009, 08:14 PM	#9
markus76 diyAudio Member Join Date: May 2008 Location: Switzerland	I don't worry too much about sealing any more. Even drilled a whole (1/16") in the back of my speakers to allow for static air pressure equalization because I had the feeling the box was too airtight. Best, Markus

17th November 2009, 10:06 PM	#10
Iain McNeill diyAudio Moderator Join Date: Oct 2007 Location: Santa Cruz, California	If you want to tell from the impedance curve, you have to compare it to the impedance curve for the same driver in free air, away from reflective surfaces. When you put the driver in the enclosure, the impedance peak will shift up and the Q will rise in accordance with the T-S relationships with Vas and Vb. If you're not getting all the frequency & Q rise, then there must be a leak. Joseph d'Appolito's "Testing Loudspeakers" explains all.

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