Closed box driver Qts?

moray james · 19th April 2011, 06:03 AM

I know that horn loading requires a low Qts and reflex cabinets like a Qts of 0.35 for optimum flat response. What's the optimum driver Qts for sealed boxes? Thanks, best regards Moray James.

Josephjcole · 19th April 2011, 12:29 PM

I would have to think it depends on your definition of optimum. Also wouldn't the "optimum" Qts depend on Fs? Sorry no answers from me, only more questions

Joe

Top Shelf · 19th April 2011, 03:06 PM

Recommended sealed Qts is usually 0.4 and above, though Qtc (0.5-1.2) determines
response. Recommended ported Qts is usually 0.5 and below.

infinia · 19th April 2011, 03:13 PM

Quote:

Recommended sealed Qts is usually 0.4 and above

I would do not think upper range is boundless, unless peaky bass is your thing.

Top Shelf · 19th April 2011, 03:25 PM

Of course not

but due to infinite variable T/S specs of drivers and endless tastes in the finished response of immeasurable people, it can get quite high. I have used drivers with 0.75 - 0.85 Qts and they are a pain to get good response out of in my chosen boxes.

chris661 · 19th April 2011, 03:40 PM

They (various sites I've seen) reckon between 0.4 and 0.7.
Higher, it's only really useful for IB or OB applications, the output peak around resonance would be too much for a sealed box, it'd need to be mahoosive.

Lower Qts will give an earlier roll off, but a smaller box. Higher will get flat response closer to Fs, but needs a bigger box to do so. Take your pick - it's all compromises.

Chris

Top Shelf · 04:01 PM

Mahoosive! Good one

I've have good results with 0.5-0.6 Qts for sealed. Of course high power handling and large Xmax help.

geraldfryjr · 19th April 2011, 04:48 PM

Quote:

Originally Posted by Josephjcole

I would have to think it depends on your definition of optimum. Also wouldn't the "optimum" Qts depend on Fs? Sorry no answers from me, only more questions

Joe

You must remember that the final Qts is detremined from the box volume.
.707 is considered flat
Graphicaly I prefer .9 and any more than this things start to become boomy. jer

chris661 · 19th April 2011, 04:50 PM

Don't some people prefer Qc=0.5 for optimum transient response and better integration with room gain and stuff?

geraldfryjr · 19th April 2011, 04:52 PM

Good point.
I was going to add that but you beat me to it. jer

19th April 2011, 06:03 AM	#1
moray james diyAudio Member Join Date: Aug 2003 Location: Calgary on the Bow	Closed box driver Qts? I know that horn loading requires a low Qts and reflex cabinets like a Qts of 0.35 for optimum flat response. What's the optimum driver Qts for sealed boxes? Thanks, best regards Moray James. __________________ moray james

19th April 2011, 03:06 PM	#3
Top Shelf diyAudio Member Join Date: Apr 2010 Location: Midland, Ontario	Recommended sealed Qts is usually 0.4 and above, though Qtc (0.5-1.2) determines response. Recommended ported Qts is usually 0.5 and below. __________________ JEREMY M_________________________________ I like it loud, BUT NOT TOO LOUD!.... Hey do you hear that high pitched ringing sound ?

19th April 2011, 03:25 PM	#5
Top Shelf diyAudio Member Join Date: Apr 2010 Location: Midland, Ontario	Of course not but due to infinite variable T/S specs of drivers and endless tastes in the finished response of immeasurable people, it can get quite high. I have used drivers with 0.75 - 0.85 Qts and they are a pain to get good response out of in my chosen boxes. __________________ JEREMY M_________________________________ I like it loud, BUT NOT TOO LOUD!.... Hey do you hear that high pitched ringing sound ?

19th April 2011, 03:40 PM	#6
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	They (various sites I've seen) reckon between 0.4 and 0.7. Higher, it's only really useful for IB or OB applications, the output peak around resonance would be too much for a sealed box, it'd need to be mahoosive. Lower Qts will give an earlier roll off, but a smaller box. Higher will get flat response closer to Fs, but needs a bigger box to do so. Take your pick - it's all compromises. Chris __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html

19th April 2011, 03:47 PM	#7
Top Shelf diyAudio Member Join Date: Apr 2010 Location: Midland, Ontario	Mahoosive! Good one I've have good results with 0.5-0.6 Qts for sealed. Of course high power handling and large Xmax help. __________________ JEREMY M_________________________________ I like it loud, BUT NOT TOO LOUD!.... Hey do you hear that high pitched ringing sound ? Last edited by Top Shelf; 19th April 2011 at 04:01 PM.


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19th April 2011, 12:29 PM	#2
Josephjcole diyAudio Member Join Date: Jun 2004 Location: Wisconsin	I would have to think it depends on your definition of optimum. Also wouldn't the "optimum" Qts depend on Fs? Sorry no answers from me, only more questions Joe

19th April 2011, 04:50 PM	#9
chris661 diyAudio Member Join Date: Feb 2008 Location: Lancashire Blog Entries: 7	Don't some people prefer Qc=0.5 for optimum transient response and better integration with room gain and stuff? __________________ "Throwing parts at a failure is like throwing sponges at a rainstorm." - Enzo My setup: http://www.diyaudio.com/forums/multi...tang-band.html

19th April 2011, 04:52 PM	#10
geraldfryjr diyAudio Member Join Date: Feb 2008 Location: Jackson,michigan	Good point. I was going to add that but you beat me to it. jer

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